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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-05-17 09:47:44 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-05-17 09:47:44 +0200
commitd8218b0de51f36f01ed67731ccf174059a33bb1e (patch)
treeb38b8856852ab651c4297c33ba47a49ca4dde419 /lib/test_kasan.c
parent76e78f3df8f5d21b1a85f770fa92a1fd211e429b (diff)
parentd07f6ca923ea0927a1024dfccafc5b53b61cfecc (diff)
Merge 5.13-rc2 into staging-next
We need the staging and iio fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/test_kasan.c')
-rw-r--r--lib/test_kasan.c29
1 files changed, 23 insertions, 6 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index dc05cfc2d12f..cacbbbdef768 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -654,8 +654,20 @@ static char global_array[10];
static void kasan_global_oob(struct kunit *test)
{
- volatile int i = 3;
- char *p = &global_array[ARRAY_SIZE(global_array) + i];
+ /*
+ * Deliberate out-of-bounds access. To prevent CONFIG_UBSAN_LOCAL_BOUNDS
+ * from failing here and panicing the kernel, access the array via a
+ * volatile pointer, which will prevent the compiler from being able to
+ * determine the array bounds.
+ *
+ * This access uses a volatile pointer to char (char *volatile) rather
+ * than the more conventional pointer to volatile char (volatile char *)
+ * because we want to prevent the compiler from making inferences about
+ * the pointer itself (i.e. its array bounds), not the data that it
+ * refers to.
+ */
+ char *volatile array = global_array;
+ char *p = &array[ARRAY_SIZE(global_array) + 3];
/* Only generic mode instruments globals. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
@@ -703,8 +715,9 @@ static void ksize_uaf(struct kunit *test)
static void kasan_stack_oob(struct kunit *test)
{
char stack_array[10];
- volatile int i = OOB_TAG_OFF;
- char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
+ /* See comment in kasan_global_oob. */
+ char *volatile array = stack_array;
+ char *p = &array[ARRAY_SIZE(stack_array) + OOB_TAG_OFF];
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
@@ -715,7 +728,9 @@ static void kasan_alloca_oob_left(struct kunit *test)
{
volatile int i = 10;
char alloca_array[i];
- char *p = alloca_array - 1;
+ /* See comment in kasan_global_oob. */
+ char *volatile array = alloca_array;
+ char *p = array - 1;
/* Only generic mode instruments dynamic allocas. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
@@ -728,7 +743,9 @@ static void kasan_alloca_oob_right(struct kunit *test)
{
volatile int i = 10;
char alloca_array[i];
- char *p = alloca_array + i;
+ /* See comment in kasan_global_oob. */
+ char *volatile array = alloca_array;
+ char *p = array + i;
/* Only generic mode instruments dynamic allocas. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);