-/* $OpenBSD: mac.c,v 1.16 2011/08/02 01:22:11 djm Exp $ */
+/* $OpenBSD: mac.c,v 1.32 2015/01/15 18:32:54 naddy Exp $ */
/*
* Copyright (c) 2001 Markus Friedl. All rights reserved.
*
#include <sys/types.h>
-#include <openssl/hmac.h>
-
-#include <stdarg.h>
#include <string.h>
-#include <signal.h>
-
-#include "xmalloc.h"
-#include "log.h"
-#include "cipher.h"
-#include "buffer.h"
-#include "key.h"
-#include "kex.h"
+#include <stdio.h>
+
+#include "digest.h"
+#include "hmac.h"
+#include "umac.h"
#include "mac.h"
#include "misc.h"
+#include "ssherr.h"
+#include "sshbuf.h"
-#include "umac.h"
+#include "openbsd-compat/openssl-compat.h"
-#define SSH_EVP 1 /* OpenSSL EVP-based MAC */
+#define SSH_DIGEST 1 /* SSH_DIGEST_XXX */
#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
+#define SSH_UMAC128 3
-struct {
+struct macalg {
char *name;
int type;
- const EVP_MD * (*mdfunc)(void);
+ int alg;
int truncatebits; /* truncate digest if != 0 */
int key_len; /* just for UMAC */
int len; /* just for UMAC */
-} macs[] = {
- { "hmac-sha1", SSH_EVP, EVP_sha1, 0, -1, -1 },
- { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, -1, -1 },
+ int etm; /* Encrypt-then-MAC */
+};
+
+static const struct macalg macs[] = {
+ /* Encrypt-and-MAC (encrypt-and-authenticate) variants */
+ { "hmac-sha1", SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 0 },
+ { "hmac-sha1-96", SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 0 },
#ifdef HAVE_EVP_SHA256
- { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, -1, -1 },
- { "hmac-sha2-256-96", SSH_EVP, EVP_sha256, 96, -1, -1 },
- { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, -1, -1 },
- { "hmac-sha2-512-96", SSH_EVP, EVP_sha512, 96, -1, -1 },
+ { "hmac-sha2-256", SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 0 },
+ { "hmac-sha2-512", SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 0 },
+#endif
+ { "hmac-md5", SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 0 },
+ { "hmac-md5-96", SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 0 },
+#if defined(HAVE_EVP_RIPEMD)
+ { "hmac-ripemd160", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 },
+ { "hmac-ripemd160@openssh.com", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 },
#endif
- { "hmac-md5", SSH_EVP, EVP_md5, 0, -1, -1 },
- { "hmac-md5-96", SSH_EVP, EVP_md5, 96, -1, -1 },
-#ifdef HAVE_EVP_RIPEMD
- { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
- { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
+ { "umac-64@openssh.com", SSH_UMAC, 0, 0, 128, 64, 0 },
+ { "umac-128@openssh.com", SSH_UMAC128, 0, 0, 128, 128, 0 },
+
+ /* Encrypt-then-MAC variants */
+ { "hmac-sha1-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 1 },
+ { "hmac-sha1-96-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 1 },
+#ifdef HAVE_EVP_SHA256
+ { "hmac-sha2-256-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 1 },
+ { "hmac-sha2-512-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 1 },
#endif
- { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64 },
- { NULL, 0, NULL, 0, -1, -1 }
+ { "hmac-md5-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 1 },
+ { "hmac-md5-96-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 1 },
+ { "hmac-ripemd160-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 1 },
+ { "umac-64-etm@openssh.com", SSH_UMAC, 0, 0, 128, 64, 1 },
+ { "umac-128-etm@openssh.com", SSH_UMAC128, 0, 0, 128, 128, 1 },
+
+ { NULL, 0, 0, 0, 0, 0, 0 }
};
-static void
-mac_setup_by_id(Mac *mac, int which)
+/* Returns a list of supported MACs separated by the specified char. */
+char *
+mac_alg_list(char sep)
{
- 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;
+ char *ret = NULL, *tmp;
+ size_t nlen, rlen = 0;
+ const struct macalg *m;
+
+ for (m = macs; m->name != NULL; m++) {
+ if (ret != NULL)
+ ret[rlen++] = sep;
+ nlen = strlen(m->name);
+ if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
+ free(ret);
+ return NULL;
+ }
+ ret = tmp;
+ memcpy(ret + rlen, m->name, nlen + 1);
+ rlen += nlen;
+ }
+ return ret;
+}
+
+static int
+mac_setup_by_alg(struct sshmac *mac, const struct macalg *macalg)
+{
+ mac->type = macalg->type;
+ if (mac->type == SSH_DIGEST) {
+ if ((mac->hmac_ctx = ssh_hmac_start(macalg->alg)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ mac->key_len = mac->mac_len = ssh_hmac_bytes(macalg->alg);
} else {
- mac->mac_len = macs[which].len / 8;
- mac->key_len = macs[which].key_len / 8;
+ mac->mac_len = macalg->len / 8;
+ mac->key_len = macalg->key_len / 8;
mac->umac_ctx = NULL;
}
- if (macs[which].truncatebits != 0)
- mac->mac_len = macs[which].truncatebits / 8;
+ if (macalg->truncatebits != 0)
+ mac->mac_len = macalg->truncatebits / 8;
+ mac->etm = macalg->etm;
+ return 0;
}
int
-mac_setup(Mac *mac, char *name)
+mac_setup(struct sshmac *mac, char *name)
{
- int i;
-
- for (i = 0; macs[i].name; i++) {
- if (strcmp(name, macs[i].name) == 0) {
- if (mac != NULL)
- mac_setup_by_id(mac, i);
- debug2("mac_setup: found %s", name);
- return (0);
- }
+ const struct macalg *m;
+
+ for (m = macs; m->name != NULL; m++) {
+ if (strcmp(name, m->name) != 0)
+ continue;
+ if (mac != NULL)
+ return mac_setup_by_alg(mac, m);
+ return 0;
}
- debug2("mac_setup: unknown %s", name);
- return (-1);
+ return SSH_ERR_INVALID_ARGUMENT;
}
int
-mac_init(Mac *mac)
+mac_init(struct sshmac *mac)
{
if (mac->key == NULL)
- fatal("mac_init: no key");
+ return SSH_ERR_INVALID_ARGUMENT;
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);
+ case SSH_DIGEST:
+ if (mac->hmac_ctx == NULL ||
+ ssh_hmac_init(mac->hmac_ctx, mac->key, mac->key_len) < 0)
+ return SSH_ERR_INVALID_ARGUMENT;
return 0;
case SSH_UMAC:
- mac->umac_ctx = umac_new(mac->key);
+ if ((mac->umac_ctx = umac_new(mac->key)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ return 0;
+ case SSH_UMAC128:
+ if ((mac->umac_ctx = umac128_new(mac->key)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
return 0;
default:
- return -1;
+ return SSH_ERR_INVALID_ARGUMENT;
}
}
-u_char *
-mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
+int
+mac_compute(struct sshmac *mac, u_int32_t seqno, const u_char *data, int datalen,
+ u_char *digest, size_t dlen)
{
- static u_char m[EVP_MAX_MD_SIZE];
- u_char b[4], nonce[8];
+ static union {
+ u_char m[SSH_DIGEST_MAX_LENGTH];
+ u_int64_t for_align;
+ } u;
+ u_char b[4];
+ u_char nonce[8];
- if (mac->mac_len > sizeof(m))
- fatal("mac_compute: mac too long %u %lu",
- mac->mac_len, (u_long)sizeof(m));
+ if (mac->mac_len > sizeof(u))
+ return SSH_ERR_INTERNAL_ERROR;
switch (mac->type) {
- case SSH_EVP:
+ case SSH_DIGEST:
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);
+ if (ssh_hmac_init(mac->hmac_ctx, NULL, 0) < 0 ||
+ ssh_hmac_update(mac->hmac_ctx, b, sizeof(b)) < 0 ||
+ ssh_hmac_update(mac->hmac_ctx, data, datalen) < 0 ||
+ ssh_hmac_final(mac->hmac_ctx, u.m, sizeof(u.m)) < 0)
+ return SSH_ERR_LIBCRYPTO_ERROR;
break;
case SSH_UMAC:
- put_u64(nonce, seqno);
+ POKE_U64(nonce, seqno);
umac_update(mac->umac_ctx, data, datalen);
- umac_final(mac->umac_ctx, m, nonce);
+ umac_final(mac->umac_ctx, u.m, nonce);
+ break;
+ case SSH_UMAC128:
+ put_u64(nonce, seqno);
+ umac128_update(mac->umac_ctx, data, datalen);
+ umac128_final(mac->umac_ctx, u.m, nonce);
break;
default:
- fatal("mac_compute: unknown MAC type");
+ return SSH_ERR_INVALID_ARGUMENT;
+ }
+ if (digest != NULL) {
+ if (dlen > mac->mac_len)
+ dlen = mac->mac_len;
+ memcpy(digest, u.m, dlen);
}
- return (m);
+ return 0;
}
void
-mac_clear(Mac *mac)
+mac_clear(struct sshmac *mac)
{
if (mac->type == SSH_UMAC) {
if (mac->umac_ctx != NULL)
umac_delete(mac->umac_ctx);
- } else if (mac->evp_md != NULL)
- HMAC_cleanup(&mac->evp_ctx);
- mac->evp_md = NULL;
+ } else if (mac->type == SSH_UMAC128) {
+ if (mac->umac_ctx != NULL)
+ umac128_delete(mac->umac_ctx);
+ } else if (mac->hmac_ctx != NULL)
+ ssh_hmac_free(mac->hmac_ctx);
+ mac->hmac_ctx = NULL;
mac->umac_ctx = NULL;
}
char *maclist, *cp, *p;
if (names == NULL || strcmp(names, "") == 0)
- return (0);
- maclist = cp = xstrdup(names);
+ return 0;
+ if ((maclist = cp = strdup(names)) == NULL)
+ return 0;
for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
(p = strsep(&cp, MAC_SEP))) {
if (mac_setup(NULL, p) < 0) {
- debug("bad mac %s [%s]", p, names);
- xfree(maclist);
- return (0);
- } else {
- debug3("mac ok: %s [%s]", p, names);
+ free(maclist);
+ return 0;
}
}
- debug3("macs ok: [%s]", names);
- xfree(maclist);
- return (1);
+ free(maclist);
+ return 1;
}
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