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authorMarco Elver <elver@google.com>2022-01-29 13:41:11 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-01-30 09:56:58 +0200
commit09c6304e38e440b93a9ebf3f3cf75cd6cb529f91 (patch)
treee98589d999dc837233e764118d1e7d5d5f76a91e
parent0226bd64da52aa23120d1450c37a424387827a21 (diff)
kasan: test: fix compatibility with FORTIFY_SOURCE
With CONFIG_FORTIFY_SOURCE enabled, string functions will also perform dynamic checks using __builtin_object_size(ptr), which when failed will panic the kernel. Because the KASAN test deliberately performs out-of-bounds operations, the kernel panics with FORTIFY_SOURCE, for example: | kernel BUG at lib/string_helpers.c:910! | invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI | CPU: 1 PID: 137 Comm: kunit_try_catch Tainted: G B 5.16.0-rc3+ #3 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 | RIP: 0010:fortify_panic+0x19/0x1b | ... | Call Trace: | kmalloc_oob_in_memset.cold+0x16/0x16 | ... Fix it by also hiding `ptr` from the optimizer, which will ensure that __builtin_object_size() does not return a valid size, preventing fortified string functions from panicking. Link: https://lkml.kernel.org/r/20220124160744.1244685-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Reported-by: Nico Pache <npache@redhat.com> Reviewed-by: Nico Pache <npache@redhat.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--lib/test_kasan.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 847cdbefab46..26a5c9007653 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -492,6 +492,7 @@ static void kmalloc_oob_in_memset(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
memset(ptr, 0, size + KASAN_GRANULE_SIZE));
@@ -515,6 +516,7 @@ static void kmalloc_memmove_negative_size(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(invalid_size);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
@@ -531,6 +533,7 @@ static void kmalloc_memmove_invalid_size(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
kfree(ptr);
@@ -893,6 +896,7 @@ static void kasan_memchr(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_ptr_result = memchr(ptr, '1', size + 1));
@@ -919,6 +923,7 @@ static void kasan_memcmp(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset(arr, 0, sizeof(arr));
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_int_result = memcmp(ptr, arr, size+1));