utils/mountd/auth.c

   1 /*
   2  * utils/mountd/auth.c
   3  *
   4  * Authentication procedures for mountd.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include <config.h>
  11 #endif
  12
  13 #include <sys/stat.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16 #include <errno.h>
  17 #include <unistd.h>
  18 #include "misc.h"
  19 #include "nfslib.h"
  20 #include "exportfs.h"
  21 #include "mountd.h"
  22 #include "xmalloc.h"
  23
  24 enum auth_error
  25 {
  26   bad_path,
  27   unknown_host,
  28   no_entry,
  29   not_exported,
  30   illegal_port,
  31   success
  32 };
  33
  34 static void             auth_fixpath(char *path);
  35 static char     *export_file = NULL;
  36 static nfs_export my_exp;
  37 static nfs_client my_client;
  38
  39 extern int new_cache;
  40 extern int use_ipaddr;
  41
  42 void
  43 auth_init(char *exports)
  44 {
  45
  46         export_file = exports;
  47         auth_reload();
  48         xtab_mount_write();
  49 }
  50
  51 /*
  52  * A client can match many different netgroups and it's tough to know
  53  * beforehand whether it will. If the concatenated string of netgroup
  54  * m_hostnames is >512 bytes, then enable the "use_ipaddr" mode. This
  55  * makes mountd change how it matches a client ip address when a mount
  56  * request comes in. It's more efficient at handling netgroups at the
  57  * expense of larger kernel caches.
  58  */
  59 static void
  60 check_useipaddr(void)
  61 {
  62         nfs_client *clp;
  63         int old_use_ipaddr = use_ipaddr;
  64         unsigned int len = 0;
  65
  66         /* add length of m_hostname + 1 for the comma */
  67         for (clp = clientlist[MCL_NETGROUP]; clp; clp = clp->m_next)
  68                 len += (strlen(clp->m_hostname) + 1);
  69
  70         if (len > (NFSCLNT_IDMAX / 2))
  71                 use_ipaddr = 1;
  72         else
  73                 use_ipaddr = 0;
  74
  75         if (use_ipaddr != old_use_ipaddr)
  76                 cache_flush(1);
  77 }
  78
  79 unsigned int
  80 auth_reload()
  81 {
  82         struct stat             stb;
  83         static ino_t            last_inode;
  84         static int              last_fd;
  85         static unsigned int     counter;
  86         int                     fd;
  87
  88         if ((fd = open(_PATH_ETAB, O_RDONLY)) < 0) {
  89                 xlog(L_FATAL, "couldn't open %s", _PATH_ETAB);
  90         } else if (fstat(fd, &stb) < 0) {
  91                 xlog(L_FATAL, "couldn't stat %s", _PATH_ETAB);
  92         } else if (stb.st_ino == last_inode) {
  93                 close(fd);
  94                 return counter;
  95         } else {
  96                 close(last_fd);
  97                 last_fd = fd;
  98                 last_inode = stb.st_ino;
  99         }
 100
 101         export_freeall();
 102         memset(&my_client, 0, sizeof(my_client));
 103         xtab_export_read();
 104         check_useipaddr();
 105         ++counter;
 106
 107         return counter;
 108 }
 109
 110 static nfs_export *
 111 auth_authenticate_internal(char *what, struct sockaddr_in *caller,
 112                            char *path, struct hostent *hp,
 113                            enum auth_error *error)
 114 {
 115         nfs_export              *exp;
 116
 117         if (new_cache) {
 118                 int i;
 119                 /* return static nfs_export with details filled in */
 120                 char *n;
 121                 free(my_client.m_hostname);
 122                 if (use_ipaddr) {
 123                         my_client.m_hostname =
 124                                 strdup(inet_ntoa(caller->sin_addr));
 125                 } else {
 126                         n = client_compose(hp);
 127                         *error = unknown_host;
 128                         if (!n)
 129                                 my_client.m_hostname = NULL;
 130                         else if (*n)
 131                                 my_client.m_hostname = n;
 132                         else {
 133                                 free(n);
 134                                 my_client.m_hostname = strdup("DEFAULT");
 135                         }
 136                 }
 137                 if (my_client.m_hostname == NULL)
 138                         return NULL;
 139                 my_client.m_naddr = 1;
 140                 my_client.m_addrlist[0] = caller->sin_addr;
 141                 my_exp.m_client = &my_client;
 142
 143                 exp = NULL;
 144                 for (i = 0; !exp && i < MCL_MAXTYPES; i++)
 145                         for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 146                                 if (strcmp(path, exp->m_export.e_path))
 147                                         continue;
 148                                 if (!use_ipaddr && !client_member(my_client.m_hostname, exp->m_client->m_hostname))
 149                                         continue;
 150                                 if (use_ipaddr && !client_check(exp->m_client, hp))
 151                                         continue;
 152                                 break;
 153                         }
 154                 *error = not_exported;
 155                 if (!exp)
 156                         return exp;
 157
 158                 my_exp.m_export = exp->m_export;
 159                 exp = &my_exp;
 160
 161         } else {
 162                 if (!(exp = export_find(hp, path))) {
 163                         *error = no_entry;
 164                         return NULL;
 165                 }
 166                 if (!exp->m_mayexport) {
 167                         *error = not_exported;
 168                         return NULL;
 169                 }
 170         }
 171         if (!(exp->m_export.e_flags & NFSEXP_INSECURE_PORT) &&
 172                      ntohs(caller->sin_port) >= IPPORT_RESERVED) {
 173                 *error = illegal_port;
 174                 return NULL;
 175         }
 176         *error = success;
 177
 178         return exp;
 179 }
 180
 181 nfs_export *
 182 auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
 183 {
 184         nfs_export      *exp = NULL;
 185         char            epath[MAXPATHLEN+1];
 186         char            *p = NULL;
 187         struct hostent  *hp = NULL;
 188         struct in_addr  addr = caller->sin_addr;
 189         enum auth_error error = bad_path;
 190
 191         if (path [0] != '/') {
 192                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 193                      what, inet_ntoa(addr), path);
 194                 return exp;
 195         }
 196
 197         strncpy(epath, path, sizeof (epath) - 1);
 198         epath[sizeof (epath) - 1] = '\0';
 199         auth_fixpath(epath); /* strip duplicate '/' etc */
 200
 201         hp = client_resolve(caller->sin_addr);
 202         if (!hp)
 203                 return exp;
 204
 205         /* Try the longest matching exported pathname. */
 206         while (1) {
 207                 exp = auth_authenticate_internal(what, caller, epath,
 208                                                  hp, &error);
 209                 if (exp || (error != not_exported && error != no_entry))
 210                         break;
 211                 /* We have to treat the root, "/", specially. */
 212                 if (p == &epath[1]) break;
 213                 p = strrchr(epath, '/');
 214                 if (p == epath) p++;
 215                 *p = '\0';
 216         }
 217
 218         switch (error) {
 219         case bad_path:
 220                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 221                      what, inet_ntoa(addr), path);
 222                 break;
 223
 224         case unknown_host:
 225                 xlog(L_WARNING, "refused %s request from %s for %s (%s): unmatched host",
 226                      what, inet_ntoa(addr), path, epath);
 227                 break;
 228
 229         case no_entry:
 230                 xlog(L_WARNING, "refused %s request from %s for %s (%s): no export entry",
 231                      what, hp->h_name, path, epath);
 232                 break;
 233
 234         case not_exported:
 235                 xlog(L_WARNING, "refused %s request from %s for %s (%s): not exported",
 236                      what, hp->h_name, path, epath);
 237                 break;
 238
 239         case illegal_port:
 240                 xlog(L_WARNING, "refused %s request from %s for %s (%s): illegal port %d",
 241                      what, hp->h_name, path, epath, ntohs(caller->sin_port));
 242                 break;
 243
 244         case success:
 245                 xlog(L_NOTICE, "authenticated %s request from %s:%d for %s (%s)",
 246                      what, hp->h_name, ntohs(caller->sin_port), path, epath);
 247                 break;
 248         default:
 249                 xlog(L_NOTICE, "%s request from %s:%d for %s (%s) gave %d",
 250                      what, hp->h_name, ntohs(caller->sin_port), path, epath, error);
 251         }
 252
 253         if (hp)
 254                 free (hp);
 255
 256         return exp;
 257 }
 258
 259 static void
 260 auth_fixpath(char *path)
 261 {
 262         char    *sp, *cp;
 263
 264         for (sp = cp = path; *sp; sp++) {
 265                 if (*sp != '/' || sp[1] != '/')
 266                         *cp++ = *sp;
 267         }
 268         while (cp > path+1 && cp[-1] == '/')
 269                 cp--;
 270         *cp = '\0';
 271 }