KEYS: Preparse match data

Preparse the match data.  This provides several advantages:

 (1) The preparser can reject invalid criteria up front.

 (2) The preparser can convert the criteria to binary data if necessary (the
     asymmetric key type really wants to do binary comparison of the key IDs).

 (3) The preparser can set the type of search to be performed.  This means
     that it's not then a one-off setting in the key type.

 (4) The preparser can set an appropriate comparator function.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

1 files changed, 30 insertions, 1 deletions

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index eb8cd46..f666b4e 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -59,9 +59,11 @@ EXPORT_SYMBOL_GPL(asymmetric_keyid_match);
  *	"id:<id>"	- request a key matching the ID
  *	"<subtype>:<id>" - request a key of a subtype
  */
-static int asymmetric_key_match(const struct key *key, const void *description)
+static int asymmetric_key_match(const struct key *key,
+				const struct key_match_data *match_data)
 {
 	const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+	const char *description = match_data->raw_data;
 	const char *spec = description;
 	const char *id;
 	ptrdiff_t speclen;
@@ -94,6 +96,31 @@ static int asymmetric_key_match(const struct key *key, const void *description)
 }
 
 /*
+ * Preparse the match criterion.  If we don't set lookup_type and cmp,
+ * the default will be an exact match on the key description.
+ *
+ * There are some specifiers for matching key IDs rather than by the key
+ * description:
+ *
+ *	"id:<id>" - request a key by any available ID
+ *
+ * These have to be searched by iteration rather than by direct lookup because
+ * the key is hashed according to its description.
+ */
+static int asymmetric_key_match_preparse(struct key_match_data *match_data)
+{
+	match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
+	return 0;
+}
+
+/*
+ * Free the preparsed the match criterion.
+ */
+static void asymmetric_key_match_free(struct key_match_data *match_data)
+{
+}
+
+/*
  * Describe the asymmetric key
  */
 static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
@@ -196,7 +223,9 @@ struct key_type key_type_asymmetric = {
 	.preparse	= asymmetric_key_preparse,
 	.free_preparse	= asymmetric_key_free_preparse,
 	.instantiate	= generic_key_instantiate,
+	.match_preparse	= asymmetric_key_match_preparse,
 	.match		= asymmetric_key_match,
+	.match_free	= asymmetric_key_match_free,
 	.destroy	= asymmetric_key_destroy,
 	.describe	= asymmetric_key_describe,
 	.def_lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE,