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 #include "v4root.h"
  24
  25 enum auth_error
  26 {
  27   bad_path,
  28   unknown_host,
  29   no_entry,
  30   not_exported,
  31   illegal_port,
  32   success
  33 };
  34
  35 static void             auth_fixpath(char *path);
  36 static char     *export_file = NULL;
  37 static nfs_export my_exp;
  38 static nfs_client my_client;
  39
  40 extern int new_cache;
  41 extern int use_ipaddr;
  42
  43 void
  44 auth_init(char *exports)
  45 {
  46
  47         export_file = exports;
  48         auth_reload();
  49         xtab_mount_write();
  50 }
  51
  52 /*
  53  * A client can match many different netgroups and it's tough to know
  54  * beforehand whether it will. If the concatenated string of netgroup
  55  * m_hostnames is >512 bytes, then enable the "use_ipaddr" mode. This
  56  * makes mountd change how it matches a client ip address when a mount
  57  * request comes in. It's more efficient at handling netgroups at the
  58  * expense of larger kernel caches.
  59  */
  60 static void
  61 check_useipaddr(void)
  62 {
  63         nfs_client *clp;
  64         int old_use_ipaddr = use_ipaddr;
  65         unsigned int len = 0;
  66
  67         /* add length of m_hostname + 1 for the comma */
  68         for (clp = clientlist[MCL_NETGROUP]; clp; clp = clp->m_next)
  69                 len += (strlen(clp->m_hostname) + 1);
  70
  71         if (len > (NFSCLNT_IDMAX / 2))
  72                 use_ipaddr = 1;
  73         else
  74                 use_ipaddr = 0;
  75
  76         if (use_ipaddr != old_use_ipaddr)
  77                 cache_flush(1);
  78 }
  79
  80 unsigned int
  81 auth_reload()
  82 {
  83         struct stat             stb;
  84         static ino_t            last_inode;
  85         static int              last_fd;
  86         static unsigned int     counter;
  87         int                     fd;
  88
  89         if ((fd = open(_PATH_ETAB, O_RDONLY)) < 0) {
  90                 xlog(L_FATAL, "couldn't open %s", _PATH_ETAB);
  91         } else if (fstat(fd, &stb) < 0) {
  92                 xlog(L_FATAL, "couldn't stat %s", _PATH_ETAB);
  93         } else if (stb.st_ino == last_inode) {
  94                 close(fd);
  95                 return counter;
  96         } else {
  97                 close(last_fd);
  98                 last_fd = fd;
  99                 last_inode = stb.st_ino;
 100         }
 101
 102         export_freeall();
 103         memset(&my_client, 0, sizeof(my_client));
 104         xtab_export_read();
 105         check_useipaddr();
 106         v4root_set();
 107
 108         ++counter;
 109
 110         return counter;
 111 }
 112
 113 static nfs_export *
 114 auth_authenticate_internal(char *what, struct sockaddr_in *caller,
 115                            char *path, struct hostent *hp,
 116                            enum auth_error *error)
 117 {
 118         nfs_export              *exp;
 119
 120         if (new_cache) {
 121                 int i;
 122                 /* return static nfs_export with details filled in */
 123                 char *n;
 124                 free(my_client.m_hostname);
 125                 if (use_ipaddr) {
 126                         my_client.m_hostname =
 127                                 strdup(inet_ntoa(caller->sin_addr));
 128                 } else {
 129                         n = client_compose(hp);
 130                         *error = unknown_host;
 131                         if (!n)
 132                                 my_client.m_hostname = NULL;
 133                         else if (*n)
 134                                 my_client.m_hostname = n;
 135                         else {
 136                                 free(n);
 137                                 my_client.m_hostname = strdup("DEFAULT");
 138                         }
 139                 }
 140                 if (my_client.m_hostname == NULL)
 141                         return NULL;
 142                 my_client.m_naddr = 1;
 143                 my_client.m_addrlist[0] = caller->sin_addr;
 144                 my_exp.m_client = &my_client;
 145
 146                 exp = NULL;
 147                 for (i = 0; !exp && i < MCL_MAXTYPES; i++)
 148                         for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 149                                 if (strcmp(path, exp->m_export.e_path))
 150                                         continue;
 151                                 if (!use_ipaddr && !client_member(my_client.m_hostname, exp->m_client->m_hostname))
 152                                         continue;
 153                                 if (use_ipaddr && !client_check(exp->m_client, hp))
 154                                         continue;
 155                                 break;
 156                         }
 157                 *error = not_exported;
 158                 if (!exp)
 159                         return exp;
 160
 161                 my_exp.m_export = exp->m_export;
 162                 exp = &my_exp;
 163
 164         } else {
 165                 if (!(exp = export_find(hp, path))) {
 166                         *error = no_entry;
 167                         return NULL;
 168                 }
 169                 if (!exp->m_mayexport) {
 170                         *error = not_exported;
 171                         return NULL;
 172                 }
 173         }
 174         if (!(exp->m_export.e_flags & NFSEXP_INSECURE_PORT) &&
 175                      ntohs(caller->sin_port) >= IPPORT_RESERVED) {
 176                 *error = illegal_port;
 177                 return NULL;
 178         }
 179         *error = success;
 180
 181         return exp;
 182 }
 183
 184 nfs_export *
 185 auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
 186 {
 187         nfs_export      *exp = NULL;
 188         char            epath[MAXPATHLEN+1];
 189         char            *p = NULL;
 190         struct hostent  *hp = NULL;
 191         struct in_addr  addr = caller->sin_addr;
 192         enum auth_error error = bad_path;
 193
 194         if (path [0] != '/') {
 195                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 196                      what, inet_ntoa(addr), path);
 197                 return exp;
 198         }
 199
 200         strncpy(epath, path, sizeof (epath) - 1);
 201         epath[sizeof (epath) - 1] = '\0';
 202         auth_fixpath(epath); /* strip duplicate '/' etc */
 203
 204         hp = client_resolve(caller->sin_addr);
 205         if (!hp)
 206                 return exp;
 207
 208         /* Try the longest matching exported pathname. */
 209         while (1) {
 210                 exp = auth_authenticate_internal(what, caller, epath,
 211                                                  hp, &error);
 212                 if (exp || (error != not_exported && error != no_entry))
 213                         break;
 214                 /* We have to treat the root, "/", specially. */
 215                 if (p == &epath[1]) break;
 216                 p = strrchr(epath, '/');
 217                 if (p == epath) p++;
 218                 *p = '\0';
 219         }
 220
 221         switch (error) {
 222         case bad_path:
 223                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 224                      what, inet_ntoa(addr), path);
 225                 break;
 226
 227         case unknown_host:
 228                 xlog(L_WARNING, "refused %s request from %s for %s (%s): unmatched host",
 229                      what, inet_ntoa(addr), path, epath);
 230                 break;
 231
 232         case no_entry:
 233                 xlog(L_WARNING, "refused %s request from %s for %s (%s): no export entry",
 234                      what, hp->h_name, path, epath);
 235                 break;
 236
 237         case not_exported:
 238                 xlog(L_WARNING, "refused %s request from %s for %s (%s): not exported",
 239                      what, hp->h_name, path, epath);
 240                 break;
 241
 242         case illegal_port:
 243                 xlog(L_WARNING, "refused %s request from %s for %s (%s): illegal port %d",
 244                      what, hp->h_name, path, epath, ntohs(caller->sin_port));
 245                 break;
 246
 247         case success:
 248                 xlog(L_NOTICE, "authenticated %s request from %s:%d for %s (%s)",
 249                      what, hp->h_name, ntohs(caller->sin_port), path, epath);
 250                 break;
 251         default:
 252                 xlog(L_NOTICE, "%s request from %s:%d for %s (%s) gave %d",
 253                      what, hp->h_name, ntohs(caller->sin_port), path, epath, error);
 254         }
 255
 256         if (hp)
 257                 free (hp);
 258
 259         return exp;
 260 }
 261
 262 static void
 263 auth_fixpath(char *path)
 264 {
 265         char    *sp, *cp;
 266
 267         for (sp = cp = path; *sp; sp++) {
 268                 if (*sp != '/' || sp[1] != '/')
 269                         *cp++ = *sp;
 270         }
 271         while (cp > path+1 && cp[-1] == '/')
 272                 cp--;
 273         *cp = '\0';
 274 }