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.
(cherry picked from commit 34628967f1e65dc8f34e000f0f5518e21afbfc7b)

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index f7947bd98817a7b25c728e03ff1dbf1a7831cfe3..f0c5962949e2046f4160eb04302a3b69585e5dcd 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/t1_enc.c b/ssl/t1_enc.c
index 9eac36aa05528c5ef2e66ec7fa75de75733d5e27..78ce5256e32d9a6d21530b6e15bff8110b4b6b0d 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)
                        {