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| author | Will Deacon <will@kernel.org> | 2020-04-14 23:22:47 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-04-15 22:36:41 +0200 |
| commit | c6a771d932332568df9f46a3b53507c578e8c8e8 (patch) | |
| tree | 75d1c03409b023605b61d1e2427479e08f8e302e | |
| parent | fault_inject: Don't rely on "return value" from WRITE_ONCE() (diff) | |
| download | linux-c6a771d932332568df9f46a3b53507c578e8c8e8.tar.xz linux-c6a771d932332568df9f46a3b53507c578e8c8e8.zip | |
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: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/lib/csum.c | 20 |
1 files 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; } /* |