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authorKees Cook <keescook@chromium.org>2021-11-05 13:36:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:33 -0700
commitd73dad4eb5ad8c31ac9cf358eb5a55825bafe706 (patch)
tree34585db952518be749bae401a60156977f93b540 /lib
parent8772716f96704c67b1e2a6ba175605b4fce2a252 (diff)
kasan: test: bypass __alloc_size checks
Intentional overflows, as performed by the KASAN tests, are detected at compile time[1] (instead of only at run-time) with the addition of __alloc_size. Fix this by forcing the compiler into not being able to trust the size used following the kmalloc()s. [1] https://lore.kernel.org/lkml/20211005184717.65c6d8eb39350395e387b71f@linux-foundation.org Link: https://lkml.kernel.org/r/20211006181544.1670992-1-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_kasan.c8
-rw-r--r--lib/test_kasan_module.c2
2 files changed, 9 insertions, 1 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index aa8e42250219..5475fe396ff7 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -440,6 +440,7 @@ static void kmalloc_oob_memset_2(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2));
kfree(ptr);
}
@@ -452,6 +453,7 @@ static void kmalloc_oob_memset_4(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4));
kfree(ptr);
}
@@ -464,6 +466,7 @@ static void kmalloc_oob_memset_8(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8));
kfree(ptr);
}
@@ -476,6 +479,7 @@ static void kmalloc_oob_memset_16(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16));
kfree(ptr);
}
@@ -488,6 +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(size);
KUNIT_EXPECT_KASAN_FAIL(test,
memset(ptr, 0, size + KASAN_GRANULE_SIZE));
kfree(ptr);
@@ -497,7 +502,7 @@ static void kmalloc_memmove_negative_size(struct kunit *test)
{
char *ptr;
size_t size = 64;
- volatile size_t invalid_size = -2;
+ size_t invalid_size = -2;
/*
* Hardware tag-based mode doesn't check memmove for negative size.
@@ -510,6 +515,7 @@ 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(invalid_size);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
kfree(ptr);
diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c
index 7ebf433edef3..b112cbc835e9 100644
--- a/lib/test_kasan_module.c
+++ b/lib/test_kasan_module.c
@@ -35,6 +35,8 @@ static noinline void __init copy_user_test(void)
return;
}
+ OPTIMIZER_HIDE_VAR(size);
+
pr_info("out-of-bounds in copy_from_user()\n");
unused = copy_from_user(kmem, usermem, size + 1);