diff options
author | Vitaly Chikunov <vt@altlinux.org> | 2019-04-11 18:51:15 +0300 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2019-04-18 17:15:02 +0300 |
commit | c7381b01287240abe942a081729203e26782d981 (patch) | |
tree | f70bd59c5b8b110b9116d1660d5fe03033ed3596 /crypto/asymmetric_keys | |
parent | 3ecc97259934489e7e03cbeb1d70f6a23cccb3ae (diff) | |
download | linux-c7381b01287240abe942a081729203e26782d981.tar.xz |
crypto: akcipher - new verify API for public key algorithms
Previous akcipher .verify() just `decrypts' (using RSA encrypt which is
using public key) signature to uncover message hash, which was then
compared in upper level public_key_verify_signature() with the expected
hash value, which itself was never passed into verify().
This approach was incompatible with EC-DSA family of algorithms,
because, to verify a signature EC-DSA algorithm also needs a hash value
as input; then it's used (together with a signature divided into halves
`r||s') to produce a witness value, which is then compared with `r' to
determine if the signature is correct. Thus, for EC-DSA, nor
requirements of .verify() itself, nor its output expectations in
public_key_verify_signature() wasn't sufficient.
Make improved .verify() call which gets hash value as input and produce
complete signature check without any output besides status.
Now for the top level verification only crypto_akcipher_verify() needs
to be called and its return value inspected.
Make sure that `digest' is in kmalloc'd memory (in place of `output`) in
{public,tpm}_key_verify_signature() as insisted by Herbert Xu, and will
be changed in the following commit.
Cc: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/asymmetric_keys')
-rw-r--r-- | crypto/asymmetric_keys/asym_tpm.c | 34 | ||||
-rw-r--r-- | crypto/asymmetric_keys/public_key.c | 34 |
2 files changed, 20 insertions, 48 deletions
diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c index 5d4c270463f6..4e5b6fb57a94 100644 --- a/crypto/asymmetric_keys/asym_tpm.c +++ b/crypto/asymmetric_keys/asym_tpm.c @@ -744,12 +744,11 @@ static int tpm_key_verify_signature(const struct key *key, struct crypto_wait cwait; struct crypto_akcipher *tfm; struct akcipher_request *req; - struct scatterlist sig_sg, digest_sg; + struct scatterlist src_sg[2]; char alg_name[CRYPTO_MAX_ALG_NAME]; uint8_t der_pub_key[PUB_KEY_BUF_SIZE]; uint32_t der_pub_key_len; - void *output; - unsigned int outlen; + void *digest; int ret; pr_devel("==>%s()\n", __func__); @@ -782,35 +781,22 @@ static int tpm_key_verify_signature(const struct key *key, goto error_free_tfm; ret = -ENOMEM; - outlen = crypto_akcipher_maxsize(tfm); - output = kmalloc(outlen, GFP_KERNEL); - if (!output) + digest = kmemdup(sig->digest, sig->digest_size, GFP_KERNEL); + if (!digest) goto error_free_req; - sg_init_one(&sig_sg, sig->s, sig->s_size); - sg_init_one(&digest_sg, output, outlen); - akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size, - outlen); + 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); + akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, + sig->digest_size); crypto_init_wait(&cwait); akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, crypto_req_done, &cwait); - - /* Perform the verification calculation. This doesn't actually do the - * verification, but rather calculates the hash expected by the - * signature and returns that to us. - */ ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); - if (ret) - goto out_free_output; - - /* Do the actual verification step. */ - if (req->dst_len != sig->digest_size || - memcmp(sig->digest, output, sig->digest_size) != 0) - ret = -EKEYREJECTED; -out_free_output: - kfree(output); + kfree(digest); error_free_req: akcipher_request_free(req); error_free_tfm: diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index f5d85b47fcc6..0c069fe8a59c 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -227,10 +227,9 @@ int public_key_verify_signature(const struct public_key *pkey, struct crypto_wait cwait; struct crypto_akcipher *tfm; struct akcipher_request *req; - struct scatterlist sig_sg, digest_sg; + struct scatterlist src_sg[2]; char alg_name[CRYPTO_MAX_ALG_NAME]; - void *output; - unsigned int outlen; + void *digest; int ret; pr_devel("==>%s()\n", __func__); @@ -264,35 +263,22 @@ int public_key_verify_signature(const struct public_key *pkey, goto error_free_req; ret = -ENOMEM; - outlen = crypto_akcipher_maxsize(tfm); - output = kmalloc(outlen, GFP_KERNEL); - if (!output) + digest = kmemdup(sig->digest, sig->digest_size, GFP_KERNEL); + if (!digest) goto error_free_req; - sg_init_one(&sig_sg, sig->s, sig->s_size); - sg_init_one(&digest_sg, output, outlen); - akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size, - outlen); + 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); + akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, + sig->digest_size); crypto_init_wait(&cwait); akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, crypto_req_done, &cwait); - - /* Perform the verification calculation. This doesn't actually do the - * verification, but rather calculates the hash expected by the - * signature and returns that to us. - */ ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); - if (ret) - goto out_free_output; - - /* Do the actual verification step. */ - if (req->dst_len != sig->digest_size || - memcmp(sig->digest, output, sig->digest_size) != 0) - ret = -EKEYREJECTED; -out_free_output: - kfree(output); + kfree(digest); error_free_req: akcipher_request_free(req); error_free_tfm: |