Fix SRP ciphersuite DoS vulnerability.

If a client attempted to use an SRP ciphersuite and it had not been
set up correctly it would crash with a null pointer read. A malicious
server could exploit this in a DoS attack.

Thanks to Joonas Kuorilehto and Riku Hietamäki from Codenomicon
for reporting this issue.

CVE-2014-5139
Reviewed-by: Tim Hudson <tjh@openssl.org>

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index df05f788e921bcfe77a4ab620fd05ebab2a94cbb..0aba7e5e0a2bd0170d408ca2bf101ce58f6a2ea0 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -954,6 +954,15 @@ int ssl3_get_server_hello(SSL *s)
                SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_WRONG_CIPHER_RETURNED);
                goto f_err;
                }
+#ifndef OPENSSL_NO_SRP
+       if (((c->algorithm_mkey & SSL_kSRP) || (c->algorithm_auth & SSL_aSRP)) &&
+                   !(s->srp_ctx.srp_Mask & SSL_kSRP))
+               {
+               al=SSL_AD_ILLEGAL_PARAMETER;
+               SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_WRONG_CIPHER_RETURNED);
+               goto f_err;
+               }
+#endif /* OPENSSL_NO_SRP */
        p+=ssl_put_cipher_by_char(s,NULL,NULL);
 
        sk=ssl_get_ciphers_by_id(s);

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index ef6258ca9f06ea89034317e63e8245c8fb035020..82a2c801292c56cc140da2916e10af378419b007 100644 (file)
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1406,6 +1406,11 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
                    s->psk_client_callback == NULL)
                        continue;
 #endif /* OPENSSL_NO_PSK */
+#ifndef OPENSSL_NO_SRP
+               if (((c->algorithm_mkey & SSL_kSRP) || (c->algorithm_auth & SSL_aSRP)) &&
+                   !(s->srp_ctx.srp_Mask & SSL_kSRP))
+                   continue;
+#endif /* OPENSSL_NO_SRP */
                j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);
                p+=j;
                }