user_list.c

   1 /*
   2  * Copyright (C) 2006-2009 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 #include <openssl/rc4.h>
  13
  14 #include "para.h"
  15 #include "error.h"
  16 #include "crypt.h"
  17 #include "fd.h"
  18 #include "string.h"
  19 #include "list.h"
  20 #include "user_list.h"
  21 #include "rc4.h"
  22
  23 static struct list_head user_list;
  24
  25 /*
  26  * Fill the list of users known to para_server.
  27  *
  28  * Populates a linked list of all users in \a user_list_file.  Returns on
  29  * success, calls exit() on errors.
  30  */
  31 static void populate_user_list(char *user_list_file)
  32 {
  33         int ret = -E_USERLIST;
  34         FILE *file_ptr = fopen(user_list_file, "r");
  35
  36         if (!file_ptr)
  37                 goto err;
  38         for (;;) {
  39                 int num;
  40                 char line[255];
  41                 /* keyword, name, key, perms */
  42                 char w[255], n[255], k[255], p[255], tmp[4][255];
  43                 struct user *u;
  44                 RSA *rsa;
  45
  46                 ret = para_fgets(line, MAXLINE, file_ptr);
  47                 if (ret <= 0)
  48                         break;
  49                 if (sscanf(line,"%200s %200s %200s %200s", w, n, k, p) < 3)
  50                         continue;
  51                 if (strcmp(w, "user"))
  52                         continue;
  53                 PARA_DEBUG_LOG("found entry for user %s\n", n);
  54                 ret = get_rsa_key(k, &rsa, LOAD_PUBLIC_KEY);
  55                 if (ret < 0) {
  56                         PARA_NOTICE_LOG("skipping entry for user %s: %s\n", n,
  57                                 para_strerror(-ret));
  58                         continue;
  59                 }
  60                 /*
  61                  * In order to encrypt len := CHALLENGE_SIZE + 2 * RC4_KEY_LEN
  62                  * bytes using RSA_public_encrypt() with EME-OAEP padding mode,
  63                  * RSA_size(rsa) must be greater than len + 41. So ignore keys
  64                  * which are too short. For details see RSA_public_encrypt(3).
  65                  */
  66                 if (ret <= CHALLENGE_SIZE + 2 * RC4_KEY_LEN + 41) {
  67                         PARA_WARNING_LOG("rsa key %s too short (%d)\n",
  68                                 k, ret);
  69                         rsa_free(rsa);
  70                         continue;
  71                 }
  72                 u = para_malloc(sizeof(*u));
  73                 u->name = para_strdup(n);
  74                 u->rsa = rsa;
  75                 u->perms = 0;
  76                 num = sscanf(p, "%200[A-Z_],%200[A-Z_],%200[A-Z_],%200[A-Z_]",
  77                         tmp[0], tmp[1], tmp[2], tmp[3]);
  78                 PARA_DEBUG_LOG("found %i perm entries\n", num);
  79                 while (num > 0) {
  80                         num--;
  81                         if (!strcmp(tmp[num], "VSS_READ"))
  82                                 u->perms |= VSS_READ;
  83                         else if (!strcmp(tmp[num], "VSS_WRITE"))
  84                                 u->perms |= VSS_WRITE;
  85                         else if (!strcmp(tmp[num], "AFS_READ"))
  86                                 u->perms |= AFS_READ;
  87                         else if (!strcmp(tmp[num], "AFS_WRITE"))
  88                                 u->perms |= AFS_WRITE;
  89                         else /* unknown permission */
  90                                 PARA_WARNING_LOG("ignoring unknown permission: %s\n",
  91                                         tmp[num]);
  92                 }
  93                 para_list_add(&u->node, &user_list);
  94         }
  95         fclose(file_ptr);
  96         if (ret >= 0)
  97                 return;
  98 err:
  99         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 100         exit(EXIT_FAILURE);
 101 }
 102
 103 /**
 104  * Initialize the list of users allowed to connect to to para_server.
 105  *
 106  * \param user_list_file The file containing access information.
 107  *
 108  * If this function is called for the second time, the contents of the
 109  * previous call are discarded, i.e. the user list is reloaded.
 110  */
 111 void init_user_list(char *user_list_file)
 112 {
 113         struct user *u, *tmp;
 114         static int initialized;
 115
 116         if (initialized) {
 117                 list_for_each_entry_safe(u, tmp, &user_list, node) {
 118                         list_del(&u->node);
 119                         free(u->name);
 120                         rsa_free(u->rsa);
 121                         free(u);
 122                 }
 123         } else
 124                 INIT_LIST_HEAD(&user_list);
 125         initialized = 1;
 126         populate_user_list(user_list_file);
 127 }
 128
 129 /**
 130  * Lookup a user in the user list.
 131  *
 132  * \param name The name of the user.
 133  *
 134  * \return A pointer to the corresponding user struct if the user was found, \p
 135  * NULL otherwise.
 136  */
 137 struct user *lookup_user(const char *name)
 138 {
 139         struct user *u;
 140         list_for_each_entry(u, &user_list, node) {
 141                 if (strcmp(u->name, name))
 142                         continue;
 143                 return u;
 144         }
 145         return NULL;
 146 }