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| author | Nirjhar Roy <nirjhar@linux.ibm.com> | 2024-10-18 23:16:01 +0530 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-14 22:49:19 -0800 |
| commit | 811808d365398680b628d2b88aafeba77c88691a (patch) | |
| tree | 26026a66991f95ef51e606bc4ab09e02f5a19562 | |
| parent | f364cdeb38938f9d03061682b8ff3779dd1730e5 (diff) | |
| download | lwn-811808d365398680b628d2b88aafeba77c88691a.tar.gz lwn-811808d365398680b628d2b88aafeba77c88691a.zip | |
mm/kfence: add a new kunit test test_use_after_free_read_nofault()
Faults from copy_from_kernel_nofault() need to be handled by fixup table
and should not be handled by kfence. Otherwise while reading /proc/kcore
which uses copy_from_kernel_nofault(), kfence can generate false
negatives. This can happen when /proc/kcore ends up reading an unmapped
address from kfence pool.
Let's add a testcase to cover this case.
Link: https://lkml.kernel.org/r/210e561f7845697a32de44b643393890f180069f.1729272697.git.ritesh.list@gmail.com
Signed-off-by: Nirjhar Roy <nirjhar@linux.ibm.com>
Co-developed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/kfence/kfence_test.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index 00fd17285285..f65fb182466d 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -383,6 +383,22 @@ static void test_use_after_free_read(struct kunit *test) KUNIT_EXPECT_TRUE(test, report_matches(&expect)); } +static void test_use_after_free_read_nofault(struct kunit *test) +{ + const size_t size = 32; + char *addr; + char dst; + int ret; + + setup_test_cache(test, size, 0, NULL); + addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + test_free(addr); + /* Use after free with *_nofault() */ + ret = copy_from_kernel_nofault(&dst, addr, 1); + KUNIT_EXPECT_EQ(test, ret, -EFAULT); + KUNIT_EXPECT_FALSE(test, report_available()); +} + static void test_double_free(struct kunit *test) { const size_t size = 32; @@ -780,6 +796,7 @@ static struct kunit_case kfence_test_cases[] = { KFENCE_KUNIT_CASE(test_out_of_bounds_read), KFENCE_KUNIT_CASE(test_out_of_bounds_write), KFENCE_KUNIT_CASE(test_use_after_free_read), + KFENCE_KUNIT_CASE(test_use_after_free_read_nofault), KFENCE_KUNIT_CASE(test_double_free), KFENCE_KUNIT_CASE(test_invalid_addr_free), KFENCE_KUNIT_CASE(test_corruption), |