diff options
Diffstat (limited to 'archivers/libarchive/files/libarchive/archive_read_support_format_rar5.c')
| -rw-r--r-- | archivers/libarchive/files/libarchive/archive_read_support_format_rar5.c | 4030 |
1 files changed, 4030 insertions, 0 deletions
diff --git a/archivers/libarchive/files/libarchive/archive_read_support_format_rar5.c b/archivers/libarchive/files/libarchive/archive_read_support_format_rar5.c new file mode 100644 index 00000000000..7c24627b186 --- /dev/null +++ b/archivers/libarchive/files/libarchive/archive_read_support_format_rar5.c @@ -0,0 +1,4030 @@ +/*- +* Copyright (c) 2018 Grzegorz Antoniak (http://antoniak.org) +* All rights reserved. +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* 1. Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* 2. Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in the +* documentation and/or other materials provided with the distribution. +* +* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR +* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#include "archive_platform.h" +#include "archive_endian.h" + +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif +#include <time.h> +#ifdef HAVE_ZLIB_H +#include <zlib.h> /* crc32 */ +#endif +#ifdef HAVE_LIMITS_H +#include <limits.h> +#endif + +#include "archive.h" +#ifndef HAVE_ZLIB_H +#include "archive_crc32.h" +#endif + +#include "archive_entry.h" +#include "archive_entry_locale.h" +#include "archive_ppmd7_private.h" +#include "archive_entry_private.h" + +#ifdef HAVE_BLAKE2_H +#include <blake2.h> +#else +#include "archive_blake2.h" +#endif + +/*#define CHECK_CRC_ON_SOLID_SKIP*/ +/*#define DONT_FAIL_ON_CRC_ERROR*/ +/*#define DEBUG*/ + +#define rar5_min(a, b) (((a) > (b)) ? (b) : (a)) +#define rar5_max(a, b) (((a) > (b)) ? (a) : (b)) +#define rar5_countof(X) ((const ssize_t) (sizeof(X) / sizeof(*X))) + +#if defined DEBUG +#define DEBUG_CODE if(1) +#else +#define DEBUG_CODE if(0) +#endif + +/* Real RAR5 magic number is: + * + * 0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x01, 0x00 + * "Rar!→•☺·\x00" + * + * It's stored in `rar5_signature` after XOR'ing it with 0xA1, because I don't + * want to put this magic sequence in each binary that uses libarchive, so + * applications that scan through the file for this marker won't trigger on + * this "false" one. + * + * The array itself is decrypted in `rar5_init` function. */ + +static unsigned char rar5_signature[] = { 243, 192, 211, 128, 187, 166, 160, 161 }; +static const ssize_t rar5_signature_size = sizeof(rar5_signature); +static const size_t g_unpack_window_size = 0x20000; + +/* These could have been static const's, but they aren't, because of + * Visual Studio. */ +#define MAX_NAME_IN_CHARS 2048 +#define MAX_NAME_IN_BYTES (4 * MAX_NAME_IN_CHARS) + +struct file_header { + ssize_t bytes_remaining; + ssize_t unpacked_size; + int64_t last_offset; /* Used in sanity checks. */ + int64_t last_size; /* Used in sanity checks. */ + + uint8_t solid : 1; /* Is this a solid stream? */ + uint8_t service : 1; /* Is this file a service data? */ + uint8_t eof : 1; /* Did we finish unpacking the file? */ + uint8_t dir : 1; /* Is this file entry a directory? */ + + /* Optional time fields. */ + uint64_t e_mtime; + uint64_t e_ctime; + uint64_t e_atime; + uint32_t e_unix_ns; + + /* Optional hash fields. */ + uint32_t stored_crc32; + uint32_t calculated_crc32; + uint8_t blake2sp[32]; + blake2sp_state b2state; + char has_blake2; + + /* Optional redir fields */ + uint64_t redir_type; + uint64_t redir_flags; +}; + +enum EXTRA { + EX_CRYPT = 0x01, + EX_HASH = 0x02, + EX_HTIME = 0x03, + EX_VERSION = 0x04, + EX_REDIR = 0x05, + EX_UOWNER = 0x06, + EX_SUBDATA = 0x07 +}; + +#define REDIR_SYMLINK_IS_DIR 1 + +enum REDIR_TYPE { + REDIR_TYPE_NONE = 0, + REDIR_TYPE_UNIXSYMLINK = 1, + REDIR_TYPE_WINSYMLINK = 2, + REDIR_TYPE_JUNCTION = 3, + REDIR_TYPE_HARDLINK = 4, + REDIR_TYPE_FILECOPY = 5, +}; + +#define OWNER_USER_NAME 0x01 +#define OWNER_GROUP_NAME 0x02 +#define OWNER_USER_UID 0x04 +#define OWNER_GROUP_GID 0x08 +#define OWNER_MAXNAMELEN 256 + +enum FILTER_TYPE { + FILTER_DELTA = 0, /* Generic pattern. */ + FILTER_E8 = 1, /* Intel x86 code. */ + FILTER_E8E9 = 2, /* Intel x86 code. */ + FILTER_ARM = 3, /* ARM code. */ + FILTER_AUDIO = 4, /* Audio filter, not used in RARv5. */ + FILTER_RGB = 5, /* Color palette, not used in RARv5. */ + FILTER_ITANIUM = 6, /* Intel's Itanium, not used in RARv5. */ + FILTER_PPM = 7, /* Predictive pattern matching, not used in + RARv5. */ + FILTER_NONE = 8, +}; + +struct filter_info { + int type; + int channels; + int pos_r; + + int64_t block_start; + ssize_t block_length; + uint16_t width; +}; + +struct data_ready { + char used; + const uint8_t* buf; + size_t size; + int64_t offset; +}; + +struct cdeque { + uint16_t beg_pos; + uint16_t end_pos; + uint16_t cap_mask; + uint16_t size; + size_t* arr; +}; + +struct decode_table { + uint32_t size; + int32_t decode_len[16]; + uint32_t decode_pos[16]; + uint32_t quick_bits; + uint8_t quick_len[1 << 10]; + uint16_t quick_num[1 << 10]; + uint16_t decode_num[306]; +}; + +struct comp_state { + /* Flag used to specify if unpacker needs to reinitialize the + uncompression context. */ + uint8_t initialized : 1; + + /* Flag used when applying filters. */ + uint8_t all_filters_applied : 1; + + /* Flag used to skip file context reinitialization, used when unpacker + is skipping through different multivolume archives. */ + uint8_t switch_multivolume : 1; + + /* Flag used to specify if unpacker has processed the whole data block + or just a part of it. */ + uint8_t block_parsing_finished : 1; + + int notused : 4; + + int flags; /* Uncompression flags. */ + int method; /* Uncompression algorithm method. */ + int version; /* Uncompression algorithm version. */ + ssize_t window_size; /* Size of window_buf. */ + uint8_t* window_buf; /* Circular buffer used during + decompression. */ + uint8_t* filtered_buf; /* Buffer used when applying filters. */ + const uint8_t* block_buf; /* Buffer used when merging blocks. */ + size_t window_mask; /* Convenience field; window_size - 1. */ + int64_t write_ptr; /* This amount of data has been unpacked + in the window buffer. */ + int64_t last_write_ptr; /* This amount of data has been stored in + the output file. */ + int64_t last_unstore_ptr; /* Counter of bytes extracted during + unstoring. This is separate from + last_write_ptr because of how SERVICE + base blocks are handled during skipping + in solid multiarchive archives. */ + int64_t solid_offset; /* Additional offset inside the window + buffer, used in unpacking solid + archives. */ + ssize_t cur_block_size; /* Size of current data block. */ + int last_len; /* Flag used in lzss decompression. */ + + /* Decode tables used during lzss uncompression. */ + +#define HUFF_BC 20 + struct decode_table bd; /* huffman bit lengths */ +#define HUFF_NC 306 + struct decode_table ld; /* literals */ +#define HUFF_DC 64 + struct decode_table dd; /* distances */ +#define HUFF_LDC 16 + struct decode_table ldd; /* lower bits of distances */ +#define HUFF_RC 44 + struct decode_table rd; /* repeating distances */ +#define HUFF_TABLE_SIZE (HUFF_NC + HUFF_DC + HUFF_RC + HUFF_LDC) + + /* Circular deque for storing filters. */ + struct cdeque filters; + int64_t last_block_start; /* Used for sanity checking. */ + ssize_t last_block_length; /* Used for sanity checking. */ + + /* Distance cache used during lzss uncompression. */ + int dist_cache[4]; + + /* Data buffer stack. */ + struct data_ready dready[2]; +}; + +/* Bit reader state. */ +struct bit_reader { + int8_t bit_addr; /* Current bit pointer inside current byte. */ + int in_addr; /* Current byte pointer. */ +}; + +/* RARv5 block header structure. Use bf_* functions to get values from + * block_flags_u8 field. I.e. bf_byte_count, etc. */ +struct compressed_block_header { + /* block_flags_u8 contain fields encoded in little-endian bitfield: + * + * - table present flag (shr 7, and 1), + * - last block flag (shr 6, and 1), + * - byte_count (shr 3, and 7), + * - bit_size (shr 0, and 7). + */ + uint8_t block_flags_u8; + uint8_t block_cksum; +}; + +/* RARv5 main header structure. */ +struct main_header { + /* Does the archive contain solid streams? */ + uint8_t solid : 1; + + /* If this a multi-file archive? */ + uint8_t volume : 1; + uint8_t endarc : 1; + uint8_t notused : 5; + + unsigned int vol_no; +}; + +struct generic_header { + uint8_t split_after : 1; + uint8_t split_before : 1; + uint8_t padding : 6; + int size; + int last_header_id; +}; + +struct multivolume { + unsigned int expected_vol_no; + uint8_t* push_buf; +}; + +/* Main context structure. */ +struct rar5 { + int header_initialized; + + /* Set to 1 if current file is positioned AFTER the magic value + * of the archive file. This is used in header reading functions. */ + int skipped_magic; + + /* Set to not zero if we're in skip mode (either by calling + * rar5_data_skip function or when skipping over solid streams). + * Set to 0 when in * extraction mode. This is used during checksum + * calculation functions. */ + int skip_mode; + + /* Set to not zero if we're in block merging mode (i.e. when switching + * to another file in multivolume archive, last block from 1st archive + * needs to be merged with 1st block from 2nd archive). This flag + * guards against recursive use of the merging function, which doesn't + * support recursive calls. */ + int merge_mode; + + /* An offset to QuickOpen list. This is not supported by this unpacker, + * because we're focusing on streaming interface. QuickOpen is designed + * to make things quicker for non-stream interfaces, so it's not our + * use case. */ + uint64_t qlist_offset; + + /* An offset to additional Recovery data. This is not supported by this + * unpacker. Recovery data are additional Reed-Solomon codes that could + * be used to calculate bytes that are missing in archive or are + * corrupted. */ + uint64_t rr_offset; + + /* Various context variables grouped to different structures. */ + struct generic_header generic; + struct main_header main; + struct comp_state cstate; + struct file_header file; + struct bit_reader bits; + struct multivolume vol; + + /* The header of currently processed RARv5 block. Used in main + * decompression logic loop. */ + struct compressed_block_header last_block_hdr; +}; + +/* Forward function declarations. */ + +static int verify_global_checksums(struct archive_read* a); +static int rar5_read_data_skip(struct archive_read *a); +static int push_data_ready(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, size_t size, int64_t offset); + +/* CDE_xxx = Circular Double Ended (Queue) return values. */ +enum CDE_RETURN_VALUES { + CDE_OK, CDE_ALLOC, CDE_PARAM, CDE_OUT_OF_BOUNDS, +}; + +/* Clears the contents of this circular deque. */ +static void cdeque_clear(struct cdeque* d) { + d->size = 0; + d->beg_pos = 0; + d->end_pos = 0; +} + +/* Creates a new circular deque object. Capacity must be power of 2: 8, 16, 32, + * 64, 256, etc. When the user will add another item above current capacity, + * the circular deque will overwrite the oldest entry. */ +static int cdeque_init(struct cdeque* d, int max_capacity_power_of_2) { + if(d == NULL || max_capacity_power_of_2 == 0) + return CDE_PARAM; + + d->cap_mask = max_capacity_power_of_2 - 1; + d->arr = NULL; + + if((max_capacity_power_of_2 & d->cap_mask) > 0) + return CDE_PARAM; + + cdeque_clear(d); + d->arr = malloc(sizeof(void*) * max_capacity_power_of_2); + + return d->arr ? CDE_OK : CDE_ALLOC; +} + +/* Return the current size (not capacity) of circular deque `d`. */ +static size_t cdeque_size(struct cdeque* d) { + return d->size; +} + +/* Returns the first element of current circular deque. Note that this function + * doesn't perform any bounds checking. If you need bounds checking, use + * `cdeque_front()` function instead. */ +static void cdeque_front_fast(struct cdeque* d, void** value) { + *value = (void*) d->arr[d->beg_pos]; +} + +/* Returns the first element of current circular deque. This function + * performs bounds checking. */ +static int cdeque_front(struct cdeque* d, void** value) { + if(d->size > 0) { + cdeque_front_fast(d, value); + return CDE_OK; + } else + return CDE_OUT_OF_BOUNDS; +} + +/* Pushes a new element into the end of this circular deque object. If current + * size will exceed capacity, the oldest element will be overwritten. */ +static int cdeque_push_back(struct cdeque* d, void* item) { + if(d == NULL) + return CDE_PARAM; + + if(d->size == d->cap_mask + 1) + return CDE_OUT_OF_BOUNDS; + + d->arr[d->end_pos] = (size_t) item; + d->end_pos = (d->end_pos + 1) & d->cap_mask; + d->size++; + + return CDE_OK; +} + +/* Pops a front element of this circular deque object and returns its value. + * This function doesn't perform any bounds checking. */ +static void cdeque_pop_front_fast(struct cdeque* d, void** value) { + *value = (void*) d->arr[d->beg_pos]; + d->beg_pos = (d->beg_pos + 1) & d->cap_mask; + d->size--; +} + +/* Pops a front element of this circular deque object and returns its value. + * This function performs bounds checking. */ +static int cdeque_pop_front(struct cdeque* d, void** value) { + if(!d || !value) + return CDE_PARAM; + + if(d->size == 0) + return CDE_OUT_OF_BOUNDS; + + cdeque_pop_front_fast(d, value); + return CDE_OK; +} + +/* Convenience function to cast filter_info** to void **. */ +static void** cdeque_filter_p(struct filter_info** f) { + return (void**) (size_t) f; +} + +/* Convenience function to cast filter_info* to void *. */ +static void* cdeque_filter(struct filter_info* f) { + return (void**) (size_t) f; +} + +/* Destroys this circular deque object. Deallocates the memory of the + * collection buffer, but doesn't deallocate the memory of any pointer passed + * to this deque as a value. */ +static void cdeque_free(struct cdeque* d) { + if(!d) + return; + + if(!d->arr) + return; + + free(d->arr); + + d->arr = NULL; + d->beg_pos = -1; + d->end_pos = -1; + d->cap_mask = 0; +} + +static inline +uint8_t bf_bit_size(const struct compressed_block_header* hdr) { + return hdr->block_flags_u8 & 7; +} + +static inline +uint8_t bf_byte_count(const struct compressed_block_header* hdr) { + return (hdr->block_flags_u8 >> 3) & 7; +} + +static inline +uint8_t bf_is_table_present(const struct compressed_block_header* hdr) { + return (hdr->block_flags_u8 >> 7) & 1; +} + +static inline struct rar5* get_context(struct archive_read* a) { + return (struct rar5*) a->format->data; +} + +/* Convenience functions used by filter implementations. */ +static void circular_memcpy(uint8_t* dst, uint8_t* window, const uint64_t mask, + int64_t start, int64_t end) +{ + if((start & mask) > (end & mask)) { + ssize_t len1 = mask + 1 - (start & mask); + ssize_t len2 = end & mask; + + memcpy(dst, &window[start & mask], len1); + memcpy(dst + len1, window, len2); + } else { + memcpy(dst, &window[start & mask], (size_t) (end - start)); + } +} + +static uint32_t read_filter_data(struct rar5* rar, uint32_t offset) { + uint8_t linear_buf[4]; + circular_memcpy(linear_buf, rar->cstate.window_buf, + rar->cstate.window_mask, offset, offset + 4); + return archive_le32dec(linear_buf); +} + +static void write_filter_data(struct rar5* rar, uint32_t offset, + uint32_t value) +{ + archive_le32enc(&rar->cstate.filtered_buf[offset], value); +} + +/* Allocates a new filter descriptor and adds it to the filter array. */ +static struct filter_info* add_new_filter(struct rar5* rar) { + struct filter_info* f = + (struct filter_info*) calloc(1, sizeof(struct filter_info)); + + if(!f) { + return NULL; + } + + cdeque_push_back(&rar->cstate.filters, cdeque_filter(f)); + return f; +} + +static int run_delta_filter(struct rar5* rar, struct filter_info* flt) { + int i; + ssize_t dest_pos, src_pos = 0; + + for(i = 0; i < flt->channels; i++) { + uint8_t prev_byte = 0; + for(dest_pos = i; + dest_pos < flt->block_length; + dest_pos += flt->channels) + { + uint8_t byte; + + byte = rar->cstate.window_buf[ + (rar->cstate.solid_offset + flt->block_start + + src_pos) & rar->cstate.window_mask]; + + prev_byte -= byte; + rar->cstate.filtered_buf[dest_pos] = prev_byte; + src_pos++; + } + } + + return ARCHIVE_OK; +} + +static int run_e8e9_filter(struct rar5* rar, struct filter_info* flt, + int extended) +{ + const uint32_t file_size = 0x1000000; + ssize_t i; + + circular_memcpy(rar->cstate.filtered_buf, + rar->cstate.window_buf, rar->cstate.window_mask, + rar->cstate.solid_offset + flt->block_start, + rar->cstate.solid_offset + flt->block_start + flt->block_length); + + for(i = 0; i < flt->block_length - 4;) { + uint8_t b = rar->cstate.window_buf[ + (rar->cstate.solid_offset + flt->block_start + + i++) & rar->cstate.window_mask]; + + /* + * 0xE8 = x86's call <relative_addr_uint32> (function call) + * 0xE9 = x86's jmp <relative_addr_uint32> (unconditional jump) + */ + if(b == 0xE8 || (extended && b == 0xE9)) { + + uint32_t addr; + uint32_t offset = (i + flt->block_start) % file_size; + + addr = read_filter_data(rar, + (uint32_t)(rar->cstate.solid_offset + + flt->block_start + i) & rar->cstate.window_mask); + + if(addr & 0x80000000) { + if(((addr + offset) & 0x80000000) == 0) { + write_filter_data(rar, (uint32_t)i, + addr + file_size); + } + } else { + if((addr - file_size) & 0x80000000) { + uint32_t naddr = addr - offset; + write_filter_data(rar, (uint32_t)i, + naddr); + } + } + + i += 4; + } + } + + return ARCHIVE_OK; +} + +static int run_arm_filter(struct rar5* rar, struct filter_info* flt) { + ssize_t i = 0; + uint32_t offset; + + circular_memcpy(rar->cstate.filtered_buf, + rar->cstate.window_buf, rar->cstate.window_mask, + rar->cstate.solid_offset + flt->block_start, + rar->cstate.solid_offset + flt->block_start + flt->block_length); + + for(i = 0; i < flt->block_length - 3; i += 4) { + uint8_t* b = &rar->cstate.window_buf[ + (rar->cstate.solid_offset + + flt->block_start + i) & rar->cstate.window_mask]; + + if(b[3] == 0xEB) { + /* 0xEB = ARM's BL (branch + link) instruction. */ + offset = read_filter_data(rar, + (rar->cstate.solid_offset + flt->block_start + i) & + rar->cstate.window_mask) & 0x00ffffff; + + offset -= (uint32_t) ((i + flt->block_start) / 4); + offset = (offset & 0x00ffffff) | 0xeb000000; + write_filter_data(rar, (uint32_t)i, offset); + } + } + + return ARCHIVE_OK; +} + +static int run_filter(struct archive_read* a, struct filter_info* flt) { + int ret; + struct rar5* rar = get_context(a); + + free(rar->cstate.filtered_buf); + + rar->cstate.filtered_buf = malloc(flt->block_length); + if(!rar->cstate.filtered_buf) { + archive_set_error(&a->archive, ENOMEM, + "Can't allocate memory for filter data."); + return ARCHIVE_FATAL; + } + + switch(flt->type) { + case FILTER_DELTA: + ret = run_delta_filter(rar, flt); + break; + + case FILTER_E8: + /* fallthrough */ + case FILTER_E8E9: + ret = run_e8e9_filter(rar, flt, + flt->type == FILTER_E8E9); + break; + + case FILTER_ARM: + ret = run_arm_filter(rar, flt); + break; + + default: + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported filter type: 0x%x", flt->type); + return ARCHIVE_FATAL; + } + + if(ret != ARCHIVE_OK) { + /* Filter has failed. */ + return ret; + } + + if(ARCHIVE_OK != push_data_ready(a, rar, rar->cstate.filtered_buf, + flt->block_length, rar->cstate.last_write_ptr)) + { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Stack overflow when submitting unpacked data"); + + return ARCHIVE_FATAL; + } + + rar->cstate.last_write_ptr += flt->block_length; + return ARCHIVE_OK; +} + +/* The `push_data` function submits the selected data range to the user. + * Next call of `use_data` will use the pointer, size and offset arguments + * that are specified here. These arguments are pushed to the FIFO stack here, + * and popped from the stack by the `use_data` function. */ +static void push_data(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, int64_t idx_begin, int64_t idx_end) +{ + const uint64_t wmask = rar->cstate.window_mask; + const ssize_t solid_write_ptr = (rar->cstate.solid_offset + + rar->cstate.last_write_ptr) & wmask; + + idx_begin += rar->cstate.solid_offset; + idx_end += rar->cstate.solid_offset; + + /* Check if our unpacked data is wrapped inside the window circular + * buffer. If it's not wrapped, it can be copied out by using + * a single memcpy, but when it's wrapped, we need to copy the first + * part with one memcpy, and the second part with another memcpy. */ + + if((idx_begin & wmask) > (idx_end & wmask)) { + /* The data is wrapped (begin offset sis bigger than end + * offset). */ + const ssize_t frag1_size = rar->cstate.window_size - + (idx_begin & wmask); + const ssize_t frag2_size = idx_end & wmask; + + /* Copy the first part of the buffer first. */ + push_data_ready(a, rar, buf + solid_write_ptr, frag1_size, + rar->cstate.last_write_ptr); + + /* Copy the second part of the buffer. */ + push_data_ready(a, rar, buf, frag2_size, + rar->cstate.last_write_ptr + frag1_size); + + rar->cstate.last_write_ptr += frag1_size + frag2_size; + } else { + /* Data is not wrapped, so we can just use one call to copy the + * data. */ + push_data_ready(a, rar, + buf + solid_write_ptr, (idx_end - idx_begin) & wmask, + rar->cstate.last_write_ptr); + + rar->cstate.last_write_ptr += idx_end - idx_begin; + } +} + +/* Convenience function that submits the data to the user. It uses the + * unpack window buffer as a source location. */ +static void push_window_data(struct archive_read* a, struct rar5* rar, + int64_t idx_begin, int64_t idx_end) +{ + push_data(a, rar, rar->cstate.window_buf, idx_begin, idx_end); +} + +static int apply_filters(struct archive_read* a) { + struct filter_info* flt; + struct rar5* rar = get_context(a); + int ret; + + rar->cstate.all_filters_applied = 0; + + /* Get the first filter that can be applied to our data. The data + * needs to be fully unpacked before the filter can be run. */ + if(CDE_OK == cdeque_front(&rar->cstate.filters, + cdeque_filter_p(&flt))) { + /* Check if our unpacked data fully covers this filter's + * range. */ + if(rar->cstate.write_ptr > flt->block_start && + rar->cstate.write_ptr >= flt->block_start + + flt->block_length) { + /* Check if we have some data pending to be written + * right before the filter's start offset. */ + if(rar->cstate.last_write_ptr == flt->block_start) { + /* Run the filter specified by descriptor + * `flt`. */ + ret = run_filter(a, flt); + if(ret != ARCHIVE_OK) { + /* Filter failure, return error. */ + return ret; + } + + /* Filter descriptor won't be needed anymore + * after it's used, * so remove it from the + * filter list and free its memory. */ + (void) cdeque_pop_front(&rar->cstate.filters, + cdeque_filter_p(&flt)); + + free(flt); + } else { + /* We can't run filters yet, dump the memory + * right before the filter. */ + push_window_data(a, rar, + rar->cstate.last_write_ptr, + flt->block_start); + } + + /* Return 'filter applied or not needed' state to the + * caller. */ + return ARCHIVE_RETRY; + } + } + + rar->cstate.all_filters_applied = 1; + return ARCHIVE_OK; +} + +static void dist_cache_push(struct rar5* rar, int value) { + int* q = rar->cstate.dist_cache; + + q[3] = q[2]; + q[2] = q[1]; + q[1] = q[0]; + q[0] = value; +} + +static int dist_cache_touch(struct rar5* rar, int idx) { + int* q = rar->cstate.dist_cache; + int i, dist = q[idx]; + + for(i = idx; i > 0; i--) + q[i] = q[i - 1]; + + q[0] = dist; + return dist; +} + +static void free_filters(struct rar5* rar) { + struct cdeque* d = &rar->cstate.filters; + + /* Free any remaining filters. All filters should be naturally + * consumed by the unpacking function, so remaining filters after + * unpacking normally mean that unpacking wasn't successful. + * But still of course we shouldn't leak memory in such case. */ + + /* cdeque_size() is a fast operation, so we can use it as a loop + * expression. */ + while(cdeque_size(d) > 0) { + struct filter_info* f = NULL; + + /* Pop_front will also decrease the collection's size. */ + if (CDE_OK == cdeque_pop_front(d, cdeque_filter_p(&f))) + free(f); + } + + cdeque_clear(d); + + /* Also clear out the variables needed for sanity checking. */ + rar->cstate.last_block_start = 0; + rar->cstate.last_block_length = 0; +} + +static void reset_file_context(struct rar5* rar) { + memset(&rar->file, 0, sizeof(rar->file)); + blake2sp_init(&rar->file.b2state, 32); + + if(rar->main.solid) { + rar->cstate.solid_offset += rar->cstate.write_ptr; + } else { + rar->cstate.solid_offset = 0; + } + + rar->cstate.write_ptr = 0; + rar->cstate.last_write_ptr = 0; + rar->cstate.last_unstore_ptr = 0; + + rar->file.redir_type = REDIR_TYPE_NONE; + rar->file.redir_flags = 0; + + free_filters(rar); +} + +static inline int get_archive_read(struct archive* a, + struct archive_read** ar) +{ + *ar = (struct archive_read*) a; + archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_support_format_rar5"); + + return ARCHIVE_OK; +} + +static int read_ahead(struct archive_read* a, size_t how_many, + const uint8_t** ptr) +{ + if(!ptr) + return 0; + + ssize_t avail = -1; + *ptr = __archive_read_ahead(a, how_many, &avail); + if(*ptr == NULL) { + return 0; + } + + return 1; +} + +static int consume(struct archive_read* a, int64_t how_many) { + int ret; + + ret = how_many == __archive_read_consume(a, how_many) + ? ARCHIVE_OK + : ARCHIVE_FATAL; + + return ret; +} + +/** + * Read a RAR5 variable sized numeric value. This value will be stored in + * `pvalue`. The `pvalue_len` argument points to a variable that will receive + * the byte count that was consumed in order to decode the `pvalue` value, plus + * one. + * + * pvalue_len is optional and can be NULL. + * + * NOTE: if `pvalue_len` is NOT NULL, the caller needs to manually consume + * the number of bytes that `pvalue_len` value contains. If the `pvalue_len` + * is NULL, this consuming operation is done automatically. + * + * Returns 1 if *pvalue was successfully read. + * Returns 0 if there was an error. In this case, *pvalue contains an + * invalid value. + */ + +static int read_var(struct archive_read* a, uint64_t* pvalue, + uint64_t* pvalue_len) +{ + uint64_t result = 0; + size_t shift, i; + const uint8_t* p; + uint8_t b; + + /* We will read maximum of 8 bytes. We don't have to handle the + * situation to read the RAR5 variable-sized value stored at the end of + * the file, because such situation will never happen. */ + if(!read_ahead(a, 8, &p)) + return 0; + + for(shift = 0, i = 0; i < 8; i++, shift += 7) { + b = p[i]; + + /* Strip the MSB from the input byte and add the resulting + * number to the `result`. */ + result += (b & (uint64_t)0x7F) << shift; + + /* MSB set to 1 means we need to continue decoding process. + * MSB set to 0 means we're done. + * + * This conditional checks for the second case. */ + if((b & 0x80) == 0) { + if(pvalue) { + *pvalue = result; + } + + /* If the caller has passed the `pvalue_len` pointer, + * store the number of consumed bytes in it and do NOT + * consume those bytes, since the caller has all the + * information it needs to perform */ + if(pvalue_len) { + *pvalue_len = 1 + i; + } else { + /* If the caller did not provide the + * `pvalue_len` pointer, it will not have the + * possibility to advance the file pointer, + * because it will not know how many bytes it + * needs to consume. This is why we handle + * such situation here automatically. */ + if(ARCHIVE_OK != consume(a, 1 + i)) { + return 0; + } + } + + /* End of decoding process, return success. */ + return 1; + } + } + + /* The decoded value takes the maximum number of 8 bytes. + * It's a maximum number of bytes, so end decoding process here + * even if the first bit of last byte is 1. */ + if(pvalue) { + *pvalue = result; + } + + if(pvalue_len) { + *pvalue_len = 9; + } else { + if(ARCHIVE_OK != consume(a, 9)) { + return 0; + } + } + + return 1; +} + +static int read_var_sized(struct archive_read* a, size_t* pvalue, + size_t* pvalue_len) +{ + uint64_t v; + uint64_t v_size = 0; + + const int ret = pvalue_len ? read_var(a, &v, &v_size) + : read_var(a, &v, NULL); + + if(ret == 1 && pvalue) { + *pvalue = (size_t) v; + } + + if(pvalue_len) { + /* Possible data truncation should be safe. */ + *pvalue_len = (size_t) v_size; + } + + return ret; +} + +static int read_bits_32(struct rar5* rar, const uint8_t* p, uint32_t* value) { + uint32_t bits = ((uint32_t) p[rar->bits.in_addr]) << 24; + bits |= p[rar->bits.in_addr + 1] << 16; + bits |= p[rar->bits.in_addr + 2] << 8; + bits |= p[rar->bits.in_addr + 3]; + bits <<= rar->bits.bit_addr; + bits |= p[rar->bits.in_addr + 4] >> (8 - rar->bits.bit_addr); + *value = bits; + return ARCHIVE_OK; +} + +static int read_bits_16(struct rar5* rar, const uint8_t* p, uint16_t* value) { + int bits = (int) ((uint32_t) p[rar->bits.in_addr]) << 16; + bits |= (int) p[rar->bits.in_addr + 1] << 8; + bits |= (int) p[rar->bits.in_addr + 2]; + bits >>= (8 - rar->bits.bit_addr); + *value = bits & 0xffff; + return ARCHIVE_OK; +} + +static void skip_bits(struct rar5* rar, int bits) { + const int new_bits = rar->bits.bit_addr + bits; + rar->bits.in_addr += new_bits >> 3; + rar->bits.bit_addr = new_bits & 7; +} + +/* n = up to 16 */ +static int read_consume_bits(struct rar5* rar, const uint8_t* p, int n, + int* value) +{ + uint16_t v; + int ret, num; + + if(n == 0 || n > 16) { + /* This is a programmer error and should never happen + * in runtime. */ + return ARCHIVE_FATAL; + } + + ret = read_bits_16(rar, p, &v); + if(ret != ARCHIVE_OK) + return ret; + + num = (int) v; + num >>= 16 - n; + + skip_bits(rar, n); + + if(value) + *value = num; + + return ARCHIVE_OK; +} + +static int read_u32(struct archive_read* a, uint32_t* pvalue) { + const uint8_t* p; + if(!read_ahead(a, 4, &p)) + return 0; + + *pvalue = archive_le32dec(p); + return ARCHIVE_OK == consume(a, 4) ? 1 : 0; +} + +static int read_u64(struct archive_read* a, uint64_t* pvalue) { + const uint8_t* p; + if(!read_ahead(a, 8, &p)) + return 0; + + *pvalue = archive_le64dec(p); + return ARCHIVE_OK == consume(a, 8) ? 1 : 0; +} + +static int bid_standard(struct archive_read* a) { + const uint8_t* p; + + if(!read_ahead(a, rar5_signature_size, &p)) + return -1; + + if(!memcmp(rar5_signature, p, rar5_signature_size)) + return 30; + + return -1; +} + +static int rar5_bid(struct archive_read* a, int best_bid) { + int my_bid; + + if(best_bid > 30) + return -1; + + my_bid = bid_standard(a); + if(my_bid > -1) { + return my_bid; + } + + return -1; +} + +static int rar5_options(struct archive_read *a, const char *key, + const char *val) { + (void) a; + (void) key; + (void) val; + + /* No options supported in this version. Return the ARCHIVE_WARN code + * to signal the options supervisor that the unpacker didn't handle + * setting this option. */ + + return ARCHIVE_WARN; +} + +static void init_header(struct archive_read* a) { + a->archive.archive_format = ARCHIVE_FORMAT_RAR_V5; + a->archive.archive_format_name = "RAR5"; +} + +enum HEADER_FLAGS { + HFL_EXTRA_DATA = 0x0001, + HFL_DATA = 0x0002, + HFL_SKIP_IF_UNKNOWN = 0x0004, + HFL_SPLIT_BEFORE = 0x0008, + HFL_SPLIT_AFTER = 0x0010, + HFL_CHILD = 0x0020, + HFL_INHERITED = 0x0040 +}; + +static int process_main_locator_extra_block(struct archive_read* a, + struct rar5* rar) +{ + uint64_t locator_flags; + + if(!read_var(a, &locator_flags, NULL)) { + return ARCHIVE_EOF; + } + + enum LOCATOR_FLAGS { + QLIST = 0x01, RECOVERY = 0x02, + }; + + if(locator_flags & QLIST) { + if(!read_var(a, &rar->qlist_offset, NULL)) { + return ARCHIVE_EOF; + } + + /* qlist is not used */ + } + + if(locator_flags & RECOVERY) { + if(!read_var(a, &rar->rr_offset, NULL)) { + return ARCHIVE_EOF; + } + + /* rr is not used */ + } + + return ARCHIVE_OK; +} + +static int parse_file_extra_hash(struct archive_read* a, struct rar5* rar, + ssize_t* extra_data_size) +{ + size_t hash_type; + size_t value_len; + + if(!read_var_sized(a, &hash_type, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) { + return ARCHIVE_EOF; + } + + enum HASH_TYPE { + BLAKE2sp = 0x00 + }; + + /* The file uses BLAKE2sp checksum algorithm instead of plain old + * CRC32. */ + if(hash_type == BLAKE2sp) { + const uint8_t* p; + const int hash_size = sizeof(rar->file.blake2sp); + + if(!read_ahead(a, hash_size, &p)) + return ARCHIVE_EOF; + + rar->file.has_blake2 = 1; + memcpy(&rar->file.blake2sp, p, hash_size); + + if(ARCHIVE_OK != consume(a, hash_size)) { + return ARCHIVE_EOF; + } + + *extra_data_size -= hash_size; + } else { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported hash type (0x%x)", (int) hash_type); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +static uint64_t time_win_to_unix(uint64_t win_time) { + const size_t ns_in_sec = 10000000; + const uint64_t sec_to_unix = 11644473600LL; + return win_time / ns_in_sec - sec_to_unix; +} + +static int parse_htime_item(struct archive_read* a, char unix_time, + uint64_t* where, ssize_t* extra_data_size) +{ + if(unix_time) { + uint32_t time_val; + if(!read_u32(a, &time_val)) + return ARCHIVE_EOF; + + *extra_data_size -= 4; + *where = (uint64_t) time_val; + } else { + uint64_t windows_time; + if(!read_u64(a, &windows_time)) + return ARCHIVE_EOF; + + *where = time_win_to_unix(windows_time); + *extra_data_size -= 8; + } + + return ARCHIVE_OK; +} + +static int parse_file_extra_version(struct archive_read* a, + struct archive_entry* e, ssize_t* extra_data_size) +{ + size_t flags = 0; + size_t version = 0; + size_t value_len = 0; + struct archive_string version_string; + struct archive_string name_utf8_string; + + /* Flags are ignored. */ + if(!read_var_sized(a, &flags, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) + return ARCHIVE_EOF; + + if(!read_var_sized(a, &version, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) + return ARCHIVE_EOF; + + /* extra_data_size should be zero here. */ + + const char* cur_filename = archive_entry_pathname_utf8(e); + if(cur_filename == NULL) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Version entry without file name"); + return ARCHIVE_FATAL; + } + + archive_string_init(&version_string); + archive_string_init(&name_utf8_string); + + /* Prepare a ;123 suffix for the filename, where '123' is the version + * value of this file. */ + archive_string_sprintf(&version_string, ";%zu", version); + + /* Build the new filename. */ + archive_strcat(&name_utf8_string, cur_filename); + archive_strcat(&name_utf8_string, version_string.s); + + /* Apply the new filename into this file's context. */ + archive_entry_update_pathname_utf8(e, name_utf8_string.s); + + /* Free buffers. */ + archive_string_free(&version_string); + archive_string_free(&name_utf8_string); + return ARCHIVE_OK; +} + +static int parse_file_extra_htime(struct archive_read* a, + struct archive_entry* e, struct rar5* rar, ssize_t* extra_data_size) +{ + char unix_time = 0; + size_t flags; + size_t value_len; + + enum HTIME_FLAGS { + IS_UNIX = 0x01, + HAS_MTIME = 0x02, + HAS_CTIME = 0x04, + HAS_ATIME = 0x08, + HAS_UNIX_NS = 0x10, + }; + + if(!read_var_sized(a, &flags, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) { + return ARCHIVE_EOF; + } + + unix_time = flags & IS_UNIX; + + if(flags & HAS_MTIME) { + parse_htime_item(a, unix_time, &rar->file.e_mtime, + extra_data_size); + archive_entry_set_mtime(e, rar->file.e_mtime, 0); + } + + if(flags & HAS_CTIME) { + parse_htime_item(a, unix_time, &rar->file.e_ctime, + extra_data_size); + archive_entry_set_ctime(e, rar->file.e_ctime, 0); + } + + if(flags & HAS_ATIME) { + parse_htime_item(a, unix_time, &rar->file.e_atime, + extra_data_size); + archive_entry_set_atime(e, rar->file.e_atime, 0); + } + + if(flags & HAS_UNIX_NS) { + if(!read_u32(a, &rar->file.e_unix_ns)) + return ARCHIVE_EOF; + + *extra_data_size -= 4; + } + + return ARCHIVE_OK; +} + +static int parse_file_extra_redir(struct archive_read* a, + struct archive_entry* e, struct rar5* rar, ssize_t* extra_data_size) +{ + uint64_t value_size = 0; + size_t target_size = 0; + char target_utf8_buf[MAX_NAME_IN_BYTES]; + const uint8_t* p; + + if(!read_var(a, &rar->file.redir_type, &value_size)) + return ARCHIVE_EOF; + if(ARCHIVE_OK != consume(a, (int64_t)value_size)) + return ARCHIVE_EOF; + *extra_data_size -= value_size; + + if(!read_var(a, &rar->file.redir_flags, &value_size)) + return ARCHIVE_EOF; + if(ARCHIVE_OK != consume(a, (int64_t)value_size)) + return ARCHIVE_EOF; + *extra_data_size -= value_size; + + if(!read_var_sized(a, &target_size, NULL)) + return ARCHIVE_EOF; + *extra_data_size -= target_size + 1; + + if(!read_ahead(a, target_size, &p)) + return ARCHIVE_EOF; + + if(target_size > (MAX_NAME_IN_CHARS - 1)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Link target is too long"); + return ARCHIVE_FATAL; + } + + if(target_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "No link target specified"); + return ARCHIVE_FATAL; + } + + memcpy(target_utf8_buf, p, target_size); + target_utf8_buf[target_size] = 0; + + if(ARCHIVE_OK != consume(a, (int64_t)target_size)) + return ARCHIVE_EOF; + + switch(rar->file.redir_type) { + case REDIR_TYPE_UNIXSYMLINK: + case REDIR_TYPE_WINSYMLINK: + archive_entry_set_filetype(e, AE_IFLNK); + archive_entry_update_symlink_utf8(e, target_utf8_buf); + if (rar->file.redir_flags & REDIR_SYMLINK_IS_DIR) { + archive_entry_set_symlink_type(e, + AE_SYMLINK_TYPE_DIRECTORY); + } else { + archive_entry_set_symlink_type(e, + AE_SYMLINK_TYPE_FILE); + } + break; + + case REDIR_TYPE_HARDLINK: + archive_entry_set_filetype(e, AE_IFREG); + archive_entry_update_hardlink_utf8(e, target_utf8_buf); + break; + + default: + /* Unknown redir type, skip it. */ + break; + } + return ARCHIVE_OK; +} + +static int parse_file_extra_owner(struct archive_read* a, + struct archive_entry* e, ssize_t* extra_data_size) +{ + uint64_t flags = 0; + uint64_t value_size = 0; + uint64_t id = 0; + size_t name_len = 0; + size_t name_size = 0; + char namebuf[OWNER_MAXNAMELEN]; + const uint8_t* p; + + if(!read_var(a, &flags, &value_size)) + return ARCHIVE_EOF; + if(ARCHIVE_OK != consume(a, (int64_t)value_size)) + return ARCHIVE_EOF; + *extra_data_size -= value_size; + + if ((flags & OWNER_USER_NAME) != 0) { + if(!read_var_sized(a, &name_size, NULL)) + return ARCHIVE_EOF; + *extra_data_size -= name_size + 1; + + if(!read_ahead(a, name_size, &p)) + return ARCHIVE_EOF; + + if (name_size >= OWNER_MAXNAMELEN) { + name_len = OWNER_MAXNAMELEN - 1; + } else { + name_len = name_size; + } + + memcpy(namebuf, p, name_len); + namebuf[name_len] = 0; + if(ARCHIVE_OK != consume(a, (int64_t)name_size)) + return ARCHIVE_EOF; + + archive_entry_set_uname(e, namebuf); + } + if ((flags & OWNER_GROUP_NAME) != 0) { + if(!read_var_sized(a, &name_size, NULL)) + return ARCHIVE_EOF; + *extra_data_size -= name_size + 1; + + if(!read_ahead(a, name_size, &p)) + return ARCHIVE_EOF; + + if (name_size >= OWNER_MAXNAMELEN) { + name_len = OWNER_MAXNAMELEN - 1; + } else { + name_len = name_size; + } + + memcpy(namebuf, p, name_len); + namebuf[name_len] = 0; + if(ARCHIVE_OK != consume(a, (int64_t)name_size)) + return ARCHIVE_EOF; + + archive_entry_set_gname(e, namebuf); + } + if ((flags & OWNER_USER_UID) != 0) { + if(!read_var(a, &id, &value_size)) + return ARCHIVE_EOF; + if(ARCHIVE_OK != consume(a, (int64_t)value_size)) + return ARCHIVE_EOF; + *extra_data_size -= value_size; + + archive_entry_set_uid(e, (la_int64_t)id); + } + if ((flags & OWNER_GROUP_GID) != 0) { + if(!read_var(a, &id, &value_size)) + return ARCHIVE_EOF; + if(ARCHIVE_OK != consume(a, (int64_t)value_size)) + return ARCHIVE_EOF; + *extra_data_size -= value_size; + + archive_entry_set_gid(e, (la_int64_t)id); + } + return ARCHIVE_OK; +} + +static int process_head_file_extra(struct archive_read* a, + struct archive_entry* e, struct rar5* rar, ssize_t extra_data_size) +{ + size_t extra_field_size; + size_t extra_field_id = 0; + int ret = ARCHIVE_FATAL; + size_t var_size; + + while(extra_data_size > 0) { + if(!read_var_sized(a, &extra_field_size, &var_size)) + return ARCHIVE_EOF; + + extra_data_size -= var_size; + if(ARCHIVE_OK != consume(a, var_size)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &extra_field_id, &var_size)) + return ARCHIVE_EOF; + + extra_data_size -= var_size; + if(ARCHIVE_OK != consume(a, var_size)) { + return ARCHIVE_EOF; + } + + switch(extra_field_id) { + case EX_HASH: + ret = parse_file_extra_hash(a, rar, + &extra_data_size); + break; + case EX_HTIME: + ret = parse_file_extra_htime(a, e, rar, + &extra_data_size); + break; + case EX_REDIR: + ret = parse_file_extra_redir(a, e, rar, + &extra_data_size); + break; + case EX_UOWNER: + ret = parse_file_extra_owner(a, e, + &extra_data_size); + break; + case EX_VERSION: + ret = parse_file_extra_version(a, e, + &extra_data_size); + break; + case EX_CRYPT: + /* fallthrough */ + case EX_SUBDATA: + /* fallthrough */ + default: + /* Skip unsupported entry. */ + return consume(a, extra_data_size); + } + } + + if(ret != ARCHIVE_OK) { + /* Attribute not implemented. */ + return ret; + } + + return ARCHIVE_OK; +} + +static int process_head_file(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + ssize_t extra_data_size = 0; + size_t data_size = 0; + size_t file_flags = 0; + size_t file_attr = 0; + size_t compression_info = 0; + size_t host_os = 0; + size_t name_size = 0; + uint64_t unpacked_size, window_size; + uint32_t mtime = 0, crc = 0; + int c_method = 0, c_version = 0; + char name_utf8_buf[MAX_NAME_IN_BYTES]; + const uint8_t* p; + + archive_entry_clear(entry); + + /* Do not reset file context if we're switching archives. */ + if(!rar->cstate.switch_multivolume) { + reset_file_context(rar); + } + + if(block_flags & HFL_EXTRA_DATA) { + size_t edata_size = 0; + if(!read_var_sized(a, &edata_size, NULL)) + return ARCHIVE_EOF; + + /* Intentional type cast from unsigned to signed. */ + extra_data_size = (ssize_t) edata_size; + } + + if(block_flags & HFL_DATA) { + if(!read_var_sized(a, &data_size, NULL)) + return ARCHIVE_EOF; + + rar->file.bytes_remaining = data_size; + } else { + rar->file.bytes_remaining = 0; + + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "no data found in file/service block"); + return ARCHIVE_FATAL; + } + + enum FILE_FLAGS { + DIRECTORY = 0x0001, UTIME = 0x0002, CRC32 = 0x0004, + UNKNOWN_UNPACKED_SIZE = 0x0008, + }; + + enum FILE_ATTRS { + ATTR_READONLY = 0x1, ATTR_HIDDEN = 0x2, ATTR_SYSTEM = 0x4, + ATTR_DIRECTORY = 0x10, + }; + + enum COMP_INFO_FLAGS { + SOLID = 0x0040, + }; + + if(!read_var_sized(a, &file_flags, NULL)) + return ARCHIVE_EOF; + + if(!read_var(a, &unpacked_size, NULL)) + return ARCHIVE_EOF; + + if(file_flags & UNKNOWN_UNPACKED_SIZE) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Files with unknown unpacked size are not supported"); + return ARCHIVE_FATAL; + } + + rar->file.dir = (uint8_t) ((file_flags & DIRECTORY) > 0); + + if(!read_var_sized(a, &file_attr, NULL)) + return ARCHIVE_EOF; + + if(file_flags & UTIME) { + if(!read_u32(a, &mtime)) + return ARCHIVE_EOF; + } + + if(file_flags & CRC32) { + if(!read_u32(a, &crc)) + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &compression_info, NULL)) + return ARCHIVE_EOF; + + c_method = (int) (compression_info >> 7) & 0x7; + c_version = (int) (compression_info & 0x3f); + + /* RAR5 seems to limit the dictionary size to 64MB. */ + window_size = (rar->file.dir > 0) ? + 0 : + g_unpack_window_size << ((compression_info >> 10) & 15); + rar->cstate.method = c_method; + rar->cstate.version = c_version + 50; + + /* Check if window_size is a sane value. Also, if the file is not + * declared as a directory, disallow window_size == 0. */ + if(window_size > (64 * 1024 * 1024) || + (rar->file.dir == 0 && window_size == 0)) + { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Declared dictionary size is not supported."); + return ARCHIVE_FATAL; + } + + /* Values up to 64M should fit into ssize_t on every + * architecture. */ + rar->cstate.window_size = (ssize_t) window_size; + + rar->file.solid = (compression_info & SOLID) > 0; + rar->file.service = 0; + + if(!read_var_sized(a, &host_os, NULL)) + return ARCHIVE_EOF; + + enum HOST_OS { + HOST_WINDOWS = 0, + HOST_UNIX = 1, + }; + + if(host_os == HOST_WINDOWS) { + /* Host OS is Windows */ + + __LA_MODE_T mode; + + if(file_attr & ATTR_DIRECTORY) { + if (file_attr & ATTR_READONLY) { + mode = 0555 | AE_IFDIR; + } else { + mode = 0755 | AE_IFDIR; + } + } else { + if (file_attr & ATTR_READONLY) { + mode = 0444 | AE_IFREG; + } else { + mode = 0644 | AE_IFREG; + } + } + + archive_entry_set_mode(entry, mode); + + if (file_attr & (ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM)) { + char *fflags_text, *ptr; + /* allocate for "rdonly,hidden,system," */ + fflags_text = malloc(22 * sizeof(char)); + if (fflags_text != NULL) { + ptr = fflags_text; + if (file_attr & ATTR_READONLY) { + strcpy(ptr, "rdonly,"); + ptr = ptr + 7; + } + if (file_attr & ATTR_HIDDEN) { + strcpy(ptr, "hidden,"); + ptr = ptr + 7; + } + if (file_attr & ATTR_SYSTEM) { + strcpy(ptr, "system,"); + ptr = ptr + 7; + } + if (ptr > fflags_text) { + /* Delete trailing comma */ + *(ptr - 1) = '\0'; + archive_entry_copy_fflags_text(entry, + fflags_text); + } + free(fflags_text); + } + } + } else if(host_os == HOST_UNIX) { + /* Host OS is Unix */ + archive_entry_set_mode(entry, (__LA_MODE_T) file_attr); + } else { + /* Unknown host OS */ + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported Host OS: 0x%x", (int) host_os); + + return ARCHIVE_FATAL; + } + + if(!read_var_sized(a, &name_size, NULL)) + return ARCHIVE_EOF; + + if(!read_ahead(a, name_size, &p)) + return ARCHIVE_EOF; + + if(name_size > (MAX_NAME_IN_CHARS - 1)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Filename is too long"); + + return ARCHIVE_FATAL; + } + + if(name_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "No filename specified"); + + return ARCHIVE_FATAL; + } + + memcpy(name_utf8_buf, p, name_size); + name_utf8_buf[name_size] = 0; + if(ARCHIVE_OK != consume(a, name_size)) { + return ARCHIVE_EOF; + } + + archive_entry_update_pathname_utf8(entry, name_utf8_buf); + + if(extra_data_size > 0) { + int ret = process_head_file_extra(a, entry, rar, + extra_data_size); + + /* Sanity check. */ + if(extra_data_size < 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "File extra data size is not zero"); + return ARCHIVE_FATAL; + } + + if(ret != ARCHIVE_OK) + return ret; + } + + if((file_flags & UNKNOWN_UNPACKED_SIZE) == 0) { + rar->file.unpacked_size = (ssize_t) unpacked_size; + if(rar->file.redir_type == REDIR_TYPE_NONE) + archive_entry_set_size(entry, unpacked_size); + } + + if(file_flags & UTIME) { + archive_entry_set_mtime(entry, (time_t) mtime, 0); + } + + if(file_flags & CRC32) { + rar->file.stored_crc32 = crc; + } + + if(!rar->cstate.switch_multivolume) { + /* Do not reinitialize unpacking state if we're switching + * archives. */ + rar->cstate.block_parsing_finished = 1; + rar->cstate.all_filters_applied = 1; + rar->cstate.initialized = 0; + } + + if(rar->generic.split_before > 0) { + /* If now we're standing on a header that has a 'split before' + * mark, it means we're standing on a 'continuation' file + * header. Signal the caller that if it wants to move to + * another file, it must call rar5_read_header() function + * again. */ + + return ARCHIVE_RETRY; + } else { + return ARCHIVE_OK; + } +} + +static int process_head_service(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + /* Process this SERVICE block the same way as FILE blocks. */ + int ret = process_head_file(a, rar, entry, block_flags); + if(ret != ARCHIVE_OK) + return ret; + + rar->file.service = 1; + + /* But skip the data part automatically. It's no use for the user + * anyway. It contains only service data, not even needed to + * properly unpack the file. */ + ret = rar5_read_data_skip(a); + if(ret != ARCHIVE_OK) + return ret; + + /* After skipping, try parsing another block automatically. */ + return ARCHIVE_RETRY; +} + +static int process_head_main(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + (void) entry; + + int ret; + size_t extra_data_size = 0; + size_t extra_field_size = 0; + size_t extra_field_id = 0; + size_t archive_flags = 0; + + if(block_flags & HFL_EXTRA_DATA) { + if(!read_var_sized(a, &extra_data_size, NULL)) + return ARCHIVE_EOF; + } else { + extra_data_size = 0; + } + + if(!read_var_sized(a, &archive_flags, NULL)) { + return ARCHIVE_EOF; + } + + enum MAIN_FLAGS { + VOLUME = 0x0001, /* multi-volume archive */ + VOLUME_NUMBER = 0x0002, /* volume number, first vol doesn't + * have it */ + SOLID = 0x0004, /* solid archive */ + PROTECT = 0x0008, /* contains Recovery info */ + LOCK = 0x0010, /* readonly flag, not used */ + }; + + rar->main.volume = (archive_flags & VOLUME) > 0; + rar->main.solid = (archive_flags & SOLID) > 0; + + if(archive_flags & VOLUME_NUMBER) { + size_t v = 0; + if(!read_var_sized(a, &v, NULL)) { + return ARCHIVE_EOF; + } + + if (v > UINT_MAX) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Invalid volume number"); + return ARCHIVE_FATAL; + } + + rar->main.vol_no = (unsigned int) v; + } else { + rar->main.vol_no = 0; + } + + if(rar->vol.expected_vol_no > 0 && + rar->main.vol_no != rar->vol.expected_vol_no) + { + /* Returning EOF instead of FATAL because of strange + * libarchive behavior. When opening multiple files via + * archive_read_open_filenames(), after reading up the whole + * last file, the __archive_read_ahead function wraps up to + * the first archive instead of returning EOF. */ + return ARCHIVE_EOF; + } + + if(extra_data_size == 0) { + /* Early return. */ + return ARCHIVE_OK; + } + + if(!read_var_sized(a, &extra_field_size, NULL)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &extra_field_id, NULL)) { + return ARCHIVE_EOF; + } + + if(extra_field_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Invalid extra field size"); + return ARCHIVE_FATAL; + } + + enum MAIN_EXTRA { + // Just one attribute here. + LOCATOR = 0x01, + }; + + switch(extra_field_id) { + case LOCATOR: + ret = process_main_locator_extra_block(a, rar); + if(ret != ARCHIVE_OK) { + /* Error while parsing main locator extra + * block. */ + return ret; + } + + break; + default: + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported extra type (0x%x)", + (int) extra_field_id); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +static int skip_unprocessed_bytes(struct archive_read* a) { + struct rar5* rar = get_context(a); + int ret; + + if(rar->file.bytes_remaining) { + /* Use different skipping method in block merging mode than in + * normal mode. If merge mode is active, rar5_read_data_skip + * can't be used, because it could allow recursive use of + * merge_block() * function, and this function doesn't support + * recursive use. */ + if(rar->merge_mode) { + /* Discard whole merged block. This is valid in solid + * mode as well, because the code will discard blocks + * only if those blocks are safe to discard (i.e. + * they're not FILE blocks). */ + ret = consume(a, rar->file.bytes_remaining); + if(ret != ARCHIVE_OK) { + return ret; + } + rar->file.bytes_remaining = 0; + } else { + /* If we're not in merge mode, use safe skipping code. + * This will ensure we'll handle solid archives + * properly. */ + ret = rar5_read_data_skip(a); + if(ret != ARCHIVE_OK) { + return ret; + } + } + } + + return ARCHIVE_OK; +} + +static int scan_for_signature(struct archive_read* a); + +/* Base block processing function. A 'base block' is a RARv5 header block + * that tells the reader what kind of data is stored inside the block. + * + * From the birds-eye view a RAR file looks file this: + * + * <magic><base_block_1><base_block_2>...<base_block_n> + * + * There are a few types of base blocks. Those types are specified inside + * the 'switch' statement in this function. For example purposes, I'll write + * how a standard RARv5 file could look like here: + * + * <magic><MAIN><FILE><FILE><FILE><SERVICE><ENDARC> + * + * The structure above could describe an archive file with 3 files in it, + * one service "QuickOpen" block (that is ignored by this parser), and an + * end of file base block marker. + * + * If the file is stored in multiple archive files ("multiarchive"), it might + * look like this: + * + * .part01.rar: <magic><MAIN><FILE><ENDARC> + * .part02.rar: <magic><MAIN><FILE><ENDARC> + * .part03.rar: <magic><MAIN><FILE><ENDARC> + * + * This example could describe 3 RAR files that contain ONE archived file. + * Or it could describe 3 RAR files that contain 3 different files. Or 3 + * RAR files than contain 2 files. It all depends what metadata is stored in + * the headers of <FILE> blocks. + * + * Each <FILE> block contains info about its size, the name of the file it's + * storing inside, and whether this FILE block is a continuation block of + * previous archive ('split before'), and is this FILE block should be + * continued in another archive ('split after'). By parsing the 'split before' + * and 'split after' flags, we're able to tell if multiple <FILE> base blocks + * are describing one file, or multiple files (with the same filename, for + * example). + * + * One thing to note is that if we're parsing the first <FILE> block, and + * we see 'split after' flag, then we need to jump over to another <FILE> + * block to be able to decompress rest of the data. To do this, we need + * to skip the <ENDARC> block, then switch to another file, then skip the + * <magic> block, <MAIN> block, and then we're standing on the proper + * <FILE> block. + */ + +static int process_base_block(struct archive_read* a, + struct archive_entry* entry) +{ + struct rar5* rar = get_context(a); + uint32_t hdr_crc, computed_crc; + size_t raw_hdr_size = 0, hdr_size_len, hdr_size; + size_t header_id = 0; + size_t header_flags = 0; + const uint8_t* p; + int ret; + + /* Skip any unprocessed data for this file. */ + ret = skip_unprocessed_bytes(a); + if(ret != ARCHIVE_OK) + return ret; + + /* Read the expected CRC32 checksum. */ + if(!read_u32(a, &hdr_crc)) { + return ARCHIVE_EOF; + } + + /* Read header size. */ + if(!read_var_sized(a, &raw_hdr_size, &hdr_size_len)) { + return ARCHIVE_EOF; + } + + /* Sanity check, maximum header size for RAR5 is 2MB. */ + if(raw_hdr_size > (2 * 1024 * 1024)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Base block header is too large"); + + return ARCHIVE_FATAL; + } + + hdr_size = raw_hdr_size + hdr_size_len; + + /* Read the whole header data into memory, maximum memory use here is + * 2MB. */ + if(!read_ahead(a, hdr_size, &p)) { + return ARCHIVE_EOF; + } + + /* Verify the CRC32 of the header data. */ + computed_crc = (uint32_t) crc32(0, p, (int) hdr_size); + if(computed_crc != hdr_crc) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Header CRC error"); + + return ARCHIVE_FATAL; + } + + /* If the checksum is OK, we proceed with parsing. */ + if(ARCHIVE_OK != consume(a, hdr_size_len)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &header_id, NULL)) + return ARCHIVE_EOF; + + if(!read_var_sized(a, &header_flags, NULL)) + return ARCHIVE_EOF; + + rar->generic.split_after = (header_flags & HFL_SPLIT_AFTER) > 0; + rar->generic.split_before = (header_flags & HFL_SPLIT_BEFORE) > 0; + rar->generic.size = (int)hdr_size; + rar->generic.last_header_id = (int)header_id; + rar->main.endarc = 0; + + /* Those are possible header ids in RARv5. */ + enum HEADER_TYPE { + HEAD_MARK = 0x00, HEAD_MAIN = 0x01, HEAD_FILE = 0x02, + HEAD_SERVICE = 0x03, HEAD_CRYPT = 0x04, HEAD_ENDARC = 0x05, + HEAD_UNKNOWN = 0xff, + }; + + switch(header_id) { + case HEAD_MAIN: + ret = process_head_main(a, rar, entry, header_flags); + + /* Main header doesn't have any files in it, so it's + * pointless to return to the caller. Retry to next + * header, which should be HEAD_FILE/HEAD_SERVICE. */ + if(ret == ARCHIVE_OK) + return ARCHIVE_RETRY; + + return ret; + case HEAD_SERVICE: + ret = process_head_service(a, rar, entry, header_flags); + return ret; + case HEAD_FILE: + ret = process_head_file(a, rar, entry, header_flags); + return ret; + case HEAD_CRYPT: + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Encryption is not supported"); + return ARCHIVE_FATAL; + case HEAD_ENDARC: + rar->main.endarc = 1; + + /* After encountering an end of file marker, we need + * to take into consideration if this archive is + * continued in another file (i.e. is it part01.rar: + * is there a part02.rar?) */ + if(rar->main.volume) { + /* In case there is part02.rar, position the + * read pointer in a proper place, so we can + * resume parsing. */ + ret = scan_for_signature(a); + if(ret == ARCHIVE_FATAL) { + return ARCHIVE_EOF; + } else { + if(rar->vol.expected_vol_no == + UINT_MAX) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Header error"); + return ARCHIVE_FATAL; + } + + rar->vol.expected_vol_no = + rar->main.vol_no + 1; + return ARCHIVE_OK; + } + } else { + return ARCHIVE_EOF; + } + case HEAD_MARK: + return ARCHIVE_EOF; + default: + if((header_flags & HFL_SKIP_IF_UNKNOWN) == 0) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Header type error"); + return ARCHIVE_FATAL; + } else { + /* If the block is marked as 'skip if unknown', + * do as the flag says: skip the block + * instead on failing on it. */ + return ARCHIVE_RETRY; + } + } + +#if !defined WIN32 + // Not reached. + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Internal unpacker error"); + return ARCHIVE_FATAL; +#endif +} + +static int skip_base_block(struct archive_read* a) { + int ret; + struct rar5* rar = get_context(a); + + /* Create a new local archive_entry structure that will be operated on + * by header reader; operations on this archive_entry will be discarded. + */ + struct archive_entry* entry = archive_entry_new(); + ret = process_base_block(a, entry); + + /* Discard operations on this archive_entry structure. */ + archive_entry_free(entry); + if(ret == ARCHIVE_FATAL) + return ret; + + if(rar->generic.last_header_id == 2 && rar->generic.split_before > 0) + return ARCHIVE_OK; + + if(ret == ARCHIVE_OK) + return ARCHIVE_RETRY; + else + return ret; +} + +static int rar5_read_header(struct archive_read *a, + struct archive_entry *entry) +{ + struct rar5* rar = get_context(a); + int ret; + + if(rar->header_initialized == 0) { + init_header(a); + rar->header_initialized = 1; + } + + if(rar->skipped_magic == 0) { + if(ARCHIVE_OK != consume(a, rar5_signature_size)) { + return ARCHIVE_EOF; + } + + rar->skipped_magic = 1; + } + + do { + ret = process_base_block(a, entry); + } while(ret == ARCHIVE_RETRY || + (rar->main.endarc > 0 && ret == ARCHIVE_OK)); + + return ret; +} + +static void init_unpack(struct rar5* rar) { + rar->file.calculated_crc32 = 0; + if (rar->cstate.window_size) + rar->cstate.window_mask = rar->cstate.window_size - 1; + else + rar->cstate.window_mask = 0; + + free(rar->cstate.window_buf); + free(rar->cstate.filtered_buf); + + if(rar->cstate.window_size > 0) { + rar->cstate.window_buf = calloc(1, rar->cstate.window_size); + rar->cstate.filtered_buf = calloc(1, rar->cstate.window_size); + } else { + rar->cstate.window_buf = NULL; + rar->cstate.filtered_buf = NULL; + } + + rar->cstate.write_ptr = 0; + rar->cstate.last_write_ptr = 0; + + memset(&rar->cstate.bd, 0, sizeof(rar->cstate.bd)); + memset(&rar->cstate.ld, 0, sizeof(rar->cstate.ld)); + memset(&rar->cstate.dd, 0, sizeof(rar->cstate.dd)); + memset(&rar->cstate.ldd, 0, sizeof(rar->cstate.ldd)); + memset(&rar->cstate.rd, 0, sizeof(rar->cstate.rd)); +} + +static void update_crc(struct rar5* rar, const uint8_t* p, size_t to_read) { + int verify_crc; + + if(rar->skip_mode) { +#if defined CHECK_CRC_ON_SOLID_SKIP + verify_crc = 1; +#else + verify_crc = 0; +#endif + } else + verify_crc = 1; + + if(verify_crc) { + /* Don't update CRC32 if the file doesn't have the + * `stored_crc32` info filled in. */ + if(rar->file.stored_crc32 > 0) { + rar->file.calculated_crc32 = + crc32(rar->file.calculated_crc32, p, to_read); + } + + /* Check if the file uses an optional BLAKE2sp checksum + * algorithm. */ + if(rar->file.has_blake2 > 0) { + /* Return value of the `update` function is always 0, + * so we can explicitly ignore it here. */ + (void) blake2sp_update(&rar->file.b2state, p, to_read); + } + } +} + +static int create_decode_tables(uint8_t* bit_length, + struct decode_table* table, int size) +{ + int code, upper_limit = 0, i, lc[16]; + uint32_t decode_pos_clone[rar5_countof(table->decode_pos)]; + ssize_t cur_len, quick_data_size; + + memset(&lc, 0, sizeof(lc)); + memset(table->decode_num, 0, sizeof(table->decode_num)); + table->size = size; + table->quick_bits = size == HUFF_NC ? 10 : 7; + + for(i = 0; i < size; i++) { + lc[bit_length[i] & 15]++; + } + + lc[0] = 0; + table->decode_pos[0] = 0; + table->decode_len[0] = 0; + + for(i = 1; i < 16; i++) { + upper_limit += lc[i]; + + table->decode_len[i] = upper_limit << (16 - i); + table->decode_pos[i] = table->decode_pos[i - 1] + lc[i - 1]; + + upper_limit <<= 1; + } + + memcpy(decode_pos_clone, table->decode_pos, sizeof(decode_pos_clone)); + + for(i = 0; i < size; i++) { + uint8_t clen = bit_length[i] & 15; + if(clen > 0) { + int last_pos = decode_pos_clone[clen]; + table->decode_num[last_pos] = i; + decode_pos_clone[clen]++; + } + } + + quick_data_size = (int64_t)1 << table->quick_bits; + cur_len = 1; + for(code = 0; code < quick_data_size; code++) { + int bit_field = code << (16 - table->quick_bits); + int dist, pos; + + while(cur_len < rar5_countof(table->decode_len) && + bit_field >= table->decode_len[cur_len]) { + cur_len++; + } + + table->quick_len[code] = (uint8_t) cur_len; + + dist = bit_field - table->decode_len[cur_len - 1]; + dist >>= (16 - cur_len); + + pos = table->decode_pos[cur_len & 15] + dist; + if(cur_len < rar5_countof(table->decode_pos) && pos < size) { + table->quick_num[code] = table->decode_num[pos]; + } else { + table->quick_num[code] = 0; + } + } + + return ARCHIVE_OK; +} + +static int decode_number(struct archive_read* a, struct decode_table* table, + const uint8_t* p, uint16_t* num) +{ + int i, bits, dist; + uint16_t bitfield; + uint32_t pos; + struct rar5* rar = get_context(a); + + if(ARCHIVE_OK != read_bits_16(rar, p, &bitfield)) { + return ARCHIVE_EOF; + } + + bitfield &= 0xfffe; + + if(bitfield < table->decode_len[table->quick_bits]) { + int code = bitfield >> (16 - table->quick_bits); + skip_bits(rar, table->quick_len[code]); + *num = table->quick_num[code]; + return ARCHIVE_OK; + } + + bits = 15; + + for(i = table->quick_bits + 1; i < 15; i++) { + if(bitfield < table->decode_len[i]) { + bits = i; + break; + } + } + + skip_bits(rar, bits); + + dist = bitfield - table->decode_len[bits - 1]; + dist >>= (16 - bits); + pos = table->decode_pos[bits] + dist; + + if(pos >= table->size) + pos = 0; + + *num = table->decode_num[pos]; + return ARCHIVE_OK; +} + +/* Reads and parses Huffman tables from the beginning of the block. */ +static int parse_tables(struct archive_read* a, struct rar5* rar, + const uint8_t* p) +{ + int ret, value, i, w, idx = 0; + uint8_t bit_length[HUFF_BC], + table[HUFF_TABLE_SIZE], + nibble_mask = 0xF0, + nibble_shift = 4; + + enum { ESCAPE = 15 }; + + /* The data for table generation is compressed using a simple RLE-like + * algorithm when storing zeroes, so we need to unpack it first. */ + for(w = 0, i = 0; w < HUFF_BC;) { + if(i >= rar->cstate.cur_block_size) { + /* Truncated data, can't continue. */ + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Truncated data in huffman tables"); + return ARCHIVE_FATAL; + } + + value = (p[i] & nibble_mask) >> nibble_shift; + + if(nibble_mask == 0x0F) + ++i; + + nibble_mask ^= 0xFF; + nibble_shift ^= 4; + + /* Values smaller than 15 is data, so we write it directly. + * Value 15 is a flag telling us that we need to unpack more + * bytes. */ + if(value == ESCAPE) { + value = (p[i] & nibble_mask) >> nibble_shift; + if(nibble_mask == 0x0F) + ++i; + nibble_mask ^= 0xFF; + nibble_shift ^= 4; + + if(value == 0) { + /* We sometimes need to write the actual value + * of 15, so this case handles that. */ + bit_length[w++] = ESCAPE; + } else { + int k; + + /* Fill zeroes. */ + for(k = 0; (k < value + 2) && (w < HUFF_BC); + k++) { + bit_length[w++] = 0; + } + } + } else { + bit_length[w++] = value; + } + } + + rar->bits.in_addr = i; + rar->bits.bit_addr = nibble_shift ^ 4; + + ret = create_decode_tables(bit_length, &rar->cstate.bd, HUFF_BC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Decoding huffman tables failed"); + return ARCHIVE_FATAL; + } + + for(i = 0; i < HUFF_TABLE_SIZE;) { + uint16_t num; + + if((rar->bits.in_addr + 6) >= rar->cstate.cur_block_size) { + /* Truncated data, can't continue. */ + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Truncated data in huffman tables (#2)"); + return ARCHIVE_FATAL; + } + + ret = decode_number(a, &rar->cstate.bd, p, &num); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Decoding huffman tables failed"); + return ARCHIVE_FATAL; + } + + if(num < 16) { + /* 0..15: store directly */ + table[i] = (uint8_t) num; + i++; + continue; + } + + if(num < 18) { + /* 16..17: repeat previous code */ + uint16_t n; + if(ARCHIVE_OK != read_bits_16(rar, p, &n)) + return ARCHIVE_EOF; + + if(num == 16) { + n >>= 13; + n += 3; + skip_bits(rar, 3); + } else { + n >>= 9; + n += 11; + skip_bits(rar, 7); + } + + if(i > 0) { + while(n-- > 0 && i < HUFF_TABLE_SIZE) { + table[i] = table[i - 1]; + i++; + } + } else { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Unexpected error when decoding " + "huffman tables"); + return ARCHIVE_FATAL; + } + + continue; + } + + /* other codes: fill with zeroes `n` times */ + uint16_t n; + if(ARCHIVE_OK != read_bits_16(rar, p, &n)) + return ARCHIVE_EOF; + + if(num == 18) { + n >>= 13; + n += 3; + skip_bits(rar, 3); + } else { + n >>= 9; + n += 11; + skip_bits(rar, 7); + } + + while(n-- > 0 && i < HUFF_TABLE_SIZE) + table[i++] = 0; + } + + ret = create_decode_tables(&table[idx], &rar->cstate.ld, HUFF_NC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create literal table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_NC; + + ret = create_decode_tables(&table[idx], &rar->cstate.dd, HUFF_DC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create distance table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_DC; + + ret = create_decode_tables(&table[idx], &rar->cstate.ldd, HUFF_LDC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create lower bits of distances table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_LDC; + + ret = create_decode_tables(&table[idx], &rar->cstate.rd, HUFF_RC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create repeating distances table"); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Parses the block header, verifies its CRC byte, and saves the header + * fields inside the `hdr` pointer. */ +static int parse_block_header(struct archive_read* a, const uint8_t* p, + ssize_t* block_size, struct compressed_block_header* hdr) +{ + memcpy(hdr, p, sizeof(struct compressed_block_header)); + + if(bf_byte_count(hdr) > 2) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported block header size (was %d, max is 2)", + bf_byte_count(hdr)); + return ARCHIVE_FATAL; + } + + /* This should probably use bit reader interface in order to be more + * future-proof. */ + *block_size = 0; + switch(bf_byte_count(hdr)) { + /* 1-byte block size */ + case 0: + *block_size = *(const uint8_t*) &p[2]; + break; + + /* 2-byte block size */ + case 1: + *block_size = archive_le16dec(&p[2]); + break; + + /* 3-byte block size */ + case 2: + *block_size = archive_le32dec(&p[2]); + *block_size &= 0x00FFFFFF; + break; + + /* Other block sizes are not supported. This case is not + * reached, because we have an 'if' guard before the switch + * that makes sure of it. */ + default: + return ARCHIVE_FATAL; + } + + /* Verify the block header checksum. 0x5A is a magic value and is + * always * constant. */ + uint8_t calculated_cksum = 0x5A + ^ (uint8_t) hdr->block_flags_u8 + ^ (uint8_t) *block_size + ^ (uint8_t) (*block_size >> 8) + ^ (uint8_t) (*block_size >> 16); + + if(calculated_cksum != hdr->block_cksum) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Block checksum error: got 0x%x, expected 0x%x", + hdr->block_cksum, calculated_cksum); + + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Convenience function used during filter processing. */ +static int parse_filter_data(struct rar5* rar, const uint8_t* p, + uint32_t* filter_data) +{ + int i, bytes; + uint32_t data = 0; + + if(ARCHIVE_OK != read_consume_bits(rar, p, 2, &bytes)) + return ARCHIVE_EOF; + + bytes++; + + for(i = 0; i < bytes; i++) { + uint16_t byte; + + if(ARCHIVE_OK != read_bits_16(rar, p, &byte)) { + return ARCHIVE_EOF; + } + + /* Cast to uint32_t will ensure the shift operation will not + * produce undefined result. */ + data += ((uint32_t) byte >> 8) << (i * 8); + skip_bits(rar, 8); + } + + *filter_data = data; + return ARCHIVE_OK; +} + +/* Function is used during sanity checking. */ +static int is_valid_filter_block_start(struct rar5* rar, + uint32_t start) +{ + const int64_t block_start = (ssize_t) start + rar->cstate.write_ptr; + const int64_t last_bs = rar->cstate.last_block_start; + const ssize_t last_bl = rar->cstate.last_block_length; + + if(last_bs == 0 || last_bl == 0) { + /* We didn't have any filters yet, so accept this offset. */ + return 1; + } + + if(block_start >= last_bs + last_bl) { + /* Current offset is bigger than last block's end offset, so + * accept current offset. */ + return 1; + } + + /* Any other case is not a normal situation and we should fail. */ + return 0; +} + +/* The function will create a new filter, read its parameters from the input + * stream and add it to the filter collection. */ +static int parse_filter(struct archive_read* ar, const uint8_t* p) { + uint32_t block_start, block_length; + uint16_t filter_type; + struct rar5* rar = get_context(ar); + + /* Read the parameters from the input stream. */ + if(ARCHIVE_OK != parse_filter_data(rar, p, &block_start)) + return ARCHIVE_EOF; + + if(ARCHIVE_OK != parse_filter_data(rar, p, &block_length)) + return ARCHIVE_EOF; + + if(ARCHIVE_OK != read_bits_16(rar, p, &filter_type)) + return ARCHIVE_EOF; + + filter_type >>= 13; + skip_bits(rar, 3); + + /* Perform some sanity checks on this filter parameters. Note that we + * allow only DELTA, E8/E9 and ARM filters here, because rest of + * filters are not used in RARv5. */ + + if(block_length < 4 || + block_length > 0x400000 || + filter_type > FILTER_ARM || + !is_valid_filter_block_start(rar, block_start)) + { + archive_set_error(&ar->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Invalid filter encountered"); + return ARCHIVE_FATAL; + } + + /* Allocate a new filter. */ + struct filter_info* filt = add_new_filter(rar); + if(filt == NULL) { + archive_set_error(&ar->archive, ENOMEM, + "Can't allocate memory for a filter descriptor."); + return ARCHIVE_FATAL; + } + + filt->type = filter_type; + filt->block_start = rar->cstate.write_ptr + block_start; + filt->block_length = block_length; + + rar->cstate.last_block_start = filt->block_start; + rar->cstate.last_block_length = filt->block_length; + + /* Read some more data in case this is a DELTA filter. Other filter + * types don't require any additional data over what was already + * read. */ + if(filter_type == FILTER_DELTA) { + int channels; + + if(ARCHIVE_OK != read_consume_bits(rar, p, 5, &channels)) + return ARCHIVE_EOF; + + filt->channels = channels + 1; + } + + return ARCHIVE_OK; +} + +static int decode_code_length(struct rar5* rar, const uint8_t* p, + uint16_t code) +{ + int lbits, length = 2; + if(code < 8) { + lbits = 0; + length += code; + } else { + lbits = code / 4 - 1; + length += (4 | (code & 3)) << lbits; + } + + if(lbits > 0) { + int add; + + if(ARCHIVE_OK != read_consume_bits(rar, p, lbits, &add)) + return -1; + + length += add; + } + + return length; +} + +static int copy_string(struct archive_read* a, int len, int dist) { + struct rar5* rar = get_context(a); + const uint64_t cmask = rar->cstate.window_mask; + const uint64_t write_ptr = rar->cstate.write_ptr + + rar->cstate.solid_offset; + int i; + + if (rar->cstate.window_buf == NULL) + return ARCHIVE_FATAL; + + /* The unpacker spends most of the time in this function. It would be + * a good idea to introduce some optimizations here. + * + * Just remember that this loop treats buffers that overlap differently + * than buffers that do not overlap. This is why a simple memcpy(3) + * call will not be enough. */ + + for(i = 0; i < len; i++) { + const ssize_t write_idx = (write_ptr + i) & cmask; + const ssize_t read_idx = (write_ptr + i - dist) & cmask; + rar->cstate.window_buf[write_idx] = + rar->cstate.window_buf[read_idx]; + } + + rar->cstate.write_ptr += len; + return ARCHIVE_OK; +} + +static int do_uncompress_block(struct archive_read* a, const uint8_t* p) { + struct rar5* rar = get_context(a); + uint16_t num; + int ret; + + const uint64_t cmask = rar->cstate.window_mask; + const struct compressed_block_header* hdr = &rar->last_block_hdr; + const uint8_t bit_size = 1 + bf_bit_size(hdr); + + while(1) { + if(rar->cstate.write_ptr - rar->cstate.last_write_ptr > + (rar->cstate.window_size >> 1)) { + /* Don't allow growing data by more than half of the + * window size at a time. In such case, break the loop; + * next call to this function will continue processing + * from this moment. */ + break; + } + + if(rar->bits.in_addr > rar->cstate.cur_block_size - 1 || + (rar->bits.in_addr == rar->cstate.cur_block_size - 1 && + rar->bits.bit_addr >= bit_size)) + { + /* If the program counter is here, it means the + * function has finished processing the block. */ + rar->cstate.block_parsing_finished = 1; + break; + } + + /* Decode the next literal. */ + if(ARCHIVE_OK != decode_number(a, &rar->cstate.ld, p, &num)) { + return ARCHIVE_EOF; + } + + /* Num holds a decompression literal, or 'command code'. + * + * - Values lower than 256 are just bytes. Those codes + * can be stored in the output buffer directly. + * + * - Code 256 defines a new filter, which is later used to + * ransform the data block accordingly to the filter type. + * The data block needs to be fully uncompressed first. + * + * - Code bigger than 257 and smaller than 262 define + * a repetition pattern that should be copied from + * an already uncompressed chunk of data. + */ + + if(num < 256) { + /* Directly store the byte. */ + int64_t write_idx = rar->cstate.solid_offset + + rar->cstate.write_ptr++; + + rar->cstate.window_buf[write_idx & cmask] = + (uint8_t) num; + continue; + } else if(num >= 262) { + uint16_t dist_slot; + int len = decode_code_length(rar, p, num - 262), + dbits, + dist = 1; + + if(len == -1) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the code length"); + + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != decode_number(a, &rar->cstate.dd, p, + &dist_slot)) + { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the distance slot"); + + return ARCHIVE_FATAL; + } + + if(dist_slot < 4) { + dbits = 0; + dist += dist_slot; + } else { + dbits = dist_slot / 2 - 1; + + /* Cast to uint32_t will make sure the shift + * left operation won't produce undefined + * result. Then, the uint32_t type will + * be implicitly casted to int. */ + dist += (uint32_t) (2 | + (dist_slot & 1)) << dbits; + } + + if(dbits > 0) { + if(dbits >= 4) { + uint32_t add = 0; + uint16_t low_dist; + + if(dbits > 4) { + if(ARCHIVE_OK != read_bits_32( + rar, p, &add)) { + /* Return EOF if we + * can't read more + * data. */ + return ARCHIVE_EOF; + } + + skip_bits(rar, dbits - 4); + add = (add >> ( + 36 - dbits)) << 4; + dist += add; + } + + if(ARCHIVE_OK != decode_number(a, + &rar->cstate.ldd, p, &low_dist)) + { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the " + "distance slot"); + + return ARCHIVE_FATAL; + } + + if(dist >= INT_MAX - low_dist - 1) { + /* This only happens in + * invalid archives. */ + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Distance pointer " + "overflow"); + return ARCHIVE_FATAL; + } + + dist += low_dist; + } else { + /* dbits is one of [0,1,2,3] */ + int add; + + if(ARCHIVE_OK != read_consume_bits(rar, + p, dbits, &add)) { + /* Return EOF if we can't read + * more data. */ + return ARCHIVE_EOF; + } + + dist += add; + } + } + + if(dist > 0x100) { + len++; + + if(dist > 0x2000) { + len++; + + if(dist > 0x40000) { + len++; + } + } + } + + dist_cache_push(rar, dist); + rar->cstate.last_len = len; + + if(ARCHIVE_OK != copy_string(a, len, dist)) + return ARCHIVE_FATAL; + + continue; + } else if(num == 256) { + /* Create a filter. */ + ret = parse_filter(a, p); + if(ret != ARCHIVE_OK) + return ret; + + continue; + } else if(num == 257) { + if(rar->cstate.last_len != 0) { + if(ARCHIVE_OK != copy_string(a, + rar->cstate.last_len, + rar->cstate.dist_cache[0])) + { + return ARCHIVE_FATAL; + } + } + + continue; + } else if(num < 262) { + const int idx = num - 258; + const int dist = dist_cache_touch(rar, idx); + + uint16_t len_slot; + int len; + + if(ARCHIVE_OK != decode_number(a, &rar->cstate.rd, p, + &len_slot)) { + return ARCHIVE_FATAL; + } + + len = decode_code_length(rar, p, len_slot); + rar->cstate.last_len = len; + + if(ARCHIVE_OK != copy_string(a, len, dist)) + return ARCHIVE_FATAL; + + continue; + } + + /* The program counter shouldn't reach here. */ + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported block code: 0x%x", num); + + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Binary search for the RARv5 signature. */ +static int scan_for_signature(struct archive_read* a) { + const uint8_t* p; + const int chunk_size = 512; + ssize_t i; + + /* If we're here, it means we're on an 'unknown territory' data. + * There's no indication what kind of data we're reading here. + * It could be some text comment, any kind of binary data, + * digital sign, dragons, etc. + * + * We want to find a valid RARv5 magic header inside this unknown + * data. */ + + /* Is it possible in libarchive to just skip everything until the + * end of the file? If so, it would be a better approach than the + * current implementation of this function. */ + + while(1) { + if(!read_ahead(a, chunk_size, &p)) + return ARCHIVE_EOF; + + for(i = 0; i < chunk_size - rar5_signature_size; i++) { + if(memcmp(&p[i], rar5_signature, + rar5_signature_size) == 0) { + /* Consume the number of bytes we've used to + * search for the signature, as well as the + * number of bytes used by the signature + * itself. After this we should be standing + * on a valid base block header. */ + (void) consume(a, i + rar5_signature_size); + return ARCHIVE_OK; + } + } + + consume(a, chunk_size); + } + + return ARCHIVE_FATAL; +} + +/* This function will switch the multivolume archive file to another file, + * i.e. from part03 to part 04. */ +static int advance_multivolume(struct archive_read* a) { + int lret; + struct rar5* rar = get_context(a); + + /* A small state machine that will skip unnecessary data, needed to + * switch from one multivolume to another. Such skipping is needed if + * we want to be an stream-oriented (instead of file-oriented) + * unpacker. + * + * The state machine starts with `rar->main.endarc` == 0. It also + * assumes that current stream pointer points to some base block + * header. + * + * The `endarc` field is being set when the base block parsing + * function encounters the 'end of archive' marker. + */ + + while(1) { + if(rar->main.endarc == 1) { + int looping = 1; + + rar->main.endarc = 0; + + while(looping) { + lret = skip_base_block(a); + switch(lret) { + case ARCHIVE_RETRY: + /* Continue looping. */ + break; + case ARCHIVE_OK: + /* Break loop. */ + looping = 0; + break; + default: + /* Forward any errors to the + * caller. */ + return lret; + } + } + + break; + } else { + /* Skip current base block. In order to properly skip + * it, we really need to simply parse it and discard + * the results. */ + + lret = skip_base_block(a); + if(lret == ARCHIVE_FATAL || lret == ARCHIVE_FAILED) + return lret; + + /* The `skip_base_block` function tells us if we + * should continue with skipping, or we should stop + * skipping. We're trying to skip everything up to + * a base FILE block. */ + + if(lret != ARCHIVE_RETRY) { + /* If there was an error during skipping, or we + * have just skipped a FILE base block... */ + + if(rar->main.endarc == 0) { + return lret; + } else { + continue; + } + } + } + } + + return ARCHIVE_OK; +} + +/* Merges the partial block from the first multivolume archive file, and + * partial block from the second multivolume archive file. The result is + * a chunk of memory containing the whole block, and the stream pointer + * is advanced to the next block in the second multivolume archive file. */ +static int merge_block(struct archive_read* a, ssize_t block_size, + const uint8_t** p) +{ + struct rar5* rar = get_context(a); + ssize_t cur_block_size, partial_offset = 0; + const uint8_t* lp; + int ret; + + if(rar->merge_mode) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Recursive merge is not allowed"); + + return ARCHIVE_FATAL; + } + + /* Set a flag that we're in the switching mode. */ + rar->cstate.switch_multivolume = 1; + + /* Reallocate the memory which will hold the whole block. */ + if(rar->vol.push_buf) + free((void*) rar->vol.push_buf); + + /* Increasing the allocation block by 8 is due to bit reading functions, + * which are using additional 2 or 4 bytes. Allocating the block size + * by exact value would make bit reader perform reads from invalid + * memory block when reading the last byte from the buffer. */ + rar->vol.push_buf = malloc(block_size + 8); + if(!rar->vol.push_buf) { + archive_set_error(&a->archive, ENOMEM, + "Can't allocate memory for a merge block buffer."); + return ARCHIVE_FATAL; + } + + /* Valgrind complains if the extension block for bit reader is not + * initialized, so initialize it. */ + memset(&rar->vol.push_buf[block_size], 0, 8); + + /* A single block can span across multiple multivolume archive files, + * so we use a loop here. This loop will consume enough multivolume + * archive files until the whole block is read. */ + + while(1) { + /* Get the size of current block chunk in this multivolume + * archive file and read it. */ + cur_block_size = rar5_min(rar->file.bytes_remaining, + block_size - partial_offset); + + if(cur_block_size == 0) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Encountered block size == 0 during block merge"); + return ARCHIVE_FATAL; + } + + if(!read_ahead(a, cur_block_size, &lp)) + return ARCHIVE_EOF; + + /* Sanity check; there should never be a situation where this + * function reads more data than the block's size. */ + if(partial_offset + cur_block_size > block_size) { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Consumed too much data when merging blocks."); + return ARCHIVE_FATAL; + } + + /* Merge previous block chunk with current block chunk, + * or create first block chunk if this is our first + * iteration. */ + memcpy(&rar->vol.push_buf[partial_offset], lp, cur_block_size); + + /* Advance the stream read pointer by this block chunk size. */ + if(ARCHIVE_OK != consume(a, cur_block_size)) + return ARCHIVE_EOF; + + /* Update the pointers. `partial_offset` contains information + * about the sum of merged block chunks. */ + partial_offset += cur_block_size; + rar->file.bytes_remaining -= cur_block_size; + + /* If `partial_offset` is the same as `block_size`, this means + * we've merged all block chunks and we have a valid full + * block. */ + if(partial_offset == block_size) { + break; + } + + /* If we don't have any bytes to read, this means we should + * switch to another multivolume archive file. */ + if(rar->file.bytes_remaining == 0) { + rar->merge_mode++; + ret = advance_multivolume(a); + rar->merge_mode--; + if(ret != ARCHIVE_OK) { + return ret; + } + } + } + + *p = rar->vol.push_buf; + + /* If we're here, we can resume unpacking by processing the block + * pointed to by the `*p` memory pointer. */ + + return ARCHIVE_OK; +} + +static int process_block(struct archive_read* a) { + const uint8_t* p; + struct rar5* rar = get_context(a); + int ret; + + /* If we don't have any data to be processed, this most probably means + * we need to switch to the next volume. */ + if(rar->main.volume && rar->file.bytes_remaining == 0) { + ret = advance_multivolume(a); + if(ret != ARCHIVE_OK) + return ret; + } + + if(rar->cstate.block_parsing_finished) { + ssize_t block_size; + + /* The header size won't be bigger than 6 bytes. */ + if(!read_ahead(a, 6, &p)) { + /* Failed to prefetch data block header. */ + return ARCHIVE_EOF; + } + + /* + * Read block_size by parsing block header. Validate the header + * by calculating CRC byte stored inside the header. Size of + * the header is not constant (block size can be stored either + * in 1 or 2 bytes), that's why block size is left out from the + * `compressed_block_header` structure and returned by + * `parse_block_header` as the second argument. */ + + ret = parse_block_header(a, p, &block_size, + &rar->last_block_hdr); + if(ret != ARCHIVE_OK) { + return ret; + } + + /* Skip block header. Next data is huffman tables, + * if present. */ + ssize_t to_skip = sizeof(struct compressed_block_header) + + bf_byte_count(&rar->last_block_hdr) + 1; + + if(ARCHIVE_OK != consume(a, to_skip)) + return ARCHIVE_EOF; + + rar->file.bytes_remaining -= to_skip; + + /* The block size gives information about the whole block size, + * but the block could be stored in split form when using + * multi-volume archives. In this case, the block size will be + * bigger than the actual data stored in this file. Remaining + * part of the data will be in another file. */ + + ssize_t cur_block_size = + rar5_min(rar->file.bytes_remaining, block_size); + + if(block_size > rar->file.bytes_remaining) { + /* If current blocks' size is bigger than our data + * size, this means we have a multivolume archive. + * In this case, skip all base headers until the end + * of the file, proceed to next "partXXX.rar" volume, + * find its signature, skip all headers up to the first + * FILE base header, and continue from there. + * + * Note that `merge_block` will update the `rar` + * context structure quite extensively. */ + + ret = merge_block(a, block_size, &p); + if(ret != ARCHIVE_OK) { + return ret; + } + + cur_block_size = block_size; + + /* Current stream pointer should be now directly + * *after* the block that spanned through multiple + * archive files. `p` pointer should have the data of + * the *whole* block (merged from partial blocks + * stored in multiple archives files). */ + } else { + rar->cstate.switch_multivolume = 0; + + /* Read the whole block size into memory. This can take + * up to 8 megabytes of memory in theoretical cases. + * Might be worth to optimize this and use a standard + * chunk of 4kb's. */ + if(!read_ahead(a, 4 + cur_block_size, &p)) { + /* Failed to prefetch block data. */ + return ARCHIVE_EOF; + } + } + + rar->cstate.block_buf = p; + rar->cstate.cur_block_size = cur_block_size; + rar->cstate.block_parsing_finished = 0; + + rar->bits.in_addr = 0; + rar->bits.bit_addr = 0; + + if(bf_is_table_present(&rar->last_block_hdr)) { + /* Load Huffman tables. */ + ret = parse_tables(a, rar, p); + if(ret != ARCHIVE_OK) { + /* Error during decompression of Huffman + * tables. */ + return ret; + } + } + } else { + /* Block parsing not finished, reuse previous memory buffer. */ + p = rar->cstate.block_buf; + } + + /* Uncompress the block, or a part of it, depending on how many bytes + * will be generated by uncompressing the block. + * + * In case too many bytes will be generated, calling this function + * again will resume the uncompression operation. */ + ret = do_uncompress_block(a, p); + if(ret != ARCHIVE_OK) { + return ret; + } + + if(rar->cstate.block_parsing_finished && + rar->cstate.switch_multivolume == 0 && + rar->cstate.cur_block_size > 0) + { + /* If we're processing a normal block, consume the whole + * block. We can do this because we've already read the whole + * block to memory. */ + if(ARCHIVE_OK != consume(a, rar->cstate.cur_block_size)) + return ARCHIVE_FATAL; + + rar->file.bytes_remaining -= rar->cstate.cur_block_size; + } else if(rar->cstate.switch_multivolume) { + /* Don't consume the block if we're doing multivolume + * processing. The volume switching function will consume + * the proper count of bytes instead. */ + rar->cstate.switch_multivolume = 0; + } + + return ARCHIVE_OK; +} + +/* Pops the `buf`, `size` and `offset` from the "data ready" stack. + * + * Returns ARCHIVE_OK when those arguments can be used, ARCHIVE_RETRY + * when there is no data on the stack. */ +static int use_data(struct rar5* rar, const void** buf, size_t* size, + int64_t* offset) +{ + int i; + + for(i = 0; i < rar5_countof(rar->cstate.dready); i++) { + struct data_ready *d = &rar->cstate.dready[i]; + + if(d->used) { + if(buf) *buf = d->buf; + if(size) *size = d->size; + if(offset) *offset = d->offset; + + d->used = 0; + return ARCHIVE_OK; + } + } + + return ARCHIVE_RETRY; +} + +/* Pushes the `buf`, `size` and `offset` arguments to the rar->cstate.dready + * FIFO stack. Those values will be popped from this stack by the `use_data` + * function. */ +static int push_data_ready(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, size_t size, int64_t offset) +{ + int i; + + /* Don't push if we're in skip mode. This is needed because solid + * streams need full processing even if we're skipping data. After + * fully processing the stream, we need to discard the generated bytes, + * because we're interested only in the side effect: building up the + * internal window circular buffer. This window buffer will be used + * later during unpacking of requested data. */ + if(rar->skip_mode) + return ARCHIVE_OK; + + /* Sanity check. */ + if(offset != rar->file.last_offset + rar->file.last_size) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Sanity check error: output stream is not continuous"); + return ARCHIVE_FATAL; + } + + for(i = 0; i < rar5_countof(rar->cstate.dready); i++) { + struct data_ready* d = &rar->cstate.dready[i]; + if(!d->used) { + d->used = 1; + d->buf = buf; + d->size = size; + d->offset = offset; + + /* These fields are used only in sanity checking. */ + rar->file.last_offset = offset; + rar->file.last_size = size; + + /* Calculate the checksum of this new block before + * submitting data to libarchive's engine. */ + update_crc(rar, d->buf, d->size); + + return ARCHIVE_OK; + } + } + + /* Program counter will reach this code if the `rar->cstate.data_ready` + * stack will be filled up so that no new entries will be allowed. The + * code shouldn't allow such situation to occur. So we treat this case + * as an internal error. */ + + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Error: premature end of data_ready stack"); + return ARCHIVE_FATAL; +} + +/* This function uncompresses the data that is stored in the <FILE> base + * block. + * + * The FILE base block looks like this: + * + * <header><huffman tables><block_1><block_2>...<block_n> + * + * The <header> is a block header, that is parsed in parse_block_header(). + * It's a "compressed_block_header" structure, containing metadata needed + * to know when we should stop looking for more <block_n> blocks. + * + * <huffman tables> contain data needed to set up the huffman tables, needed + * for the actual decompression. + * + * Each <block_n> consists of series of literals: + * + * <literal><literal><literal>...<literal> + * + * Those literals generate the uncompression data. They operate on a circular + * buffer, sometimes writing raw data into it, sometimes referencing + * some previous data inside this buffer, and sometimes declaring a filter + * that will need to be executed on the data stored in the circular buffer. + * It all depends on the literal that is used. + * + * Sometimes blocks produce output data, sometimes they don't. For example, for + * some huge files that use lots of filters, sometimes a block is filled with + * only filter declaration literals. Such blocks won't produce any data in the + * circular buffer. + * + * Sometimes blocks will produce 4 bytes of data, and sometimes 1 megabyte, + * because a literal can reference previously decompressed data. For example, + * there can be a literal that says: 'append a byte 0xFE here', and after + * it another literal can say 'append 1 megabyte of data from circular buffer + * offset 0x12345'. This is how RAR format handles compressing repeated + * patterns. + * + * The RAR compressor creates those literals and the actual efficiency of + * compression depends on what those literals are. The literals can also + * be seen as a kind of a non-turing-complete virtual machine that simply + * tells the decompressor what it should do. + * */ + +static int do_uncompress_file(struct archive_read* a) { + struct rar5* rar = get_context(a); + int ret; + int64_t max_end_pos; + + if(!rar->cstate.initialized) { + /* Don't perform full context reinitialization if we're + * processing a solid archive. */ + if(!rar->main.solid || !rar->cstate.window_buf) { + init_unpack(rar); + } + + rar->cstate.initialized = 1; + } + + if(rar->cstate.all_filters_applied == 1) { + /* We use while(1) here, but standard case allows for just 1 + * iteration. The loop will iterate if process_block() didn't + * generate any data at all. This can happen if the block + * contains only filter definitions (this is common in big + * files). */ + while(1) { + ret = process_block(a); + if(ret == ARCHIVE_EOF || ret == ARCHIVE_FATAL) + return ret; + + if(rar->cstate.last_write_ptr == + rar->cstate.write_ptr) { + /* The block didn't generate any new data, + * so just process a new block. */ + continue; + } + + /* The block has generated some new data, so break + * the loop. */ + break; + } + } + + /* Try to run filters. If filters won't be applied, it means that + * insufficient data was generated. */ + ret = apply_filters(a); + if(ret == ARCHIVE_RETRY) { + return ARCHIVE_OK; + } else if(ret == ARCHIVE_FATAL) { + return ARCHIVE_FATAL; + } + + /* If apply_filters() will return ARCHIVE_OK, we can continue here. */ + + if(cdeque_size(&rar->cstate.filters) > 0) { + /* Check if we can write something before hitting first + * filter. */ + struct filter_info* flt; + + /* Get the block_start offset from the first filter. */ + if(CDE_OK != cdeque_front(&rar->cstate.filters, + cdeque_filter_p(&flt))) + { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Can't read first filter"); + return ARCHIVE_FATAL; + } + + max_end_pos = rar5_min(flt->block_start, + rar->cstate.write_ptr); + } else { + /* There are no filters defined, or all filters were applied. + * This means we can just store the data without any + * postprocessing. */ + max_end_pos = rar->cstate.write_ptr; + } + + if(max_end_pos == rar->cstate.last_write_ptr) { + /* We can't write anything yet. The block uncompression + * function did not generate enough data, and no filter can be + * applied. At the same time we don't have any data that can be + * stored without filter postprocessing. This means we need to + * wait for more data to be generated, so we can apply the + * filters. + * + * Signal the caller that we need more data to be able to do + * anything. + */ + return ARCHIVE_RETRY; + } else { + /* We can write the data before hitting the first filter. + * So let's do it. The push_window_data() function will + * effectively return the selected data block to the user + * application. */ + push_window_data(a, rar, rar->cstate.last_write_ptr, + max_end_pos); + rar->cstate.last_write_ptr = max_end_pos; + } + + return ARCHIVE_OK; +} + +static int uncompress_file(struct archive_read* a) { + int ret; + + while(1) { + /* Sometimes the uncompression function will return a + * 'retry' signal. If this will happen, we have to retry + * the function. */ + ret = do_uncompress_file(a); + if(ret != ARCHIVE_RETRY) + return ret; + } +} + + +static int do_unstore_file(struct archive_read* a, + struct rar5* rar, const void** buf, size_t* size, int64_t* offset) +{ + const uint8_t* p; + + if(rar->file.bytes_remaining == 0 && rar->main.volume > 0 && + rar->generic.split_after > 0) + { + int ret; + + rar->cstate.switch_multivolume = 1; + ret = advance_multivolume(a); + rar->cstate.switch_multivolume = 0; + + if(ret != ARCHIVE_OK) { + /* Failed to advance to next multivolume archive + * file. */ + return ret; + } + } + + size_t to_read = rar5_min(rar->file.bytes_remaining, 64 * 1024); + if(to_read == 0) { + return ARCHIVE_EOF; + } + + if(!read_ahead(a, to_read, &p)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "I/O error when unstoring file"); + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != consume(a, to_read)) { + return ARCHIVE_EOF; + } + + if(buf) *buf = p; + if(size) *size = to_read; + if(offset) *offset = rar->cstate.last_unstore_ptr; + + rar->file.bytes_remaining -= to_read; + rar->cstate.last_unstore_ptr += to_read; + + update_crc(rar, p, to_read); + return ARCHIVE_OK; +} + +static int do_unpack(struct archive_read* a, struct rar5* rar, + const void** buf, size_t* size, int64_t* offset) +{ + enum COMPRESSION_METHOD { + STORE = 0, FASTEST = 1, FAST = 2, NORMAL = 3, GOOD = 4, + BEST = 5 + }; + + if(rar->file.service > 0) { + return do_unstore_file(a, rar, buf, size, offset); + } else { + switch(rar->cstate.method) { + case STORE: + return do_unstore_file(a, rar, buf, size, + offset); + case FASTEST: + /* fallthrough */ + case FAST: + /* fallthrough */ + case NORMAL: + /* fallthrough */ + case GOOD: + /* fallthrough */ + case BEST: + return uncompress_file(a); + default: + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Compression method not supported: 0x%x", + rar->cstate.method); + + return ARCHIVE_FATAL; + } + } + +#if !defined WIN32 + /* Not reached. */ + return ARCHIVE_OK; +#endif +} + +static int verify_checksums(struct archive_read* a) { + int verify_crc; + struct rar5* rar = get_context(a); + + /* Check checksums only when actually unpacking the data. There's no + * need to calculate checksum when we're skipping data in solid archives + * (skipping in solid archives is the same thing as unpacking compressed + * data and discarding the result). */ + + if(!rar->skip_mode) { + /* Always check checksums if we're not in skip mode */ + verify_crc = 1; + } else { + /* We can override the logic above with a compile-time option + * NO_CRC_ON_SOLID_SKIP. This option is used during debugging, + * and it will check checksums of unpacked data even when + * we're skipping it. */ + +#if defined CHECK_CRC_ON_SOLID_SKIP + /* Debug case */ + verify_crc = 1; +#else + /* Normal case */ + verify_crc = 0; +#endif + } + + if(verify_crc) { + /* During unpacking, on each unpacked block we're calling the + * update_crc() function. Since we are here, the unpacking + * process is already over and we can check if calculated + * checksum (CRC32 or BLAKE2sp) is the same as what is stored + * in the archive. */ + if(rar->file.stored_crc32 > 0) { + /* Check CRC32 only when the file contains a CRC32 + * value for this file. */ + + if(rar->file.calculated_crc32 != + rar->file.stored_crc32) { + /* Checksums do not match; the unpacked file + * is corrupted. */ + + DEBUG_CODE { + printf("Checksum error: CRC32 " + "(was: %08x, expected: %08x)\n", + rar->file.calculated_crc32, + rar->file.stored_crc32); + } + +#ifndef DONT_FAIL_ON_CRC_ERROR + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Checksum error: CRC32"); + return ARCHIVE_FATAL; +#endif + } else { + DEBUG_CODE { + printf("Checksum OK: CRC32 " + "(%08x/%08x)\n", + rar->file.stored_crc32, + rar->file.calculated_crc32); + } + } + } + + if(rar->file.has_blake2 > 0) { + /* BLAKE2sp is an optional checksum algorithm that is + * added to RARv5 archives when using the `-htb` switch + * during creation of archive. + * + * We now finalize the hash calculation by calling the + * `final` function. This will generate the final hash + * value we can use to compare it with the BLAKE2sp + * checksum that is stored in the archive. + * + * The return value of this `final` function is not + * very helpful, as it guards only against improper use. + * This is why we're explicitly ignoring it. */ + + uint8_t b2_buf[32]; + (void) blake2sp_final(&rar->file.b2state, b2_buf, 32); + + if(memcmp(&rar->file.blake2sp, b2_buf, 32) != 0) { +#ifndef DONT_FAIL_ON_CRC_ERROR + archive_set_error(&a->archive, + ARCHIVE_ERRNO_FILE_FORMAT, + "Checksum error: BLAKE2"); + + return ARCHIVE_FATAL; +#endif + } + } + } + + /* Finalization for this file has been successfully completed. */ + return ARCHIVE_OK; +} + +static int verify_global_checksums(struct archive_read* a) { + return verify_checksums(a); +} + +static int rar5_read_data(struct archive_read *a, const void **buff, + size_t *size, int64_t *offset) { + int ret; + struct rar5* rar = get_context(a); + + if(rar->file.dir > 0) { + /* Don't process any data if this file entry was declared + * as a directory. This is needed, because entries marked as + * directory doesn't have any dictionary buffer allocated, so + * it's impossible to perform any decompression. */ + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Can't decompress an entry marked as a directory"); + return ARCHIVE_FAILED; + } + + if(!rar->skip_mode && (rar->cstate.last_write_ptr > rar->file.unpacked_size)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Unpacker has written too many bytes"); + return ARCHIVE_FATAL; + } + + ret = use_data(rar, buff, size, offset); + if(ret == ARCHIVE_OK) { + return ret; + } + + if(rar->file.eof == 1) { + return ARCHIVE_EOF; + } + + ret = do_unpack(a, rar, buff, size, offset); + if(ret != ARCHIVE_OK) { + return ret; + } + + if(rar->file.bytes_remaining == 0 && + rar->cstate.last_write_ptr == rar->file.unpacked_size) + { + /* If all bytes of current file were processed, run + * finalization. + * + * Finalization will check checksum against proper values. If + * some of the checksums will not match, we'll return an error + * value in the last `archive_read_data` call to signal an error + * to the user. */ + + rar->file.eof = 1; + return verify_global_checksums(a); + } + + return ARCHIVE_OK; +} + +static int rar5_read_data_skip(struct archive_read *a) { + struct rar5* rar = get_context(a); + + if(rar->main.solid) { + /* In solid archives, instead of skipping the data, we need to + * extract it, and dispose the result. The side effect of this + * operation will be setting up the initial window buffer state + * needed to be able to extract the selected file. */ + + int ret; + + /* Make sure to process all blocks in the compressed stream. */ + while(rar->file.bytes_remaining > 0) { + /* Setting the "skip mode" will allow us to skip + * checksum checks during data skipping. Checking the + * checksum of skipped data isn't really necessary and + * it's only slowing things down. + * + * This is incremented instead of setting to 1 because + * this data skipping function can be called + * recursively. */ + rar->skip_mode++; + + /* We're disposing 1 block of data, so we use triple + * NULLs in arguments. */ + ret = rar5_read_data(a, NULL, NULL, NULL); + + /* Turn off "skip mode". */ + rar->skip_mode--; + + if(ret < 0) { + /* Propagate any potential error conditions + * to the caller. */ + return ret; + } + } + } else { + /* In standard archives, we can just jump over the compressed + * stream. Each file in non-solid archives starts from an empty + * window buffer. */ + + if(ARCHIVE_OK != consume(a, rar->file.bytes_remaining)) { + return ARCHIVE_FATAL; + } + + rar->file.bytes_remaining = 0; + } + + return ARCHIVE_OK; +} + +static int64_t rar5_seek_data(struct archive_read *a, int64_t offset, + int whence) +{ + (void) a; + (void) offset; + (void) whence; + + /* We're a streaming unpacker, and we don't support seeking. */ + + return ARCHIVE_FATAL; +} + +static int rar5_cleanup(struct archive_read *a) { + struct rar5* rar = get_context(a); + + free(rar->cstate.window_buf); + free(rar->cstate.filtered_buf); + + free(rar->vol.push_buf); + + free_filters(rar); + cdeque_free(&rar->cstate.filters); + + free(rar); + a->format->data = NULL; + + return ARCHIVE_OK; +} + +static int rar5_capabilities(struct archive_read * a) { + (void) a; + return 0; +} + +static int rar5_has_encrypted_entries(struct archive_read *_a) { + (void) _a; + + /* Unsupported for now. */ + return ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED; +} + +static int rar5_init(struct rar5* rar) { + ssize_t i; + + memset(rar, 0, sizeof(struct rar5)); + + /* Decrypt the magic signature pattern. Check the comment near the + * `rar5_signature` symbol to read the rationale behind this. */ + + if(rar5_signature[0] == 243) { + for(i = 0; i < rar5_signature_size; i++) { + rar5_signature[i] ^= 0xA1; + } + } + + if(CDE_OK != cdeque_init(&rar->cstate.filters, 8192)) + return ARCHIVE_FATAL; + + return ARCHIVE_OK; +} + +int archive_read_support_format_rar5(struct archive *_a) { + struct archive_read* ar; + int ret; + struct rar5* rar; + + if(ARCHIVE_OK != (ret = get_archive_read(_a, &ar))) + return ret; + + rar = malloc(sizeof(*rar)); + if(rar == NULL) { + archive_set_error(&ar->archive, ENOMEM, + "Can't allocate rar5 data"); + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != rar5_init(rar)) { + archive_set_error(&ar->archive, ENOMEM, + "Can't allocate rar5 filter buffer"); + return ARCHIVE_FATAL; + } + + ret = __archive_read_register_format(ar, + rar, + "rar5", + rar5_bid, + rar5_options, + rar5_read_header, + rar5_read_data, + rar5_read_data_skip, + rar5_seek_data, + rar5_cleanup, + rar5_capabilities, + rar5_has_encrypted_entries); + + if(ret != ARCHIVE_OK) { + (void) rar5_cleanup(ar); + } + + return ret; +} |