/* $Id$ */ /* * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) * Copyright (C) 2003-2008 Benny Prijono * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #define THIS_FILE "stun_auth.c" /* Duplicate credential */ PJ_DEF(void) pj_stun_auth_cred_dup( pj_pool_t *pool, pj_stun_auth_cred *dst, const pj_stun_auth_cred *src) { dst->type = src->type; switch (src->type) { case PJ_STUN_AUTH_CRED_STATIC: pj_strdup(pool, &dst->data.static_cred.realm, &src->data.static_cred.realm); pj_strdup(pool, &dst->data.static_cred.username, &src->data.static_cred.username); dst->data.static_cred.data_type = src->data.static_cred.data_type; pj_strdup(pool, &dst->data.static_cred.data, &src->data.static_cred.data); pj_strdup(pool, &dst->data.static_cred.nonce, &src->data.static_cred.nonce); break; case PJ_STUN_AUTH_CRED_DYNAMIC: pj_memcpy(&dst->data.dyn_cred, &src->data.dyn_cred, sizeof(src->data.dyn_cred)); break; } } /* * Duplicate request credential. */ PJ_DEF(void) pj_stun_req_cred_info_dup( pj_pool_t *pool, pj_stun_req_cred_info *dst, const pj_stun_req_cred_info *src) { pj_strdup(pool, &dst->realm, &src->realm); pj_strdup(pool, &dst->username, &src->username); pj_strdup(pool, &dst->nonce, &src->nonce); pj_strdup(pool, &dst->auth_key, &src->auth_key); } /* Calculate HMAC-SHA1 key for long term credential, by getting * MD5 digest of username, realm, and password. */ static void calc_md5_key(pj_uint8_t digest[16], const pj_str_t *realm, const pj_str_t *username, const pj_str_t *passwd) { /* The 16-byte key for MESSAGE-INTEGRITY HMAC is formed by taking * the MD5 hash of the result of concatenating the following five * fields: (1) The username, with any quotes and trailing nulls * removed, (2) A single colon, (3) The realm, with any quotes and * trailing nulls removed, (4) A single colon, and (5) The * password, with any trailing nulls removed. */ pj_md5_context ctx; pj_str_t s; pj_md5_init(&ctx); #define REMOVE_QUOTE(s) if (s.slen && *s.ptr=='"') \ s.ptr++, s.slen--; \ if (s.slen && s.ptr[s.slen-1]=='"') \ s.slen--; /* Add username */ s = *username; REMOVE_QUOTE(s); pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, (unsigned)s.slen); /* Add single colon */ pj_md5_update(&ctx, (pj_uint8_t*)":", 1); /* Add realm */ s = *realm; REMOVE_QUOTE(s); pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, (unsigned)s.slen); #undef REMOVE_QUOTE /* Another colon */ pj_md5_update(&ctx, (pj_uint8_t*)":", 1); /* Add password */ pj_md5_update(&ctx, (pj_uint8_t*)passwd->ptr, (unsigned)passwd->slen); /* Done */ pj_md5_final(&ctx, digest); } /* * Create authentication key to be used for encoding the message with * MESSAGE-INTEGRITY. */ PJ_DEF(void) pj_stun_create_key(pj_pool_t *pool, pj_str_t *key, const pj_str_t *realm, const pj_str_t *username, pj_stun_passwd_type data_type, const pj_str_t *data) { PJ_ASSERT_ON_FAIL(pool && key && username && data, return); if (realm && realm->slen) { if (data_type == PJ_STUN_PASSWD_PLAIN) { key->ptr = (char*) pj_pool_alloc(pool, 16); calc_md5_key((pj_uint8_t*)key->ptr, realm, username, data); key->slen = 16; } else { pj_strdup(pool, key, data); } } else { pj_assert(data_type == PJ_STUN_PASSWD_PLAIN); pj_strdup(pool, key, data); } } /*unused PJ_INLINE(pj_uint16_t) GET_VAL16(const pj_uint8_t *pdu, unsigned pos) { return (pj_uint16_t) ((pdu[pos] << 8) + pdu[pos+1]); }*/ PJ_INLINE(void) PUT_VAL16(pj_uint8_t *buf, unsigned pos, pj_uint16_t hval) { buf[pos+0] = (pj_uint8_t) ((hval & 0xFF00) >> 8); buf[pos+1] = (pj_uint8_t) ((hval & 0x00FF) >> 0); } /* Send 401 response */ static pj_status_t create_challenge(pj_pool_t *pool, const pj_stun_msg *msg, int err_code, const char *errstr, const pj_str_t *realm, const pj_str_t *nonce, pj_stun_msg **p_response) { pj_stun_msg *response; pj_str_t tmp_nonce; pj_str_t err_msg; pj_status_t rc; rc = pj_stun_msg_create_response(pool, msg, err_code, (errstr?pj_cstr(&err_msg, errstr):NULL), &response); if (rc != PJ_SUCCESS) return rc; /* SHOULD NOT add REALM, NONCE, USERNAME, and M-I on 400 response */ if (err_code!=400 && realm && realm->slen) { rc = pj_stun_msg_add_string_attr(pool, response, PJ_STUN_ATTR_REALM, realm); if (rc != PJ_SUCCESS) return rc; /* long term must include nonce */ if (!nonce || nonce->slen == 0) { tmp_nonce = pj_str("pjstun"); nonce = &tmp_nonce; } } if (err_code!=400 && nonce && nonce->slen) { rc = pj_stun_msg_add_string_attr(pool, response, PJ_STUN_ATTR_NONCE, nonce); if (rc != PJ_SUCCESS) return rc; } *p_response = response; return PJ_SUCCESS; } /* Verify credential in the request */ PJ_DEF(pj_status_t) pj_stun_authenticate_request(const pj_uint8_t *pkt, unsigned pkt_len, const pj_stun_msg *msg, pj_stun_auth_cred *cred, pj_pool_t *pool, pj_stun_req_cred_info *p_info, pj_stun_msg **p_response) { pj_stun_req_cred_info tmp_info; const pj_stun_msgint_attr *amsgi; unsigned i, amsgi_pos; pj_bool_t has_attr_beyond_mi; const pj_stun_username_attr *auser; const pj_stun_realm_attr *arealm; const pj_stun_realm_attr *anonce; pj_hmac_sha1_context ctx; pj_uint8_t digest[PJ_SHA1_DIGEST_SIZE]; pj_stun_status err_code; const char *err_text = NULL; pj_status_t status; /* msg and credential MUST be specified */ PJ_ASSERT_RETURN(pkt && pkt_len && msg && cred, PJ_EINVAL); /* If p_response is specified, pool MUST be specified. */ PJ_ASSERT_RETURN(!p_response || pool, PJ_EINVAL); if (p_response) *p_response = NULL; if (!PJ_STUN_IS_REQUEST(msg->hdr.type)) p_response = NULL; if (p_info == NULL) p_info = &tmp_info; pj_bzero(p_info, sizeof(pj_stun_req_cred_info)); /* Get realm and nonce from credential */ p_info->realm.slen = p_info->nonce.slen = 0; if (cred->type == PJ_STUN_AUTH_CRED_STATIC) { p_info->realm = cred->data.static_cred.realm; p_info->nonce = cred->data.static_cred.nonce; } else if (cred->type == PJ_STUN_AUTH_CRED_DYNAMIC) { status = cred->data.dyn_cred.get_auth(cred->data.dyn_cred.user_data, pool, &p_info->realm, &p_info->nonce); if (status != PJ_SUCCESS) return status; } else { pj_assert(!"Invalid credential type"); return PJ_EBUG; } /* Look for MESSAGE-INTEGRITY while counting the position */ amsgi_pos = 0; has_attr_beyond_mi = PJ_FALSE; amsgi = NULL; for (i=0; iattr_count; ++i) { if (msg->attr[i]->type == PJ_STUN_ATTR_MESSAGE_INTEGRITY) { amsgi = (const pj_stun_msgint_attr*) msg->attr[i]; } else if (amsgi) { has_attr_beyond_mi = PJ_TRUE; break; } else { amsgi_pos += ((msg->attr[i]->length+3) & ~0x03) + 4; } } if (amsgi == NULL) { /* According to rfc3489bis-10 Sec 10.1.2/10.2.2, we should return 400 for short term, and 401 for long term. The rule has been changed from rfc3489bis-06 */ err_code = p_info->realm.slen ? PJ_STUN_SC_UNAUTHORIZED : PJ_STUN_SC_BAD_REQUEST; goto on_auth_failed; } /* Next check that USERNAME is present */ auser = (const pj_stun_username_attr*) pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_USERNAME, 0); if (auser == NULL) { /* According to rfc3489bis-10 Sec 10.1.2/10.2.2, we should return 400 for both short and long term, since M-I is present. The rule has been changed from rfc3489bis-06 */ err_code = PJ_STUN_SC_BAD_REQUEST; err_text = "Missing USERNAME"; goto on_auth_failed; } /* Get REALM, if any */ arealm = (const pj_stun_realm_attr*) pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_REALM, 0); /* Reject with 400 if we have long term credential and the request * is missing REALM attribute. */ if (p_info->realm.slen && arealm==NULL) { err_code = PJ_STUN_SC_BAD_REQUEST; err_text = "Missing REALM"; goto on_auth_failed; } /* Check if username match */ if (cred->type == PJ_STUN_AUTH_CRED_STATIC) { pj_bool_t username_ok; username_ok = !pj_strcmp(&auser->value, &cred->data.static_cred.username); if (username_ok) { pj_strdup(pool, &p_info->username, &cred->data.static_cred.username); pj_stun_create_key(pool, &p_info->auth_key, &p_info->realm, &auser->value, cred->data.static_cred.data_type, &cred->data.static_cred.data); } else { /* Username mismatch */ /* According to rfc3489bis-10 Sec 10.1.2/10.2.2, we should * return 401 */ err_code = PJ_STUN_SC_UNAUTHORIZED; goto on_auth_failed; } } else if (cred->type == PJ_STUN_AUTH_CRED_DYNAMIC) { pj_stun_passwd_type data_type = PJ_STUN_PASSWD_PLAIN; pj_str_t password; pj_status_t rc; rc = cred->data.dyn_cred.get_password(msg, cred->data.dyn_cred.user_data, (arealm?&arealm->value:NULL), &auser->value, pool, &data_type, &password); if (rc == PJ_SUCCESS) { pj_strdup(pool, &p_info->username, &auser->value); pj_stun_create_key(pool, &p_info->auth_key, (arealm?&arealm->value:NULL), &auser->value, data_type, &password); } else { err_code = PJ_STUN_SC_UNAUTHORIZED; goto on_auth_failed; } } else { pj_assert(!"Invalid credential type"); return PJ_EBUG; } /* Get NONCE attribute */ anonce = (pj_stun_nonce_attr*) pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_NONCE, 0); /* Check for long term/short term requirements. */ if (p_info->realm.slen != 0 && arealm == NULL) { /* Long term credential is required and REALM is not present */ err_code = PJ_STUN_SC_BAD_REQUEST; err_text = "Missing REALM"; goto on_auth_failed; } else if (p_info->realm.slen != 0 && arealm != NULL) { /* We want long term, and REALM is present */ /* NONCE must be present. */ if (anonce == NULL && p_info->nonce.slen) { err_code = PJ_STUN_SC_BAD_REQUEST; err_text = "Missing NONCE"; goto on_auth_failed; } /* Verify REALM matches */ if (pj_stricmp(&arealm->value, &p_info->realm)) { /* REALM doesn't match */ err_code = PJ_STUN_SC_UNAUTHORIZED; err_text = "Invalid REALM"; goto on_auth_failed; } /* Valid case, will validate the message integrity later */ } else if (p_info->realm.slen == 0 && arealm != NULL) { /* We want to use short term credential, but client uses long * term credential. The draft doesn't mention anything about * switching between long term and short term. */ /* For now just accept the credential, anyway it will probably * cause wrong message integrity value later. */ } else if (p_info->realm.slen==0 && arealm == NULL) { /* Short term authentication is wanted, and one is supplied */ /* Application MAY request NONCE to be supplied */ if (p_info->nonce.slen != 0) { err_code = PJ_STUN_SC_UNAUTHORIZED; err_text = "NONCE required"; goto on_auth_failed; } } /* If NONCE is present, validate it */ if (anonce) { pj_bool_t ok; if (cred->type == PJ_STUN_AUTH_CRED_DYNAMIC && cred->data.dyn_cred.verify_nonce != NULL) { ok=cred->data.dyn_cred.verify_nonce(msg, cred->data.dyn_cred.user_data, (arealm?&arealm->value:NULL), &auser->value, &anonce->value); } else if (cred->type == PJ_STUN_AUTH_CRED_DYNAMIC) { ok = PJ_TRUE; } else { if (p_info->nonce.slen) { ok = !pj_strcmp(&anonce->value, &p_info->nonce); } else { ok = PJ_TRUE; } } if (!ok) { err_code = PJ_STUN_SC_STALE_NONCE; goto on_auth_failed; } } /* Now calculate HMAC of the message. */ pj_hmac_sha1_init(&ctx, (pj_uint8_t*)p_info->auth_key.ptr, (unsigned)p_info->auth_key.slen); #if PJ_STUN_OLD_STYLE_MI_FINGERPRINT /* Pre rfc3489bis-06 style of calculation */ pj_hmac_sha1_update(&ctx, pkt, 20); #else /* First calculate HMAC for the header. * The calculation is different depending on whether FINGERPRINT attribute * is present in the message. */ if (has_attr_beyond_mi) { pj_uint8_t hdr_copy[20]; pj_memcpy(hdr_copy, pkt, 20); PUT_VAL16(hdr_copy, 2, (pj_uint16_t)(amsgi_pos + 24)); pj_hmac_sha1_update(&ctx, hdr_copy, 20); } else { pj_hmac_sha1_update(&ctx, pkt, 20); } #endif /* PJ_STUN_OLD_STYLE_MI_FINGERPRINT */ /* Now update with the message body */ pj_hmac_sha1_update(&ctx, pkt+20, amsgi_pos); #if PJ_STUN_OLD_STYLE_MI_FINGERPRINT // This is no longer necessary as per rfc3489bis-08 if ((amsgi_pos+20) & 0x3F) { pj_uint8_t zeroes[64]; pj_bzero(zeroes, sizeof(zeroes)); pj_hmac_sha1_update(&ctx, zeroes, 64-((amsgi_pos+20) & 0x3F)); } #endif pj_hmac_sha1_final(&ctx, digest); /* Compare HMACs */ if (pj_memcmp(amsgi->hmac, digest, 20)) { /* HMAC value mismatch */ /* According to rfc3489bis-10 Sec 10.1.2 we should return 401 */ err_code = PJ_STUN_SC_UNAUTHORIZED; err_text = "MESSAGE-INTEGRITY mismatch"; goto on_auth_failed; } /* Everything looks okay! */ return PJ_SUCCESS; on_auth_failed: if (p_response) { create_challenge(pool, msg, err_code, err_text, &p_info->realm, &p_info->nonce, p_response); } return PJ_STATUS_FROM_STUN_CODE(err_code); } /* Determine if STUN message can be authenticated */ PJ_DEF(pj_bool_t) pj_stun_auth_valid_for_msg(const pj_stun_msg *msg) { unsigned msg_type = msg->hdr.type; const pj_stun_errcode_attr *err_attr; /* STUN requests and success response can be authenticated */ if (!PJ_STUN_IS_ERROR_RESPONSE(msg_type) && !PJ_STUN_IS_INDICATION(msg_type)) { return PJ_TRUE; } /* STUN Indication cannot be authenticated */ if (PJ_STUN_IS_INDICATION(msg_type)) return PJ_FALSE; /* Authentication for STUN error responses depend on the error * code. */ err_attr = (const pj_stun_errcode_attr*) pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_ERROR_CODE, 0); if (err_attr == NULL) { PJ_LOG(4,(THIS_FILE, "STUN error code attribute not present in " "error response")); return PJ_TRUE; } switch (err_attr->err_code) { case PJ_STUN_SC_BAD_REQUEST: /* 400 (Bad Request) */ case PJ_STUN_SC_UNAUTHORIZED: /* 401 (Unauthorized) */ case PJ_STUN_SC_STALE_NONCE: /* 438 (Stale Nonce) */ /* Due to the way this response is generated here, we can't really * authenticate 420 (Unknown Attribute) response */ case PJ_STUN_SC_UNKNOWN_ATTRIBUTE: return PJ_FALSE; default: return PJ_TRUE; } } /* Authenticate MESSAGE-INTEGRITY in the response */ PJ_DEF(pj_status_t) pj_stun_authenticate_response(const pj_uint8_t *pkt, unsigned pkt_len, const pj_stun_msg *msg, const pj_str_t *key) { const pj_stun_msgint_attr *amsgi; unsigned i, amsgi_pos; pj_bool_t has_attr_beyond_mi; pj_hmac_sha1_context ctx; pj_uint8_t digest[PJ_SHA1_DIGEST_SIZE]; PJ_ASSERT_RETURN(pkt && pkt_len && msg && key, PJ_EINVAL); /* First check that MESSAGE-INTEGRITY is present */ amsgi = (const pj_stun_msgint_attr*) pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_MESSAGE_INTEGRITY, 0); if (amsgi == NULL) { return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNAUTHORIZED); } /* Check that message length is valid */ if (msg->hdr.length < 24) { return PJNATH_EINSTUNMSGLEN; } /* Look for MESSAGE-INTEGRITY while counting the position */ amsgi_pos = 0; has_attr_beyond_mi = PJ_FALSE; amsgi = NULL; for (i=0; iattr_count; ++i) { if (msg->attr[i]->type == PJ_STUN_ATTR_MESSAGE_INTEGRITY) { amsgi = (const pj_stun_msgint_attr*) msg->attr[i]; } else if (amsgi) { has_attr_beyond_mi = PJ_TRUE; break; } else { amsgi_pos += ((msg->attr[i]->length+3) & ~0x03) + 4; } } if (amsgi == NULL) { return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_BAD_REQUEST); } /* Now calculate HMAC of the message. */ pj_hmac_sha1_init(&ctx, (pj_uint8_t*)key->ptr, (unsigned)key->slen); #if PJ_STUN_OLD_STYLE_MI_FINGERPRINT /* Pre rfc3489bis-06 style of calculation */ pj_hmac_sha1_update(&ctx, pkt, 20); #else /* First calculate HMAC for the header. * The calculation is different depending on whether FINGERPRINT attribute * is present in the message. */ if (has_attr_beyond_mi) { pj_uint8_t hdr_copy[20]; pj_memcpy(hdr_copy, pkt, 20); PUT_VAL16(hdr_copy, 2, (pj_uint16_t)(amsgi_pos+24)); pj_hmac_sha1_update(&ctx, hdr_copy, 20); } else { pj_hmac_sha1_update(&ctx, pkt, 20); } #endif /* PJ_STUN_OLD_STYLE_MI_FINGERPRINT */ /* Now update with the message body */ pj_hmac_sha1_update(&ctx, pkt+20, amsgi_pos); #if PJ_STUN_OLD_STYLE_MI_FINGERPRINT // This is no longer necessary as per rfc3489bis-08 if ((amsgi_pos+20) & 0x3F) { pj_uint8_t zeroes[64]; pj_bzero(zeroes, sizeof(zeroes)); pj_hmac_sha1_update(&ctx, zeroes, 64-((amsgi_pos+20) & 0x3F)); } #endif pj_hmac_sha1_final(&ctx, digest); /* Compare HMACs */ if (pj_memcmp(amsgi->hmac, digest, 20)) { /* HMAC value mismatch */ return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_UNAUTHORIZED); } /* Everything looks okay! */ return PJ_SUCCESS; }