Commit ee85fc1d authored by Matt Caswell's avatar Matt Caswell
Browse files

Don't set peer_tmp until we have finished constructing it 



If we fail halfway through constructing the peer_tmp EVP_PKEY but we have
already stored it in s->s3->peer_tmp then if anything tries to use it then
it will likely fail. This was causing s_client to core dump in the
sslskewith0p test. s_client was trying to print out the connection
parameters that it had negotiated so far. Arguably s_client should not do
that if the connection has failed...but given it is existing functionality
it's easier to fix libssl.

Reviewed-by: default avatarViktor Dukhovni <viktor@openssl.org>
parent 48c1e15c

ssl/statem/statem_clnt.c

+36 −27
Original line number Diff line number Diff line
@@ -1525,9 +1525,10 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
#ifndef OPENSSL_NO_DH

    else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {

        PACKET prime, generator, pub_key;

        EVP_PKEY *peer_tmp = NULL;



        DH *dh;

        BIGNUM *p, *g, *bnpub_key;

        DH *dh = NULL;

        BIGNUM *p = NULL, *g = NULL, *bnpub_key = NULL;



        if (!PACKET_get_length_prefixed_2(pkt, &prime)

            || !PACKET_get_length_prefixed_2(pkt, &generator)
@@ -1536,19 +1537,13 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
            goto f_err;

        }



        s->s3->peer_tmp = EVP_PKEY_new();

        peer_tmp = EVP_PKEY_new();

        dh = DH_new();



        if (s->s3->peer_tmp == NULL || dh == NULL) {

        if (peer_tmp == NULL || dh == NULL) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);

            DH_free(dh);

            goto err;

        }



        if (EVP_PKEY_assign_DH(s->s3->peer_tmp, dh) == 0) {

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);

            DH_free(dh);

            goto err;

            goto dherr;

        }



        p = BN_bin2bn(PACKET_data(&prime), PACKET_remaining(&prime), NULL);
@@ -1558,39 +1553,53 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
                              NULL);

        if (p == NULL || g == NULL || bnpub_key == NULL) {

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);

            BN_free(p);

            BN_free(g);

            BN_free(bnpub_key);

            goto err;

            goto dherr;

        }



        if (BN_is_zero(p) || BN_is_zero(g) || BN_is_zero(bnpub_key)) {

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_DH_VALUE);

            BN_free(p);

            BN_free(g);

            BN_free(bnpub_key);

            goto f_err;

            goto dherr;

        }



        if (!DH_set0_pqg(dh, p, NULL, g)) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);

            BN_free(p);

            BN_free(g);

            BN_free(bnpub_key);

            goto err;

            goto dherr;

        }



        if (!DH_set0_key(dh, bnpub_key, NULL)) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);

            BN_free(bnpub_key);

            goto err;

            goto dherr;

        }



        if (!ssl_security(s, SSL_SECOP_TMP_DH, DH_security_bits(dh), 0, dh)) {

            al = SSL_AD_HANDSHAKE_FAILURE;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_DH_KEY_TOO_SMALL);

            goto f_err;

            goto dherr;

        }



        if (EVP_PKEY_assign_DH(peer_tmp, dh) == 0) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);

            goto dherr;

        }



        s->s3->peer_tmp = peer_tmp;



        goto dhend;

 dherr:

        BN_free(p);

        BN_free(g);

        BN_free(bnpub_key);

        DH_free(dh);

        EVP_PKEY_free(peer_tmp);

        goto f_err;

 dhend:

        /*

         * FIXME: This makes assumptions about which ciphersuites come with

         * public keys. We should have a less ad-hoc way of doing this

         */

        if (alg_a & (SSL_aRSA|SSL_aDSS))

            pkey = X509_get0_pubkey(s->session->peer);

        /* else anonymous DH, so no certificate or pkey. */