Commit 16356ddb authored Mar 26, 2021 by Jan Beulich Committed by Greg Kroah-Hartman Mar 30, 2021

xen-blkback: don't leak persistent grants from xen_blkbk_map()



commit a846738f8c3788d846ed1f587270d2f2e3d32432 upstream.

The fix for XSA-365 zapped too many of the ->persistent_gnt[] entries.
Ones successfully obtained should not be overwritten, but instead left
for xen_blkbk_unmap_prepare() to pick up and put.

This is XSA-371.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent b707fabe

drivers/block/xen-blkback/blkback.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -944,7 +944,7 @@ static int xen_blkbk_map(struct xen_blkif_ring *ring,
		out:
		for (i = last_map; i < num; i++) {
		/* Don't zap current batch's valid persistent grants. */
		if(i >= last_map + segs_to_map)
		if(i >= map_until)
		pages[i]->persistent_gnt = NULL;
		pages[i]->handle = BLKBACK_INVALID_HANDLE;
		}