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

[Vitaly Chikunov]

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 <dhowe...@redhat.com>
Cc: David Howells <dhowe...@redhat.com>
Cc: keyri...@vger.kernel.org
Signed-off-by: Vitaly Chikunov <v...@altlinux.org>
---
 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