Merge remote-tracking branch 'upstream-public/pr/1439' into development-proposed
diff --git a/ChangeLog b/ChangeLog
index ec8cc99..0d079c8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,8 @@
resumption of the session).
* Verify results of RSA private key operations to defend
against Bellcore glitch attack.
+ * Fix a buffer overread in ssl_parse_server_key_exchange() that could cause
+ a crash on invalid input.
Features
* Extend PKCS#8 interface by introducing support for the entire SHA
@@ -55,6 +57,8 @@
* Log correct number of ciphersuites used in Client Hello message. #918
* Fix X509 CRT parsing that would potentially accept an invalid tag when
parsing the subject alternative names.
+ * Fix a possible arithmetic overflow in ssl_parse_server_key_exchange()
+ that could cause a key exchange to fail on valid data.
Changes
* Fix tag lengths and value ranges in the documentation of CCM encryption.
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 5367fdd..fc90f86 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2479,10 +2479,18 @@
/*
* 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;
- if( end != p + sig_len )
+ if( p != end - sig_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,