commit a1098f81c252b317ad34ea978aea2bc47760b215
author Krzysztof Stachowiak <krzysiek.stachowiak@gmail.com> Tue Mar 13 11:28:49 2018 +0100
committer Krzysztof Stachowiak <krzysiek.stachowiak@gmail.com> Tue Mar 13 11:28:49 2018 +0100
tree 50cffbe99c32094a13f1e8d58cfe52f2850bfd91
parent 469b8829479f031172e24eedfd473eac0782830c

Add bounds check before signature length read

library/ssl_cli.c

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 2534346..279a127 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2478,6 +2478,14 @@
         /*
          * Read signature
          */
+
+        if( p > end - 2 )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+            return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
+        }
         sig_len = ( p[0] << 8 ) | p[1];
         p += 2;