diff options
Diffstat (limited to 'tools/testing/selftests/landlock/fs_test.c')
| -rw-r--r-- | tools/testing/selftests/landlock/fs_test.c | 532 |
1 files changed, 521 insertions, 11 deletions
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 27744524df..7d063c652b 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -8,22 +8,35 @@ */ #define _GNU_SOURCE +#include <asm/termbits.h> #include <fcntl.h> #include <libgen.h> +#include <linux/fiemap.h> #include <linux/landlock.h> #include <linux/magic.h> #include <sched.h> +#include <stddef.h> #include <stdio.h> #include <string.h> #include <sys/capability.h> +#include <sys/ioctl.h> #include <sys/mount.h> #include <sys/prctl.h> #include <sys/sendfile.h> +#include <sys/socket.h> #include <sys/stat.h> #include <sys/sysmacros.h> +#include <sys/un.h> #include <sys/vfs.h> #include <unistd.h> +/* + * Intentionally included last to work around header conflict. + * See https://sourceware.org/glibc/wiki/Synchronizing_Headers. + */ +#include <linux/fs.h> +#include <linux/mount.h> + #include "common.h" #ifndef renameat2 @@ -35,6 +48,13 @@ int renameat2(int olddirfd, const char *oldpath, int newdirfd, } #endif +#ifndef open_tree +int open_tree(int dfd, const char *filename, unsigned int flags) +{ + return syscall(__NR_open_tree, dfd, filename, flags); +} +#endif + #ifndef RENAME_EXCHANGE #define RENAME_EXCHANGE (1 << 1) #endif @@ -536,9 +556,10 @@ TEST_F_FORK(layout1, inval) LANDLOCK_ACCESS_FS_EXECUTE | \ LANDLOCK_ACCESS_FS_WRITE_FILE | \ LANDLOCK_ACCESS_FS_READ_FILE | \ - LANDLOCK_ACCESS_FS_TRUNCATE) + LANDLOCK_ACCESS_FS_TRUNCATE | \ + LANDLOCK_ACCESS_FS_IOCTL_DEV) -#define ACCESS_LAST LANDLOCK_ACCESS_FS_TRUNCATE +#define ACCESS_LAST LANDLOCK_ACCESS_FS_IOCTL_DEV #define ACCESS_ALL ( \ ACCESS_FILE | \ @@ -743,6 +764,9 @@ static int create_ruleset(struct __test_metadata *const _metadata, } for (i = 0; rules[i].path; i++) { + if (!rules[i].access) + continue; + add_path_beneath(_metadata, ruleset_fd, rules[i].access, rules[i].path); } @@ -2384,6 +2408,43 @@ TEST_F_FORK(layout1, refer_denied_by_default4) layer_dir_s1d1_refer); } +/* + * Tests walking through a denied root mount. + */ +TEST_F_FORK(layout1, refer_mount_root_deny) +{ + const struct landlock_ruleset_attr ruleset_attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_MAKE_DIR, + }; + int root_fd, ruleset_fd; + + /* Creates a mount object from a non-mount point. */ + set_cap(_metadata, CAP_SYS_ADMIN); + root_fd = + open_tree(AT_FDCWD, dir_s1d1, + AT_EMPTY_PATH | OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC); + clear_cap(_metadata, CAP_SYS_ADMIN); + ASSERT_LE(0, root_fd); + + ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)); + ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)); + EXPECT_EQ(0, close(ruleset_fd)); + + /* Link denied by Landlock: EACCES. */ + EXPECT_EQ(-1, linkat(root_fd, ".", root_fd, "does_not_exist", 0)); + EXPECT_EQ(EACCES, errno); + + /* renameat2() always returns EBUSY. */ + EXPECT_EQ(-1, renameat2(root_fd, ".", root_fd, "does_not_exist", 0)); + EXPECT_EQ(EBUSY, errno); + + EXPECT_EQ(0, close(root_fd)); +} + TEST_F_FORK(layout1, reparent_link) { const struct rule layer1[] = { @@ -3451,7 +3512,7 @@ TEST_F_FORK(layout1, truncate_unhandled) LANDLOCK_ACCESS_FS_WRITE_FILE; int ruleset_fd; - /* Enable Landlock. */ + /* Enables Landlock. */ ruleset_fd = create_ruleset(_metadata, handled, rules); ASSERT_LE(0, ruleset_fd); @@ -3534,7 +3595,7 @@ TEST_F_FORK(layout1, truncate) LANDLOCK_ACCESS_FS_TRUNCATE; int ruleset_fd; - /* Enable Landlock. */ + /* Enables Landlock. */ ruleset_fd = create_ruleset(_metadata, handled, rules); ASSERT_LE(0, ruleset_fd); @@ -3760,7 +3821,7 @@ TEST_F_FORK(ftruncate, open_and_ftruncate) }; int fd, ruleset_fd; - /* Enable Landlock. */ + /* Enables Landlock. */ ruleset_fd = create_ruleset(_metadata, variant->handled, rules); ASSERT_LE(0, ruleset_fd); enforce_ruleset(_metadata, ruleset_fd); @@ -3837,20 +3898,469 @@ TEST_F_FORK(ftruncate, open_and_ftruncate_in_different_processes) ASSERT_EQ(0, close(socket_fds[1])); } -TEST(memfd_ftruncate) +/* Invokes the FS_IOC_GETFLAGS IOCTL and returns its errno or 0. */ +static int test_fs_ioc_getflags_ioctl(int fd) { - int fd; + uint32_t flags; + + if (ioctl(fd, FS_IOC_GETFLAGS, &flags) < 0) + return errno; + return 0; +} + +TEST(memfd_ftruncate_and_ioctl) +{ + const struct landlock_ruleset_attr attr = { + .handled_access_fs = ACCESS_ALL, + }; + int ruleset_fd, fd, i; + + /* + * We exercise the same test both with and without Landlock enabled, to + * ensure that it behaves the same in both cases. + */ + for (i = 0; i < 2; i++) { + /* Creates a new memfd. */ + fd = memfd_create("name", MFD_CLOEXEC); + ASSERT_LE(0, fd); + + /* + * Checks that operations associated with the opened file + * (ftruncate, ioctl) are permitted on file descriptors that are + * created in ways other than open(2). + */ + EXPECT_EQ(0, test_ftruncate(fd)); + EXPECT_EQ(0, test_fs_ioc_getflags_ioctl(fd)); + + ASSERT_EQ(0, close(fd)); + + /* Enables Landlock. */ + ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + } +} + +static int test_fionread_ioctl(int fd) +{ + size_t sz = 0; + + if (ioctl(fd, FIONREAD, &sz) < 0 && errno == EACCES) + return errno; + return 0; +} + +TEST_F_FORK(layout1, o_path_ftruncate_and_ioctl) +{ + const struct landlock_ruleset_attr attr = { + .handled_access_fs = ACCESS_ALL, + }; + int ruleset_fd, fd; + + /* + * Checks that for files opened with O_PATH, both ioctl(2) and + * ftruncate(2) yield EBADF, as it is documented in open(2) for the + * O_PATH flag. + */ + fd = open(dir_s1d1, O_PATH | O_CLOEXEC); + ASSERT_LE(0, fd); + + EXPECT_EQ(EBADF, test_ftruncate(fd)); + EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd)); + + ASSERT_EQ(0, close(fd)); + + /* Enables Landlock. */ + ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* + * Checks that after enabling Landlock, + * - the file can still be opened with O_PATH + * - both ioctl and truncate still yield EBADF (not EACCES). + */ + fd = open(dir_s1d1, O_PATH | O_CLOEXEC); + ASSERT_LE(0, fd); + + EXPECT_EQ(EBADF, test_ftruncate(fd)); + EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd)); + + ASSERT_EQ(0, close(fd)); +} + +/* + * ioctl_error - generically call the given ioctl with a pointer to a + * sufficiently large zeroed-out memory region. + * + * Returns the IOCTLs error, or 0. + */ +static int ioctl_error(struct __test_metadata *const _metadata, int fd, + unsigned int cmd) +{ + char buf[128]; /* sufficiently large */ + int res, stdinbak_fd; + + /* + * Depending on the IOCTL command, parts of the zeroed-out buffer might + * be interpreted as file descriptor numbers. We do not want to + * accidentally operate on file descriptor 0 (stdin), so we temporarily + * move stdin to a different FD and close FD 0 for the IOCTL call. + */ + stdinbak_fd = dup(0); + ASSERT_LT(0, stdinbak_fd); + ASSERT_EQ(0, close(0)); + + /* Invokes the IOCTL with a zeroed-out buffer. */ + bzero(&buf, sizeof(buf)); + res = ioctl(fd, cmd, &buf); + + /* Restores the old FD 0 and closes the backup FD. */ + ASSERT_EQ(0, dup2(stdinbak_fd, 0)); + ASSERT_EQ(0, close(stdinbak_fd)); + + if (res < 0) + return errno; + + return 0; +} + +/* Define some linux/falloc.h IOCTL commands which are not available in uapi headers. */ +struct space_resv { + __s16 l_type; + __s16 l_whence; + __s64 l_start; + __s64 l_len; /* len == 0 means until end of file */ + __s32 l_sysid; + __u32 l_pid; + __s32 l_pad[4]; /* reserved area */ +}; + +#define FS_IOC_RESVSP _IOW('X', 40, struct space_resv) +#define FS_IOC_UNRESVSP _IOW('X', 41, struct space_resv) +#define FS_IOC_RESVSP64 _IOW('X', 42, struct space_resv) +#define FS_IOC_UNRESVSP64 _IOW('X', 43, struct space_resv) +#define FS_IOC_ZERO_RANGE _IOW('X', 57, struct space_resv) + +/* + * Tests a series of blanket-permitted and denied IOCTLs. + */ +TEST_F_FORK(layout1, blanket_permitted_ioctls) +{ + const struct landlock_ruleset_attr attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV, + }; + int ruleset_fd, fd; + + /* Enables Landlock. */ + ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); - fd = memfd_create("name", MFD_CLOEXEC); + fd = open("/dev/null", O_RDWR | O_CLOEXEC); ASSERT_LE(0, fd); /* - * Checks that ftruncate is permitted on file descriptors that are - * created in ways other than open(2). + * Checks permitted commands. + * These ones may return errors, but should not be blocked by Landlock. */ - EXPECT_EQ(0, test_ftruncate(fd)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOCLEX)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIONCLEX)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIONBIO)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOASYNC)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIOQSIZE)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIFREEZE)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FITHAW)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_FIEMAP)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIGETBSZ)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FICLONE)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FICLONERANGE)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FIDEDUPERANGE)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFSUUID)); + EXPECT_NE(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFSSYSFSPATH)); + + /* + * Checks blocked commands. + * A call to a blocked IOCTL command always returns EACCES. + */ + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FIONREAD)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_GETFLAGS)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_SETFLAGS)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_FSGETXATTR)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_FSSETXATTR)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FIBMAP)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_RESVSP)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_RESVSP64)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_UNRESVSP)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_UNRESVSP64)); + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, FS_IOC_ZERO_RANGE)); + + /* Default case is also blocked. */ + EXPECT_EQ(EACCES, ioctl_error(_metadata, fd, 0xc00ffeee)); + + ASSERT_EQ(0, close(fd)); +} + +/* + * Named pipes are not governed by the LANDLOCK_ACCESS_FS_IOCTL_DEV right, + * because they are not character or block devices. + */ +TEST_F_FORK(layout1, named_pipe_ioctl) +{ + pid_t child_pid; + int fd, ruleset_fd; + const char *const path = file1_s1d1; + const struct landlock_ruleset_attr attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV, + }; + + ASSERT_EQ(0, unlink(path)); + ASSERT_EQ(0, mkfifo(path, 0600)); + + /* Enables Landlock. */ + ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* The child process opens the pipe for writing. */ + child_pid = fork(); + ASSERT_NE(-1, child_pid); + if (child_pid == 0) { + fd = open(path, O_WRONLY); + close(fd); + exit(0); + } + + fd = open(path, O_RDONLY); + ASSERT_LE(0, fd); + + /* FIONREAD is implemented by pipefifo_fops. */ + EXPECT_EQ(0, test_fionread_ioctl(fd)); ASSERT_EQ(0, close(fd)); + ASSERT_EQ(0, unlink(path)); + + ASSERT_EQ(child_pid, waitpid(child_pid, NULL, 0)); +} + +/* For named UNIX domain sockets, no IOCTL restrictions apply. */ +TEST_F_FORK(layout1, named_unix_domain_socket_ioctl) +{ + const char *const path = file1_s1d1; + int srv_fd, cli_fd, ruleset_fd; + socklen_t size; + struct sockaddr_un srv_un, cli_un; + const struct landlock_ruleset_attr attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV, + }; + + /* Sets up a server */ + srv_un.sun_family = AF_UNIX; + strncpy(srv_un.sun_path, path, sizeof(srv_un.sun_path)); + + ASSERT_EQ(0, unlink(path)); + srv_fd = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_LE(0, srv_fd); + + size = offsetof(struct sockaddr_un, sun_path) + strlen(srv_un.sun_path); + ASSERT_EQ(0, bind(srv_fd, (struct sockaddr *)&srv_un, size)); + ASSERT_EQ(0, listen(srv_fd, 10 /* qlen */)); + + /* Enables Landlock. */ + ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* Sets up a client connection to it */ + cli_un.sun_family = AF_UNIX; + cli_fd = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_LE(0, cli_fd); + + size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path); + ASSERT_EQ(0, bind(cli_fd, (struct sockaddr *)&cli_un, size)); + + bzero(&cli_un, sizeof(cli_un)); + cli_un.sun_family = AF_UNIX; + strncpy(cli_un.sun_path, path, sizeof(cli_un.sun_path)); + size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path); + + ASSERT_EQ(0, connect(cli_fd, (struct sockaddr *)&cli_un, size)); + + /* FIONREAD and other IOCTLs should not be forbidden. */ + EXPECT_EQ(0, test_fionread_ioctl(cli_fd)); + + ASSERT_EQ(0, close(cli_fd)); +} + +/* clang-format off */ +FIXTURE(ioctl) {}; + +FIXTURE_SETUP(ioctl) {}; + +FIXTURE_TEARDOWN(ioctl) {}; +/* clang-format on */ + +FIXTURE_VARIANT(ioctl) +{ + const __u64 handled; + const __u64 allowed; + const mode_t open_mode; + /* + * FIONREAD is used as a characteristic device-specific IOCTL command. + * It is implemented in fs/ioctl.c for regular files, + * but we do not blanket-permit it for devices. + */ + const int expected_fionread_result; +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(ioctl, handled_i_allowed_none) { + /* clang-format on */ + .handled = LANDLOCK_ACCESS_FS_IOCTL_DEV, + .allowed = 0, + .open_mode = O_RDWR, + .expected_fionread_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(ioctl, handled_i_allowed_i) { + /* clang-format on */ + .handled = LANDLOCK_ACCESS_FS_IOCTL_DEV, + .allowed = LANDLOCK_ACCESS_FS_IOCTL_DEV, + .open_mode = O_RDWR, + .expected_fionread_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(ioctl, unhandled) { + /* clang-format on */ + .handled = LANDLOCK_ACCESS_FS_EXECUTE, + .allowed = LANDLOCK_ACCESS_FS_EXECUTE, + .open_mode = O_RDWR, + .expected_fionread_result = 0, +}; + +TEST_F_FORK(ioctl, handle_dir_access_file) +{ + const int flag = 0; + const struct rule rules[] = { + { + .path = "/dev", + .access = variant->allowed, + }, + {}, + }; + int file_fd, ruleset_fd; + + /* Enables Landlock. */ + ruleset_fd = create_ruleset(_metadata, variant->handled, rules); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + file_fd = open("/dev/zero", variant->open_mode); + ASSERT_LE(0, file_fd); + + /* Checks that IOCTL commands return the expected errors. */ + EXPECT_EQ(variant->expected_fionread_result, + test_fionread_ioctl(file_fd)); + + /* Checks that unrestrictable commands are unrestricted. */ + EXPECT_EQ(0, ioctl(file_fd, FIOCLEX)); + EXPECT_EQ(0, ioctl(file_fd, FIONCLEX)); + EXPECT_EQ(0, ioctl(file_fd, FIONBIO, &flag)); + EXPECT_EQ(0, ioctl(file_fd, FIOASYNC, &flag)); + EXPECT_EQ(0, ioctl(file_fd, FIGETBSZ, &flag)); + + ASSERT_EQ(0, close(file_fd)); +} + +TEST_F_FORK(ioctl, handle_dir_access_dir) +{ + const int flag = 0; + const struct rule rules[] = { + { + .path = "/dev", + .access = variant->allowed, + }, + {}, + }; + int dir_fd, ruleset_fd; + + /* Enables Landlock. */ + ruleset_fd = create_ruleset(_metadata, variant->handled, rules); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* + * Ignore variant->open_mode for this test, as we intend to open a + * directory. If the directory can not be opened, the variant is + * infeasible to test with an opened directory. + */ + dir_fd = open("/dev", O_RDONLY); + if (dir_fd < 0) + return; + + /* + * Checks that IOCTL commands return the expected errors. + * We do not use the expected values from the fixture here. + * + * When using IOCTL on a directory, no Landlock restrictions apply. + */ + EXPECT_EQ(0, test_fionread_ioctl(dir_fd)); + + /* Checks that unrestrictable commands are unrestricted. */ + EXPECT_EQ(0, ioctl(dir_fd, FIOCLEX)); + EXPECT_EQ(0, ioctl(dir_fd, FIONCLEX)); + EXPECT_EQ(0, ioctl(dir_fd, FIONBIO, &flag)); + EXPECT_EQ(0, ioctl(dir_fd, FIOASYNC, &flag)); + EXPECT_EQ(0, ioctl(dir_fd, FIGETBSZ, &flag)); + + ASSERT_EQ(0, close(dir_fd)); +} + +TEST_F_FORK(ioctl, handle_file_access_file) +{ + const int flag = 0; + const struct rule rules[] = { + { + .path = "/dev/zero", + .access = variant->allowed, + }, + {}, + }; + int file_fd, ruleset_fd; + + /* Enables Landlock. */ + ruleset_fd = create_ruleset(_metadata, variant->handled, rules); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + file_fd = open("/dev/zero", variant->open_mode); + ASSERT_LE(0, file_fd) + { + TH_LOG("Failed to open /dev/zero: %s", strerror(errno)); + } + + /* Checks that IOCTL commands return the expected errors. */ + EXPECT_EQ(variant->expected_fionread_result, + test_fionread_ioctl(file_fd)); + + /* Checks that unrestrictable commands are unrestricted. */ + EXPECT_EQ(0, ioctl(file_fd, FIOCLEX)); + EXPECT_EQ(0, ioctl(file_fd, FIONCLEX)); + EXPECT_EQ(0, ioctl(file_fd, FIONBIO, &flag)); + EXPECT_EQ(0, ioctl(file_fd, FIOASYNC, &flag)); + EXPECT_EQ(0, ioctl(file_fd, FIGETBSZ, &flag)); + + ASSERT_EQ(0, close(file_fd)); } /* clang-format off */ |