[PATCH 4.4 52/53] xfs: in _attrlist_by_handle, copy the cursor back to userspace

Greg Kroah-Hartman
2017-06-05T17:22:23Z

From: Darrick J. Wong <darrick.wong@oracle.com>

commit 0facef7fb053be4353c0a48c2f48c9dbee91cb19 upstream.

When we're iterating inode xattrs by handle, we have to copy the
cursor back to userspace so that a subsequent invocation actually
retrieves subsequent contents.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/xfs/xfs_ioctl.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -403,6 +403,7 @@ xfs_attrlist_by_handle(
{
int error = -ENOMEM;
attrlist_cursor_kern_t *cursor;
+ struct xfs_fsop_attrlist_handlereq __user *p = arg;
xfs_fsop_attrlist_handlereq_t al_hreq;
struct dentry *dentry;
char *kbuf;
@@ -435,6 +436,11 @@ xfs_attrlist_by_handle(
if (error)
goto out_kfree;

+ if (copy_to_user(&p->pos, cursor, sizeof(attrlist_cursor_kern_t))) {
+ error = -EFAULT;
+ goto out_kfree;
+ }
+
if (copy_to_user(al_hreq.buffer, kbuf, al_hreq.buflen))
error = -EFAULT;