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/* vi: set sw=4 ts=4: */
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* setpriv implementation for busybox based on linux-utils-ng 2.29
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* Copyright (C) 2017 by <assafgordon@gmail.com>
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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//config:config SETPRIV
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//config: bool "setpriv (6.6 kb)"
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//config: select LONG_OPTS
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//config: Run a program with different Linux privilege settings.
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//config: Requires kernel >= 3.5
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//config:config FEATURE_SETPRIV_DUMP
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//config: bool "Support dumping current privilege state"
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//config: depends on SETPRIV
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//config: Enables the "--dump" switch to print out the current privilege
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//config: state. This is helpful for diagnosing problems.
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//config:config FEATURE_SETPRIV_CAPABILITIES
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//config: bool "Support capabilities"
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//config: depends on SETPRIV
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//config: Capabilities can be used to grant processes additional rights
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//config: without the necessity to always execute as the root user.
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//config: Enabling this option enables "--dump" to show information on
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//config: capabilities.
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//config:config FEATURE_SETPRIV_CAPABILITY_NAMES
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//config: bool "Support capability names"
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//config: depends on SETPRIV && FEATURE_SETPRIV_CAPABILITIES
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//config: Capabilities can be either referenced via a human-readble name,
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//config: e.g. "net_admin", or using their index, e.g. "cap_12". Enabling
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//config: this option allows using the human-readable names in addition to
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//config: the index-based names.
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//applet:IF_SETPRIV(APPLET(setpriv, BB_DIR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_SETPRIV) += setpriv.o
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//usage:#define setpriv_trivial_usage
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//usage: "[OPTIONS] PROG ARGS"
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//usage:#define setpriv_full_usage "\n\n"
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//usage: "Run PROG with different privilege settings\n"
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//usage: IF_FEATURE_SETPRIV_DUMP(
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//usage: "\n-d,--dump Show current capabilities"
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//usage: "\n--nnp,--no-new-privs Ignore setuid/setgid bits and file capabilities"
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//usage: IF_FEATURE_SETPRIV_CAPABILITIES(
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//usage: "\n--inh-caps CAP,CAP Set inheritable capabilities"
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//usage: "\n--ambient-caps CAP,CAP Set ambient capabilities"
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//setpriv from util-linux 2.28:
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// -d, --dump show current state (and do not exec anything)
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// --nnp, --no-new-privs disallow granting new privileges
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// --inh-caps <caps,...> set inheritable capabilities
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// --bounding-set <caps> set capability bounding set
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// --ruid <uid> set real uid
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// --euid <uid> set effective uid
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// --rgid <gid> set real gid
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// --egid <gid> set effective gid
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// --reuid <uid> set real and effective uid
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// --regid <gid> set real and effective gid
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// --clear-groups clear supplementary groups
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// --keep-groups keep supplementary groups
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// --groups <group,...> set supplementary groups
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// --securebits <bits> set securebits
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// --selinux-label <label> set SELinux label
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// --apparmor-profile <pr> set AppArmor profile
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#if ENABLE_FEATURE_SETPRIV_CAPABILITIES
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#include <linux/capability.h>
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// #include <sys/capability.h>
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// This header is in libcap, but the functions are in libc.
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// Comment in the header says this above capset/capget:
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/* system calls - look to libc for function to system call mapping */
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extern int capset(cap_user_header_t header, cap_user_data_t data);
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extern int capget(cap_user_header_t header, const cap_user_data_t data);
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// so for bbox, let's just repeat the declarations.
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// This way, libcap needs not be installed in build environment.
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#include <sys/prctl.h>
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#ifndef PR_CAPBSET_READ
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#define PR_CAPBSET_READ 23
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#ifndef PR_SET_NO_NEW_PRIVS
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#define PR_SET_NO_NEW_PRIVS 38
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#ifndef PR_GET_NO_NEW_PRIVS
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#define PR_GET_NO_NEW_PRIVS 39
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#ifndef PR_CAP_AMBIENT
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#define PR_CAP_AMBIENT 47
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#define PR_CAP_AMBIENT_IS_SET 1
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#define PR_CAP_AMBIENT_RAISE 2
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#define PR_CAP_AMBIENT_LOWER 3
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IF_FEATURE_SETPRIV_DUMP(OPTBIT_DUMP,)
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IF_FEATURE_SETPRIV_CAPABILITIES(OPTBIT_INH,)
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IF_FEATURE_SETPRIV_CAPABILITIES(OPTBIT_AMB,)
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IF_FEATURE_SETPRIV_DUMP(OPT_DUMP = (1 << OPTBIT_DUMP),)
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IF_FEATURE_SETPRIV_CAPABILITIES(OPT_INH = (1 << OPTBIT_INH),)
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IF_FEATURE_SETPRIV_CAPABILITIES(OPT_AMB = (1 << OPTBIT_AMB),)
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OPT_NNP = (1 << OPTBIT_NNP),
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#if ENABLE_FEATURE_SETPRIV_CAPABILITIES
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static unsigned parse_cap(const char *cap)
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bb_error_msg_and_die("invalid capability '%s'", cap);
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return cap_name_to_number(cap);
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static void set_inh_caps(char *capstring)
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capstring = strtok_r(capstring, ",", &string);
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cap = parse_cap(capstring);
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if (CAP_TO_INDEX(cap) >= caps.u32s)
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bb_error_msg_and_die("invalid capability '%s'", capstring);
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if (capstring[0] == '+')
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caps.data[CAP_TO_INDEX(cap)].inheritable |= CAP_TO_MASK(cap);
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caps.data[CAP_TO_INDEX(cap)].inheritable &= ~CAP_TO_MASK(cap);
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capstring = strtok_r(NULL, ",", &string);
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if (capset(&caps.header, caps.data) != 0)
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bb_simple_perror_msg_and_die("capset");
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static void set_ambient_caps(char *string)
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cap = strtok_r(string, ",", &string);
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idx = parse_cap(cap);
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, idx, 0, 0) < 0)
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bb_simple_perror_msg("cap_ambient_raise");
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_LOWER, idx, 0, 0) < 0)
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bb_simple_perror_msg("cap_ambient_lower");
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cap = strtok_r(NULL, ",", &string);
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#endif /* FEATURE_SETPRIV_CAPABILITIES */
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#if ENABLE_FEATURE_SETPRIV_DUMP
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# if !ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
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# define printf_cap(pfx, cap_no) printf("%scap_%u", (pfx), (cap_no))
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static int dump(void)
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IF_FEATURE_SETPRIV_CAPABILITIES(struct caps caps;)
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uid_t ruid, euid, suid;
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gid_t rgid, egid, sgid;
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getresuid(&ruid, &euid, &suid); /* never fails in Linux */
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getresgid(&rgid, &egid, &sgid); /* never fails in Linux */
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gids = bb_getgroups(&ngids, NULL); /* never fails in Linux */
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nnp = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
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bb_perror_msg_and_die("prctl: %s", "GET_NO_NEW_PRIVS");
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printf("uid: %u\n", (unsigned)ruid);
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printf("euid: %u\n", (unsigned)euid);
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printf("gid: %u\n", (unsigned)rgid);
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printf("egid: %u\n", (unsigned)egid);
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printf("Supplementary groups: ");
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for (i = 0; i < ngids; i++) {
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printf(fmt, (unsigned)gids[i]);
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printf("\nno_new_privs: %d\n", nnp);
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# if ENABLE_FEATURE_SETPRIV_CAPABILITIES
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printf("Inheritable capabilities: ");
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for (i = 0; cap_valid(i); i++) {
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unsigned idx = CAP_TO_INDEX(i);
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if (idx >= caps.u32s) {
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printf("\nindex: %u u32s: %u capability: %u\n", idx, caps.u32s, i);
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bb_simple_error_msg_and_die("unsupported capability");
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if (caps.data[idx].inheritable & CAP_TO_MASK(i)) {
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printf("\nAmbient capabilities: ");
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for (i = 0; cap_valid(i); i++) {
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int ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, (unsigned long) i, 0UL, 0UL);
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bb_perror_msg_and_die("prctl: %s", "CAP_AMBIENT_IS_SET");
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printf("[unsupported]");
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printf("\nCapability bounding set: ");
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for (i = 0; cap_valid(i); i++) {
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int ret = prctl(PR_CAPBSET_READ, (unsigned long) i, 0UL, 0UL, 0UL);
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bb_perror_msg_and_die("prctl: %s", "CAPBSET_READ");
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if (ENABLE_FEATURE_CLEAN_UP)
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#endif /* FEATURE_SETPRIV_DUMP */
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int setpriv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int setpriv_main(int argc UNUSED_PARAM, char **argv)
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static const char setpriv_longopts[] ALIGN1 =
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IF_FEATURE_SETPRIV_DUMP(
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"dump\0" No_argument "d"
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"nnp\0" No_argument "\xff"
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"no-new-privs\0" No_argument "\xff"
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IF_FEATURE_SETPRIV_CAPABILITIES(
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"inh-caps\0" Required_argument "\xfe"
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"ambient-caps\0" Required_argument "\xfd"
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IF_FEATURE_SETPRIV_CAPABILITIES(char *inh_caps, *ambient_caps;)
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opts = getopt32long(argv, "+"
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IF_FEATURE_SETPRIV_DUMP("d")
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IF_FEATURE_SETPRIV_CAPABILITIES("\xfe:\xfd:"),
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IF_FEATURE_SETPRIV_CAPABILITIES(, &inh_caps, &ambient_caps)
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#if ENABLE_FEATURE_SETPRIV_DUMP
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if (opts & OPT_DUMP) {
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if (argv[0] || (opts - OPT_DUMP) != 0)
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if (opts & OPT_NNP) {
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if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0))
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bb_perror_msg_and_die("prctl: %s", "SET_NO_NEW_PRIVS");
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#if ENABLE_FEATURE_SETPRIV_CAPABILITIES
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set_inh_caps(inh_caps);
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set_ambient_caps(ambient_caps);
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BB_EXECVP_or_die(argv);
added
removed
.pc/platform-linux.diff/util-linux/setpriv.c
