# \[PATCH\] selftests/landlock: fix the regex\_escape() error check - From: Sasha Levin \ - Date: 2026-11-03 16:39:19 - List: linux-security-module - Page: https://ratatoskr.run/linux-security-module/2026/11/17854648 - Thread: https://ratatoskr.run/linux-security-module/2026/11/17854648/t.md ```text regex_escape() returns (char *)-ENOMEM when the buffer is too small, but matches_log_fs_extra() checks the returned pointer with "< 0", which is never true, and goes on with a bogus cursor. On 32-bit architectures gcc also warns about the cast of the pointer in the error return: fs_test.c:7474:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] Compare against (char *)-ENOMEM instead. The size left after the escaped path also subtracts the prefix a second time, which can make a long path fail with -E2BIG. Compute it from the cursor instead. Fixes: 316d06b01130 ("selftests/landlock: Add audit tests for filesystem") Signed-off-by: Sasha Levin --- Found with 32-bit builds of the selftests (gcc 16 and clang 21 with -m32, with and without -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64); KernelCI's 32-bit arm builds show the same warnings. The changed files build without them now, and the x86_64 builds don't change. tools/testing/selftests/landlock/fs_test.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index f725882fa4a78..27a78434d1c21 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -7470,10 +7470,10 @@ static int matches_log_fs_extra(struct __test_metadata *const _metadata, log_match_cursor = regex_escape(absolute_path, log_match_cursor, log_match_remaining); free(absolute_path); - if (log_match_cursor < 0) - return (long long)log_match_cursor; + if (log_match_cursor == (char *)-ENOMEM) + return -ENOMEM; - log_match_remaining -= log_match_cursor - log_match; + log_match_remaining = sizeof(log_match) - (log_match_cursor - log_match); chunk_len = snprintf(log_match_cursor, log_match_remaining, "\" dev=\"[^\"]\\+\" ino=[0-9]\\+%s$", extra ?: ""); -- 2.53.0 ```