1 | |
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2 | /* abac_verifier.c */ |
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3 | #include <assert.h> |
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4 | |
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5 | #include "libabac_common.h" |
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6 | #include "abac.h" |
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7 | |
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8 | #include "abac_list.h" |
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9 | #include "uthash.h" |
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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; // using cert's keyid |
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14 | abac_id_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 | abac_id_t *issuer; /* Acme of Acme.customer <- Coyote */ |
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23 | abac_attribute_t *cert; |
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24 | |
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25 | int refcount; |
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26 | }; |
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27 | |
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28 | /* hash table of all the principal id credentials */ |
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29 | abac_id_cert_t *id_certs = NULL; |
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30 | |
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31 | /***********************************************************************/ |
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32 | // convert a chunk to a lowercase binary string |
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33 | // malloc's the string |
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34 | /*** not used, |
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35 | static char *_chunk_to_string(abac_chunk_t chunk) { |
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36 | int i; |
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37 | |
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38 | char *ret = abac_xmalloc(chunk.len * 2 + 1); |
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39 | |
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40 | for (i = 0; i < chunk.len; ++i) |
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41 | sprintf(ret + 2 * i, "%02x", chunk.ptr[i]); |
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42 | |
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43 | return ret; |
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44 | } |
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45 | ***/ |
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46 | |
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47 | // verify that cert was issued by issuer |
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48 | // cert and issuer can be the same, in which case the self-sig is validated |
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49 | /*** not used |
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50 | static int _verify_cert(abac_id_t *cert) { |
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51 | |
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52 | assert(cert); |
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53 | if(!abac_id_still_valid(cert)) |
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54 | return 0; |
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55 | return 1; |
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56 | } |
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57 | ***/ |
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58 | |
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59 | /** |
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60 | * Init the verifier subsystem. |
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61 | */ |
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62 | void abac_verifier_init(void) { |
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63 | init_openssl(); |
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64 | init_xmlsec(); |
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65 | } |
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66 | |
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67 | /** |
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68 | * Uninitialize the system, free up any allocated memory. |
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69 | */ |
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70 | void abac_verifier_deinit(void) { |
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71 | abac_id_cert_t *id; |
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72 | |
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73 | while ((id = id_certs) != NULL) { |
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74 | HASH_DEL(id_certs, id); |
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75 | |
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76 | free(id->keyid); |
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77 | abac_id_free(id->cert); |
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78 | free(id); |
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79 | } |
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80 | deinit_xmlsec(); |
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81 | deinit_openssl(); |
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82 | } |
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83 | |
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84 | /** |
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85 | * Load an ID certificate. |
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86 | */ |
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87 | static int _load_id(abac_id_t *cert) { |
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88 | abac_id_cert_t *id_cert = NULL; |
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89 | char *keyid = NULL; |
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90 | int ret; |
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91 | |
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92 | assert(cert); |
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93 | |
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94 | // get the key ID |
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95 | keyid = abac_id_keyid(cert); |
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96 | |
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97 | // if we already have this cert 'error' with success |
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98 | HASH_FIND_STR(id_certs, keyid, id_cert); |
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99 | if (id_cert != NULL) { |
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100 | ret = ABAC_CERT_SUCCESS; |
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101 | goto error; |
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102 | } |
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103 | |
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104 | ret = abac_id_still_valid(cert); |
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105 | if (!ret) { |
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106 | ret = ABAC_CERT_INVALID; |
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107 | goto error; |
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108 | } |
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109 | |
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110 | // success, add the key to the map of certificates |
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111 | id_cert = abac_xmalloc(sizeof(abac_id_cert_t)); |
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112 | id_cert->keyid = abac_xstrdup(keyid); |
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113 | id_cert->cert = cert; |
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114 | HASH_ADD_KEYPTR(hh, id_certs, id_cert->keyid, strlen(id_cert->keyid), id_cert); |
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115 | |
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116 | return ABAC_CERT_SUCCESS; |
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117 | |
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118 | error: |
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119 | if (keyid != NULL) free(keyid); |
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120 | return ret; |
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121 | } |
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122 | |
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123 | abac_id_t *abac_verifier_lookup_id(char *keyid) |
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124 | { |
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125 | abac_id_cert_t *id_cert; |
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126 | HASH_FIND_STR(id_certs, keyid, id_cert); |
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127 | if(id_cert == NULL) return NULL; |
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128 | return id_cert->cert; |
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129 | } |
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130 | |
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131 | /** |
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132 | * Load an ID cert from a file. |
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133 | */ |
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134 | int abac_verifier_load_id_file(char *filename) { |
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135 | // load the cert |
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136 | abac_id_t *cert = abac_id_from_file(filename); |
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137 | |
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138 | if (cert == NULL) |
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139 | return ABAC_CERT_INVALID; |
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140 | |
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141 | return _load_id(cert); |
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142 | } |
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143 | |
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144 | /** |
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145 | * Load an ID cert from a chunk. |
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146 | */ |
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147 | int abac_verifier_load_id_chunk(abac_chunk_t chunk) { |
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148 | |
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149 | // load the cert |
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150 | abac_id_t *cert= abac_id_from_chunk(chunk); |
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151 | |
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152 | if (cert == NULL) |
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153 | return ABAC_CERT_INVALID; |
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154 | return _load_id(cert); |
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155 | } |
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156 | |
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157 | /** |
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158 | * Load an attribute cert. |
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159 | * Returns true only if the certificate is valid and is issued by the proper |
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160 | * authority. |
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161 | */ |
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162 | static int _load_attribute_cert(abac_attribute_t *cert, abac_credential_t **cred_ret) { |
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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=NULL; |
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166 | int ret; |
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167 | |
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168 | char *attr_string=abac_attribute_role_string(cert); |
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169 | |
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170 | if(attr_string == NULL) { |
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171 | ret = ABAC_CERT_INVALID; |
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172 | goto error; |
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173 | } |
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174 | |
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175 | // split into head/tail parts |
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176 | char *head_tail[2]; |
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177 | abac_split(attr_string, "<-", head_tail, &ret); |
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178 | if (ret != 2) { |
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179 | ret = ABAC_CERT_INVALID; |
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180 | goto error; |
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181 | } |
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182 | |
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183 | // must be a role |
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184 | head_role = abac_role_from_string(head_tail[0]); |
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185 | if (head_role == NULL) goto error; |
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186 | if (!abac_role_is_role(head_role)) { |
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187 | ret = ABAC_CERT_INVALID; |
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188 | goto error; |
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189 | } |
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190 | |
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191 | // make sure the tail's valid too |
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192 | tail_role = abac_role_from_string(head_tail[1]); |
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193 | if (tail_role == NULL) { |
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194 | ret = ABAC_CERT_INVALID; |
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195 | goto error; |
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196 | } |
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197 | |
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198 | char *principal = abac_role_principal(head_role); |
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199 | HASH_FIND_STR(id_certs, principal, issuer); |
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200 | if (issuer == NULL) { |
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201 | ret = ABAC_CERT_MISSING_ISSUER; |
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202 | goto error; |
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203 | } |
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204 | |
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205 | // check if issuer is still valid |
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206 | if (!abac_id_still_valid(issuer->cert)) { |
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207 | ret = ABAC_CERT_INVALID_ISSUER; |
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208 | goto error; |
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209 | } |
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210 | |
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211 | // make sure principal match up with keyid |
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212 | if(!abac_id_has_keyid(issuer->cert,principal)) { |
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213 | ret = ABAC_CERT_BAD_PRINCIPAL; |
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214 | goto error; |
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215 | } |
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216 | |
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217 | // at this point we know we have a good attribute cert |
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218 | abac_credential_t *cred = abac_xmalloc(sizeof(abac_credential_t)); |
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219 | cred->head = head_role; |
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220 | cred->tail = tail_role; |
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221 | cred->cert = cert; |
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222 | /* acme's cert */ |
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223 | cred->issuer = abac_id_dup(issuer->cert); |
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224 | cred->refcount = 1; |
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225 | *cred_ret = cred; |
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226 | |
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227 | return ABAC_CERT_SUCCESS; |
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228 | |
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229 | error: |
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230 | if (head_role != NULL) abac_role_free(head_role); |
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231 | if (tail_role != NULL) abac_role_free(tail_role); |
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232 | |
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233 | return ret; |
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234 | } |
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235 | |
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236 | static int _load_attribute_certs(abac_list_t *attr_list, abac_list_t *cred_list) { |
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237 | |
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238 | int sz=abac_list_size(attr_list); |
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239 | abac_credential_t *cred_ret=NULL; |
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240 | abac_attribute_t *attr; |
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241 | if(sz) { |
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242 | abac_list_foreach(attr_list, attr, |
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243 | int ret=_load_attribute_cert(attr, &cred_ret); |
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244 | if(ret==ABAC_CERT_SUCCESS) { |
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245 | abac_list_add(cred_list, cred_ret); |
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246 | } |
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247 | ); |
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248 | } |
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249 | return sz; |
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250 | } |
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251 | |
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252 | /** |
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253 | * Load an attribute cert from a file. |
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254 | */ |
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255 | int abac_verifier_load_attribute_cert_file(char *filename, abac_list_t *cred_list) { |
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256 | |
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257 | // load the cert |
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258 | abac_list_t *attr_list = abac_attribute_certs_from_file(filename); |
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259 | |
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260 | if (abac_list_size(attr_list) == 0) |
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261 | return ABAC_CERT_INVALID; |
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262 | |
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263 | int ret=_load_attribute_certs(attr_list, cred_list); |
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264 | |
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265 | if(ret) return ABAC_CERT_SUCCESS; |
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266 | return ABAC_CERT_INVALID; |
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267 | } |
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268 | |
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269 | /** |
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270 | * Load an attribute cert from a chunk. |
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271 | */ |
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272 | int abac_verifier_load_attribute_cert_chunk(abac_chunk_t chunk, abac_list_t *cred_list) { |
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273 | |
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274 | // load the cert |
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275 | abac_list_t *attr_list = abac_attribute_certs_from_chunk(chunk); |
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276 | |
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277 | if (abac_list_size(attr_list) == 0) |
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278 | return ABAC_CERT_INVALID; |
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279 | return _load_attribute_certs(attr_list,cred_list); |
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280 | } |
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281 | |
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282 | /** |
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283 | * Return the head role. |
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284 | */ |
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285 | abac_role_t *abac_credential_head(abac_credential_t *cred) { |
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286 | return cred->head; |
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287 | } |
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288 | |
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289 | /** |
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290 | * Return the tail role. |
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291 | */ |
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292 | abac_role_t *abac_credential_tail(abac_credential_t *cred) { |
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293 | return cred->tail; |
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294 | } |
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295 | |
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296 | /** |
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297 | * Return the xml chunk of the attribute cert. |
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298 | */ |
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299 | abac_chunk_t abac_credential_attribute_cert(abac_credential_t *cred) { |
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300 | assert(cred); assert(cred->cert); |
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301 | return abac_attribute_cert(cred->cert); |
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302 | } |
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303 | |
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304 | /** |
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305 | * Return the chunk of the issuer cert. |
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306 | */ |
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307 | abac_chunk_t abac_credential_issuer_cert(abac_credential_t *cred) { |
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308 | assert(cred); assert(cred->issuer); |
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309 | abac_chunk_t ret= abac_id_in_PEM(cred->issuer); |
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310 | return ret; |
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311 | } |
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312 | |
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313 | /** |
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314 | * Increase the ref count of a credential. |
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315 | */ |
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316 | abac_credential_t *abac_credential_dup(abac_credential_t *cred) { |
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317 | assert(cred != NULL); |
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318 | |
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319 | ++cred->refcount; |
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320 | return cred; |
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321 | } |
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322 | |
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323 | /** |
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324 | * Decrease the reference count of a credential, freeing it when it reaches 0. |
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325 | */ |
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326 | void abac_credential_free(abac_credential_t *cred) { |
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327 | if (cred == NULL) |
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328 | return; |
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329 | |
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330 | --cred->refcount; |
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331 | if (cred->refcount > 0) |
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332 | return; |
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333 | |
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334 | abac_role_free(cred->head); |
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335 | abac_role_free(cred->tail); |
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336 | abac_attribute_free(cred->cert); |
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337 | abac_id_free(cred->issuer); |
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338 | |
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339 | free(cred); |
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340 | } |
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