linux-stable/security/selinux/ss/services.h
Stephen Smalley 1b8b31a2e6 selinux: convert policy read-write lock to RCU
Convert the policy read-write lock to RCU.  This is significantly
simplified by the earlier work to encapsulate the policy data
structures and refactor the policy load and boolean setting logic.
Move the latest_granting sequence number into the selinux_policy
structure so that it can be updated atomically with the policy.
Since removing the policy rwlock and moving latest_granting reduces
the selinux_ss structure to nothing more than a wrapper around the
selinux_policy pointer, get rid of the extra layer of indirection.

At present this change merely passes a hardcoded 1 to
rcu_dereference_check() in the cases where we know we do not need to
take rcu_read_lock(), with the preceding comment explaining why.
Alternatively we could pass fsi->mutex down from selinuxfs and
apply a lockdep check on it instead.

Based in part on earlier attempts to convert the policy rwlock
to RCU by Kaigai Kohei [1] and by Peter Enderborg [2].

[1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/
[2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-25 08:34:47 -04:00

38 lines
998 B
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Implementation of the security services.
*
* Author : Stephen Smalley, <sds@tycho.nsa.gov>
*/
#ifndef _SS_SERVICES_H_
#define _SS_SERVICES_H_
#include "policydb.h"
/* Mapping for a single class */
struct selinux_mapping {
u16 value; /* policy value for class */
unsigned int num_perms; /* number of permissions in class */
u32 perms[sizeof(u32) * 8]; /* policy values for permissions */
};
/* Map for all of the classes, with array size */
struct selinux_map {
struct selinux_mapping *mapping; /* indexed by class */
u16 size; /* array size of mapping */
};
struct selinux_policy {
struct sidtab *sidtab;
struct policydb policydb;
struct selinux_map map;
u32 latest_granting;
} __randomize_layout;
void services_compute_xperms_drivers(struct extended_perms *xperms,
struct avtab_node *node);
void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
struct avtab_node *node);
#endif /* _SS_SERVICES_H_ */