Commit 1c862f5a authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Greg Kroah-Hartman

xfs: fix over-copying of getbmap parameters from userspace

commit be6324c0 upstream.

In xfs_ioc_getbmap, we should only copy the fields of struct getbmap
from userspace, or else we end up copying random stack contents into the
kernel.  struct getbmap is a strict subset of getbmapx, so a partial
structure copy should work fine.
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2cd6bd86
......@@ -1543,10 +1543,11 @@ xfs_ioc_getbmap(
unsigned int cmd,
void __user *arg)
{
struct getbmapx bmx;
struct getbmapx bmx = { 0 };
int error;
if (copy_from_user(&bmx, arg, sizeof(struct getbmapx)))
/* struct getbmap is a strict subset of struct getbmapx. */
if (copy_from_user(&bmx, arg, offsetof(struct getbmapx, bmv_iflags)))
return -EFAULT;
if (bmx.bmv_count < 2)
......
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