[mirror_ubuntu-bionic-kernel.git] / fs / attr.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/attr.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  changes by Thomas Schoebel-Theuer
 */

#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/sched/signal.h>
#include <linux/capability.h>
#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/ima.h>

static bool chown_ok(const struct inode *inode, kuid_t uid)
{
	if (uid_eq(current_fsuid(), inode->i_uid) &&
	    uid_eq(uid, inode->i_uid))
		return true;
	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
		return true;
	if (ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
		return true;
	return false;
}

static bool chgrp_ok(const struct inode *inode, kgid_t gid)
{
	if (uid_eq(current_fsuid(), inode->i_uid) &&
	    (in_group_p(gid) || gid_eq(gid, inode->i_gid)))
		return true;
	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
		return true;
	if (ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
		return true;
	return false;
}

/**
 * setattr_prepare - check if attribute changes to a dentry are allowed
 * @dentry:	dentry to check
 * @attr:	attributes to change
 *
 * Check if we are allowed to change the attributes contained in @attr
 * in the given dentry.  This includes the normal unix access permission
 * checks, as well as checks for rlimits and others. The function also clears
 * SGID bit from mode if user is not allowed to set it. Also file capabilities
 * and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
 *
 * Should be called as the first thing in ->setattr implementations,
 * possibly after taking additional locks.
 */
int setattr_prepare(struct dentry *dentry, struct iattr *attr)
{
	struct inode *inode = d_inode(dentry);
	unsigned int ia_valid = attr->ia_valid;

	/*
	 * First check size constraints.  These can't be overriden using
	 * ATTR_FORCE.
	 */
	if (ia_valid & ATTR_SIZE) {
		int error = inode_newsize_ok(inode, attr->ia_size);
		if (error)
			return error;
	}

	/* If force is set do it anyway. */
	if (ia_valid & ATTR_FORCE)
		goto kill_priv;

	/* Make sure a caller can chown. */
	if ((ia_valid & ATTR_UID) && !chown_ok(inode, attr->ia_uid))
		return -EPERM;

	/* Make sure caller can chgrp. */
	if ((ia_valid & ATTR_GID) && !chgrp_ok(inode, attr->ia_gid))
		return -EPERM;

	/* Make sure a caller can chmod. */
	if (ia_valid & ATTR_MODE) {
		if (!inode_owner_or_capable(inode))
			return -EPERM;
		/* Also check the setgid bit! */
		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
				inode->i_gid) &&
		    !capable_wrt_inode_uidgid(inode, CAP_FSETID))
			attr->ia_mode &= ~S_ISGID;
	}

	/* Check for setting the inode time. */
	if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
		if (!inode_owner_or_capable(inode))
			return -EPERM;
	}

kill_priv:
	/* User has permission for the change */
	if (ia_valid & ATTR_KILL_PRIV) {
		int error;

		error = security_inode_killpriv(dentry);
		if (error)
			return error;
	}

	return 0;
}
EXPORT_SYMBOL(setattr_prepare);

/**
 * inode_newsize_ok - may this inode be truncated to a given size
 * @inode:	the inode to be truncated
 * @offset:	the new size to assign to the inode
 * @Returns:	0 on success, -ve errno on failure
 *
 * inode_newsize_ok must be called with i_mutex held.
 *
 * inode_newsize_ok will check filesystem limits and ulimits to check that the
 * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
 * when necessary. Caller must not proceed with inode size change if failure is
 * returned. @inode must be a file (not directory), with appropriate
 * permissions to allow truncate (inode_newsize_ok does NOT check these
 * conditions).
 */
int inode_newsize_ok(const struct inode *inode, loff_t offset)
{
	if (inode->i_size < offset) {
		unsigned long limit;

		limit = rlimit(RLIMIT_FSIZE);
		if (limit != RLIM_INFINITY && offset > limit)
			goto out_sig;
		if (offset > inode->i_sb->s_maxbytes)
			goto out_big;
	} else {
		/*
		 * truncation of in-use swapfiles is disallowed - it would
		 * cause subsequent swapout to scribble on the now-freed
		 * blocks.
		 */
		if (IS_SWAPFILE(inode))
			return -ETXTBSY;
	}

	return 0;
out_sig:
	send_sig(SIGXFSZ, current, 0);
out_big:
	return -EFBIG;
}
EXPORT_SYMBOL(inode_newsize_ok);

/**
 * setattr_copy - copy simple metadata updates into the generic inode
 * @inode:	the inode to be updated
 * @attr:	the new attributes
 *
 * setattr_copy must be called with i_mutex held.
 *
 * setattr_copy updates the inode's metadata with that specified
 * in attr. Noticeably missing is inode size update, which is more complex
 * as it requires pagecache updates.
 *
 * The inode is not marked as dirty after this operation. The rationale is
 * that for "simple" filesystems, the struct inode is the inode storage.
 * The caller is free to mark the inode dirty afterwards if needed.
 */
void setattr_copy(struct inode *inode, const struct iattr *attr)
{
	unsigned int ia_valid = attr->ia_valid;

	if (ia_valid & ATTR_UID)
		inode->i_uid = attr->ia_uid;
	if (ia_valid & ATTR_GID)
		inode->i_gid = attr->ia_gid;
	if (ia_valid & ATTR_ATIME)
		inode->i_atime = timespec_trunc(attr->ia_atime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MTIME)
		inode->i_mtime = timespec_trunc(attr->ia_mtime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_CTIME)
		inode->i_ctime = timespec_trunc(attr->ia_ctime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MODE) {
		umode_t mode = attr->ia_mode;

		if (!in_group_p(inode->i_gid) &&
		    !capable_wrt_inode_uidgid(inode, CAP_FSETID))
			mode &= ~S_ISGID;
		inode->i_mode = mode;
	}
}
EXPORT_SYMBOL(setattr_copy);

/**
 * notify_change - modify attributes of a filesytem object
 * @dentry:	object affected
 * @iattr:	new attributes
 * @delegated_inode: returns inode, if the inode is delegated
 *
 * The caller must hold the i_mutex on the affected object.
 *
 * If notify_change discovers a delegation in need of breaking,
 * it will return -EWOULDBLOCK and return a reference to the inode in
 * delegated_inode.  The caller should then break the delegation and
 * retry.  Because breaking a delegation may take a long time, the
 * caller should drop the i_mutex before doing so.
 *
 * Alternatively, a caller may pass NULL for delegated_inode.  This may
 * be appropriate for callers that expect the underlying filesystem not
 * to be NFS exported.  Also, passing NULL is fine for callers holding
 * the file open for write, as there can be no conflicting delegation in
 * that case.
 */
int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
{
	struct inode *inode = dentry->d_inode;
	umode_t mode = inode->i_mode;
	int error;
	struct timespec now;
	unsigned int ia_valid = attr->ia_valid;

	WARN_ON_ONCE(!inode_is_locked(inode));

	if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
		if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
			return -EPERM;
	}

	/*
	 * If utimes(2) and friends are called with times == NULL (or both
	 * times are UTIME_NOW), then we need to check for write permission
	 */
	if (ia_valid & ATTR_TOUCH) {
		if (IS_IMMUTABLE(inode))
			return -EPERM;

		if (!inode_owner_or_capable(inode)) {
			error = inode_permission(inode, MAY_WRITE);
			if (error)
				return error;
		}
	}

	if ((ia_valid & ATTR_MODE)) {
		umode_t amode = attr->ia_mode;
		/* Flag setting protected by i_mutex */
		if (is_sxid(amode))
			inode->i_flags &= ~S_NOSEC;
	}

	now = current_time(inode);

	attr->ia_ctime = now;
	if (!(ia_valid & ATTR_ATIME_SET))
		attr->ia_atime = now;
	if (!(ia_valid & ATTR_MTIME_SET))
		attr->ia_mtime = now;
	if (ia_valid & ATTR_KILL_PRIV) {
		error = security_inode_need_killpriv(dentry);
		if (error < 0)
			return error;
		if (error == 0)
			ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
	}

	/*
	 * We now pass ATTR_KILL_S*ID to the lower level setattr function so
	 * that the function has the ability to reinterpret a mode change
	 * that's due to these bits. This adds an implicit restriction that
	 * no function will ever call notify_change with both ATTR_MODE and
	 * ATTR_KILL_S*ID set.
	 */
	if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
	    (ia_valid & ATTR_MODE))
		BUG();

	if (ia_valid & ATTR_KILL_SUID) {
		if (mode & S_ISUID) {
			ia_valid = attr->ia_valid |= ATTR_MODE;
			attr->ia_mode = (inode->i_mode & ~S_ISUID);
		}
	}
	if (ia_valid & ATTR_KILL_SGID) {
		if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
			if (!(ia_valid & ATTR_MODE)) {
				ia_valid = attr->ia_valid |= ATTR_MODE;
				attr->ia_mode = inode->i_mode;
			}
			attr->ia_mode &= ~S_ISGID;
		}
	}
	if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
		return 0;

	/*
	 * Verify that uid/gid changes are valid in the target
	 * namespace of the superblock.
	 */
	if (ia_valid & ATTR_UID &&
	    !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid))
		return -EOVERFLOW;
	if (ia_valid & ATTR_GID &&
	    !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid))
		return -EOVERFLOW;

	/* Don't allow modifications of files with invalid uids or
	 * gids unless those uids & gids are being made valid.
	 */
	if (!(ia_valid & ATTR_UID) && !uid_valid(inode->i_uid))
		return -EOVERFLOW;
	if (!(ia_valid & ATTR_GID) && !gid_valid(inode->i_gid))
		return -EOVERFLOW;

	error = security_inode_setattr(dentry, attr);
	if (error)
		return error;
	error = try_break_deleg(inode, delegated_inode);
	if (error)
		return error;

	if (inode->i_op->setattr)
		error = inode->i_op->setattr(dentry, attr);
	else
		error = simple_setattr(dentry, attr);

	if (!error) {
		fsnotify_change(dentry, ia_valid);
		ima_inode_post_setattr(dentry);
		evm_inode_post_setattr(dentry, ia_valid);
	}

	return error;
}
EXPORT_SYMBOL(notify_change);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/attr.c
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	* changes by Thomas Schoebel-Theuer
	7	*/
	8
630d9c47	9	#include <linux/export.h>
1da177e4 LT	10	#include <linux/time.h>
	11	#include <linux/mm.h>
	12	#include <linux/string.h>
3f07c014	13	#include <linux/sched/signal.h>
16f7e0fe	14	#include <linux/capability.h>
0eeca283	15	#include <linux/fsnotify.h>
1da177e4	16	#include <linux/fcntl.h>
1da177e4	17	#include <linux/security.h>
975d2943	18	#include <linux/evm.h>
9957a504	19	#include <linux/ima.h>
1da177e4	20
5e13dab9 EB	21	static bool chown_ok(const struct inode *inode, kuid_t uid)
	22	{
	23	if (uid_eq(current_fsuid(), inode->i_uid) &&
	24	uid_eq(uid, inode->i_uid))
	25	return true;
	26	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
	27	return true;
	28	if (ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
	29	return true;
	30	return false;
	31	}
	32
	33	static bool chgrp_ok(const struct inode *inode, kgid_t gid)
	34	{
	35	if (uid_eq(current_fsuid(), inode->i_uid) &&
	36	(in_group_p(gid) \|\| gid_eq(gid, inode->i_gid)))
	37	return true;
	38	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
	39	return true;
	40	if (ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
	41	return true;
	42	return false;
	43	}
	44
2c27c65e	45	/**
31051c85 JK	46	* setattr_prepare - check if attribute changes to a dentry are allowed
31051c85 JK	47	* @dentry: dentry to check
2c27c65e CH	48	* @attr: attributes to change
	49	*
	50	* Check if we are allowed to change the attributes contained in @attr
31051c85 JK	51	* in the given dentry. This includes the normal unix access permission
	52	* checks, as well as checks for rlimits and others. The function also clears
	53	* SGID bit from mode if user is not allowed to set it. Also file capabilities
	54	* and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
2c27c65e CH	55	*
	56	* Should be called as the first thing in ->setattr implementations,
	57	* possibly after taking additional locks.
	58	*/
31051c85	59	int setattr_prepare(struct dentry dentry, struct iattr attr)
1da177e4	60	{
31051c85	61	struct inode *inode = d_inode(dentry);
1da177e4 LT	62	unsigned int ia_valid = attr->ia_valid;
1da177e4 LT	63
2c27c65e CH	64	/*
	65	* First check size constraints. These can't be overriden using
	66	* ATTR_FORCE.
	67	*/
	68	if (ia_valid & ATTR_SIZE) {
	69	int error = inode_newsize_ok(inode, attr->ia_size);
	70	if (error)
	71	return error;
	72	}
	73
1da177e4 LT	74	/* If force is set do it anyway. */
1da177e4 LT	75	if (ia_valid & ATTR_FORCE)
030b533c	76	goto kill_priv;
1da177e4 LT	77
1da177e4 LT	78	/* Make sure a caller can chown. */
5e13dab9	79	if ((ia_valid & ATTR_UID) && !chown_ok(inode, attr->ia_uid))
2c27c65e	80	return -EPERM;
1da177e4 LT	81
1da177e4 LT	82	/* Make sure caller can chgrp. */
5e13dab9	83	if ((ia_valid & ATTR_GID) && !chgrp_ok(inode, attr->ia_gid))
2c27c65e	84	return -EPERM;
1da177e4 LT	85
	86	/* Make sure a caller can chmod. */
	87	if (ia_valid & ATTR_MODE) {
2e149670	88	if (!inode_owner_or_capable(inode))
2c27c65e	89	return -EPERM;
1da177e4 LT	90	/* Also check the setgid bit! */
1da177e4 LT	91	if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
7fa294c8	92	inode->i_gid) &&
23adbe12	93	!capable_wrt_inode_uidgid(inode, CAP_FSETID))
1da177e4 LT	94	attr->ia_mode &= ~S_ISGID;
	95	}
	96
	97	/* Check for setting the inode time. */
9767d749	98	if (ia_valid & (ATTR_MTIME_SET \| ATTR_ATIME_SET \| ATTR_TIMES_SET)) {
2e149670	99	if (!inode_owner_or_capable(inode))
2c27c65e	100	return -EPERM;
1da177e4	101	}
2c27c65e	102
030b533c JK	103	kill_priv:
	104	/* User has permission for the change */
	105	if (ia_valid & ATTR_KILL_PRIV) {
	106	int error;
	107
	108	error = security_inode_killpriv(dentry);
	109	if (error)
	110	return error;
	111	}
	112
2c27c65e	113	return 0;
1da177e4	114	}
31051c85	115	EXPORT_SYMBOL(setattr_prepare);
1da177e4	116
25d9e2d1	117	/**
	118	* inode_newsize_ok - may this inode be truncated to a given size
	119	* @inode: the inode to be truncated
	120	* @offset: the new size to assign to the inode
	121	* @Returns: 0 on success, -ve errno on failure
	122	*
7bb46a67	123	* inode_newsize_ok must be called with i_mutex held.
7bb46a67	124	*
25d9e2d1	125	* inode_newsize_ok will check filesystem limits and ulimits to check that the
	126	* new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
	127	* when necessary. Caller must not proceed with inode size change if failure is
	128	* returned. @inode must be a file (not directory), with appropriate
	129	* permissions to allow truncate (inode_newsize_ok does NOT check these
	130	* conditions).
25d9e2d1	131	*/
	132	int inode_newsize_ok(const struct inode *inode, loff_t offset)
	133	{
	134	if (inode->i_size < offset) {
	135	unsigned long limit;
	136
d554ed89	137	limit = rlimit(RLIMIT_FSIZE);
25d9e2d1	138	if (limit != RLIM_INFINITY && offset > limit)
	139	goto out_sig;
	140	if (offset > inode->i_sb->s_maxbytes)
	141	goto out_big;
	142	} else {
	143	/*
	144	* truncation of in-use swapfiles is disallowed - it would
	145	* cause subsequent swapout to scribble on the now-freed
	146	* blocks.
	147	*/
	148	if (IS_SWAPFILE(inode))
	149	return -ETXTBSY;
	150	}
	151
	152	return 0;
	153	out_sig:
	154	send_sig(SIGXFSZ, current, 0);
	155	out_big:
	156	return -EFBIG;
	157	}
	158	EXPORT_SYMBOL(inode_newsize_ok);
	159
7bb46a67	160	/**
6a1a90ad	161	* setattr_copy - copy simple metadata updates into the generic inode
7bb46a67	162	* @inode: the inode to be updated
	163	* @attr: the new attributes
	164	*
6a1a90ad	165	* setattr_copy must be called with i_mutex held.
7bb46a67	166	*
6a1a90ad	167	* setattr_copy updates the inode's metadata with that specified
25985edc	168	* in attr. Noticeably missing is inode size update, which is more complex
2c27c65e	169	* as it requires pagecache updates.
7bb46a67	170	*
	171	* The inode is not marked as dirty after this operation. The rationale is
	172	* that for "simple" filesystems, the struct inode is the inode storage.
	173	* The caller is free to mark the inode dirty afterwards if needed.
	174	*/
6a1a90ad	175	void setattr_copy(struct inode inode, const struct iattr attr)
1da177e4 LT	176	{
1da177e4 LT	177	unsigned int ia_valid = attr->ia_valid;
4a30131e	178
1da177e4 LT	179	if (ia_valid & ATTR_UID)
	180	inode->i_uid = attr->ia_uid;
	181	if (ia_valid & ATTR_GID)
	182	inode->i_gid = attr->ia_gid;
	183	if (ia_valid & ATTR_ATIME)
	184	inode->i_atime = timespec_trunc(attr->ia_atime,
	185	inode->i_sb->s_time_gran);
	186	if (ia_valid & ATTR_MTIME)
	187	inode->i_mtime = timespec_trunc(attr->ia_mtime,
	188	inode->i_sb->s_time_gran);
	189	if (ia_valid & ATTR_CTIME)
	190	inode->i_ctime = timespec_trunc(attr->ia_ctime,
	191	inode->i_sb->s_time_gran);
	192	if (ia_valid & ATTR_MODE) {
	193	umode_t mode = attr->ia_mode;
	194
7fa294c8	195	if (!in_group_p(inode->i_gid) &&
23adbe12	196	!capable_wrt_inode_uidgid(inode, CAP_FSETID))
1da177e4 LT	197	mode &= ~S_ISGID;
	198	inode->i_mode = mode;
	199	}
7bb46a67	200	}
6a1a90ad	201	EXPORT_SYMBOL(setattr_copy);
7bb46a67	202
27ac0ffe BF	203	/**
	204	* notify_change - modify attributes of a filesytem object
	205	* @dentry: object affected
	206	* @iattr: new attributes
	207	* @delegated_inode: returns inode, if the inode is delegated
	208	*
	209	* The caller must hold the i_mutex on the affected object.
	210	*
	211	* If notify_change discovers a delegation in need of breaking,
	212	* it will return -EWOULDBLOCK and return a reference to the inode in
	213	* delegated_inode. The caller should then break the delegation and
	214	* retry. Because breaking a delegation may take a long time, the
	215	* caller should drop the i_mutex before doing so.
	216	*
	217	* Alternatively, a caller may pass NULL for delegated_inode. This may
	218	* be appropriate for callers that expect the underlying filesystem not
	219	* to be NFS exported. Also, passing NULL is fine for callers holding
	220	* the file open for write, as there can be no conflicting delegation in
	221	* that case.
	222	*/
	223	int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
1da177e4 LT	224	{
1da177e4 LT	225	struct inode *inode = dentry->d_inode;
8d334acd	226	umode_t mode = inode->i_mode;
1da177e4 LT	227	int error;
	228	struct timespec now;
	229	unsigned int ia_valid = attr->ia_valid;
	230
5955102c	231	WARN_ON_ONCE(!inode_is_locked(inode));
c4107b30	232
beb29e05 MS	233	if (ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID \| ATTR_TIMES_SET)) {
	234	if (IS_IMMUTABLE(inode) \|\| IS_APPEND(inode))
	235	return -EPERM;
	236	}
	237
f2b20f6e MS	238	/*
	239	* If utimes(2) and friends are called with times == NULL (or both
	240	* times are UTIME_NOW), then we need to check for write permission
	241	*/
	242	if (ia_valid & ATTR_TOUCH) {
	243	if (IS_IMMUTABLE(inode))
	244	return -EPERM;
	245
	246	if (!inode_owner_or_capable(inode)) {
	247	error = inode_permission(inode, MAY_WRITE);
	248	if (error)
	249	return error;
	250	}
	251	}
	252
69b45732	253	if ((ia_valid & ATTR_MODE)) {
8d334acd	254	umode_t amode = attr->ia_mode;
69b45732 AK	255	/* Flag setting protected by i_mutex */
	256	if (is_sxid(amode))
	257	inode->i_flags &= ~S_NOSEC;
	258	}
	259
c2050a45	260	now = current_time(inode);
1da177e4 LT	261
	262	attr->ia_ctime = now;
	263	if (!(ia_valid & ATTR_ATIME_SET))
	264	attr->ia_atime = now;
	265	if (!(ia_valid & ATTR_MTIME_SET))
	266	attr->ia_mtime = now;
b5376771	267	if (ia_valid & ATTR_KILL_PRIV) {
b5376771	268	error = security_inode_need_killpriv(dentry);
030b533c	269	if (error < 0)
b5376771	270	return error;
030b533c JK	271	if (error == 0)
030b533c JK	272	ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
b5376771	273	}
6de0ec00 JL	274
	275	/*
	276	* We now pass ATTR_KILL_S*ID to the lower level setattr function so
	277	* that the function has the ability to reinterpret a mode change
	278	* that's due to these bits. This adds an implicit restriction that
	279	* no function will ever call notify_change with both ATTR_MODE and
	280	* ATTR_KILL_S*ID set.
	281	*/
	282	if ((ia_valid & (ATTR_KILL_SUID\|ATTR_KILL_SGID)) &&
	283	(ia_valid & ATTR_MODE))
	284	BUG();
	285
1da177e4	286	if (ia_valid & ATTR_KILL_SUID) {
1da177e4	287	if (mode & S_ISUID) {
6de0ec00 JL	288	ia_valid = attr->ia_valid \|= ATTR_MODE;
6de0ec00 JL	289	attr->ia_mode = (inode->i_mode & ~S_ISUID);
1da177e4 LT	290	}
	291	}
	292	if (ia_valid & ATTR_KILL_SGID) {
1da177e4 LT	293	if ((mode & (S_ISGID \| S_IXGRP)) == (S_ISGID \| S_IXGRP)) {
	294	if (!(ia_valid & ATTR_MODE)) {
	295	ia_valid = attr->ia_valid \|= ATTR_MODE;
	296	attr->ia_mode = inode->i_mode;
	297	}
	298	attr->ia_mode &= ~S_ISGID;
	299	}
	300	}
6de0ec00	301	if (!(attr->ia_valid & ~(ATTR_KILL_SUID \| ATTR_KILL_SGID)))
1da177e4 LT	302	return 0;
1da177e4 LT	303
a475acf0 SF	304	/*
	305	* Verify that uid/gid changes are valid in the target
	306	* namespace of the superblock.
	307	*/
	308	if (ia_valid & ATTR_UID &&
	309	!kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid))
	310	return -EOVERFLOW;
	311	if (ia_valid & ATTR_GID &&
	312	!kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid))
	313	return -EOVERFLOW;
	314
0bd23d09 EB	315	/* Don't allow modifications of files with invalid uids or
	316	* gids unless those uids & gids are being made valid.
	317	*/
	318	if (!(ia_valid & ATTR_UID) && !uid_valid(inode->i_uid))
	319	return -EOVERFLOW;
	320	if (!(ia_valid & ATTR_GID) && !gid_valid(inode->i_gid))
	321	return -EOVERFLOW;
	322
a77b72da	323	error = security_inode_setattr(dentry, attr);
27ac0ffe BF	324	if (error)
	325	return error;
	326	error = try_break_deleg(inode, delegated_inode);
a77b72da MS	327	if (error)
	328	return error;
	329
eef2380c	330	if (inode->i_op->setattr)
a77b72da	331	error = inode->i_op->setattr(dentry, attr);
eef2380c CH	332	else
eef2380c CH	333	error = simple_setattr(dentry, attr);
1da177e4	334
975d2943	335	if (!error) {
0eeca283	336	fsnotify_change(dentry, ia_valid);
9957a504	337	ima_inode_post_setattr(dentry);
975d2943 MZ	338	evm_inode_post_setattr(dentry, ia_valid);
975d2943 MZ	339	}
0eeca283	340
1da177e4 LT	341	return error;
1da177e4 LT	342	}
1da177e4	343	EXPORT_SYMBOL(notify_change);