glibc/sunrpc/netname.c

/* Copyright (C) 1997-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <rpc/rpc.h>
#include <shlib-compat.h>
#include <libc-diag.h>

#include "nsswitch.h"

#define	OPSYS_LEN 4
#define	MAXIPRINT (11)		/* max length of printed integer */
static const char OPSYS[] = "unix";

int
user2netname (char netname[MAXNETNAMELEN + 1], const uid_t uid,
	      const char *domain)
{
  char dfltdom[MAXNETNAMELEN + 1];
  size_t i;

  if (domain == NULL)
    {
      if (getdomainname (dfltdom, sizeof (dfltdom)) < 0)
	return 0;
    }
  else
    {
      strncpy (dfltdom, domain, MAXNETNAMELEN);
      dfltdom[MAXNETNAMELEN] = '\0';
    }

  if ((strlen (dfltdom) + OPSYS_LEN + 3 + MAXIPRINT) > (size_t) MAXNETNAMELEN)
    return 0;

  /* GCC with -Os or -O1 warns that sprint might overflow while handling
     dfltdom, however the above test does check if an overflow would
     happen.  */
#if __GNUC_PREREQ (8, 0)
  DIAG_PUSH_NEEDS_COMMENT;
  DIAG_IGNORE_NEEDS_COMMENT (8, "-Wformat-overflow");
#endif
  sprintf (netname, "%s.%d@%s", OPSYS, uid, dfltdom);
#if __GNUC_PREREQ (8, 0)
  DIAG_POP_NEEDS_COMMENT;
#endif
  i = strlen (netname);
  if (netname[i - 1] == '.')
    netname[i - 1] = '\0';
  return 1;
}
libc_hidden_nolink_sunrpc (user2netname, GLIBC_2_1)

int
host2netname (char netname[MAXNETNAMELEN + 1], const char *host,
	      const char *domain)
{
  char *p;
  char hostname[MAXHOSTNAMELEN + 1];
  char domainname[MAXHOSTNAMELEN + 1];
  char *dot_in_host;
  size_t i;

  netname[0] = '\0';		/* make null first (no need for memset) */

  if (host == NULL)
    __gethostname (hostname, MAXHOSTNAMELEN);
  else
    {
      strncpy (hostname, host, MAXHOSTNAMELEN);
      hostname[MAXHOSTNAMELEN] = '\0';
    }

  dot_in_host = strchr (hostname, '.');
  if (domain == NULL)
    {
      p = dot_in_host;
      if (p)
	{
	  ++p;
	  strncpy (domainname, p, MAXHOSTNAMELEN);
	  domainname[MAXHOSTNAMELEN] = '\0';
	}
      else
	{
	  domainname[0] = 0;
	  if (getdomainname (domainname, MAXHOSTNAMELEN))
	    return 0;
	}
    }
  else
    {
      strncpy (domainname, domain, MAXHOSTNAMELEN);
      domainname[MAXHOSTNAMELEN] = '\0';
    }

  i = strlen (domainname);
  if (i == 0)
    /* No domainname */
    return 0;
  if (domainname[i - 1] == '.')
    domainname[i - 1] = 0;

  if (dot_in_host)		/* strip off rest of name */
    *dot_in_host = '\0';

  if ((strlen (domainname) + strlen (hostname) + OPSYS_LEN + 3)
      > MAXNETNAMELEN)
    return 0;

  sprintf (netname, "%s.%s@%s", OPSYS, hostname, domainname);
  return 1;
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (host2netname)
#else
libc_hidden_nolink_sunrpc (host2netname, GLIBC_2_1)
#endif

int
getnetname (char name[MAXNETNAMELEN + 1])
{
  uid_t uid;
  int dummy;

  uid = __geteuid ();
  if (uid == 0)
    dummy = host2netname (name, NULL, NULL);
  else
    dummy = user2netname (name, uid, NULL);
  return (dummy);
}
libc_hidden_nolink_sunrpc (getnetname, GLIBC_2_1)

/* Type of the lookup function for netname2user.  */
typedef int (*netname2user_function) (const char netname[MAXNETNAMELEN + 1],
				      uid_t *, gid_t *, int *, gid_t *);

int
netname2user (const char *netname, uid_t * uidp, gid_t * gidp,
	      int *gidlenp, gid_t * gidlist)
{
  nss_action_list nip;
  union
  {
    netname2user_function f;
    void *ptr;
  } fct;
  enum nss_status status = NSS_STATUS_UNAVAIL;
  int no_more;

  no_more = __nss_publickey_lookup2 (&nip, "netname2user", NULL, &fct.ptr);

  while (!no_more)
    {
      status = (*fct.f) (netname, uidp, gidp, gidlenp, gidlist);

      no_more = __nss_next2 (&nip, "netname2user", NULL, &fct.ptr, status, 0);
    }

  return status == NSS_STATUS_SUCCESS;
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (netname2user)
#else
libc_hidden_nolink_sunrpc (netname2user, GLIBC_2_1)
#endif

int
netname2host (const char *netname, char *hostname, const int hostlen)
{
  char *p1, *p2;

  p1 = strchr (netname, '.');
  if (p1 == NULL)
    return 0;
  p1++;

  p2 = strchr (p1, '@');
  if (p2 == NULL)
    return 0;
  *p2 = '\0';

  if (hostlen > MAXNETNAMELEN)
    return 0;

  strncpy (hostname, p1, hostlen);
  hostname[hostlen] = '\0';

  return 1;
}
libc_hidden_nolink_sunrpc (netname2host, GLIBC_2_1)