| 1 | /* |
| 2 | COPYRIGHT AND PERMISSION NOTICE |
| 3 | |
| 4 | Copyright (c) 1996 - 2010, Daniel Stenberg, <daniel@haxx.se>. |
| 5 | |
| 6 | All rights reserved. |
| 7 | |
| 8 | Permission to use, copy, modify, and distribute this software for any purpose |
| 9 | with or without fee is hereby granted, provided that the above copyright |
| 10 | notice and this permission notice appear in all copies. |
| 11 | |
| 12 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 13 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 14 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN |
| 15 | NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, |
| 16 | DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
| 17 | OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE |
| 18 | OR OTHER DEALINGS IN THE SOFTWARE. |
| 19 | |
| 20 | Except as contained in this notice, the name of a copyright holder shall not |
| 21 | be used in advertising or otherwise to promote the sale, use or other dealings |
| 22 | in this Software without prior written authorization of the copyright holder. |
| 23 | */ |
| 24 | /* simplified to a basic host name check */ |
| 25 | #include <openssl/x509_vfy.h> |
| 26 | #include <openssl/x509v3.h> |
| 27 | #include <string.h> |
| 28 | |
| 29 | #define bool int |
| 30 | #define false 0 |
| 31 | #define true 1 |
| 32 | /** @fn static bool cert_hostcheck(const char *hostname, char *pattern) |
| 33 | * Verifies that the hostname matches against the pattern specified. |
| 34 | * Handles wildcard patterns and ignores the distinction between upper and lower |
| 35 | * case letters. Note: Ported over from ssluse.c in curl (7.1.16) lib Note: |
| 36 | * Explicit pattern match disabled as we do not use that for processing node |
| 37 | * certificate. Note: No longer ignores the distinction between upper and lower |
| 38 | * case letters. Our certificate is generated with lowercase letters. |
| 39 | * @return true if matches, false otherwise |
| 40 | * @param hostname The hostname we want to check. e.g: vault.trustcommerce.com |
| 41 | * @param pattern The pattern we wish to match against. e.g: *.trustcommerce.com |
| 42 | */ |
| 43 | bool |
| 44 | cert_hostcheck(const char* pattern, const char* hostname) |
| 45 | { |
| 46 | if (!hostname || !pattern || !*hostname || !*pattern) |
| 47 | return false; |
| 48 | if (!strcmp(hostname, pattern)) |
| 49 | return true; |
| 50 | return false; |
| 51 | } |
| 52 | /** @fn static bool checkCertificate(X509 *cert, char *host) |
| 53 | * Provides validation of the hostname associated with a certificate. |
| 54 | * See RFC2818 - Server Identity for an overview of the concept. |
| 55 | * This implementation is based off the one found in curl-7.16.1: ssluse.c |
| 56 | * but we treat the subjectAltName as a recommendation... so if it fails, |
| 57 | * we will proceed to the CN check. |
| 58 | * The rationale for this is that we are not always using HTTP (over SSL) |
| 59 | * and its more of a certification generation / CA issue and we want |
| 60 | * maximum interoperability (as opposed to strict compliance). |
| 61 | * @param cert The X509 certificate in question. |
| 62 | * @param host The hostname or ip we wish to check. |
| 63 | * @return true if matches, false otherwise |
| 64 | */ |
| 65 | static bool |
| 66 | checkCertificate(X509* cert, const char* host) |
| 67 | { |
| 68 | int i, j; |
| 69 | bool matched = false; |
| 70 | STACK_OF(GENERAL_NAME) * altnames; |
| 71 | unsigned char nulstr[] = { '\0' }; |
| 72 | unsigned char* peer_CN = nulstr; |
| 73 | X509_NAME* name; |
| 74 | ASN1_STRING* tmp; |
| 75 | bool status = false; |
| 76 | |
| 77 | if (!cert || !host) |
| 78 | return false; |
| 79 | |
| 80 | altnames = (STACK_OF(GENERAL_NAME)*)(X509_get_ext_d2i( |
| 81 | cert, NID_subject_alt_name, NULL, NULL)); |
| 82 | |
| 83 | if (altnames != NULL) { |
| 84 | int numalts = sk_GENERAL_NAME_num(altnames); |
| 85 | for (i = 0; (i < numalts) && (matched == false); i++) { |
| 86 | const GENERAL_NAME* check = sk_GENERAL_NAME_value(altnames, i); |
| 87 | #if OPENSSL_VERSION_NUMBER < 0x10100000L |
| 88 | const char* altptr = (char*)(ASN1_STRING_data(check->d.ia5)); |
| 89 | #else |
| 90 | const char* altptr = (char*)(ASN1_STRING_get0_data(check->d.ia5)); |
| 91 | #endif |
| 92 | size_t altlen; |
| 93 | switch (check->type) { |
| 94 | case GEN_DNS: |
| 95 | altlen = ASN1_STRING_length(check->d.ia5); |
| 96 | if (altlen == strlen(host) && cert_hostcheck(altptr, host)) |
| 97 | matched = true; |
| 98 | break; |
| 99 | case GEN_IPADD: |
| 100 | altlen = ASN1_STRING_length(check->d.ia5); |
| 101 | if (altlen == strlen(host) && !memcmp(altptr, host, altlen)) |
| 102 | matched = true; |
| 103 | break; |
| 104 | } |
| 105 | } |
| 106 | GENERAL_NAMES_free(altnames); |
| 107 | if (matched != false) |
| 108 | return true; |
| 109 | } |
| 110 | |
| 111 | i = j = -1; |
| 112 | |
| 113 | name = X509_get_subject_name(cert); |
| 114 | if (!name) |
| 115 | return false; |
| 116 | |
| 117 | // get the last CN found in the subject (supposedly its the most distinguished |
| 118 | // one) |
| 119 | while ((j = X509_NAME_get_index_by_NID(name, NID_commonName, i)) >= 0) |
| 120 | i = j; |
| 121 | |
| 122 | if (i < 0) |
| 123 | return false; |
| 124 | |
| 125 | tmp = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, i)); |
| 126 | /* workaround for version of openssl < 0.9.7d */ |
| 127 | if (tmp && ASN1_STRING_type(tmp) == V_ASN1_UTF8STRING) { |
| 128 | j = ASN1_STRING_length(tmp); |
| 129 | if (j >= 0) { |
| 130 | peer_CN = (unsigned char*)(OPENSSL_malloc(j + 1)); |
| 131 | if (peer_CN) { |
| 132 | #if OPENSSL_VERSION_NUMBER < 0x10100000L |
| 133 | memcpy(peer_CN, ASN1_STRING_data(tmp), j); |
| 134 | #else |
| 135 | memcpy(peer_CN, ASN1_STRING_get0_data(tmp), j); |
| 136 | #endif |
| 137 | peer_CN[j] = '\0'; |
| 138 | } |
| 139 | } |
| 140 | } else { |
| 141 | j = ASN1_STRING_to_UTF8(&peer_CN, tmp); |
| 142 | } |
| 143 | |
| 144 | if (peer_CN == nulstr) |
| 145 | peer_CN = NULL; |
| 146 | |
| 147 | if (peer_CN == NULL) |
| 148 | return false; // the cn isnt missing in virtually all cases |
| 149 | else if (!cert_hostcheck((char*)(peer_CN), host)) |
| 150 | status = false; |
| 151 | else |
| 152 | status = true; |
| 153 | |
| 154 | if (peer_CN) |
| 155 | OPENSSL_free(peer_CN); |
| 156 | return status; |
| 157 | } |
| 158 | |
| 159 | int |
| 160 | TCLinkDefaultValidate(int x, void* cert) |
| 161 | { |
| 162 | if (x != 0 || cert == NULL) |
| 163 | return 0; |
| 164 | return !checkCertificate((X509*)cert, "pgw1.trustcommerce.com"); |
| 165 | } |