diff options
Diffstat (limited to 'tools/testing/selftests/core')
| -rw-r--r-- | tools/testing/selftests/core/.gitignore | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/core/Makefile | 7 | ||||
| -rw-r--r-- | tools/testing/selftests/core/close_range_test.c | 666 | ||||
| -rw-r--r-- | tools/testing/selftests/core/unshare_test.c | 94 |
4 files changed, 769 insertions, 0 deletions
diff --git a/tools/testing/selftests/core/.gitignore b/tools/testing/selftests/core/.gitignore new file mode 100644 index 000000000000..7999361992aa --- /dev/null +++ b/tools/testing/selftests/core/.gitignore @@ -0,0 +1,2 @@ +close_range_test +unshare_test diff --git a/tools/testing/selftests/core/Makefile b/tools/testing/selftests/core/Makefile new file mode 100644 index 000000000000..8e99f87f5d7c --- /dev/null +++ b/tools/testing/selftests/core/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0-only +CFLAGS += -g $(KHDR_INCLUDES) + +TEST_GEN_PROGS := close_range_test unshare_test + +include ../lib.mk + diff --git a/tools/testing/selftests/core/close_range_test.c b/tools/testing/selftests/core/close_range_test.c new file mode 100644 index 000000000000..e0d9851fe1c9 --- /dev/null +++ b/tools/testing/selftests/core/close_range_test.c @@ -0,0 +1,666 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <linux/kernel.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syscall.h> +#include <unistd.h> +#include <sys/resource.h> +#include <linux/close_range.h> + +#include "../kselftest_harness.h" +#include "../clone3/clone3_selftests.h" + + +#ifndef F_LINUX_SPECIFIC_BASE +#define F_LINUX_SPECIFIC_BASE 1024 +#endif + +#ifndef F_DUPFD_QUERY +#define F_DUPFD_QUERY (F_LINUX_SPECIFIC_BASE + 3) +#endif + +#ifndef F_CREATED_QUERY +#define F_CREATED_QUERY (F_LINUX_SPECIFIC_BASE + 4) +#endif + +static inline int sys_close_range(unsigned int fd, unsigned int max_fd, + unsigned int flags) +{ + return syscall(__NR_close_range, fd, max_fd, flags); +} + +TEST(core_close_range) +{ + int i, ret; + int open_fds[101]; + + for (i = 0; i < ARRAY_SIZE(open_fds); i++) { + int fd; + + fd = open("/dev/null", O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, "Skipping test since /dev/null does not exist"); + } + + open_fds[i] = fd; + } + + EXPECT_EQ(-1, sys_close_range(open_fds[0], open_fds[100], -1)) { + if (errno == ENOSYS) + SKIP(return, "close_range() syscall not supported"); + } + + for (i = 0; i < 100; i++) { + ret = fcntl(open_fds[i], F_DUPFD_QUERY, open_fds[i + 1]); + if (ret < 0) { + EXPECT_EQ(errno, EINVAL); + } else { + EXPECT_EQ(ret, 0); + } + } + + EXPECT_EQ(0, sys_close_range(open_fds[0], open_fds[50], 0)); + + for (i = 0; i <= 50; i++) + EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL)); + + for (i = 51; i <= 100; i++) + EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1); + + /* create a couple of gaps */ + close(57); + close(78); + close(81); + close(82); + close(84); + close(90); + + EXPECT_EQ(0, sys_close_range(open_fds[51], open_fds[92], 0)); + + for (i = 51; i <= 92; i++) + EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL)); + + for (i = 93; i <= 100; i++) + EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1); + + /* test that the kernel caps and still closes all fds */ + EXPECT_EQ(0, sys_close_range(open_fds[93], open_fds[99], 0)); + + for (i = 93; i <= 99; i++) + EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL)); + + EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1); + + EXPECT_EQ(0, sys_close_range(open_fds[100], open_fds[100], 0)); + + EXPECT_EQ(-1, fcntl(open_fds[100], F_GETFL)); +} + +TEST(close_range_unshare) +{ + int i, ret, status; + pid_t pid; + int open_fds[101]; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + for (i = 0; i < ARRAY_SIZE(open_fds); i++) { + int fd; + + fd = open("/dev/null", O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, "Skipping test since /dev/null does not exist"); + } + + open_fds[i] = fd; + } + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = sys_close_range(open_fds[0], open_fds[50], + CLOSE_RANGE_UNSHARE); + if (ret) + exit(EXIT_FAILURE); + + for (i = 0; i <= 50; i++) + if (fcntl(open_fds[i], F_GETFL) != -1) + exit(EXIT_FAILURE); + + for (i = 51; i <= 100; i++) + if (fcntl(open_fds[i], F_GETFL) == -1) + exit(EXIT_FAILURE); + + /* create a couple of gaps */ + close(57); + close(78); + close(81); + close(82); + close(84); + close(90); + + ret = sys_close_range(open_fds[51], open_fds[92], + CLOSE_RANGE_UNSHARE); + if (ret) + exit(EXIT_FAILURE); + + for (i = 51; i <= 92; i++) + if (fcntl(open_fds[i], F_GETFL) != -1) + exit(EXIT_FAILURE); + + for (i = 93; i <= 100; i++) + if (fcntl(open_fds[i], F_GETFL) == -1) + exit(EXIT_FAILURE); + + /* test that the kernel caps and still closes all fds */ + ret = sys_close_range(open_fds[93], open_fds[99], + CLOSE_RANGE_UNSHARE); + if (ret) + exit(EXIT_FAILURE); + + for (i = 93; i <= 99; i++) + if (fcntl(open_fds[i], F_GETFL) != -1) + exit(EXIT_FAILURE); + + if (fcntl(open_fds[100], F_GETFL) == -1) + exit(EXIT_FAILURE); + + ret = sys_close_range(open_fds[100], open_fds[100], + CLOSE_RANGE_UNSHARE); + if (ret) + exit(EXIT_FAILURE); + + if (fcntl(open_fds[100], F_GETFL) != -1) + exit(EXIT_FAILURE); + + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(close_range_unshare_capped) +{ + int i, ret, status; + pid_t pid; + int open_fds[101]; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + for (i = 0; i < ARRAY_SIZE(open_fds); i++) { + int fd; + + fd = open("/dev/null", O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, "Skipping test since /dev/null does not exist"); + } + + open_fds[i] = fd; + } + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = sys_close_range(open_fds[0], UINT_MAX, + CLOSE_RANGE_UNSHARE); + if (ret) + exit(EXIT_FAILURE); + + for (i = 0; i <= 100; i++) + if (fcntl(open_fds[i], F_GETFL) != -1) + exit(EXIT_FAILURE); + + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(close_range_cloexec) +{ + int i, ret; + int open_fds[101]; + struct rlimit rlimit; + + for (i = 0; i < ARRAY_SIZE(open_fds); i++) { + int fd; + + fd = open("/dev/null", O_RDONLY); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, "Skipping test since /dev/null does not exist"); + } + + open_fds[i] = fd; + } + + ret = sys_close_range(1000, 1000, CLOSE_RANGE_CLOEXEC); + if (ret < 0) { + if (errno == ENOSYS) + SKIP(return, "close_range() syscall not supported"); + if (errno == EINVAL) + SKIP(return, "close_range() doesn't support CLOSE_RANGE_CLOEXEC"); + } + + /* Ensure the FD_CLOEXEC bit is set also with a resource limit in place. */ + ASSERT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit)); + rlimit.rlim_cur = 25; + ASSERT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit)); + + /* Set close-on-exec for two ranges: [0-50] and [75-100]. */ + ret = sys_close_range(open_fds[0], open_fds[50], CLOSE_RANGE_CLOEXEC); + ASSERT_EQ(0, ret); + ret = sys_close_range(open_fds[75], open_fds[100], CLOSE_RANGE_CLOEXEC); + ASSERT_EQ(0, ret); + + for (i = 0; i <= 50; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } + + for (i = 51; i <= 74; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + } + + for (i = 75; i <= 100; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } + + /* Test a common pattern. */ + ret = sys_close_range(3, UINT_MAX, CLOSE_RANGE_CLOEXEC); + for (i = 0; i <= 100; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } +} + +TEST(close_range_cloexec_unshare) +{ + int i, ret; + int open_fds[101]; + struct rlimit rlimit; + + for (i = 0; i < ARRAY_SIZE(open_fds); i++) { + int fd; + + fd = open("/dev/null", O_RDONLY); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, "Skipping test since /dev/null does not exist"); + } + + open_fds[i] = fd; + } + + ret = sys_close_range(1000, 1000, CLOSE_RANGE_CLOEXEC); + if (ret < 0) { + if (errno == ENOSYS) + SKIP(return, "close_range() syscall not supported"); + if (errno == EINVAL) + SKIP(return, "close_range() doesn't support CLOSE_RANGE_CLOEXEC"); + } + + /* Ensure the FD_CLOEXEC bit is set also with a resource limit in place. */ + ASSERT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit)); + rlimit.rlim_cur = 25; + ASSERT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit)); + + /* Set close-on-exec for two ranges: [0-50] and [75-100]. */ + ret = sys_close_range(open_fds[0], open_fds[50], + CLOSE_RANGE_CLOEXEC | CLOSE_RANGE_UNSHARE); + ASSERT_EQ(0, ret); + ret = sys_close_range(open_fds[75], open_fds[100], + CLOSE_RANGE_CLOEXEC | CLOSE_RANGE_UNSHARE); + ASSERT_EQ(0, ret); + + for (i = 0; i <= 50; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } + + for (i = 51; i <= 74; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + } + + for (i = 75; i <= 100; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } + + /* Test a common pattern. */ + ret = sys_close_range(3, UINT_MAX, + CLOSE_RANGE_CLOEXEC | CLOSE_RANGE_UNSHARE); + for (i = 0; i <= 100; i++) { + int flags = fcntl(open_fds[i], F_GETFD); + + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + } +} + +/* + * Regression test for syzbot+96cfd2b22b3213646a93@syzkaller.appspotmail.com + */ +TEST(close_range_cloexec_syzbot) +{ + int fd1, fd2, fd3, fd4, flags, ret, status; + pid_t pid; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + /* Create a huge gap in the fd table. */ + fd1 = open("/dev/null", O_RDWR); + EXPECT_GT(fd1, 0); + + fd2 = dup2(fd1, 1000); + EXPECT_GT(fd2, 0); + + flags = fcntl(fd1, F_DUPFD_QUERY, fd2); + if (flags < 0) { + EXPECT_EQ(errno, EINVAL); + } else { + EXPECT_EQ(flags, 1); + } + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = sys_close_range(3, ~0U, CLOSE_RANGE_CLOEXEC); + if (ret) + exit(EXIT_FAILURE); + + /* + * We now have a private file descriptor table and all + * our open fds should still be open but made + * close-on-exec. + */ + flags = fcntl(fd1, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + flags = fcntl(fd2, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + fd3 = dup2(fd1, 42); + EXPECT_GT(fd3, 0); + + flags = fcntl(fd1, F_DUPFD_QUERY, fd3); + if (flags < 0) { + EXPECT_EQ(errno, EINVAL); + } else { + EXPECT_EQ(flags, 1); + } + + + + /* + * Duplicating the file descriptor must remove the + * FD_CLOEXEC flag. + */ + flags = fcntl(fd3, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + + /* + * We had a shared file descriptor table before along with requesting + * close-on-exec so the original fds must not be close-on-exec. + */ + flags = fcntl(fd1, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + flags = fcntl(fd2, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + fd3 = dup2(fd1, 42); + EXPECT_GT(fd3, 0); + + flags = fcntl(fd1, F_DUPFD_QUERY, fd3); + if (flags < 0) { + EXPECT_EQ(errno, EINVAL); + } else { + EXPECT_EQ(flags, 1); + } + + fd4 = open("/dev/null", O_RDWR); + EXPECT_GT(fd4, 0); + + /* Same inode, different file pointers. */ + flags = fcntl(fd1, F_DUPFD_QUERY, fd4); + if (flags < 0) { + EXPECT_EQ(errno, EINVAL); + } else { + EXPECT_EQ(flags, 0); + } + + flags = fcntl(fd3, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + EXPECT_EQ(close(fd1), 0); + EXPECT_EQ(close(fd2), 0); + EXPECT_EQ(close(fd3), 0); + EXPECT_EQ(close(fd4), 0); +} + +/* + * Regression test for syzbot+96cfd2b22b3213646a93@syzkaller.appspotmail.com + */ +TEST(close_range_cloexec_unshare_syzbot) +{ + int i, fd1, fd2, fd3, flags, ret, status; + pid_t pid; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + /* + * Create a huge gap in the fd table. When we now call + * CLOSE_RANGE_UNSHARE with a shared fd table and and with ~0U as upper + * bound the kernel will only copy up to fd1 file descriptors into the + * new fd table. If the kernel is buggy and doesn't handle + * CLOSE_RANGE_CLOEXEC correctly it will not have copied all file + * descriptors and we will oops! + * + * On a buggy kernel this should immediately oops. But let's loop just + * to be sure. + */ + fd1 = open("/dev/null", O_RDWR); + EXPECT_GT(fd1, 0); + + fd2 = dup2(fd1, 1000); + EXPECT_GT(fd2, 0); + + for (i = 0; i < 100; i++) { + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = sys_close_range(3, ~0U, CLOSE_RANGE_UNSHARE | + CLOSE_RANGE_CLOEXEC); + if (ret) + exit(EXIT_FAILURE); + + /* + * We now have a private file descriptor table and all + * our open fds should still be open but made + * close-on-exec. + */ + flags = fcntl(fd1, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + flags = fcntl(fd2, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC); + + fd3 = dup2(fd1, 42); + EXPECT_GT(fd3, 0); + + /* + * Duplicating the file descriptor must remove the + * FD_CLOEXEC flag. + */ + flags = fcntl(fd3, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + EXPECT_EQ(close(fd1), 0); + EXPECT_EQ(close(fd2), 0); + EXPECT_EQ(close(fd3), 0); + + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + } + + /* + * We created a private file descriptor table before along with + * requesting close-on-exec so the original fds must not be + * close-on-exec. + */ + flags = fcntl(fd1, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + flags = fcntl(fd2, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + fd3 = dup2(fd1, 42); + EXPECT_GT(fd3, 0); + + flags = fcntl(fd3, F_GETFD); + EXPECT_GT(flags, -1); + EXPECT_EQ(flags & FD_CLOEXEC, 0); + + EXPECT_EQ(close(fd1), 0); + EXPECT_EQ(close(fd2), 0); + EXPECT_EQ(close(fd3), 0); +} + +TEST(close_range_bitmap_corruption) +{ + pid_t pid; + int status; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + /* get the first 128 descriptors open */ + for (int i = 2; i < 128; i++) + EXPECT_GE(dup2(0, i), 0); + + /* get descriptor table shared */ + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + /* unshare and truncate descriptor table down to 64 */ + if (sys_close_range(64, ~0U, CLOSE_RANGE_UNSHARE)) + exit(EXIT_FAILURE); + + ASSERT_EQ(fcntl(64, F_GETFD), -1); + /* ... and verify that the range 64..127 is not + stuck "fully used" according to secondary bitmap */ + EXPECT_EQ(dup(0), 64) + exit(EXIT_FAILURE); + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(fcntl_created) +{ + for (int i = 0; i < 101; i++) { + int fd; + char path[PATH_MAX]; + + fd = open("/dev/null", O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0) { + if (errno == ENOENT) + SKIP(return, + "Skipping test since /dev/null does not exist"); + } + + /* We didn't create "/dev/null". */ + EXPECT_EQ(fcntl(fd, F_CREATED_QUERY, 0), 0); + close(fd); + + sprintf(path, "aaaa_%d", i); + fd = open(path, O_CREAT | O_RDONLY | O_CLOEXEC, 0600); + ASSERT_GE(fd, 0); + + /* We created "aaaa_%d". */ + EXPECT_EQ(fcntl(fd, F_CREATED_QUERY, 0), 1); + close(fd); + + fd = open(path, O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0); + + /* We're opening it again, so no positive creation check. */ + EXPECT_EQ(fcntl(fd, F_CREATED_QUERY, 0), 0); + close(fd); + unlink(path); + } +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/core/unshare_test.c b/tools/testing/selftests/core/unshare_test.c new file mode 100644 index 000000000000..7fec9dfb1b0e --- /dev/null +++ b/tools/testing/selftests/core/unshare_test.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <linux/kernel.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syscall.h> +#include <unistd.h> +#include <sys/resource.h> +#include <linux/close_range.h> + +#include "../kselftest_harness.h" +#include "../clone3/clone3_selftests.h" + +TEST(unshare_EMFILE) +{ + pid_t pid; + int status; + struct __clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + int fd; + ssize_t n, n2; + static char buf[512], buf2[512]; + struct rlimit rlimit; + int nr_open; + + fd = open("/proc/sys/fs/nr_open", O_RDWR); + ASSERT_GE(fd, 0); + + n = read(fd, buf, sizeof(buf)); + ASSERT_GT(n, 0); + ASSERT_EQ(buf[n - 1], '\n'); + + ASSERT_EQ(sscanf(buf, "%d", &nr_open), 1); + + ASSERT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit)); + + /* bump fs.nr_open */ + n2 = sprintf(buf2, "%d\n", nr_open + 1024); + lseek(fd, 0, SEEK_SET); + write(fd, buf2, n2); + + /* bump ulimit -n */ + rlimit.rlim_cur = nr_open + 1024; + rlimit.rlim_max = nr_open + 1024; + EXPECT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit)) { + lseek(fd, 0, SEEK_SET); + write(fd, buf, n); + exit(EXIT_FAILURE); + } + + /* get a descriptor past the old fs.nr_open */ + EXPECT_GE(dup2(2, nr_open + 64), 0) { + lseek(fd, 0, SEEK_SET); + write(fd, buf, n); + exit(EXIT_FAILURE); + } + + /* get descriptor table shared */ + pid = sys_clone3(&args, sizeof(args)); + EXPECT_GE(pid, 0) { + lseek(fd, 0, SEEK_SET); + write(fd, buf, n); + exit(EXIT_FAILURE); + } + + if (pid == 0) { + int err; + + /* restore fs.nr_open */ + lseek(fd, 0, SEEK_SET); + write(fd, buf, n); + /* ... and now unshare(CLONE_FILES) must fail with EMFILE */ + err = unshare(CLONE_FILES); + EXPECT_EQ(err, -1) + exit(EXIT_FAILURE); + EXPECT_EQ(errno, EMFILE) + exit(EXIT_FAILURE); + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST_HARNESS_MAIN |