user_list.c

   1 /*
   2  * Copyright (C) 2006-2013 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
  12 #include "para.h"
  13 #include "error.h"
  14 #include "crypt.h"
  15 #include "fd.h"
  16 #include "string.h"
  17 #include "list.h"
  18 #include "user_list.h"
  19
  20 static struct list_head user_list;
  21
  22 /*
  23  * Fill the list of users known to para_server.
  24  *
  25  * Populates a linked list of all users in \a user_list_file.  Returns on
  26  * success, calls exit() on errors.
  27  */
  28 static void populate_user_list(char *user_list_file)
  29 {
  30         int ret = -E_USERLIST;
  31         FILE *file_ptr = fopen(user_list_file, "r");
  32
  33         if (!file_ptr)
  34                 goto err;
  35         for (;;) {
  36                 int num;
  37                 char line[255];
  38                 /* keyword, name, key, perms */
  39                 char w[255], n[255], k[255], p[255], tmp[4][255];
  40                 struct user *u;
  41                 struct asymmetric_key *pubkey;
  42
  43                 ret = para_fgets(line, sizeof(line), file_ptr);
  44                 if (ret <= 0)
  45                         break;
  46                 if (sscanf(line,"%200s %200s %200s %200s", w, n, k, p) < 3)
  47                         continue;
  48                 if (strcmp(w, "user"))
  49                         continue;
  50                 PARA_DEBUG_LOG("found entry for user %s\n", n);
  51                 ret = get_asymmetric_key(k, LOAD_PUBLIC_KEY, &pubkey);
  52                 if (ret < 0) {
  53                         PARA_NOTICE_LOG("skipping entry for user %s: %s\n", n,
  54                                 para_strerror(-ret));
  55                         continue;
  56                 }
  57                 /*
  58                  * In order to encrypt len := CHALLENGE_SIZE + 2 * SESSION_KEY_LEN
  59                  * bytes using RSA_public_encrypt() with EME-OAEP padding mode,
  60                  * RSA_size(rsa) must be greater than len + 41. So ignore keys
  61                  * which are too short. For details see RSA_public_encrypt(3).
  62                  */
  63                 if (ret <= CHALLENGE_SIZE + 2 * SESSION_KEY_LEN + 41) {
  64                         PARA_WARNING_LOG("public key %s too short (%d)\n",
  65                                 k, ret);
  66                         free_asymmetric_key(pubkey);
  67                         continue;
  68                 }
  69                 u = para_malloc(sizeof(*u));
  70                 u->name = para_strdup(n);
  71                 u->pubkey = pubkey;
  72                 u->perms = 0;
  73                 num = sscanf(p, "%200[A-Z_],%200[A-Z_],%200[A-Z_],%200[A-Z_]",
  74                         tmp[0], tmp[1], tmp[2], tmp[3]);
  75                 PARA_DEBUG_LOG("found %i perm entries\n", num);
  76                 while (num > 0) {
  77                         num--;
  78                         if (!strcmp(tmp[num], "VSS_READ"))
  79                                 u->perms |= VSS_READ;
  80                         else if (!strcmp(tmp[num], "VSS_WRITE"))
  81                                 u->perms |= VSS_WRITE;
  82                         else if (!strcmp(tmp[num], "AFS_READ"))
  83                                 u->perms |= AFS_READ;
  84                         else if (!strcmp(tmp[num], "AFS_WRITE"))
  85                                 u->perms |= AFS_WRITE;
  86                         else /* unknown permission */
  87                                 PARA_WARNING_LOG("ignoring unknown permission: %s\n",
  88                                         tmp[num]);
  89                 }
  90                 para_list_add(&u->node, &user_list);
  91         }
  92         fclose(file_ptr);
  93         if (ret >= 0)
  94                 return;
  95 err:
  96         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
  97         exit(EXIT_FAILURE);
  98 }
  99
 100 /**
 101  * Initialize the list of users allowed to connect to to para_server.
 102  *
 103  * \param user_list_file The file containing access information.
 104  *
 105  * If this function is called for the second time, the contents of the
 106  * previous call are discarded, i.e. the user list is reloaded.
 107  */
 108 void init_user_list(char *user_list_file)
 109 {
 110         struct user *u, *tmp;
 111         static int initialized;
 112
 113         if (initialized) {
 114                 list_for_each_entry_safe(u, tmp, &user_list, node) {
 115                         list_del(&u->node);
 116                         free(u->name);
 117                         free_asymmetric_key(u->pubkey);
 118                         free(u);
 119                 }
 120         } else
 121                 INIT_LIST_HEAD(&user_list);
 122         initialized = 1;
 123         populate_user_list(user_list_file);
 124 }
 125
 126 /**
 127  * Lookup a user in the user list.
 128  *
 129  * \param name The name of the user.
 130  *
 131  * \return A pointer to the corresponding user struct if the user was found, \p
 132  * NULL otherwise.
 133  */
 134 struct user *lookup_user(const char *name)
 135 {
 136         struct user *u;
 137         list_for_each_entry(u, &user_list, node) {
 138                 if (strcmp(u->name, name))
 139                         continue;
 140                 return u;
 141         }
 142         return NULL;
 143 }