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 #include "config.h"
  10
  11 #include <sys/stat.h>
  12 #include <netinet/in.h>
  13 #include <arpa/inet.h>
  14 #include <errno.h>
  15 #include "misc.h"
  16 #include "nfslib.h"
  17 #include "exportfs.h"
  18 #include "mountd.h"
  19 #include "xmalloc.h"
  20
  21 enum auth_error
  22 {
  23   bad_path,
  24   unknown_host,
  25   no_entry,
  26   not_exported,
  27   illegal_port,
  28   faked_hostent,
  29   no_forward_dns,
  30   success
  31 };
  32
  33 static void             auth_fixpath(char *path);
  34 static nfs_export*      auth_authenticate_internal
  35   (char *what, struct sockaddr_in *caller, char *path,
  36    struct hostent **hpp, enum auth_error *error);
  37 static char     *export_file = NULL;
  38
  39 void
  40 auth_init(char *exports)
  41 {
  42
  43         export_file = exports;
  44         auth_reload();
  45         xtab_mount_write();
  46 }
  47
  48 int
  49 auth_reload()
  50 {
  51         struct stat             stb;
  52         static time_t           last_modified = 0;
  53
  54         if (stat(_PATH_ETAB, &stb) < 0)
  55                 xlog(L_FATAL, "couldn't stat %s", _PATH_ETAB);
  56         if (stb.st_mtime == last_modified)
  57                 return 0;
  58         last_modified = stb.st_mtime;
  59
  60         export_freeall();
  61         // export_read(export_file);
  62         xtab_export_read();
  63
  64         return 1;
  65 }
  66
  67 static nfs_export *
  68 auth_authenticate_internal(char *what, struct sockaddr_in *caller,
  69                            char *path, struct hostent **hpp,
  70                            enum auth_error *error)
  71 {
  72         struct in_addr          addr = caller->sin_addr;
  73         nfs_export              *exp;
  74
  75         if (path[0] != '/') {
  76                 *error = bad_path;
  77                 return NULL;
  78         }
  79         auth_fixpath(path);
  80
  81         /* First try it w/o doing a hostname lookup... */
  82         *hpp = get_hostent((const char *)&addr, sizeof(addr), AF_INET);
  83         exp = export_find(*hpp, path);
  84
  85         if (!exp) {
  86             /* Ok, that didn't fly.  Try it with a reverse lookup. */
  87             free (*hpp);
  88             *hpp = gethostbyaddr((const char *)&addr, sizeof(addr),
  89                                  AF_INET);
  90             if (!(*hpp)) {
  91                 *error = no_entry;
  92                 return NULL;
  93             } else {
  94                 /* must make sure the hostent is authorative. */
  95                 char **sp;
  96                 struct hostent *forward = NULL;
  97                 char *tmpname;
  98
  99                 tmpname = xstrdup((*hpp)->h_name);
 100                 if (tmpname) {
 101                         forward = gethostbyname(tmpname);
 102                         free(tmpname);
 103                 }
 104                 if (forward) {
 105                         /* now make sure the "addr" is in the list */
 106                         for (sp = forward->h_addr_list ; *sp ; sp++) {
 107                                 if (memcmp(*sp, &addr, forward->h_length)==0)
 108                                         break;
 109                         }
 110
 111                         if (!*sp) {
 112                                 /* it was a FAKE */
 113                                 *error = faked_hostent;
 114                                 *hpp = hostent_dup (*hpp);
 115                                 return NULL;
 116                         }
 117                         *hpp = hostent_dup (forward);
 118                 }
 119                 else {
 120                         /* never heard of it. misconfigured DNS? */
 121                         *error = no_forward_dns;
 122                         *hpp = hostent_dup (*hpp);
 123                         return NULL;
 124                 }
 125             }
 126
 127             if (!(exp = export_find(*hpp, path))) {
 128                 *error = no_entry;
 129                 return NULL;
 130             }
 131         }
 132
 133         if (!exp->m_mayexport) {
 134                 *error = not_exported;
 135                 return NULL;
 136         }
 137
 138         if (!(exp->m_export.e_flags & NFSEXP_INSECURE_PORT) &&
 139             (ntohs(caller->sin_port) <  IPPORT_RESERVED/2 ||
 140              ntohs(caller->sin_port) >= IPPORT_RESERVED)) {
 141                 *error = illegal_port;
 142                 return NULL;
 143         }
 144
 145         *error = success;
 146
 147         return exp;
 148 }
 149
 150 nfs_export *
 151 auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
 152 {
 153         nfs_export      *exp = NULL;
 154         char            epath[MAXPATHLEN+1];
 155         char            *p = NULL;
 156         struct hostent  *hp = NULL;
 157         struct in_addr  addr = caller->sin_addr;
 158         enum auth_error error;
 159
 160         if (path [0] != '/') return exp;
 161
 162         strncpy(epath, path, sizeof (epath) - 1);
 163         epath[sizeof (epath) - 1] = '\0';
 164
 165         /* Try the longest matching exported pathname. */
 166         while (1) {
 167                 if (hp) {
 168                         free (hp);
 169                         hp = NULL;
 170                 }
 171                 exp = auth_authenticate_internal(what, caller, epath,
 172                                                  &hp, &error);
 173                 if (exp || (error != not_exported && error != no_entry))
 174                         break;
 175                 /* We have to treat the root, "/", specially. */
 176                 if (p == &epath[1]) break;
 177                 p = strrchr(epath, '/');
 178                 if (p == epath) p++;
 179                 *p = '\0';
 180         }
 181
 182         switch (error) {
 183         case bad_path:
 184                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 185                      what, inet_ntoa(addr), path);
 186                 break;
 187
 188         case unknown_host:
 189                 xlog(L_WARNING, "%s request from unknown host %s for %s (%s)",
 190                      what, inet_ntoa(addr), path, epath);
 191                 break;
 192
 193         case no_entry:
 194                 xlog(L_WARNING, "refused %s request from %s for %s (%s): no export entry",
 195                      what, hp->h_name, path, epath);
 196                 break;
 197
 198         case not_exported:
 199                 xlog(L_WARNING, "refused %s request from %s for %s (%s): not exported",
 200                      what, hp->h_name, path, epath);
 201                 break;
 202
 203         case illegal_port:
 204                 xlog(L_WARNING, "refused %s request from %s for %s (%s): illegal port %d",
 205                      what, hp->h_name, path, epath, ntohs(caller->sin_port));
 206                 break;
 207
 208         case faked_hostent:
 209                 xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): DNS forward lookup does't match with reverse",
 210                      what, inet_ntoa(addr), hp->h_name, path, epath);
 211                 break;
 212
 213         case no_forward_dns:
 214                 xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): no DNS forward lookup",
 215                      what, inet_ntoa(addr), hp->h_name, path, epath);
 216                 break;
 217
 218         case success:
 219                 xlog(L_NOTICE, "authenticated %s request from %s:%d for %s (%s)",
 220                      what, hp->h_name, ntohs(caller->sin_port), path, epath);
 221                 break;
 222         default:
 223                 xlog(L_NOTICE, "%s request from %s:%d for %s (%s) gave %d",
 224                      what, hp->h_name, ntohs(caller->sin_port), path, epath, error);
 225         }
 226
 227         if (hp)
 228                 free (hp);
 229
 230         return exp;
 231 }
 232
 233 static void
 234 auth_fixpath(char *path)
 235 {
 236         char    *sp, *cp;
 237
 238         for (sp = cp = path; *sp; sp++) {
 239                 if (*sp != '/' || sp[1] != '/')
 240                         *cp++ = *sp;
 241         }
 242         while (cp > path+1 && cp[-1] == '/')
 243                 cp--;
 244         *cp = '\0';
 245 }