PKCS#7: Use x509_request_asymmetric_key()

pkcs7_request_asymmetric_key() and x509_request_asymmetric_key() do the same
thing, the latter being a copy of the former created by the IMA folks, so drop
the PKCS#7 version as the X.509 location is more general.

Whilst we're at it, rename the arguments of x509_request_asymmetric_key() to
better reflect what the values being passed in are intended to match on an
X.509 cert.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

2 files changed, 25 insertions, 72 deletions

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index b6b045131403..e666eb011a85 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -20,55 +20,6 @@
 #include "public_key.h"
 #include "pkcs7_parser.h"
 
-/*
- * Request an asymmetric key.
- */
-static struct key *pkcs7_request_asymmetric_key(
-        struct key *keyring,
-        const char *signer, size_t signer_len,
-        const char *authority, size_t auth_len)
-{
-        key_ref_t key;
-        char *id;
-
-        kenter(",%zu,,%zu", signer_len, auth_len);
-
-        /* Construct an identifier. */
-        id = kmalloc(signer_len + 2 + auth_len + 1, GFP_KERNEL);
-        if (!id)
-                return ERR_PTR(-ENOMEM);
-
-        memcpy(id, signer, signer_len);
-        id[signer_len + 0] = ':';
-        id[signer_len + 1] = ' ';
-        memcpy(id + signer_len + 2, authority, auth_len);
-        id[signer_len + 2 + auth_len] = 0;
-
-        pr_debug("Look up: \"%s\"\n", id);
-
-        key = keyring_search(make_key_ref(keyring, 1),
-                             &key_type_asymmetric, id);
-        if (IS_ERR(key))
-                pr_debug("Request for module key '%s' err %ld\n",
-                         id, PTR_ERR(key));
-        kfree(id);
-
-        if (IS_ERR(key)) {
-                switch (PTR_ERR(key)) {
-                        /* Hide some search errors */
-                case -EACCES:
-                case -ENOTDIR:
-                case -EAGAIN:
-                        return ERR_PTR(-ENOKEY);
-                default:
-                        return ERR_CAST(key);
-                }
-        }
-
-        pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key_ref_to_ptr(key)));
-        return key_ref_to_ptr(key);
-}
-
 /**
  * Check the trust on one PKCS#7 SignedInfo block.
  */
@@ -98,10 +49,8 @@ int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
                 /* Look to see if this certificate is present in the trusted
                  * keys.
                  */
-                key = pkcs7_request_asymmetric_key(
-                        trust_keyring,
-                        x509->subject, strlen(x509->subject),
-                        x509->fingerprint, strlen(x509->fingerprint));
+                key = x509_request_asymmetric_key(trust_keyring, x509->subject,
+                                                  x509->fingerprint);
                 if (!IS_ERR(key))
                         /* One of the X.509 certificates in the PKCS#7 message
                          * is apparently the same as one we already trust.
@@ -133,10 +82,8 @@ int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
                 return -ENOKEY;
         }
 
-        key = pkcs7_request_asymmetric_key(
-                trust_keyring,
-                last->issuer, strlen(last->issuer),
-                last->authority, strlen(last->authority));
+        key = x509_request_asymmetric_key(trust_keyring, last->issuer,
+                                          last->authority);
         if (IS_ERR(key))
                 return PTR_ERR(key) == -ENOMEM ? -ENOMEM : -ENOKEY;
         x509 = last;
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 4ae982234d78..da1e5fc85346 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -43,35 +43,41 @@ static int __init ca_keys_setup(char *str)
 __setup("ca_keys=", ca_keys_setup);
 #endif
 
-/*
- * Find a key in the given keyring by issuer and authority.
+/**
+ * x509_request_asymmetric_key - Request a key by X.509 certificate params.
+ * @keyring: The keys to search.
+ * @subject: The name of the subject to whom the key belongs.
+ * @key_id: The subject key ID as a hex string.
+ *
+ * Find a key in the given keyring by subject name and key ID.  These might,
+ * for instance, be the issuer name and the authority key ID of an X.509
+ * certificate that needs to be verified.
  */
-static struct key *x509_request_asymmetric_key(struct key *keyring,
-                                               const char *signer,
-                                               const char *authority)
+struct key *x509_request_asymmetric_key(struct key *keyring,
+                                        const char *subject,
+                                        const char *key_id)
 {
         key_ref_t key;
-        size_t signer_len = strlen(signer), auth_len = strlen(authority);
+        size_t subject_len = strlen(subject), key_id_len = strlen(key_id);
         char *id;
 
-        /* Construct an identifier. */
-        id = kmalloc(signer_len + 2 + auth_len + 1, GFP_KERNEL);
+        /* Construct an identifier "<subjname>:<keyid>". */
+        id = kmalloc(subject_len + 2 + key_id_len + 1, GFP_KERNEL);
         if (!id)
                 return ERR_PTR(-ENOMEM);
 
-        memcpy(id, signer, signer_len);
-        id[signer_len + 0] = ':';
-        id[signer_len + 1] = ' ';
-        memcpy(id + signer_len + 2, authority, auth_len);
-        id[signer_len + 2 + auth_len] = 0;
+        memcpy(id, subject, subject_len);
+        id[subject_len + 0] = ':';
+        id[subject_len + 1] = ' ';
+        memcpy(id + subject_len + 2, key_id, key_id_len);
+        id[subject_len + 2 + key_id_len] = 0;
 
         pr_debug("Look up: \"%s\"\n", id);
 
         key = keyring_search(make_key_ref(keyring, 1),
                              &key_type_asymmetric, id);
         if (IS_ERR(key))
-                pr_debug("Request for module key '%s' err %ld\n",
-                         id, PTR_ERR(key));
+                pr_debug("Request for key '%s' err %ld\n", id, PTR_ERR(key));
         kfree(id);
 
         if (IS_ERR(key)) {