KEYS: Allow authentication data to be stored in an asymmetric key

Allow authentication data to be stored in an asymmetric key in the 4th
element of the key payload and provide a way for it to be destroyed.

For the public key subtype, this will be a public_key_signature struct.

Signed-off-by: David Howells <dhowells@redhat.com>

7 files changed, 43 insertions, 14 deletions

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index 9f2165b27d52..a79d30128821 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -331,7 +331,8 @@ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
         pr_devel("==>%s()\n", __func__);
 
         if (subtype) {
-                subtype->destroy(prep->payload.data[asym_crypto]);
+                subtype->destroy(prep->payload.data[asym_crypto],
+                                 prep->payload.data[asym_auth]);
                 module_put(subtype->owner);
         }
         asymmetric_key_free_kids(kids);
@@ -346,13 +347,15 @@ static void asymmetric_key_destroy(struct key *key)
         struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
         struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
         void *data = key->payload.data[asym_crypto];
+        void *auth = key->payload.data[asym_auth];
 
         key->payload.data[asym_crypto] = NULL;
         key->payload.data[asym_subtype] = NULL;
         key->payload.data[asym_key_ids] = NULL;
+        key->payload.data[asym_auth] = NULL;
 
         if (subtype) {
-                subtype->destroy(data);
+                subtype->destroy(data, auth);
                 module_put(subtype->owner);
         }
 
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 0f8b264b3961..fd76b5fc3b3a 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -39,15 +39,23 @@ static void public_key_describe(const struct key *asymmetric_key,
 /*
  * Destroy a public key algorithm key.
  */
-void public_key_destroy(void *payload)
+void public_key_free(struct public_key *key)
 {
-        struct public_key *key = payload;
-
-        if (key)
+        if (key) {
                 kfree(key->key);
-        kfree(key);
+                kfree(key);
+        }
+}
+EXPORT_SYMBOL_GPL(public_key_free);
+
+/*
+ * Destroy a public key algorithm key.
+ */
+static void public_key_destroy(void *payload0, void *payload3)
+{
+        public_key_free(payload0);
+        public_key_signature_free(payload3);
 }
-EXPORT_SYMBOL_GPL(public_key_destroy);
 
 struct public_key_completion {
         struct completion completion;
diff --git a/crypto/asymmetric_keys/signature.c b/crypto/asymmetric_keys/signature.c
index 004d5fc8e56b..3beee3976ed5 100644
--- a/crypto/asymmetric_keys/signature.c
+++ b/crypto/asymmetric_keys/signature.c
@@ -15,9 +15,23 @@
 #include <keys/asymmetric-subtype.h>
 #include <linux/export.h>
 #include <linux/err.h>
+#include <linux/slab.h>
 #include <crypto/public_key.h>
 #include "asymmetric_keys.h"
 
+/*
+ * Destroy a public key signature.
+ */
+void public_key_signature_free(struct public_key_signature *sig)
+{
+        if (sig) {
+                kfree(sig->s);
+                kfree(sig->digest);
+                kfree(sig);
+        }
+}
+EXPORT_SYMBOL_GPL(public_key_signature_free);
+
 /**
  * verify_signature - Initiate the use of an asymmetric key to verify a signature
  * @key: The asymmetric key to verify against
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 4a29bac70060..05251c7f9a03 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -47,7 +47,7 @@ struct x509_parse_context {
 void x509_free_certificate(struct x509_certificate *cert)
 {
         if (cert) {
-                public_key_destroy(cert->pub);
+                public_key_free(cert->pub);
                 kfree(cert->issuer);
                 kfree(cert->subject);
                 kfree(cert->id);
diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
index aa730ea7faf8..19f557ca50ba 100644
--- a/include/crypto/public_key.h
+++ b/include/crypto/public_key.h
@@ -41,7 +41,7 @@ struct public_key {
         const char *pkey_algo;
 };
 
-extern void public_key_destroy(void *payload);
+extern void public_key_free(struct public_key *key);
 
 /*
  * Public key cryptography signature data
@@ -55,7 +55,10 @@ struct public_key_signature {
         const char *hash_algo;
 };
 
+extern void public_key_signature_free(struct public_key_signature *sig);
+
 extern struct asymmetric_key_subtype public_key_subtype;
+
 struct key;
 extern int verify_signature(const struct key *key,
                             const struct public_key_signature *sig);
diff --git a/include/keys/asymmetric-subtype.h b/include/keys/asymmetric-subtype.h
index 4915d40d3c3c..2480469ce8fb 100644
--- a/include/keys/asymmetric-subtype.h
+++ b/include/keys/asymmetric-subtype.h
@@ -32,7 +32,7 @@ struct asymmetric_key_subtype {
         void (*describe)(const struct key *key, struct seq_file *m);
 
         /* Destroy a key of this subtype */
-        void (*destroy)(void *payload);
+        void (*destroy)(void *payload_crypto, void *payload_auth);
 
         /* Verify the signature on a key of this subtype (optional) */
         int (*verify_signature)(const struct key *key,
diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index 59c1df9cf922..70a8775bb444 100644
--- a/include/keys/asymmetric-type.h
+++ b/include/keys/asymmetric-type.h
@@ -23,9 +23,10 @@ extern struct key_type key_type_asymmetric;
  * follows:
  */
 enum asymmetric_payload_bits {
-        asym_crypto,
-        asym_subtype,
-        asym_key_ids,
+        asym_crypto,            /* The data representing the key */
+        asym_subtype,           /* Pointer to an asymmetric_key_subtype struct */
+        asym_key_ids,           /* Pointer to an asymmetric_key_ids struct */
+        asym_auth               /* The key's authorisation (signature, parent key ID) */
 };
 
 /*