Messages in this thread | | | Subject | Re: [PATCH 7/7] X.509: support OSCCA sm2-with-sm3 certificate verification | From | Tianjia Zhang <> | Date | Tue, 17 Mar 2020 14:50:53 +0800 |
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On 2020/3/17 14:31, Gilad Ben-Yossef wrote: > Hi, > > On Sun, Feb 16, 2020 at 11:00 AM Tianjia Zhang > <tianjia.zhang@linux.alibaba.com> wrote: >> >> The digital certificate format based on SM2 crypto algorithm as >> specified in GM/T 0015-2012. It was published by State Encryption >> Management Bureau, China. >> >> The method of generating Other User Information is defined as >> ZA=H256(ENTLA || IDA || a || b || xG || yG || xA || yA), it also >> specified in https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02. >> >> The x509 certificate supports sm2-with-sm3 type certificate >> verification. Because certificate verification requires ZA >> in addition to tbs data, ZA also depends on elliptic curve >> parameters and public key data, so you need to access tbs in sig >> and calculate ZA. Finally calculate the digest of the >> signature and complete the verification work. The calculation >> process of ZA is declared in specifications GM/T 0009-2012 >> and GM/T 0003.2-2012. >> >> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> >> --- >> crypto/asymmetric_keys/public_key.c | 61 ++++++++++++++++++++++++ >> crypto/asymmetric_keys/x509_public_key.c | 2 + >> include/crypto/public_key.h | 1 + >> 3 files changed, 64 insertions(+) >> >> diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c >> index d7f43d4ea925..a51b09ee484d 100644 >> --- a/crypto/asymmetric_keys/public_key.c >> +++ b/crypto/asymmetric_keys/public_key.c >> @@ -17,6 +17,11 @@ >> #include <keys/asymmetric-subtype.h> >> #include <crypto/public_key.h> >> #include <crypto/akcipher.h> > > hmmm... ifdefs like these are kind of ugly. > >> +#ifdef CONFIG_CRYPTO_SM2 >> +#include <crypto/sm3_base.h> >> +#include <crypto/sm2.h> >> +#include "x509_parser.h" >> +#endif >> >> MODULE_DESCRIPTION("In-software asymmetric public-key subtype"); >> MODULE_AUTHOR("Red Hat, Inc."); >> @@ -245,6 +250,54 @@ static int software_key_eds_op(struct kernel_pkey_params *params, >> return ret; >> } >> >> +#ifdef CONFIG_CRYPTO_SM2 >> +static int cert_sig_digest_update(const struct public_key_signature *sig, >> + struct crypto_akcipher *tfm_pkey) >> +{ >> + struct x509_certificate *cert = sig->cert; >> + struct crypto_shash *tfm; >> + struct shash_desc *desc; >> + size_t desc_size; >> + unsigned char dgst[SM3_DIGEST_SIZE]; >> + int ret; >> + >> + if (!cert) >> + return -EINVAL; >> + >> + ret = sm2_compute_z_digest(tfm_pkey, SM2_DEFAULT_USERID, >> + SM2_DEFAULT_USERID_LEN, dgst); >> + if (ret) >> + return ret; >> + >> + tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); >> + if (IS_ERR(tfm)) >> + return PTR_ERR(tfm); >> + >> + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); >> + desc = kzalloc(desc_size, GFP_KERNEL); >> + if (!desc) >> + goto error_free_tfm; >> + >> + desc->tfm = tfm; >> + >> + ret = crypto_shash_init(desc); >> + if (ret < 0) >> + goto error_free_desc; >> + >> + ret = crypto_shash_update(desc, dgst, SM3_DIGEST_SIZE); >> + if (ret < 0) >> + goto error_free_desc; >> + >> + ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest); >> + >> +error_free_desc: >> + kfree(desc); >> +error_free_tfm: >> + crypto_free_shash(tfm); >> + return ret; >> +} >> +#endif >> + >> /* >> * Verify a signature using a public key. >> */ >> @@ -298,6 +351,14 @@ int public_key_verify_signature(const struct public_key *pkey, >> if (ret) >> goto error_free_key; >> > > OK, how about you put cert_sig_digest_update() in a separate file that > only gets compiled with CONFIG_CRYPTO_SM2 and have a static inline > version that returns -ENOTSUPP otherwise? > or at least something in this spirit. > Done right it will allow you to drop the ifdefs and make for a much > cleaner code. > >> +#ifdef CONFIG_CRYPTO_SM2 >> + if (strcmp(sig->pkey_algo, "sm2") == 0) { >> + ret = cert_sig_digest_update(sig, tfm); >> + if (ret) >> + goto error_free_key; >> + } >> +#endif >> + >> sg_init_table(src_sg, 2); >> sg_set_buf(&src_sg[0], sig->s, sig->s_size); >> sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); >> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c >> index d964cc82b69c..feccec08b244 100644 >> --- a/crypto/asymmetric_keys/x509_public_key.c >> +++ b/crypto/asymmetric_keys/x509_public_key.c >> @@ -30,6 +30,8 @@ int x509_get_sig_params(struct x509_certificate *cert) >> >> pr_devel("==>%s()\n", __func__); >> >> + sig->cert = cert; >> + >> if (!cert->pub->pkey_algo) >> cert->unsupported_key = true; >> >> diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h >> index 0588ef3bc6ff..27775e617e38 100644 >> --- a/include/crypto/public_key.h >> +++ b/include/crypto/public_key.h >> @@ -44,6 +44,7 @@ struct public_key_signature { >> const char *pkey_algo; >> const char *hash_algo; >> const char *encoding; >> + void *cert; /* For certificate */ >> }; >> >> extern void public_key_signature_free(struct public_key_signature *sig); >> -- >> 2.17.1 >> > >
Hi,
Thanks for your suggestion, it is indeed appropriate to unify the SM2 implementation with the public code, I will implement it.
Thanks, Tianjia
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