encrypt_packet_tls13: added explicit check on iv_size boundstmp-check-iv-size

Although there are no ciphers defined for TLS1.3 which would overflow
the assumed bound, an explicit check is necessary to avoid that code
be a liability in future updates.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/cipher.c b/lib/cipher.c
index 3d999de8a6..3ea1cb1bb2 100644
--- a/lib/cipher.c
+++ b/lib/cipher.c
@@ -448,6 +448,9 @@ encrypt_packet_tls13(gnutls_session_t session,
 		return plain->size;
 	}
 
+	if (unlikely(iv_size < 8))
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
 	memcpy(nonce, params->write.iv, iv_size);
 	memxor(&nonce[iv_size-8], UINT64DATA(params->write.sequence_number), 8);