Re: [PATCH v7 05/11] KEYS: do not kmemdup digest in {public,tpm}_key_verify_signature

[Vitaly Chikunov]

David,

Can you please Ack this patch, it changes ASYMMETRIC KEYS tree, and
incorporates modifications you requested before.

Thanks,

On Fri, Mar 01, 2019 at 08:59:12PM +0300, Vitaly Chikunov wrote:
> Treat (struct public_key_signature)'s digest same as its signature (s).
> Since digest should be already in the kmalloc'd memory do not kmemdup
> digest value before calling {public,tpm}_key_verify_signature.
> 
> Patch is split from the previous as suggested by Herbert Xu.
> 
> Suggested-by: David Howells <dhowells@xxxxxxxxxx>
> Cc: David Howells <dhowells@xxxxxxxxxx>
> Cc: keyrings@xxxxxxxxxxxxxxx
> Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>
> ---
>  crypto/asymmetric_keys/asym_tpm.c   | 10 +---------
>  crypto/asymmetric_keys/public_key.c |  9 +--------
>  2 files changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
> index 4e5b6fb57a94..402fc34ca044 100644
> --- a/crypto/asymmetric_keys/asym_tpm.c
> +++ b/crypto/asymmetric_keys/asym_tpm.c
> @@ -748,7 +748,6 @@ static int tpm_key_verify_signature(const struct key *key,
>  	char alg_name[CRYPTO_MAX_ALG_NAME];
>  	uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
>  	uint32_t der_pub_key_len;
> -	void *digest;
>  	int ret;
>  
>  	pr_devel("==>%s()\n", __func__);
> @@ -780,14 +779,9 @@ static int tpm_key_verify_signature(const struct key *key,
>  	if (!req)
>  		goto error_free_tfm;
>  
> -	ret = -ENOMEM;
> -	digest = kmemdup(sig->digest, sig->digest_size, GFP_KERNEL);
> -	if (!digest)
> -		goto error_free_req;
> -
>  	sg_init_table(src_sg, 2);
>  	sg_set_buf(&src_sg[0], sig->s, sig->s_size);
> -	sg_set_buf(&src_sg[1], digest, sig->digest_size);
> +	sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
>  	akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
>  				   sig->digest_size);
>  	crypto_init_wait(&cwait);
> @@ -796,8 +790,6 @@ static int tpm_key_verify_signature(const struct key *key,
>  				      crypto_req_done, &cwait);
>  	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
>  
> -	kfree(digest);
> -error_free_req:
>  	akcipher_request_free(req);
>  error_free_tfm:
>  	crypto_free_akcipher(tfm);
> diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
> index 338f2b5352b1..4dcfe281b898 100644
> --- a/crypto/asymmetric_keys/public_key.c
> +++ b/crypto/asymmetric_keys/public_key.c
> @@ -235,7 +235,6 @@ int public_key_verify_signature(const struct public_key *pkey,
>  	struct akcipher_request *req;
>  	struct scatterlist src_sg[2];
>  	char alg_name[CRYPTO_MAX_ALG_NAME];
> -	void *digest;
>  	int ret;
>  
>  	pr_devel("==>%s()\n", __func__);
> @@ -268,14 +267,9 @@ int public_key_verify_signature(const struct public_key *pkey,
>  	if (ret)
>  		goto error_free_req;
>  
> -	ret = -ENOMEM;
> -	digest = kmemdup(sig->digest, sig->digest_size, GFP_KERNEL);
> -	if (!digest)
> -		goto error_free_req;
> -
>  	sg_init_table(src_sg, 2);
>  	sg_set_buf(&src_sg[0], sig->s, sig->s_size);
> -	sg_set_buf(&src_sg[1], digest, sig->digest_size);
> +	sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
>  	akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
>  				   sig->digest_size);
>  	crypto_init_wait(&cwait);
> @@ -284,7 +278,6 @@ int public_key_verify_signature(const struct public_key *pkey,
>  				      crypto_req_done, &cwait);
>  	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
>  
> -	kfree(digest);
>  error_free_req:
>  	akcipher_request_free(req);
>  error_free_tfm:
> -- 
> 2.11.0