src/http_auth.c

   1 #include "first.h"
   2
   3 #include "http_auth.h"
   4 #include "http_header.h"
   5
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9
  10 static http_auth_scheme_t http_auth_schemes[8];
  11
  12 const http_auth_scheme_t * http_auth_scheme_get (const buffer *name)
  13 {
  14     int i = 0;
  15     while (NULL != http_auth_schemes[i].name
  16            && 0 != strcmp(http_auth_schemes[i].name, name->ptr)) {
  17         ++i;
  18     }
  19     return (NULL != http_auth_schemes[i].name) ? http_auth_schemes+i : NULL;
  20 }
  21
  22 void http_auth_scheme_set (const http_auth_scheme_t *scheme)
  23 {
  24     unsigned int i = 0;
  25     while (NULL != http_auth_schemes[i].name) ++i;
  26     /*(must resize http_auth_schemes[] if too many different auth schemes)*/
  27     force_assert(i<(sizeof(http_auth_schemes)/sizeof(http_auth_scheme_t))-1);
  28     memcpy(http_auth_schemes+i, scheme, sizeof(http_auth_scheme_t));
  29 }
  30
  31
  32 static http_auth_backend_t http_auth_backends[12];
  33
  34 const http_auth_backend_t * http_auth_backend_get (const buffer *name)
  35 {
  36     int i = 0;
  37     while (NULL != http_auth_backends[i].name
  38            && 0 != strcmp(http_auth_backends[i].name, name->ptr)) {
  39         ++i;
  40     }
  41     return (NULL != http_auth_backends[i].name) ? http_auth_backends+i : NULL;
  42 }
  43
  44 void http_auth_backend_set (const http_auth_backend_t *backend)
  45 {
  46     unsigned int i = 0;
  47     while (NULL != http_auth_backends[i].name) ++i;
  48     /*(must resize http_auth_backends[] if too many different auth backends)*/
  49     force_assert(i<(sizeof(http_auth_backends)/sizeof(http_auth_backend_t))-1);
  50     memcpy(http_auth_backends+i, backend, sizeof(http_auth_backend_t));
  51 }
  52
  53
  54 int http_auth_const_time_memeq (const char *a, const size_t alen, const char *b, const size_t blen)
  55 {
  56     /* constant time memory compare, unless compiler figures it out
  57      * (similar to mod_secdownload.c:const_time_memeq()) */
  58     /* round to next multiple of 64 to avoid potentially leaking exact
  59      * password length when subject to high precision timing attacks) */
  60     size_t lim = ((alen >= blen ? alen : blen) + 0x3F) & ~0x3F;
  61     int diff = 0;
  62     for (size_t i = 0, j = 0; lim; --lim) {
  63         diff |= (a[i] ^ b[j]);
  64         i += (i < alen);
  65         j += (j < blen);
  66     }
  67     return (0 == diff);
  68 }
  69
  70
  71 void http_auth_dumbdata_reset (void)
  72 {
  73     memset(http_auth_schemes, 0, sizeof(http_auth_schemes));
  74     memset(http_auth_backends, 0, sizeof(http_auth_backends));
  75 }
  76
  77
  78 http_auth_require_t * http_auth_require_init (void)
  79 {
  80     http_auth_require_t *require = calloc(1, sizeof(http_auth_require_t));
  81     force_assert(NULL != require);
  82
  83     require->realm = buffer_init();
  84     require->valid_user = 0;
  85     require->user = array_init();
  86     require->group = array_init();
  87     require->host = array_init();
  88
  89     return require;
  90 }
  91
  92 void http_auth_require_free (http_auth_require_t * const require)
  93 {
  94     buffer_free(require->realm);
  95     array_free(require->user);
  96     array_free(require->group);
  97     array_free(require->host);
  98     free(require);
  99 }
 100
 101 /* (case-sensitive version of array.c:array_get_index(),
 102  *  and common case expects small num of allowed tokens,
 103  *  so it is reasonably performant to simply walk the array) */
 104 static int http_auth_array_contains (const array * const a, const char * const k, const size_t klen)
 105 {
 106     for (size_t i = 0, used = a->used; i < used; ++i) {
 107         if (buffer_is_equal_string(a->data[i]->key, k, klen)) {
 108             return 1;
 109         }
 110     }
 111     return 0;
 112 }
 113
 114 int http_auth_match_rules (const http_auth_require_t * const require, const char * const user, const char * const group, const char * const host)
 115 {
 116     if (NULL != user
 117         && (require->valid_user
 118             || http_auth_array_contains(require->user, user, strlen(user)))) {
 119         return 1; /* match */
 120     }
 121
 122     if (NULL != group
 123         && http_auth_array_contains(require->group, group, strlen(group))) {
 124         return 1; /* match */
 125     }
 126
 127     if (NULL != host
 128         && http_auth_array_contains(require->host, host, strlen(host))) {
 129         return 1; /* match */
 130     }
 131
 132     return 0; /* no match */
 133 }
 134
 135 void http_auth_setenv(connection *con, const char *username, size_t ulen, const char *auth_type, size_t alen) {
 136     http_header_env_set(con, CONST_STR_LEN("REMOTE_USER"), username, ulen);
 137     http_header_env_set(con, CONST_STR_LEN("AUTH_TYPE"), auth_type, alen);
 138 }
 139
 140 unsigned int http_auth_digest_len (int algo)
 141 {
 142     if (algo & (HTTP_AUTH_DIGEST_SHA256 | HTTP_AUTH_DIGEST_SHA512_256)) {
 143         /* HTTP_AUTH_DIGEST_SHA512_256_BINLEN */
 144         return HTTP_AUTH_DIGEST_SHA256_BINLEN;
 145     }
 146     if (algo & HTTP_AUTH_DIGEST_MD5) {
 147         return HTTP_AUTH_DIGEST_MD5_BINLEN;
 148     }
 149
 150     return 0;
 151 }
 152
 153 int http_auth_digest_hex2bin (const char *hexstr, size_t len, unsigned char *bin, size_t binlen)
 154 {
 155     /* validate and transform 32-byte MD5 hex string to 16-byte binary MD5,
 156      * or 64-byte SHA-256 or SHA-512-256 hex string to 32-byte binary digest */
 157     if (len > (binlen << 1)) return -1;
 158     for (int i = 0, ilen = (int)len; i < ilen; i+=2) {
 159         int hi = hexstr[i];
 160         int lo = hexstr[i+1];
 161         if ('0' <= hi && hi <= '9')                    hi -= '0';
 162         else if ((hi |= 0x20), 'a' <= hi && hi <= 'f') hi += -'a' + 10;
 163         else                                           return -1;
 164         if ('0' <= lo && lo <= '9')                    lo -= '0';
 165         else if ((lo |= 0x20), 'a' <= lo && lo <= 'f') lo += -'a' + 10;
 166         else                                           return -1;
 167         bin[(i >> 1)] = (unsigned char)((hi << 4) | lo);
 168     }
 169     return 0;
 170 }
 171
 172 #if 0
 173 int http_auth_md5_hex2lc (char *md5hex)
 174 {
 175     /* validate and transform 32-byte MD5 hex string to lowercase */
 176     int i;
 177     for (i = 0; md5hex[i]; ++i) {
 178         int c = md5hex[i];
 179         if ('0' <= c && c <= '9')                   continue;
 180         else if ((c |= 0x20), 'a' <= c && c <= 'f') md5hex[i] = c;
 181         else                                        return -1;
 182     }
 183     return (32 == i) ? 0 : -1; /*(Note: char *md5hex must be a 32-char string)*/
 184 }
 185 #endif