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   DIAG_PUSH_NEEDS_COMMENT;
  56   DIAG_IGNORE_NEEDS_COMMENT (8, "-Wformat-overflow");
  57   sprintf (netname, "%s.%d@%s", OPSYS, uid, dfltdom);
  58   DIAG_POP_NEEDS_COMMENT;
  59   i = strlen (netname);
  60   if (netname[i - 1] == '.')
  61     netname[i - 1] = '\0';
  62   return 1;
  63 }
  64 libc_hidden_nolink_sunrpc (user2netname, GLIBC_2_1)
  65
  66 int
  67 host2netname (char netname[MAXNETNAMELEN + 1], const char *host,
  68               const char *domain)
  69 {
  70   char *p;
  71   char hostname[MAXHOSTNAMELEN + 1];
  72   char domainname[MAXHOSTNAMELEN + 1];
  73   char *dot_in_host;
  74   size_t i;
  75
  76   netname[0] = '\0';            /* make null first (no need for memset) */
  77
  78   if (host == NULL)
  79     __gethostname (hostname, MAXHOSTNAMELEN);
  80   else
  81     {
  82       strncpy (hostname, host, MAXHOSTNAMELEN);
  83       hostname[MAXHOSTNAMELEN] = '\0';
  84     }
  85
  86   dot_in_host = strchr (hostname, '.');
  87   if (domain == NULL)
  88     {
  89       p = dot_in_host;
  90       if (p)
  91         {
  92           ++p;
  93           strncpy (domainname, p, MAXHOSTNAMELEN);
  94           domainname[MAXHOSTNAMELEN] = '\0';
  95         }
  96       else
  97         {
  98           domainname[0] = 0;
  99           if (getdomainname (domainname, MAXHOSTNAMELEN))
 100             return 0;
 101         }
 102     }
 103   else
 104     {
 105       strncpy (domainname, domain, MAXHOSTNAMELEN);
 106       domainname[MAXHOSTNAMELEN] = '\0';
 107     }
 108
 109   i = strlen (domainname);
 110   if (i == 0)
 111     /* No domainname */
 112     return 0;
 113   if (domainname[i - 1] == '.')
 114     domainname[i - 1] = 0;
 115
 116   if (dot_in_host)              /* strip off rest of name */
 117     *dot_in_host = '\0';
 118
 119   if ((strlen (domainname) + strlen (hostname) + OPSYS_LEN + 3)
 120       > MAXNETNAMELEN)
 121     return 0;
 122
 123   sprintf (netname, "%s.%s@%s", OPSYS, hostname, domainname);
 124   return 1;
 125 }
 126 #ifdef EXPORT_RPC_SYMBOLS
 127 libc_hidden_def (host2netname)
 128 #else
 129 libc_hidden_nolink_sunrpc (host2netname, GLIBC_2_1)
 130 #endif
 131
 132 int
 133 getnetname (char name[MAXNETNAMELEN + 1])
 134 {
 135   uid_t uid;
 136   int dummy;
 137
 138   uid = __geteuid ();
 139   if (uid == 0)
 140     dummy = host2netname (name, NULL, NULL);
 141   else
 142     dummy = user2netname (name, uid, NULL);
 143   return (dummy);
 144 }
 145 libc_hidden_nolink_sunrpc (getnetname, GLIBC_2_1)
 146
 147 /* Type of the lookup function for netname2user.  */
 148 typedef int (*netname2user_function) (const char netname[MAXNETNAMELEN + 1],
 149                                       uid_t *, gid_t *, int *, gid_t *);
 150
 151 int
 152 netname2user (const char *netname, uid_t * uidp, gid_t * gidp,
 153               int *gidlenp, gid_t * gidlist)
 154 {
 155   nss_action_list nip;
 156   union
 157   {
 158     netname2user_function f;
 159     void *ptr;
 160   } fct;
 161   enum nss_status status = NSS_STATUS_UNAVAIL;
 162   int no_more;
 163
 164   no_more = __nss_publickey_lookup2 (&nip, "netname2user", NULL, &fct.ptr);
 165
 166   while (!no_more)
 167     {
 168       status = (*fct.f) (netname, uidp, gidp, gidlenp, gidlist);
 169
 170       no_more = __nss_next2 (&nip, "netname2user", NULL, &fct.ptr, status, 0);
 171     }
 172
 173   return status == NSS_STATUS_SUCCESS;
 174 }
 175 #ifdef EXPORT_RPC_SYMBOLS
 176 libc_hidden_def (netname2user)
 177 #else
 178 libc_hidden_nolink_sunrpc (netname2user, GLIBC_2_1)
 179 #endif
 180
 181 int
 182 netname2host (const char *netname, char *hostname, const int hostlen)
 183 {
 184   char *p1, *p2;
 185
 186   p1 = strchr (netname, '.');
 187   if (p1 == NULL)
 188     return 0;
 189   p1++;
 190
 191   p2 = strchr (p1, '@');
 192   if (p2 == NULL)
 193     return 0;
 194   *p2 = '\0';
 195
 196   if (hostlen > MAXNETNAMELEN)
 197     return 0;
 198
 199   strncpy (hostname, p1, hostlen);
 200   hostname[hostlen] = '\0';
 201
 202   return 1;
 203 }
 204 libc_hidden_nolink_sunrpc (netname2host, GLIBC_2_1)