Add a missing buffer size check
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index a854745..7da59f0 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2700,9 +2700,32 @@
size_t sig_alg_len = ( ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 1 + n] << 8 )
| ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n] ) );
#if defined(MBEDTLS_DEBUG_C)
- unsigned char* sig_alg = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n;
+ unsigned char* sig_alg;
size_t i;
+#endif
+ /*
+ * The farthes access in buf is in the loop few lines below:
+ * sig_alg[i + 1],
+ * where:
+ * sig_alg = buf + ...hdr_len + 3 + n,
+ * max(i) = sig_alg_len - 1.
+ * Therefore the farthest access is:
+ * buf[...hdr_len + 3 + n + sig_alg_len - 1 + 1],
+ * which reduces to:
+ * buf[...hdr_len + 3 + n + sig_alg_len],
+ * which is one less than we need the buf to be.
+ */
+ if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n + sig_alg_len )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+ return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
+ }
+
+#if defined(MBEDTLS_DEBUG_C)
+ sig_alg = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n;
for( i = 0; i < sig_alg_len; i += 2 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "Supported Signature Algorithm found: %d"