[RFC PATCH 6/9] keys: Garbage collect keys for which the domain has been removed

[David Howells <dhowells@redhat.com>]

If a key operation domain (such as a network namespace) has been removed
then attempt to garbage collect all the keys that use it.

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

 include/linux/key.h      |    1 +
 security/keys/internal.h |    3 ++-
 security/keys/keyring.c  |   15 +++++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index bb716c33bffe..324753fc3efc 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -278,6 +278,7 @@ extern void key_revoke(struct key *key);
 extern void key_invalidate(struct key *key);
 extern void key_put(struct key *key);
 extern bool key_put_tag(struct key_tag *tag);
+extern void key_remove_domain(struct key_tag *domain_tag);
 
 static inline struct key *__key_get(struct key *key)
 {
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 3154ba59a2f0..7968c8ebb043 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -203,7 +203,8 @@ static inline bool key_is_dead(const struct key *key, time64_t limit)
 	return
 		key->flags & ((1 << KEY_FLAG_DEAD) |
 			      (1 << KEY_FLAG_INVALIDATED)) ||
-		(key->expiry > 0 && key->expiry <= limit);
+		(key->expiry > 0 && key->expiry <= limit) ||
+		key->domain_tag->removed;
 }
 
 /*
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 0df10221c037..916a52d54e1b 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -247,6 +247,21 @@ bool key_put_tag(struct key_tag *tag)
 	return false;
 }
 
+/**
+ * key_remove_domain - Kill off a key domain and gc its keys
+ * @domain_tag: The domain tag to release.
+ *
+ * This marks a domain tag as being dead and releases a ref on it.  If that
+ * wasn't the last reference, the garbage collector is poked to try and delete
+ * all keys that were in the domain.
+ */
+void key_remove_domain(struct key_tag *domain_tag)
+{
+	domain_tag->removed = true;
+	if (!key_put_tag(domain_tag))
+		key_schedule_gc_links();
+}
+
 /*
  * Build the next index key chunk.
  *