Commit 244f6385 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

fuse: refresh stale attributes in fuse_permission() 



fuse_permission() didn't refresh inode attributes before using them, even if
the validity has already expired.

Thanks to Junjiro Okajima for spotting this.

Also remove some old code to unconditionally refresh the attributes on the
root inode.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 074406fa

fs/fuse/dir.c

+31 −30
Original line number Diff line number Diff line
@@ -663,7 +663,7 @@ static int fuse_link(struct dentry *entry, struct inode *newdir, 
	return err;

}



int fuse_do_getattr(struct inode *inode)

static int fuse_do_getattr(struct inode *inode)

{

	int err;

	struct fuse_attr_out arg;
@@ -723,30 +723,6 @@ static int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task) 
	return 0;

}



/*

 * Check whether the inode attributes are still valid

 *

 * If the attribute validity timeout has expired, then fetch the fresh

 * attributes with a 'getattr' request

 *

 * I'm not sure why cached attributes are never returned for the root

 * inode, this is probably being too cautious.

 */

static int fuse_revalidate(struct dentry *entry)

{

	struct inode *inode = entry->d_inode;

	struct fuse_inode *fi = get_fuse_inode(inode);

	struct fuse_conn *fc = get_fuse_conn(inode);



	if (!fuse_allow_task(fc, current))

		return -EACCES;

	if (get_node_id(inode) != FUSE_ROOT_ID &&

	    fi->i_time >= get_jiffies_64())

		return 0;



	return fuse_do_getattr(inode);

}



static int fuse_access(struct inode *inode, int mask)

{

	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -794,16 +770,33 @@ static int fuse_access(struct inode *inode, int mask) 
static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd)

{

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_inode *fi = get_fuse_inode(inode);

	bool refreshed = false;

	int err = 0;



	if (!fuse_allow_task(fc, current))

		return -EACCES;

	else if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {



	/*

	 * If attributes are needed, but are stale, refresh them

	 * before proceeding

	 */

	if (((fc->flags & FUSE_DEFAULT_PERMISSIONS) || (mask & MAY_EXEC)) &&

	    fi->i_time < get_jiffies_64()) {

		err = fuse_do_getattr(inode);

		if (err)

			return err;



		refreshed = true;

	}



	if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {

		int err = generic_permission(inode, mask, NULL);



		/* If permission is denied, try to refresh file

		   attributes.  This is also needed, because the root

		   node will at first have no permissions */

		if (err == -EACCES) {

		if (err == -EACCES && !refreshed) {

		 	err = fuse_do_getattr(inode);

			if (!err)

				err = generic_permission(inode, mask, NULL);
@@ -814,7 +807,6 @@ static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd) 
		   noticed immediately, only after the attribute

		   timeout has expired */



		return err;

	} else {

		int mode = inode->i_mode;

		if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO))
@@ -822,8 +814,8 @@ static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd) 


		if (nd && (nd->flags & (LOOKUP_ACCESS | LOOKUP_CHDIR)))

			return fuse_access(inode, mask);

		return 0;

	}

	return err;

}



static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
@@ -1052,7 +1044,16 @@ static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry, 
			struct kstat *stat)

{

	struct inode *inode = entry->d_inode;

	int err = fuse_revalidate(entry);

	struct fuse_inode *fi = get_fuse_inode(inode);

	struct fuse_conn *fc = get_fuse_conn(inode);

	int err = 0;



	if (!fuse_allow_task(fc, current))

		return -EACCES;



	if (fi->i_time < get_jiffies_64())

		err = fuse_do_getattr(inode);



	if (!err)

		generic_fillattr(inode, stat);

fs/fuse/file.c

+0 −8
Original line number Diff line number Diff line
@@ -106,14 +106,6 @@ int fuse_open_common(struct inode *inode, struct file *file, int isdir) 
	if (err)

		return err;



	/* If opening the root node, no lookup has been performed on

	   it, so the attributes must be refreshed */

	if (get_node_id(inode) == FUSE_ROOT_ID) {

		err = fuse_do_getattr(inode);

		if (err)

		 	return err;

	}



	ff = fuse_file_alloc();

	if (!ff)

		return -ENOMEM;

fs/fuse/fuse_i.h

+0 −5
Original line number Diff line number Diff line
@@ -532,11 +532,6 @@ void request_send_background(struct fuse_conn *fc, struct fuse_req *req); 
/* Abort all requests */

void fuse_abort_conn(struct fuse_conn *fc);



/**

 * Get the attributes of a file

 */

int fuse_do_getattr(struct inode *inode);



/**

 * Invalidate inode attributes

 */

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