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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /security/landlock/id.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'security/landlock/id.c')
-rw-r--r--security/landlock/id.c295
1 files changed, 295 insertions, 0 deletions
diff --git a/security/landlock/id.c b/security/landlock/id.c
new file mode 100644
index 000000000..6c8769777
--- /dev/null
+++ b/security/landlock/id.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock - Unique identification number generator
+ *
+ * Copyright © 2024-2025 Microsoft Corporation
+ */
+
+#include <kunit/test.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/random.h>
+#include <linux/spinlock.h>
+
+#include "common.h"
+#include "id.h"
+
+#define COUNTER_PRE_INIT 0
+
+static atomic64_t next_id = ATOMIC64_INIT(COUNTER_PRE_INIT);
+
+static void __init init_id(atomic64_t *const counter, const u32 random_32bits)
+{
+ u64 init;
+
+ /*
+ * Ensures sure 64-bit values are always used by user space (or may
+ * fail with -EOVERFLOW), and makes this testable.
+ */
+ init = BIT_ULL(32);
+
+ /*
+ * Makes a large (2^32) boot-time value to limit ID collision in logs
+ * from different boots, and to limit info leak about the number of
+ * initially (relative to the reader) created elements (e.g. domains).
+ */
+ init += random_32bits;
+
+ /* Sets first or ignores. This will be the first ID. */
+ atomic64_cmpxchg(counter, COUNTER_PRE_INIT, init);
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static void __init test_init_min(struct kunit *const test)
+{
+ atomic64_t counter = ATOMIC64_INIT(COUNTER_PRE_INIT);
+
+ init_id(&counter, 0);
+ KUNIT_EXPECT_EQ(test, atomic64_read(&counter), 1ULL + U32_MAX);
+}
+
+static void __init test_init_max(struct kunit *const test)
+{
+ atomic64_t counter = ATOMIC64_INIT(COUNTER_PRE_INIT);
+
+ init_id(&counter, ~0);
+ KUNIT_EXPECT_EQ(test, atomic64_read(&counter), 1 + (2ULL * U32_MAX));
+}
+
+static void __init test_init_once(struct kunit *const test)
+{
+ const u64 first_init = 1ULL + U32_MAX;
+ atomic64_t counter = ATOMIC64_INIT(COUNTER_PRE_INIT);
+
+ init_id(&counter, 0);
+ KUNIT_EXPECT_EQ(test, atomic64_read(&counter), first_init);
+
+ init_id(&counter, ~0);
+ KUNIT_EXPECT_EQ_MSG(
+ test, atomic64_read(&counter), first_init,
+ "Should still have the same value after the subsequent init_id()");
+}
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
+
+void __init landlock_init_id(void)
+{
+ return init_id(&next_id, get_random_u32());
+}
+
+/*
+ * It's not worth it to try to hide the monotonic counter because it can still
+ * be inferred (with N counter ranges), and if we are allowed to read the inode
+ * number we should also be allowed to read the time creation anyway, and it
+ * can be handy to store and sort domain IDs for user space.
+ *
+ * Returns the value of next_id and increment it to let some space for the next
+ * one.
+ */
+static u64 get_id_range(size_t number_of_ids, atomic64_t *const counter,
+ u8 random_4bits)
+{
+ u64 id, step;
+
+ /*
+ * We should return at least 1 ID, and we may need a set of consecutive
+ * ones (e.g. to generate a set of inodes).
+ */
+ if (WARN_ON_ONCE(number_of_ids <= 0))
+ number_of_ids = 1;
+
+ /*
+ * Blurs the next ID guess with 1/16 ratio. We get 2^(64 - 4) -
+ * (2 * 2^32), so a bit less than 2^60 available IDs, which should be
+ * much more than enough considering the number of CPU cycles required
+ * 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 &= 0b1111;
+ step = number_of_ids + random_4bits;
+
+ /* It is safe to cast a signed atomic to an unsigned value. */
+ id = atomic64_fetch_add(step, counter);
+
+ /* Warns if landlock_init_id() was not called. */
+ WARN_ON_ONCE(id == COUNTER_PRE_INIT);
+ return id;
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static u8 get_random_u8_positive(void)
+{
+ /* max() evaluates its arguments once. */
+ return max(1, get_random_u8());
+}
+
+static void test_range1_rand0(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, 0), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ init + 1);
+}
+
+static void test_range1_rand1(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, 1), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ 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_positive(), &counter,
+ get_random_u8()),
+ init + 16);
+}
+
+static void test_range1_rand16(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, 16), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ init + 1);
+}
+
+static void test_range2_rand0(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, 0), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ init + 2);
+}
+
+static void test_range2_rand1(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, 1), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ init + 3);
+}
+
+static void test_range2_rand2(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, 2), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ 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_positive(), &counter,
+ get_random_u8()),
+ init + 17);
+}
+
+static void test_range2_rand16(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, 16), init);
+ KUNIT_EXPECT_EQ(test,
+ get_id_range(get_random_u8_positive(), &counter,
+ get_random_u8()),
+ init + 2);
+}
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
+
+/**
+ * landlock_get_id_range - Get a range of unique IDs
+ *
+ * @number_of_ids: Number of IDs to hold. Must be greater than one.
+ *
+ * Return: The first ID in the range.
+ */
+u64 landlock_get_id_range(size_t number_of_ids)
+{
+ return get_id_range(number_of_ids, &next_id, get_random_u8());
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static struct kunit_case __refdata test_cases[] = {
+ /* clang-format off */
+ KUNIT_CASE(test_init_min),
+ KUNIT_CASE(test_init_max),
+ 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 */
+};
+
+static struct kunit_suite test_suite = {
+ .name = "landlock_id",
+ .test_cases = test_cases,
+};
+
+kunit_test_init_section_suite(test_suite);
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */