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From: Jarkko Sakkinen <jarkko@kernel.org>
To: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	Ben Boeckel <me@benboeckel.net>,
	Randy Dunlap <rdunlap@infradead.org>,
	Malte Gell <malte.gell@gmx.de>,
	keyrings@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-kernel@vger.kernel.org, "Lee, Chun-Yi" <jlee@suse.com>
Subject: Re: [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing
Date: Thu, 21 Jan 2021 01:40:48 +0200	[thread overview]
Message-ID: <YAi/gERomykYZqKZ@kernel.org> (raw)
In-Reply-To: <20210120090517.23851-2-jlee@suse.com>

On Wed, Jan 20, 2021 at 05:05:14PM +0800, Lee, Chun-Yi wrote:
> This patch adds the logic for parsing the CodeSign extended key usage
> extension in X.509. The parsing result will be set to the eku flag
> which is carried by public key. It can be used in the PKCS#7
> verification.
> 
> Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com>
> ---
>  crypto/asymmetric_keys/x509_cert_parser.c | 24 ++++++++++++++++++++++++
>  include/crypto/public_key.h               |  1 +
>  include/linux/oid_registry.h              |  5 +++++
>  3 files changed, 30 insertions(+)
> 
> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
> index 52c9b455fc7d..65721313b265 100644
> --- a/crypto/asymmetric_keys/x509_cert_parser.c
> +++ b/crypto/asymmetric_keys/x509_cert_parser.c
> @@ -497,6 +497,8 @@ int x509_process_extension(void *context, size_t hdrlen,
>  	struct x509_parse_context *ctx = context;
>  	struct asymmetric_key_id *kid;
>  	const unsigned char *v = value;
> +	int i = 0;
> +	enum OID oid;
>  
>  	pr_debug("Extension: %u\n", ctx->last_oid);
>  
> @@ -526,6 +528,28 @@ int x509_process_extension(void *context, size_t hdrlen,
>  		return 0;
>  	}
>  
> +	if (ctx->last_oid == OID_extKeyUsage) {
> +		if (v[0] != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ) ||
> +		    v[1] != vlen - 2)
> +			return -EBADMSG;
> +		i += 2;
> +
> +		while (i < vlen) {
> +			/* A 10 bytes EKU OID Octet blob =
> +			 * ASN1_OID + size byte + 8 bytes OID */
> +			if (v[i] != ASN1_OID || v[i + 1] != 8 || (i + 10) > vlen)
> +				return -EBADMSG;
> +
> +			oid = look_up_OID(v + i + 2, v[i + 1]);
> +			if (oid == OID_codeSigning) {
> +				ctx->cert->pub->eku |= EKU_codeSigning;
> +			}
> +			i += 10;
> +		}
> +		pr_debug("extKeyUsage: %d\n", ctx->cert->pub->eku);

With eBPF around, does this make any sense?

/Jarkko

> +		return 0;
> +	}
> +
>  	return 0;
>  }
>  
> diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
> index 948c5203ca9c..07a1b28460a2 100644
> --- a/include/crypto/public_key.h
> +++ b/include/crypto/public_key.h
> @@ -29,6 +29,7 @@ struct public_key {
>  	bool key_is_private;
>  	const char *id_type;
>  	const char *pkey_algo;
> +	unsigned int eku : 9;      /* Extended Key Usage (9-bit) */
>  };
>  
>  extern void public_key_free(struct public_key *key);
> diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> index 4462ed2c18cd..e20e8eb53b21 100644
> --- a/include/linux/oid_registry.h
> +++ b/include/linux/oid_registry.h
> @@ -113,9 +113,14 @@ enum OID {
>  	OID_SM2_with_SM3,		/* 1.2.156.10197.1.501 */
>  	OID_sm3WithRSAEncryption,	/* 1.2.156.10197.1.504 */
>  
> +	/* Extended key purpose OIDs [RFC 5280] */
> +	OID_codeSigning,		/* 1.3.6.1.5.5.7.3.3 */
> +
>  	OID__NR
>  };
>  
> +#define EKU_codeSigning	(1 << 2)
> +
>  extern enum OID look_up_OID(const void *data, size_t datasize);
>  extern int sprint_oid(const void *, size_t, char *, size_t);
>  extern int sprint_OID(enum OID, char *, size_t);
> -- 
> 2.16.4
> 
> 

  reply	other threads:[~2021-01-20 23:45 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20  9:05 [PATCH v4 0/4] Check codeSigning extended key usage extension Lee, Chun-Yi
2021-01-20  9:05 ` [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing Lee, Chun-Yi
2021-01-20 23:40   ` Jarkko Sakkinen [this message]
2021-01-21  4:23     ` joeyli
2021-01-21 14:32       ` Jarkko Sakkinen
2021-01-21 15:23         ` joeyli
2021-01-22 17:28           ` Jarkko Sakkinen
2021-01-27  9:40   ` David Howells
2021-01-20  9:05 ` [PATCH 2/4] PKCS#7: Check codeSigning EKU for kernel module and kexec pe verification Lee, Chun-Yi
2021-01-20  9:05 ` [PATCH 3/4] modsign: Add codeSigning EKU when generating X.509 key generation config Lee, Chun-Yi
2021-01-20  9:05 ` [PATCH 4/4] Documentation/admin-guide/module-signing.rst: add openssl command option example for CodeSign EKU Lee, Chun-Yi
2021-02-22  6:42 [PATCH v4 0/4] Check codeSigning extended key usage extension Lee, Chun-Yi
2021-02-22  6:42 ` [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing Lee, Chun-Yi
2021-03-09  9:10 [PATCH v5 0/4] Check codeSigning extended key usage extension Lee, Chun-Yi
2021-03-09  9:10 ` [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing Lee, Chun-Yi
2021-04-13 14:28   ` Varad Gautam
2021-04-14 16:01     ` joeyli
2021-03-23  3:55 [PATCH v5 0/4] Check codeSigning extended key usage extension Lee, Chun-Yi
2021-03-23  3:55 ` [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing Lee, Chun-Yi
2021-04-09  2:46 [PATCH v5 0/4] Check codeSigning extended key usage extension Lee, Chun-Yi
2021-04-09  2:46 ` [PATCH 1/4] X.509: Add CodeSigning extended key usage parsing Lee, Chun-Yi

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