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Commit cbdf35bc authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

vfs: export check_sticky() 



It's already duplicated in btrfs and about to be used in overlayfs too.

Move the sticky bit check to an inline helper and call the out-of-line
helper only in the unlikly case of the sticky bit being set.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent c771d683

fs/btrfs/ioctl.c

+1 −19
Original line number Diff line number Diff line
@@ -765,23 +765,6 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, 
	return ret;

}



/*  copy of check_sticky in fs/namei.c()

* It's inline, so penalty for filesystems that don't use sticky bit is

* minimal.

*/

static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)

{

	kuid_t fsuid = current_fsuid();



	if (!(dir->i_mode & S_ISVTX))

		return 0;

	if (uid_eq(inode->i_uid, fsuid))

		return 0;

	if (uid_eq(dir->i_uid, fsuid))

		return 0;

	return !capable(CAP_FOWNER);

}



/*  copy of may_delete in fs/namei.c()

 *	Check whether we can remove a link victim from directory dir, check

 *  whether the type of victim is right.
@@ -817,8 +800,7 @@ static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir) 
		return error;

	if (IS_APPEND(dir))

		return -EPERM;

	if (btrfs_check_sticky(dir, victim->d_inode)||

		IS_APPEND(victim->d_inode)||

	if (check_sticky(dir, victim->d_inode) || IS_APPEND(victim->d_inode) ||

	    IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))

		return -EPERM;

	if (isdir) {

fs/namei.c

+2 −7
Original line number Diff line number Diff line
@@ -2384,22 +2384,17 @@ kern_path_mountpoint(int dfd, const char *name, struct path *path, 
}

EXPORT_SYMBOL(kern_path_mountpoint);



/*

 * It's inline, so penalty for filesystems that don't use sticky bit is

 * minimal.

 */

static inline int check_sticky(struct inode *dir, struct inode *inode)

int __check_sticky(struct inode *dir, struct inode *inode)

{

	kuid_t fsuid = current_fsuid();



	if (!(dir->i_mode & S_ISVTX))

		return 0;

	if (uid_eq(inode->i_uid, fsuid))

		return 0;

	if (uid_eq(dir->i_uid, fsuid))

		return 0;

	return !capable_wrt_inode_uidgid(inode, CAP_FOWNER);

}

EXPORT_SYMBOL(__check_sticky);



/*

 *	Check whether we can remove a link victim from directory dir, check

include/linux/fs.h

+9 −0
Original line number Diff line number Diff line
@@ -2259,6 +2259,7 @@ extern int notify_change(struct dentry *, struct iattr *, struct inode **); 
extern int inode_permission(struct inode *, int);

extern int __inode_permission(struct inode *, int);

extern int generic_permission(struct inode *, int);

extern int __check_sticky(struct inode *dir, struct inode *inode);



static inline bool execute_ok(struct inode *inode)

{
@@ -2745,6 +2746,14 @@ static inline int is_sxid(umode_t mode) 
	return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));

}



static inline int check_sticky(struct inode *dir, struct inode *inode)

{

	if (!(dir->i_mode & S_ISVTX))

		return 0;



	return __check_sticky(dir, inode);

}



static inline void inode_has_no_xattr(struct inode *inode)

{

	if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))