[linux.git] / fs / attr.c

/*
 *  linux/fs/attr.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  changes by Thomas Schoebel-Theuer
 */

#include <linux/module.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/capability.h>
#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/quotaops.h>
#include <linux/security.h>

/* Taken over from the old code... */

/* POSIX UID/GID verification for setting inode attributes. */
int inode_change_ok(struct inode *inode, struct iattr *attr)
{
	int retval = -EPERM;
	unsigned int ia_valid = attr->ia_valid;

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

	/* Make sure a caller can chown. */
	if ((ia_valid & ATTR_UID) &&
	    (current->fsuid != inode->i_uid ||
	     attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
		goto error;

	/* Make sure caller can chgrp. */
	if ((ia_valid & ATTR_GID) &&
	    (current->fsuid != inode->i_uid ||
	    (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
	    !capable(CAP_CHOWN))
		goto error;

	/* Make sure a caller can chmod. */
	if (ia_valid & ATTR_MODE) {
		if (!is_owner_or_cap(inode))
			goto error;
		/* Also check the setgid bit! */
		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
				inode->i_gid) && !capable(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 (!is_owner_or_cap(inode))
			goto error;
	}
fine:
	retval = 0;
error:
	return retval;
}

EXPORT_SYMBOL(inode_change_ok);

int inode_setattr(struct inode * inode, struct iattr * attr)
{
	unsigned int ia_valid = attr->ia_valid;

	if (ia_valid & ATTR_SIZE &&
	    attr->ia_size != i_size_read(inode)) {
		int error = vmtruncate(inode, attr->ia_size);
		if (error)
			return error;
	}

	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(CAP_FSETID))
			mode &= ~S_ISGID;
		inode->i_mode = mode;
	}
	mark_inode_dirty(inode);

	return 0;
}
EXPORT_SYMBOL(inode_setattr);

int notify_change(struct dentry * dentry, struct iattr * attr)
{
	struct inode *inode = dentry->d_inode;
	mode_t mode = inode->i_mode;
	int error;
	struct timespec now;
	unsigned int ia_valid = attr->ia_valid;

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

	now = current_fs_time(inode->i_sb);

	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) {
		attr->ia_valid &= ~ATTR_KILL_PRIV;
		ia_valid &= ~ATTR_KILL_PRIV;
		error = security_inode_need_killpriv(dentry);
		if (error > 0)
			error = security_inode_killpriv(dentry);
		if (error)
			return error;
	}

	/*
	 * 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;

	if (ia_valid & ATTR_SIZE)
		down_write(&dentry->d_inode->i_alloc_sem);

	if (inode->i_op && inode->i_op->setattr) {
		error = security_inode_setattr(dentry, attr);
		if (!error)
			error = inode->i_op->setattr(dentry, attr);
	} else {
		error = inode_change_ok(inode, attr);
		if (!error)
			error = security_inode_setattr(dentry, attr);
		if (!error) {
			if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
			    (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
				error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
			if (!error)
				error = inode_setattr(inode, attr);
		}
	}

	if (ia_valid & ATTR_SIZE)
		up_write(&dentry->d_inode->i_alloc_sem);

	if (!error)
		fsnotify_change(dentry, ia_valid);

	return error;
}

EXPORT_SYMBOL(notify_change);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/attr.c
	3	*
	4	* Copyright (C) 1991, 1992 Linus Torvalds
	5	* changes by Thomas Schoebel-Theuer
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/time.h>
	10	#include <linux/mm.h>
	11	#include <linux/string.h>
16f7e0fe	12	#include <linux/capability.h>
0eeca283	13	#include <linux/fsnotify.h>
1da177e4 LT	14	#include <linux/fcntl.h>
	15	#include <linux/quotaops.h>
	16	#include <linux/security.h>
1da177e4 LT	17
	18	/* Taken over from the old code... */
	19
	20	/* POSIX UID/GID verification for setting inode attributes. */
	21	int inode_change_ok(struct inode inode, struct iattr attr)
	22	{
	23	int retval = -EPERM;
	24	unsigned int ia_valid = attr->ia_valid;
	25
	26	/* If force is set do it anyway. */
	27	if (ia_valid & ATTR_FORCE)
	28	goto fine;
	29
	30	/* Make sure a caller can chown. */
	31	if ((ia_valid & ATTR_UID) &&
	32	(current->fsuid != inode->i_uid \|\|
	33	attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
	34	goto error;
	35
	36	/* Make sure caller can chgrp. */
	37	if ((ia_valid & ATTR_GID) &&
	38	(current->fsuid != inode->i_uid \|\|
	39	(!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
	40	!capable(CAP_CHOWN))
	41	goto error;
	42
	43	/* Make sure a caller can chmod. */
	44	if (ia_valid & ATTR_MODE) {
3bd858ab	45	if (!is_owner_or_cap(inode))
1da177e4 LT	46	goto error;
	47	/* Also check the setgid bit! */
	48	if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
	49	inode->i_gid) && !capable(CAP_FSETID))
	50	attr->ia_mode &= ~S_ISGID;
	51	}
	52
	53	/* Check for setting the inode time. */
9767d749	54	if (ia_valid & (ATTR_MTIME_SET \| ATTR_ATIME_SET \| ATTR_TIMES_SET)) {
3bd858ab	55	if (!is_owner_or_cap(inode))
1da177e4 LT	56	goto error;
	57	}
	58	fine:
	59	retval = 0;
	60	error:
	61	return retval;
	62	}
	63
	64	EXPORT_SYMBOL(inode_change_ok);
	65
	66	int inode_setattr(struct inode * inode, struct iattr * attr)
	67	{
	68	unsigned int ia_valid = attr->ia_valid;
4a30131e N	69
	70	if (ia_valid & ATTR_SIZE &&
	71	attr->ia_size != i_size_read(inode)) {
	72	int error = vmtruncate(inode, attr->ia_size);
	73	if (error)
	74	return error;
1da177e4 LT	75	}
	76
	77	if (ia_valid & ATTR_UID)
	78	inode->i_uid = attr->ia_uid;
	79	if (ia_valid & ATTR_GID)
	80	inode->i_gid = attr->ia_gid;
	81	if (ia_valid & ATTR_ATIME)
	82	inode->i_atime = timespec_trunc(attr->ia_atime,
	83	inode->i_sb->s_time_gran);
	84	if (ia_valid & ATTR_MTIME)
	85	inode->i_mtime = timespec_trunc(attr->ia_mtime,
	86	inode->i_sb->s_time_gran);
	87	if (ia_valid & ATTR_CTIME)
	88	inode->i_ctime = timespec_trunc(attr->ia_ctime,
	89	inode->i_sb->s_time_gran);
	90	if (ia_valid & ATTR_MODE) {
	91	umode_t mode = attr->ia_mode;
	92
	93	if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
	94	mode &= ~S_ISGID;
	95	inode->i_mode = mode;
	96	}
	97	mark_inode_dirty(inode);
4a30131e N	98
4a30131e N	99	return 0;
1da177e4	100	}
1da177e4 LT	101	EXPORT_SYMBOL(inode_setattr);
1da177e4 LT	102
1da177e4 LT	103	int notify_change(struct dentry * dentry, struct iattr * attr)
	104	{
	105	struct inode *inode = dentry->d_inode;
6de0ec00	106	mode_t mode = inode->i_mode;
1da177e4 LT	107	int error;
	108	struct timespec now;
	109	unsigned int ia_valid = attr->ia_valid;
	110
beb29e05 MS	111	if (ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID \| ATTR_TIMES_SET)) {
	112	if (IS_IMMUTABLE(inode) \|\| IS_APPEND(inode))
	113	return -EPERM;
	114	}
	115
1da177e4 LT	116	now = current_fs_time(inode->i_sb);
	117
	118	attr->ia_ctime = now;
	119	if (!(ia_valid & ATTR_ATIME_SET))
	120	attr->ia_atime = now;
	121	if (!(ia_valid & ATTR_MTIME_SET))
	122	attr->ia_mtime = now;
b5376771 SH	123	if (ia_valid & ATTR_KILL_PRIV) {
	124	attr->ia_valid &= ~ATTR_KILL_PRIV;
	125	ia_valid &= ~ATTR_KILL_PRIV;
	126	error = security_inode_need_killpriv(dentry);
	127	if (error > 0)
	128	error = security_inode_killpriv(dentry);
	129	if (error)
	130	return error;
	131	}
6de0ec00 JL	132
	133	/*
	134	* We now pass ATTR_KILL_S*ID to the lower level setattr function so
	135	* that the function has the ability to reinterpret a mode change
	136	* that's due to these bits. This adds an implicit restriction that
	137	* no function will ever call notify_change with both ATTR_MODE and
	138	* ATTR_KILL_S*ID set.
	139	*/
	140	if ((ia_valid & (ATTR_KILL_SUID\|ATTR_KILL_SGID)) &&
	141	(ia_valid & ATTR_MODE))
	142	BUG();
	143
1da177e4	144	if (ia_valid & ATTR_KILL_SUID) {
1da177e4	145	if (mode & S_ISUID) {
6de0ec00 JL	146	ia_valid = attr->ia_valid \|= ATTR_MODE;
6de0ec00 JL	147	attr->ia_mode = (inode->i_mode & ~S_ISUID);
1da177e4 LT	148	}
	149	}
	150	if (ia_valid & ATTR_KILL_SGID) {
1da177e4 LT	151	if ((mode & (S_ISGID \| S_IXGRP)) == (S_ISGID \| S_IXGRP)) {
	152	if (!(ia_valid & ATTR_MODE)) {
	153	ia_valid = attr->ia_valid \|= ATTR_MODE;
	154	attr->ia_mode = inode->i_mode;
	155	}
	156	attr->ia_mode &= ~S_ISGID;
	157	}
	158	}
6de0ec00	159	if (!(attr->ia_valid & ~(ATTR_KILL_SUID \| ATTR_KILL_SGID)))
1da177e4 LT	160	return 0;
	161
	162	if (ia_valid & ATTR_SIZE)
	163	down_write(&dentry->d_inode->i_alloc_sem);
	164
	165	if (inode->i_op && inode->i_op->setattr) {
	166	error = security_inode_setattr(dentry, attr);
	167	if (!error)
	168	error = inode->i_op->setattr(dentry, attr);
	169	} else {
	170	error = inode_change_ok(inode, attr);
	171	if (!error)
	172	error = security_inode_setattr(dentry, attr);
	173	if (!error) {
	174	if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) \|\|
	175	(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
	176	error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
	177	if (!error)
	178	error = inode_setattr(inode, attr);
	179	}
	180	}
	181
	182	if (ia_valid & ATTR_SIZE)
	183	up_write(&dentry->d_inode->i_alloc_sem);
	184
0eeca283 RL	185	if (!error)
	186	fsnotify_change(dentry, ia_valid);
	187
1da177e4 LT	188	return error;
	189	}
	190
	191	EXPORT_SYMBOL(notify_change);