[PATCH v6 3/6] KEYS: make partial key id matching as a dedicated function

From: Mimi Zohar
Date: Tue Jun 24 2014 - 10:42:38 EST


From: Dmitry Kasatkin <d.kasatkin@xxxxxxxxxxx>

To avoid code duplication this patch refactors asymmetric_key_match(),
making partial ID string match a separate function.

This patch also implicitly fixes a bug in the code. asymmetric_key_match()
allows to match the key by its subtype. But subtype matching could be
undone if asymmetric_key_id(key) would return NULL. This patch first
checks for matching spec and then for its value.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@xxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
---
crypto/asymmetric_keys/asymmetric_keys.h | 2 ++
crypto/asymmetric_keys/asymmetric_type.c | 50 ++++++++++++++++++++------------
2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/crypto/asymmetric_keys/asymmetric_keys.h b/crypto/asymmetric_keys/asymmetric_keys.h
index 515b634..a63c551 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.
*/

+int asymmetric_keyid_match(const char *kid, const char *id);
+
static inline const char *asymmetric_key_id(const struct key *key)
{
return key->type_data.p[1];
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index b77eb53..1fd1d30 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -23,6 +23,34 @@ static LIST_HEAD(asymmetric_key_parsers);
static DECLARE_RWSEM(asymmetric_key_parsers_sem);

/*
+ * Match asymmetric key id with partial match
+ * @id: key id to match in a form "id:<id>"
+ */
+int asymmetric_keyid_match(const char *kid, const char *id)
+{
+ size_t idlen, kidlen;
+
+ if (!kid || !id)
+ return 0;
+
+ /* make it possible to use id as in the request: "id:<id>" */
+ if (strncmp(id, "id:", 3) == 0)
+ id += 3;
+
+ /* Anything after here requires a partial match on the ID string */
+ idlen = strlen(id);
+ kidlen = strlen(kid);
+ if (idlen > kidlen)
+ return 0;
+
+ kid += kidlen - idlen;
+ if (strcasecmp(id, kid) != 0)
+ return 0;
+
+ return 1;
+}
+
+/*
* Match asymmetric keys on (part of) their name
* We have some shorthand methods for matching keys. We allow:
*
@@ -34,9 +62,8 @@ static int asymmetric_key_match(const struct key *key, const void *description)
{
const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
const char *spec = description;
- const char *id, *kid;
+ const char *id;
ptrdiff_t speclen;
- size_t idlen, kidlen;

if (!subtype || !spec || !*spec)
return 0;
@@ -55,23 +82,8 @@ static int asymmetric_key_match(const struct key *key, const void *description)
speclen = id - spec;
id++;

- /* Anything after here requires a partial match on the ID string */
- kid = asymmetric_key_id(key);
- if (!kid)
- return 0;
-
- idlen = strlen(id);
- kidlen = strlen(kid);
- if (idlen > kidlen)
- return 0;
-
- kid += kidlen - idlen;
- if (strcasecmp(id, kid) != 0)
- return 0;
-
- if (speclen == 2 &&
- memcmp(spec, "id", 2) == 0)
- return 1;
+ if (speclen == 2 && memcmp(spec, "id", 2) == 0)
+ return asymmetric_keyid_match(asymmetric_key_id(key), id);

if (speclen == subtype->name_len &&
memcmp(spec, subtype->name, speclen) == 0)
--
1.8.1.4

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