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IABSD.fr/src/lib/libssl/t1_lib.c
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/* $OpenBSD: t1_lib.c,v 1.204 2025/01/18 14:17:05 tb Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ /* ==================================================================== * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.openssl.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include <stdio.h> #include <openssl/evp.h> #include <openssl/hmac.h> #include <openssl/objects.h> #include <openssl/ocsp.h> #include "bytestring.h" #include "ssl_local.h" #include "ssl_sigalgs.h" #include "ssl_tlsext.h" static int tls_decrypt_ticket(SSL *s, CBS *ticket, int *alert, SSL_SESSION **psess); int tls1_new(SSL *s) { if (!ssl3_new(s)) return 0; s->method->ssl_clear(s); return 1; } void tls1_free(SSL *s) { if (s == NULL) return; free(s->tlsext_session_ticket); ssl3_free(s); } void tls1_clear(SSL *s) { ssl3_clear(s); s->version = s->method->version; } struct supported_group { int nid; int bits; }; /* * Supported groups (formerly known as named curves) * https://www.iana.org/assignments/tls-parameters/#tls-parameters-8 */ static const struct supported_group nid_list[] = { [1] = { .nid = NID_sect163k1, .bits = 80, }, [2] = { .nid = NID_sect163r1, .bits = 80, }, [3] = { .nid = NID_sect163r2, .bits = 80, }, [4] = { .nid = NID_sect193r1, .bits = 80, }, [5] = { .nid = NID_sect193r2, .bits = 80, }, [6] = { .nid = NID_sect233k1, .bits = 112, }, [7] = { .nid = NID_sect233r1, .bits = 112, }, [8] = { .nid = NID_sect239k1, .bits = 112, }, [9] = { .nid = NID_sect283k1, .bits = 128, }, [10] = { .nid = NID_sect283r1, .bits = 128, }, [11] = { .nid = NID_sect409k1, .bits = 192, }, [12] = { .nid = NID_sect409r1, .bits = 192, }, [13] = { .nid = NID_sect571k1, .bits = 256, }, [14] = { .nid = NID_sect571r1, .bits = 256, }, [15] = { .nid = NID_secp160k1, .bits = 80, }, [16] = { .nid = NID_secp160r1, .bits = 80, }, [17] = { .nid = NID_secp160r2, .bits = 80, }, [18] = { .nid = NID_secp192k1, .bits = 80, }, [19] = { .nid = NID_X9_62_prime192v1, /* aka secp192r1 */ .bits = 80, }, [20] = { .nid = NID_secp224k1, .bits = 112, }, [21] = { .nid = NID_secp224r1, .bits = 112, }, [22] = { .nid = NID_secp256k1, .bits = 128, }, [23] = { .nid = NID_X9_62_prime256v1, /* aka secp256r1 */ .bits = 128, }, [24] = { .nid = NID_secp384r1, .bits = 192, }, [25] = { .nid = NID_secp521r1, .bits = 256, }, [26] = { .nid = NID_brainpoolP256r1, .bits = 128, }, [27] = { .nid = NID_brainpoolP384r1, .bits = 192, }, [28] = { .nid = NID_brainpoolP512r1, .bits = 256, }, [29] = { .nid = NID_X25519, .bits = 128, }, }; #define NID_LIST_LEN (sizeof(nid_list) / sizeof(nid_list[0])) #if 0 static const uint8_t ecformats_list[] = { TLSEXT_ECPOINTFORMAT_uncompressed, TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime, TLSEXT_ECPOINTFORMAT_ansiX962_compressed_char2 }; #endif static const uint8_t ecformats_default[] = { TLSEXT_ECPOINTFORMAT_uncompressed, }; #if 0 static const uint16_t ecgroups_list[] = { 29, /* X25519 (29) */ 14, /* sect571r1 (14) */ 13, /* sect571k1 (13) */ 25, /* secp521r1 (25) */ 28, /* brainpoolP512r1 (28) */ 11, /* sect409k1 (11) */ 12, /* sect409r1 (12) */ 27, /* brainpoolP384r1 (27) */ 24, /* secp384r1 (24) */ 9, /* sect283k1 (9) */ 10, /* sect283r1 (10) */ 26, /* brainpoolP256r1 (26) */ 22, /* secp256k1 (22) */ 23, /* secp256r1 (23) */ 8, /* sect239k1 (8) */ 6, /* sect233k1 (6) */ 7, /* sect233r1 (7) */ 20, /* secp224k1 (20) */ 21, /* secp224r1 (21) */ 4, /* sect193r1 (4) */ 5, /* sect193r2 (5) */ 18, /* secp192k1 (18) */ 19, /* secp192r1 (19) */ 1, /* sect163k1 (1) */ 2, /* sect163r1 (2) */ 3, /* sect163r2 (3) */ 15, /* secp160k1 (15) */ 16, /* secp160r1 (16) */ 17, /* secp160r2 (17) */ }; #endif static const uint16_t ecgroups_client_default[] = { 29, /* X25519 (29) */ 23, /* secp256r1 (23) */ 24, /* secp384r1 (24) */ 25, /* secp521r1 (25) */ }; static const uint16_t ecgroups_server_default[] = { 29, /* X25519 (29) */ 23, /* secp256r1 (23) */ 24, /* secp384r1 (24) */ }; int tls1_ec_group_id2nid(uint16_t group_id, int *out_nid) { int nid; if (group_id >= NID_LIST_LEN) return 0; if ((nid = nid_list[group_id].nid) == 0) return 0; *out_nid = nid; return 1; } int tls1_ec_group_id2bits(uint16_t group_id, int *out_bits) { int bits; if (group_id >= NID_LIST_LEN) return 0; if ((bits = nid_list[group_id].bits) == 0) return 0; *out_bits = bits; return 1; } int tls1_ec_nid2group_id(int nid, uint16_t *out_group_id) { uint16_t group_id; if (nid == 0) return 0; for (group_id = 0; group_id < NID_LIST_LEN; group_id++) { if (nid_list[group_id].nid == nid) { *out_group_id = group_id; return 1; } } return 0; } /* * Return the appropriate format list. If client_formats is non-zero, return * the client/session formats. Otherwise return the custom format list if one * exists, or the default formats if a custom list has not been specified. */ void tls1_get_formatlist(const SSL *s, int client_formats, const uint8_t **pformats, size_t *pformatslen) { if (client_formats != 0) { *pformats = s->session->tlsext_ecpointformatlist; *pformatslen = s->session->tlsext_ecpointformatlist_length; return; } *pformats = s->tlsext_ecpointformatlist; *pformatslen = s->tlsext_ecpointformatlist_length; if (*pformats == NULL) { *pformats = ecformats_default; *pformatslen = sizeof(ecformats_default); } } /* * Return the appropriate group list. If client_groups is non-zero, return * the client/session groups. Otherwise return the custom group list if one * exists, or the default groups if a custom list has not been specified. */ void tls1_get_group_list(const SSL *s, int client_groups, const uint16_t **pgroups, size_t *pgroupslen) { if (client_groups != 0) { *pgroups = s->session->tlsext_supportedgroups; *pgroupslen = s->session->tlsext_supportedgroups_length; return; } *pgroups = s->tlsext_supportedgroups; *pgroupslen = s->tlsext_supportedgroups_length; if (*pgroups != NULL) return; if (!s->server) { *pgroups = ecgroups_client_default; *pgroupslen = sizeof(ecgroups_client_default) / 2; } else { *pgroups = ecgroups_server_default; *pgroupslen = sizeof(ecgroups_server_default) / 2; } } static int tls1_get_group_lists(const SSL *ssl, const uint16_t **pref, size_t *preflen, const uint16_t **supp, size_t *supplen) { unsigned long server_pref; /* Cannot do anything on the client side. */ if (!ssl->server) return 0; server_pref = (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE); tls1_get_group_list(ssl, (server_pref == 0), pref, preflen); tls1_get_group_list(ssl, (server_pref != 0), supp, supplen); return 1; } static int tls1_group_id_present(uint16_t group_id, const uint16_t *list, size_t list_len) { size_t i; for (i = 0; i < list_len; i++) { if (group_id == list[i]) return 1; } return 0; } int tls1_count_shared_groups(const SSL *ssl, size_t *out_count) { size_t count, preflen, supplen, i; const uint16_t *pref, *supp; if (!tls1_get_group_lists(ssl, &pref, &preflen, &supp, &supplen)) return 0; count = 0; for (i = 0; i < preflen; i++) { if (!tls1_group_id_present(pref[i], supp, supplen)) continue; if (!ssl_security_shared_group(ssl, pref[i])) continue; count++; } *out_count = count; return 1; } static int tls1_group_by_index(const SSL *ssl, size_t n, int *out_nid, int (*ssl_security_fn)(const SSL *, uint16_t)) { size_t count, preflen, supplen, i; const uint16_t *pref, *supp; if (!tls1_get_group_lists(ssl, &pref, &preflen, &supp, &supplen)) return 0; count = 0; for (i = 0; i < preflen; i++) { if (!tls1_group_id_present(pref[i], supp, supplen)) continue; if (!ssl_security_fn(ssl, pref[i])) continue; if (count++ == n) return tls1_ec_group_id2nid(pref[i], out_nid); } return 0; } int tls1_get_shared_group_by_index(const SSL *ssl, size_t index, int *out_nid) { return tls1_group_by_index(ssl, index, out_nid, ssl_security_shared_group); } int tls1_get_supported_group(const SSL *ssl, int *out_nid) { return tls1_group_by_index(ssl, 0, out_nid, ssl_security_supported_group); } int tls1_set_groups(uint16_t **out_group_ids, size_t *out_group_ids_len, const int *groups, size_t ngroups) { uint16_t *group_ids; size_t i; if ((group_ids = calloc(ngroups, sizeof(uint16_t))) == NULL) return 0; for (i = 0; i < ngroups; i++) { if (!tls1_ec_nid2group_id(groups[i], &group_ids[i])) { free(group_ids); return 0; } } free(*out_group_ids); *out_group_ids = group_ids; *out_group_ids_len = ngroups; return 1; } int tls1_set_group_list(uint16_t **out_group_ids, size_t *out_group_ids_len, const char *groups) { uint16_t *new_group_ids, *group_ids = NULL; size_t ngroups = 0; char *gs, *p, *q; int nid; if ((gs = strdup(groups)) == NULL) return 0; q = gs; while ((p = strsep(&q, ":")) != NULL) { nid = OBJ_sn2nid(p); if (nid == NID_undef) nid = OBJ_ln2nid(p); if (nid == NID_undef) nid = EC_curve_nist2nid(p); if (nid == NID_undef) goto err; if ((new_group_ids = reallocarray(group_ids, ngroups + 1, sizeof(uint16_t))) == NULL) goto err; group_ids = new_group_ids; if (!tls1_ec_nid2group_id(nid, &group_ids[ngroups])) goto err; ngroups++; } free(gs); free(*out_group_ids); *out_group_ids = group_ids; *out_group_ids_len = ngroups; return 1; err: free(gs); free(group_ids); return 0; } /* Check that a group is one of our preferences. */ int tls1_check_group(SSL *s, uint16_t group_id) { const uint16_t *groups; size_t groupslen, i; tls1_get_group_list(s, 0, &groups, &groupslen); for (i = 0; i < groupslen; i++) { if (!ssl_security_supported_group(s, groups[i])) continue; if (groups[i] == group_id) return 1; } return 0; } /* For an EC key set TLS ID and required compression based on parameters. */ static int tls1_set_ec_id(uint16_t *group_id, uint8_t *comp_id, EC_KEY *ec) { const EC_GROUP *group; int nid; if ((group = EC_KEY_get0_group(ec)) == NULL) return 0; /* Determine group ID. */ nid = EC_GROUP_get_curve_name(group); if (!tls1_ec_nid2group_id(nid, group_id)) return 0; /* Specify the compression identifier. */ if (EC_KEY_get0_public_key(ec) == NULL) return 0; *comp_id = TLSEXT_ECPOINTFORMAT_uncompressed; if (EC_KEY_get_conv_form(ec) == POINT_CONVERSION_COMPRESSED) { *comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime; } return 1; } /* Check that an EC key is compatible with extensions. */ static int tls1_check_ec_key(SSL *s, const uint16_t group_id, const uint8_t comp_id) { size_t groupslen, formatslen, i; const uint16_t *groups; const uint8_t *formats; /* * Check point formats extension if present, otherwise everything * is supported (see RFC4492). */ tls1_get_formatlist(s, 1, &formats, &formatslen); if (formats != NULL) { for (i = 0; i < formatslen; i++) { if (formats[i] == comp_id) break; } if (i == formatslen) return 0; } /* * Check group list if present, otherwise everything is supported. */ tls1_get_group_list(s, 1, &groups, &groupslen); if (groups != NULL) { for (i = 0; i < groupslen; i++) { if (groups[i] == group_id) break; } if (i == groupslen) return 0; } return 1; } /* Check EC server key is compatible with client extensions. */ int tls1_check_ec_server_key(SSL *s) { SSL_CERT_PKEY *cpk = s->cert->pkeys + SSL_PKEY_ECC; uint16_t group_id; uint8_t comp_id; EC_KEY *eckey; EVP_PKEY *pkey; if (cpk->x509 == NULL || cpk->privatekey == NULL) return 0; if ((pkey = X509_get0_pubkey(cpk->x509)) == NULL) return 0; if ((eckey = EVP_PKEY_get0_EC_KEY(pkey)) == NULL) return 0; if (!tls1_set_ec_id(&group_id, &comp_id, eckey)) return 0; return tls1_check_ec_key(s, group_id, comp_id); } int ssl_check_clienthello_tlsext_early(SSL *s) { int ret = SSL_TLSEXT_ERR_NOACK; int al = SSL_AD_UNRECOGNIZED_NAME; /* The handling of the ECPointFormats extension is done elsewhere, namely in * ssl3_choose_cipher in s3_lib.c. */ /* The handling of the EllipticCurves extension is done elsewhere, namely in * ssl3_choose_cipher in s3_lib.c. */ if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) ret = s->ctx->tlsext_servername_callback(s, &al, s->ctx->tlsext_servername_arg); else if (s->initial_ctx != NULL && s->initial_ctx->tlsext_servername_callback != 0) ret = s->initial_ctx->tlsext_servername_callback(s, &al, s->initial_ctx->tlsext_servername_arg); switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(s, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(s, SSL3_AL_WARNING, al); return 1; case SSL_TLSEXT_ERR_NOACK: default: return 1; } } int ssl_check_clienthello_tlsext_late(SSL *s) { int ret = SSL_TLSEXT_ERR_OK; int al = 0; /* XXX gcc3 */ /* If status request then ask callback what to do. * Note: this must be called after servername callbacks in case * the certificate has changed, and must be called after the cipher * has been chosen because this may influence which certificate is sent */ if ((s->tlsext_status_type != -1) && s->ctx && s->ctx->tlsext_status_cb) { int r; SSL_CERT_PKEY *certpkey; certpkey = ssl_get_server_send_pkey(s); /* If no certificate can't return certificate status */ if (certpkey == NULL) { s->tlsext_status_expected = 0; return 1; } /* Set current certificate to one we will use so * SSL_get_certificate et al can pick it up. */ s->cert->key = certpkey; r = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg); switch (r) { /* We don't want to send a status request response */ case SSL_TLSEXT_ERR_NOACK: s->tlsext_status_expected = 0; break; /* status request response should be sent */ case SSL_TLSEXT_ERR_OK: if (s->tlsext_ocsp_resp) s->tlsext_status_expected = 1; else s->tlsext_status_expected = 0; break; /* something bad happened */ case SSL_TLSEXT_ERR_ALERT_FATAL: ret = SSL_TLSEXT_ERR_ALERT_FATAL; al = SSL_AD_INTERNAL_ERROR; goto err; } } else s->tlsext_status_expected = 0; err: switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(s, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(s, SSL3_AL_WARNING, al); return 1; default: return 1; } } int ssl_check_serverhello_tlsext(SSL *s) { int ret = SSL_TLSEXT_ERR_NOACK; int al = SSL_AD_UNRECOGNIZED_NAME; ret = SSL_TLSEXT_ERR_OK; if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) ret = s->ctx->tlsext_servername_callback(s, &al, s->ctx->tlsext_servername_arg); else if (s->initial_ctx != NULL && s->initial_ctx->tlsext_servername_callback != 0) ret = s->initial_ctx->tlsext_servername_callback(s, &al, s->initial_ctx->tlsext_servername_arg); /* If we've requested certificate status and we wont get one * tell the callback */ if ((s->tlsext_status_type != -1) && !(s->tlsext_status_expected) && s->ctx && s->ctx->tlsext_status_cb) { int r; free(s->tlsext_ocsp_resp); s->tlsext_ocsp_resp = NULL; s->tlsext_ocsp_resp_len = 0; r = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg); if (r == 0) { al = SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE; ret = SSL_TLSEXT_ERR_ALERT_FATAL; } if (r < 0) { al = SSL_AD_INTERNAL_ERROR; ret = SSL_TLSEXT_ERR_ALERT_FATAL; } } switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(s, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(s, SSL3_AL_WARNING, al); return 1; case SSL_TLSEXT_ERR_NOACK: default: return 1; } } /* 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. * * ext_block: a CBS for the ClientHello extensions block. * 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: * TLS1_TICKET_FATAL_ERROR: error from parsing or decrypting the ticket. * TLS1_TICKET_NONE: no ticket was found (or was ignored, based on settings). * TLS1_TICKET_EMPTY: a zero length extension was found, indicating that the * client supports session tickets but doesn't currently have one to offer. * TLS1_TICKET_NOT_DECRYPTED: either s->tls_session_secret_cb was * set, or a ticket was offered but couldn't be decrypted because of a * non-fatal error. * TLS1_TICKET_DECRYPTED: 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, CBS *ext_block, int *alert, SSL_SESSION **ret) { CBS extensions, ext_data; uint16_t ext_type = 0; s->tlsext_ticket_expected = 0; *ret = NULL; /* * If tickets disabled behave as if no ticket present to permit stateful * resumption. */ if (SSL_get_options(s) & SSL_OP_NO_TICKET) return TLS1_TICKET_NONE; /* * An empty extensions block is valid, but obviously does not contain * a session ticket. */ if (CBS_len(ext_block) == 0) return TLS1_TICKET_NONE; if (!CBS_get_u16_length_prefixed(ext_block, &extensions)) { *alert = SSL_AD_DECODE_ERROR; return TLS1_TICKET_FATAL_ERROR; } while (CBS_len(&extensions) > 0) { if (!CBS_get_u16(&extensions, &ext_type) || !CBS_get_u16_length_prefixed(&extensions, &ext_data)) { *alert = SSL_AD_DECODE_ERROR; return TLS1_TICKET_FATAL_ERROR; } if (ext_type == TLSEXT_TYPE_session_ticket) break; } if (ext_type != TLSEXT_TYPE_session_ticket) return TLS1_TICKET_NONE; if (CBS_len(&ext_data) == 0) { /* * The client will accept a ticket but does not currently * have one. */ s->tlsext_ticket_expected = 1; return TLS1_TICKET_EMPTY; } if (s->tls_session_secret_cb != NULL) { /* * Indicate that the ticket could not be decrypted rather than * generating the session from ticket now, trigger abbreviated * handshake based on external mechanism to calculate the master * secret later. */ return TLS1_TICKET_NOT_DECRYPTED; } return tls_decrypt_ticket(s, &ext_data, alert, ret); } /* tls_decrypt_ticket attempts to decrypt a session ticket. * * ticket: a CBS containing the body of the session ticket extension. * psess: (output) on return, if a ticket was decrypted, then this is set to * point to the resulting session. * * Returns: * TLS1_TICKET_FATAL_ERROR: error from parsing or decrypting the ticket. * TLS1_TICKET_NOT_DECRYPTED: the ticket couldn't be decrypted. * TLS1_TICKET_DECRYPTED: a ticket was decrypted and *psess was set. */ static int tls_decrypt_ticket(SSL *s, CBS *ticket, int *alert, SSL_SESSION **psess) { CBS ticket_name, ticket_iv, ticket_encdata, ticket_hmac; SSL_SESSION *sess = NULL; unsigned char *sdec = NULL; size_t sdec_len = 0; const unsigned char *p; unsigned char hmac[EVP_MAX_MD_SIZE]; HMAC_CTX *hctx = NULL; EVP_CIPHER_CTX *cctx = NULL; SSL_CTX *tctx = s->initial_ctx; int slen, hlen, iv_len; int alert_desc = SSL_AD_INTERNAL_ERROR; int ret = TLS1_TICKET_FATAL_ERROR; *psess = NULL; if (!CBS_get_bytes(ticket, &ticket_name, 16)) goto derr; /* * Initialize session ticket encryption and HMAC contexts. */ if ((cctx = EVP_CIPHER_CTX_new()) == NULL) goto err; if ((hctx = HMAC_CTX_new()) == NULL) goto err; if (tctx->tlsext_ticket_key_cb != NULL) { int rv; /* * The API guarantees EVP_MAX_IV_LENGTH bytes of space for * the iv to tlsext_ticket_key_cb(). Since the total space * required for a session cookie is never less than this, * this check isn't too strict. The exact check comes later. */ if (CBS_len(ticket) < EVP_MAX_IV_LENGTH) goto derr; if ((rv = tctx->tlsext_ticket_key_cb(s, (unsigned char *)CBS_data(&ticket_name), (unsigned char *)CBS_data(ticket), cctx, hctx, 0)) < 0) goto err; if (rv == 0) goto derr; if (rv == 2) { /* Renew ticket. */ s->tlsext_ticket_expected = 1; } if ((iv_len = EVP_CIPHER_CTX_iv_length(cctx)) < 0) goto err; /* * Now that the cipher context is initialised, we can extract * the IV since its length is known. */ if (!CBS_get_bytes(ticket, &ticket_iv, iv_len)) goto derr; } else { /* Check that the key name matches. */ if (!CBS_mem_equal(&ticket_name, tctx->tlsext_tick_key_name, sizeof(tctx->tlsext_tick_key_name))) goto derr; if ((iv_len = EVP_CIPHER_iv_length(EVP_aes_128_cbc())) < 0) goto err; if (!CBS_get_bytes(ticket, &ticket_iv, iv_len)) goto derr; if (!EVP_DecryptInit_ex(cctx, EVP_aes_128_cbc(), NULL, tctx->tlsext_tick_aes_key, CBS_data(&ticket_iv))) goto err; if (!HMAC_Init_ex(hctx, tctx->tlsext_tick_hmac_key, sizeof(tctx->tlsext_tick_hmac_key), EVP_sha256(), NULL)) goto err; } /* * Attempt to process session ticket. */ if ((hlen = HMAC_size(hctx)) < 0) goto err; if (hlen > CBS_len(ticket)) goto derr; if (!CBS_get_bytes(ticket, &ticket_encdata, CBS_len(ticket) - hlen)) goto derr; if (!CBS_get_bytes(ticket, &ticket_hmac, hlen)) goto derr; if (CBS_len(ticket) != 0) { alert_desc = SSL_AD_DECODE_ERROR; goto err; } /* Check HMAC of encrypted ticket. */ if (HMAC_Update(hctx, CBS_data(&ticket_name), CBS_len(&ticket_name)) <= 0) goto err; if (HMAC_Update(hctx, CBS_data(&ticket_iv), CBS_len(&ticket_iv)) <= 0) goto err; if (HMAC_Update(hctx, CBS_data(&ticket_encdata), CBS_len(&ticket_encdata)) <= 0) goto err; if (HMAC_Final(hctx, hmac, &hlen) <= 0) goto err; if (!CBS_mem_equal(&ticket_hmac, hmac, hlen)) goto derr; /* Attempt to decrypt session data. */ sdec_len = CBS_len(&ticket_encdata); if ((sdec = calloc(1, sdec_len)) == NULL) goto err; if (EVP_DecryptUpdate(cctx, sdec, &slen, CBS_data(&ticket_encdata), CBS_len(&ticket_encdata)) <= 0) goto derr; if (EVP_DecryptFinal_ex(cctx, sdec + slen, &hlen) <= 0) goto derr; slen += hlen; /* * For session parse failures, indicate that we need to send a new * ticket. */ p = sdec; if ((sess = d2i_SSL_SESSION(NULL, &p, slen)) == NULL) goto derr; *psess = sess; sess = NULL; ret = TLS1_TICKET_DECRYPTED; goto done; derr: ERR_clear_error(); s->tlsext_ticket_expected = 1; ret = TLS1_TICKET_NOT_DECRYPTED; goto done; err: *alert = alert_desc; ret = TLS1_TICKET_FATAL_ERROR; goto done; done: freezero(sdec, sdec_len); EVP_CIPHER_CTX_free(cctx); HMAC_CTX_free(hctx); SSL_SESSION_free(sess); return ret; }