busybox/util-linux/unshare.c

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/* vi: set sw=4 ts=4: */
/*
* Mini unshare implementation for busybox.
*
* Copyright (C) 2016 by Bartosz Golaszewski <bartekgola@gmail.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config UNSHARE
//config: bool "unshare (7.2 kb)"
//config: default y
//config: depends on !NOMMU
//config: select LONG_OPTS
//config: help
//config: Run program with some namespaces unshared from parent.
// needs LONG_OPTS: it is awkward to exclude code which handles --propagation
// and --setgroups based on LONG_OPTS, so instead applet requires LONG_OPTS.
// depends on !NOMMU: we need fork()
//applet:IF_UNSHARE(APPLET(unshare, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_UNSHARE) += unshare.o
//usage:#define unshare_trivial_usage
//usage: "[OPTIONS] [PROG [ARGS]]"
//usage:#define unshare_full_usage "\n"
//usage: "\n -m,--mount[=FILE] Unshare mount namespace"
//usage: "\n -u,--uts[=FILE] Unshare UTS namespace (hostname etc.)"
//usage: "\n -i,--ipc[=FILE] Unshare System V IPC namespace"
//usage: "\n -n,--net[=FILE] Unshare network namespace"
//usage: "\n -p,--pid[=FILE] Unshare PID namespace"
//usage: "\n -U,--user[=FILE] Unshare user namespace"
//usage: "\n -f,--fork Fork before execing PROG"
//usage: "\n -r,--map-root-user Map current user to root (implies -U)"
//usage: "\n --mount-proc[=DIR] Mount /proc filesystem first (implies -m)"
//usage: "\n --propagation slave|shared|private|unchanged"
//usage: "\n Modify mount propagation in mount namespace"
//usage: "\n --setgroups allow|deny Control the setgroups syscall in user namespaces"
#include <sched.h>
#ifndef CLONE_NEWUTS
# define CLONE_NEWUTS 0x04000000
#endif
#ifndef CLONE_NEWIPC
# define CLONE_NEWIPC 0x08000000
#endif
#ifndef CLONE_NEWUSER
# define CLONE_NEWUSER 0x10000000
#endif
#ifndef CLONE_NEWPID
# define CLONE_NEWPID 0x20000000
#endif
#ifndef CLONE_NEWNET
# define CLONE_NEWNET 0x40000000
#endif
#include <sys/mount.h>
#ifndef MS_REC
# define MS_REC (1 << 14)
#endif
#ifndef MS_PRIVATE
# define MS_PRIVATE (1 << 18)
#endif
#ifndef MS_SLAVE
# define MS_SLAVE (1 << 19)
#endif
#ifndef MS_SHARED
# define MS_SHARED (1 << 20)
#endif
#include "libbb.h"
static void mount_or_die(const char *source, const char *target,
const char *fstype, unsigned long mountflags)
{
if (mount(source, target, fstype, mountflags, NULL)) {
bb_perror_msg_and_die("can't mount %s on %s (flags:0x%lx)",
source, target, mountflags);
/* fstype is always either NULL or "proc".
* "proc" is only used to mount /proc.
* No need to clutter up error message with fstype,
* it is easily deductible.
*/
}
}
#define PATH_PROC_SETGROUPS "/proc/self/setgroups"
#define PATH_PROC_UIDMAP "/proc/self/uid_map"
#define PATH_PROC_GIDMAP "/proc/self/gid_map"
struct namespace_descr {
int flag;
const char nsfile4[4];
};
struct namespace_ctx {
char *path;
};
enum {
OPT_mount = 1 << 0,
OPT_uts = 1 << 1,
OPT_ipc = 1 << 2,
OPT_net = 1 << 3,
OPT_pid = 1 << 4,
OPT_user = 1 << 5, /* OPT_user, NS_USR_POS, and ns_list[] index must match! */
OPT_fork = 1 << 6,
OPT_map_root = 1 << 7,
OPT_mount_proc = 1 << 8,
OPT_propagation = 1 << 9,
OPT_setgroups = 1 << 10,
};
enum {
NS_MNT_POS = 0,
NS_UTS_POS,
NS_IPC_POS,
NS_NET_POS,
NS_PID_POS,
NS_USR_POS, /* OPT_user, NS_USR_POS, and ns_list[] index must match! */
NS_COUNT,
};
static const struct namespace_descr ns_list[] = {
{ CLONE_NEWNS, "mnt" },
{ CLONE_NEWUTS, "uts" },
{ CLONE_NEWIPC, "ipc" },
{ CLONE_NEWNET, "net" },
{ CLONE_NEWPID, "pid" },
{ CLONE_NEWUSER, "user" }, /* OPT_user, NS_USR_POS, and ns_list[] index must match! */
};
/*
* Upstream unshare doesn't support short options for --mount-proc,
* --propagation, --setgroups.
* Optional arguments (namespace mountpoints) exist only for long opts,
* we are forced to use "fake" letters for them.
* '+': stop at first non-option.
*/
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
#define OPT_STR "+muinpU""fr""\xfd::""\xfe:""\xff:"
static const char unshare_longopts[] ALIGN1 =
"mount\0" Optional_argument "\xf0"
"uts\0" Optional_argument "\xf1"
"ipc\0" Optional_argument "\xf2"
"net\0" Optional_argument "\xf3"
"pid\0" Optional_argument "\xf4"
"user\0" Optional_argument "\xf5"
"fork\0" No_argument "f"
"map-root-user\0" No_argument "r"
"mount-proc\0" Optional_argument "\xfd"
"propagation\0" Required_argument "\xfe"
"setgroups\0" Required_argument "\xff"
;
/* Ugly-looking string reuse trick */
#define PRIVATE_STR "private\0""unchanged\0""shared\0""slave\0"
#define PRIVATE_UNCHANGED_SHARED_SLAVE PRIVATE_STR
static unsigned long parse_propagation(const char *prop_str)
{
int i = index_in_strings(PRIVATE_UNCHANGED_SHARED_SLAVE, prop_str);
if (i < 0)
bb_error_msg_and_die("unrecognized: --%s=%s", "propagation", prop_str);
if (i == 0)
return MS_REC | MS_PRIVATE;
if (i == 1)
return 0;
if (i == 2)
return MS_REC | MS_SHARED;
return MS_REC | MS_SLAVE;
}
static void mount_namespaces(pid_t pid, struct namespace_ctx *ns_ctx_list)
{
const struct namespace_descr *ns;
struct namespace_ctx *ns_ctx;
int i;
for (i = 0; i < NS_COUNT; i++) {
char nsf[sizeof("/proc/%u/ns/AAAA") + sizeof(int)*3];
ns = &ns_list[i];
ns_ctx = &ns_ctx_list[i];
if (!ns_ctx->path)
continue;
sprintf(nsf, "/proc/%u/ns/%.4s", (unsigned)pid, ns->nsfile4);
mount_or_die(nsf, ns_ctx->path, NULL, MS_BIND);
}
}
int unshare_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unshare_main(int argc UNUSED_PARAM, char **argv)
{
int i;
unsigned int opts;
int unsflags;
uintptr_t need_mount;
const char *proc_mnt_target;
const char *prop_str;
const char *setgrp_str;
unsigned long prop_flags;
uid_t reuid = geteuid();
gid_t regid = getegid();
struct fd_pair fdp;
pid_t child = child; /* for compiler */
struct namespace_ctx ns_ctx_list[NS_COUNT];
memset(ns_ctx_list, 0, sizeof(ns_ctx_list));
proc_mnt_target = "/proc";
prop_str = PRIVATE_STR;
setgrp_str = NULL;
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
opts = getopt32long(argv, "^" OPT_STR "\0"
"\xf0""m" /* long opts (via their "fake chars") imply short opts */
":\xf1""u"
":\xf2""i"
":\xf3""n"
":\xf4""p"
":\xf5""U"
":rU" /* --map-root-user or -r implies -U */
":\xfd""m" /* --mount-proc implies -m */
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
, unshare_longopts,
&proc_mnt_target, &prop_str, &setgrp_str,
&ns_ctx_list[NS_MNT_POS].path,
&ns_ctx_list[NS_UTS_POS].path,
&ns_ctx_list[NS_IPC_POS].path,
&ns_ctx_list[NS_NET_POS].path,
&ns_ctx_list[NS_PID_POS].path,
&ns_ctx_list[NS_USR_POS].path
);
argv += optind;
//bb_error_msg("opts:0x%x", opts);
//bb_error_msg("mount:%s", ns_ctx_list[NS_MNT_POS].path);
//bb_error_msg("proc_mnt_target:%s", proc_mnt_target);
//bb_error_msg("prop_str:%s", prop_str);
//bb_error_msg("setgrp_str:%s", setgrp_str);
//exit(1);
if (setgrp_str) {
if (strcmp(setgrp_str, "allow") == 0) {
if (opts & OPT_map_root) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die(
"--setgroups=allow and --map-root-user "
"are mutually exclusive"
);
}
} else {
/* It's not "allow", must be "deny" */
if (strcmp(setgrp_str, "deny") != 0)
bb_error_msg_and_die("unrecognized: --%s=%s",
"setgroups", setgrp_str);
}
}
unsflags = 0;
need_mount = 0;
for (i = 0; i < NS_COUNT; i++) {
const struct namespace_descr *ns = &ns_list[i];
struct namespace_ctx *ns_ctx = &ns_ctx_list[i];
if (opts & (1 << i))
unsflags |= ns->flag;
need_mount |= (uintptr_t)(ns_ctx->path);
}
/* need_mount != 0 if at least one FILE was given */
prop_flags = MS_REC | MS_PRIVATE;
/* Silently ignore --propagation if --mount is not requested. */
if (opts & OPT_mount)
prop_flags = parse_propagation(prop_str);
/*
* Special case: if we were requested to unshare the mount namespace
* AND to make any namespace persistent (by bind mounting it) we need
* to spawn a child process which will wait for the parent to call
* unshare(), then mount parent's namespaces while still in the
* previous namespace.
*/
fdp.wr = -1;
if (need_mount && (opts & OPT_mount)) {
/*
* Can't use getppid() in child, as we can be unsharing the
* pid namespace.
*/
pid_t ppid = getpid();
xpiped_pair(fdp);
child = xfork();
if (child == 0) {
/* Child */
close(fdp.wr);
/* Wait until parent calls unshare() */
read(fdp.rd, ns_ctx_list, 1); /* ...using bogus buffer */
/*close(fdp.rd);*/
/* Mount parent's unshared namespaces. */
mount_namespaces(ppid, ns_ctx_list);
return EXIT_SUCCESS;
}
/* Parent continues */
}
if (unshare(unsflags) != 0)
bb_perror_msg_and_die("unshare(0x%x)", unsflags);
if (fdp.wr >= 0) {
close(fdp.wr); /* Release child */
close(fdp.rd); /* should close fd, to not confuse exec'ed PROG */
}
if (need_mount) {
/* Wait for the child to finish mounting the namespaces. */
if (opts & OPT_mount) {
int exit_status = wait_for_exitstatus(child);
if (WIFEXITED(exit_status) &&
WEXITSTATUS(exit_status) != EXIT_SUCCESS)
return WEXITSTATUS(exit_status);
} else {
/*
* Regular way - we were requested to mount some other
* namespaces: mount them after the call to unshare().
*/
mount_namespaces(getpid(), ns_ctx_list);
}
}
/*
* When we're unsharing the pid namespace, it's not the process that
* calls unshare() that is put into the new namespace, but its first
* child. The user may want to use this option to spawn a new process
* that'll become PID 1 in this new namespace.
*/
if (opts & OPT_fork) {
xvfork_parent_waits_and_exits();
/* Child continues */
}
if (opts & OPT_map_root) {
char uidmap_buf[sizeof("0 %u 1") + sizeof(int)*3];
/*
* Since Linux 3.19 unprivileged writing of /proc/self/gid_map
* has been disabled unless /proc/self/setgroups is written
* first to permanently disable the ability to call setgroups
* in that user namespace.
*/
xopen_xwrite_close(PATH_PROC_SETGROUPS, "deny");
sprintf(uidmap_buf, "0 %u 1", (unsigned)reuid);
xopen_xwrite_close(PATH_PROC_UIDMAP, uidmap_buf);
sprintf(uidmap_buf, "0 %u 1", (unsigned)regid);
xopen_xwrite_close(PATH_PROC_GIDMAP, uidmap_buf);
} else
if (setgrp_str) {
/* Write "allow" or "deny" */
xopen_xwrite_close(PATH_PROC_SETGROUPS, setgrp_str);
}
if (opts & OPT_mount) {
mount_or_die("none", "/", NULL, prop_flags);
}
if (opts & OPT_mount_proc) {
/*
* When creating a new pid namespace, we might want the pid
* subdirectories in /proc to remain consistent with the new
* process IDs. Without --mount-proc the pids in /proc would
* still reflect the old pid namespace. This is why we make
* /proc private here and then do a fresh mount.
*/
mount_or_die("none", proc_mnt_target, NULL, MS_PRIVATE | MS_REC);
mount_or_die("proc", proc_mnt_target, "proc", MS_NOSUID | MS_NOEXEC | MS_NODEV);
}
exec_prog_or_SHELL(argv);
}