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)

diff --git a/CHANGES b/CHANGES
index 8425bb37eaf87c465ee1e420104acca0637cf157..2656e6616e0f45297f8c6166e0b75405be295736 100644 (file)
--- 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 becbab91c219617452c9bacda251dadaf93331ee..07a5e97ce5cda574154f7a91b3906e765a1692f7 100644 (file)
--- 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 201ca9ad6de20299a52870bf85257357fb1ae43b..f7bdeb3b9dbac573ff9539dc8638aab45b8df432 100644 (file)
--- 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;