Fix DTLS retransmission from previous session.

For DTLS we might need to retransmit messages from the previous session
so keep a copy of write context in DTLS retransmission buffers instead
of replacing it after sending CCS. CVE-2013-6450.

diff --git a/CHANGES b/CHANGES
index cfaebba26ab67f8962aea1cc4517efb82d104e99..173be2465e855b10ab994d889498ac5244067097 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 1.0.1e and 1.0.1f [xx XXX xxxx]
 
+  *) Keep original DTLS digest and encryption contexts in retransmission
+     structures so we can use the previous session parameters if they need
+     to be resent. (CVE-2013-6450)
+     [Steve Henson]
+
   *) Add option SSL_OP_SAFARI_ECDHE_ECDSA_BUG (part of SSL_OP_ALL) which
      avoids preferring ECDHE-ECDSA ciphers when the client appears to be
      Safari on OS X.  Safari on OS X 10.8..10.8.3 advertises support for

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 65ec0018ae64baa175f37ece77de8f5883ff516d..7a5596a6b373aeabbd6d8d674f0e20b1618c5012 100644 (file)
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -214,6 +214,12 @@ dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
 static void
 dtls1_hm_fragment_free(hm_fragment *frag)
        {
+
+       if (frag->msg_header.is_ccs)
+               {
+               EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
+               EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
+               }
        if (frag->fragment) OPENSSL_free(frag->fragment);
        if (frag->reassembly) OPENSSL_free(frag->reassembly);
        OPENSSL_free(frag);

diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 96ce9a72458d8b98a1cca001665761b79a2ac63b..e48590774815b4d9a4df6d485a3bf99257a4e406 100644 (file)
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -621,6 +621,8 @@ extern SSL3_ENC_METHOD TLSv1_enc_data;
 extern SSL3_ENC_METHOD SSLv3_enc_data;
 extern SSL3_ENC_METHOD DTLSv1_enc_data;
 
+#define SSL_IS_DTLS(s) (s->method->version == DTLS1_VERSION)
+
 #define IMPLEMENT_tls_meth_func(version, func_name, s_accept, s_connect, \
                                s_get_meth) \
 const SSL_METHOD *func_name(void)  \

diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 72015f5aad67c56869ad0484df19eff628eca653..56db83430630b0dc2e67e302bc5d484046979de2 100644 (file)
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -414,15 +414,20 @@ int tls1_change_cipher_state(SSL *s, int which)
                        s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
                        else
                        s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
-               if (s->enc_write_ctx != NULL)
+               if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s))
                        reuse_dd = 1;
-               else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
+               else if ((s->enc_write_ctx=EVP_CIPHER_CTX_new()) == NULL)
                        goto err;
-               else
-                       /* make sure it's intialized in case we exit later with an error */
-                       EVP_CIPHER_CTX_init(s->enc_write_ctx);
                dd= s->enc_write_ctx;
-               mac_ctx = ssl_replace_hash(&s->write_hash,NULL);
+               if (SSL_IS_DTLS(s))
+                       {
+                       mac_ctx = EVP_MD_CTX_create();
+                       if (!mac_ctx)
+                               goto err;
+                       s->write_hash = mac_ctx;
+                       }
+               else
+                       mac_ctx = ssl_replace_hash(&s->write_hash,NULL);
 #ifndef OPENSSL_NO_COMP
                if (s->compress != NULL)
                        {