diff --git a/fs/file.c b/fs/file.c index 8434e0afecc7..c0b60961c672 100644 --- a/fs/file.c +++ b/fs/file.c @@ -694,8 +694,10 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) * If the requested range is greater than the current maximum, * we're closing everything so only copy all file descriptors * beneath the lowest file descriptor. + * If the caller requested all fds to be made cloexec copy all + * of the file descriptors since they still want to use them. */ - if (max_fd >= cur_max) + if (!(flags & CLOSE_RANGE_CLOEXEC) && (max_fd >= cur_max)) max_unshare_fds = fd; ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds); diff --git a/tools/testing/selftests/core/close_range_test.c b/tools/testing/selftests/core/close_range_test.c index 87e16d65d9d7..73eb29c916d1 100644 --- a/tools/testing/selftests/core/close_range_test.c +++ b/tools/testing/selftests/core/close_range_test.c @@ -17,7 +17,23 @@ #include "../clone3/clone3_selftests.h" #ifndef __NR_close_range -#define __NR_close_range -1 + #if defined __alpha__ + #define __NR_close_range 546 + #elif defined _MIPS_SIM + #if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */ + #define __NR_close_range (436 + 4000) + #endif + #if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */ + #define __NR_close_range (436 + 6000) + #endif + #if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */ + #define __NR_close_range (436 + 5000) + #endif + #elif defined __ia64__ + #define __NR_close_range (436 + 1024) + #else + #define __NR_close_range 436 + #endif #endif #ifndef CLOSE_RANGE_UNSHARE @@ -102,7 +118,7 @@ TEST(close_range_unshare) int i, ret, status; pid_t pid; int open_fds[101]; - struct clone_args args = { + struct __clone_args args = { .flags = CLONE_FILES, .exit_signal = SIGCHLD, }; @@ -191,7 +207,7 @@ TEST(close_range_unshare_capped) int i, ret, status; pid_t pid; int open_fds[101]; - struct clone_args args = { + struct __clone_args args = { .flags = CLONE_FILES, .exit_signal = SIGCHLD, }; @@ -241,7 +257,7 @@ TEST(close_range_cloexec) fd = open("/dev/null", O_RDONLY); ASSERT_GE(fd, 0) { if (errno == ENOENT) - XFAIL(return, "Skipping test since /dev/null does not exist"); + SKIP(return, "Skipping test since /dev/null does not exist"); } open_fds[i] = fd; @@ -250,9 +266,9 @@ TEST(close_range_cloexec) ret = sys_close_range(1000, 1000, CLOSE_RANGE_CLOEXEC); if (ret < 0) { if (errno == ENOSYS) - XFAIL(return, "close_range() syscall not supported"); + SKIP(return, "close_range() syscall not supported"); if (errno == EINVAL) - XFAIL(return, "close_range() doesn't support CLOSE_RANGE_CLOEXEC"); + SKIP(return, "close_range() doesn't support CLOSE_RANGE_CLOEXEC"); } /* Ensure the FD_CLOEXEC bit is set also with a resource limit in place. */ @@ -297,5 +313,258 @@ TEST(close_range_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, 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); + + 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); + + /* + * 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(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); +} + +/* + * 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_HARNESS_MAIN