diff options
Diffstat (limited to 'debian/sensible_mda/sensible-mda.c')
| -rw-r--r-- | debian/sensible_mda/sensible-mda.c | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/debian/sensible_mda/sensible-mda.c b/debian/sensible_mda/sensible-mda.c new file mode 100644 index 0000000..4278f99 --- /dev/null +++ b/debian/sensible_mda/sensible-mda.c @@ -0,0 +1,350 @@ +/* + * $Sendmail: sensible-mda.c,v 8.14.3 2009-02-28 22:32:11 cowboy Exp $ + * + * sensible-mda.c + * Copyright (c) 1998, Johnie Ingram. + * Copyright (c) 1998-2009 Richard Nelson <cowboy@debian.org>. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#ifndef lint +static const char id[] = "@(#)$Id: sensible-mda.c,v 8.14.3 2009-02-28 22:32:11 cowboy Exp $"; +#endif /* ! lint */ + +#include <stdio.h> +#include <stdlib.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <limits.h> +#include <unistd.h> +#include <pwd.h> +#include <grp.h> +#include <sysexits.h> +#include <string.h> +#include <syslog.h> + +// TODO: declare -x TCPREMOTEIP="$3" + +# define min(a, b) ((a) < (b) ? (a) : (b)) + +#ifndef DEBUG + #define DEBUG 0 + #endif +#ifndef TESTING + #define TESTING 0 + #endif + +#define PROCMAIL "/etc/mail/smrsh/procmail" +#define MAILDROP "/etc/mail/smrsh/maildrop" +#define DELIVER "/etc/mail/smrsh/deliver" +#define MAIL_LOCAL "/etc/mail/smrsh/mail.local" + +#define PROCMAILRCS "/etc/procmailrcs/" + +static void help(void); +static int drop_privs(char *, uid_t, gid_t); +static void show_privs(void); +static unsigned char program[PATH_MAX]; + +static uid_t RealUid, RunAsUid; +static gid_t RealGid, RunAsGid; + +int +main (int argc, char *argv[]) { + + struct stat MDA_stat; + int done = 1; + struct passwd* passwd_entry; + + char *str_pos; + int exec_rc = EX_OK; + + #if DEBUG + int arg_index; + int str_len; + #endif + + (void) openlog( "sensible-mda", LOG_PID+LOG_PERROR, LOG_MAIL ); + + /*---------------------------------------------------------------- + * Obtain program name + *----------------------------------------------------------------*/ + str_pos = strrchr(argv[0], '/'); + if ( str_pos ) + str_pos++; + else + str_pos = argv[0]; + (void) strncpy(program, str_pos, + min(strlen(str_pos), sizeof(program)-1)); + program[sizeof(program)-1] = '\0'; + + #if DEBUG + str_len = 0; + for ( arg_index = 0; arg_index < argc; arg_index++ ) + str_len += strlen( argv[arg_index] ) + 1; + str_pos = malloc( str_len + 1); + str_pos[0] = '\0'; + for ( arg_index = 0; arg_index < argc; arg_index++ ) { + (void) strcat( str_pos, argv[arg_index] ); + (void) strcat( str_pos, " " ); + }; + (void) syslog( LOG_INFO, "Parms: %s\n", str_pos ); + (void) free(str_pos); + #endif + + /*---------------------------------------------------------------- + * Parse input to determine to whom to speak and who we are... + * Must have at least three parameters unless first is ?,-?,/?. + *----------------------------------------------------------------*/ + if (argc >= 2 && + (strcmp(argv[1],"?") == 0 || strcmp(argv[1],"-?") == 0 || + strcmp(argv[1],"/?") == 0 || strcmp(argv[1],"\\?") == 0 || + strcmp(argv[1],"-h") == 0 || strcmp(argv[1],"--help") == 0)) { + (void) printf( "%s - Help\n", program ); + help(); + (void) closelog(); + return (EX_USAGE); + }; + if (argc < 3) { + (void) syslog( LOG_ERR, "%s - Required parameters elided.\n", + program ); + help(); + (void) closelog(); + return (EX_USAGE); + }; + + /*---------------------------------------------------------------- + * Determine to whom we are delivering mail to, and set that + * as our real, effective, and saved {u,g}ids + *----------------------------------------------------------------*/ + RealUid = RunAsUid = geteuid(); + RealGid = RunAsGid = getegid(); + passwd_entry=getpwnam(argv[2]); + if (passwd_entry) { + RunAsUid = passwd_entry->pw_uid; + RunAsGid = passwd_entry->pw_gid; + } + else { + (void) syslog( LOG_ERR, "User(%s) does not exist!\n", + argv[2]); + (void) closelog(); + return (EX_TEMPFAIL); + }; + + /*---------------------------------------------------------------- + * 1st: try delivery via PROCMAIL (Keep SUID, works better that way) + *----------------------------------------------------------------*/ + if (!stat(PROCMAIL, &MDA_stat)) { + done = 0; + #if DEBUG + (void) syslog( LOG_INFO, "MDA: %s -t -f %s" + " -a %s -d %s\n", + PROCMAIL, argv[1], argv[3], argv[2]); + #endif + #if ! TESTING + exec_rc = execl (PROCMAIL, PROCMAIL, "-t", + "-f", argv[1], + "-a", argv[3], + "-d", argv[2], NULL); + (void) syslog( LOG_ERR, "%s did not execute %i,%i\n", + PROCMAIL, exec_rc, errno); + (void) closelog(); + return (EX_TEMPFAIL); + #endif + done = 1; + }; + + /*---------------------------------------------------------------- + * 2nd: try delivery via MAILDROP + *----------------------------------------------------------------*/ + if (done && !stat(MAILDROP, &MDA_stat)) { + done = 0; + #if DEBUG + (void) syslog( LOG_INFO, "MDA: %s -f %s -d %s %s\n", + MAILDROP, argv[1], argv[2], argv[3]); + #endif + if (drop_privs( argv[2], RunAsUid, RunAsGid )) { + (void) closelog(); + return (EX_TEMPFAIL); + }; + #if ! TESTING + exec_rc = execl (MAILDROP, MAILDROP, + "-f", argv[1], "-d", argv[2], argv[3], NULL); + (void) syslog( LOG_ERR, "%s did not execute %i,%i\n", + MAILDROP, exec_rc, errno); + (void) closelog(); + return (EX_TEMPFAIL); + #endif + done = 1; + }; + + /*---------------------------------------------------------------- + * 3rd: try delivery via DELIVER + *----------------------------------------------------------------*/ + if (done && !stat(DELIVER, &MDA_stat)) { + done = 0; + #if DEBUG + (void) syslog( LOG_INFO, "MDA: %s -r %s %s\n", + DELIVER, argv[1], argv[2]); + #endif + if (drop_privs( argv[2], RunAsUid, RunAsGid )) { + (void) closelog(); + return (EX_TEMPFAIL); + }; + #if ! TESTING + exec_rc = execl (DELIVER, DELIVER, + "-r", argv[1], argv[2], NULL); + (void) syslog( LOG_ERR, "%s did not execute %i,%i\n", + DELIVER, exec_rc, errno); + (void) closelog(); + return (EX_TEMPFAIL); + #endif + done = 1; + }; + + /*---------------------------------------------------------------- + * 4th: try delivery via MAIL.LOCAL (Needs SUID because of LMTP) + *----------------------------------------------------------------*/ + if (done && !stat(MAIL_LOCAL, &MDA_stat)) { + done = 0; + #if DEBUG + (void) syslog( LOG_INFO, "MDA: %s -f %s %s\n", + MAIL_LOCAL, argv[1], argv[2]); + #endif + #if ! TESTING + exec_rc = execl (MAIL_LOCAL, MAIL_LOCAL, + "-f", argv[1], argv[2], NULL); + (void) syslog( LOG_ERR, "%s did not execute %i,%i\n", + MAIL_LOCAL, exec_rc, errno); + (void) closelog(); + return (EX_TEMPFAIL); + #endif + done = 1; + }; + + (void) syslog( LOG_ERR, "No MDA was found! Tried: " + "%s, %s, %s, and %s.\n", + PROCMAIL, MAILDROP, DELIVER, MAIL_LOCAL ); + + (void) closelog(); + return (EX_TEMPFAIL); + }; + +/*------------------------------------------------------------------- + * drop_privs... + *-------------------------------------------------------------------*/ +static int +drop_privs(char * luser, uid_t new_uid, gid_t new_gid) { + gid_t emptygidset[1]; + uid_t EffUid; + gid_t EffGid; + int rval; + + rval = EX_OK; + EffUid = geteuid(); + EffGid = getegid(); + + /* reset group permissions; these can be set later */ + emptygidset[0] = (RunAsGid != 0) ? RunAsGid : EffGid; + if (setgroups(1, emptygidset) == -1 && EffUid == 0) { + (void) syslog( LOG_ERR, "drop_privs: setgroups(1, %d) failed\n", + (int) emptygidset[0]); + rval = EX_OSERR; + }; + + /* reset primary group id */ + if ((RunAsGid != 0) && EffGid != RunAsGid && setgid(RunAsGid) < 0) { + (void) syslog( LOG_ERR, "drop_privs: setgid(%d) failed\n", + (int) RunAsGid); + rval = EX_OSERR; + }; + + /* reset primary user id */ + if ((RunAsUid != 0) && EffUid != RunAsUid && setuid(RunAsUid) < 0) { + (void) syslog( LOG_ERR, "drop_privs: setuid(%d) failed\n", + (int) RunAsUid); + rval = EX_OSERR; + }; + + #if DEBUG + show_privs(); + (void) syslog( LOG_INFO, "drop_privs: rval = %d\n", rval); + #endif + + if (rval) { + (void) syslog( LOG_ERR, + "Can not setreuid to %d:%d for user(%s)!\n", + RunAsUid, RunAsGid, luser); + show_privs(); + }; + + return rval; + }; + +/*------------------------------------------------------------------- + * show_privs... + *-------------------------------------------------------------------*/ +static void +show_privs(void) { + + (void) syslog( LOG_INFO, "show_privs: RealUser = %d:%d\n", + (int) RealUid, (int) RealGid); + (void) syslog( LOG_INFO, "show_privs: " + "get[ug]id=%d:%d, gete[ug]id=%d:%d\n", + (int) getuid(), (int) getgid(), + (int) geteuid(), (int) getegid()); + (void) syslog( LOG_INFO, "show_privs: RunAsUser = %d:%d\n", + (int) RunAsUid, (int) RunAsGid); + return; + }; + +/*------------------------------------------------------------------- + * Help... + *-------------------------------------------------------------------*/ +static void +help(void) { + + (void) printf("\n%s - Help information.\n\n" + "%s:\n" + "\tA general MTA->MDA wrapper to isolate the MTA from\n" + "\tthe vagaries of MDA installation and invocation.\n" + "\nSupported MTAs:\n" + "\tsendmail\n" + "\nSupported MDAs:\n" + "\tprocmail, maildrop, deliver, mail.local\n" + "\nCalled by:\n" + "\tSendmail: \n" + "\tYou: " + "Go directly to jail, do not pass GO, " + "do not collect $200!\n" + "\nSyntax:\n" + "\t%s <from:$g> <user:$u> [<detail:$h>]" + "[<client:${client_addr}>]\n" + "\nCalls:\n" + "\tprocmail:\t procmail -t" + " -f <from>" + " -a <detail> -d <to>\n" + "\tmaildrop:\t maildrop -f <from> -d <to> <detail>\n" + "\tdeliver:\t deliver -r <from> <to>\n" + "\tmail.local:\t mail.local -f <from> <to>\n" + "\n" + ,program, program, program + ); + return; + }; + |