From: Andy Lutomirski <luto@xxxxxxxxxxxxxx> This new command can set no_new_privs, uid, gid, groups, securebits, inheritable caps, the cap bounding set, securebits, and selinux and apparmor labels. [kerolasa@xxxxxx: a lot of small adjustment making the command to be a good fit in util-linux project] Signed-off-by: Sami Kerola <kerolasa@xxxxxx> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx> --- Changes since Andy Lutomirski's V2 at Mon, 14 Jan 2013. - Align man page with Documentation/howto-man-page.txt - Clean up usage output. - Re-use messages making translators to work less. - Make some messages easier to understand. - Drop bool usage, use bit fields instead. - Fix smatch warnings. - Remove unnecessary braces where possible. - Tidy few code style issues. .gitignore | 1 + configure.ac | 14 + sys-utils/Makemodule.am | 7 + sys-utils/setpriv.1 | 149 +++++++++ sys-utils/setpriv.c | 814 ++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 985 insertions(+) create mode 100644 sys-utils/setpriv.1 create mode 100644 sys-utils/setpriv.c diff --git a/.gitignore b/.gitignore index b2e9d6d..7dbb81c 100644 --- a/.gitignore +++ b/.gitignore @@ -150,6 +150,7 @@ tests/run.sh.trs /script /scriptreplay /setarch +/setpriv /setsid /setterm /sfdisk diff --git a/configure.ac b/configure.ac index 9024809..d3a8e9e 100644 --- a/configure.ac +++ b/configure.ac @@ -879,6 +879,20 @@ if test "x$build_nsenter" = xyes; then AC_CHECK_FUNCS([setns]) fi +dnl setpriv depends on libcap-ng. It would be possible to build +dnl a version of setpriv with limited functionality without libcap-ng, +dnl but this isn't currently supported. +UL_CHECK_LIB([cap-ng], [capng_apply], [cap_ng]) +AC_ARG_ENABLE([setpriv], + AS_HELP_STRING([--disable-setpriv], [do not build setpriv]), + [], enable_setpriv=check +) +UL_BUILD_INIT([setpriv]) +UL_REQUIRES_LINUX([setpriv]) +UL_REQUIRES_HAVE([setpriv], [cap_ng], [libcap-ng]) +AM_CONDITIONAL(BUILD_SETPRIV, test "x$build_setpriv" = xyes) + + AC_ARG_ENABLE([arch], AS_HELP_STRING([--enable-arch], [do build arch]), [], enable_arch=no diff --git a/sys-utils/Makemodule.am b/sys-utils/Makemodule.am index 978d97f..86c529e 100644 --- a/sys-utils/Makemodule.am +++ b/sys-utils/Makemodule.am @@ -318,3 +318,10 @@ if HAVE_AUDIT hwclock_LDADD += -laudit endif endif # BUILD_HWCLOCK + +if BUILD_SETPRIV +usrbin_exec_PROGRAMS += setpriv +dist_man_MANS += sys-utils/setpriv.1 +setpriv_SOURCES = sys-utils/setpriv.c +setpriv_LDADD = $(LDADD) -lcap-ng libcommon.la +endif diff --git a/sys-utils/setpriv.1 b/sys-utils/setpriv.1 new file mode 100644 index 0000000..c56d89f --- /dev/null +++ b/sys-utils/setpriv.1 @@ -0,0 +1,149 @@ +.TH SETPRIV 1 "January 2013" "util-linux" "User Commands" +.SH NAME +setpriv \- run a program with different Linux privilege settings +.SH SYNOPSIS +.B setpriv +.RI [ options ] +program +.RI [ arguments ] +.SH DESCRIPTION +Sets or queries various Linux privilege settings that are inherited across +.BR execve (2). +.SH OPTION +.TP +\fB\-d\fR, \fB\-\-dump\fR +Dumps current privilege state. Specify more than once to show extra, mostly +useless, information. Incompatible with all other options. +.TP +\fB\-\-no\-new\-privs\fR +Sets the +.I no_\:new_\:privs +bit. With this bit set, +.BR execve (2) +will not grant new privileges. For example, the setuid and setgid bits as well +as file capabilities will be disabled. (Executing binaries with these bits set +will still work, but they will not gain privilege. Certain LSMs, especially +AppArmor, may result in failures to execute certain programs.) This bit is +inherited by child processes and cannot be unset. See +.BR prctl (2) +and +.IR Documentation/\:prctl/\:no_\:new_\:privs.txt +in the Linux kernel source. +.IP +The no_\:new_\:privs bit is supported since Linux 3.5. +.TP +\fB\-\-inh\-caps\fR \fI(+|\-)cap\fR,\fI...\fR or \fB\-\-bounding\-set\fR \fI(+|\-)cap\fR,\fI...\fR +Sets inheritable capabilities or capability bounding set. See +.BR capabilities (7). +The argument is a comma-separated list of +.I +cap +and +.I \-cap +entries, which add or remove an entry respectively. +.I +all +and +.I \-all +can be used to add or remove all caps. The set of capabilities starts out as +the current inheritable set for +.B \-\-\:inh\-\:caps +and the current bounding set for +.BR \-\-\:bounding\-\:set . +If you drop something from the bounding set without also dropping it from the +inheritable set, you are likely to become confused. Do not do that. +.TP +.BR \-\-list\-caps +Lists all known capabilities. Must be specified alone. +.TP +\fB\-\-ruid\fR \fIuid\fR, \fB\-\-euid\fR \fIuid\fR, \fB\-\-reuid\fR \fIuid\fR +Sets the real, effective, or both \fIuid\fRs. +.IP +Setting +.I uid +or +.I gid +does not change capabilities, although the exec call at the end might change +capabilities. This means that, if you are root, you probably want to do +something like: +.IP +\-\-reuid=1000 \-\-\:regid=1000 \-\-\:caps=\-\:all +.TP +\fB\-\-rgid\fR \fIgid\fR, \fB\-\-egid\fR \fIgid\fR, \fB\-\-regid\fR \fIgid\fR +Sets the real, effective, or both \fIgid\fRs. +.IP +For safety, you must specify one of \-\-\:keep\-\:groups, +\-\-\:clear\-\:groups, or \-\-\:groups if you set any primary +.IR gid . +.TP +.BR \-\-clear\-groups +Clears supplementary groups. +.TP +\fB\-\-keep\-groups\fR +Preserves supplementary groups. Only useful in conjunction with \-\-rgid, +\-\-egid, or \-\-regid. +.TP +\fB\-\-groups\fR \fIgroup\fR,\fI...\fR +Sets supplementary groups. +.TP +\fB\-\-securebits\fR \fI(+|\-)securebit\fR,\fI...\fR +Sets or clears securebits. The valid securebits are +.IR noroot , +.IR noroot_\:locked , +.IR no_\:setuid_\:fixup , +.IR no_\:setuid_\:fixup_\:locked , +and +.IR keep_\:caps_\:locked . +.I keep_\:caps +is cleared by +.BR execve (2) +and is therefore not allowed. +.TP +\fB\-\-selinux\-label\fR \fIlabel\fR +Requests a particular SELinux transition (using a transition on exec, not +dyntrans). This will fail and cause +.BR setpriv (1) +to abort if SELinux is not in use, and the transition may be ignored or cause +.BR execve (2) +to fail at SELinux's whim. (In particular, this is unlikely to work in +conjunction with +.IR no_\:new_\:privs .) +This is similar to +.BR runcon (1). +.TP +\fB\-\-apparmor\-profile\fR \fIprofile\fR +Requests a particular AppArmor profile (using a transition on exec). This will +fail and cause +.BR setpriv (1) +to abort if AppArmor is not in use, and the transition may be ignored or cause +.BR execve (2) +to fail at AppArmor's whim. +.TP +\fB\-V\fR, \fB\-\-version\fR +Display version information and exit. +.TP +\fB\-h\fR, \fB\-\-help\fR +Display help and exit. +.SH NOTES +If applying any specified option fails, +.I program +will not be run and +.B setpriv +will return with exit code 127. +.PP +Be careful with this tool \-\- it may have unexpected security consequences. +For example, setting no_\:new_\:privs and then execing a program that is +SELinux\-\:confined (as this tool would do) may prevent the SELinux +restrictions from taking effect. +.SH SEE ALSO +.BR prctl (2) +.BR capability (7) +.SH AUTHOR +.MT luto@xxxxxxxxxxxxxx +Andy Lutomirski +.ME +.SH AVAILABILITY +The +.B setpriv +command is part of the util-linux package and is available from +.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/ +Linux Kernel Archive +.UE . diff --git a/sys-utils/setpriv.c b/sys-utils/setpriv.c new file mode 100644 index 0000000..1662daf --- /dev/null +++ b/sys-utils/setpriv.c @@ -0,0 +1,814 @@ +/* + * setpriv(1) - set various kernel privilege bits and run something + * + * Copyright (C) 2012 Andy Lutomirski <luto@xxxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <cap-ng.h> +#include <errno.h> +#include <getopt.h> +#include <grp.h> +#include <linux/securebits.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/prctl.h> +#include <unistd.h> + +#include "bitops.h" +#include "c.h" +#include "closestream.h" +#include "nls.h" +#include "optutils.h" +#include "strutils.h" +#include "xalloc.h" + +#ifndef PR_SET_NO_NEW_PRIVS +# define PR_SET_NO_NEW_PRIVS 38 +#endif +#ifndef PR_GET_NO_NEW_PRIVS +# define PR_GET_NO_NEW_PRIVS 39 +#endif + +#define SETPRIV_EXIT_PRIVERR 127 /* how we exit when we fail to set privs */ + +/* + * Note: We are subject to https://bugzilla.redhat.com/show_bug.cgi?id=895105 + * and we will therefore have problems if new capabilities are added. Once + * that bug is fixed, I'll (Andy Lutomirski) submit a corresponding fix to + * setpriv. In the mean time, the code here tries to work reasonably well. + */ + +struct privctx { + /* bit arrays -- see include/bitops.h */ + unsigned int + nnp:1, /* no_new_privs */ + have_ruid:1, /* real uid */ + have_euid:1, /* effective uid */ + have_rgid:1, /* real gid */ + have_egid:1, /* effective gid */ + have_groups:1, /* add groups */ + keep_groups:1, /* keep groups */ + clear_groups:1, /* remove groups */ + have_securebits:1; /* remove groups */ + + /* uids and gids */ + uid_t ruid, euid; + gid_t rgid, egid; + + /* supplementary groups */ + size_t num_groups; + gid_t *groups; + + /* caps */ + const char *caps_to_inherit; + const char *bounding_set; + + /* securebits */ + int securebits; + + /* LSMs */ + const char *selinux_label; + const char *apparmor_profile; +}; + +static void __attribute__((__noreturn__)) usage(FILE *out) +{ + fputs(USAGE_HEADER, out); + fprintf(out, _(" %s [options] <program> [args...]\n"), program_invocation_short_name); + fputs(USAGE_OPTIONS, out); + fputs(_(" -d, --dump show current state (and do not exec anything)\n"), out); + fputs(_(" --nnp, --no-new-privs disallow granting new privileges\n"), out); + fputs(_(" --inh-caps <caps,...> set inheritable capabilities\n"), out); + fputs(_(" --bounding-set <caps> set capability bounding set\n"), out); + fputs(_(" --ruid <uid> set real uid\n"), out); + fputs(_(" --euid <uid> set effective uid\n"), out); + fputs(_(" --rgid <gid> set real gid\n"), out); + fputs(_(" --egid <gid> set effective gid\n"), out); + fputs(_(" --reuid <uid> set real and effective uid\n"), out); + fputs(_(" --regid <gid> set real and effective gid\n"), out); + fputs(_(" --clear-groups clear supplementary groups\n"), out); + fputs(_(" --keep-groups keep supplementary groups\n"), out); + fputs(_(" --groups <group,...> set supplementary groups\n"), out); + fputs(_(" --securebits <bits> set securebits\n"), out); + fputs(_(" --selinux-label <label> set SELinux label (requires process:transition)\n"), out); + fputs(_(" --apparmor-profile <pr> set AppArmor profile (requires onexec permission)\n"), out); + fputs(USAGE_SEPARATOR, out); + fputs(USAGE_HELP, out); + fputs(USAGE_VERSION, out); + fputs(USAGE_SEPARATOR, out); + fputs(_(" This tool can be dangerous. Read the manpage, and be careful.\n"), out); + fprintf(out, USAGE_MAN_TAIL("setpriv(1)")); + + exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS); +} + +static int real_cap_last_cap(void) +{ + /* CAP_LAST_CAP is untrustworthy. */ + static int ret = -1; + int matched; + FILE *f; + + if (ret != -1) + return ret; + + f = fopen("/proc/sys/kernel/cap_last_cap", "r"); + if (!f) { + ret = CAP_LAST_CAP; /* guess */ + return ret; + } + + matched = fscanf(f, "%d", &ret); + fclose(f); + + if (matched != 1) + ret = CAP_LAST_CAP; /* guess */ + + return ret; +} + +/* Returns the number of capabilities printed. */ +static int print_caps(FILE *f, capng_type_t which) +{ + int i, n = 0, max = real_cap_last_cap(); + + for (i = 0; i <= max; i++) { + if (capng_have_capability(which, i)) { + const char *name = capng_capability_to_name(i); + if (n) + fputc(',', f); + if (name) + fputs(name, f); + else + /* cap-ng has very poor handling of + * CAP_LAST_CAP changes. This is the + * best we can do. */ + printf("cap_%d", i); + n++; + } + } + return n; +} + +static void dump_one_secbit(int *first, int *bits, int bit, const char *name) +{ + if (*bits & bit) { + if (!*first) + printf(","); + else + *first = 0; + fputs(name, stdout); + *bits &= ~bit; + } +} + +static void dump_securebits(void) +{ + int first = 1; + int bits = prctl(PR_GET_SECUREBITS, 0, 0, 0, 0); + + if (bits < 0) { + warnx(_("getting process secure bits failed")); + return; + } + + printf(_("Securebits: ")); + + dump_one_secbit(&first, &bits, SECBIT_NOROOT, "noroot"); + dump_one_secbit(&first, &bits, SECBIT_NOROOT_LOCKED, "noroot_locked"); + dump_one_secbit(&first, &bits, SECBIT_NO_SETUID_FIXUP, + "no_setuid_fixup"); + dump_one_secbit(&first, &bits, SECBIT_NO_SETUID_FIXUP_LOCKED, + "no_setuid_fixup_locked"); + bits &= ~SECBIT_KEEP_CAPS; + dump_one_secbit(&first, &bits, SECBIT_KEEP_CAPS_LOCKED, + "keep_caps_locked"); + if (bits) { + if (!first) + printf(","); + else + first = 0; + printf("0x%x", (unsigned)bits); + } + + if (first) + printf(_("[none]\n")); + else + printf("\n"); +} + +static void dump_label(const char *name) +{ + char buf[4097]; + ssize_t len; + int fd, e; + + fd = open("/proc/self/attr/current", O_RDONLY); + if (fd == -1) { + warnx(_("cannot open %s"), "/proc/self/attr/current"); + return; + } + + len = read(fd, buf, sizeof(buf)); + e = errno; + close(fd); + if (len < 0) { + errno = e; + warnx(_("read failed: %s"), name); + return; + } + if (sizeof(buf) - 1 <= (size_t)len) { + warnx(_("%s: too long"), name); + return; + } + + buf[len] = 0; + if (0 < len && buf[len - 1] == '\n') + buf[len - 1] = 0; + printf("%s: %s\n", name, buf); +} + +static void dump_groups(void) +{ + int n = getgroups(0, 0); + gid_t *groups; + if (n < 0) { + warn("getgroups failed"); + return; + } + + groups = alloca(n * sizeof(gid_t)); + n = getgroups(n, groups); + if (n < 0) { + warn("getgroups failed"); + return; + } + + printf(_("Supplementary groups: ")); + if (n == 0) + printf(_("[none]")); + else { + int i; + for (i = 0; i < n; i++) { + if (0 < i) + printf(","); + printf("%ld", (long)groups[i]); + } + } + printf("\n"); +} + +static void dump(int dumplevel) +{ + int x; + uid_t ru, eu, su; + gid_t rg, eg, sg; + + if (getresuid(&ru, &eu, &su) == 0) { + printf(_("uid: %u\n"), ru); + printf(_("euid: %u\n"), eu); + /* Saved and fs uids always equal euid. */ + if (3 <= dumplevel) + printf(_("suid: %u\n"), su); + } else + warn(_("getresuid failed")); + + if (getresgid(&rg, &eg, &sg) == 0) { + printf("gid: %ld\n", (long)rg); + printf("egid: %ld\n", (long)eg); + /* Saved and fs gids always equal egid. */ + if (dumplevel >= 3) + printf("sgid: %ld\n", (long)sg); + } else + warn(_("getresgid failed")); + + dump_groups(); + + x = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); + if (0 <= x) + printf("no_new_privs: %d\n", x); + else + warn("setting no_new_privs failed"); + + if (2 <= dumplevel) { + printf(_("Effective capabilities: ")); + if (print_caps(stdout, CAPNG_EFFECTIVE) == 0) + printf(_("[none]")); + printf("\n"); + + printf(_("Permitted capabilities: ")); + if (print_caps(stdout, CAPNG_PERMITTED) == 0) + printf(_("[none]")); + printf("\n"); + } + + printf(_("Inheritable capabilities: ")); + if (print_caps(stdout, CAPNG_INHERITABLE) == 0) + printf(_("[none]")); + printf("\n"); + + printf(_("Capability bounding set: ")); + if (print_caps(stdout, CAPNG_BOUNDING_SET) == 0) + printf(_("[none]")); + printf("\n"); + + dump_securebits(); + + if (access("/sys/fs/selinux", F_OK) == 0) + dump_label(_("SELinux label")); + + if (access("/sys/kernel/security/apparmor", F_OK) == 0) { + dump_label(_("AppArmor profile")); + } +} + +static void list_known_caps(void) +{ + int i, max = real_cap_last_cap(); + + for (i = 0; i <= max; i++) { + const char *name = capng_capability_to_name(i); + if (name) + printf("%s\n", name); + else + warnx(_("cap %d: libcap-ng is broken"), i); + } +} + +static void parse_groups(struct privctx *opts, const char *str) +{ + char *groups = xstrdup(str); + char *buf = groups; /* We'll reuse it */ + char *c; + size_t i = 0; + + opts->have_groups = 1; + opts->num_groups = 0; + while ((c = strsep(&groups, ","))) + opts->num_groups++; + + /* Start again */ + strcpy(buf, str); /* It's exactly the right length */ + groups = buf; + + opts->groups = xcalloc(opts->num_groups, sizeof(gid_t)); + while ((c = strsep(&groups, ","))) + opts->groups[i++] = (gid_t) strtol_or_err(c, + _("Invalid supplementary group id")); + + free(groups); +} + +static void do_setresuid(const struct privctx *opts) +{ + uid_t ruid, euid, suid; + if (getresuid(&ruid, &euid, &suid) != 0) + err(SETPRIV_EXIT_PRIVERR, _("getresuid failed")); + if (opts->have_ruid) + ruid = opts->ruid; + if (opts->have_euid) + euid = opts->euid; + + /* Also copy effective to saved (for paranoia). */ + if (setresuid(ruid, euid, euid) != 0) + err(SETPRIV_EXIT_PRIVERR, _("setresuid failed")); +} + +static void do_setresgid(const struct privctx *opts) +{ + gid_t rgid, egid, sgid; + if (getresgid(&rgid, &egid, &sgid) != 0) + err(SETPRIV_EXIT_PRIVERR, _("getresgid failed")); + if (opts->have_rgid) + rgid = opts->rgid; + if (opts->have_egid) + egid = opts->egid; + + /* Also copy effective to saved (for paranoia). */ + if (setresgid(rgid, egid, egid) != 0) + err(SETPRIV_EXIT_PRIVERR, _("setresgid failed")); +} + +static void bump_cap(unsigned int cap) +{ + if (capng_have_capability(CAPNG_PERMITTED, cap)) + capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, cap); +} + +static void do_caps(capng_type_t type, const char *caps) +{ + char *my_caps = xstrdup(caps); + char *c; + + while ((c = strsep(&my_caps, ","))) { + capng_act_t action; + if (*c == '+') + action = CAPNG_ADD; + else if (*c == '-') + action = CAPNG_DROP; + else + errx(EXIT_FAILURE, _("bad capability string")); + + if (!strcmp(c + 1, "all")) { + int i; + /* It would be really bad if -all didn't drop all + * caps. It's better to just fail. */ + if (real_cap_last_cap() > CAP_LAST_CAP) + errx(SETPRIV_EXIT_PRIVERR, + _("libcap-ng is too old for \"all\" caps")); + for (i = 0; i <= CAP_LAST_CAP; i++) + capng_update(action, type, i); + } else { + int cap = capng_name_to_capability(c + 1); + if (0 <= cap) + capng_update(action, type, cap); + else + errx(EXIT_FAILURE, + _("unknown capability \"%s\""), c + 1); + } + } + + free(my_caps); +} + +static void parse_securebits(struct privctx *opts, const char *arg) +{ + char *buf = xstrdup(arg); + char *c; + + opts->have_securebits = 1; + opts->securebits = prctl(PR_GET_SECUREBITS, 0, 0, 0, 0); + if (opts->securebits < 0) + err(SETPRIV_EXIT_PRIVERR, _("getting process secure bits failed")); + + if (opts->securebits & ~(int)(SECBIT_NOROOT | + SECBIT_NOROOT_LOCKED | + SECBIT_NO_SETUID_FIXUP | + SECBIT_NO_SETUID_FIXUP_LOCKED | + SECBIT_KEEP_CAPS | + SECBIT_KEEP_CAPS_LOCKED)) + errx(SETPRIV_EXIT_PRIVERR, + _("unrecognized securebit set -- refusing to adjust")); + + while ((c = strsep(&buf, ","))) { + if (*c != '+' && *c != '-') + errx(EXIT_FAILURE, _("bad securebits string")); + + if (!strcmp(c + 1, "all")) { + if (*c == '-') + opts->securebits = 0; + else + errx(EXIT_FAILURE, + _("+all securebits is not allowed")); + } else { + int bit; + if (!strcmp(c + 1, "noroot")) + bit = SECBIT_NOROOT; + else if (!strcmp(c + 1, "noroot_locked")) + bit = SECBIT_NOROOT_LOCKED; + else if (!strcmp(c + 1, "no_setuid_fixup")) + bit = SECBIT_NO_SETUID_FIXUP; + else if (!strcmp(c + 1, "no_setuid_fixup_locked")) + bit = SECBIT_NO_SETUID_FIXUP_LOCKED; + else if (!strcmp(c + 1, "keep_caps")) + errx(EXIT_FAILURE, + _("adjusting keep_caps does not make sense")); + else if (!strcmp(c + 1, "keep_caps_locked")) + bit = SECBIT_KEEP_CAPS_LOCKED; /* sigh */ + else + errx(EXIT_FAILURE, _("unrecognized securebit")); + + if (*c == '+') + opts->securebits |= bit; + else + opts->securebits &= ~bit; + } + } + + opts->securebits |= SECBIT_KEEP_CAPS; /* We need it, and it's reset on exec */ + + free(buf); +} + +static void do_selinux_label(const char *label) +{ + int fd; + size_t len; + + if (access("/sys/fs/selinux", F_OK) != 0) + errx(SETPRIV_EXIT_PRIVERR, _("SELinux is not running")); + + fd = open("/proc/self/attr/exec", O_RDWR); + if (fd == -1) + err(SETPRIV_EXIT_PRIVERR, + _("cannot open %s"), "/proc/self/attr/exec"); + + len = strlen(label); + errno = 0; + if (write(fd, label, len) != (ssize_t) len) + err(SETPRIV_EXIT_PRIVERR, + _("write failed: %s"), "/proc/self/attr/exec"); + + close(fd); +} + +static void do_apparmor_profile(const char *label) +{ + FILE *f; + + if (access("/sys/kernel/security/apparmor", F_OK) != 0) + errx(SETPRIV_EXIT_PRIVERR, _("AppArmor is not running")); + + f = fopen("/proc/self/attr/exec", "wx"); + if (!f) + err(SETPRIV_EXIT_PRIVERR, + _("cannot open %s"), "/proc/self/attr/exec"); + + if (fprintf(f, "changeprofile %s", label) < 0 || fflush(f) != 0 + || fclose(f) != 0) + err(SETPRIV_EXIT_PRIVERR, + _("write failed: %s"), "/proc/self/attr/exec"); +} + +int main(int argc, char **argv) +{ + enum { + NNP = CHAR_MAX + 1, + RUID, + EUID, + RGID, + EGID, + REUID, + REGID, + CLEAR_GROUPS, + KEEP_GROUPS, + GROUPS, + INHCAPS, + LISTCAPS, + CAPBSET, + SECUREBITS, + SELINUX_LABEL, + APPARMOR_PROFILE + }; + + static const struct option longopts[] = { + {"dump", no_argument, 0, 'd'}, + {"nnp", no_argument, 0, NNP}, + {"no-new-privs", no_argument, 0, NNP}, + {"inh-caps", required_argument, 0, INHCAPS}, + {"list-caps", no_argument, 0, LISTCAPS}, + {"ruid", required_argument, 0, RUID}, + {"euid", required_argument, 0, EUID}, + {"rgid", required_argument, 0, RGID}, + {"egid", required_argument, 0, EGID}, + {"reuid", required_argument, 0, REUID}, + {"regid", required_argument, 0, REGID}, + {"clear-groups", no_argument, 0, CLEAR_GROUPS}, + {"keep-groups", no_argument, 0, KEEP_GROUPS}, + {"groups", required_argument, 0, GROUPS}, + {"bounding-set", required_argument, 0, CAPBSET}, + {"securebits", required_argument, 0, SECUREBITS}, + {"selinux-label", required_argument, 0, SELINUX_LABEL}, + {"apparmor-profile", required_argument, 0, APPARMOR_PROFILE}, + {"help", no_argument, 0, 'h'}, + {"version", no_argument, 0, 'V'}, + {NULL, 0, 0, 0} + }; + + static const ul_excl_t excl[] = { + /* keep in same order with enum definitions */ + {CLEAR_GROUPS, KEEP_GROUPS, GROUPS}, + {0} + }; + int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT; + + int c; + struct privctx opts; + int dumplevel = 0; + int total_opts = 0; + int list_caps = 0; + + setlocale(LC_MESSAGES, ""); + bindtextdomain(PACKAGE, LOCALEDIR); + textdomain(PACKAGE); + atexit(close_stdout); + + memset(&opts, 0, sizeof(opts)); + + while ((c = getopt_long(argc, argv, "+dhV", longopts, NULL)) != -1) { + err_exclusive_options(c, longopts, excl, excl_st); + total_opts++; + switch (c) { + case 'd': + dumplevel++; + break; + case NNP: + if (opts.nnp) + errx(EXIT_FAILURE, + _("duplicate --no-new-privs option")); + opts.nnp = 1; + break; + case RUID: + if (opts.have_ruid) + errx(EXIT_FAILURE, _("duplicate ruid")); + opts.have_ruid = 1; + opts.ruid = strtol_or_err(optarg, + _("failed to parse ruid")); + break; + case EUID: + if (opts.have_euid) + errx(EXIT_FAILURE, _("duplicate euid")); + opts.have_euid = 1; + opts.euid = strtol_or_err(optarg, + _("failed to parse euid")); + break; + case REUID: + if (opts.have_ruid || opts.have_euid) + errx(EXIT_FAILURE, _("duplicate ruid or euid")); + opts.have_ruid = opts.have_euid = 1; + opts.ruid = opts.euid = strtol_or_err(optarg, + _("failed to parse reuid")); + break; + case RGID: + if (opts.have_rgid) + errx(EXIT_FAILURE, _("duplicate rgid")); + opts.have_rgid = 1; + opts.rgid = strtol_or_err(optarg, + _("failed to parse rgid")); + break; + case EGID: + if (opts.have_egid) + errx(EXIT_FAILURE, _("duplicate egid")); + opts.have_egid = 1; + opts.egid = strtol_or_err(optarg, + _("failed to parse egid")); + break; + case REGID: + if (opts.have_rgid || opts.have_egid) + errx(EXIT_FAILURE, _("duplicate rgid or egid")); + opts.have_rgid = opts.have_egid = 1; + opts.rgid = opts.egid = strtol_or_err(optarg, + _("failed to parse regid")); + break; + case CLEAR_GROUPS: + if (opts.clear_groups) + errx(EXIT_FAILURE, + _("duplicate --clear-groups option")); + opts.clear_groups = 1; + break; + case KEEP_GROUPS: + if (opts.keep_groups) + errx(EXIT_FAILURE, + _("duplicate --keep-groups option")); + opts.keep_groups = 1; + break; + case GROUPS: + if (opts.have_groups) + errx(EXIT_FAILURE, + _("duplicate --groups option")); + parse_groups(&opts, optarg); + break; + case LISTCAPS: + list_caps = 1; + break; + case INHCAPS: + if (opts.caps_to_inherit) + errx(EXIT_FAILURE, + _("duplicate --caps option")); + opts.caps_to_inherit = optarg; + break; + case CAPBSET: + if (opts.bounding_set) + errx(EXIT_FAILURE, + _("duplicate --bounding-set option")); + opts.bounding_set = optarg; + break; + case SECUREBITS: + if (opts.have_securebits) + errx(EXIT_FAILURE, + _("duplicate --securebits option")); + parse_securebits(&opts, optarg); + break; + case SELINUX_LABEL: + if (opts.selinux_label) + errx(EXIT_FAILURE, + _("duplicate --selinux-label option")); + opts.selinux_label = optarg; + break; + case APPARMOR_PROFILE: + if (opts.apparmor_profile) + errx(EXIT_FAILURE, + _("duplicate --apparmor-profile option")); + opts.apparmor_profile = optarg; + break; + case 'h': + usage(stdout); + case 'V': + printf(UTIL_LINUX_VERSION); + return EXIT_SUCCESS; + case '?': + usage(stderr); + default: + errx(EXIT_FAILURE, _("unrecognized option '%c'"), c); + } + } + + if (dumplevel) { + if (total_opts != dumplevel || optind < argc) + errx(EXIT_FAILURE, + _("--dump is incompatible with all other options")); + dump(dumplevel); + return EXIT_SUCCESS; + } + + if (list_caps) { + if (total_opts != 1 || optind < argc) + errx(EXIT_FAILURE, + _("--list-caps must be specified alone")); + list_known_caps(); + return EXIT_SUCCESS; + } + + if (argc <= optind) + errx(EXIT_FAILURE, _("No program specified")); + + if ((opts.have_rgid || opts.have_egid) + && !opts.keep_groups && !opts.clear_groups && !opts.have_groups) + errx(EXIT_FAILURE, + _("--[re]gid requires --keep-groups, --clear-groups, or --groups")); + + if (opts.nnp) + if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1) + err(EXIT_FAILURE, _("disallow granting new privileges failed")); + + if (opts.selinux_label) + do_selinux_label(opts.selinux_label); + if (opts.apparmor_profile) + do_apparmor_profile(opts.apparmor_profile); + + if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) + err(EXIT_FAILURE, _("keep process capabilities failed")); + + /* We're going to want CAP_SETPCAP, CAP_SETUID, and CAP_SETGID if + * possible. */ + bump_cap(CAP_SETPCAP); + bump_cap(CAP_SETUID); + bump_cap(CAP_SETGID); + if (capng_apply(CAPNG_SELECT_CAPS) != 0) + err(SETPRIV_EXIT_PRIVERR, _("activate capabilities")); + + if (opts.have_ruid || opts.have_euid) { + do_setresuid(&opts); + /* KEEPCAPS doesn't work for the effective mask. */ + if (capng_apply(CAPNG_SELECT_CAPS) != 0) + err(SETPRIV_EXIT_PRIVERR, _("reactivate capabilities")); + } + + if (opts.have_rgid || opts.have_egid) + do_setresgid(&opts); + + if (opts.have_groups) { + if (setgroups(opts.num_groups, opts.groups) != 0) + err(SETPRIV_EXIT_PRIVERR, _("setgroups failed")); + } else if (opts.clear_groups) { + gid_t x = 0; + if (setgroups(0, &x) != 0) + err(SETPRIV_EXIT_PRIVERR, _("setgroups failed")); + } + + if (opts.have_securebits) + if (prctl(PR_SET_SECUREBITS, opts.securebits, 0, 0, 0) != 0) + err(SETPRIV_EXIT_PRIVERR, _("set procecess securebits failed")); + + if (opts.bounding_set) { + do_caps(CAPNG_BOUNDING_SET, opts.bounding_set); + errno = EPERM; /* capng doesn't set errno if we're missing CAP_SETPCAP */ + if (capng_apply(CAPNG_SELECT_BOUNDS) != 0) + err(SETPRIV_EXIT_PRIVERR, _("apply bounding set")); + } + + if (opts.caps_to_inherit) { + do_caps(CAPNG_INHERITABLE, opts.caps_to_inherit); + if (capng_apply(CAPNG_SELECT_CAPS) != 0) + err(SETPRIV_EXIT_PRIVERR, _("apply capabilities")); + } + + execvp(argv[optind], argv + optind); + + err(EXIT_FAILURE, _("cannot execute: %s"), argv[optind]); +} -- 1.8.1.1 -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
