busybox/util-linux/setpriv.c
Denys Vlasenko 6798486141 setpriv: dump user and group info
setpriv from util-linux has an option to dump the current state
regarding privilege settings via '--dump'. It prints out information on
the real and effective user and group IDs, supplementary groups, the
no-new-privs flag, the capability sets as well as secure bits.

This patch is the start of supporting this mode. To make introduction of
the '--dump' easier to reason about, its introduction has been split
into multiple patches. This particular one introduces the ability to
print out user and group information of the current process.

function                                             old     new   delta
setpriv_main                                          89     322    +233
getresuid                                              -      41     +41
getresgid                                              -      41     +41
static.setpriv_longopts                               22      29      +7
packed_usage                                       31675   31669      -6
------------------------------------------------------------------------------
(add/remove: 4/0 grow/shrink: 2/1 up/down: 322/-6)            Total: 316 bytes

Patch by Patrick Steinhardt <ps@pks.im>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-07-04 18:59:11 +02:00

142 lines
3.9 KiB
C

/* vi: set sw=4 ts=4: */
/*
* setpriv implementation for busybox based on linux-utils-ng 2.29
*
* Copyright (C) 2017 by <assafgordon@gmail.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
*/
//config:config SETPRIV
//config: bool "setpriv"
//config: default y
//config: select PLATFORM_LINUX
//config: select LONG_OPTS
//config: help
//config: Run a program with different Linux privilege settings.
//config: Requires kernel >= 3.5
//config:
//config:config FEATURE_SETPRIV_DUMP
//config: bool "Support dumping current privilege state"
//config: default y
//config: depends on SETPRIV
//config: help
//config: Enables the "--dump" switch to print out the current privilege
//config: state. This is helpful for diagnosing problems.
//applet:IF_SETPRIV(APPLET(setpriv, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_SETPRIV) += setpriv.o
//usage:#define setpriv_trivial_usage
//usage: "[OPTIONS] PROG [ARGS]"
//usage:#define setpriv_full_usage "\n\n"
//usage: "Run PROG with different privilege settings\n"
//usage: IF_FEATURE_SETPRIV_DUMP(
//usage: "\n-d,--dump Show current capabilities"
//usage: )
//usage: "\n--nnp,--no-new-privs Ignore setuid/setgid bits and file capabilities"
//setpriv from util-linux 2.28:
// -d, --dump show current state (and do not exec anything)
// --nnp, --no-new-privs disallow granting new privileges
// --inh-caps <caps,...> set inheritable capabilities
// --bounding-set <caps> set capability bounding set
// --ruid <uid> set real uid
// --euid <uid> set effective uid
// --rgid <gid> set real gid
// --egid <gid> set effective gid
// --reuid <uid> set real and effective uid
// --regid <gid> set real and effective gid
// --clear-groups clear supplementary groups
// --keep-groups keep supplementary groups
// --groups <group,...> set supplementary groups
// --securebits <bits> set securebits
// --selinux-label <label> set SELinux label
// --apparmor-profile <pr> set AppArmor profile
#include <sys/prctl.h>
#include "libbb.h"
#ifndef PR_SET_NO_NEW_PRIVS
#define PR_SET_NO_NEW_PRIVS 38
#endif
enum {
IF_FEATURE_SETPRIV_DUMP(OPTBIT_DUMP,)
OPTBIT_NNP,
IF_FEATURE_SETPRIV_DUMP(OPT_DUMP = (1 << OPTBIT_DUMP),)
OPT_NNP = (1 << OPTBIT_NNP),
};
#if ENABLE_FEATURE_SETPRIV_DUMP
static int dump(void)
{
uid_t ruid, euid, suid;
gid_t rgid, egid, sgid;
gid_t *gids;
int ngids;
getresuid(&ruid, &euid, &suid); /* never fails in Linux */
getresgid(&rgid, &egid, &sgid); /* never fails in Linux */
ngids = 0;
gids = bb_getgroups(&ngids, NULL); /* never fails in Linux */
printf("uid: %u\n", (unsigned)ruid);
printf("euid: %u\n", (unsigned)euid);
printf("gid: %u\n", (unsigned)rgid);
printf("egid: %u\n", (unsigned)egid);
printf("Supplementary groups: ");
if (ngids == 0) {
printf("[none]");
} else {
const char *fmt = ",%u" + 1;
int i;
for (i = 0; i < ngids; i++) {
printf(fmt, (unsigned)gids[i]);
fmt = ",%u";
}
}
bb_putchar('\n');
if (ENABLE_FEATURE_CLEAN_UP)
free(gids);
return EXIT_SUCCESS;
}
#endif /* FEATURE_SETPRIV_DUMP */
int setpriv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int setpriv_main(int argc UNUSED_PARAM, char **argv)
{
static const char setpriv_longopts[] ALIGN1 =
IF_FEATURE_SETPRIV_DUMP(
"dump\0" No_argument "d"
)
"nnp\0" No_argument "\xff"
"no-new-privs\0" No_argument "\xff"
;
int opts;
applet_long_options = setpriv_longopts;
opts = getopt32(argv, "+"IF_FEATURE_SETPRIV_DUMP("d"));
argv += optind;
#if ENABLE_FEATURE_SETPRIV_DUMP
if (opts & OPT_DUMP) {
if (argv[0] || (opts - OPT_DUMP) != 0)
bb_show_usage();
return dump();
}
#endif
if (opts & OPT_NNP) {
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0))
bb_simple_perror_msg_and_die("prctl: NO_NEW_PRIVS");
}
if (!argv[0])
bb_show_usage();
BB_EXECVP_or_die(argv);
}