busybox/util-linux/setarch.c
Denys Vlasenko 5c527dc57e make 17 state-changing execing applets (ex: "nice PROG ARGS") noexec
The applets with "<applet> [opts] PROG ARGS" API very quickly exec
another program, noexec is okay for them:

 chpst/envdir/envuidgid/softlimit/setuidgid
 chroot
 chrt
 ionice
 nice
 nohup
 setarch/linux32/linux64
 taskset
 cttyhack

"reset" and "sulogin" applets don't have this form, but also exec
another program at once, thus made noexec too.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-04 19:55:01 +02:00

106 lines
3.1 KiB
C

/* vi: set sw=4 ts=4: */
/*
* linux32/linux64 allows for changing uname emulation.
*
* Copyright 2002 Andi Kleen, SuSE Labs.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config SETARCH
//config: bool "setarch (3.4 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: The linux32 utility is used to create a 32bit environment for the
//config: specified program (usually a shell). It only makes sense to have
//config: this util on a system that supports both 64bit and 32bit userland
//config: (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...).
//config:
//config:config LINUX32
//config: bool "linux32 (3.2 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Alias to "setarch linux32".
//config:
//config:config LINUX64
//config: bool "linux64 (3.2 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Alias to "setarch linux64".
//applet:IF_SETARCH(APPLET_NOEXEC(setarch, setarch, BB_DIR_BIN, BB_SUID_DROP, setarch))
// APPLET_NOEXEC:name main location suid_type help
//applet:IF_LINUX32(APPLET_NOEXEC(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
//applet:IF_LINUX64(APPLET_NOEXEC(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
//kbuild:lib-$(CONFIG_SETARCH) += setarch.o
//kbuild:lib-$(CONFIG_LINUX32) += setarch.o
//kbuild:lib-$(CONFIG_LINUX64) += setarch.o
//usage:#define setarch_trivial_usage
//usage: "PERSONALITY [-R] PROG ARGS"
//usage:#define setarch_full_usage "\n\n"
//usage: "PERSONALITY may be:"
//usage: "\n"" linux32 Set 32bit uname emulation"
//usage: "\n"" linux64 Set 64bit uname emulation"
//usage: "\n"
//usage: "\n"" -R Disable address space randomization"
//usage:
//usage:#define linux32_trivial_usage NOUSAGE_STR
//usage:#define linux32_full_usage ""
//usage:
//usage:#define linux64_trivial_usage NOUSAGE_STR
//usage:#define linux64_full_usage ""
#include "libbb.h"
#include <sys/personality.h>
#ifndef ADDR_NO_RANDOMIZE
# define ADDR_NO_RANDOMIZE 0x0040000
#endif
int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int setarch_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
unsigned long pers;
/* Figure out what personality we are supposed to switch to ...
* we can be invoked as either:
* argv[0],argv[1] == "setarch","personality"
* argv[0] == "personality"
*/
if (ENABLE_SETARCH && applet_name[0] == 's'
&& argv[1] && is_prefixed_with(argv[1], "linux")
) {
argv++;
applet_name = argv[0];
}
if ((!ENABLE_SETARCH && !ENABLE_LINUX32) || applet_name[5] == '6')
/* linux64 */
pers = PER_LINUX;
else
if ((!ENABLE_SETARCH && !ENABLE_LINUX64) || applet_name[5] == '3')
/* linux32 */
pers = PER_LINUX32;
else
bb_show_usage();
opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
if (opts)
pers |= ADDR_NO_RANDOMIZE;
/* Try to set personality */
if (personality(pers) < 0)
bb_perror_msg_and_die("personality(0x%lx)", pers);
argv += optind;
if (!argv[0])
(--argv)[0] = (char*)"/bin/sh";
/* Try to execute the program */
BB_EXECVP_or_die(argv);
}