Commit d0debc0a authored by Matt Caswell's avatar Matt Caswell
Browse files

Add a timestamp to the cookie 



Reviewed-by: default avatarBen Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4435)
parent c2f9648d

ssl/statem/extensions_srvr.c

+14 −4
Original line number Diff line number Diff line
@@ -17,11 +17,11 @@ 
/*

 * 2 bytes for packet length, 2 bytes for format version, 2 bytes for

 * protocol version, 2 bytes for group id, 2 bytes for cipher id, 1 byte for

 * key_share present flag, 2 bytes for the hashlen, EVP_MAX_MD_SIZE for

 * transcript hash, 1 byte for app cookie length, app cookie length bytes,

 * SHA256_DIGEST_LENGTH bytes for the HMAC of the whole thing.

 * key_share present flag, 4 bytes for timestamp, 2 bytes for the hashlen,

 * EVP_MAX_MD_SIZE for transcript hash, 1 byte for app cookie length, app cookie

 * length bytes, SHA256_DIGEST_LENGTH bytes for the HMAC of the whole thing.

 */

#define MAX_COOKIE_SIZE (2 + 2 + 2 + 2 + 2 + 1 + 2 + EVP_MAX_MD_SIZE + 1 \

#define MAX_COOKIE_SIZE (2 + 2 + 2 + 2 + 2 + 1 + 4 + 2 + EVP_MAX_MD_SIZE + 1 \

                         + SSL_COOKIE_LENGTH + SHA256_DIGEST_LENGTH)



/*
@@ -705,6 +705,7 @@ int tls_parse_ctos_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 
    unsigned char hmac[SHA256_DIGEST_LENGTH];

    unsigned char hrr[MAX_HRR_SIZE];

    size_t rawlen, hmaclen, hrrlen, ciphlen;

    unsigned long tm, now;



    /* Ignore any cookie if we're not set up to verify it */

    if (s->ctx->app_verify_cookie_cb == NULL
@@ -814,6 +815,7 @@ int tls_parse_ctos_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 
    }



    if (!PACKET_get_1(&cookie, &key_share)

            || !PACKET_get_net_4(&cookie, &tm)

            || !PACKET_get_length_prefixed_2(&cookie, &chhash)

            || !PACKET_get_length_prefixed_1(&cookie, &appcookie)

            || PACKET_remaining(&cookie) != SHA256_DIGEST_LENGTH) {
@@ -822,6 +824,13 @@ int tls_parse_ctos_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 
        return 0;

    }



    /* We tolerate a cookie age of up to 10 minutes (= 60 * 10 seconds) */

    now = (unsigned long)time(NULL);

    if (tm > now || (now - tm) > 600) {

        /* Cookie is stale. Ignore it */

        return 1;

    }



    /* Verify the app cookie */

    if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&appcookie),

                                     PACKET_remaining(&appcookie)) == 0) {
@@ -1603,6 +1612,7 @@ EXT_RETURN tls_construct_stoc_cookie(SSL *s, WPACKET *pkt, unsigned int context, 
                                              &ciphlen)

               /* Is there a key_share extension present in this HRR? */

            || !WPACKET_put_bytes_u8(pkt, s->s3->peer_tmp == NULL)

            || !WPACKET_put_bytes_u32(pkt, (unsigned int)time(NULL))

            || !WPACKET_start_sub_packet_u16(pkt)

            || !WPACKET_reserve_bytes(pkt, EVP_MAX_MD_SIZE, &hashval1)) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,