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authorJuergen Gross <jgross@suse.com>2017-05-18 17:28:48 +0200
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2017-06-13 16:09:41 -0400
commit71df1d7ccad1c36f7321d6b3b48f2ea42681c363 (patch)
tree3a7679bd60a7d022a8fc9cf72491bb9173abac4e /drivers/block/xen-blkback
parent46464411307746e6297a034a9983a22c9dfc5a0c (diff)
xen/blkback: don't free be structure too early
The be structure must not be freed when freeing the blkif structure isn't done. Otherwise a use-after-free of be when unmapping the ring used for communicating with the frontend will occur in case of a late call of xenblk_disconnect() (e.g. due to an I/O still active when trying to disconnect). Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Steven Haigh <netwiz@crc.id.au> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/block/xen-blkback')
-rw-r--r--drivers/block/xen-blkback/xenbus.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 998915174bb8..4cdf0490983e 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -315,9 +315,10 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
static void xen_blkif_free(struct xen_blkif *blkif)
{
-
- xen_blkif_disconnect(blkif);
+ WARN_ON(xen_blkif_disconnect(blkif));
xen_vbd_free(&blkif->vbd);
+ kfree(blkif->be->mode);
+ kfree(blkif->be);
/* Make sure everything is drained before shutting down */
kmem_cache_free(xen_blkif_cachep, blkif);
@@ -514,8 +515,6 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
xen_blkif_put(be->blkif);
}
- kfree(be->mode);
- kfree(be);
return 0;
}