From 80b6d97585511931d7e5d1cbf24bd19f34d88bda Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Fri, 20 Dec 2013 15:26:50 +0000 Subject: [PATCH] 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) --- ssl/d1_both.c | 6 ++++++ ssl/t1_enc.c | 17 +++++++++++------ 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/ssl/d1_both.c b/ssl/d1_both.c index f7947bd98..f0c596294 100644 --- 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 9eac36aa0..78ce5256e 100644 --- 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) {