From: David Howells <dhowells@redhat.com>
To: keyrings@vger.kernel.org
Cc: dhowells@redhat.com, linux-afs@lists.infradead.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 5/6] afs: Provide an RCU-capable key lookup
Date: Wed, 22 May 2019 22:46:38 +0000 [thread overview]
Message-ID: <155856519817.11737.3095092075887198321.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <155856516286.11737.11196637682919902718.stgit@warthog.procyon.org.uk>
Provide an RCU-capable key lookup function. We don't want to call
afs_request_key() in RCU-mode pathwalk as request_key() might sleep, even if
we don't ask it to construct anything as it might find a key that is currently
undergoing construction.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/afs/internal.h | 1 +
fs/afs/security.c | 27 +++++++++++++++++++++++++++
2 files changed, 28 insertions(+)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 2073c1a3ab4b..3090efcc823f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1237,6 +1237,7 @@ extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int,
struct afs_status_cb *);
extern void afs_zap_permits(struct rcu_head *);
extern struct key *afs_request_key(struct afs_cell *);
+extern struct key *afs_request_key_rcu(struct afs_cell *);
extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);
extern int afs_permission(struct inode *, int);
extern void __exit afs_clean_up_permit_cache(void);
diff --git a/fs/afs/security.c b/fs/afs/security.c
index 5d8ece98561e..a6582d6a3882 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -49,6 +49,33 @@ struct key *afs_request_key(struct afs_cell *cell)
}
}
+/*
+ * Get a key when pathwalk is in rcuwalk mode.
+ */
+struct key *afs_request_key_rcu(struct afs_cell *cell)
+{
+ struct key *key;
+
+ _enter("{%x}", key_serial(cell->anonymous_key));
+
+ _debug("key %s", cell->anonymous_key->description);
+ key = request_key_rcu(&key_type_rxrpc, cell->anonymous_key->description);
+ if (IS_ERR(key)) {
+ if (PTR_ERR(key) != -ENOKEY) {
+ _leave(" = %ld", PTR_ERR(key));
+ return key;
+ }
+
+ /* act as anonymous user */
+ _leave(" = {%x} [anon]", key_serial(cell->anonymous_key));
+ return cell->anonymous_key;
+ } else {
+ /* act as authorised user */
+ _leave(" = {%x} [auth]", key_serial(key));
+ return key;
+ }
+}
+
/*
* Dispose of a list of permits.
*/
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: keyrings@vger.kernel.org
Cc: dhowells@redhat.com, linux-afs@lists.infradead.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 5/6] afs: Provide an RCU-capable key lookup
Date: Wed, 22 May 2019 23:46:38 +0100 [thread overview]
Message-ID: <155856519817.11737.3095092075887198321.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <155856516286.11737.11196637682919902718.stgit@warthog.procyon.org.uk>
Provide an RCU-capable key lookup function. We don't want to call
afs_request_key() in RCU-mode pathwalk as request_key() might sleep, even if
we don't ask it to construct anything as it might find a key that is currently
undergoing construction.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/afs/internal.h | 1 +
fs/afs/security.c | 27 +++++++++++++++++++++++++++
2 files changed, 28 insertions(+)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 2073c1a3ab4b..3090efcc823f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1237,6 +1237,7 @@ extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int,
struct afs_status_cb *);
extern void afs_zap_permits(struct rcu_head *);
extern struct key *afs_request_key(struct afs_cell *);
+extern struct key *afs_request_key_rcu(struct afs_cell *);
extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);
extern int afs_permission(struct inode *, int);
extern void __exit afs_clean_up_permit_cache(void);
diff --git a/fs/afs/security.c b/fs/afs/security.c
index 5d8ece98561e..a6582d6a3882 100644
--- a/fs/afs/security.c
+++ b/fs/afs/security.c
@@ -49,6 +49,33 @@ struct key *afs_request_key(struct afs_cell *cell)
}
}
+/*
+ * Get a key when pathwalk is in rcuwalk mode.
+ */
+struct key *afs_request_key_rcu(struct afs_cell *cell)
+{
+ struct key *key;
+
+ _enter("{%x}", key_serial(cell->anonymous_key));
+
+ _debug("key %s", cell->anonymous_key->description);
+ key = request_key_rcu(&key_type_rxrpc, cell->anonymous_key->description);
+ if (IS_ERR(key)) {
+ if (PTR_ERR(key) != -ENOKEY) {
+ _leave(" = %ld", PTR_ERR(key));
+ return key;
+ }
+
+ /* act as anonymous user */
+ _leave(" = {%x} [anon]", key_serial(cell->anonymous_key));
+ return cell->anonymous_key;
+ } else {
+ /* act as authorised user */
+ _leave(" = {%x} [auth]", key_serial(key));
+ return key;
+ }
+}
+
/*
* Dispose of a list of permits.
*/
next prev parent reply other threads:[~2019-05-22 22:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 22:46 [PATCH 0/6] keys: request_key() improvements(vspace)s David Howells
2019-05-22 22:46 ` David Howells
2019-05-22 22:46 ` [PATCH 1/6] keys: Fix request_key() lack of Link perm check on found key David Howells
2019-05-22 22:46 ` David Howells
2019-05-22 22:46 ` [PATCH 2/6] keys: Invalidate used request_key authentication keys David Howells
2019-05-22 22:46 ` David Howells
2019-05-22 22:46 ` [PATCH 3/6] keys: Move the RCU locks outwards from the keyring search functions David Howells
2019-05-22 22:46 ` David Howells
2019-05-22 22:46 ` [PATCH 4/6] keys: Cache result of request_key*() temporarily in task_struct David Howells
2019-05-22 22:46 ` David Howells
2019-05-22 22:46 ` David Howells [this message]
2019-05-22 22:46 ` [PATCH 5/6] afs: Provide an RCU-capable key lookup David Howells
2019-05-22 22:46 ` [PATCH 6/6] afs: Support RCU pathwalk David Howells
2019-05-22 22:46 ` David Howells
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