linux/security/selinux/ss/conditional.h
Jeff Vander Stoep fa1aa143ac selinux: extended permissions for ioctls
Add extended permissions logic to selinux. Extended permissions
provides additional permissions in 256 bit increments. Extend the
generic ioctl permission check to use the extended permissions for
per-command filtering. Source/target/class sets including the ioctl
permission may additionally include a set of commands. Example:

allowxperm <source> <target>:<class> ioctl unpriv_app_socket_cmds
auditallowxperm <source> <target>:<class> ioctl priv_gpu_cmds

Where unpriv_app_socket_cmds and priv_gpu_cmds are macros
representing commonly granted sets of ioctl commands.

When ioctl commands are omitted only the permissions are checked.
This feature is intended to provide finer granularity for the ioctl
permission that may be too imprecise. For example, the same driver
may use ioctls to provide important and benign functionality such as
driver version or socket type as well as dangerous capabilities such
as debugging features, read/write/execute to physical memory or
access to sensitive data. Per-command filtering provides a mechanism
to reduce the attack surface of the kernel, and limit applications
to the subset of commands required.

The format of the policy binary has been modified to include ioctl
commands, and the policy version number has been incremented to
POLICYDB_VERSION_XPERMS_IOCTL=30 to account for the format
change.

The extended permissions logic is deliberately generic to allow
components to be reused e.g. netlink filters

Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Acked-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
2015-07-13 13:31:58 -04:00

83 lines
2.5 KiB
C

/* Authors: Karl MacMillan <kmacmillan@tresys.com>
* Frank Mayer <mayerf@tresys.com>
*
* Copyright (C) 2003 - 2004 Tresys Technology, LLC
* 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, version 2.
*/
#ifndef _CONDITIONAL_H_
#define _CONDITIONAL_H_
#include "avtab.h"
#include "symtab.h"
#include "policydb.h"
#include "../include/conditional.h"
#define COND_EXPR_MAXDEPTH 10
/*
* A conditional expression is a list of operators and operands
* in reverse polish notation.
*/
struct cond_expr {
#define COND_BOOL 1 /* plain bool */
#define COND_NOT 2 /* !bool */
#define COND_OR 3 /* bool || bool */
#define COND_AND 4 /* bool && bool */
#define COND_XOR 5 /* bool ^ bool */
#define COND_EQ 6 /* bool == bool */
#define COND_NEQ 7 /* bool != bool */
#define COND_LAST COND_NEQ
__u32 expr_type;
__u32 bool;
struct cond_expr *next;
};
/*
* Each cond_node contains a list of rules to be enabled/disabled
* depending on the current value of the conditional expression. This
* struct is for that list.
*/
struct cond_av_list {
struct avtab_node *node;
struct cond_av_list *next;
};
/*
* A cond node represents a conditional block in a policy. It
* contains a conditional expression, the current state of the expression,
* two lists of rules to enable/disable depending on the value of the
* expression (the true list corresponds to if and the false list corresponds
* to else)..
*/
struct cond_node {
int cur_state;
struct cond_expr *expr;
struct cond_av_list *true_list;
struct cond_av_list *false_list;
struct cond_node *next;
};
int cond_policydb_init(struct policydb *p);
void cond_policydb_destroy(struct policydb *p);
int cond_init_bool_indexes(struct policydb *p);
int cond_destroy_bool(void *key, void *datum, void *p);
int cond_index_bool(void *key, void *datum, void *datap);
int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp);
int cond_read_list(struct policydb *p, void *fp);
int cond_write_bool(void *key, void *datum, void *ptr);
int cond_write_list(struct policydb *p, struct cond_node *list, void *fp);
void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
struct av_decision *avd, struct extended_perms *xperms);
void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
struct extended_perms_decision *xpermd);
int evaluate_cond_node(struct policydb *p, struct cond_node *node);
#endif /* _CONDITIONAL_H_ */