Commit c6a771d9 authored by Will Deacon's avatar Will Deacon

arm64: csum: Disable KASAN for do_csum()

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@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 9b4fb5ce
...@@ -14,7 +14,11 @@ static u64 accumulate(u64 sum, u64 data) ...@@ -14,7 +14,11 @@ static u64 accumulate(u64 sum, u64 data)
return tmp + (tmp >> 64); 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; unsigned int offset, shift, sum;
const u64 *ptr; const u64 *ptr;
...@@ -42,7 +46,7 @@ unsigned int do_csum(const unsigned char *buff, int len) ...@@ -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. * odd/even alignment, and means we can ignore it until the very end.
*/ */
shift = offset * 8; shift = offset * 8;
data = READ_ONCE_NOCHECK(*ptr++); data = *ptr++;
#ifdef __LITTLE_ENDIAN #ifdef __LITTLE_ENDIAN
data = (data >> shift) << shift; data = (data >> shift) << shift;
#else #else
...@@ -58,10 +62,10 @@ unsigned int do_csum(const unsigned char *buff, int len) ...@@ -58,10 +62,10 @@ unsigned int do_csum(const unsigned char *buff, int len)
while (unlikely(len > 64)) { while (unlikely(len > 64)) {
__uint128_t tmp1, tmp2, tmp3, tmp4; __uint128_t tmp1, tmp2, tmp3, tmp4;
tmp1 = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); tmp1 = *(__uint128_t *)ptr;
tmp2 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 2)); tmp2 = *(__uint128_t *)(ptr + 2);
tmp3 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 4)); tmp3 = *(__uint128_t *)(ptr + 4);
tmp4 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 6)); tmp4 = *(__uint128_t *)(ptr + 6);
len -= 64; len -= 64;
ptr += 8; ptr += 8;
...@@ -85,7 +89,7 @@ unsigned int do_csum(const unsigned char *buff, int len) ...@@ -85,7 +89,7 @@ unsigned int do_csum(const unsigned char *buff, int len)
__uint128_t tmp; __uint128_t tmp;
sum64 = accumulate(sum64, data); sum64 = accumulate(sum64, data);
tmp = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); tmp = *(__uint128_t *)ptr;
len -= 16; len -= 16;
ptr += 2; ptr += 2;
...@@ -100,7 +104,7 @@ unsigned int do_csum(const unsigned char *buff, int len) ...@@ -100,7 +104,7 @@ unsigned int do_csum(const unsigned char *buff, int len)
} }
if (len > 0) { if (len > 0) {
sum64 = accumulate(sum64, data); sum64 = accumulate(sum64, data);
data = READ_ONCE_NOCHECK(*ptr); data = *ptr;
len -= 8; len -= 8;
} }
/* /*
......
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