The patch titled
Subject: kasan: add match-all tag tests
has been added to the -mm tree. Its filename is
kasan-add-match-all-tag-tests.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-add-match-all-tag-tests.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-add-match-all-tag-tests.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: add match-all tag tests
Add 3 new tests for tag-based KASAN modes:
1. Check that match-all pointer tag is not assigned randomly.
2. Check that 0xff works as a match-all pointer tag.
3. Check that there are no match-all memory tags.
Note, that test #3 causes a significant number (255) of KASAN reports
to be printed during execution for the SW_TAGS mode.
Link: https://lkml.kernel.org/r/0f20f867d747b678604a68173a5f20fb8df9b756.1609871239.git.andreyknvl@xxxxxxxxxx
Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8eSigned-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_kasan.c | 93 +++++++++++++++++++++++++++++++++++++++++++++
mm/kasan/kasan.h | 6 ++
2 files changed, 99 insertions(+)
--- a/lib/test_kasan.c~kasan-add-match-all-tag-tests
+++ a/lib/test_kasan.c
@@ -13,6 +13,7 @@
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/printk.h>
+#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
@@ -790,6 +791,95 @@ static void vmalloc_oob(struct kunit *te
vfree(area);
}
+/*
+ * Check that match-all pointer tag is not assigned randomly for
+ * tag-based modes.
+ */
+static void match_all_not_assigned(struct kunit *test)
+{
+ char *ptr;
+ struct page *pages;
+ int i, size, order;
+
+ for (i = 0; i < 256; i++) {
+ size = get_random_int() % KMALLOC_MAX_SIZE;
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+ kfree(ptr);
+ }
+
+ for (i = 0; i < 256; i++) {
+ order = get_random_int() % 4;
+ pages = alloc_pages(GFP_KERNEL, order);
+ ptr = page_address(pages);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+ free_pages((unsigned long)ptr, order);
+ }
+}
+
+/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
+static void match_all_ptr_tag(struct kunit *test)
+{
+ char *ptr;
+ u8 tag;
+
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+ kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
+ return;
+ }
+
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+ /* Backup the assigned tag. */
+ tag = get_tag(ptr);
+ KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
+
+ /* Reset the tag to 0xff.*/
+ ptr = set_tag(ptr, KASAN_TAG_KERNEL);
+
+ /* This access shouldn't trigger a KASAN report. */
+ *ptr = 0;
+
+ /* Recover the pointer tag and free. */
+ ptr = set_tag(ptr, tag);
+ kfree(ptr);
+}
+
+/* Check that there are no match-all memory tags for tag-based modes. */
+static void match_all_mem_tag(struct kunit *test)
+{
+ char *ptr;
+ int tag;
+
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+ kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required");
+ return;
+ }
+
+ ptr = kmalloc(128, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+
+ /* For each possible tag value not matching the pointer tag. */
+ for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
+ if (tag == get_tag(ptr))
+ continue;
+
+ /* Mark the first memory granule with the chosen memory tag. */
+ kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
+
+ /* This access must cause a KASAN report. */
+ KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
+ }
+
+ /* Recover the memory tag and free. */
+ kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
+ kfree(ptr);
+}
+
static struct kunit_case kasan_kunit_test_cases[] = {
KUNIT_CASE(kmalloc_oob_right),
KUNIT_CASE(kmalloc_oob_left),
@@ -829,6 +919,9 @@ static struct kunit_case kasan_kunit_tes
KUNIT_CASE(kasan_bitops_tags),
KUNIT_CASE(kmalloc_double_kzfree),
KUNIT_CASE(vmalloc_oob),
+ KUNIT_CASE(match_all_not_assigned),
+ KUNIT_CASE(match_all_ptr_tag),
+ KUNIT_CASE(match_all_mem_tag),
{}
};
--- a/mm/kasan/kasan.h~kasan-add-match-all-tag-tests
+++ a/mm/kasan/kasan.h
@@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_
#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
#define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
+#ifdef CONFIG_KASAN_HW_TAGS
+#define KASAN_TAG_MIN 0xF0 /* mimimum value for random tags */
+#else
+#define KASAN_TAG_MIN 0x00 /* mimimum value for random tags */
+#endif
+
#ifdef CONFIG_KASAN_GENERIC
#define KASAN_FREE_PAGE 0xFF /* page was freed */
#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-prefix-exported-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adopt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
