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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /security/landlock/id.c
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linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
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 */