diff options
authorDarrick J. Wong <darrick.wong@oracle.com>2017-04-03 15:17:57 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-07 12:07:51 +0200
commitde417ea6b0a607e79b765838d397c0eb0bcb62d9 (patch)
parentc2ad2dc3d2648d603e7ab7dff4c6b38122206673 (diff)
xfs: fix over-copying of getbmap parameters from userspace
commit be6324c00c4d1e0e665f03ed1fc18863a88da119 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: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index a39197501a7c..73cfc7179124 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1542,10 +1542,11 @@ 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)