[net-next-2.6.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(const 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);

/**
 * 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 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).
 *
 * inode_newsize_ok must be called with i_mutex held.
 */
int inode_newsize_ok(const struct inode *inode, loff_t offset)
{
	if (inode->i_size < offset) {
		unsigned long limit;

		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
		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);

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;

	error = security_inode_setattr(dentry, attr);
	if (error)
		return error;

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

	if (inode->i_op && inode->i_op->setattr) {
		error = inode->i_op->setattr(dentry, attr);
	} else {
		error = inode_change_ok(inode, 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 = vfs_dq_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. */
25d9e2d1	21	int inode_change_ok(const struct inode inode, struct iattr attr)
1da177e4 LT	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) &&
da9592ed	32	(current_fsuid() != inode->i_uid \|\|
1da177e4 LT	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) &&
da9592ed	38	(current_fsuid() != inode->i_uid \|\|
1da177e4 LT	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	}
1da177e4 LT	63	EXPORT_SYMBOL(inode_change_ok);
1da177e4 LT	64
25d9e2d1	65	/**
	66	* inode_newsize_ok - may this inode be truncated to a given size
	67	* @inode: the inode to be truncated
	68	* @offset: the new size to assign to the inode
	69	* @Returns: 0 on success, -ve errno on failure
	70	*
	71	* inode_newsize_ok will check filesystem limits and ulimits to check that the
	72	* new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
	73	* when necessary. Caller must not proceed with inode size change if failure is
	74	* returned. @inode must be a file (not directory), with appropriate
	75	* permissions to allow truncate (inode_newsize_ok does NOT check these
	76	* conditions).
	77	*
	78	* inode_newsize_ok must be called with i_mutex held.
	79	*/
	80	int inode_newsize_ok(const struct inode *inode, loff_t offset)
	81	{
	82	if (inode->i_size < offset) {
	83	unsigned long limit;
	84
	85	limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
	86	if (limit != RLIM_INFINITY && offset > limit)
	87	goto out_sig;
	88	if (offset > inode->i_sb->s_maxbytes)
	89	goto out_big;
	90	} else {
	91	/*
	92	* truncation of in-use swapfiles is disallowed - it would
	93	* cause subsequent swapout to scribble on the now-freed
	94	* blocks.
	95	*/
	96	if (IS_SWAPFILE(inode))
	97	return -ETXTBSY;
	98	}
	99
	100	return 0;
	101	out_sig:
	102	send_sig(SIGXFSZ, current, 0);
	103	out_big:
	104	return -EFBIG;
	105	}
	106	EXPORT_SYMBOL(inode_newsize_ok);
	107
1da177e4 LT	108	int inode_setattr(struct inode * inode, struct iattr * attr)
	109	{
	110	unsigned int ia_valid = attr->ia_valid;
4a30131e N	111
	112	if (ia_valid & ATTR_SIZE &&
	113	attr->ia_size != i_size_read(inode)) {
	114	int error = vmtruncate(inode, attr->ia_size);
	115	if (error)
	116	return error;
1da177e4 LT	117	}
	118
	119	if (ia_valid & ATTR_UID)
	120	inode->i_uid = attr->ia_uid;
	121	if (ia_valid & ATTR_GID)
	122	inode->i_gid = attr->ia_gid;
	123	if (ia_valid & ATTR_ATIME)
	124	inode->i_atime = timespec_trunc(attr->ia_atime,
	125	inode->i_sb->s_time_gran);
	126	if (ia_valid & ATTR_MTIME)
	127	inode->i_mtime = timespec_trunc(attr->ia_mtime,
	128	inode->i_sb->s_time_gran);
	129	if (ia_valid & ATTR_CTIME)
	130	inode->i_ctime = timespec_trunc(attr->ia_ctime,
	131	inode->i_sb->s_time_gran);
	132	if (ia_valid & ATTR_MODE) {
	133	umode_t mode = attr->ia_mode;
	134
	135	if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
	136	mode &= ~S_ISGID;
	137	inode->i_mode = mode;
	138	}
	139	mark_inode_dirty(inode);
4a30131e N	140
4a30131e N	141	return 0;
1da177e4	142	}
1da177e4 LT	143	EXPORT_SYMBOL(inode_setattr);
1da177e4 LT	144
1da177e4 LT	145	int notify_change(struct dentry * dentry, struct iattr * attr)
	146	{
	147	struct inode *inode = dentry->d_inode;
6de0ec00	148	mode_t mode = inode->i_mode;
1da177e4 LT	149	int error;
	150	struct timespec now;
	151	unsigned int ia_valid = attr->ia_valid;
	152
beb29e05 MS	153	if (ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID \| ATTR_TIMES_SET)) {
	154	if (IS_IMMUTABLE(inode) \|\| IS_APPEND(inode))
	155	return -EPERM;
	156	}
	157
1da177e4 LT	158	now = current_fs_time(inode->i_sb);
	159
	160	attr->ia_ctime = now;
	161	if (!(ia_valid & ATTR_ATIME_SET))
	162	attr->ia_atime = now;
	163	if (!(ia_valid & ATTR_MTIME_SET))
	164	attr->ia_mtime = now;
b5376771 SH	165	if (ia_valid & ATTR_KILL_PRIV) {
	166	attr->ia_valid &= ~ATTR_KILL_PRIV;
	167	ia_valid &= ~ATTR_KILL_PRIV;
	168	error = security_inode_need_killpriv(dentry);
	169	if (error > 0)
	170	error = security_inode_killpriv(dentry);
	171	if (error)
	172	return error;
	173	}
6de0ec00 JL	174
	175	/*
	176	* We now pass ATTR_KILL_S*ID to the lower level setattr function so
	177	* that the function has the ability to reinterpret a mode change
	178	* that's due to these bits. This adds an implicit restriction that
	179	* no function will ever call notify_change with both ATTR_MODE and
	180	* ATTR_KILL_S*ID set.
	181	*/
	182	if ((ia_valid & (ATTR_KILL_SUID\|ATTR_KILL_SGID)) &&
	183	(ia_valid & ATTR_MODE))
	184	BUG();
	185
1da177e4	186	if (ia_valid & ATTR_KILL_SUID) {
1da177e4	187	if (mode & S_ISUID) {
6de0ec00 JL	188	ia_valid = attr->ia_valid \|= ATTR_MODE;
6de0ec00 JL	189	attr->ia_mode = (inode->i_mode & ~S_ISUID);
1da177e4 LT	190	}
	191	}
	192	if (ia_valid & ATTR_KILL_SGID) {
1da177e4 LT	193	if ((mode & (S_ISGID \| S_IXGRP)) == (S_ISGID \| S_IXGRP)) {
	194	if (!(ia_valid & ATTR_MODE)) {
	195	ia_valid = attr->ia_valid \|= ATTR_MODE;
	196	attr->ia_mode = inode->i_mode;
	197	}
	198	attr->ia_mode &= ~S_ISGID;
	199	}
	200	}
6de0ec00	201	if (!(attr->ia_valid & ~(ATTR_KILL_SUID \| ATTR_KILL_SGID)))
1da177e4 LT	202	return 0;
1da177e4 LT	203
a77b72da MS	204	error = security_inode_setattr(dentry, attr);
	205	if (error)
	206	return error;
	207
1da177e4 LT	208	if (ia_valid & ATTR_SIZE)
	209	down_write(&dentry->d_inode->i_alloc_sem);
	210
	211	if (inode->i_op && inode->i_op->setattr) {
a77b72da	212	error = inode->i_op->setattr(dentry, attr);
1da177e4 LT	213	} else {
1da177e4 LT	214	error = inode_change_ok(inode, attr);
1da177e4 LT	215	if (!error) {
	216	if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) \|\|
	217	(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
9e3509e2 JK	218	error = vfs_dq_transfer(inode, attr) ?
9e3509e2 JK	219	-EDQUOT : 0;
1da177e4 LT	220	if (!error)
	221	error = inode_setattr(inode, attr);
	222	}
	223	}
	224
	225	if (ia_valid & ATTR_SIZE)
	226	up_write(&dentry->d_inode->i_alloc_sem);
	227
0eeca283 RL	228	if (!error)
	229	fsnotify_change(dentry, ia_valid);
	230
1da177e4 LT	231	return error;
	232	}
	233
	234	EXPORT_SYMBOL(notify_change);