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