[PATCH v4] Add test for io_uring openat access control with Landlock rules
Dorine Tipo
dorine.a.tipo at gmail.com
Thu Apr 4 21:16:37 UTC 2024
This v4 patch expands Landlock test coverage to include io_uring
operations. It also introduces a test for IORING_OP_OPENAT with Landlock
rules, verifying allowed and restricted O_RDONLY access. This makes sure that
IORING_OP_OPENAT is well covered from security vulnerabilities by
ensuring Landlock controls access through io_uring.
It also updates Makefile to include -luring in the LDLIBS variable.
This ensures the test code has access to the necessary library for
io_uring operations.
The previous implementation of tests for the io_uring operation
IORING_OP_OPENAT in the Landlock fs_test suite was found to be incorrect
and ineffective.
This patch removes the previous implementation and introduces a new set
of tests that cover both allowed and denied access scenarios.
Signed-off-by: Dorine Tipo <dorine.a.tipo at gmail.com>
Changes since V1:
V2: - Consolidated two dependent patches in the V1 series into one patch
as suggested by Fabio.
- Updated The subject line to be more descriptive.
V3: - Added "selftests/landlock" subject prefix
- Revised wording in the commit message to accurately reflect the
test functionality as suggested by Mickaël.
- Updated the Fixture set_up and tear_down to create and remove the
necesssary files and folders for testing access.
- renamed allowed_ruleset_fd and disallowed_ruleset_fd to ruleset_fd
as suggest by Mickaël.
- Moved all variable declarations to the top of the function.
- Refactored the code to test only one allowed and one restricted
path instead of iterating through all the paths.
- Added comments to explain what is happening in different blocks
of code
- Removed the clang-format markers.
- Removed unused arguments in the function definition.
- Added a final rule struct with a null path to the allowed_rule
and disallowed_rule arrays as suggested by Fabio.
- CC'd the missing mailing lists as suggested by Shuah.
- All executables have been included in the .gitignore so no updates
are necessary.
V4: - Removed the previous implementation of the tests as they were not
correctly implemented.
---
tools/testing/selftests/landlock/Makefile | 4 +-
tools/testing/selftests/landlock/fs_test.c | 85 ++++++++++++++++++++++
2 files changed, 87 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile
index 348e2dbdb4e0..ab47d1dadb62 100644
--- a/tools/testing/selftests/landlock/Makefile
+++ b/tools/testing/selftests/landlock/Makefile
@@ -13,11 +13,11 @@ TEST_GEN_PROGS := $(src_test:.c=)
TEST_GEN_PROGS_EXTENDED := true
# Short targets:
-$(TEST_GEN_PROGS): LDLIBS += -lcap
+$(TEST_GEN_PROGS): LDLIBS += -lcap -luring
$(TEST_GEN_PROGS_EXTENDED): LDFLAGS += -static
include ../lib.mk
# Targets with $(OUTPUT)/ prefix:
-$(TEST_GEN_PROGS): LDLIBS += -lcap
+$(TEST_GEN_PROGS): LDLIBS += -lcap -luring
$(TEST_GEN_PROGS_EXTENDED): LDFLAGS += -static
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 9a6036fbf289..d1fae72e99be 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -21,7 +21,10 @@
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/vfs.h>
+#include <sys/types.h>
#include <unistd.h>
+#include <liburing.h>
+#include <linux/io_uring.h>
#include "common.h"
@@ -4874,4 +4877,86 @@ TEST_F_FORK(layout3_fs, release_inodes)
ASSERT_EQ(EACCES, test_open(TMP_DIR, O_RDONLY));
}
+/* test openat */
+static int test_openat(struct io_uring *ring, const char *path, int dfd)
+{
+ struct io_uring_cqe *cqe;
+ struct io_uring_sqe *sqe;
+ int ret;
+
+ sqe = io_uring_get_sqe(ring);
+ if (!sqe) {
+ fprintf(stderr, "get sqe failed\n");
+ goto err;
+ }
+ io_uring_prep_openat(sqe, dfd, path, O_RDONLY, 0);
+
+ ret = io_uring_submit(ring);
+ if (ret <= 0) {
+ fprintf(stderr, "sqe submit failed: %d\n", ret);
+ goto err;
+ }
+
+ ret = io_uring_wait_cqe(ring, &cqe);
+ if (ret < 0) {
+ fprintf(stderr, "wait completion %d\n", ret);
+ goto err;
+ }
+ ret = cqe->res;
+ io_uring_cqe_seen(ring, cqe);
+ return ret;
+err:
+ return -1;
+}
+
+TEST_F_FORK(layout1, openat_allowed)
+{
+ struct io_uring ring;
+ int ret;
+ const char *path = "file1_s1d3";
+ const struct rule rules[] = {
+ {
+ .path = path,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = NULL,
+ },
+ };
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, rules[0].access, rules);
+ ret = io_uring_queue_init(8, &ring, 0);
+
+ ASSERT_EQ(0, ret);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, test_openat(&ring, file1_s1d3, AT_FDCWD));
+}
+
+TEST_F_FORK(layout1, openat_denied)
+{
+ struct io_uring ring;
+ int ret;
+ const char *path = "file2_s1d3";
+ const struct rule rules[] = {
+ {
+ .path = path,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = NULL,
+ },
+ };
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, rules[0].access, rules);
+ ret = io_uring_queue_init(8, &ring, 0);
+
+ ASSERT_EQ(0, ret);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(EACCES, test_openat(&ring, file1_s1d3, AT_FDCWD));
+}
+
TEST_HARNESS_MAIN
--
2.25.1
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