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authorAndrey Konovalov <andreyknvl@google.com>2021-02-24 12:05:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:31 -0800
commitf05842cfb9ae25b5e78c618429c4716d9e4d5fc8 (patch)
tree903a626a0cf734d328721455ef8e8b49b9ceb47e
parent573a48092313dec7b254d9dbcc2db62167f00456 (diff)
kasan, arm64: allow using KUnit tests with HW_TAGS mode
On a high level, this patch allows running KUnit KASAN tests with the hardware tag-based KASAN mode. Internally, this change reenables tag checking at the end of each KASAN test that triggers a tag fault and leads to tag checking being disabled. Also simplify is_write calculation in report_tag_fault. With this patch KASAN tests are still failing for the hardware tag-based mode; fixes come in the next few patches. [andreyknvl@google.com: export HW_TAGS symbols for KUnit tests] Link: https://lkml.kernel.org/r/e7eeb252da408b08f0c81b950a55fb852f92000b.1613155970.git.andreyknvl@google.com Link: https://linux-review.googlesource.com/id/Id94dc9eccd33b23cda4950be408c27f879e474c8 Link: https://lkml.kernel.org/r/51b23112cf3fd62b8f8e9df81026fa2b15870501.1610733117.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Marco Elver <elver@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/arm64/include/asm/memory.h1
-rw-r--r--arch/arm64/include/asm/mte-kasan.h12
-rw-r--r--arch/arm64/kernel/mte.c12
-rw-r--r--arch/arm64/mm/fault.c20
-rw-r--r--lib/Kconfig.kasan4
-rw-r--r--lib/test_kasan.c42
-rw-r--r--mm/kasan/hw_tags.c16
-rw-r--r--mm/kasan/kasan.h21
8 files changed, 107 insertions, 21 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index bc09af26c1b8..c759faf7a1ff 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -244,6 +244,7 @@ static inline const void *__tag_set(const void *addr, u8 tag)
#ifdef CONFIG_KASAN_HW_TAGS
#define arch_enable_tagging() mte_enable_kernel()
+#define arch_set_tagging_report_once(state) mte_set_report_once(state)
#define arch_init_tags(max_tag) mte_init_tags(max_tag)
#define arch_get_random_tag() mte_get_random_tag()
#define arch_get_mem_tag(addr) mte_get_mem_tag(addr)
diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 26349a4b5e2e..3748d5bb88c0 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -32,6 +32,9 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag);
void mte_enable_kernel(void);
void mte_init_tags(u64 max_tag);
+void mte_set_report_once(bool state);
+bool mte_report_once(void);
+
#else /* CONFIG_ARM64_MTE */
static inline u8 mte_get_ptr_tag(void *ptr)
@@ -60,6 +63,15 @@ static inline void mte_init_tags(u64 max_tag)
{
}
+static inline void mte_set_report_once(bool state)
+{
+}
+
+static inline bool mte_report_once(void)
+{
+ return false;
+}
+
#endif /* CONFIG_ARM64_MTE */
#endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 80b62fe49dcf..2cfc850809ce 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -25,6 +25,8 @@
u64 gcr_kernel_excl __ro_after_init;
+static bool report_fault_once = true;
+
static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
{
pte_t old_pte = READ_ONCE(*ptep);
@@ -158,6 +160,16 @@ void mte_enable_kernel(void)
isb();
}
+void mte_set_report_once(bool state)
+{
+ WRITE_ONCE(report_fault_once, state);
+}
+
+bool mte_report_once(void)
+{
+ return READ_ONCE(report_fault_once);
+}
+
static void update_sctlr_el1_tcf0(u64 tcf0)
{
/* ISB required for the kernel uaccess routines */
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 2e339f0bd958..dc9f96442edc 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -302,12 +302,24 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
static void report_tag_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+ static bool reported;
+ bool is_write;
+
+ if (READ_ONCE(reported))
+ return;
+
+ /*
+ * This is used for KASAN tests and assumes that no MTE faults
+ * happened before running the tests.
+ */
+ if (mte_report_once())
+ WRITE_ONCE(reported, true);
/*
* SAS bits aren't set for all faults reported in EL1, so we can't
* find out access size.
*/
+ is_write = !!(esr & ESR_ELx_WNR);
kasan_report(addr, 0, is_write, regs->pc);
}
#else
@@ -319,12 +331,8 @@ static inline void report_tag_fault(unsigned long addr, unsigned int esr,
static void do_tag_recovery(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- static bool reported;
- if (!READ_ONCE(reported)) {
- report_tag_fault(addr, esr, regs);
- WRITE_ONCE(reported, true);
- }
+ report_tag_fault(addr, esr, regs);
/*
* Disable MTE Tag Checking on the local CPU for the current EL.
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index f5fa4ba126bf..3091432acb0a 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -190,11 +190,11 @@ config KASAN_KUNIT_TEST
kernel debugging features like KASAN.
For more information on KUnit and unit tests in general, please refer
- to the KUnit documentation in Documentation/dev-tools/kunit
+ to the KUnit documentation in Documentation/dev-tools/kunit.
config TEST_KASAN_MODULE
tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
- depends on m && KASAN
+ depends on m && KASAN && !KASAN_HW_TAGS
help
This is a part of the KASAN test suite that is incompatible with
KUnit. Currently includes tests that do bad copy_from/to_user
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c344fe506ffc..502709db41c0 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -41,16 +41,20 @@ static bool multishot;
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
- * first detected bug and panic the kernel if panic_on_warn is enabled.
+ * first detected bug and panic the kernel if panic_on_warn is enabled. For
+ * hardware tag-based KASAN also allow tag checking to be reenabled for each
+ * test, see the comment for KUNIT_EXPECT_KASAN_FAIL().
*/
static int kasan_test_init(struct kunit *test)
{
multishot = kasan_save_enable_multi_shot();
+ kasan_set_tagging_report_once(false);
return 0;
}
static void kasan_test_exit(struct kunit *test)
{
+ kasan_set_tagging_report_once(true);
kasan_restore_multi_shot(multishot);
}
@@ -59,19 +63,31 @@ static void kasan_test_exit(struct kunit *test)
* KASAN report; causes a test failure otherwise. This relies on a KUnit
* resource named "kasan_data". Do not use this name for KUnit resources
* outside of KASAN tests.
+ *
+ * For hardware tag-based KASAN, when a tag fault happens, tag checking is
+ * normally auto-disabled. When this happens, this test handler reenables
+ * tag checking. As tag checking can be only disabled or enabled per CPU, this
+ * handler disables migration (preemption).
*/
-#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
- fail_data.report_expected = true; \
- fail_data.report_found = false; \
- kunit_add_named_resource(test, \
- NULL, \
- NULL, \
- &resource, \
- "kasan_data", &fail_data); \
- expression; \
- KUNIT_EXPECT_EQ(test, \
- fail_data.report_expected, \
- fail_data.report_found); \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
+ migrate_disable(); \
+ fail_data.report_expected = true; \
+ fail_data.report_found = false; \
+ kunit_add_named_resource(test, \
+ NULL, \
+ NULL, \
+ &resource, \
+ "kasan_data", &fail_data); \
+ expression; \
+ KUNIT_EXPECT_EQ(test, \
+ fail_data.report_expected, \
+ fail_data.report_found); \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
+ if (fail_data.report_found) \
+ kasan_enable_tagging(); \
+ migrate_enable(); \
+ } \
} while (0)
#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index d558799b25b3..b31aeef505dd 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -185,3 +185,19 @@ struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
return &alloc_meta->free_track[0];
}
+
+#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
+
+void kasan_set_tagging_report_once(bool state)
+{
+ hw_set_tagging_report_once(state);
+}
+EXPORT_SYMBOL_GPL(kasan_set_tagging_report_once);
+
+void kasan_enable_tagging(void)
+{
+ hw_enable_tagging();
+}
+EXPORT_SYMBOL_GPL(kasan_enable_tagging);
+
+#endif
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 12932186a7f9..1298b79f9518 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -280,6 +280,9 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
#ifndef arch_init_tags
#define arch_init_tags(max_tag)
#endif
+#ifndef arch_set_tagging_report_once
+#define arch_set_tagging_report_once(state)
+#endif
#ifndef arch_get_random_tag
#define arch_get_random_tag() (0xFF)
#endif
@@ -292,12 +295,30 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
#define hw_enable_tagging() arch_enable_tagging()
#define hw_init_tags(max_tag) arch_init_tags(max_tag)
+#define hw_set_tagging_report_once(state) arch_set_tagging_report_once(state)
#define hw_get_random_tag() arch_get_random_tag()
#define hw_get_mem_tag(addr) arch_get_mem_tag(addr)
#define hw_set_mem_tag_range(addr, size, tag) arch_set_mem_tag_range((addr), (size), (tag))
+#else /* CONFIG_KASAN_HW_TAGS */
+
+#define hw_enable_tagging()
+#define hw_set_tagging_report_once(state)
+
#endif /* CONFIG_KASAN_HW_TAGS */
+#if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
+
+void kasan_set_tagging_report_once(bool state);
+void kasan_enable_tagging(void);
+
+#else /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */
+
+static inline void kasan_set_tagging_report_once(bool state) { }
+static inline void kasan_enable_tagging(void) { }
+
+#endif /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */
+
#ifdef CONFIG_KASAN_SW_TAGS
u8 kasan_random_tag(void);
#elif defined(CONFIG_KASAN_HW_TAGS)