From: Ard Biesheuvel <ard.biesheuvel@linaro.org> To: linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au, linux-arm-kernel@lists.infradead.org Cc: xiakaixu@huawei.com, Ard Biesheuvel <ard.biesheuvel@linaro.org> Subject: [PATCH 2/2] crypto: arm64/aes-ctr: fix NULL dereference in tail processing Date: Tue, 13 Sep 2016 09:48:53 +0100 [thread overview] Message-ID: <1473756533-21078-2-git-send-email-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <1473756533-21078-1-git-send-email-ard.biesheuvel@linaro.org> The AES-CTR glue code avoids calling into the blkcipher API for the tail portion of the walk, by comparing the remainder of walk.nbytes modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight into the tail processing block if they are equal. This tail processing block checks whether nbytes != 0, and does nothing otherwise. However, in case of an allocation failure in the blkcipher layer, we may enter this code with walk.nbytes == 0, while nbytes > 0. In this case, we should not dereference the source and destination pointers, since they may be NULL. So instead of checking for nbytes != 0, check for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in non-error conditions. Fixes: 49788fe2a128 ("arm64/crypto: AES-ECB/CBC/CTR/XTS using ARMv8 NEON and Crypto Extensions") Reported-by: xiakaixu <xiakaixu@huawei.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm64/crypto/aes-glue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c index 5c888049d061..6b2aa0fd6cd0 100644 --- a/arch/arm64/crypto/aes-glue.c +++ b/arch/arm64/crypto/aes-glue.c @@ -216,7 +216,7 @@ static int ctr_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE); } - if (nbytes) { + if (walk.nbytes % AES_BLOCK_SIZE) { u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE; u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE; u8 __aligned(8) tail[AES_BLOCK_SIZE]; -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: ard.biesheuvel@linaro.org (Ard Biesheuvel) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/2] crypto: arm64/aes-ctr: fix NULL dereference in tail processing Date: Tue, 13 Sep 2016 09:48:53 +0100 [thread overview] Message-ID: <1473756533-21078-2-git-send-email-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <1473756533-21078-1-git-send-email-ard.biesheuvel@linaro.org> The AES-CTR glue code avoids calling into the blkcipher API for the tail portion of the walk, by comparing the remainder of walk.nbytes modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight into the tail processing block if they are equal. This tail processing block checks whether nbytes != 0, and does nothing otherwise. However, in case of an allocation failure in the blkcipher layer, we may enter this code with walk.nbytes == 0, while nbytes > 0. In this case, we should not dereference the source and destination pointers, since they may be NULL. So instead of checking for nbytes != 0, check for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in non-error conditions. Fixes: 49788fe2a128 ("arm64/crypto: AES-ECB/CBC/CTR/XTS using ARMv8 NEON and Crypto Extensions") Reported-by: xiakaixu <xiakaixu@huawei.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm64/crypto/aes-glue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c index 5c888049d061..6b2aa0fd6cd0 100644 --- a/arch/arm64/crypto/aes-glue.c +++ b/arch/arm64/crypto/aes-glue.c @@ -216,7 +216,7 @@ static int ctr_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE); } - if (nbytes) { + if (walk.nbytes % AES_BLOCK_SIZE) { u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE; u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE; u8 __aligned(8) tail[AES_BLOCK_SIZE]; -- 2.7.4
next prev parent reply other threads:[~2016-09-13 8:49 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-09-13 8:48 [PATCH 1/2] crypto: arm/aes-ctr: fix NULL dereference in tail processing Ard Biesheuvel 2016-09-13 8:48 ` Ard Biesheuvel 2016-09-13 8:48 ` Ard Biesheuvel [this message] 2016-09-13 8:48 ` [PATCH 2/2] crypto: arm64/aes-ctr: " Ard Biesheuvel 2016-09-13 12:43 ` [PATCH 1/2] crypto: arm/aes-ctr: " Herbert Xu 2016-09-13 12:43 ` Herbert Xu
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