Fix buffer overflow in TLS 1.2 ClientKeyExchange parsing
Fix a buffer overflow in TLS 1.2 ClientKeyExchange parsing. When
MBEDTLS_USE_PSA_CRYPTO is enabled, the length of the public key in an ECDH
or ECDHE key exchange was not validated. This could result in an overflow of
handshake->xxdh_psa_peerkey, overwriting further data in the handshake
structure or further on the heap.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index d2143ac..ed2fbd1 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -3734,6 +3734,11 @@
}
/* Store peer's ECDH public key. */
+ MBEDTLS_SSL_DEBUG_MSG(3, ("data_len=%zu sizeof(handshake->xxdh_psa_peerkey)=%zu", data_len, sizeof(handshake->xxdh_psa_peerkey)));
+ if (data_len > sizeof(handshake->xxdh_psa_peerkey)) {
+ MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid data length"));
+ return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
+ }
memcpy(handshake->xxdh_psa_peerkey, p, data_len);
handshake->xxdh_psa_peerkey_len = data_len;