[openssl] OpenSSL_1_1_1-stable update

[tmraz at fedoraproject.org]

The branch OpenSSL_1_1_1-stable has been updated
       via  dfbaef60fe2ff95a1bc4362f2c5a39d0cf6f2513 (commit)
      from  218e740f850f77c9f2720d56886eab166d1a6727 (commit)


- Log -----------------------------------------------------------------
commit dfbaef60fe2ff95a1bc4362f2c5a39d0cf6f2513
Author: Simon Cornish <7t9jna402 at sneakemail.com>
Date:   Fri Feb 14 14:16:09 2020 -0800

    Handle max_fragment_length overflow for DTLS
    
    Allow for encryption overhead in early DTLS size check
    and send overflow if validated record is too long
    
    Reviewed-by: Matt Caswell <matt at openssl.org>
    Reviewed-by: Tomas Mraz <tmraz at fedoraproject.org>
    (Merged from https://github.com/openssl/openssl/pull/11096)
    
    (cherry picked from commit cc0663f697b05ed121a728241f0502250429802d)

-----------------------------------------------------------------------

Summary of changes:
 ssl/record/ssl3_record.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/ssl/record/ssl3_record.c b/ssl/record/ssl3_record.c
index 8b43805e81..c4c482e35d 100644
--- a/ssl/record/ssl3_record.c
+++ b/ssl/record/ssl3_record.c
@@ -1610,6 +1610,7 @@ int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap)
     int imac_size;
     size_t mac_size;
     unsigned char md[EVP_MAX_MD_SIZE];
+    size_t max_plain_length = SSL3_RT_MAX_PLAIN_LENGTH;
 
     rr = RECORD_LAYER_get_rrec(&s->rlayer);
     sess = s->session;
@@ -1782,7 +1783,12 @@ int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap)
         }
     }
 
-    if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH) {
+    /* use current Max Fragment Length setting if applicable */
+    if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session))
+        max_plain_length = GET_MAX_FRAGMENT_LENGTH(s->session);
+
+    /* send overflow if the plaintext is too long now it has passed MAC */
+    if (rr->length > max_plain_length) {
         SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
                  SSL_R_DATA_LENGTH_TOO_LONG);
         return 0;
@@ -1926,7 +1932,7 @@ int dtls1_get_record(SSL *s)
 
         /* If received packet overflows own-client Max Fragment Length setting */
         if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
-                && rr->length > GET_MAX_FRAGMENT_LENGTH(s->session)) {
+                && rr->length > GET_MAX_FRAGMENT_LENGTH(s->session) + SSL3_RT_MAX_ENCRYPTED_OVERHEAD) {
             /* record too long, silently discard it */
             rr->length = 0;
             rr->read = 1;