Re: [RFC PATCH 14/20] KEYS: Generalise x509_request_asymmetric_key() [ver #2]

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

On Tue, 2016-01-19 at 11:32 +0000, David Howells wrote:
> Generalise x509_request_asymmetric_key().  It doesn't really have any
> dependencies on X.509 features as it uses generalised IDs and the
> public_key structs that contain data extracted from X.509.

CC'ing Dmitry Kasatkin.

This patch also renames the digsig version of request_asymmetric_keys().

Mimi

> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
> 
>  crypto/asymmetric_keys/asymmetric_keys.h  |    2 +
>  crypto/asymmetric_keys/pkcs7_trust.c      |   22 +++++------
>  crypto/asymmetric_keys/public_key_trust.c |   60 +++++++++++++----------------
>  include/crypto/public_key.h               |    8 ++--
>  security/integrity/digsig_asymmetric.c    |    5 +-
>  5 files changed, 46 insertions(+), 51 deletions(-)
> 
> diff --git a/crypto/asymmetric_keys/asymmetric_keys.h b/crypto/asymmetric_keys/asymmetric_keys.h
> index 1d450b580245..ca8e9ac34ce6 100644
> --- a/crypto/asymmetric_keys/asymmetric_keys.h
> +++ b/crypto/asymmetric_keys/asymmetric_keys.h
> @@ -9,6 +9,8 @@
>   * 2 of the Licence, or (at your option) any later version.
>   */
> 
> +#include <keys/asymmetric-type.h>
> +
>  extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id);
> 
>  extern int __asymmetric_key_hex_to_key_id(const char *id,
> diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
> index 400ef359448a..8760bc566902 100644
> --- a/crypto/asymmetric_keys/pkcs7_trust.c
> +++ b/crypto/asymmetric_keys/pkcs7_trust.c
> @@ -51,9 +51,9 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
>  		/* Look to see if this certificate is present in the trusted
>  		 * keys.
>  		 */
> -		key = x509_request_asymmetric_key(trust_keyring,
> -						  x509->id, x509->skid,
> -						  false);
> +		key = request_asymmetric_key(trust_keyring,
> +					     x509->id, x509->skid,
> +					     false);
>  		if (!IS_ERR(key)) {
>  			/* One of the X.509 certificates in the PKCS#7 message
>  			 * is apparently the same as one we already trust.
> @@ -84,10 +84,10 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
>  	 * trusted keys.
>  	 */
>  	if (last && (last->sig->auth_ids[0] || last->sig->auth_ids[1])) {
> -		key = x509_request_asymmetric_key(trust_keyring,
> -						  last->sig->auth_ids[0],
> -						  last->sig->auth_ids[1],
> -						  false);
> +		key = request_asymmetric_key(trust_keyring,
> +					     last->sig->auth_ids[0],
> +					     last->sig->auth_ids[1],
> +					     false);
>  		if (!IS_ERR(key)) {
>  			x509 = last;
>  			pr_devel("sinfo %u: Root cert %u signer is key %x\n",
> @@ -101,10 +101,10 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
>  	/* As a last resort, see if we have a trusted public key that matches
>  	 * the signed info directly.
>  	 */
> -	key = x509_request_asymmetric_key(trust_keyring,
> -					  sinfo->sig->auth_ids[0],
> -					  NULL,
> -					  false);
> +	key = request_asymmetric_key(trust_keyring,
> +				     sinfo->sig->auth_ids[0],
> +				     NULL,
> +				     false);
>  	if (!IS_ERR(key)) {
>  		pr_devel("sinfo %u: Direct signer is key %x\n",
>  			 sinfo->index, key_serial(key));
> diff --git a/crypto/asymmetric_keys/public_key_trust.c b/crypto/asymmetric_keys/public_key_trust.c
> index 9febe612e659..afb2a3eb583a 100644
> --- a/crypto/asymmetric_keys/public_key_trust.c
> +++ b/crypto/asymmetric_keys/public_key_trust.c
> @@ -1,6 +1,6 @@
> -/* Instantiate a public key crypto key from an X.509 Certificate
> +/* Validate one public key against another to determine trust chaining.
>   *
> - * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
> + * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
>   * Written by David Howells (dhowells@redhat.com)
>   *
>   * This program is free software; you can redistribute it and/or
> @@ -9,17 +9,10 @@
>   * 2 of the Licence, or (at your option) any later version.
>   */
> 
> -#define pr_fmt(fmt) "X.509: "fmt
> -#include <linux/module.h>
> +#define pr_fmt(fmt) "PKEY: "fmt
>  #include <linux/kernel.h>
>  #include <linux/slab.h>
>  #include <linux/err.h>
> -#include <linux/mpi.h>
> -#include <linux/asn1_decoder.h>
> -#include <keys/asymmetric-subtype.h>
> -#include <keys/asymmetric-parser.h>
> -#include <keys/system_keyring.h>
> -#include <crypto/hash.h>
>  #include "asymmetric_keys.h"
>  #include "public_key.h"
>  #include "x509_parser.h"
> @@ -63,21 +56,20 @@ __setup("ca_keys=", ca_keys_setup);
>  #endif
> 
>  /**
> - * x509_request_asymmetric_key - Request a key by X.509 certificate params.
> + * request_asymmetric_key - Request a key by ID.
>   * @keyring: The keys to search.
> - * @id: The issuer & serialNumber to look for or NULL.
> - * @skid: The subjectKeyIdentifier to look for or NULL.
> + * @id_0: The first ID to look for or NULL.
> + * @id_1: The second ID to look for or NULL.
>   * @partial: Use partial match if true, exact if false.
>   *
>   * Find a key in the given keyring by identifier.  The preferred identifier is
> - * the issuer + serialNumber and the fallback identifier is the
> - * subjectKeyIdentifier.  If both are given, the lookup is by the former, but
> - * the latter must also match.
> + * the id_0 and the fallback identifier is the id_1.  If both are given, the
> + * lookup is by the former, but the latter must also match.
>   */
> -struct key *x509_request_asymmetric_key(struct key *keyring,
> -					const struct asymmetric_key_id *id,
> -					const struct asymmetric_key_id *skid,
> -					bool partial)
> +struct key *request_asymmetric_key(struct key *keyring,
> +				   const struct asymmetric_key_id *id_0,
> +				   const struct asymmetric_key_id *id_1,
> +				   bool partial)
>  {
>  	struct key *key;
>  	key_ref_t ref;
> @@ -85,12 +77,12 @@ struct key *x509_request_asymmetric_key(struct key *keyring,
>  	char *req, *p;
>  	int len;
> 
> -	if (id) {
> -		lookup = id->data;
> -		len = id->len;
> +	if (id_0) {
> +		lookup = id_0->data;
> +		len = id_0->len;
>  	} else {
> -		lookup = skid->data;
> -		len = skid->len;
> +		lookup = id_1->data;
> +		len = id_1->len;
>  	}
> 
>  	/* Construct an identifier "id:<keyid>". */
> @@ -130,14 +122,15 @@ struct key *x509_request_asymmetric_key(struct key *keyring,
>  	}
> 
>  	key = key_ref_to_ptr(ref);
> -	if (id && skid) {
> +	if (id_0 && id_1) {
>  		const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
> -		if (!kids->id[1]) {
> -			pr_debug("issuer+serial match, but expected SKID missing\n");
> +
> +		if (!kids->id[0]) {
> +			pr_debug("First ID matches, but second is missing\n");
>  			goto reject;
>  		}
> -		if (!asymmetric_key_id_same(skid, kids->id[1])) {
> -			pr_debug("issuer+serial match, but SKID does not\n");
> +		if (!asymmetric_key_id_same(id_1, kids->id[1])) {
> +			pr_debug("First ID matches, but second does not\n");
>  			goto reject;
>  		}
>  	}
> @@ -149,7 +142,7 @@ reject:
>  	key_put(key);
>  	return ERR_PTR(-EKEYREJECTED);
>  }
> -EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
> +EXPORT_SYMBOL_GPL(request_asymmetric_key);
> 
>  /*
>   * Check the new certificate against the ones in the trust keyring.  If one of
> @@ -177,9 +170,8 @@ int x509_validate_trust(struct x509_certificate *cert,
>  	if (cert->unsupported_sig)
>  		return -ENOPKG;
> 
> -	key = x509_request_asymmetric_key(trust_keyring,
> -					  sig->auth_ids[0], sig->auth_ids[1],
> -					  false);
> +	key = request_asymmetric_key(trust_keyring,
> +				     sig->auth_ids[0], sig->auth_ids[1], false);
>  	if (IS_ERR(key))
>  		return PTR_ERR(key);
> 
> diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
> index ed86bfb23e89..eaaf261d398a 100644
> --- a/include/crypto/public_key.h
> +++ b/include/crypto/public_key.h
> @@ -102,9 +102,9 @@ extern int verify_signature(const struct key *key,
>  			    const struct public_key_signature *sig);
> 
>  struct asymmetric_key_id;
> -extern struct key *x509_request_asymmetric_key(struct key *keyring,
> -					       const struct asymmetric_key_id *id,
> -					       const struct asymmetric_key_id *skid,
> -					       bool partial);
> +extern struct key *request_asymmetric_key(struct key *keyring,
> +					  const struct asymmetric_key_id *id_0,
> +					  const struct asymmetric_key_id *id_1,
> +					  bool partial);
> 
>  #endif /* _LINUX_PUBLIC_KEY_H */
> diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
> index 5ade2a7517a6..be1af41b5c2a 100644
> --- a/security/integrity/digsig_asymmetric.c
> +++ b/security/integrity/digsig_asymmetric.c
> @@ -24,7 +24,8 @@
>  /*
>   * Request an asymmetric key.
>   */
> -static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid)
> +static struct key *ds_request_asymmetric_key(struct key *keyring,
> +					     uint32_t keyid)
>  {
>  	struct key *key;
>  	char name[12];
> @@ -97,7 +98,7 @@ int asymmetric_verify(struct key *keyring, const char *sig,
>  	if (hdr->hash_algo >= PKEY_HASH__LAST)
>  		return -ENOPKG;
> 
> -	key = request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid));
> +	key = ds_request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid));
>  	if (IS_ERR(key))
>  		return PTR_ERR(key);
> 
> 
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