sunrpc/netname.c

   1 /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <stdio.h>
  19 #include <unistd.h>
  20 #include <string.h>
  21 #include <rpc/rpc.h>
  22 #include <shlib-compat.h>
  23 #include <libc-diag.h>
  24
  25 #include "nsswitch.h"
  26
  27 #define OPSYS_LEN 4
  28 #define MAXIPRINT (11)          /* max length of printed integer */
  29 static const char OPSYS[] = "unix";
  30
  31 int
  32 user2netname (char netname[MAXNETNAMELEN + 1], const uid_t uid,
  33               const char *domain)
  34 {
  35   char dfltdom[MAXNETNAMELEN + 1];
  36   size_t i;
  37
  38   if (domain == NULL)
  39     {
  40       if (getdomainname (dfltdom, sizeof (dfltdom)) < 0)
  41         return 0;
  42     }
  43   else
  44     {
  45       strncpy (dfltdom, domain, MAXNETNAMELEN);
  46       dfltdom[MAXNETNAMELEN] = '\0';
  47     }
  48
  49   if ((strlen (dfltdom) + OPSYS_LEN + 3 + MAXIPRINT) > (size_t) MAXNETNAMELEN)
  50     return 0;
  51
  52   /* GCC with -Os or -O1 warns that sprint might overflow while handling
  53      dfltdom, however the above test does check if an overflow would
  54      happen.  */
  55 #if __GNUC_PREREQ (8, 0)
  56   DIAG_PUSH_NEEDS_COMMENT;
  57   DIAG_IGNORE_NEEDS_COMMENT (8, "-Wformat-overflow");
  58 #endif
  59   sprintf (netname, "%s.%d@%s", OPSYS, uid, dfltdom);
  60 #if __GNUC_PREREQ (8, 0)
  61   DIAG_POP_NEEDS_COMMENT;
  62 #endif
  63   i = strlen (netname);
  64   if (netname[i - 1] == '.')
  65     netname[i - 1] = '\0';
  66   return 1;
  67 }
  68 libc_hidden_nolink_sunrpc (user2netname, GLIBC_2_1)
  69
  70 int
  71 host2netname (char netname[MAXNETNAMELEN + 1], const char *host,
  72               const char *domain)
  73 {
  74   char *p;
  75   char hostname[MAXHOSTNAMELEN + 1];
  76   char domainname[MAXHOSTNAMELEN + 1];
  77   char *dot_in_host;
  78   size_t i;
  79
  80   netname[0] = '\0';            /* make null first (no need for memset) */
  81
  82   if (host == NULL)
  83     __gethostname (hostname, MAXHOSTNAMELEN);
  84   else
  85     {
  86       strncpy (hostname, host, MAXHOSTNAMELEN);
  87       hostname[MAXHOSTNAMELEN] = '\0';
  88     }
  89
  90   dot_in_host = strchr (hostname, '.');
  91   if (domain == NULL)
  92     {
  93       p = dot_in_host;
  94       if (p)
  95         {
  96           ++p;
  97           strncpy (domainname, p, MAXHOSTNAMELEN);
  98           domainname[MAXHOSTNAMELEN] = '\0';
  99         }
 100       else
 101         {
 102           domainname[0] = 0;
 103           if (getdomainname (domainname, MAXHOSTNAMELEN))
 104             return 0;
 105         }
 106     }
 107   else
 108     {
 109       strncpy (domainname, domain, MAXHOSTNAMELEN);
 110       domainname[MAXHOSTNAMELEN] = '\0';
 111     }
 112
 113   i = strlen (domainname);
 114   if (i == 0)
 115     /* No domainname */
 116     return 0;
 117   if (domainname[i - 1] == '.')
 118     domainname[i - 1] = 0;
 119
 120   if (dot_in_host)              /* strip off rest of name */
 121     *dot_in_host = '\0';
 122
 123   if ((strlen (domainname) + strlen (hostname) + OPSYS_LEN + 3)
 124       > MAXNETNAMELEN)
 125     return 0;
 126
 127   sprintf (netname, "%s.%s@%s", OPSYS, hostname, domainname);
 128   return 1;
 129 }
 130 #ifdef EXPORT_RPC_SYMBOLS
 131 libc_hidden_def (host2netname)
 132 #else
 133 libc_hidden_nolink_sunrpc (host2netname, GLIBC_2_1)
 134 #endif
 135
 136 int
 137 getnetname (char name[MAXNETNAMELEN + 1])
 138 {
 139   uid_t uid;
 140   int dummy;
 141
 142   uid = __geteuid ();
 143   if (uid == 0)
 144     dummy = host2netname (name, NULL, NULL);
 145   else
 146     dummy = user2netname (name, uid, NULL);
 147   return (dummy);
 148 }
 149 libc_hidden_nolink_sunrpc (getnetname, GLIBC_2_1)
 150
 151 /* Type of the lookup function for netname2user.  */
 152 typedef int (*netname2user_function) (const char netname[MAXNETNAMELEN + 1],
 153                                       uid_t *, gid_t *, int *, gid_t *);
 154
 155 int
 156 netname2user (const char *netname, uid_t * uidp, gid_t * gidp,
 157               int *gidlenp, gid_t * gidlist)
 158 {
 159   nss_action_list nip;
 160   union
 161   {
 162     netname2user_function f;
 163     void *ptr;
 164   } fct;
 165   enum nss_status status = NSS_STATUS_UNAVAIL;
 166   int no_more;
 167
 168   no_more = __nss_publickey_lookup2 (&nip, "netname2user", NULL, &fct.ptr);
 169
 170   while (!no_more)
 171     {
 172       status = (*fct.f) (netname, uidp, gidp, gidlenp, gidlist);
 173
 174       no_more = __nss_next2 (&nip, "netname2user", NULL, &fct.ptr, status, 0);
 175     }
 176
 177   return status == NSS_STATUS_SUCCESS;
 178 }
 179 #ifdef EXPORT_RPC_SYMBOLS
 180 libc_hidden_def (netname2user)
 181 #else
 182 libc_hidden_nolink_sunrpc (netname2user, GLIBC_2_1)
 183 #endif
 184
 185 int
 186 netname2host (const char *netname, char *hostname, const int hostlen)
 187 {
 188   char *p1, *p2;
 189
 190   p1 = strchr (netname, '.');
 191   if (p1 == NULL)
 192     return 0;
 193   p1++;
 194
 195   p2 = strchr (p1, '@');
 196   if (p2 == NULL)
 197     return 0;
 198   *p2 = '\0';
 199
 200   if (hostlen > MAXNETNAMELEN)
 201     return 0;
 202
 203   strncpy (hostname, p1, hostlen);
 204   hostname[hostlen] = '\0';
 205
 206   return 1;
 207 }
 208 libc_hidden_nolink_sunrpc (netname2host, GLIBC_2_1)