From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: [PATCH v4 05/11] arm64: csum: Disable KASAN for do_csum() Date: Tue, 21 Apr 2020 16:15:31 +0100 Message-ID: <20200421151537.19241-6-will@kernel.org> References: <20200421151537.19241-1-will@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200421151537.19241-1-will@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, kernel-team@android.com, Will Deacon , Mark Rutland , Michael Ellerman , Peter Zijlstra , Linus Torvalds , Segher Boessenkool , Christian Borntraeger , Luc Van Oostenryck , Arnd Bergmann , Peter Oberparleiter , Masahiro Yamada , Nick Desaulniers , Robin Murphy List-Id: linux-arch.vger.kernel.org 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 Cc: Robin Murphy Signed-off-by: Will Deacon --- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:34892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726946AbgDUPQB (ORCPT ); Tue, 21 Apr 2020 11:16:01 -0400 From: Will Deacon Subject: [PATCH v4 05/11] arm64: csum: Disable KASAN for do_csum() Date: Tue, 21 Apr 2020 16:15:31 +0100 Message-ID: <20200421151537.19241-6-will@kernel.org> In-Reply-To: <20200421151537.19241-1-will@kernel.org> References: <20200421151537.19241-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, kernel-team@android.com, Will Deacon , Mark Rutland , Michael Ellerman , Peter Zijlstra , Linus Torvalds , Segher Boessenkool , Christian Borntraeger , Luc Van Oostenryck , Arnd Bergmann , Peter Oberparleiter , Masahiro Yamada , Nick Desaulniers , Robin Murphy Message-ID: <20200421151531.SlTAtApF8MlSPxY5Cyp29EG_9PKGgEoEtdQY-ZS9zWU@z> 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 Cc: Robin Murphy Signed-off-by: Will Deacon --- 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