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         if (!(*hpp = gethostbyaddr((const char *)&addr, sizeof(addr), AF_INET)))
  82                 *hpp = get_hostent((const char *)&addr, sizeof(addr),
  83                                    AF_INET);
  84         else {
  85                 /* must make sure the hostent is authorative. */
  86                 char **sp;
  87                 struct hostent *forward = NULL;
  88                 char *tmpname;
  89
  90                 tmpname = xstrdup((*hpp)->h_name);
  91                 if (tmpname) {
  92                         forward = gethostbyname(tmpname);
  93                         free(tmpname);
  94                 }
  95                 if (forward) {
  96                         /* now make sure the "addr" is in the list */
  97                         for (sp = forward->h_addr_list ; *sp ; sp++) {
  98                                 if (memcmp(*sp, &addr, forward->h_length)==0)
  99                                         break;
 100                         }
 101
 102                         if (!*sp) {
 103                                 /* it was a FAKE */
 104                                 *error = faked_hostent;
 105                                 *hpp = hostent_dup (*hpp);
 106                                 return NULL;
 107                         }
 108                         *hpp = hostent_dup (forward);
 109                 }
 110                 else {
 111                         /* never heard of it. misconfigured DNS? */
 112                         *error = no_forward_dns;
 113                         *hpp = hostent_dup (*hpp);
 114                         return NULL;
 115                 }
 116         }
 117
 118         if (!(exp = export_find(*hpp, path))) {
 119                 *error = no_entry;
 120                 return NULL;
 121         }
 122         if (!exp->m_mayexport) {
 123                 *error = not_exported;
 124                 return NULL;
 125         }
 126
 127         if (!(exp->m_export.e_flags & NFSEXP_INSECURE_PORT) &&
 128             (ntohs(caller->sin_port) <  IPPORT_RESERVED/2 ||
 129              ntohs(caller->sin_port) >= IPPORT_RESERVED)) {
 130                 *error = illegal_port;
 131                 return NULL;
 132         }
 133
 134         *error = success;
 135
 136         return exp;
 137 }
 138
 139 nfs_export *
 140 auth_authenticate(char *what, struct sockaddr_in *caller, char *path)
 141 {
 142         nfs_export      *exp = NULL;
 143         char            epath[MAXPATHLEN+1];
 144         char            *p = NULL;
 145         struct hostent  *hp = NULL;
 146         struct in_addr  addr = caller->sin_addr;
 147         enum auth_error error;
 148
 149         if (path [0] != '/') return exp;
 150
 151         strncpy(epath, path, sizeof (epath) - 1);
 152         epath[sizeof (epath) - 1] = '\0';
 153
 154         /* Try the longest matching exported pathname. */
 155         while (1) {
 156                 if (hp) {
 157                         free (hp);
 158                         hp = NULL;
 159                 }
 160                 exp = auth_authenticate_internal(what, caller, epath,
 161                                                  &hp, &error);
 162                 if (exp || (error != not_exported && error != no_entry))
 163                         break;
 164                 /* We have to treat the root, "/", specially. */
 165                 if (p == &epath[1]) break;
 166                 p = strrchr(epath, '/');
 167                 if (p == epath) p++;
 168                 *p = '\0';
 169         }
 170
 171         switch (error) {
 172         case bad_path:
 173                 xlog(L_WARNING, "bad path in %s request from %s: \"%s\"",
 174                      what, inet_ntoa(addr), path);
 175                 break;
 176
 177         case unknown_host:
 178                 xlog(L_WARNING, "%s request from unknown host %s for %s (%s)",
 179                      what, inet_ntoa(addr), path, epath);
 180                 break;
 181
 182         case no_entry:
 183                 xlog(L_WARNING, "refused %s request from %s for %s (%s): no export entry",
 184                      what, hp->h_name, path, epath);
 185                 break;
 186
 187         case not_exported:
 188                 xlog(L_WARNING, "refused %s request from %s for %s (%s): not exported",
 189                      what, hp->h_name, path, epath);
 190                 break;
 191
 192         case illegal_port:
 193                 xlog(L_WARNING, "refused %s request from %s for %s (%s): illegal port %d",
 194                      what, hp->h_name, path, epath, ntohs(caller->sin_port));
 195                 break;
 196
 197         case faked_hostent:
 198                 xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): DNS forward lookup does't match with reverse",
 199                      what, inet_ntoa(addr), hp->h_name, path, epath);
 200                 break;
 201
 202         case no_forward_dns:
 203                 xlog(L_WARNING, "refused %s request from %s (%s) for %s (%s): no DNS forward lookup",
 204                      what, inet_ntoa(addr), hp->h_name, path, epath);
 205                 break;
 206
 207         case success:
 208                 xlog(L_NOTICE, "authenticated %s request from %s:%d for %s (%s)",
 209                      what, hp->h_name, ntohs(caller->sin_port), path, epath);
 210                 break;
 211         default:
 212                 xlog(L_NOTICE, "%s request from %s:%d for %s (%s) gave %d",
 213                      what, hp->h_name, ntohs(caller->sin_port), path, epath, error);
 214         }
 215
 216         if (hp)
 217                 free (hp);
 218
 219         return exp;
 220 }
 221
 222 static void
 223 auth_fixpath(char *path)
 224 {
 225         char    *sp, *cp;
 226
 227         for (sp = cp = path; *sp; sp++) {
 228                 if (*sp != '/' || sp[1] != '/')
 229                         *cp++ = *sp;
 230         }
 231         while (cp > path+1 && cp[-1] == '/')
 232                 cp--;
 233         *cp = '\0';
 234 }