[PATCH v8 04/10] KEYS: do not kmemdup digest in {public,tpm}_key_verify_signature

Vitaly Chikunov
2019-03-26T12:59:24Z

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@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org
Signed-off-by: Vitaly Chikunov <vt@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 0c069fe8a59c..33093b7bcc47 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -229,7 +229,6 @@ 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__);
@@ -262,14 +261,9 @@ 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);
@@ -278,7 +272,6 @@ 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