[RFC PATCH 05/12] KEYS: Generalise x509_request_asymmetric_key() [ver #2]

[David Howells]

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.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

 crypto/asymmetric_keys/asymmetric_keys.h |    2 +
 crypto/asymmetric_keys/asymmetric_type.c |   42 +++++++++++++++---------------
 crypto/asymmetric_keys/pkcs7_trust.c     |   19 ++++++--------
 crypto/asymmetric_keys/x509_public_key.c |    5 +---
 include/keys/asymmetric-type.h           |    8 +++---
 5 files changed, 37 insertions(+), 39 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/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index c4d66cd82860..6600181d5d01 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -35,21 +35,20 @@ static LIST_HEAD(asymmetric_key_parsers);
 static DECLARE_RWSEM(asymmetric_key_parsers_sem);
 
 /**
- * x509_request_asymmetric_key - Request a key by X.509 certificate params.
+ * find_asymmetric_key - Find 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 *find_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;
@@ -57,12 +56,12 @@ 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>". */
@@ -102,14 +101,15 @@ 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;
 		}
 	}
@@ -121,7 +121,7 @@ reject:
 	key_put(key);
 	return ERR_PTR(-EKEYREJECTED);
 }
-EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
+EXPORT_SYMBOL_GPL(find_asymmetric_key);
 
 /**
  * asymmetric_key_generate_id: Construct an asymmetric key ID
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 36e77cb07bd0..f6a009d88a33 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -51,9 +51,8 @@ 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 = find_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 +83,10 @@ 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 = find_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 +100,8 @@ 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 = find_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/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 2fb594175cef..9c8483ef1cfe 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -213,9 +213,8 @@ static 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 = find_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/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index 735db697c4d2..b38240716d41 100644
--- a/include/keys/asymmetric-type.h
+++ b/include/keys/asymmetric-type.h
@@ -76,10 +76,10 @@ const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
 	return key->payload.data[asym_key_ids];
 }
 
-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 *find_asymmetric_key(struct key *keyring,
+				       const struct asymmetric_key_id *id_0,
+				       const struct asymmetric_key_id *id_1,
+				       bool partial);
 
 /*
  * The payload is at the discretion of the subtype.