[opensuse-kernel] Re: [PATCH V4 02/15] asymmetric keys: implement EMSA_PKCS1-v1_5-ENCODE in rsa

Hi Phil, First! Thanks for your time to review my patch! 於 一，2013-09-23 於 19:49 +0300，Phil Carmody 提到：

On Sun, Sep 15, 2013 at 08:56:48AM +0800, Lee, Chun-Yi wrote:

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Implement EMSA_PKCS1-v1_5-ENCODE [RFC3447 sec 9.2] in rsa.c. It's the first step of signature generation operation (RSASSA-PKCS1-v1_5-SIGN).

This patch is temporary set emLen to pks->k, and temporary set EM to pks->S for debugging. We will replace the above values to real signature after implement RSASP1.

The naming of EMSA_PKCS1_v1_5_ENCODE and the variables used in this function accord PKCS#1 spec but not follow kernel naming convention, it useful when look at them with spec.

Reference: ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1v2/pkcs1ietffinal.txt Reference: http://www.emc.com/collateral/white-papers/h11300-pkcs-1v2-2-rsa-cryptograph...

V2:

You're now at V4.

The V4 is for whole patchset, I didn't do any modify in this patch in this version. The version define maybe confuse between separate and whole patchset, I will avoid it.

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- Clean up naming of variable: replace _EM by EM, replace EM by EM_tmp. - Add comment to EMSA_PKCS1-v1_5-ENCODE function.

Cc: Pavel Machek Reviewed-by: Jiri Kosina Signed-off-by: Lee, Chun-Yi --- crypto/asymmetric_keys/rsa.c | 163 +++++++++++++++++++++++++++++++++++++++++- include/crypto/public_key.h | 2 + 2 files changed, 164 insertions(+), 1 deletions(-)

diff --git a/crypto/asymmetric_keys/rsa.c b/crypto/asymmetric_keys/rsa.c index 47f3be4..352ba45 100644 --- a/crypto/asymmetric_keys/rsa.c +++ b/crypto/asymmetric_keys/rsa.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "public_key.h" #include "private_key.h"

@@ -152,6 +153,132 @@ static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) }

/* + * EMSA_PKCS1-v1_5-ENCODE [RFC3447 sec 9.2] + * @M: message to be signed, an octet string + * @emLen: intended length in octets of the encoded message + * @hash_algo: hash function (option) + * @hash: true means hash M, otherwise M is already a digest + * @EM: encoded message, an octet string of length emLen + * + * This function is a implementation of the EMSA-PKCS1-v1_5 encoding operation + * in RSA PKCS#1 spec. It used by the signautre generation operation of + * RSASSA-PKCS1-v1_5 to encode message M to encoded message EM. + * + * The variables used in this function accord PKCS#1 spec but not follow kernel + * naming convention, it useful when look at them with spec. + */ +static int EMSA_PKCS1_v1_5_ENCODE(const u8 *M, size_t emLen, + enum pkey_hash_algo hash_algo, const bool hash, + u8 **EM, struct public_key_signature *pks) +{ + u8 *digest; + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t digest_size, desc_size; + size_t tLen; + u8 *T, *PS, *EM_tmp; + int i, ret; + + pr_info("EMSA_PKCS1_v1_5_ENCODE start\n"); + + if (!RSA_ASN1_templates[hash_algo].data) + ret = -ENOTSUPP;

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+ else + pks->pkey_hash_algo = hash_algo; + + /* 1) Apply the hash function to the message M to produce a hash value H */ + tfm = crypto_alloc_shash(pkey_hash_algo[hash_algo], 0, 0); + if (IS_ERR(tfm)) + return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm); + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + digest_size = crypto_shash_digestsize(tfm); + + ret = -ENOMEM;

The earlier "ret = -ENOTSUPP;" is either unused because you return at the IS_ERR, or unused because you overwrite it here. I'm a little disappointed that the compiler didn't recognise that something was assigned to a value that is never used.

Phil

Yes, Dmitry also pointed out this issue, I should not go on the hash process if the hash algorithm didn't support. I will change fix this problem in next version. Thanks a lot! Joey Lee -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org