Correct buffer size check
Further in the code the next field from the binary buffer is read. The
check contained an off by one error.
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 5367fdd..c96c812 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2662,7 +2662,17 @@
cert_type_len = buf[mbedtls_ssl_hs_hdr_len( ssl )];
n = cert_type_len;
- if( ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
+ /*
+ * In the subsequent code there are two paths that make read from buf:
+ * * the length of the signature algorithms field (if minor version of
+ * SSL is 3),
+ * * distinguished name length otherwise.
+ * Both reach at most the index:
+ * ...hdr_len + 2 + n,
+ * therefore the buffer length at this point must be greater than that
+ * regardless of the actual code path.
+ */
+ if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
