linux/include/keys/user-type.h
Eric Biggers cc1780fc42 KEYS: user: Align the payload buffer
Align the payload of "user" and "logon" keys so that users of the
keyrings service can access it as a struct that requires more than
2-byte alignment.  fscrypt currently does this which results in the read
of fscrypt_key::size being misaligned as it needs 4-byte alignment.

Align to __alignof__(u64) rather than __alignof__(long) since in the
future it's conceivable that people would use structs beginning with
u64, which on some platforms would require more than 'long' alignment.

Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Fixes: 2aa349f6e3 ("[PATCH] Keys: Export user-defined keyring operations")
Fixes: 88bd6ccdcd ("ext4 crypto: add encryption key management facilities")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
2019-02-22 10:11:19 -08:00

64 lines
2.1 KiB
C

/* user-type.h: User-defined key type
*
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _KEYS_USER_TYPE_H
#define _KEYS_USER_TYPE_H
#include <linux/key.h>
#include <linux/rcupdate.h>
#ifdef CONFIG_KEYS
/*****************************************************************************/
/*
* the payload for a key of type "user" or "logon"
* - once filled in and attached to a key:
* - the payload struct is invariant may not be changed, only replaced
* - the payload must be read with RCU procedures or with the key semaphore
* held
* - the payload may only be replaced with the key semaphore write-locked
* - the key's data length is the size of the actual data, not including the
* payload wrapper
*/
struct user_key_payload {
struct rcu_head rcu; /* RCU destructor */
unsigned short datalen; /* length of this data */
char data[0] __aligned(__alignof__(u64)); /* actual data */
};
extern struct key_type key_type_user;
extern struct key_type key_type_logon;
struct key_preparsed_payload;
extern int user_preparse(struct key_preparsed_payload *prep);
extern void user_free_preparse(struct key_preparsed_payload *prep);
extern int user_update(struct key *key, struct key_preparsed_payload *prep);
extern void user_revoke(struct key *key);
extern void user_destroy(struct key *key);
extern void user_describe(const struct key *user, struct seq_file *m);
extern long user_read(const struct key *key,
char __user *buffer, size_t buflen);
static inline const struct user_key_payload *user_key_payload_rcu(const struct key *key)
{
return (struct user_key_payload *)dereference_key_rcu(key);
}
static inline struct user_key_payload *user_key_payload_locked(const struct key *key)
{
return (struct user_key_payload *)dereference_key_locked((struct key *)key);
}
#endif /* CONFIG_KEYS */
#endif /* _KEYS_USER_TYPE_H */