From: Günther Noack Date: Fri, 27 Mar 2026 16:48:33 +0000 (+0100) Subject: selftests/landlock: Test LANDLOCK_ACCESS_FS_RESOLVE_UNIX X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9da41c65c907329a1848418cdc11fb10cc341217;p=thirdparty%2Fkernel%2Flinux.git selftests/landlock: Test LANDLOCK_ACCESS_FS_RESOLVE_UNIX * Extract common helpers from an existing IOCTL test that also uses pathname unix(7) sockets. * These tests use the common scoped domains fixture which is also used in other Landlock scoping tests and which was used in Tingmao Wang's earlier patch set in [1]. These tests exercise the cross product of the following scenarios: * Stream connect(), Datagram connect(), Datagram sendmsg() and Seqpacket connect(). * Child-to-parent and parent-to-child communication * The Landlock policy configuration as listed in the scoped_domains fixture. * In the default variant, Landlock domains are only placed where prescribed in the fixture. * In the "ALL_DOMAINS" variant, Landlock domains are also placed in the places where the fixture says to omit them, but with a LANDLOCK_RULE_PATH_BENEATH that allows connection. Cc: Justin Suess Cc: Tingmao Wang Cc: Mickaël Salaün Link[1]: https://lore.kernel.org/all/53b9883648225d5a08e82d2636ab0b4fda003bc9.1767115163.git.m@maowtm.org/ Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20260327164838.38231-9-gnoack3000@gmail.com Signed-off-by: Mickaël Salaün --- diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 9fdd3b8f7b11c..f8cfd31335e14 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -4358,30 +4358,66 @@ TEST_F_FORK(layout1, named_pipe_ioctl) 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) +/* + * set_up_named_unix_server - Create a pathname unix socket + * + * If the socket type is not SOCK_DGRAM, also invoke listen(2). + * + * Return: The listening FD - it is the caller responsibility to close it. + */ +static int set_up_named_unix_server(struct __test_metadata *const _metadata, + int type, const char *const path) { - const char *const path = file1_s1d1; - int srv_fd, cli_fd, ruleset_fd; - struct sockaddr_un srv_un = { + int fd; + struct sockaddr_un addr = { .sun_family = AF_UNIX, }; - struct sockaddr_un cli_un = { + + fd = socket(AF_UNIX, type, 0); + ASSERT_LE(0, fd); + + ASSERT_LT(strlen(path), sizeof(addr.sun_path)); + strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1); + + ASSERT_EQ(0, bind(fd, (struct sockaddr *)&addr, sizeof(addr))); + + if (type != SOCK_DGRAM) + ASSERT_EQ(0, listen(fd, 10 /* qlen */)); + return fd; +} + +/* + * test_connect_named_unix - connect to the given named UNIX socket + * + * Return: The errno from connect(), or 0 + */ +static int test_connect_named_unix(struct __test_metadata *const _metadata, + int fd, const char *const path) +{ + struct sockaddr_un addr = { .sun_family = AF_UNIX, }; + + ASSERT_LT(strlen(path), sizeof(addr.sun_path)); + strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1); + + if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) + return errno; + return 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; const struct landlock_ruleset_attr attr = { .handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV, }; /* Sets up a server */ ASSERT_EQ(0, unlink(path)); - srv_fd = socket(AF_UNIX, SOCK_STREAM, 0); - ASSERT_LE(0, srv_fd); - - strncpy(srv_un.sun_path, path, sizeof(srv_un.sun_path)); - ASSERT_EQ(0, bind(srv_fd, (struct sockaddr *)&srv_un, sizeof(srv_un))); - - ASSERT_EQ(0, listen(srv_fd, 10 /* qlen */)); + srv_fd = set_up_named_unix_server(_metadata, SOCK_STREAM, path); /* Enables Landlock. */ ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0); @@ -4393,9 +4429,7 @@ TEST_F_FORK(layout1, named_unix_domain_socket_ioctl) cli_fd = socket(AF_UNIX, SOCK_STREAM, 0); ASSERT_LE(0, cli_fd); - strncpy(cli_un.sun_path, path, sizeof(cli_un.sun_path)); - ASSERT_EQ(0, - connect(cli_fd, (struct sockaddr *)&cli_un, sizeof(cli_un))); + ASSERT_EQ(0, test_connect_named_unix(_metadata, cli_fd, path)); /* FIONREAD and other IOCTLs should not be forbidden. */ EXPECT_EQ(0, test_fionread_ioctl(cli_fd)); @@ -4570,6 +4604,330 @@ TEST_F_FORK(ioctl, handle_file_access_file) ASSERT_EQ(0, close(file_fd)); } +/* + * test_sendto_named_unix - sendto to the given named UNIX socket + * + * sendto() is equivalent to sendmsg() in this respect. + * + * Return: The errno from sendto(), or 0 + */ +static int test_sendto_named_unix(struct __test_metadata *const _metadata, + int fd, const char *const path) +{ + static const char buf[] = "dummy"; + struct sockaddr_un addr = { + .sun_family = AF_UNIX, + }; + + ASSERT_LT(strlen(path), sizeof(addr.sun_path)); + strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1); + + if (sendto(fd, buf, sizeof(buf), 0, (struct sockaddr *)&addr, + sizeof(addr)) == -1) + return errno; + return 0; +} + +/* clang-format off */ +FIXTURE(scoped_domains) {}; +/* clang-format on */ + +#include "scoped_base_variants.h" + +FIXTURE_SETUP(scoped_domains) +{ + drop_caps(_metadata); +}; + +FIXTURE_TEARDOWN(scoped_domains) +{ +} + +static void enforce_fs_resolve_unix(struct __test_metadata *const _metadata, + const struct rule rules[]) +{ + if (rules) { + int fd = create_ruleset(_metadata, + LANDLOCK_ACCESS_FS_RESOLVE_UNIX, rules); + enforce_ruleset(_metadata, fd); + EXPECT_EQ(0, close(fd)); + } else { + struct landlock_ruleset_attr attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_RESOLVE_UNIX, + }; + drop_access_rights(_metadata, &attr); + } +} + +/* + * Flags for test_connect_to_parent and test_connect_to_child: + * + * USE_SENDTO: Use sendto() instead of connect() (for SOCK_DGRAM only) + * ENFORCE_ALL: Enforce a Landlock domain even when the variant says + * we shouldn't. We enforce a domain where the path is allow-listed, + * and expect the behavior to be the same as if none was used. + */ +#define USE_SENDTO (1 << 0) +#define ENFORCE_ALL (1 << 1) + +static void test_connect_to_parent(struct __test_metadata *const _metadata, + const FIXTURE_VARIANT(scoped_domains) * + variant, + int sock_type, int flags) +{ + const char *const path = "sock"; + const struct rule rules[] = { + { + .path = ".", + .access = LANDLOCK_ACCESS_FS_RESOLVE_UNIX, + }, + {}, + }; + int cli_fd, srv_fd, res, status; + pid_t child_pid; + int readiness_pipe[2]; + char buf[1]; + + if (variant->domain_both) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + unlink(path); + ASSERT_EQ(0, pipe2(readiness_pipe, O_CLOEXEC)); + + child_pid = fork(); + ASSERT_LE(0, child_pid); + + if (child_pid == 0) { + if (variant->domain_child) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + /* Wait for server to be available. */ + EXPECT_EQ(0, close(readiness_pipe[1])); + EXPECT_EQ(1, read(readiness_pipe[0], &buf, 1)); + EXPECT_EQ(0, close(readiness_pipe[0])); + + /* Talk to server. */ + cli_fd = socket(AF_UNIX, sock_type, 0); + ASSERT_LE(0, cli_fd); + + if (flags & USE_SENDTO) + res = test_sendto_named_unix(_metadata, cli_fd, path); + else + res = test_connect_named_unix(_metadata, cli_fd, path); + + EXPECT_EQ(variant->domain_child ? EACCES : 0, res); + + /* Clean up. */ + EXPECT_EQ(0, close(cli_fd)); + + _exit(_metadata->exit_code); + return; + } + + if (variant->domain_parent) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + srv_fd = set_up_named_unix_server(_metadata, sock_type, path); + + /* Tell the child that it can connect. */ + EXPECT_EQ(0, close(readiness_pipe[0])); + EXPECT_EQ(sizeof(buf), write(readiness_pipe[1], buf, sizeof(buf))); + EXPECT_EQ(0, close(readiness_pipe[1])); + + /* Wait for child. */ + ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); + EXPECT_EQ(1, WIFEXITED(status)); + EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); + + /* Clean up. */ + EXPECT_EQ(0, close(srv_fd)); + EXPECT_EQ(0, unlink(path)); +} + +static void test_connect_to_child(struct __test_metadata *const _metadata, + const FIXTURE_VARIANT(scoped_domains) * + variant, + int sock_type, int flags) +{ + const char *const path = "sock"; + const struct rule rules[] = { + { + .path = ".", + .access = LANDLOCK_ACCESS_FS_RESOLVE_UNIX, + }, + {}, + }; + int readiness_pipe[2]; + int shutdown_pipe[2]; + int cli_fd, srv_fd, res, status; + pid_t child_pid; + char buf[1]; + + if (variant->domain_both) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + unlink(path); + ASSERT_EQ(0, pipe2(readiness_pipe, O_CLOEXEC)); + ASSERT_EQ(0, pipe2(shutdown_pipe, O_CLOEXEC)); + + child_pid = fork(); + ASSERT_LE(0, child_pid); + + if (child_pid == 0) { + if (variant->domain_child) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + srv_fd = set_up_named_unix_server(_metadata, sock_type, path); + + /* Tell the parent that it can connect. */ + EXPECT_EQ(0, close(readiness_pipe[0])); + EXPECT_EQ(sizeof(buf), + write(readiness_pipe[1], buf, sizeof(buf))); + EXPECT_EQ(0, close(readiness_pipe[1])); + + /* Wait until it is time to shut down. */ + EXPECT_EQ(0, close(shutdown_pipe[1])); + EXPECT_EQ(1, read(shutdown_pipe[0], &buf, 1)); + EXPECT_EQ(0, close(shutdown_pipe[0])); + + /* Cleanup */ + EXPECT_EQ(0, close(srv_fd)); + EXPECT_EQ(0, unlink(path)); + + _exit(_metadata->exit_code); + return; + } + + if (variant->domain_parent) + enforce_fs_resolve_unix(_metadata, NULL); + else if (flags & ENFORCE_ALL) + enforce_fs_resolve_unix(_metadata, rules); + + /* Wait for server to be available. */ + EXPECT_EQ(0, close(readiness_pipe[1])); + EXPECT_EQ(1, read(readiness_pipe[0], &buf, 1)); + EXPECT_EQ(0, close(readiness_pipe[0])); + + /* Talk to server. */ + cli_fd = socket(AF_UNIX, sock_type, 0); + ASSERT_LE(0, cli_fd); + + if (flags & USE_SENDTO) + res = test_sendto_named_unix(_metadata, cli_fd, path); + else + res = test_connect_named_unix(_metadata, cli_fd, path); + + EXPECT_EQ(variant->domain_parent ? EACCES : 0, res); + + /* Clean up. */ + EXPECT_EQ(0, close(cli_fd)); + + /* Tell the server to shut down. */ + EXPECT_EQ(0, close(shutdown_pipe[0])); + EXPECT_EQ(sizeof(buf), write(shutdown_pipe[1], buf, sizeof(buf))); + EXPECT_EQ(0, close(shutdown_pipe[1])); + + /* Wait for child. */ + ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); + EXPECT_EQ(1, WIFEXITED(status)); + EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); +} + +TEST_F(scoped_domains, unix_stream_connect_to_parent) +{ + test_connect_to_parent(_metadata, variant, SOCK_STREAM, 0); +} + +TEST_F(scoped_domains, unix_dgram_connect_to_parent) +{ + test_connect_to_parent(_metadata, variant, SOCK_DGRAM, 0); +} + +TEST_F(scoped_domains, unix_dgram_sendmsg_to_parent) +{ + test_connect_to_parent(_metadata, variant, SOCK_DGRAM, USE_SENDTO); +} + +TEST_F(scoped_domains, unix_seqpacket_connect_to_parent) +{ + test_connect_to_parent(_metadata, variant, SOCK_SEQPACKET, 0); +} + +TEST_F(scoped_domains, unix_stream_connect_to_parent_full) +{ + test_connect_to_parent(_metadata, variant, SOCK_STREAM, ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_dgram_connect_to_parent_full) +{ + test_connect_to_parent(_metadata, variant, SOCK_DGRAM, ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_dgram_sendmsg_to_parent_full) +{ + test_connect_to_parent(_metadata, variant, SOCK_DGRAM, + USE_SENDTO | ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_seqpacket_connect_to_parent_full) +{ + test_connect_to_parent(_metadata, variant, SOCK_SEQPACKET, ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_stream_connect_to_child) +{ + test_connect_to_child(_metadata, variant, SOCK_STREAM, 0); +} + +TEST_F(scoped_domains, unix_dgram_connect_to_child) +{ + test_connect_to_child(_metadata, variant, SOCK_DGRAM, 0); +} + +TEST_F(scoped_domains, unix_dgram_sendmsg_to_child) +{ + test_connect_to_child(_metadata, variant, SOCK_DGRAM, USE_SENDTO); +} + +TEST_F(scoped_domains, unix_seqpacket_connect_to_child) +{ + test_connect_to_child(_metadata, variant, SOCK_SEQPACKET, 0); +} + +TEST_F(scoped_domains, unix_stream_connect_to_child_full) +{ + test_connect_to_child(_metadata, variant, SOCK_STREAM, ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_dgram_connect_to_child_full) +{ + test_connect_to_child(_metadata, variant, SOCK_DGRAM, ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_dgram_sendmsg_to_child_full) +{ + test_connect_to_child(_metadata, variant, SOCK_DGRAM, + USE_SENDTO | ENFORCE_ALL); +} + +TEST_F(scoped_domains, unix_seqpacket_connect_to_child_full) +{ + test_connect_to_child(_metadata, variant, SOCK_SEQPACKET, ENFORCE_ALL); +} + +#undef USE_SENDTO +#undef ENFORCE_ALL + /* clang-format off */ FIXTURE(layout1_bind) {}; /* clang-format on */