Commit c31dbed7 authored by Matt Caswell's avatar Matt Caswell
Browse files

Fix a mem leak in NPN handling 



If a server sent multiple NPN extensions in a single ClientHello then a
mem leak can occur. This will only happen where the client has requested
NPN in the first place. It does not occur during renegotiation. Therefore
the maximum that could be leaked in a single connection with a malicious
server is 64k (the maximum size of the ServerHello extensions section). As
this is client side, only occurs if NPN has been requested and does not
occur during renegotiation this is unlikely to be exploitable.

Issue reported by Shi Lei.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
parent ba881d3b

ssl/t1_lib.c

+5 −0
Original line number Diff line number Diff line
@@ -2394,6 +2394,11 @@ static int ssl_scan_serverhello_tlsext(SSL *s, PACKET *pkt, int *al) 
                *al = TLS1_AD_INTERNAL_ERROR;

                return 0;

            }

            /*

             * Could be non-NULL if server has sent multiple NPN extensions in

             * a single Serverhello

             */

            OPENSSL_free(s->next_proto_negotiated);

            s->next_proto_negotiated = OPENSSL_malloc(selected_len);

            if (s->next_proto_negotiated == NULL) {

                *al = TLS1_AD_INTERNAL_ERROR;