diff options
Diffstat (limited to 'ssl/t1_lib.c')
| -rw-r--r-- | ssl/t1_lib.c | 154 |
1 files changed, 103 insertions, 51 deletions
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c index cfb3b54565..93869fa83b 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -1838,26 +1838,56 @@ int ssl_check_serverhello_tlsext(SSL *s) } } -/* Since the server cache lookup is done early on in the processing of client - * hello and other operations depend on the result we need to handle any TLS - * session ticket extension at the same time. +/* Since the server cache lookup is done early on in the processing of the + * ClientHello, and other operations depend on the result, we need to handle + * any TLS session ticket extension at the same time. + * + * session_id: points at the session ID in the ClientHello. This code will + * read past the end of this in order to parse out the session ticket + * extension, if any. + * len: the length of the session ID. + * limit: a pointer to the first byte after the ClientHello. + * ret: (output) on return, if a ticket was decrypted, then this is set to + * point to the resulting session. + * + * If s->tls_session_secret_cb is set then we are expecting a pre-shared key + * ciphersuite, in which case we have no use for session tickets and one will + * never be decrypted, nor will s->tlsext_ticket_expected be set to 1. + * + * Returns: + * -1: fatal error, either from parsing or decrypting the ticket. + * 0: no ticket was found (or was ignored, based on settings). + * 1: a zero length extension was found, indicating that the client supports + * session tickets but doesn't currently have one to offer. + * 2: either s->tls_session_secret_cb was set, or a ticket was offered but + * couldn't be decrypted because of a non-fatal error. + * 3: a ticket was successfully decrypted and *ret was set. + * + * Side effects: + * Sets s->tlsext_ticket_expected to 1 if the server will have to issue + * a new session ticket to the client because the client indicated support + * (and s->tls_session_secret_cb is NULL) but the client either doesn't have + * a session ticket or we couldn't use the one it gave us, or if + * s->ctx->tlsext_ticket_key_cb asked to renew the client's ticket. + * Otherwise, s->tlsext_ticket_expected is set to 0. */ - int tls1_process_ticket(SSL *s, unsigned char *session_id, int len, - const unsigned char *limit, SSL_SESSION **ret) + const unsigned char *limit, SSL_SESSION **ret) { /* Point after session ID in client hello */ const unsigned char *p = session_id + len; unsigned short i; + *ret = NULL; + s->tlsext_ticket_expected = 0; + /* If tickets disabled behave as if no ticket present - * to permit stateful resumption. - */ + * to permit stateful resumption. + */ if (SSL_get_options(s) & SSL_OP_NO_TICKET) - return 1; - + return 0; if ((s->version <= SSL3_VERSION) || !limit) - return 1; + return 0; if (p >= limit) return -1; /* Skip past DTLS cookie */ @@ -1880,7 +1910,7 @@ int tls1_process_ticket(SSL *s, unsigned char *session_id, int len, return -1; /* Now at start of extensions */ if ((p + 2) >= limit) - return 1; + return 0; n2s(p, i); while ((p + 4) <= limit) { @@ -1888,39 +1918,61 @@ int tls1_process_ticket(SSL *s, unsigned char *session_id, int len, n2s(p, type); n2s(p, size); if (p + size > limit) - return 1; + return 0; if (type == TLSEXT_TYPE_session_ticket) { - /* If tickets disabled indicate cache miss which will - * trigger a full handshake - */ - if (SSL_get_options(s) & SSL_OP_NO_TICKET) - return 1; - /* If zero length note client will accept a ticket - * and indicate cache miss to trigger full handshake - */ + int r; if (size == 0) { + /* The client will accept a ticket but doesn't + * currently have one. */ s->tlsext_ticket_expected = 1; - return 0; /* Cache miss */ + return 1; } if (s->tls_session_secret_cb) { - /* Indicate cache miss here and instead of - * generating the session from ticket now, - * trigger abbreviated handshake based on - * external mechanism to calculate the master - * secret later. */ - return 0; + /* Indicate that the ticket couldn't be + * decrypted rather than generating the session + * from ticket now, trigger abbreviated + * handshake based on external mechanism to + * calculate the master secret later. */ + return 2; + } + r = tls_decrypt_ticket(s, p, size, session_id, len, ret); + switch (r) + { + case 2: /* ticket couldn't be decrypted */ + s->tlsext_ticket_expected = 1; + return 2; + case 3: /* ticket was decrypted */ + return r; + case 4: /* ticket decrypted but need to renew */ + s->tlsext_ticket_expected = 1; + return 3; + default: /* fatal error */ + return -1; } - return tls_decrypt_ticket(s, p, size, session_id, len, - ret); } p += size; } - return 1; + return 0; } +/* tls_decrypt_ticket attempts to decrypt a session ticket. + * + * etick: points to the body of the session ticket extension. + * eticklen: the length of the session tickets extenion. + * sess_id: points at the session ID. + * sesslen: the length of the session ID. + * psess: (output) on return, if a ticket was decrypted, then this is set to + * point to the resulting session. + * + * Returns: + * -1: fatal error, either from parsing or decrypting the ticket. + * 2: the ticket couldn't be decrypted. + * 3: a ticket was successfully decrypted and *psess was set. + * 4: same as 3, but the ticket needs to be renewed. + */ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, const unsigned char *sess_id, int sesslen, SSL_SESSION **psess) @@ -1935,7 +1987,7 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, SSL_CTX *tctx = s->initial_ctx; /* Need at least keyname + iv + some encrypted data */ if (eticklen < 48) - goto tickerr; + return 2; /* Initialize session ticket encryption and HMAC contexts */ HMAC_CTX_init(&hctx); EVP_CIPHER_CTX_init(&ctx); @@ -1947,7 +1999,7 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, if (rv < 0) return -1; if (rv == 0) - goto tickerr; + return 2; if (rv == 2) renew_ticket = 1; } @@ -1955,15 +2007,15 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, { /* Check key name matches */ if (memcmp(etick, tctx->tlsext_tick_key_name, 16)) - goto tickerr; + return 2; HMAC_Init_ex(&hctx, tctx->tlsext_tick_hmac_key, 16, tlsext_tick_md(), NULL); EVP_DecryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL, tctx->tlsext_tick_aes_key, etick + 16); } /* Attempt to process session ticket, first conduct sanity and - * integrity checks on ticket. - */ + * integrity checks on ticket. + */ mlen = HMAC_size(&hctx); if (mlen < 0) { @@ -1976,7 +2028,7 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, HMAC_Final(&hctx, tick_hmac, NULL); HMAC_CTX_cleanup(&hctx); if (memcmp(tick_hmac, etick + eticklen, mlen)) - goto tickerr; + return 2; /* Attempt to decrypt session data */ /* Move p after IV to start of encrypted ticket, update length */ p = etick + 16 + EVP_CIPHER_CTX_iv_length(&ctx); @@ -1989,33 +2041,33 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen, } EVP_DecryptUpdate(&ctx, sdec, &slen, p, eticklen); if (EVP_DecryptFinal(&ctx, sdec + slen, &mlen) <= 0) - goto tickerr; + return 2; slen += mlen; EVP_CIPHER_CTX_cleanup(&ctx); p = sdec; - + sess = d2i_SSL_SESSION(NULL, &p, slen); OPENSSL_free(sdec); if (sess) { - /* The session ID if non-empty is used by some clients to - * detect that the ticket has been accepted. So we copy it to - * the session structure. If it is empty set length to zero - * as required by standard. - */ + /* The session ID, if non-empty, is used by some clients to + * detect that the ticket has been accepted. So we copy it to + * the session structure. If it is empty set length to zero + * as required by standard. + */ if (sesslen) memcpy(sess->session_id, sess_id, sesslen); sess->session_id_length = sesslen; *psess = sess; - s->tlsext_ticket_expected = renew_ticket; - return 1; + if (renew_ticket) + return 4; + else + return 3; } - /* If session decrypt failure indicate a cache miss and set state to - * send a new ticket - */ - tickerr: - s->tlsext_ticket_expected = 1; - return 0; + ERR_clear_error(); + /* For session parse failure, indicate that we need to send a new + * ticket. */ + return 2; } /* Tables to translate from NIDs to TLS v1.2 ids */ |