selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC
Tests to verify MFD_NOEXEC, MFD_EXEC and vm.memfd_noexec sysctl. Link: https://lkml.kernel.org/r/20221215001205.51969-6-jeffxu@google.com Signed-off-by: Jeff Xu <jeffxu@google.com> Co-developed-by: Daniel Verkamp <dverkamp@chromium.org> Signed-off-by: Daniel Verkamp <dverkamp@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Jorge Lucangeli Obes <jorgelo@chromium.org> Cc: kernel test robot <lkp@intel.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jeff Xu
Andrew Morton
Родитель
c4f75bc8bd
Коммит
11f75a0144
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@ -22,6 +22,7 @@
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#include <linux/falloc.h>
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#include <fcntl.h>
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#include <linux/memfd.h>
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#include <linux/types.h>
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#include <sched.h>
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#include <stdio.h>
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#include <stdlib.h>
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@ -30,6 +30,14 @@
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#define F_SEAL_EXEC 0x0020
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#define F_WX_SEALS (F_SEAL_SHRINK | \
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F_SEAL_GROW | \
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F_SEAL_WRITE | \
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F_SEAL_FUTURE_WRITE | \
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F_SEAL_EXEC)
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#define MFD_NOEXEC_SEAL 0x0008U
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/*
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* Default is not to test hugetlbfs
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*/
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@ -80,6 +88,37 @@ static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
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return fd;
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}
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static void sysctl_assert_write(const char *val)
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{
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int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
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if (fd < 0) {
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printf("open sysctl failed\n");
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abort();
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}
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if (write(fd, val, strlen(val)) < 0) {
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printf("write sysctl failed\n");
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abort();
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}
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}
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static void sysctl_fail_write(const char *val)
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{
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int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
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if (fd < 0) {
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printf("open sysctl failed\n");
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abort();
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}
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if (write(fd, val, strlen(val)) >= 0) {
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printf("write sysctl %s succeeded, but failure expected\n",
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val);
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abort();
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}
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}
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static int mfd_assert_reopen_fd(int fd_in)
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{
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int fd;
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@ -758,6 +797,9 @@ static void test_create(void)
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mfd_fail_new("", ~0);
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mfd_fail_new("", 0x80000000U);
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/* verify EXEC and NOEXEC_SEAL can't both be set */
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mfd_fail_new("", MFD_EXEC | MFD_NOEXEC_SEAL);
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/* verify MFD_CLOEXEC is allowed */
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fd = mfd_assert_new("", 0, MFD_CLOEXEC);
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close(fd);
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@ -969,20 +1011,21 @@ static void test_seal_resize(void)
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/*
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* Test SEAL_EXEC
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* Test that chmod() cannot change x bits after sealing
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* Test fd is created with exec and allow sealing.
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* chmod() cannot change x bits after sealing.
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*/
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static void test_seal_exec(void)
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static void test_exec_seal(void)
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{
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int fd;
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printf("%s SEAL-EXEC\n", memfd_str);
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printf("%s Apply SEAL_EXEC\n", memfd_str);
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fd = mfd_assert_new("kern_memfd_seal_exec",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING);
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MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
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mfd_assert_mode(fd, 0777);
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mfd_assert_chmod(fd, 0644);
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mfd_assert_has_seals(fd, 0);
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@ -996,8 +1039,179 @@ static void test_seal_exec(void)
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mfd_fail_chmod(fd, 0700);
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mfd_fail_chmod(fd, 0100);
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mfd_assert_chmod(fd, 0666);
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mfd_assert_write(fd);
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close(fd);
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printf("%s Apply ALL_SEALS\n", memfd_str);
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fd = mfd_assert_new("kern_memfd_seal_exec",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
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mfd_assert_mode(fd, 0777);
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mfd_assert_chmod(fd, 0700);
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mfd_assert_has_seals(fd, 0);
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mfd_assert_add_seals(fd, F_SEAL_EXEC);
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mfd_assert_has_seals(fd, F_WX_SEALS);
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mfd_fail_chmod(fd, 0711);
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mfd_fail_chmod(fd, 0600);
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mfd_fail_write(fd);
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close(fd);
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}
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/*
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* Test EXEC_NO_SEAL
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* Test fd is created with exec and not allow sealing.
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*/
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static void test_exec_no_seal(void)
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{
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int fd;
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printf("%s EXEC_NO_SEAL\n", memfd_str);
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/* Create with EXEC but without ALLOW_SEALING */
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fd = mfd_assert_new("kern_memfd_exec_no_sealing",
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mfd_def_size,
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MFD_CLOEXEC | MFD_EXEC);
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mfd_assert_mode(fd, 0777);
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mfd_assert_has_seals(fd, F_SEAL_SEAL);
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mfd_assert_chmod(fd, 0666);
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close(fd);
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}
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/*
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* Test memfd_create with MFD_NOEXEC flag
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*/
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static void test_noexec_seal(void)
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{
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int fd;
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printf("%s NOEXEC_SEAL\n", memfd_str);
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/* Create with NOEXEC and ALLOW_SEALING */
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fd = mfd_assert_new("kern_memfd_noexec",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
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mfd_assert_mode(fd, 0666);
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mfd_assert_has_seals(fd, F_SEAL_EXEC);
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mfd_fail_chmod(fd, 0777);
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close(fd);
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/* Create with NOEXEC but without ALLOW_SEALING */
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fd = mfd_assert_new("kern_memfd_noexec",
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mfd_def_size,
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MFD_CLOEXEC | MFD_NOEXEC_SEAL);
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mfd_assert_mode(fd, 0666);
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mfd_assert_has_seals(fd, F_SEAL_EXEC);
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mfd_fail_chmod(fd, 0777);
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close(fd);
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}
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static void test_sysctl_child(void)
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{
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int fd;
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printf("%s sysctl 0\n", memfd_str);
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sysctl_assert_write("0");
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fd = mfd_assert_new("kern_memfd_sysctl_0",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING);
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mfd_assert_mode(fd, 0777);
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mfd_assert_has_seals(fd, 0);
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mfd_assert_chmod(fd, 0644);
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close(fd);
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printf("%s sysctl 1\n", memfd_str);
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sysctl_assert_write("1");
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fd = mfd_assert_new("kern_memfd_sysctl_1",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING);
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mfd_assert_mode(fd, 0666);
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mfd_assert_has_seals(fd, F_SEAL_EXEC);
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mfd_fail_chmod(fd, 0777);
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sysctl_fail_write("0");
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close(fd);
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printf("%s sysctl 2\n", memfd_str);
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sysctl_assert_write("2");
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mfd_fail_new("kern_memfd_sysctl_2",
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MFD_CLOEXEC | MFD_ALLOW_SEALING);
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sysctl_fail_write("0");
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sysctl_fail_write("1");
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}
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static int newpid_thread_fn(void *arg)
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{
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test_sysctl_child();
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return 0;
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}
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static void test_sysctl_child2(void)
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{
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int fd;
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sysctl_fail_write("0");
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fd = mfd_assert_new("kern_memfd_sysctl_1",
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mfd_def_size,
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MFD_CLOEXEC | MFD_ALLOW_SEALING);
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mfd_assert_mode(fd, 0666);
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mfd_assert_has_seals(fd, F_SEAL_EXEC);
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mfd_fail_chmod(fd, 0777);
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close(fd);
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}
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static int newpid_thread_fn2(void *arg)
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{
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test_sysctl_child2();
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return 0;
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}
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static pid_t spawn_newpid_thread(unsigned int flags, int (*fn)(void *))
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{
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uint8_t *stack;
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pid_t pid;
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stack = malloc(STACK_SIZE);
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if (!stack) {
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printf("malloc(STACK_SIZE) failed: %m\n");
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abort();
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}
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pid = clone(fn,
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stack + STACK_SIZE,
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SIGCHLD | flags,
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NULL);
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if (pid < 0) {
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printf("clone() failed: %m\n");
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abort();
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}
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return pid;
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}
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static void join_newpid_thread(pid_t pid)
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{
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waitpid(pid, NULL, 0);
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}
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/*
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* Test sysctl
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* A very basic sealing test to see whether setting/retrieving seals works.
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*/
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static void test_sysctl(void)
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{
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int pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn);
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join_newpid_thread(pid);
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printf("%s child ns\n", memfd_str);
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sysctl_assert_write("1");
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pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
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join_newpid_thread(pid);
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}
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/*
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@ -1173,13 +1387,15 @@ int main(int argc, char **argv)
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test_create();
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test_basic();
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test_exec_seal();
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test_exec_no_seal();
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test_noexec_seal();
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test_seal_write();
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test_seal_future_write();
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test_seal_shrink();
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test_seal_grow();
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test_seal_resize();
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test_seal_exec();
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test_share_dup("SHARE-DUP", "");
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test_share_mmap("SHARE-MMAP", "");
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@ -1195,6 +1411,8 @@ int main(int argc, char **argv)
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test_share_fork("SHARE-FORK", SHARED_FT_STR);
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join_idle_thread(pid);
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test_sysctl();
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printf("memfd: DONE\n");
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return 0;
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