1 files changed, 80 insertions, 50 deletions

diff --git a/kex.c b/kex.c
index f9e7a9c09..1ec278245 100644
--- a/kex.c
+++ b/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.88 2013/01/08 18:49:04 markus Exp $ */
+/* $OpenBSD: kex.c,v 1.91 2013/05/17 00:13:13 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
@@ -66,6 +66,69 @@ extern const EVP_MD *evp_ssh_sha256(void);
 static void kex_kexinit_finish(Kex *);
 static void kex_choose_conf(Kex *);
 
+struct kexalg {
+        char *name;
+        int type;
+        int ec_nid;
+        const EVP_MD *(*mdfunc)(void);
+};
+static const struct kexalg kexalgs[] = {
+        { KEX_DH1, KEX_DH_GRP1_SHA1, 0, EVP_sha1 },
+        { KEX_DH14, KEX_DH_GRP14_SHA1, 0, EVP_sha1 },
+        { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, EVP_sha1 },
+#ifdef HAVE_EVP_SHA256
+        { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, EVP_sha256 },
+#endif
+#ifdef OPENSSL_HAS_ECC
+        { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2, NID_X9_62_prime256v1, EVP_sha256 },
+        { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1, EVP_sha384 },
+        { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1, EVP_sha512 },
+#endif
+        { NULL, -1, -1, NULL},
+};
+static const struct kexalg kexalg_prefixes[] = {
+#ifdef GSSAPI
+        { KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, EVP_sha1 },
+        { KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, EVP_sha1 },
+        { KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, EVP_sha1 },
+#endif
+        { NULL, -1, -1, NULL },
+};
+
+char *
+kex_alg_list(void)
+{
+        char *ret = NULL;
+        size_t nlen, rlen = 0;
+        const struct kexalg *k;
+
+        for (k = kexalgs; k->name != NULL; k++) {
+                if (ret != NULL)
+                        ret[rlen++] = '\n';
+                nlen = strlen(k->name);
+                ret = xrealloc(ret, 1, rlen + nlen + 2);
+                memcpy(ret + rlen, k->name, nlen + 1);
+                rlen += nlen;
+        }
+        return ret;
+}
+
+static const struct kexalg *
+kex_alg_by_name(const char *name)
+{
+        const struct kexalg *k;
+
+        for (k = kexalgs; k->name != NULL; k++) {
+                if (strcmp(k->name, name) == 0)
+                        return k;
+        }
+        for (k = kexalg_prefixes; k->name != NULL; k++) {
+                if (strncmp(k->name, name, strlen(k->name)) == 0)
+                        return k;
+        }
+        return NULL;
+}
+
 /* Validate KEX method name list */
 int
 kex_names_valid(const char *names)
@@ -77,20 +140,14 @@ kex_names_valid(const char *names)
         s = cp = xstrdup(names);
         for ((p = strsep(&cp, ",")); p && *p != '\0';
             (p = strsep(&cp, ","))) {
-                if (strcmp(p, KEX_DHGEX_SHA256) != 0 &&
-                    strcmp(p, KEX_DHGEX_SHA1) != 0 &&
-                    strcmp(p, KEX_DH14) != 0 &&
-                    strcmp(p, KEX_DH1) != 0 &&
-                    (strncmp(p, KEX_ECDH_SHA2_STEM,
-                    sizeof(KEX_ECDH_SHA2_STEM) - 1) != 0 ||
-                    kex_ecdh_name_to_nid(p) == -1)) {
+                if (kex_alg_by_name(p) == NULL) {
                         error("Unsupported KEX algorithm \"%.100s\"", p);
-                        xfree(s);
+                        free(s);
                         return 0;
                 }
         }
         debug3("kex names ok: [%s]", names);
-        xfree(s);
+        free(s);
         return 1;
 }
 
@@ -150,8 +207,8 @@ kex_prop_free(char **proposal)
         u_int i;
 
         for (i = 0; i < PROPOSAL_MAX; i++)
-                xfree(proposal[i]);
-        xfree(proposal);
+                free(proposal[i]);
+        free(proposal);
 }
 
 /* ARGSUSED */
@@ -188,7 +245,7 @@ kex_finish(Kex *kex)
         buffer_clear(&kex->peer);
         /* buffer_clear(&kex->my); */
         kex->flags &= ~KEX_INIT_SENT;
-        xfree(kex->name);
+        free(kex->name);
         kex->name = NULL;
 }
 
@@ -245,7 +302,7 @@ kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
         for (i = 0; i < KEX_COOKIE_LEN; i++)
                 packet_get_char();
         for (i = 0; i < PROPOSAL_MAX; i++)
-                xfree(packet_get_string(NULL));
+                free(packet_get_string(NULL));
         /*
          * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
          * KEX method has the server move first, but a server might be using
@@ -352,43 +409,16 @@ choose_comp(Comp *comp, char *client, char *server)
 static void
 choose_kex(Kex *k, char *client, char *server)
 {
+        const struct kexalg *kexalg;
+
         k->name = match_list(client, server, NULL);
         if (k->name == NULL)
                 fatal("Unable to negotiate a key exchange method");
-        if (strcmp(k->name, KEX_DH1) == 0) {
-                k->kex_type = KEX_DH_GRP1_SHA1;
-                k->evp_md = EVP_sha1();
-        } else if (strcmp(k->name, KEX_DH14) == 0) {
-                k->kex_type = KEX_DH_GRP14_SHA1;
-                k->evp_md = EVP_sha1();
-        } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
-                k->kex_type = KEX_DH_GEX_SHA1;
-                k->evp_md = EVP_sha1();
-#if OPENSSL_VERSION_NUMBER >= 0x00907000L
-        } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
-                k->kex_type = KEX_DH_GEX_SHA256;
-                k->evp_md = evp_ssh_sha256();
-        } else if (strncmp(k->name, KEX_ECDH_SHA2_STEM,
-            sizeof(KEX_ECDH_SHA2_STEM) - 1) == 0) {
-                k->kex_type = KEX_ECDH_SHA2;
-                k->evp_md = kex_ecdh_name_to_evpmd(k->name);
-#endif
-#ifdef GSSAPI
-        } else if (strncmp(k->name, KEX_GSS_GEX_SHA1_ID,
-            sizeof(KEX_GSS_GEX_SHA1_ID) - 1) == 0) {
-                k->kex_type = KEX_GSS_GEX_SHA1;
-                k->evp_md = EVP_sha1();
-        } else if (strncmp(k->name, KEX_GSS_GRP1_SHA1_ID,
-            sizeof(KEX_GSS_GRP1_SHA1_ID) - 1) == 0) {
-                k->kex_type = KEX_GSS_GRP1_SHA1;
-                k->evp_md = EVP_sha1();
-        } else if (strncmp(k->name, KEX_GSS_GRP14_SHA1_ID,
-            sizeof(KEX_GSS_GRP14_SHA1_ID) - 1) == 0) {
-                k->kex_type = KEX_GSS_GRP14_SHA1;
-                k->evp_md = EVP_sha1();
-#endif
-        } else
-                fatal("bad kex alg %s", k->name);
+        if ((kexalg = kex_alg_by_name(k->name)) == NULL)
+                fatal("unsupported kex alg %s", k->name);
+        k->kex_type = kexalg->type;
+        k->evp_md = kexalg->mdfunc();
+        k->ec_nid = kexalg->ec_nid;
 }
 
 static void
@@ -400,7 +430,7 @@ choose_hostkeyalg(Kex *k, char *client, char *server)
         k->hostkey_type = key_type_from_name(hostkeyalg);
         if (k->hostkey_type == KEY_UNSPEC)
                 fatal("bad hostkey alg '%s'", hostkeyalg);
-        xfree(hostkeyalg);
+        free(hostkeyalg);
 }
 
 static int
@@ -454,7 +484,7 @@ kex_choose_conf(Kex *kex)
                 roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL);
                 if (roaming) {
                         kex->roaming = 1;
-                        xfree(roaming);
+                        free(roaming);
                 }
         }