Commit e1e588ac authored by Matt Caswell's avatar Matt Caswell
Browse files

Tidy up tls_process_key_exchange() 



After the refactor of tls_process_key_exchange(), this commit tidies up
some loose ends.

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
parent ff74aeb1

ssl/statem/statem_clnt.c

+41 −32
Original line number Diff line number Diff line
@@ -1574,29 +1574,17 @@ static int tls_process_ske_ecdhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al) 


MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)

{

    EVP_MD_CTX *md_ctx;

    int al = -1;

    long alg_k, alg_a;

    long alg_k;

    EVP_PKEY *pkey = NULL;

    PACKET save_param_start, signature;



    md_ctx = EVP_MD_CTX_new();

    if (md_ctx == NULL) {

        al = SSL_AD_INTERNAL_ERROR;

        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);

        goto f_err;

    }



    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;



    save_param_start = *pkt;



#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)

    EVP_PKEY_free(s->s3->peer_tmp);

    s->s3->peer_tmp = NULL;

#endif



    alg_a = s->s3->tmp.new_cipher->algorithm_auth;



    if (alg_k & SSL_PSK) {

        if (!tls_process_ske_psk_preamble(s, pkt, &al))
@@ -1617,7 +1605,7 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
    } else if (alg_k) {

        al = SSL_AD_UNEXPECTED_MESSAGE;

        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_UNEXPECTED_MESSAGE);

        goto f_err;

        goto err;

    }



    /* if it was signed, check the signature */
@@ -1625,6 +1613,8 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
        PACKET params;

        int maxsig;

        const EVP_MD *md = NULL;

        EVP_MD_CTX *md_ctx;



        /*

         * |pkt| now points to the beginning of the signature, so the difference

         * equals the length of the parameters.
@@ -1634,21 +1624,24 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
                                   PACKET_remaining(pkt))) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);

            goto f_err;

            goto err;

        }



        if (SSL_USE_SIGALGS(s)) {

            const unsigned char *sigalgs;

            int rv;

            if (!PACKET_get_bytes(pkt, &sigalgs, 2)) {

                al = SSL_AD_DECODE_ERROR;

                SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);

                goto f_err;

                goto err;

            }

            rv = tls12_check_peer_sigalg(&md, s, sigalgs, pkey);

            if (rv == -1)

            if (rv == -1) {

                al = SSL_AD_INTERNAL_ERROR;

                goto err;

            } else if (rv == 0) {

                al = SSL_AD_DECODE_ERROR;

                goto err;

            else if (rv == 0) {

                goto f_err;

            }

#ifdef SSL_DEBUG

            fprintf(stderr, "USING TLSv1.2 HASH %s\n", EVP_MD_name(md));
@@ -1661,13 +1654,15 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 


        if (!PACKET_get_length_prefixed_2(pkt, &signature)

            || PACKET_remaining(pkt) != 0) {

            al = SSL_AD_DECODE_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);

            goto f_err;

            goto err;

        }

        maxsig = EVP_PKEY_size(pkey);

        if (maxsig < 0) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);

            goto f_err;

            goto err;

        }



        /*
@@ -1675,9 +1670,18 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
         */

        if (PACKET_remaining(&signature) > (size_t)maxsig) {

            /* wrong packet length */

            al = SSL_AD_DECODE_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_WRONG_SIGNATURE_LENGTH);

            goto f_err;

            goto err;

        }



        md_ctx = EVP_MD_CTX_new();

        if (md_ctx == NULL) {

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);

            goto err;

        }



        if (EVP_VerifyInit_ex(md_ctx, md, NULL) <= 0

                || EVP_VerifyUpdate(md_ctx, &(s->s3->client_random[0]),

                                    SSL3_RANDOM_SIZE) <= 0
@@ -1685,41 +1689,46 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt) 
                                    SSL3_RANDOM_SIZE) <= 0

                || EVP_VerifyUpdate(md_ctx, PACKET_data(&params),

                                    PACKET_remaining(&params)) <= 0) {

            EVP_MD_CTX_free(md_ctx);

            al = SSL_AD_INTERNAL_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);

            goto f_err;

            goto err;

        }

        if (EVP_VerifyFinal(md_ctx, PACKET_data(&signature),

                            PACKET_remaining(&signature), pkey) <= 0) {

            /* bad signature */

            EVP_MD_CTX_free(md_ctx);

            al = SSL_AD_DECRYPT_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_SIGNATURE);

            goto f_err;

            goto err;

        }

        EVP_MD_CTX_free(md_ctx);

    } else {

        /* aNULL, aSRP or PSK do not need public keys */

        if (!(alg_a & (SSL_aNULL | SSL_aSRP)) && !(alg_k & SSL_PSK)) {

        if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP))

                && !(alg_k & SSL_PSK)) {

            /* Might be wrong key type, check it */

            if (ssl3_check_cert_and_algorithm(s))

            if (ssl3_check_cert_and_algorithm(s)) {

                /* Otherwise this shouldn't happen */

                al = SSL_AD_INTERNAL_ERROR;

                SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);

            } else {

                al = SSL_AD_DECODE_ERROR;

            }

            goto err;

        }

        /* still data left over */

        if (PACKET_remaining(pkt) != 0) {

            al = SSL_AD_DECODE_ERROR;

            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_EXTRA_DATA_IN_MESSAGE);

            goto f_err;

            goto err;

        }

    }

    EVP_MD_CTX_free(md_ctx);



    return MSG_PROCESS_CONTINUE_READING;

 f_err:

    if (al == -1)

        al = SSL_AD_DECODE_ERROR;

 err:

    if (al != -1)

        ssl3_send_alert(s, SSL3_AL_FATAL, al);

    EVP_MD_CTX_free(md_ctx);

    ossl_statem_set_error(s);

    return MSG_PROCESS_ERROR;

}