do_csum() over-reads the source buffer and therefore abuses
READ_ONCE_NOCHECK() to avoid tripping up KASAN. In preparation for
READ_ONCE_NOCHECK() becoming a macro, and therefore losing its
'__no_sanitize_address' annotation, just annotate do_csum() explicitly
and fall back to normal loads.
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/lib/csum.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/lib/csum.c b/arch/arm64/lib/csum.c
index 60eccae2abad..78b87a64ca0a 100644
--- a/arch/arm64/lib/csum.c
+++ b/arch/arm64/lib/csum.c
@@ -14,7 +14,11 @@ static u64 accumulate(u64 sum, u64 data)
return tmp + (tmp >> 64);
}
-unsigned int do_csum(const unsigned char *buff, int len)
+/*
+ * We over-read the buffer and this makes KASAN unhappy. Instead, disable
+ * instrumentation and call kasan explicitly.
+ */
+unsigned int __no_sanitize_address do_csum(const unsigned char *buff, int len)
{
unsigned int offset, shift, sum;
const u64 *ptr;
@@ -42,7 +46,7 @@ unsigned int do_csum(const unsigned char *buff, int len)
* odd/even alignment, and means we can ignore it until the very end.
*/
shift = offset * 8;
- data = READ_ONCE_NOCHECK(*ptr++);
+ data = *ptr++;
#ifdef __LITTLE_ENDIAN
data = (data >> shift) << shift;
#else
@@ -58,10 +62,10 @@ unsigned int do_csum(const unsigned char *buff, int len)
while (unlikely(len > 64)) {
__uint128_t tmp1, tmp2, tmp3, tmp4;
- tmp1 = READ_ONCE_NOCHECK(*(__uint128_t *)ptr);
- tmp2 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 2));
- tmp3 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 4));
- tmp4 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 6));
+ tmp1 = *(__uint128_t *)ptr;
+ tmp2 = *(__uint128_t *)(ptr + 2);
+ tmp3 = *(__uint128_t *)(ptr + 4);
+ tmp4 = *(__uint128_t *)(ptr + 6);
len -= 64;
ptr += 8;
@@ -85,7 +89,7 @@ unsigned int do_csum(const unsigned char *buff, int len)
__uint128_t tmp;
sum64 = accumulate(sum64, data);
- tmp = READ_ONCE_NOCHECK(*(__uint128_t *)ptr);
+ tmp = *(__uint128_t *)ptr;
len -= 16;
ptr += 2;
@@ -100,7 +104,7 @@ unsigned int do_csum(const unsigned char *buff, int len)
}
if (len > 0) {
sum64 = accumulate(sum64, data);
- data = READ_ONCE_NOCHECK(*ptr);
+ data = *ptr;
len -= 8;
}
/*
--
2.26.1.301.g55bc3eb7cb9-goog
