sunrpc/netname.c

   1 /* Copyright (C) 1997-2022 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 warns that sprint might overflow while handling dfltdom,
  53      however the above test does check if an overflow would happen.  */
  54   DIAG_PUSH_NEEDS_COMMENT;
  55   DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wformat-overflow");
  56   sprintf (netname, "%s.%d@%s", OPSYS, uid, dfltdom);
  57   DIAG_POP_NEEDS_COMMENT;
  58   i = strlen (netname);
  59   if (netname[i - 1] == '.')
  60     netname[i - 1] = '\0';
  61   return 1;
  62 }
  63 libc_hidden_nolink_sunrpc (user2netname, GLIBC_2_1)
  64
  65 int
  66 host2netname (char netname[MAXNETNAMELEN + 1], const char *host,
  67               const char *domain)
  68 {
  69   char *p;
  70   char hostname[MAXHOSTNAMELEN + 1];
  71   char domainname[MAXHOSTNAMELEN + 1];
  72   char *dot_in_host;
  73   size_t i;
  74
  75   netname[0] = '\0';            /* make null first (no need for memset) */
  76
  77   if (host == NULL)
  78     __gethostname (hostname, MAXHOSTNAMELEN);
  79   else
  80     {
  81       strncpy (hostname, host, MAXHOSTNAMELEN);
  82       hostname[MAXHOSTNAMELEN] = '\0';
  83     }
  84
  85   dot_in_host = strchr (hostname, '.');
  86   if (domain == NULL)
  87     {
  88       p = dot_in_host;
  89       if (p)
  90         {
  91           ++p;
  92           strncpy (domainname, p, MAXHOSTNAMELEN);
  93           domainname[MAXHOSTNAMELEN] = '\0';
  94         }
  95       else
  96         {
  97           domainname[0] = 0;
  98           getdomainname (domainname, MAXHOSTNAMELEN);
  99         }
 100     }
 101   else
 102     {
 103       strncpy (domainname, domain, MAXHOSTNAMELEN);
 104       domainname[MAXHOSTNAMELEN] = '\0';
 105     }
 106
 107   i = strlen (domainname);
 108   if (i == 0)
 109     /* No domainname */
 110     return 0;
 111   if (domainname[i - 1] == '.')
 112     domainname[i - 1] = 0;
 113
 114   if (dot_in_host)              /* strip off rest of name */
 115     *dot_in_host = '\0';
 116
 117   if ((strlen (domainname) + strlen (hostname) + OPSYS_LEN + 3)
 118       > MAXNETNAMELEN)
 119     return 0;
 120
 121   sprintf (netname, "%s.%s@%s", OPSYS, hostname, domainname);
 122   return 1;
 123 }
 124 #ifdef EXPORT_RPC_SYMBOLS
 125 libc_hidden_def (host2netname)
 126 #else
 127 libc_hidden_nolink_sunrpc (host2netname, GLIBC_2_1)
 128 #endif
 129
 130 int
 131 getnetname (char name[MAXNETNAMELEN + 1])
 132 {
 133   uid_t uid;
 134   int dummy;
 135
 136   uid = __geteuid ();
 137   if (uid == 0)
 138     dummy = host2netname (name, NULL, NULL);
 139   else
 140     dummy = user2netname (name, uid, NULL);
 141   return (dummy);
 142 }
 143 libc_hidden_nolink_sunrpc (getnetname, GLIBC_2_1)
 144
 145 /* Type of the lookup function for netname2user.  */
 146 typedef int (*netname2user_function) (const char netname[MAXNETNAMELEN + 1],
 147                                       uid_t *, gid_t *, int *, gid_t *);
 148
 149 int
 150 netname2user (const char *netname, uid_t * uidp, gid_t * gidp,
 151               int *gidlenp, gid_t * gidlist)
 152 {
 153   nss_action_list nip;
 154   union
 155   {
 156     netname2user_function f;
 157     void *ptr;
 158   } fct;
 159   enum nss_status status = NSS_STATUS_UNAVAIL;
 160   int no_more;
 161
 162   no_more = __nss_publickey_lookup2 (&nip, "netname2user", NULL, &fct.ptr);
 163
 164   while (!no_more)
 165     {
 166       status = (*fct.f) (netname, uidp, gidp, gidlenp, gidlist);
 167
 168       no_more = __nss_next2 (&nip, "netname2user", NULL, &fct.ptr, status, 0);
 169     }
 170
 171   return status == NSS_STATUS_SUCCESS;
 172 }
 173 #ifdef EXPORT_RPC_SYMBOLS
 174 libc_hidden_def (netname2user)
 175 #else
 176 libc_hidden_nolink_sunrpc (netname2user, GLIBC_2_1)
 177 #endif
 178
 179 int
 180 netname2host (const char *netname, char *hostname, const int hostlen)
 181 {
 182   char *p1, *p2;
 183
 184   p1 = strchr (netname, '.');
 185   if (p1 == NULL)
 186     return 0;
 187   p1++;
 188
 189   p2 = strchr (p1, '@');
 190   if (p2 == NULL)
 191     return 0;
 192   *p2 = '\0';
 193
 194   if (hostlen > MAXNETNAMELEN)
 195     return 0;
 196
 197   strncpy (hostname, p1, hostlen);
 198   hostname[hostlen] = '\0';
 199
 200   return 1;
 201 }
 202 libc_hidden_nolink_sunrpc (netname2host, GLIBC_2_1)