From 20b82b514d81a64f5b240788e5051167456af379 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) --- CHANGES | 5 +++++ ssl/d1_both.c | 6 ++++++ ssl/t1_enc.c | 17 +++++++++++------ 3 files changed, 22 insertions(+), 6 deletions(-) diff --git a/CHANGES b/CHANGES index 2602cfac96..111db939f9 100644 --- a/CHANGES +++ b/CHANGES @@ -273,6 +273,11 @@ Changes between 1.0.1e and 1.0.2 [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] + *) TLS pad extension: draft-agl-tls-padding-02 Workaround for the "TLS hang bug" (see FAQ and PR#2771): if the diff --git a/ssl/d1_both.c b/ssl/d1_both.c index f7947bd988..f0c5962949 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 acc5f21363..0432801b16 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) { -- 2.25.1