Sanity check record length before skipping explicit IV in TLS 1.2, 1.1 and

DTLS to fix DoS attack.

Thanks to Codenomicon for discovering this issue using Fuzz-o-Matic
fuzzing as a service testing platform.
(CVE-2012-2333)

3 files changed, 11 insertions, 1 deletions

diff --git a/CHANGES b/CHANGES
index 8425bb37ea..2656e6616e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -292,6 +292,14 @@
  
  Changes between 1.0.1b and 1.0.1c [xx XXX xxxx]
 
+  *) Sanity check record length before skipping explicit IV in TLS
+     1.2, 1.1 and DTLS to avoid DoS attack.
+
+     Thanks to Codenomicon for discovering this issue using Fuzz-o-Matic
+     fuzzing as a service testing platform.
+     (CVE-2012-2333)
+     [Steve Henson]
+
   *) Initialise tkeylen properly when encrypting CMS messages.
      Thanks to Solar Designer of Openwall for reporting this issue.
      [Steve Henson]
diff --git a/ssl/d1_enc.c b/ssl/d1_enc.c
index becbab91c2..07a5e97ce5 100644
--- a/ssl/d1_enc.c
+++ b/ssl/d1_enc.c
@@ -260,7 +260,7 @@ int dtls1_enc(SSL *s, int send)
 				}
 			/* TLS 1.0 does not bound the number of padding bytes by the block size.
 			 * All of them must have value 'padding_length'. */
-			if (i > (int)rec->length)
+			if (i + bs > (int)rec->length)
 				{
 				/* Incorrect padding. SSLerr() and ssl3_alert are done
 				 * by caller: we don't want to reveal whether this is
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 201ca9ad6d..f7bdeb3b9d 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -889,6 +889,8 @@ int tls1_enc(SSL *s, int send)
 			if (s->version >= TLS1_1_VERSION
 				&& EVP_CIPHER_CTX_mode(ds) == EVP_CIPH_CBC_MODE)
 				{
+				if (bs > (int)rec->length)
+					return -1;
 				rec->data += bs;    /* skip the explicit IV */
 				rec->input += bs;
 				rec->length -= bs;