Re: [dpdk-dev] [PATCH v3] crypto/qat: fix uninitilized compiler warning

["Dybkowski, AdamX" <adamx.dybkowski@intel.com>]

Hi.

I checked how it works on QAT hardware, and it does no harm. All unit tests still pass.
Verified on two QAT-enabled machines.

The question is: should this patch be simplified to just add a call to memset (to zero the digest variable while still keeping it on the stack) at the function begin? And that will be a faster solution in run-time (using the variable on the stack instead of calloc that uses the heap).

Adam

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Feifei Wang
> Sent: Monday, 17 May, 2021 11:07
> To: Griffin, John <john.griffin@intel.com>; Trahe, Fiona
> <fiona.trahe@intel.com>; Jain, Deepak K <deepak.k.jain@intel.com>; Jerin
> Jacob <jerin.jacob@caviumnetworks.com>; Herbert Guan
> <herbert.guan@arm.com>
> Cc: dev@dpdk.org; david.marchand@redhat.com; nd@arm.com; Feifei
> Wang <feifei.wang2@arm.com>; stable@dpdk.org; Ruifeng Wang
> <ruifeng.wang@arm.com>
> Subject: [dpdk-dev] [PATCH v3] crypto/qat: fix uninitilized compiler warning
> 
> In Arm platform, when "RTE_ARCH_ARM64_MEMCPY" is set as true,
> compiler will report variable uninitilized warning:
> 
> ../drivers/crypto/qat/qat_sym_session.c:
> In function ‘partial_hash_compute’:
> ../lib/eal/include/generic/rte_byteorder.h:241:24: warning:
> ‘<U35a0>’ may be used uninitialized in this function
> 	[-Wmaybe-uninitialized]
> 	241 | #define rte_bswap32(x) __builtin_bswap32(x)
> 	...
> 
> This is because "digest" will be initialized by "rte_memcpy" function rather
> than "memcpy" if "RTE_ARCH_ARM64_MEMCPY" is set as true. However,
> compiler cannot know it is initialized by the function.
> 
> To fix this, use "calloc" to initialize "digest".
> 
> Fixes: cd7fc8a84b48 ("eal/arm64: optimize memcpy")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
> v2: add check and free for memory dynamic allocation (David Marchand)
> v3: fix compiler error
> 
>  drivers/crypto/qat/qat_sym_session.c | 27 ++++++++++++++++++---------
>  1 file changed, 18 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/crypto/qat/qat_sym_session.c
> b/drivers/crypto/qat/qat_sym_session.c
> index 231b1640da..105a10957a 100644
> --- a/drivers/crypto/qat/qat_sym_session.c
> +++ b/drivers/crypto/qat/qat_sym_session.c
> @@ -1190,8 +1190,7 @@ static int partial_hash_compute(enum
> icp_qat_hw_auth_algo hash_alg,
>  			uint8_t *data_out)
>  {
>  	int digest_size;
> -	uint8_t digest[qat_hash_get_digest_size(
> -			ICP_QAT_HW_AUTH_ALGO_DELIMITER)];
> +	uint8_t *digest;
>  	uint32_t *hash_state_out_be32;
>  	uint64_t *hash_state_out_be64;
>  	int i;
> @@ -1200,55 +1199,65 @@ static int partial_hash_compute(enum
> icp_qat_hw_auth_algo hash_alg,
>  	if (digest_size <= 0)
>  		return -EFAULT;
> 
> +	digest = calloc(qat_hash_get_digest_size(
> +				ICP_QAT_HW_AUTH_ALGO_DELIMITER),
> sizeof(uint8_t));
> +	if (!digest)
> +		return -ENOMEM;
> +
>  	hash_state_out_be32 = (uint32_t *)data_out;
>  	hash_state_out_be64 = (uint64_t *)data_out;
> 
>  	switch (hash_alg) {
>  	case ICP_QAT_HW_AUTH_ALGO_SHA1:
>  		if (partial_hash_sha1(data_in, digest))
> -			return -EFAULT;
> +			goto fail;
>  		for (i = 0; i < digest_size >> 2; i++, hash_state_out_be32++)
>  			*hash_state_out_be32 =
>  				rte_bswap32(*(((uint32_t *)digest)+i));
>  		break;
>  	case ICP_QAT_HW_AUTH_ALGO_SHA224:
>  		if (partial_hash_sha224(data_in, digest))
> -			return -EFAULT;
> +			goto fail;
>  		for (i = 0; i < digest_size >> 2; i++, hash_state_out_be32++)
>  			*hash_state_out_be32 =
>  				rte_bswap32(*(((uint32_t *)digest)+i));
>  		break;
>  	case ICP_QAT_HW_AUTH_ALGO_SHA256:
>  		if (partial_hash_sha256(data_in, digest))
> -			return -EFAULT;
> +			goto fail;
>  		for (i = 0; i < digest_size >> 2; i++, hash_state_out_be32++)
>  			*hash_state_out_be32 =
>  				rte_bswap32(*(((uint32_t *)digest)+i));
>  		break;
>  	case ICP_QAT_HW_AUTH_ALGO_SHA384:
>  		if (partial_hash_sha384(data_in, digest))
> -			return -EFAULT;
> +			goto fail;
>  		for (i = 0; i < digest_size >> 3; i++, hash_state_out_be64++)
>  			*hash_state_out_be64 =
>  				rte_bswap64(*(((uint64_t *)digest)+i));
>  		break;
>  	case ICP_QAT_HW_AUTH_ALGO_SHA512:
>  		if (partial_hash_sha512(data_in, digest))
> -			return -EFAULT;
> +			goto fail;
>  		for (i = 0; i < digest_size >> 3; i++, hash_state_out_be64++)
>  			*hash_state_out_be64 =
>  				rte_bswap64(*(((uint64_t *)digest)+i));
>  		break;
>  	case ICP_QAT_HW_AUTH_ALGO_MD5:
>  		if (partial_hash_md5(data_in, data_out))
> -			return -EFAULT;
> +			goto fail;
>  		break;
>  	default:
>  		QAT_LOG(ERR, "invalid hash alg %u", hash_alg);
> -		return -EFAULT;
> +		goto fail;
>  	}
> 
> +	free(digest);
>  	return 0;
> +
> +fail:
> +	free(digest);
> +	return -EFAULT;
>  }
>  #define HMAC_IPAD_VALUE	0x36
>  #define HMAC_OPAD_VALUE	0x5c
> --
> 2.25.1