linux-kernel - [PATCH 7/9] keys: Garbage collect keys for which the domain has been removed [ver #4]

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Date:   Wed, 19 Jun 2019 17:47:43 +0100
From:   David Howells <dhowells@...hat.com>
To:     ebiederm@...ssion.com, keyrings@...r.kernel.org
Cc:     linux-cifs@...r.kernel.org, linux-nfs@...r.kernel.org,
        netdev@...r.kernel.org, linux-afs@...ts.infradead.org,
        dhowells@...hat.com, dwalsh@...hat.com, vgoyal@...hat.com,
        linux-security-module@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 7/9] keys: Garbage collect keys for which the domain has
 been removed [ver #4]

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@...hat.com>
---

 include/linux/key.h      |    2 ++
 security/keys/internal.h |    3 ++-
 security/keys/keyring.c  |   15 +++++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index abc68555bac3..60c076c6e47f 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)
 {
@@ -446,6 +447,7 @@ extern void key_init(void);
 #define key_fsgid_changed(c)		do { } while(0)
 #define key_init()			do { } while(0)
 #define key_free_user_ns(ns)		do { } while(0)
+#define key_remove_domain(d)		do { } while(0)
 
 #endif /* CONFIG_KEYS */
 #endif /* __KERNEL__ */
diff --git a/security/keys/internal.h b/security/keys/internal.h
index d3a9439e2386..5a561f5f199e 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -209,7 +209,8 @@ 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 0da8fa282d56..d3c86fda1510 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -241,6 +241,21 @@ 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.
  *