From 3039ed432745f8fdf5cbb43fdc60b2e1aad624c1 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Mon, 12 May 2025 11:37:30 +0200 Subject: [PATCH] landlock: Improve bit operations in audit code MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Use the BIT() and BIT_ULL() macros in the new audit code instead of explicit shifts to improve readability. Use bitmask instead of modulo operation to simplify code. Add test_range1_rand15() and test_range2_rand15() KUnit tests to improve get_id_range() coverage. Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20250512093732.1408485-1-mic@digikod.net Signed-off-by: Mickaël Salaün --- security/landlock/audit.c | 2 +- security/landlock/id.c | 33 +++++++++++++++++++++++++++++++-- security/landlock/syscalls.c | 3 ++- 3 files changed, 34 insertions(+), 4 deletions(-) diff --git a/security/landlock/audit.c b/security/landlock/audit.c index 58d5c40d4d0e..c52d079cdb77 100644 --- a/security/landlock/audit.c +++ b/security/landlock/audit.c @@ -437,7 +437,7 @@ void landlock_log_denial(const struct landlock_cred_security *const subject, return; /* Checks if the current exec was restricting itself. */ - if (subject->domain_exec & (1 << youngest_layer)) { + if (subject->domain_exec & BIT(youngest_layer)) { /* Ignores denials for the same execution. */ if (!youngest_denied->log_same_exec) return; diff --git a/security/landlock/id.c b/security/landlock/id.c index 11fab9259c15..56f7cc0fc744 100644 --- a/security/landlock/id.c +++ b/security/landlock/id.c @@ -7,6 +7,7 @@ #include #include +#include #include #include @@ -25,7 +26,7 @@ static void __init init_id(atomic64_t *const counter, const u32 random_32bits) * Ensures sure 64-bit values are always used by user space (or may * fail with -EOVERFLOW), and makes this testable. */ - init = 1ULL << 32; + init = BIT_ULL(32); /* * Makes a large (2^32) boot-time value to limit ID collision in logs @@ -105,7 +106,7 @@ static u64 get_id_range(size_t number_of_ids, atomic64_t *const counter, * to get a new ID (e.g. a full landlock_restrict_self() call), and the * cost of draining all available IDs during the system's uptime. */ - random_4bits = random_4bits % (1 << 4); + random_4bits &= 0b1111; step = number_of_ids + random_4bits; /* It is safe to cast a signed atomic to an unsigned value. */ @@ -144,6 +145,19 @@ static void test_range1_rand1(struct kunit *const test) init + 2); } +static void test_range1_rand15(struct kunit *const test) +{ + atomic64_t counter; + u64 init; + + init = get_random_u32(); + atomic64_set(&counter, init); + KUNIT_EXPECT_EQ(test, get_id_range(1, &counter, 15), init); + KUNIT_EXPECT_EQ( + test, get_id_range(get_random_u8(), &counter, get_random_u8()), + init + 16); +} + static void test_range1_rand16(struct kunit *const test) { atomic64_t counter; @@ -196,6 +210,19 @@ static void test_range2_rand2(struct kunit *const test) init + 4); } +static void test_range2_rand15(struct kunit *const test) +{ + atomic64_t counter; + u64 init; + + init = get_random_u32(); + atomic64_set(&counter, init); + KUNIT_EXPECT_EQ(test, get_id_range(2, &counter, 15), init); + KUNIT_EXPECT_EQ( + test, get_id_range(get_random_u8(), &counter, get_random_u8()), + init + 17); +} + static void test_range2_rand16(struct kunit *const test) { atomic64_t counter; @@ -232,10 +259,12 @@ static struct kunit_case __refdata test_cases[] = { KUNIT_CASE(test_init_once), KUNIT_CASE(test_range1_rand0), KUNIT_CASE(test_range1_rand1), + KUNIT_CASE(test_range1_rand15), KUNIT_CASE(test_range1_rand16), KUNIT_CASE(test_range2_rand0), KUNIT_CASE(test_range2_rand1), KUNIT_CASE(test_range2_rand2), + KUNIT_CASE(test_range2_rand15), KUNIT_CASE(test_range2_rand16), {} /* clang-format on */ diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index b9561e3417ae..33eafb71e4f3 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -9,6 +9,7 @@ #include #include +#include #include #include #include @@ -563,7 +564,7 @@ SYSCALL_DEFINE2(landlock_restrict_self, const int, ruleset_fd, const __u32, new_llcred->domain = new_dom; #ifdef CONFIG_AUDIT - new_llcred->domain_exec |= 1 << (new_dom->num_layers - 1); + new_llcred->domain_exec |= BIT(new_dom->num_layers - 1); #endif /* CONFIG_AUDIT */ return commit_creds(new_cred); -- 2.25.1