user_list.c

   1 /*
   2  * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file user_list.c User handling for para_server. */
   8
   9 #include <regex.h>
  10 #include <sys/types.h>
  11 #include <dirent.h>
  12
  13 #include "para.h"
  14 #include "error.h"
  15 #include "crypt.h"
  16 #include "fd.h"
  17 #include "string.h"
  18 #include "list.h"
  19 #include "user_list.h"
  20 #include "rc4.h"
  21
  22 static struct list_head user_list;
  23
  24 /*
  25  * Fill the list of users known to para_server.
  26  *
  27  * Populates a linked list of all users in \a user_list_file.  Returns on
  28  * success, calls exit() on errors.
  29  */
  30 static void populate_user_list(char *user_list_file)
  31 {
  32         int ret = -E_USERLIST;
  33         FILE *file_ptr = fopen(user_list_file, "r");
  34
  35         if (!file_ptr)
  36                 goto err;
  37         for (;;) {
  38                 int num;
  39                 char line[255];
  40                 /* keyword, name, key, perms */
  41                 char w[255], n[255], k[255], p[255], tmp[4][255];
  42                 struct user *u;
  43                 struct asymmetric_key *pubkey;
  44
  45                 ret = para_fgets(line, sizeof(line), file_ptr);
  46                 if (ret <= 0)
  47                         break;
  48                 if (sscanf(line,"%200s %200s %200s %200s", w, n, k, p) < 3)
  49                         continue;
  50                 if (strcmp(w, "user"))
  51                         continue;
  52                 PARA_DEBUG_LOG("found entry for user %s\n", n);
  53                 ret = get_asymmetric_key(k, LOAD_PUBLIC_KEY, &pubkey);
  54                 if (ret < 0) {
  55                         PARA_NOTICE_LOG("skipping entry for user %s: %s\n", n,
  56                                 para_strerror(-ret));
  57                         continue;
  58                 }
  59                 /*
  60                  * In order to encrypt len := CHALLENGE_SIZE + 2 * RC4_KEY_LEN
  61                  * bytes using RSA_public_encrypt() with EME-OAEP padding mode,
  62                  * RSA_size(rsa) must be greater than len + 41. So ignore keys
  63                  * which are too short. For details see RSA_public_encrypt(3).
  64                  */
  65                 if (ret <= CHALLENGE_SIZE + 2 * RC4_KEY_LEN + 41) {
  66                         PARA_WARNING_LOG("public key %s too short (%d)\n",
  67                                 k, ret);
  68                         free_asymmetric_key(pubkey);
  69                         continue;
  70                 }
  71                 u = para_malloc(sizeof(*u));
  72                 u->name = para_strdup(n);
  73                 u->pubkey = pubkey;
  74                 u->perms = 0;
  75                 num = sscanf(p, "%200[A-Z_],%200[A-Z_],%200[A-Z_],%200[A-Z_]",
  76                         tmp[0], tmp[1], tmp[2], tmp[3]);
  77                 PARA_DEBUG_LOG("found %i perm entries\n", num);
  78                 while (num > 0) {
  79                         num--;
  80                         if (!strcmp(tmp[num], "VSS_READ"))
  81                                 u->perms |= VSS_READ;
  82                         else if (!strcmp(tmp[num], "VSS_WRITE"))
  83                                 u->perms |= VSS_WRITE;
  84                         else if (!strcmp(tmp[num], "AFS_READ"))
  85                                 u->perms |= AFS_READ;
  86                         else if (!strcmp(tmp[num], "AFS_WRITE"))
  87                                 u->perms |= AFS_WRITE;
  88                         else /* unknown permission */
  89                                 PARA_WARNING_LOG("ignoring unknown permission: %s\n",
  90                                         tmp[num]);
  91                 }
  92                 para_list_add(&u->node, &user_list);
  93         }
  94         fclose(file_ptr);
  95         if (ret >= 0)
  96                 return;
  97 err:
  98         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
  99         exit(EXIT_FAILURE);
 100 }
 101
 102 /**
 103  * Initialize the list of users allowed to connect to to para_server.
 104  *
 105  * \param user_list_file The file containing access information.
 106  *
 107  * If this function is called for the second time, the contents of the
 108  * previous call are discarded, i.e. the user list is reloaded.
 109  */
 110 void init_user_list(char *user_list_file)
 111 {
 112         struct user *u, *tmp;
 113         static int initialized;
 114
 115         if (initialized) {
 116                 list_for_each_entry_safe(u, tmp, &user_list, node) {
 117                         list_del(&u->node);
 118                         free(u->name);
 119                         free_asymmetric_key(u->pubkey);
 120                         free(u);
 121                 }
 122         } else
 123                 INIT_LIST_HEAD(&user_list);
 124         initialized = 1;
 125         populate_user_list(user_list_file);
 126 }
 127
 128 /**
 129  * Lookup a user in the user list.
 130  *
 131  * \param name The name of the user.
 132  *
 133  * \return A pointer to the corresponding user struct if the user was found, \p
 134  * NULL otherwise.
 135  */
 136 struct user *lookup_user(const char *name)
 137 {
 138         struct user *u;
 139         list_for_each_entry(u, &user_list, node) {
 140                 if (strcmp(u->name, name))
 141                         continue;
 142                 return u;
 143         }
 144         return NULL;
 145 }