linux/security/apparmor/mount.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppArmor security module
 *
 * This file contains AppArmor mediation of files
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2017 Canonical Ltd.
 */

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <uapi/linux/mount.h>

#include "include/apparmor.h"
#include "include/audit.h"
#include "include/cred.h"
#include "include/domain.h"
#include "include/file.h"
#include "include/match.h"
#include "include/mount.h"
#include "include/path.h"
#include "include/policy.h"


static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags)
{ … }

/**
 * audit_cb - call back for mount specific audit fields
 * @ab: audit_buffer  (NOT NULL)
 * @va: audit struct to audit values of  (NOT NULL)
 */
static void audit_cb(struct audit_buffer *ab, void *va)
{ … }

/**
 * audit_mount - handle the auditing of mount operations
 * @subj_cred: cred of the subject
 * @profile: the profile being enforced  (NOT NULL)
 * @op: operation being mediated (NOT NULL)
 * @name: name of object being mediated (MAYBE NULL)
 * @src_name: src_name of object being mediated (MAYBE_NULL)
 * @type: type of filesystem (MAYBE_NULL)
 * @trans: name of trans (MAYBE NULL)
 * @flags: filesystem independent mount flags
 * @data: filesystem mount flags
 * @request: permissions requested
 * @perms: the permissions computed for the request (NOT NULL)
 * @info: extra information message (MAYBE NULL)
 * @error: 0 if operation allowed else failure error code
 *
 * Returns: %0 or error on failure
 */
static int audit_mount(const struct cred *subj_cred,
		       struct aa_profile *profile, const char *op,
		       const char *name, const char *src_name,
		       const char *type, const char *trans,
		       unsigned long flags, const void *data, u32 request,
		       struct aa_perms *perms, const char *info, int error)
{ … }

/**
 * match_mnt_flags - Do an ordered match on mount flags
 * @dfa: dfa to match against
 * @state: state to start in
 * @flags: mount flags to match against
 *
 * Mount flags are encoded as an ordered match. This is done instead of
 * checking against a simple bitmask, to allow for logical operations
 * on the flags.
 *
 * Returns: next state after flags match
 */
static aa_state_t match_mnt_flags(struct aa_dfa *dfa, aa_state_t state,
				    unsigned long flags)
{ … }

static const char * const mnt_info_table[] = …;

/*
 * Returns 0 on success else element that match failed in, this is the
 * index into the mnt_info_table above
 */
static int do_match_mnt(struct aa_policydb *policy, aa_state_t start,
			const char *mntpnt, const char *devname,
			const char *type, unsigned long flags,
			void *data, bool binary, struct aa_perms *perms)
{ … }


static int path_flags(struct aa_profile *profile, const struct path *path)
{ … }

/**
 * match_mnt_path_str - handle path matching for mount
 * @subj_cred: cred of confined subject
 * @profile: the confining profile
 * @mntpath: for the mntpnt (NOT NULL)
 * @buffer: buffer to be used to lookup mntpath
 * @devname: string for the devname/src_name (MAY BE NULL OR ERRPTR)
 * @type: string for the dev type (MAYBE NULL)
 * @flags: mount flags to match
 * @data: fs mount data (MAYBE NULL)
 * @binary: whether @data is binary
 * @devinfo: error str if (IS_ERR(@devname))
 *
 * Returns: 0 on success else error
 */
static int match_mnt_path_str(const struct cred *subj_cred,
			      struct aa_profile *profile,
			      const struct path *mntpath, char *buffer,
			      const char *devname, const char *type,
			      unsigned long flags, void *data, bool binary,
			      const char *devinfo)
{ … }

/**
 * match_mnt - handle path matching for mount
 * @subj_cred: cred of the subject
 * @profile: the confining profile
 * @path: for the mntpnt (NOT NULL)
 * @buffer: buffer to be used to lookup mntpath
 * @devpath: path devname/src_name (MAYBE NULL)
 * @devbuffer: buffer to be used to lookup devname/src_name
 * @type: string for the dev type (MAYBE NULL)
 * @flags: mount flags to match
 * @data: fs mount data (MAYBE NULL)
 * @binary: whether @data is binary
 *
 * Returns: 0 on success else error
 */
static int match_mnt(const struct cred *subj_cred,
		     struct aa_profile *profile, const struct path *path,
		     char *buffer, const struct path *devpath, char *devbuffer,
		     const char *type, unsigned long flags, void *data,
		     bool binary)
{ … }

int aa_remount(const struct cred *subj_cred,
	       struct aa_label *label, const struct path *path,
	       unsigned long flags, void *data)
{ … }

int aa_bind_mount(const struct cred *subj_cred,
		  struct aa_label *label, const struct path *path,
		  const char *dev_name, unsigned long flags)
{ … }

int aa_mount_change_type(const struct cred *subj_cred,
			 struct aa_label *label, const struct path *path,
			 unsigned long flags)
{ … }

int aa_move_mount(const struct cred *subj_cred,
		  struct aa_label *label, const struct path *from_path,
		  const struct path *to_path)
{ … }

int aa_move_mount_old(const struct cred *subj_cred, struct aa_label *label,
		      const struct path *path, const char *orig_name)
{ … }

int aa_new_mount(const struct cred *subj_cred, struct aa_label *label,
		 const char *dev_name, const struct path *path,
		 const char *type, unsigned long flags, void *data)
{ … }

static int profile_umount(const struct cred *subj_cred,
			  struct aa_profile *profile, const struct path *path,
			  char *buffer)
{ … }

int aa_umount(const struct cred *subj_cred, struct aa_label *label,
	      struct vfsmount *mnt, int flags)
{ … }

/* helper fn for transition on pivotroot
 *
 * Returns: label for transition or ERR_PTR. Does not return NULL
 */
static struct aa_label *build_pivotroot(const struct cred *subj_cred,
					struct aa_profile *profile,
					const struct path *new_path,
					char *new_buffer,
					const struct path *old_path,
					char *old_buffer)
{ … }

int aa_pivotroot(const struct cred *subj_cred, struct aa_label *label,
		 const struct path *old_path,
		 const struct path *new_path)
{ … }