Commit 87a595e5 authored by Richard Levitte's avatar Richard Levitte
Browse files

Refactor DTLS cookie generation and verification 



DTLS cookie generation and verification were exact copies of each
other save the last few lines.  This refactors them to avoid code
copying.

Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
parent 7ab09630

apps/s_cb.c

+11 −66
Original line number Diff line number Diff line
@@ -736,8 +736,8 @@ void tlsext_cb(SSL *s, int client_server, int type, 
int generate_cookie_callback(SSL *ssl, unsigned char *cookie,

                             unsigned int *cookie_len)

{

    unsigned char *buffer, result[EVP_MAX_MD_SIZE];

    unsigned int length, resultlength;

    unsigned char *buffer;

    unsigned int length;

    union {

        struct sockaddr sa;

        struct sockaddr_in s4;
@@ -797,78 +797,23 @@ int generate_cookie_callback(SSL *ssl, unsigned char *cookie, 


    /* Calculate HMAC of buffer using the secret */

    HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,

         buffer, length, result, &resultlength);

         buffer, length, cookie, cookie_len);

    OPENSSL_free(buffer);



    memcpy(cookie, result, resultlength);

    *cookie_len = resultlength;



    return 1;

}



int verify_cookie_callback(SSL *ssl, const unsigned char *cookie,

                           unsigned int cookie_len)

{

    unsigned char *buffer, result[EVP_MAX_MD_SIZE];

    unsigned int length, resultlength;

    union {

        struct sockaddr sa;

        struct sockaddr_in s4;

#if OPENSSL_USE_IPV6

        struct sockaddr_in6 s6;

#endif

    } peer;



    /* If secret isn't initialized yet, the cookie can't be valid */

    if (!cookie_initialized)

        return 0;



    /* Read peer information */

    (void)BIO_dgram_get_peer(SSL_get_rbio(ssl), &peer);



    /* Create buffer with peer's address and port */

    length = 0;

    switch (peer.sa.sa_family) {

    case AF_INET:

        length += sizeof(struct in_addr);

        length += sizeof(peer.s4.sin_port);

        break;

#if OPENSSL_USE_IPV6

    case AF_INET6:

        length += sizeof(struct in6_addr);

        length += sizeof(peer.s6.sin6_port);

        break;

#endif

    default:

        OPENSSL_assert(0);

        break;

    }

    buffer = app_malloc(length, "cookie verify buffer");



    switch (peer.sa.sa_family) {

    case AF_INET:

        memcpy(buffer, &peer.s4.sin_port, sizeof(peer.s4.sin_port));

        memcpy(buffer + sizeof(peer.s4.sin_port),

               &peer.s4.sin_addr, sizeof(struct in_addr));

        break;

#if OPENSSL_USE_IPV6

    case AF_INET6:

        memcpy(buffer, &peer.s6.sin6_port, sizeof(peer.s6.sin6_port));

        memcpy(buffer + sizeof(peer.s6.sin6_port),

               &peer.s6.sin6_addr, sizeof(struct in6_addr));

        break;

#endif

    default:

        OPENSSL_assert(0);

        break;

    }



    /* Calculate HMAC of buffer using the secret */

    HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,

         buffer, length, result, &resultlength);

    OPENSSL_free(buffer);



    if (cookie_len == resultlength

    unsigned char result[EVP_MAX_MD_SIZE];

    unsigned int resultlength;



    /* Note: we check cookie_initialized because if it's not,

     * it cannot be valid */

    if (cookie_initialized

        && generate_cookie_callback(ssl, result, &resultlength)

        && cookie_len == resultlength

        && memcmp(result, cookie, resultlength) == 0)

        return 1;