Add guard to out_left to avoid negative values
return error when f_send return a value greater than out_left
diff --git a/ChangeLog b/ChangeLog
index 708ecad..d82600c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,8 @@
Contributed by Mathieu Briand.
* Fix typo in a comment ctr_drbg.c. Contributed by Paul Sokolovsky.
* Remove support for the library reference configuration for picocoin.
+ * Add guard to validate that out_left can not be negative. Raised by
+ samoconnor in #1245.
= mbed TLS 2.7.0 branch released 2018-02-03
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 617dedb..1de5eaa 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2469,6 +2469,12 @@
if( ret <= 0 )
return( ret );
+ if( (size_t)ret > ssl->out_left )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "f_send returned value greater than out left size" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
ssl->out_left -= ret;
}
