// 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"  #define DEFINE_AUDIT_MOUNT(NAME, OP, CRED)				\	DEFINE_AUDIT_DATA(NAME, LSM_AUDIT_DATA_NONE, AA_CLASS_MOUNT, OP);\	NAME.subj_cred = (CRED) 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_NOSYMFOLLOW)		audit_log_format(ab, ", nosymfollow");	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;	struct apparmor_audit_data *ad = aad(sa); 	if (ad->mnt.type) {		audit_log_format(ab, " fstype=");		audit_log_untrustedstring(ab, ad->mnt.type);	}	if (ad->mnt.src_name) {		audit_log_format(ab, " srcname=");		audit_log_untrustedstring(ab, ad->mnt.src_name);	}	if (ad->mnt.trans) {		audit_log_format(ab, " trans=");		audit_log_untrustedstring(ab, ad->mnt.trans);	}	if (ad->mnt.flags) {		audit_log_format(ab, " flags=\"");		audit_mnt_flags(ab, ad->mnt.flags);		audit_log_format(ab, "\"");	}	if (ad->mnt.data) {		audit_log_format(ab, " options=");		audit_log_untrustedstring(ab, ad->mnt.data);	}} /** * 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(const struct aa_dfa *dfa, aa_state_t 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;} static const char * const mnt_info_table[] = {	"match succeeded",	"failed mntpnt match",	"failed srcname match",	"failed type match",	"failed flags match",	"failed data match",	"failed perms check"}; /* * 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){	aa_state_t state; 	AA_BUG(!policy);	AA_BUG(!policy->dfa);	AA_BUG(!policy->perms);	AA_BUG(!perms); 	state = aa_dfa_match(policy->dfa, start, mntpnt);	state = aa_dfa_null_transition(policy->dfa, state);	if (!state)		return 1; 	if (devname)		state = aa_dfa_match(policy->dfa, state, devname);	state = aa_dfa_null_transition(policy->dfa, state);	if (!state)		return 2; 	if (type)		state = aa_dfa_match(policy->dfa, state, type);	state = aa_dfa_null_transition(policy->dfa, state);	if (!state)		return 3; 	state = match_mnt_flags(policy->dfa, state, flags);	if (!state)		return 4;	*perms = *aa_lookup_perms(policy, 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(policy->dfa, state);		if (!state)			return 4; 		state = aa_dfa_match(policy->dfa, state, data);		if (!state)			return 5;		*perms = *aa_lookup_perms(policy, state);		if (perms->allow & AA_MAY_MOUNT)			return 0;	} 	/* failed at perms check, don't confuse with flags match */	return 6;}  static int path_flags(const 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 * @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)) * @ad: apparmor audit data structure * * 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 apparmor_audit_data *ad){	struct aa_perms perms = { };	const char *mntpnt = NULL;	struct aa_ruleset *rules = profile->label.rules[0];	int pos, error; 	AA_BUG(!profile);	AA_BUG(!mntpath);	AA_BUG(!buffer); 	if (!RULE_MEDIATES(rules, AA_CLASS_MOUNT))		return 0; 	ad->mnt.type = type; 	error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,			     &mntpnt, &ad->info, profile->disconnected);	if (error)		return aa_audit_perm_error(&profile->label, AA_MAY_MOUNT,					   error, ad, audit_cb);	ad->name = mntpnt; 	if (IS_ERR(devname)) {		error = PTR_ERR(devname);		ad->info = devinfo;		return aa_audit_perm_error(&profile->label, AA_MAY_MOUNT,					   error, ad, audit_cb);	}	ad->mnt.src_name = devname; 	pos = do_match_mnt(rules->policy,			   rules->policy->start[AA_CLASS_MOUNT],			   mntpnt, devname, type, flags, data, binary, &perms);	if (pos)		ad->info = mnt_info_table[pos]; 	aa_apply_modes_to_perms(profile, &perms);	if (data && !binary && (perms.audit & AA_AUDIT_DATA))		ad->mnt.data = data;	return aa_check_perms(profile, &perms, AA_MAY_MOUNT, ad, audit_cb);} /** * match_mnt - handle path matching for mount * @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 * @ad: apparmor audit data structure * * 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, struct apparmor_audit_data *ad){	const char *devname = NULL, *info = NULL;	struct aa_ruleset *rules = profile->label.rules[0];	int error = -EACCES; 	AA_BUG(!profile);	AA_BUG(devpath && !devbuffer); 	if (!RULE_MEDIATES(rules, 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, ad);} int aa_remount(const struct cred *subj_cred,	       struct aa_label *label, const struct path *path,	       unsigned long flags, void *data){	struct aa_profile *profile;	char *buffer = NULL;	bool binary;	int error;	DEFINE_AUDIT_MOUNT(ad, OP_MOUNT, subj_cred);	ad.mnt.flags = flags; 	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(label, profile,			match_mnt(profile, path, buffer, NULL, NULL, NULL,				  flags, data, binary, &ad));	aa_put_buffer(buffer); 	return error;} int aa_bind_mount(const struct cred *subj_cred,		  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;	DEFINE_AUDIT_MOUNT(ad, OP_MOUNT, subj_cred); 	AA_BUG(!label);	AA_BUG(!path); 	if (!dev_name || !*dev_name)		return -EINVAL; 	flags &= MS_REC | MS_BIND;	ad.mnt.flags = flags; 	error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);	if (error)		return aa_audit_perm_error(label, AA_MAY_MOUNT, error, &ad,			audit_cb); 	buffer = aa_get_buffer(false);	old_buffer = aa_get_buffer(false);	error = -ENOMEM;	if (!buffer || !old_buffer)		goto out; 	error = fn_for_each(label, profile,			match_mnt(profile, path, buffer, &old_path,				  old_buffer, NULL, flags, NULL, false, &ad));out:	aa_put_buffer(buffer);	aa_put_buffer(old_buffer);	path_put(&old_path); 	return error;} int aa_mount_change_type(const struct cred *subj_cred,			 struct aa_label *label, const struct path *path,			 unsigned long flags){	struct aa_profile *profile;	char *buffer = NULL;	int error;	DEFINE_AUDIT_MOUNT(ad, OP_MOUNT, subj_cred); 	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);	ad.mnt.flags = flags; 	buffer = aa_get_buffer(false);	if (!buffer)		return -ENOMEM;	error = fn_for_each(label, profile,			match_mnt(profile, path, buffer, NULL, NULL, NULL,				  flags, NULL, false, &ad));	aa_put_buffer(buffer); 	return error;} int aa_move_mount(const struct cred *subj_cred,		  struct aa_label *label, const struct path *from_path,		  const struct path *to_path){	struct aa_profile *profile;	char *to_buffer = NULL, *from_buffer = NULL;	int error;	DEFINE_AUDIT_MOUNT(ad, OP_MOUNT, subj_cred);	ad.mnt.flags = MS_MOVE; 	AA_BUG(!label);	AA_BUG(!from_path);	AA_BUG(!to_path); 	to_buffer = aa_get_buffer(false);	from_buffer = aa_get_buffer(false);	error = -ENOMEM;	if (!to_buffer || !from_buffer)		goto out; 	if (!our_mnt(from_path->mnt))		/* moving a mount detached from the namespace */		from_path = NULL;	error = fn_for_each(label, profile,			match_mnt(profile, to_path, to_buffer, from_path,				  from_buffer, NULL, MS_MOVE, NULL, false,				  &ad));out:	aa_put_buffer(to_buffer);	aa_put_buffer(from_buffer); 	return error;} int aa_move_mount_old(const struct cred *subj_cred, struct aa_label *label,		      const struct path *path, const char *orig_name){	struct path old_path;	int error; 	if (!orig_name || !*orig_name)		return -EINVAL;	error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);	if (error)		return error; 	error = aa_move_mount(subj_cred, label, &old_path, path);	path_put(&old_path); 	return error;} 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){	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;	DEFINE_AUDIT_MOUNT(ad, OP_MOUNT, subj_cred);	ad.mnt.flags = flags; 	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);

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