1 files changed, 54 insertions, 29 deletions

diff --git a/mac.c b/mac.c
index 3f2dc6f2a..c4dfb501d 100644
--- a/mac.c
+++ b/mac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mac.c,v 1.21 2012/12/11 22:51:45 sthen Exp $ */
+/* $OpenBSD: mac.c,v 1.24 2013/06/03 00:03:18 dtucker Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -50,7 +50,7 @@
 #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);
@@ -58,7 +58,9 @@ struct {
         int             key_len;        /* just for UMAC */
         int             len;            /* just for UMAC */
         int             etm;            /* Encrypt-then-MAC */
-} macs[] = {
+};
+
+static const struct macalg macs[] = {
         /* Encrypt-and-MAC (encrypt-and-authenticate) variants */
         { "hmac-sha1",                          SSH_EVP, EVP_sha1, 0, 0, 0, 0 },
         { "hmac-sha1-96",                       SSH_EVP, EVP_sha1, 96, 0, 0, 0 },
@@ -89,38 +91,58 @@ struct {
         { NULL,                                 0, NULL, 0, 0, 0, 0 }
 };
 
+/* Returns a comma-separated list of supported MACs. */
+char *
+mac_alg_list(void)
+{
+        char *ret = NULL;
+        size_t nlen, rlen = 0;
+        const struct macalg *m;
+
+        for (m = macs; m->name != NULL; m++) {
+                if (ret != NULL)
+                        ret[rlen++] = '\n';
+                nlen = strlen(m->name);
+                ret = xrealloc(ret, 1, rlen + nlen + 2);
+                memcpy(ret + rlen, m->name, nlen + 1);
+                rlen += nlen;
+        }
+        return ret;
+}
+
 static void
-mac_setup_by_id(Mac *mac, int which)
+mac_setup_by_alg(Mac *mac, const struct macalg *macalg)
 {
         int evp_len;
-        mac->type = macs[which].type;
+
+        mac->type = macalg->type;
         if (mac->type == SSH_EVP) {
-                mac->evp_md = (*macs[which].mdfunc)();
+                mac->evp_md = macalg->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 {
-                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;
-        mac->etm = macs[which].etm;
+        if (macalg->truncatebits != 0)
+                mac->mac_len = macalg->truncatebits / 8;
+        mac->etm = macalg->etm;
 }
 
 int
 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_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)
+                        mac_setup_by_alg(mac, m);
+                debug2("mac_setup: found %s", name);
+                return (0);
         }
         debug2("mac_setup: unknown %s", name);
         return (-1);
@@ -152,12 +174,15 @@ mac_init(Mac *mac)
 u_char *
 mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
 {
-        static u_char m[EVP_MAX_MD_SIZE];
+        static union {
+                u_char m[EVP_MAX_MD_SIZE];
+                u_int64_t for_align;
+        } u;
         u_char b[4], nonce[8];
 
-        if (mac->mac_len > sizeof(m))
+        if (mac->mac_len > sizeof(u))
                 fatal("mac_compute: mac too long %u %lu",
-                    mac->mac_len, (u_long)sizeof(m));
+                    mac->mac_len, (u_long)sizeof(u));
 
         switch (mac->type) {
         case SSH_EVP:
@@ -166,22 +191,22 @@ mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
                 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);
+                HMAC_Final(&mac->evp_ctx, u.m, NULL);
                 break;
         case SSH_UMAC:
                 put_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, m, nonce);
+                umac128_final(mac->umac_ctx, u.m, nonce);
                 break;
         default:
                 fatal("mac_compute: unknown MAC type");
         }
-        return (m);
+        return (u.m);
 }
 
 void
@@ -213,13 +238,13 @@ mac_valid(const char *names)
             (p = strsep(&cp, MAC_SEP))) {
                 if (mac_setup(NULL, p) < 0) {
                         debug("bad mac %s [%s]", p, names);
-                        xfree(maclist);
+                        free(maclist);
                         return (0);
                 } else {
                         debug3("mac ok: %s [%s]", p, names);
                 }
         }
         debug3("macs ok: [%s]", names);
-        xfree(maclist);
+        free(maclist);
         return (1);
 }