642 lines
16 KiB
C
642 lines
16 KiB
C
/* Inner loops of cache daemon.
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Copyright (C) 1998,1999,2000,2001,2002,2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <error.h>
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#include <errno.h>
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#include <grp.h>
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#include <pthread.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <libintl.h>
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#include <arpa/inet.h>
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#include <sys/param.h>
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#include <sys/poll.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/un.h>
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#include "nscd.h"
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#include "dbg_log.h"
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/* Wrapper functions with error checking for standard functions. */
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extern void *xmalloc (size_t n);
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extern void *xcalloc (size_t n, size_t s);
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extern void *xrealloc (void *o, size_t n);
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/* Support to run nscd as an unprivileged user */
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const char *server_user;
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static uid_t server_uid;
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static gid_t server_gid;
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static gid_t *server_groups;
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#ifndef NGROUPS
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# define NGROUPS 32
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#endif
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static int server_ngroups = NGROUPS;
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static void begin_drop_privileges (void);
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static void finish_drop_privileges (void);
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/* Mapping of request type to database. */
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static const dbtype serv2db[LASTDBREQ + 1] =
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{
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[GETPWBYNAME] = pwddb,
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[GETPWBYUID] = pwddb,
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[GETGRBYNAME] = grpdb,
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[GETGRBYGID] = grpdb,
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[GETHOSTBYNAME] = hstdb,
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[GETHOSTBYNAMEv6] = hstdb,
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[GETHOSTBYADDR] = hstdb,
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[GETHOSTBYADDRv6] = hstdb,
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};
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/* Map request type to a string. */
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const char *serv2str[LASTREQ] =
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{
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[GETPWBYNAME] = "GETPWBYNAME",
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[GETPWBYUID] = "GETPWBYUID",
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[GETGRBYNAME] = "GETGRBYNAME",
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[GETGRBYGID] = "GETGRBYGID",
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[GETHOSTBYNAME] = "GETHOSTBYNAME",
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[GETHOSTBYNAMEv6] = "GETHOSTBYNAMEv6",
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[GETHOSTBYADDR] = "GETHOSTBYADDR",
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[GETHOSTBYADDRv6] = "GETHOSTBYADDRv6",
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[SHUTDOWN] = "SHUTDOWN",
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[GETSTAT] = "GETSTAT",
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[INVALIDATE] = "INVALIDATE"
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};
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/* The control data structures for the services. */
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static struct database dbs[lastdb] =
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{
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[pwddb] = {
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.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
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.enabled = 0,
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.check_file = 1,
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.filename = "/etc/passwd",
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.module = 211,
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.disabled_iov = &pwd_iov_disabled,
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.postimeout = 3600,
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.negtimeout = 20
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},
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[grpdb] = {
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.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
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.enabled = 0,
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.check_file = 1,
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.filename = "/etc/group",
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.module = 211,
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.disabled_iov = &grp_iov_disabled,
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.postimeout = 3600,
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.negtimeout = 60
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},
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[hstdb] = {
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.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
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.enabled = 0,
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.check_file = 1,
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.filename = "/etc/hosts",
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.module = 211,
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.disabled_iov = &hst_iov_disabled,
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.postimeout = 3600,
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.negtimeout = 20
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}
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};
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/* Number of seconds between two cache pruning runs. */
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#define CACHE_PRUNE_INTERVAL 15
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/* Number of threads to use. */
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int nthreads = -1;
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/* Socket for incoming connections. */
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static int sock;
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/* Initialize database information structures. */
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void
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nscd_init (const char *conffile)
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{
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struct sockaddr_un sock_addr;
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size_t cnt;
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/* Read the configuration file. */
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if (nscd_parse_file (conffile, dbs) != 0)
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{
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/* We couldn't read the configuration file. Disable all services
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by shutting down the srever. */
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dbg_log (_("cannot read configuration file; this is fatal"));
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exit (1);
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}
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/* Secure mode and unprivileged mode are incompatible */
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if (server_user != NULL && secure_in_use)
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{
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dbg_log (_("Cannot run nscd in secure mode as unprivileged user"));
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exit (1);
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}
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/* Look up unprivileged uid/gid/groups before we start listening on the
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socket */
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if (server_user != NULL)
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begin_drop_privileges ();
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if (nthreads == -1)
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/* No configuration for this value, assume a default. */
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nthreads = 2 * lastdb;
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for (cnt = 0; cnt < lastdb; ++cnt)
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if (dbs[cnt].enabled)
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{
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pthread_rwlock_init (&dbs[cnt].lock, NULL);
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dbs[cnt].array = (struct hashentry **)
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calloc (dbs[cnt].module, sizeof (struct hashentry *));
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if (dbs[cnt].array == NULL)
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{
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dbg_log (_("while allocating cache: %s"), strerror (errno));
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exit (1);
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}
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if (dbs[cnt].check_file)
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{
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/* We need the modification date of the file. */
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struct stat st;
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if (stat (dbs[cnt].filename, &st) < 0)
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{
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/* We cannot stat() the file, disable file checking. */
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dbg_log (_("cannot stat() file `%s': %s"),
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dbs[cnt].filename, strerror (errno));
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dbs[cnt].check_file = 0;
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}
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else
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dbs[cnt].file_mtime = st.st_mtime;
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}
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}
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/* Create the socket. */
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sock = socket (AF_UNIX, SOCK_STREAM, 0);
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if (sock < 0)
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{
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dbg_log (_("cannot open socket: %s"), strerror (errno));
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exit (1);
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}
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/* Bind a name to the socket. */
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sock_addr.sun_family = AF_UNIX;
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strcpy (sock_addr.sun_path, _PATH_NSCDSOCKET);
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if (bind (sock, (struct sockaddr *) &sock_addr, sizeof (sock_addr)) < 0)
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{
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dbg_log ("%s: %s", _PATH_NSCDSOCKET, strerror (errno));
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exit (1);
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}
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/* Set permissions for the socket. */
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chmod (_PATH_NSCDSOCKET, 0666);
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/* Set the socket up to accept connections. */
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if (listen (sock, SOMAXCONN) < 0)
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{
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dbg_log (_("cannot enable socket to accept connections: %s"),
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strerror (errno));
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exit (1);
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}
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/* Change to unprivileged uid/gid/groups if specifed in config file */
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if (server_user != NULL)
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finish_drop_privileges ();
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}
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/* Close the connections. */
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void
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close_sockets (void)
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{
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close (sock);
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}
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static void
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invalidate_cache (char *key)
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{
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dbtype number;
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if (strcmp (key, "passwd") == 0)
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number = pwddb;
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else if (strcmp (key, "group") == 0)
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number = grpdb;
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else if (__builtin_expect (strcmp (key, "hosts"), 0) == 0)
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number = hstdb;
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else
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return;
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if (dbs[number].enabled)
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prune_cache (&dbs[number], LONG_MAX);
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}
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/* Handle new request. */
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static void
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handle_request (int fd, request_header *req, void *key, uid_t uid)
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{
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if (__builtin_expect (debug_level, 0) > 0)
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dbg_log (_("handle_request: request received (Version = %d)"),
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req->version);
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if (__builtin_expect (req->version, NSCD_VERSION) != NSCD_VERSION)
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{
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if (debug_level > 0)
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dbg_log (_("\
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cannot handle old request version %d; current version is %d"),
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req->version, NSCD_VERSION);
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return;
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}
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if (__builtin_expect (req->type, GETPWBYNAME) >= GETPWBYNAME
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&& __builtin_expect (req->type, LASTDBREQ) <= LASTDBREQ)
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{
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struct hashentry *cached;
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struct database *db = &dbs[serv2db[req->type]];
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if (__builtin_expect (debug_level, 0) > 0)
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{
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if (req->type == GETHOSTBYADDR || req->type == GETHOSTBYADDRv6)
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{
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char buf[INET6_ADDRSTRLEN];
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dbg_log ("\t%s (%s)", serv2str[req->type],
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inet_ntop (req->type == GETHOSTBYADDR
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? AF_INET : AF_INET6,
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key, buf, sizeof (buf)));
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}
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else
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dbg_log ("\t%s (%s)", serv2str[req->type], (char *)key);
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}
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/* Is this service enabled? */
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if (!db->enabled)
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{
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/* No, sent the prepared record. */
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if (TEMP_FAILURE_RETRY (write (fd, db->disabled_iov->iov_base,
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db->disabled_iov->iov_len))
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!= (ssize_t) db->disabled_iov->iov_len
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&& __builtin_expect (debug_level, 0) > 0)
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{
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/* We have problems sending the result. */
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char buf[256];
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dbg_log (_("cannot write result: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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}
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return;
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}
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/* Be sure we can read the data. */
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pthread_rwlock_rdlock (&db->lock);
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/* See whether we can handle it from the cache. */
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cached = (struct hashentry *) cache_search (req->type, key, req->key_len,
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db, uid);
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if (cached != NULL)
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{
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/* Hurray it's in the cache. */
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if (TEMP_FAILURE_RETRY (write (fd, cached->packet, cached->total))
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!= cached->total
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&& __builtin_expect (debug_level, 0) > 0)
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{
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/* We have problems sending the result. */
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char buf[256];
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dbg_log (_("cannot write result: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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}
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pthread_rwlock_unlock (&db->lock);
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return;
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}
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pthread_rwlock_unlock (&db->lock);
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}
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else if (__builtin_expect (debug_level, 0) > 0)
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{
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if (req->type == INVALIDATE)
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dbg_log ("\t%s (%s)", serv2str[req->type], (char *)key);
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else
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dbg_log ("\t%s", serv2str[req->type]);
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}
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/* Handle the request. */
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switch (req->type)
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{
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case GETPWBYNAME:
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addpwbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETPWBYUID:
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addpwbyuid (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETGRBYNAME:
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addgrbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETGRBYGID:
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addgrbygid (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETHOSTBYNAME:
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addhstbyname (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETHOSTBYNAMEv6:
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addhstbynamev6 (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETHOSTBYADDR:
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addhstbyaddr (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETHOSTBYADDRv6:
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addhstbyaddrv6 (&dbs[serv2db[req->type]], fd, req, key, uid);
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break;
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case GETSTAT:
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case SHUTDOWN:
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case INVALIDATE:
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/* Accept shutdown, getstat and invalidate only from root */
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if (secure_in_use && uid == 0)
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{
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if (req->type == GETSTAT)
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send_stats (fd, dbs);
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else if (req->type == INVALIDATE)
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invalidate_cache (key);
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else
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termination_handler (0);
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}
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else
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{
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/* Some systems have no SO_PEERCRED implementation. They don't
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care about security so we don't as well. */
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#ifdef SO_PEERCRED
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struct ucred caller;
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socklen_t optlen = sizeof (caller);
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if (getsockopt (fd, SOL_SOCKET, SO_PEERCRED, &caller, &optlen) < 0)
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{
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char buf[256];
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dbg_log (_("error getting callers id: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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}
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else
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if (caller.uid == 0)
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#endif
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{
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if (req->type == GETSTAT)
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send_stats (fd, dbs);
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else if (req->type == INVALIDATE)
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invalidate_cache (key);
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else
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termination_handler (0);
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}
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}
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break;
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default:
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/* Ignore the command, it's nothing we know. */
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break;
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}
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}
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/* This is the main loop. It is replicated in different threads but the
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`poll' call makes sure only one thread handles an incoming connection. */
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static void *
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__attribute__ ((__noreturn__))
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nscd_run (void *p)
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{
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long int my_number = (long int) p;
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struct pollfd conn;
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int run_prune = my_number < lastdb && dbs[my_number].enabled;
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time_t now = time (NULL);
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time_t next_prune = now + CACHE_PRUNE_INTERVAL;
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int timeout = run_prune ? 1000 * (next_prune - now) : -1;
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conn.fd = sock;
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conn.events = POLLRDNORM;
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while (1)
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{
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int nr = poll (&conn, 1, timeout);
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if (nr == 0)
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{
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/* The `poll' call timed out. It's time to clean up the cache. */
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assert (my_number < lastdb);
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now = time (NULL);
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prune_cache (&dbs[my_number], now);
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next_prune = now + CACHE_PRUNE_INTERVAL;
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timeout = 1000 * (next_prune - now);
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continue;
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}
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/* We have a new incoming connection. */
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if (conn.revents & (POLLRDNORM|POLLERR|POLLHUP|POLLNVAL))
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{
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/* Accept the connection. */
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int fd = TEMP_FAILURE_RETRY (accept (conn.fd, NULL, NULL));
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request_header req;
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char buf[256];
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uid_t uid = 0;
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if (__builtin_expect (fd, 0) < 0)
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{
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dbg_log (_("while accepting connection: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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continue;
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}
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/* Now read the request. */
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if (__builtin_expect (TEMP_FAILURE_RETRY (read (fd, &req,
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sizeof (req)))
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!= sizeof (req), 0))
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{
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if (debug_level > 0)
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dbg_log (_("short read while reading request: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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close (fd);
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continue;
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}
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/* Some systems have no SO_PEERCRED implementation. They don't
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care about security so we don't as well. */
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#ifdef SO_PEERCRED
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if (secure_in_use)
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{
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struct ucred caller;
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socklen_t optlen = sizeof (caller);
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if (getsockopt (fd, SOL_SOCKET, SO_PEERCRED,
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&caller, &optlen) < 0)
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{
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dbg_log (_("error getting callers id: %s"),
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strerror_r (errno, buf, sizeof (buf)));
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close (fd);
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continue;
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}
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if (req.type < GETPWBYNAME || req.type > LASTDBREQ
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|| secure[serv2db[req.type]])
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uid = caller.uid;
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}
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#endif
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/* It should not be possible to crash the nscd with a silly
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request (i.e., a terribly large key). We limit the size
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to 1kb. */
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if (__builtin_expect (req.key_len, 1) < 0
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|| __builtin_expect (req.key_len, 1) > 1024)
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{
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if (debug_level > 0)
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dbg_log (_("key length in request too long: %d"), req.key_len);
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close (fd);
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continue;
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}
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else
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{
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/* Get the key. */
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char keybuf[req.key_len];
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if (__builtin_expect (TEMP_FAILURE_RETRY (read (fd, keybuf,
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req.key_len))
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!= req.key_len, 0))
|
|
{
|
|
if (debug_level > 0)
|
|
dbg_log (_("short read while reading request key: %s"),
|
|
strerror_r (errno, buf, sizeof (buf)));
|
|
close (fd);
|
|
continue;
|
|
}
|
|
|
|
/* Phew, we got all the data, now process it. */
|
|
handle_request (fd, &req, keybuf, uid);
|
|
|
|
/* We are done. */
|
|
close (fd);
|
|
}
|
|
}
|
|
|
|
if (run_prune)
|
|
{
|
|
now = time (NULL);
|
|
timeout = now < next_prune ? 1000 * (next_prune - now) : 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Start all the threads we want. The initial process is thread no. 1. */
|
|
void
|
|
start_threads (void)
|
|
{
|
|
long int i;
|
|
pthread_attr_t attr;
|
|
pthread_t th;
|
|
|
|
pthread_attr_init (&attr);
|
|
pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
|
|
|
|
/* We allow less than LASTDB threads only for debugging. */
|
|
if (debug_level == 0)
|
|
nthreads = MAX (nthreads, lastdb);
|
|
|
|
for (i = 1; i < nthreads; ++i)
|
|
pthread_create (&th, &attr, nscd_run, (void *) i);
|
|
|
|
pthread_attr_destroy (&attr);
|
|
|
|
nscd_run ((void *) 0);
|
|
}
|
|
|
|
|
|
/* Look up the uid, gid, and supplementary groups to run nscd as. When
|
|
this function is called, we are not listening on the nscd socket yet so
|
|
we can just use the ordinary lookup functions without causing a lockup */
|
|
static void
|
|
begin_drop_privileges (void)
|
|
{
|
|
struct passwd *pwd;
|
|
|
|
pwd = getpwnam (server_user);
|
|
|
|
if (pwd == NULL)
|
|
{
|
|
dbg_log (_("Failed to run nscd as user '%s'"), server_user);
|
|
error (EXIT_FAILURE, 0, _("Failed to run nscd as user '%s'"),
|
|
server_user);
|
|
}
|
|
|
|
server_uid = pwd->pw_uid;
|
|
server_gid = pwd->pw_gid;
|
|
|
|
server_groups = (gid_t *) xmalloc (server_ngroups * sizeof (gid_t));
|
|
|
|
if (getgrouplist (server_user, server_gid, server_groups, &server_ngroups)
|
|
== 0)
|
|
return;
|
|
|
|
server_groups = (gid_t *) xrealloc (server_groups,
|
|
server_ngroups * sizeof (gid_t));
|
|
|
|
if (getgrouplist (server_user, server_gid, server_groups, &server_ngroups)
|
|
== -1)
|
|
{
|
|
dbg_log (_("Failed to run nscd as user '%s'"), server_user);
|
|
error (EXIT_FAILURE, errno, _("getgrouplist failed"));
|
|
}
|
|
}
|
|
|
|
|
|
/* Call setgroups(), setgid(), and setuid() to drop root privileges and
|
|
run nscd as the user specified in the configuration file. */
|
|
static void
|
|
finish_drop_privileges (void)
|
|
{
|
|
if (setgroups (server_ngroups, server_groups) == -1)
|
|
{
|
|
dbg_log (_("Failed to run nscd as user '%s'"), server_user);
|
|
error (EXIT_FAILURE, errno, _("setgroups failed"));
|
|
}
|
|
|
|
if (setgid (server_gid) == -1)
|
|
{
|
|
dbg_log (_("Failed to run nscd as user '%s'"), server_user);
|
|
perror ("setgid");
|
|
exit (1);
|
|
}
|
|
|
|
if (setuid (server_uid) == -1)
|
|
{
|
|
dbg_log (_("Failed to run nscd as user '%s'"), server_user);
|
|
perror ("setuid");
|
|
exit (1);
|
|
}
|
|
}
|