[mirror_ubuntu-zesty-kernel.git] / security / apparmor / mount.c

/*
 * AppArmor security module
 *
 * This file contains AppArmor mediation of files
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2012 Canonical Ltd.
 *
 * 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 of the
 * License.
 */

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

#include "include/apparmor.h"
#include "include/audit.h"
#include "include/context.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)
{
	if (flags & MS_RDONLY)
		audit_log_format(ab, "ro");
	else
		audit_log_format(ab, "rw");
	if (flags & MS_NOSUID)
		audit_log_format(ab, ", nosuid");
	if (flags & MS_NODEV)
		audit_log_format(ab, ", nodev");
	if (flags & MS_NOEXEC)
		audit_log_format(ab, ", noexec");
	if (flags & MS_SYNCHRONOUS)
		audit_log_format(ab, ", sync");
	if (flags & MS_REMOUNT)
		audit_log_format(ab, ", remount");
	if (flags & MS_MANDLOCK)
		audit_log_format(ab, ", mand");
	if (flags & MS_DIRSYNC)
		audit_log_format(ab, ", dirsync");
	if (flags & MS_NOATIME)
		audit_log_format(ab, ", noatime");
	if (flags & MS_NODIRATIME)
		audit_log_format(ab, ", nodiratime");
	if (flags & MS_BIND)
		audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind");
	if (flags & MS_MOVE)
		audit_log_format(ab, ", move");
	if (flags & MS_SILENT)
		audit_log_format(ab, ", silent");
	if (flags & MS_POSIXACL)
		audit_log_format(ab, ", acl");
	if (flags & MS_UNBINDABLE)
		audit_log_format(ab, flags & MS_REC ? ", runbindable" :
				 ", unbindable");
	if (flags & MS_PRIVATE)
		audit_log_format(ab, flags & MS_REC ? ", rprivate" :
				 ", private");
	if (flags & MS_SLAVE)
		audit_log_format(ab, flags & MS_REC ? ", rslave" :
				 ", slave");
	if (flags & MS_SHARED)
		audit_log_format(ab, flags & MS_REC ? ", rshared" :
				 ", shared");
	if (flags & MS_RELATIME)
		audit_log_format(ab, ", relatime");
	if (flags & MS_I_VERSION)
		audit_log_format(ab, ", iversion");
	if (flags & MS_STRICTATIME)
		audit_log_format(ab, ", strictatime");
	if (flags & MS_NOUSER)
		audit_log_format(ab, ", nouser");
}

/**
 * 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)
{
	struct common_audit_data *sa = va;

	if (aad(sa)->mnt.type) {
		audit_log_format(ab, " fstype=");
		audit_log_untrustedstring(ab, aad(sa)->mnt.type);
	}
	if (aad(sa)->mnt.src_name) {
		audit_log_format(ab, " srcname=");
		audit_log_untrustedstring(ab, aad(sa)->mnt.src_name);
	}
	if (aad(sa)->mnt.trans) {
		audit_log_format(ab, " trans=");
		audit_log_untrustedstring(ab, aad(sa)->mnt.trans);
	}
	if (aad(sa)->mnt.flags) {
		audit_log_format(ab, " flags=\"");
		audit_mnt_flags(ab, aad(sa)->mnt.flags);
		audit_log_format(ab, "\"");
	}
	if (aad(sa)->mnt.data) {
		audit_log_format(ab, " options=");
		audit_log_untrustedstring(ab, aad(sa)->mnt.data);
	}
}

/**
 * audit_mount - handle the auditing of mount operations
 * @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 idependent 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(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)
{
	int audit_type = AUDIT_APPARMOR_AUTO;
	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);

	if (likely(!error)) {
		u32 mask = perms->audit;

		if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
			mask = 0xffff;

		/* mask off perms that are not being force audited */
		request &= mask;

		if (likely(!request))
			return 0;
		audit_type = AUDIT_APPARMOR_AUDIT;
	} else {
		/* only report permissions that were denied */
		request = request & ~perms->allow;

		if (request & perms->kill)
			audit_type = AUDIT_APPARMOR_KILL;

		/* quiet known rejects, assumes quiet and kill do not overlap */
		if ((request & perms->quiet) &&
		    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
		    AUDIT_MODE(profile) != AUDIT_ALL)
			request &= ~perms->quiet;

		if (!request)
			return error;
	}

	aad(&sa)->name = name;
	aad(&sa)->mnt.src_name = src_name;
	aad(&sa)->mnt.type = type;
	aad(&sa)->mnt.trans = trans;
	aad(&sa)->mnt.flags = flags;
	if (data && (perms->audit & AA_AUDIT_DATA))
		aad(&sa)->mnt.data = data;
	aad(&sa)->info = info;
	aad(&sa)->error = error;

	return aa_audit(audit_type, profile, &sa, audit_cb);
}

/**
 * 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 unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state,
				    unsigned long flags)
{
	unsigned int i;

	for (i = 0; i <= 31 ; ++i) {
		if ((1 << i) & flags)
			state = aa_dfa_next(dfa, state, i + 1);
	}

	return state;
}

/**
 * compute_mnt_perms - compute mount permission associated with @state
 * @dfa: dfa to match against (NOT NULL)
 * @state: state match finished in
 *
 * Returns: mount permissions
 */
static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa,
					   unsigned int state)
{
	struct aa_perms perms;

	perms.kill = 0;
	perms.allow = dfa_user_allow(dfa, state);
	perms.audit = dfa_user_audit(dfa, state);
	perms.quiet = dfa_user_quiet(dfa, state);
	perms.xindex = dfa_user_xindex(dfa, state);

	return perms;
}

static const char *mnt_info_table[] = {
	"match succeeded",
	"failed mntpnt match",
	"failed srcname match",
	"failed type match",
	"failed flags match",
	"failed data match"
};

/*
 * 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_dfa *dfa, unsigned int start,
			const char *mntpnt, const char *devname,
			const char *type, unsigned long flags,
			void *data, bool binary, struct aa_perms *perms)
{
	unsigned int state;

	AA_BUG(!dfa);
	AA_BUG(!perms);

	state = aa_dfa_match(dfa, start, mntpnt);
	state = aa_dfa_null_transition(dfa, state);
	if (!state)
		return 1;

	if (devname)
		state = aa_dfa_match(dfa, state, devname);
	state = aa_dfa_null_transition(dfa, state);
	if (!state)
		return 2;

	if (type)
		state = aa_dfa_match(dfa, state, type);
	state = aa_dfa_null_transition(dfa, state);
	if (!state)
		return 3;

	state = match_mnt_flags(dfa, state, flags);
	if (!state)
		return 4;
	*perms = compute_mnt_perms(dfa, state);
	if (perms->allow & AA_MAY_MOUNT)
		return 0;

	/* only match data if not binary and the DFA flags data is expected */
	if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
		state = aa_dfa_null_transition(dfa, state);
		if (!state)
			return 4;

		state = aa_dfa_match(dfa, state, data);
		if (!state)
			return 5;
		*perms = compute_mnt_perms(dfa, state);
		if (perms->allow & AA_MAY_MOUNT)
			return 0;
	}

	/* failed at end of flags match */
	return 4;
}


static int path_flags(struct aa_profile *profile, const struct path *path)
{
	AA_BUG(!profile);
	AA_BUG(!path);

	return profile->path_flags |
		(S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0);
}

/**
 * match_mnt_path_str - handle path matching for mount
 * @profile: the confining profile
 * @mntpath: for the mntpnt (NOT NULL)
 * @buffer: buffer to be used to lookup mntpath
 * @devnme: 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(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)
{
	struct aa_perms perms = { };
	const char *mntpnt = NULL, *info = NULL;
	int pos, error;

	AA_BUG(!profile);
	AA_BUG(!mntpath);
	AA_BUG(!buffer);

	error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
			     &mntpnt, &info, profile->disconnected);
	if (error)
		goto audit;
	if (IS_ERR(devname)) {
		error = PTR_ERR(devname);
		info = devinfo;
		goto audit;
	}

	error = -EACCES;
	pos = do_match_mnt(profile->policy.dfa,
			   profile->policy.start[AA_CLASS_MOUNT],
			   mntpnt, devname, type, flags, data, binary, &perms);
	if (pos) {
		info = mnt_info_table[pos];
		goto audit;
	}
	error = 0;

audit:
	return audit_mount(profile, OP_MOUNT, mntpnt, devname, type, NULL,
			   flags, data, AA_MAY_MOUNT, &perms, info, error);
}

/**
 * match_mnt - handle path matching for mount
 * @profile: the confining profile
 * @mntpath: 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(struct aa_profile *profile, const struct path *path,
		     char *buffer, struct path *devpath, char *devbuffer,
		     const char *type, unsigned long flags, void *data,
		     bool binary)
{
	const char *devname = NULL, *info = NULL;
	int error = -EACCES;

	AA_BUG(!profile);
	AA_BUG(devpath && !devbuffer);

	if (devpath) {
		error = aa_path_name(devpath, path_flags(profile, devpath),
				     devbuffer, &devname, &info,
				     profile->disconnected);
		if (error)
			devname = ERR_PTR(error);
	}

	return match_mnt_path_str(profile, path, buffer, devname, type, flags,
				  data, binary, info);
}

int aa_remount(struct aa_label *label, const struct path *path,
	       unsigned long flags, void *data)
{
	struct aa_profile *profile;
	char *buffer = NULL;
	bool binary;
	int error;

	AA_BUG(!label);
	AA_BUG(!path);

	binary = path->dentry->d_sb->s_type->fs_flags & FS_BINARY_MOUNTDATA;

	get_buffers(buffer);
	error = fn_for_each_confined(label, profile,
			match_mnt(profile, path, buffer, NULL, NULL, NULL,
				  flags, data, binary));
	put_buffers(buffer);

	return error;
}

int aa_bind_mount(struct aa_label *label, const struct path *path,
		  const char *dev_name, unsigned long flags)
{
	struct aa_profile *profile;
	char *buffer = NULL, *old_buffer = NULL;
	struct path old_path;
	int error;

	AA_BUG(!label);
	AA_BUG(!path);

	if (!dev_name || !*dev_name)
		return -EINVAL;

	flags &= MS_REC | MS_BIND;

	error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
	if (error)
		return error;

	get_buffers(buffer, old_buffer);
	error = fn_for_each_confined(label, profile,
			match_mnt(profile, path, buffer, &old_path, old_buffer,
				  NULL, flags, NULL, false));
	put_buffers(buffer, old_buffer);
	path_put(&old_path);

	return error;
}

int aa_mount_change_type(struct aa_label *label, const struct path *path,
			 unsigned long flags)
{
	struct aa_profile *profile;
	char *buffer = NULL;
	int error;

	AA_BUG(!label);
	AA_BUG(!path);

	/* These are the flags allowed by do_change_type() */
	flags &= (MS_REC | MS_SILENT | MS_SHARED | MS_PRIVATE | MS_SLAVE |
		  MS_UNBINDABLE);

	get_buffers(buffer);
	error = fn_for_each_confined(label, profile,
			match_mnt(profile, path, buffer, NULL, NULL, NULL,
				  flags, NULL, false));
	put_buffers(buffer);

	return error;
}

int aa_move_mount(struct aa_label *label, const struct path *path,
		  const char *orig_name)
{
	struct aa_profile *profile;
	char *buffer = NULL, *old_buffer = NULL;
	struct path old_path;
	int error;

	AA_BUG(!label);
	AA_BUG(!path);

	if (!orig_name || !*orig_name)
		return -EINVAL;

	error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);
	if (error)
		return error;

	get_buffers(buffer, old_buffer);
	error = fn_for_each_confined(label, profile,
			match_mnt(profile, path, buffer, &old_path, old_buffer,
				  NULL, MS_MOVE, NULL, false));
	put_buffers(buffer, old_buffer);
	path_put(&old_path);

	return error;
}

int aa_new_mount(struct aa_label *label, const char *dev_name,
		 const struct path *path, const char *type, unsigned long flags,
		 void *data)
{
	struct aa_profile *profile;
	char *buffer = NULL, *dev_buffer = NULL;
	bool binary = true;
	int error;
	int requires_dev = 0;
	struct path tmp_path, *dev_path = NULL;

	AA_BUG(!label);
	AA_BUG(!path);

	if (type) {
		struct file_system_type *fstype;
		fstype = get_fs_type(type);
		if (!fstype)
			return -ENODEV;
		binary = fstype->fs_flags & FS_BINARY_MOUNTDATA;
		requires_dev = fstype->fs_flags & FS_REQUIRES_DEV;
		put_filesystem(fstype);

		if (requires_dev) {
			if (!dev_name || !*dev_name)
				return -ENOENT;

			error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path);
			if (error)
				return error;
			dev_path = &tmp_path;
		}
	}

	get_buffers(buffer, dev_buffer);
	if (dev_path) {
		error = fn_for_each_confined(label, profile,
			match_mnt(profile, path, buffer, dev_path, dev_buffer,
				  type, flags, data, binary));
	} else {
		error = fn_for_each_confined(label, profile,
			match_mnt_path_str(profile, path, buffer, dev_name,
					   type, flags, data, binary, NULL));
	}
	put_buffers(buffer, dev_buffer);
	if (dev_path)
		path_put(dev_path);

	return error;
}

static int profile_umount(struct aa_profile *profile, struct path *path,
			  char *buffer)
{
	struct aa_perms perms = { };
	const char *name = NULL, *info = NULL;
	unsigned int state;
	int error;

	AA_BUG(!profile);
	AA_BUG(!path);

	error = aa_path_name(path, path_flags(profile, path), buffer, &name,
			     &info, profile->disconnected);
	if (error)
		goto audit;

	state = aa_dfa_match(profile->policy.dfa,
			     profile->policy.start[AA_CLASS_MOUNT],
			     name);
	perms = compute_mnt_perms(profile->policy.dfa, state);
	if (AA_MAY_UMOUNT & ~perms.allow)
		error = -EACCES;

audit:
	return audit_mount(profile, OP_UMOUNT, name, NULL, NULL, NULL, 0, NULL,
			   AA_MAY_UMOUNT, &perms, info, error);
}

int aa_umount(struct aa_label *label, struct vfsmount *mnt, int flags)
{
	struct aa_profile *profile;
	char *buffer = NULL;
	int error;
	struct path path = { mnt, mnt->mnt_root };

	AA_BUG(!label);
	AA_BUG(!mnt);

	get_buffers(buffer);
	error = fn_for_each_confined(label, profile,
			profile_umount(profile, &path, buffer));
	put_buffers(buffer);

	return error;
}

/* helper fn for transition on pivotroot
 *
 * Returns: label for transition or ERR_PTR. Does not return NULL
 */
static struct aa_label *build_pivotroot(struct aa_profile *profile,
					struct path *new_path,
					char *new_buffer,
					struct path *old_path,
					char *old_buffer)
{
	const char *old_name, *new_name = NULL, *info = NULL;
	const char *trans_name = NULL;
	struct aa_label *target = NULL;
	struct aa_perms perms = { };
	unsigned int state;
	int error;

	AA_BUG(!profile);
	AA_BUG(!new_path);
	AA_BUG(!old_path);

	error = aa_path_name(old_path, path_flags(profile, old_path),
			     old_buffer, &old_name, &info,
			     profile->disconnected);
	if (error)
		goto audit;
	error = aa_path_name(new_path, path_flags(profile, new_path),
			     new_buffer, &new_name, &info,
			     profile->disconnected);
	if (error)
		goto audit;

	error = -EACCES;
	state = aa_dfa_match(profile->policy.dfa,
			     profile->policy.start[AA_CLASS_MOUNT],
			     new_name);
	state = aa_dfa_null_transition(profile->policy.dfa, state);
	state = aa_dfa_match(profile->policy.dfa, state, old_name);
	perms = compute_mnt_perms(profile->policy.dfa, state);

	if (AA_MAY_PIVOTROOT & perms.allow) {
		error = 0;
		if ((perms.xindex & AA_X_TYPE_MASK) == AA_X_TABLE) {
			target = x_table_lookup(profile, perms.xindex,
						&trans_name);
			if (!target)
				error = -ENOENT;
		}
	}

audit:
	error = audit_mount(profile, OP_PIVOTROOT, new_name, old_name,
			    NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT,
			    &perms, info, error);
	if (error) {
		aa_put_label(target);
		return ERR_PTR(error);
	} else if (target)
		return target;

	return aa_get_label(&profile->label);
}

int aa_pivotroot(struct aa_label *label, const struct path *old_path,
		 const struct path *new_path)
{
	struct aa_profile *profile;
	struct aa_label *target = NULL;
	char *old_buffer = NULL, *new_buffer = NULL, *info = NULL;
	int error;

	AA_BUG(!label);
	AA_BUG(!old_path);
	AA_BUG(!new_path);

	get_buffers(old_buffer, new_buffer);
	target = fn_label_build(label, profile, GFP_ATOMIC,
			build_pivotroot(profile, new_path, new_buffer,
					old_path, old_buffer));
	if (!target) {
		info = "label build failed";
		error = -ENOMEM;
		goto fail;
	} else if (!IS_ERR(target)) {
		error = aa_replace_current_label(target);
		if (error) {
			/* TODO: audit target */
			aa_put_label(target);
			goto out;
		}
	} else
		/* already audited error */
		error = PTR_ERR(target);
out:
	put_buffers(old_buffer, new_buffer);

	return error;

fail:
	/* TODO: add back in auditing of new_name and old_name */
	error = fn_for_each(label, profile,
			audit_mount(profile, OP_PIVOTROOT, NULL /*new_name */,
				    NULL /* old_name */,
				    NULL, NULL,
				    0, NULL, AA_MAY_PIVOTROOT, &nullperms, info,
				    error));
	goto out;
}
Commit	Line	Data
80594fc2 JJ	1	/*
	2	* AppArmor security module
	3	*
	4	* This file contains AppArmor mediation of files
	5	*
	6	* Copyright (C) 1998-2008 Novell/SUSE
	7	* Copyright 2009-2012 Canonical Ltd.
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License as
	11	* published by the Free Software Foundation, version 2 of the
	12	* License.
	13	*/
	14
	15	#include <linux/fs.h>
	16	#include <linux/mount.h>
	17	#include <linux/namei.h>
	18
	19	#include "include/apparmor.h"
	20	#include "include/audit.h"
	21	#include "include/context.h"
	22	#include "include/domain.h"
	23	#include "include/file.h"
	24	#include "include/match.h"
	25	#include "include/mount.h"
	26	#include "include/path.h"
	27	#include "include/policy.h"
	28
	29
	30	static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags)
	31	{
	32	if (flags & MS_RDONLY)
	33	audit_log_format(ab, "ro");
	34	else
	35	audit_log_format(ab, "rw");
	36	if (flags & MS_NOSUID)
	37	audit_log_format(ab, ", nosuid");
	38	if (flags & MS_NODEV)
	39	audit_log_format(ab, ", nodev");
	40	if (flags & MS_NOEXEC)
	41	audit_log_format(ab, ", noexec");
	42	if (flags & MS_SYNCHRONOUS)
	43	audit_log_format(ab, ", sync");
	44	if (flags & MS_REMOUNT)
	45	audit_log_format(ab, ", remount");
	46	if (flags & MS_MANDLOCK)
	47	audit_log_format(ab, ", mand");
	48	if (flags & MS_DIRSYNC)
	49	audit_log_format(ab, ", dirsync");
	50	if (flags & MS_NOATIME)
	51	audit_log_format(ab, ", noatime");
	52	if (flags & MS_NODIRATIME)
	53	audit_log_format(ab, ", nodiratime");
	54	if (flags & MS_BIND)
	55	audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind");
	56	if (flags & MS_MOVE)
	57	audit_log_format(ab, ", move");
	58	if (flags & MS_SILENT)
	59	audit_log_format(ab, ", silent");
	60	if (flags & MS_POSIXACL)
	61	audit_log_format(ab, ", acl");
	62	if (flags & MS_UNBINDABLE)
	63	audit_log_format(ab, flags & MS_REC ? ", runbindable" :
	64	", unbindable");
65	if (flags & MS_PRIVATE)
66	audit_log_format(ab, flags & MS_REC ? ", rprivate" :
67	", private");
68	if (flags & MS_SLAVE)
69	audit_log_format(ab, flags & MS_REC ? ", rslave" :
70	", slave");
71	if (flags & MS_SHARED)
72	audit_log_format(ab, flags & MS_REC ? ", rshared" :
73	", shared");
74	if (flags & MS_RELATIME)
75	audit_log_format(ab, ", relatime");
76	if (flags & MS_I_VERSION)
77	audit_log_format(ab, ", iversion");
78	if (flags & MS_STRICTATIME)
79	audit_log_format(ab, ", strictatime");
80	if (flags & MS_NOUSER)
81	audit_log_format(ab, ", nouser");
82	}
83
84	/**
85	* audit_cb - call back for mount specific audit fields
86	* @ab: audit_buffer (NOT NULL)
87	* @va: audit struct to audit values of (NOT NULL)
88	*/
89	static void audit_cb(struct audit_buffer ab, void va)
90	{
91	struct common_audit_data *sa = va;
92
93	if (aad(sa)->mnt.type) {
94	audit_log_format(ab, " fstype=");
95	audit_log_untrustedstring(ab, aad(sa)->mnt.type);
96	}
97	if (aad(sa)->mnt.src_name) {
98	audit_log_format(ab, " srcname=");
99	audit_log_untrustedstring(ab, aad(sa)->mnt.src_name);
100	}
101	if (aad(sa)->mnt.trans) {
102	audit_log_format(ab, " trans=");
103	audit_log_untrustedstring(ab, aad(sa)->mnt.trans);
104	}
105	if (aad(sa)->mnt.flags) {
106	audit_log_format(ab, " flags=\"");
107	audit_mnt_flags(ab, aad(sa)->mnt.flags);
108	audit_log_format(ab, "\"");
109	}
110	if (aad(sa)->mnt.data) {
111	audit_log_format(ab, " options=");
112	audit_log_untrustedstring(ab, aad(sa)->mnt.data);
113	}
114	}
115
116	/**
117	* audit_mount - handle the auditing of mount operations
118	* @profile: the profile being enforced (NOT NULL)
119	* @op: operation being mediated (NOT NULL)
120	* @name: name of object being mediated (MAYBE NULL)
121	* @src_name: src_name of object being mediated (MAYBE_NULL)
122	* @type: type of filesystem (MAYBE_NULL)
123	* @trans: name of trans (MAYBE NULL)
124	* @flags: filesystem idependent mount flags
125	* @data: filesystem mount flags
126	* @request: permissions requested
127	* @perms: the permissions computed for the request (NOT NULL)
128	* @info: extra information message (MAYBE NULL)
129	* @error: 0 if operation allowed else failure error code
130	*
131	* Returns: %0 or error on failure
132	*/
133	static int audit_mount(struct aa_profile profile, const char op, const char *name,
134	const char src_name, const char type,
135	const char *trans, unsigned long flags,
136	const void data, u32 request, struct aa_perms perms,
137	const char *info, int error)
138	{
139	int audit_type = AUDIT_APPARMOR_AUTO;
140	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);
141
142	if (likely(!error)) {
143	u32 mask = perms->audit;
144
145	if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
146	mask = 0xffff;
147
148	/* mask off perms that are not being force audited */
149	request &= mask;
150
151	if (likely(!request))
152	return 0;
153	audit_type = AUDIT_APPARMOR_AUDIT;
154	} else {
155	/* only report permissions that were denied */
156	request = request & ~perms->allow;
157
158	if (request & perms->kill)
159	audit_type = AUDIT_APPARMOR_KILL;
160
161	/* quiet known rejects, assumes quiet and kill do not overlap */
162	if ((request & perms->quiet) &&
163	AUDIT_MODE(profile) != AUDIT_NOQUIET &&
164	AUDIT_MODE(profile) != AUDIT_ALL)
165	request &= ~perms->quiet;
166
167	if (!request)
168	return error;
169	}
170
171	aad(&sa)->name = name;
172	aad(&sa)->mnt.src_name = src_name;
173	aad(&sa)->mnt.type = type;
174	aad(&sa)->mnt.trans = trans;
175	aad(&sa)->mnt.flags = flags;
176	if (data && (perms->audit & AA_AUDIT_DATA))
177	aad(&sa)->mnt.data = data;
178	aad(&sa)->info = info;
179	aad(&sa)->error = error;
180
181	return aa_audit(audit_type, profile, &sa, audit_cb);
182	}
183
184	/**
185	* match_mnt_flags - Do an ordered match on mount flags
186	* @dfa: dfa to match against
187	* @state: state to start in
188	* @flags: mount flags to match against
189	*
190	* Mount flags are encoded as an ordered match. This is done instead of
191	* checking against a simple bitmask, to allow for logical operations
192	* on the flags.
193	*
194	* Returns: next state after flags match
195	*/
196	static unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state,
197	unsigned long flags)
198	{
199	unsigned int i;
200
201	for (i = 0; i <= 31 ; ++i) {
202	if ((1 << i) & flags)
203	state = aa_dfa_next(dfa, state, i + 1);
204	}
205
206	return state;
207	}
208
209	/**
210	* compute_mnt_perms - compute mount permission associated with @state
211	* @dfa: dfa to match against (NOT NULL)
212	* @state: state match finished in
213	*
214	* Returns: mount permissions
215	*/
216	static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa,
217	unsigned int state)
218	{
219	struct aa_perms perms;
220
221	perms.kill = 0;
222	perms.allow = dfa_user_allow(dfa, state);
223	perms.audit = dfa_user_audit(dfa, state);
224	perms.quiet = dfa_user_quiet(dfa, state);
225	perms.xindex = dfa_user_xindex(dfa, state);
226
227	return perms;
228	}
229
230	static const char *mnt_info_table[] = {
231	"match succeeded",
232	"failed mntpnt match",
233	"failed srcname match",
234	"failed type match",
235	"failed flags match",
236	"failed data match"
237	};
238
239	/*
240	* Returns 0 on success else element that match failed in, this is the
241	* index into the mnt_info_table above
242	*/
243	static int do_match_mnt(struct aa_dfa *dfa, unsigned int start,
244	const char mntpnt, const char devname,
245	const char *type, unsigned long flags,
246	void data, bool binary, struct aa_perms perms)
247	{
248	unsigned int state;
249
250	AA_BUG(!dfa);
251	AA_BUG(!perms);
252
253	state = aa_dfa_match(dfa, start, mntpnt);
254	state = aa_dfa_null_transition(dfa, state);
255	if (!state)
256	return 1;
257
258	if (devname)
259	state = aa_dfa_match(dfa, state, devname);
260	state = aa_dfa_null_transition(dfa, state);
261	if (!state)
262	return 2;
263
264	if (type)
265	state = aa_dfa_match(dfa, state, type);
266	state = aa_dfa_null_transition(dfa, state);
267	if (!state)
268	return 3;
269
270	state = match_mnt_flags(dfa, state, flags);
271	if (!state)
272	return 4;
273	*perms = compute_mnt_perms(dfa, state);
274	if (perms->allow & AA_MAY_MOUNT)
275	return 0;
276
277	/* only match data if not binary and the DFA flags data is expected */
278	if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
279	state = aa_dfa_null_transition(dfa, state);
280	if (!state)
281	return 4;
282
283	state = aa_dfa_match(dfa, state, data);
284	if (!state)
285	return 5;
286	*perms = compute_mnt_perms(dfa, state);
287	if (perms->allow & AA_MAY_MOUNT)
288	return 0;
289	}
290
291	/* failed at end of flags match */
292	return 4;
293	}
294
89faea0e JJ	295
	296	static int path_flags(struct aa_profile profile, const struct path path)
	297	{
	298	AA_BUG(!profile);
	299	AA_BUG(!path);
	300
	301	return profile->path_flags \|
	302	(S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0);
	303	}
	304
80594fc2	305	/**
89faea0e	306	* match_mnt_path_str - handle path matching for mount
80594fc2	307	* @profile: the confining profile
89faea0e JJ	308	* @mntpath: for the mntpnt (NOT NULL)
	309	* @buffer: buffer to be used to lookup mntpath
	310	* @devnme: string for the devname/src_name (MAY BE NULL OR ERRPTR)
80594fc2 JJ	311	* @type: string for the dev type (MAYBE NULL)
	312	* @flags: mount flags to match
	313	* @data: fs mount data (MAYBE NULL)
	314	* @binary: whether @data is binary
89faea0e	315	* @devinfo: error str if (IS_ERR(@devname))
80594fc2 JJ	316	*
	317	* Returns: 0 on success else error
	318	*/
89faea0e JJ	319	static int match_mnt_path_str(struct aa_profile profile, const struct path mntpath,
	320	char buffer, const char devname,
	321	const char *type, unsigned long flags,
	322	void data, bool binary, const char devinfo)
80594fc2 JJ	323	{
80594fc2 JJ	324	struct aa_perms perms = { };
89faea0e JJ	325	const char mntpnt = NULL, info = NULL;
89faea0e JJ	326	int pos, error;
80594fc2 JJ	327
80594fc2 JJ	328	AA_BUG(!profile);
89faea0e JJ	329	AA_BUG(!mntpath);
	330	AA_BUG(!buffer);
	331
	332	error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
	333	&mntpnt, &info, profile->disconnected);
	334	if (error)
	335	goto audit;
	336	if (IS_ERR(devname)) {
	337	error = PTR_ERR(devname);
	338	info = devinfo;
	339	goto audit;
	340	}
80594fc2	341
89faea0e	342	error = -EACCES;
80594fc2 JJ	343	pos = do_match_mnt(profile->policy.dfa,
	344	profile->policy.start[AA_CLASS_MOUNT],
	345	mntpnt, devname, type, flags, data, binary, &perms);
	346	if (pos) {
	347	info = mnt_info_table[pos];
	348	goto audit;
	349	}
	350	error = 0;
	351
	352	audit:
	353	return audit_mount(profile, OP_MOUNT, mntpnt, devname, type, NULL,
	354	flags, data, AA_MAY_MOUNT, &perms, info, error);
	355	}
	356
89faea0e JJ	357	/**
	358	* match_mnt - handle path matching for mount
	359	* @profile: the confining profile
	360	* @mntpath: for the mntpnt (NOT NULL)
	361	* @buffer: buffer to be used to lookup mntpath
	362	* @devpath: path devname/src_name (MAYBE NULL)
	363	* @devbuffer: buffer to be used to lookup devname/src_name
	364	* @type: string for the dev type (MAYBE NULL)
	365	* @flags: mount flags to match
	366	* @data: fs mount data (MAYBE NULL)
	367	* @binary: whether @data is binary
	368	*
	369	* Returns: 0 on success else error
	370	*/
	371	static int match_mnt(struct aa_profile profile, const struct path path,
	372	char buffer, struct path devpath, char *devbuffer,
	373	const char type, unsigned long flags, void data,
	374	bool binary)
80594fc2	375	{
89faea0e JJ	376	const char devname = NULL, info = NULL;
	377	int error = -EACCES;
	378
80594fc2	379	AA_BUG(!profile);
89faea0e	380	AA_BUG(devpath && !devbuffer);
80594fc2	381
89faea0e JJ	382	if (devpath) {
	383	error = aa_path_name(devpath, path_flags(profile, devpath),
	384	devbuffer, &devname, &info,
	385	profile->disconnected);
	386	if (error)
	387	devname = ERR_PTR(error);
	388	}
	389
	390	return match_mnt_path_str(profile, path, buffer, devname, type, flags,
	391	data, binary, info);
80594fc2 JJ	392	}
	393
	394	int aa_remount(struct aa_label label, const struct path path,
	395	unsigned long flags, void *data)
	396	{
	397	struct aa_profile *profile;
80594fc2 JJ	398	char *buffer = NULL;
	399	bool binary;
	400	int error;
	401
	402	AA_BUG(!label);
	403	AA_BUG(!path);
	404
	405	binary = path->dentry->d_sb->s_type->fs_flags & FS_BINARY_MOUNTDATA;
	406
	407	get_buffers(buffer);
80594fc2	408	error = fn_for_each_confined(label, profile,
89faea0e JJ	409	match_mnt(profile, path, buffer, NULL, NULL, NULL,
89faea0e JJ	410	flags, data, binary));
80594fc2 JJ	411	put_buffers(buffer);
	412
	413	return error;
	414	}
	415
	416	int aa_bind_mount(struct aa_label label, const struct path path,
	417	const char *dev_name, unsigned long flags)
	418	{
	419	struct aa_profile *profile;
	420	char buffer = NULL, old_buffer = NULL;
80594fc2 JJ	421	struct path old_path;
	422	int error;
	423
	424	AA_BUG(!label);
	425	AA_BUG(!path);
	426
	427	if (!dev_name \|\| !*dev_name)
	428	return -EINVAL;
	429
	430	flags &= MS_REC \| MS_BIND;
	431
	432	error = kern_path(dev_name, LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT, &old_path);
	433	if (error)
	434	return error;
	435
	436	get_buffers(buffer, old_buffer);
80594fc2	437	error = fn_for_each_confined(label, profile,
89faea0e JJ	438	match_mnt(profile, path, buffer, &old_path, old_buffer,
89faea0e JJ	439	NULL, flags, NULL, false));
80594fc2	440	put_buffers(buffer, old_buffer);
89faea0e	441	path_put(&old_path);
80594fc2 JJ	442
80594fc2 JJ	443	return error;
80594fc2 JJ	444	}
	445
	446	int aa_mount_change_type(struct aa_label label, const struct path path,
	447	unsigned long flags)
	448	{
	449	struct aa_profile *profile;
	450	char *buffer = NULL;
80594fc2 JJ	451	int error;
	452
	453	AA_BUG(!label);
	454	AA_BUG(!path);
	455
	456	/* These are the flags allowed by do_change_type() */
	457	flags &= (MS_REC \| MS_SILENT \| MS_SHARED \| MS_PRIVATE \| MS_SLAVE \|
	458	MS_UNBINDABLE);
	459
	460	get_buffers(buffer);
80594fc2	461	error = fn_for_each_confined(label, profile,
89faea0e JJ	462	match_mnt(profile, path, buffer, NULL, NULL, NULL,
89faea0e JJ	463	flags, NULL, false));
80594fc2 JJ	464	put_buffers(buffer);
	465
	466	return error;
	467	}
	468
	469	int aa_move_mount(struct aa_label label, const struct path path,
	470	const char *orig_name)
	471	{
	472	struct aa_profile *profile;
	473	char buffer = NULL, old_buffer = NULL;
80594fc2 JJ	474	struct path old_path;
	475	int error;
	476
	477	AA_BUG(!label);
	478	AA_BUG(!path);
	479
	480	if (!orig_name \|\| !*orig_name)
	481	return -EINVAL;
	482
	483	error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);
	484	if (error)
	485	return error;
	486
	487	get_buffers(buffer, old_buffer);
80594fc2	488	error = fn_for_each_confined(label, profile,
89faea0e JJ	489	match_mnt(profile, path, buffer, &old_path, old_buffer,
89faea0e JJ	490	NULL, MS_MOVE, NULL, false));
80594fc2	491	put_buffers(buffer, old_buffer);
89faea0e	492	path_put(&old_path);
80594fc2 JJ	493
80594fc2 JJ	494	return error;
80594fc2 JJ	495	}
80594fc2 JJ	496
89faea0e	497	int aa_new_mount(struct aa_label label, const char dev_name,
80594fc2 JJ	498	const struct path path, const char type, unsigned long flags,
	499	void *data)
	500	{
	501	struct aa_profile *profile;
	502	char buffer = NULL, dev_buffer = NULL;
80594fc2 JJ	503	bool binary = true;
	504	int error;
	505	int requires_dev = 0;
89faea0e	506	struct path tmp_path, *dev_path = NULL;
80594fc2 JJ	507
	508	AA_BUG(!label);
	509	AA_BUG(!path);
	510
80594fc2 JJ	511	if (type) {
	512	struct file_system_type *fstype;
	513	fstype = get_fs_type(type);
	514	if (!fstype)
	515	return -ENODEV;
	516	binary = fstype->fs_flags & FS_BINARY_MOUNTDATA;
	517	requires_dev = fstype->fs_flags & FS_REQUIRES_DEV;
	518	put_filesystem(fstype);
	519
	520	if (requires_dev) {
	521	if (!dev_name \|\| !*dev_name)
	522	return -ENOENT;
	523
89faea0e	524	error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path);
80594fc2 JJ	525	if (error)
80594fc2 JJ	526	return error;
89faea0e	527	dev_path = &tmp_path;
80594fc2 JJ	528	}
	529	}
	530
	531	get_buffers(buffer, dev_buffer);
89faea0e JJ	532	if (dev_path) {
	533	error = fn_for_each_confined(label, profile,
	534	match_mnt(profile, path, buffer, dev_path, dev_buffer,
	535	type, flags, data, binary));
	536	} else {
	537	error = fn_for_each_confined(label, profile,
	538	match_mnt_path_str(profile, path, buffer, dev_name,
	539	type, flags, data, binary, NULL));
80594fc2	540	}
80594fc2	541	put_buffers(buffer, dev_buffer);
89faea0e JJ	542	if (dev_path)
89faea0e JJ	543	path_put(dev_path);
80594fc2 JJ	544
80594fc2 JJ	545	return error;
80594fc2 JJ	546	}
80594fc2 JJ	547
89faea0e JJ	548	static int profile_umount(struct aa_profile profile, struct path path,
89faea0e JJ	549	char *buffer)
80594fc2 JJ	550	{
80594fc2 JJ	551	struct aa_perms perms = { };
89faea0e	552	const char name = NULL, info = NULL;
80594fc2	553	unsigned int state;
89faea0e	554	int error;
80594fc2 JJ	555
80594fc2 JJ	556	AA_BUG(!profile);
89faea0e JJ	557	AA_BUG(!path);
	558
	559	error = aa_path_name(path, path_flags(profile, path), buffer, &name,
	560	&info, profile->disconnected);
	561	if (error)
	562	goto audit;
80594fc2 JJ	563
	564	state = aa_dfa_match(profile->policy.dfa,
	565	profile->policy.start[AA_CLASS_MOUNT],
	566	name);
	567	perms = compute_mnt_perms(profile->policy.dfa, state);
	568	if (AA_MAY_UMOUNT & ~perms.allow)
89faea0e	569	error = -EACCES;
80594fc2	570
89faea0e	571	audit:
80594fc2	572	return audit_mount(profile, OP_UMOUNT, name, NULL, NULL, NULL, 0, NULL,
89faea0e	573	AA_MAY_UMOUNT, &perms, info, error);
80594fc2 JJ	574	}
	575
	576	int aa_umount(struct aa_label label, struct vfsmount mnt, int flags)
	577	{
	578	struct aa_profile *profile;
	579	char *buffer = NULL;
80594fc2 JJ	580	int error;
	581	struct path path = { mnt, mnt->mnt_root };
	582
	583	AA_BUG(!label);
	584	AA_BUG(!mnt);
	585
	586	get_buffers(buffer);
80594fc2	587	error = fn_for_each_confined(label, profile,
89faea0e	588	profile_umount(profile, &path, buffer));
80594fc2 JJ	589	put_buffers(buffer);
	590
	591	return error;
	592	}
	593
8871ecee JJ	594	/* helper fn for transition on pivotroot
	595	*
	596	* Returns: label for transition or ERR_PTR. Does not return NULL
	597	*/
	598	static struct aa_label build_pivotroot(struct aa_profile profile,
89faea0e JJ	599	struct path *new_path,
	600	char *new_buffer,
	601	struct path *old_path,
	602	char *old_buffer)
80594fc2	603	{
89faea0e	604	const char old_name, new_name = NULL, *info = NULL;
80594fc2	605	const char *trans_name = NULL;
89faea0e	606	struct aa_label *target = NULL;
80594fc2	607	struct aa_perms perms = { };
80594fc2	608	unsigned int state;
89faea0e	609	int error;
80594fc2 JJ	610
80594fc2 JJ	611	AA_BUG(!profile);
89faea0e JJ	612	AA_BUG(!new_path);
	613	AA_BUG(!old_path);
	614
	615	error = aa_path_name(old_path, path_flags(profile, old_path),
	616	old_buffer, &old_name, &info,
	617	profile->disconnected);
	618	if (error)
	619	goto audit;
	620	error = aa_path_name(new_path, path_flags(profile, new_path),
	621	new_buffer, &new_name, &info,
	622	profile->disconnected);
	623	if (error)
	624	goto audit;
80594fc2	625
89faea0e	626	error = -EACCES;
80594fc2 JJ	627	state = aa_dfa_match(profile->policy.dfa,
	628	profile->policy.start[AA_CLASS_MOUNT],
	629	new_name);
	630	state = aa_dfa_null_transition(profile->policy.dfa, state);
	631	state = aa_dfa_match(profile->policy.dfa, state, old_name);
	632	perms = compute_mnt_perms(profile->policy.dfa, state);
	633
	634	if (AA_MAY_PIVOTROOT & perms.allow) {
8871ecee	635	error = 0;
80594fc2 JJ	636	if ((perms.xindex & AA_X_TYPE_MASK) == AA_X_TABLE) {
	637	target = x_table_lookup(profile, perms.xindex,
	638	&trans_name);
	639	if (!target)
	640	error = -ENOENT;
8871ecee	641	}
80594fc2 JJ	642	}
80594fc2 JJ	643
89faea0e	644	audit:
80594fc2 JJ	645	error = audit_mount(profile, OP_PIVOTROOT, new_name, old_name,
	646	NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT,
	647	&perms, info, error);
8871ecee	648	if (error) {
80594fc2	649	aa_put_label(target);
8871ecee JJ	650	return ERR_PTR(error);
	651	} else if (target)
	652	return target;
80594fc2	653
8871ecee	654	return aa_get_label(&profile->label);
80594fc2 JJ	655	}
	656
	657	int aa_pivotroot(struct aa_label label, const struct path old_path,
	658	const struct path *new_path)
	659	{
	660	struct aa_profile *profile;
	661	struct aa_label *target = NULL;
89faea0e	662	char old_buffer = NULL, new_buffer = NULL, *info = NULL;
80594fc2 JJ	663	int error;
	664
	665	AA_BUG(!label);
	666	AA_BUG(!old_path);
	667	AA_BUG(!new_path);
	668
	669	get_buffers(old_buffer, new_buffer);
8871ecee	670	target = fn_label_build(label, profile, GFP_ATOMIC,
89faea0e JJ	671	build_pivotroot(profile, new_path, new_buffer,
89faea0e JJ	672	old_path, old_buffer));
8871ecee JJ	673	if (!target) {
	674	info = "label build failed";
	675	error = -ENOMEM;
	676	goto fail;
	677	} else if (!IS_ERR(target)) {
	678	error = aa_replace_current_label(target);
	679	if (error) {
	680	/* TODO: audit target */
	681	aa_put_label(target);
	682	goto out;
	683	}
	684	} else
	685	/* already audited error */
	686	error = PTR_ERR(target);
80594fc2 JJ	687	out:
	688	put_buffers(old_buffer, new_buffer);
	689
80594fc2 JJ	690	return error;
80594fc2 JJ	691
8871ecee	692	fail:
89faea0e	693	/* TODO: add back in auditing of new_name and old_name */
80594fc2	694	error = fn_for_each(label, profile,
89faea0e JJ	695	audit_mount(profile, OP_PIVOTROOT, NULL /new_name /,
89faea0e JJ	696	NULL /* old_name */,
80594fc2 JJ	697	NULL, NULL,
	698	0, NULL, AA_MAY_PIVOTROOT, &nullperms, info,
	699	error));
	700	goto out;
	701	}