diff options
Diffstat (limited to 'nscd/connections.c')
| -rw-r--r-- | nscd/connections.c | 105 |
1 files changed, 104 insertions, 1 deletions
diff --git a/nscd/connections.c b/nscd/connections.c index 7f7514f8f6..7414ef60a3 100644 --- a/nscd/connections.c +++ b/nscd/connections.c @@ -1,5 +1,5 @@ /* Inner loops of cache daemon. - Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc. + Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. @@ -21,7 +21,10 @@ #include <assert.h> #include <error.h> #include <errno.h> +#include <grp.h> #include <pthread.h> +#include <pwd.h> +#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <libintl.h> @@ -35,6 +38,24 @@ #include "nscd.h" #include "dbg_log.h" +/* Wrapper functions with error checking for standard functions. */ +extern void *xmalloc (size_t n); +extern void *xcalloc (size_t n, size_t s); +extern void *xrealloc (void *o, size_t n); + +/* Support to run nscd as an unprivileged user */ +const char *server_user; +static uid_t server_uid; +static gid_t server_gid; +static gid_t *server_groups; +#ifndef NGROUPS +# define NGROUPS 32 +#endif +static int server_ngroups = NGROUPS; + +static void begin_drop_privileges (void); +static void finish_drop_privileges (void); + /* Mapping of request type to database. */ static const dbtype serv2db[LASTDBREQ + 1] = @@ -125,6 +146,19 @@ nscd_init (const char *conffile) dbg_log (_("cannot read configuration file; this is fatal")); exit (1); } + + /* Secure mode and unprivileged mode are incompatible */ + if (server_user != NULL && secure_in_use) + { + dbg_log (_("Cannot run nscd in secure mode as unprivileged user")); + exit (1); + } + + /* Look up unprivileged uid/gid/groups before we start listening on the + socket */ + if (server_user != NULL) + begin_drop_privileges (); + if (nthreads == -1) /* No configuration for this value, assume a default. */ nthreads = 2 * lastdb; @@ -184,6 +218,10 @@ nscd_init (const char *conffile) strerror (errno)); exit (1); } + + /* Change to unprivileged uid/gid/groups if specifed in config file */ + if (server_user != NULL) + finish_drop_privileges (); } @@ -535,3 +573,68 @@ start_threads (void) 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); + } +} |