linux/security/keys/permission.c
Baolin Wang 074d589895 security: keys: Replace time_t/timespec with time64_t
The 'struct key' will use 'time_t' which we try to remove in the
kernel, since 'time_t' is not year 2038 safe on 32bit systems.
Also the 'struct keyring_search_context' will use 'timespec' type
to record current time, which is also not year 2038 safe on 32bit
systems.

Thus this patch replaces 'time_t' with 'time64_t' which is year 2038
safe for 'struct key', and replace 'timespec' with 'time64_t' for the
'struct keyring_search_context', since we only look at the the seconds
part of 'timespec' variable. Moreover we also change the codes where
using the 'time_t' and 'timespec', and we can get current time by
ktime_get_real_seconds() instead of current_kernel_time(), and use
'TIME64_MAX' macro to initialize the 'time64_t' type variable.

Especially in proc.c file, we have replaced 'unsigned long' and 'timespec'
type with 'u64' and 'time64_t' type to save the timeout value, which means
user will get one 'u64' type timeout value by issuing proc_keys_show()
function.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
2017-11-15 16:38:45 +00:00

111 lines
2.9 KiB
C

/* Key permission checking
*
* 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.
*/
#include <linux/module.h>
#include <linux/security.h>
#include "internal.h"
/**
* key_task_permission - Check a key can be used
* @key_ref: The key to check.
* @cred: The credentials to use.
* @perm: The permissions to check for.
*
* Check to see whether permission is granted to use a key in the desired way,
* but permit the security modules to override.
*
* The caller must hold either a ref on cred or must hold the RCU readlock.
*
* Returns 0 if successful, -EACCES if access is denied based on the
* permissions bits or the LSM check.
*/
int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
unsigned perm)
{
struct key *key;
key_perm_t kperm;
int ret;
key = key_ref_to_ptr(key_ref);
/* use the second 8-bits of permissions for keys the caller owns */
if (uid_eq(key->uid, cred->fsuid)) {
kperm = key->perm >> 16;
goto use_these_perms;
}
/* use the third 8-bits of permissions for keys the caller has a group
* membership in common with */
if (gid_valid(key->gid) && key->perm & KEY_GRP_ALL) {
if (gid_eq(key->gid, cred->fsgid)) {
kperm = key->perm >> 8;
goto use_these_perms;
}
ret = groups_search(cred->group_info, key->gid);
if (ret) {
kperm = key->perm >> 8;
goto use_these_perms;
}
}
/* otherwise use the least-significant 8-bits */
kperm = key->perm;
use_these_perms:
/* use the top 8-bits of permissions for keys the caller possesses
* - possessor permissions are additive with other permissions
*/
if (is_key_possessed(key_ref))
kperm |= key->perm >> 24;
kperm = kperm & perm & KEY_NEED_ALL;
if (kperm != perm)
return -EACCES;
/* let LSM be the final arbiter */
return security_key_permission(key_ref, cred, perm);
}
EXPORT_SYMBOL(key_task_permission);
/**
* key_validate - Validate a key.
* @key: The key to be validated.
*
* Check that a key is valid, returning 0 if the key is okay, -ENOKEY if the
* key is invalidated, -EKEYREVOKED if the key's type has been removed or if
* the key has been revoked or -EKEYEXPIRED if the key has expired.
*/
int key_validate(const struct key *key)
{
unsigned long flags = READ_ONCE(key->flags);
time64_t expiry = READ_ONCE(key->expiry);
if (flags & (1 << KEY_FLAG_INVALIDATED))
return -ENOKEY;
/* check it's still accessible */
if (flags & ((1 << KEY_FLAG_REVOKED) |
(1 << KEY_FLAG_DEAD)))
return -EKEYREVOKED;
/* check it hasn't expired */
if (expiry) {
if (ktime_get_real_seconds() >= expiry)
return -EKEYEXPIRED;
}
return 0;
}
EXPORT_SYMBOL(key_validate);