1 | #include <assert.h> |
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2 | |
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3 | #include <library.h> |
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4 | #include <credentials/certificates/certificate.h> |
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5 | #include <credentials/certificates/x509.h> |
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6 | #include <credentials/certificates/ac.h> |
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7 | |
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8 | #include "abac_verifier.h" |
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9 | |
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10 | #include "abac_util.h" |
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11 | |
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12 | typedef struct _abac_id_cert_t { |
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13 | char *keyid; |
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14 | certificate_t *cert; |
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15 | |
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16 | UT_hash_handle hh; |
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17 | } abac_id_cert_t; |
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18 | |
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19 | struct _abac_credential_t { |
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20 | abac_role_t *head; |
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21 | abac_role_t *tail; |
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22 | certificate_t *cert; |
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23 | certificate_t *issuer; |
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24 | }; |
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25 | |
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26 | abac_id_cert_t *id_certs = NULL; |
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27 | |
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28 | // convert a chunk to a lowercase binary string |
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29 | // malloc's the string |
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30 | static char *_chunk_to_string(chunk_t chunk) { |
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31 | int i; |
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32 | |
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33 | char *ret = abac_xmalloc(chunk.len * 2 + 1); |
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34 | |
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35 | for (i = 0; i < chunk.len; ++i) |
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36 | sprintf(ret + 2 * i, "%02x", chunk.ptr[i]); |
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37 | |
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38 | return ret; |
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39 | } |
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40 | |
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41 | // verify that cert was issued by issuer |
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42 | // cert and issuer can be the same, in which case the self-sig is validated |
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43 | static int _verify_cert(certificate_t *issuer, certificate_t *cert) { |
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44 | // XXX make sure this checks signature |
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45 | if (cert->issued_by(cert, issuer)) |
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46 | if (cert->get_validity(cert, NULL, NULL, NULL)) |
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47 | return 1; |
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48 | return 0; |
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49 | } |
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50 | |
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51 | /** |
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52 | * Init the verifier subsystem. |
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53 | */ |
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54 | void abac_verifier_init(void) { |
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55 | atexit(library_deinit); |
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56 | |
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57 | if (!library_init(NULL)) |
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58 | exit(SS_RC_LIBSTRONGSWAN_INTEGRITY); |
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59 | |
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60 | if (!lib->plugins->load(lib->plugins, NULL, |
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61 | lib->settings->get_str(lib->settings, "pki.load", PLUGINS))) |
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62 | exit(SS_RC_INITIALIZATION_FAILED); |
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63 | } |
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64 | |
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65 | /** |
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66 | * Uninitialize the system, free up any allocated memory. |
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67 | */ |
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68 | void abac_verifier_deinit(void) { |
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69 | abac_id_cert_t *id; |
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70 | |
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71 | while ((id = id_certs) != NULL) { |
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72 | HASH_DEL(id_certs, id); |
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73 | |
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74 | free(id->keyid); |
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75 | id->cert->destroy(id->cert); |
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76 | free(id); |
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77 | } |
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78 | } |
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79 | |
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80 | /** |
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81 | * Load an ID certificate. |
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82 | */ |
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83 | static int _load_id(certificate_t *cert) { |
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84 | public_key_t *public = NULL; |
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85 | char *keyid = NULL; |
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86 | chunk_t id; |
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87 | int ret; |
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88 | |
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89 | assert(cert != NULL); |
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90 | |
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91 | // get the cert's pub key |
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92 | public = cert->get_public_key(cert); |
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93 | if (public == NULL) goto error; |
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94 | |
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95 | // get the pubkey's fingerprint |
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96 | ret = public->get_fingerprint( |
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97 | public, |
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98 | KEY_ID_PUBKEY_INFO_SHA1, &id |
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99 | ); |
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100 | if (!ret) goto error; |
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101 | |
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102 | // validate sig |
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103 | ret = _verify_cert(cert, cert); |
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104 | if (!ret) goto error; |
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105 | |
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106 | keyid = _chunk_to_string(id); |
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107 | |
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108 | // success, add the key to the map of certificates |
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109 | abac_id_cert_t *id_cert = abac_xmalloc(sizeof(abac_id_cert_t)); |
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110 | id_cert->keyid = keyid; |
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111 | id_cert->cert = cert; |
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112 | HASH_ADD_KEYPTR(hh, id_certs, id_cert->keyid, strlen(id_cert->keyid), id_cert); |
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113 | |
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114 | public->destroy(public); |
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115 | |
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116 | return 1; |
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117 | |
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118 | error: |
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119 | if (public != NULL) public->destroy(public); |
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120 | |
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121 | return 0; |
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122 | } |
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123 | |
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124 | /** |
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125 | * Load an ID cert from a file. |
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126 | */ |
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127 | int abac_verifier_load_id_file(char *filename) { |
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128 | // load the cert |
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129 | certificate_t *cert = lib->creds->create( |
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130 | lib->creds, CRED_CERTIFICATE, CERT_X509, |
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131 | BUILD_FROM_FILE, filename, |
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132 | BUILD_X509_FLAG, X509_AA, // attribute authority, dumb |
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133 | BUILD_END |
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134 | ); |
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135 | if (cert == NULL) |
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136 | return 0; |
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137 | return _load_id(cert); |
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138 | } |
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139 | |
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140 | /** |
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141 | * Load an ID cert from a chunk. |
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142 | */ |
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143 | int abac_verifier_load_id_chunk(chunk_t chunk) { |
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144 | // load the cert |
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145 | certificate_t *cert = lib->creds->create( |
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146 | lib->creds, CRED_CERTIFICATE, CERT_X509, |
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147 | BUILD_BLOB_ASN1_DER, chunk, |
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148 | BUILD_X509_FLAG, X509_AA, // attribute authority, dumb |
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149 | BUILD_END |
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150 | ); |
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151 | if (cert == NULL) |
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152 | return 0; |
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153 | return _load_id(cert); |
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154 | } |
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155 | |
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156 | /** |
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157 | * Load an attribute cert. |
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158 | * Returns true only if the certificate is valid and is issued by the proper |
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159 | * authority. |
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160 | */ |
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161 | static abac_credential_t *_load_attribute_cert(certificate_t *cert) { |
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162 | ietf_attributes_t *attr_cert = NULL; |
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163 | abac_role_t *head_role = NULL; |
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164 | abac_role_t *tail_role = NULL; |
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165 | abac_id_cert_t *issuer; |
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166 | int ret; |
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167 | |
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168 | // get the attr |
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169 | ac_t *ac = (ac_t *)cert; |
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170 | attr_cert = ac->get_groups(ac); |
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171 | if (attr_cert == NULL) goto error; |
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172 | |
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173 | char *attr_string = attr_cert->get_string(attr_cert); |
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174 | if (attr_string == NULL) goto error; |
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175 | |
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176 | // split into head/tail parts |
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177 | char head[256], tail[256]; |
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178 | ret = sscanf(attr_string, "%255s <- %255s", head, tail); |
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179 | if (ret != 2) goto error; |
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180 | |
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181 | // must be a role |
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182 | head_role = abac_role_from_string(head); |
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183 | if (head_role == NULL) goto error; |
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184 | if (!abac_role_is_role(head_role)) goto error; |
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185 | |
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186 | // make sure the tail role is valid |
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187 | tail_role = abac_role_from_string(tail); |
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188 | if (tail_role == NULL) goto error; |
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189 | |
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190 | // get the issuer based on keyid |
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191 | char *principal = abac_role_principal(head_role); |
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192 | HASH_FIND_STR(id_certs, principal, issuer); |
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193 | if (issuer == NULL) goto error; |
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194 | |
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195 | // make sure the issuer's signed it |
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196 | ret = _verify_cert(issuer->cert, cert); |
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197 | if (!ret) goto error; |
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198 | |
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199 | // at this point we know we have a good attribute cert |
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200 | abac_credential_t *cred = abac_xmalloc(sizeof(abac_credential_t)); |
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201 | cred->head = head_role; |
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202 | cred->tail = tail_role; |
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203 | cred->cert = cert; |
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204 | cred->issuer = issuer->cert->get_ref(issuer->cert); |
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205 | |
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206 | // free up some crap |
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207 | attr_cert->destroy(attr_cert); |
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208 | |
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209 | return cred; |
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210 | |
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211 | error: |
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212 | if (cert != NULL) cert->destroy(cert); |
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213 | if (attr_cert != NULL) attr_cert->destroy(attr_cert); |
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214 | if (head_role != NULL) abac_role_free(head_role); |
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215 | if (tail_role != NULL) abac_role_free(tail_role); |
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216 | |
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217 | return NULL; |
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218 | } |
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219 | |
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220 | /** |
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221 | * Load an attribute cert from a file. |
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222 | */ |
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223 | abac_credential_t *abac_verifier_load_attribute_cert_file(char *filename) { |
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224 | // load the cert |
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225 | certificate_t *cert = lib->creds->create( |
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226 | lib->creds, CRED_CERTIFICATE, CERT_X509_AC, |
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227 | BUILD_FROM_FILE, filename, |
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228 | BUILD_END |
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229 | ); |
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230 | if (cert == NULL) |
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231 | return NULL; |
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232 | return _load_attribute_cert(cert); |
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233 | } |
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234 | |
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235 | /** |
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236 | * Load an attribute cert from a chunk. |
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237 | */ |
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238 | abac_credential_t *abac_verifier_load_attribute_cert_chunk(chunk_t chunk) { |
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239 | // load the cert |
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240 | certificate_t *cert = lib->creds->create( |
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241 | lib->creds, CRED_CERTIFICATE, CERT_X509_AC, |
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242 | BUILD_BLOB_ASN1_DER, chunk, |
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243 | BUILD_END |
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244 | ); |
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245 | if (cert == NULL) |
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246 | return NULL; |
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247 | return _load_attribute_cert(cert); |
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248 | } |
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249 | |
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250 | /** |
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251 | * Return the head role. |
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252 | */ |
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253 | abac_role_t *abac_credential_head(abac_credential_t *cred) { |
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254 | return cred->head; |
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255 | } |
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256 | |
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257 | /** |
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258 | * Return the tail role. |
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259 | */ |
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260 | abac_role_t *abac_credential_tail(abac_credential_t *cred) { |
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261 | return cred->tail; |
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262 | } |
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263 | |
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264 | /** |
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265 | * Return the encoding of the attribute cert. |
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266 | */ |
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267 | abac_chunk_t abac_credential_attribute_cert(abac_credential_t *cred) { |
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268 | chunk_t encoding = cred->cert->get_encoding(cred->cert); |
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269 | abac_chunk_t ret = { encoding.ptr, encoding.len }; |
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270 | return ret; |
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271 | } |
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272 | |
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273 | /** |
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274 | * Return the encoding of the issuer cert. |
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275 | */ |
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276 | abac_chunk_t abac_credential_issuer_cert(abac_credential_t *cred) { |
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277 | chunk_t encoding = cred->issuer->get_encoding(cred->issuer); |
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278 | abac_chunk_t ret = { encoding.ptr, encoding.len }; |
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279 | return ret; |
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280 | } |
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281 | |
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282 | /** |
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283 | * Copy a credential. |
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284 | */ |
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285 | abac_credential_t *abac_credential_dup(abac_credential_t *cred) { |
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286 | assert(cred != NULL); |
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287 | |
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288 | abac_credential_t *clone = abac_xmalloc(sizeof(abac_credential_t)); |
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289 | |
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290 | clone->head = abac_role_dup(cred->head); |
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291 | clone->tail = abac_role_dup(cred->tail); |
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292 | clone->cert = cred->cert->get_ref(cred->cert); |
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293 | clone->issuer = cred->issuer->get_ref(cred->issuer); |
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294 | |
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295 | return clone; |
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296 | } |
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297 | |
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298 | /** |
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299 | * Free a credential. |
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300 | */ |
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301 | void abac_credential_free(abac_credential_t *cred) { |
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302 | if (cred == NULL) |
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303 | return; |
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304 | |
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305 | abac_role_free(cred->head); |
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306 | abac_role_free(cred->tail); |
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307 | cred->cert->destroy(cred->cert); |
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308 | cred->issuer->destroy(cred->issuer); // reference counted |
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309 | |
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310 | free(cred); |
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311 | } |
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