// 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){	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 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(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 = {		.allow = dfa_user_allow(dfa, state),		.audit = dfa_user_audit(dfa, state),		.quiet = dfa_user_quiet(dfa, state),		.xindex = dfa_user_xindex(dfa, state),	}; 	return perms;} static const char * const 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); 	if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))		return 0; 	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);		devname = NULL;		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, const 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 (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))		return 0; 	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; 	buffer = aa_get_buffer(false);	if (!buffer)		return -ENOMEM;	error = fn_for_each_confined(label, profile,			match_mnt(profile, path, buffer, NULL, NULL, NULL,				  flags, data, binary));	aa_put_buffer(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; 	buffer = aa_get_buffer(false);	old_buffer = aa_get_buffer(false);	error = -ENOMEM;	if (!buffer || !old_buffer)		goto out; 	error = fn_for_each_confined(label, profile,			match_mnt(profile, path, buffer, &old_path, old_buffer,				  NULL, flags, NULL, false));out:	aa_put_buffer(buffer);	aa_put_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); 	buffer = aa_get_buffer(false);	if (!buffer)		return -ENOMEM;	error = fn_for_each_confined(label, profile,			match_mnt(profile, path, buffer, NULL, NULL, NULL,				  flags, NULL, false));	aa_put_buffer(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;

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