6616927 preserve MAC contexts between packets

1 files changed, 75 insertions, 33 deletions

diff --git a/usr/src/cmd/ssh/libssh/common/mac.c b/usr/src/cmd/ssh/libssh/common/mac.c
index c04a2746f1..e25f5eb95d 100644
--- a/usr/src/cmd/ssh/libssh/common/mac.c
+++ b/usr/src/cmd/ssh/libssh/common/mac.c
@@ -1,8 +1,4 @@
 /*
- * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
- */
-/*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -29,8 +25,6 @@
 #include "includes.h"
 RCSID("$OpenBSD: mac.c,v 1.5 2002/05/16 22:02:50 markus Exp $");
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <openssl/hmac.h>
 
 #include "xmalloc.h"
@@ -39,63 +33,111 @@ RCSID("$OpenBSD: mac.c,v 1.5 2002/05/16 22:02:50 markus Exp $");
 #include "cipher.h"
 #include "kex.h"
 #include "mac.h"
+#include "misc.h"
+
+#define SSH_EVP		1	/* OpenSSL EVP-based MAC */
 
 struct {
 	char		*name;
+	int		type;
 	const EVP_MD *	(*mdfunc)(void);
 	int		truncatebits;	/* truncate digest if != 0 */
+	int		key_len;	/* will be used if we have UMAC */
 } macs[] = {
-	{ "hmac-sha1",			EVP_sha1, 0 },
-	{ "hmac-sha1-96",		EVP_sha1, 96 },
-	{ "hmac-md5",			EVP_md5, 0 },
-	{ "hmac-md5-96",		EVP_md5, 96 },
+	{ "hmac-sha1",			SSH_EVP, EVP_sha1,	 0, -1 },
+	{ "hmac-sha1-96",		SSH_EVP, EVP_sha1,	96, -1 },
+	{ "hmac-md5",			SSH_EVP, EVP_md5,	 0, -1 },
+	{ "hmac-md5-96",		SSH_EVP, EVP_md5,	96, -1 },
 #ifdef SOLARIS_SSH_ENABLE_RIPEMD160
-	{ "hmac-ripemd160",		EVP_ripemd160, 0 },
-	{ "hmac-ripemd160@openssh.com",	EVP_ripemd160, 0 },
+	{ "hmac-ripemd160",		SSH_EVP, EVP_ripemd160,  0, -1 },
+	{ "hmac-ripemd160@openssh.com",	SSH_EVP, EVP_ripemd160,  0, -1 },
 #endif /* SOLARIS_SSH_ENABLE_RIPEMD160 */
-	{ NULL,				NULL, 0 }
+	{ NULL,				0,	 NULL,		 0, -1 }
 };
 
+static void
+mac_setup_by_id(Mac *mac, int which)
+{
+	int evp_len;
+	mac->type = macs[which].type;
+	if (mac->type == SSH_EVP) {
+		mac->evp_md = (*macs[which].mdfunc)();
+		if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
+			fatal("mac %s len %d", mac->name, evp_len);
+		mac->key_len = mac->mac_len = (u_int)evp_len;
+	} else
+		fatal("wrong MAC type (%d)", mac->type);
+	if (macs[which].truncatebits != 0)
+		mac->mac_len = macs[which].truncatebits / 8;
+}
+
 int
-mac_init(Mac *mac, char *name)
+mac_setup(Mac *mac, char *name)
 {
 	int i;
+
 	for (i = 0; macs[i].name; i++) {
 		if (strcmp(name, macs[i].name) == 0) {
-			if (mac != NULL) {
-				mac->md = (*macs[i].mdfunc)();
-				mac->key_len = mac->mac_len = EVP_MD_size(mac->md);
-				if (macs[i].truncatebits != 0)
-					mac->mac_len = macs[i].truncatebits/8;
-			}
-			debug2("mac_init: found %s", name);
+			if (mac != NULL)
+				mac_setup_by_id(mac, i);
+			debug2("mac_setup: found %s", name);
 			return (0);
 		}
 	}
-	debug2("mac_init: unknown %s", name);
+	debug2("mac_setup: unknown %s", name);
 	return (-1);
 }
 
+int
+mac_init(Mac *mac)
+{
+	if (mac->key == NULL)
+		fatal("mac_init: no key");
+	switch (mac->type) {
+	case SSH_EVP:
+		if (mac->evp_md == NULL)
+			return -1;
+		HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
+		return 0;
+	default:
+		return -1;
+	}
+}
+
 u_char *
 mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
 {
-	HMAC_CTX c;
 	static u_char m[EVP_MAX_MD_SIZE];
 	u_char b[4];
 
-	if (mac->key == NULL)
-		fatal("mac_compute: no key");
 	if (mac->mac_len > sizeof(m))
-		fatal("mac_compute: mac too long");
-	HMAC_Init(&c, mac->key, mac->key_len, mac->md);
-	PUT_32BIT(b, seqno);
-	HMAC_Update(&c, b, sizeof(b));
-	HMAC_Update(&c, data, datalen);
-	HMAC_Final(&c, m, NULL);
-	HMAC_cleanup(&c);
+		fatal("mac_compute: mac too long %u %lu",
+		    mac->mac_len, (u_long)sizeof(m));
+
+	switch (mac->type) {
+	case SSH_EVP:
+		put_u32(b, seqno);
+		/* reset HMAC context */
+		HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
+		HMAC_Update(&mac->evp_ctx, b, sizeof(b));
+		HMAC_Update(&mac->evp_ctx, data, datalen);
+		HMAC_Final(&mac->evp_ctx, m, NULL);
+		break;
+	default:
+		fatal("mac_compute: unknown MAC type");
+	}
+
 	return (m);
 }
 
+void
+mac_clear(Mac *mac)
+{
+	if (mac->evp_md != NULL)
+		HMAC_cleanup(&mac->evp_ctx);
+	mac->evp_md = NULL;
+}
+
 /* XXX copied from ciphers_valid */
 #define	MAC_SEP	","
 int
@@ -108,7 +150,7 @@ mac_valid(const char *names)
 	maclist = cp = xstrdup(names);
 	for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
 	    (p = strsep(&cp, MAC_SEP))) {
-		if (mac_init(NULL, p) < 0) {
+		if (mac_setup(NULL, p) < 0) {
 			debug("bad mac %s [%s]", p, names);
 			xfree(maclist);
 			return (0);