commit 031132c297e54cbc20404a0bf8de6ed863196399
author John Baldwin <jhb@FreeBSD.org> Mon Mar 07 16:55:18 2022 -0800
committer Tomas Mraz <tomas@openssl.org> Wed Apr 06 13:15:27 2022 +0200
tree 0a89dedeca4b2b6ca95bb1af7cf82e5836c6178a
parent 85773128d0e80cd8dcc772a6931d385b8cf4acd1

KTLS: Add using_ktls helper variable in ssl3_get_record().

When KTLS receive is enabled, pending data may still be present due to
read ahead.  This data must still be processed the same as records
received without KTLS.  To ease readability (especially in
consideration of additional checks which will be added for TLS 1.3),
add a helper variable 'using_ktls' that is true when the KTLS receive
path is being used to receive a record.

Co-authored-by: Dmitry Podgorny <pasis.ua@gmail.com>

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17942)

ssl/record/ssl3_record.c

diff --git a/ssl/record/ssl3_record.c b/ssl/record/ssl3_record.c
index 5534814..8eb9497 100644
--- a/ssl/record/ssl3_record.c
+++ b/ssl/record/ssl3_record.c
@@ -185,18 +185,23 @@
     int imac_size;
     size_t num_recs = 0, max_recs, j;
     PACKET pkt, sslv2pkt;
-    int is_ktls_left;
+    int using_ktls;
     SSL_MAC_BUF *macbufs = NULL;
     int ret = -1;
 
     rr = RECORD_LAYER_get_rrec(&s->rlayer);
     rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
-    is_ktls_left = (SSL3_BUFFER_get_left(rbuf) > 0);
     max_recs = s->max_pipelines;
     if (max_recs == 0)
         max_recs = 1;
     sess = s->session;
 
+    /*
+     * KTLS reads full records. If there is any data left,
+     * then it is from before enabling ktls.
+     */
+    using_ktls = BIO_get_ktls_recv(s->rbio) && SSL3_BUFFER_get_left(rbuf) == 0;
+
     do {
         thisrr = &rr[num_recs];
 
@@ -409,7 +414,7 @@
 #endif
 
             /* KTLS may use all of the buffer */
-            if (BIO_get_ktls_recv(s->rbio) && !is_ktls_left)
+            if (using_ktls)
                 len = SSL3_BUFFER_get_left(rbuf);
 
             if (thisrr->length > len) {
@@ -518,11 +523,7 @@
         return 1;
     }
 
-    /*
-     * KTLS reads full records. If there is any data left,
-     * then it is from before enabling ktls
-     */
-    if (BIO_get_ktls_recv(s->rbio) && !is_ktls_left)
+    if (using_ktls)
         goto skip_decryption;
 
     if (s->read_hash != NULL) {
@@ -723,8 +724,7 @@
          * Therefore we have to rely on KTLS to check the plaintext length
          * limit in the kernel.
          */
-        if (thisrr->length > SSL3_RT_MAX_PLAIN_LENGTH
-                && (!BIO_get_ktls_recv(s->rbio) || is_ktls_left)) {
+        if (thisrr->length > SSL3_RT_MAX_PLAIN_LENGTH && !using_ktls) {
             SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_R_DATA_LENGTH_TOO_LONG);
             goto end;
         }