From ebee0eab08594b2bd5db716288a4f1ae5936e9bc Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 15 Feb 2021 08:52:27 +0100 Subject: Xen/gntdev: correct error checking in gntdev_map_grant_pages() Failure of the kernel part of the mapping operation should also be indicated as an error to the caller, or else it may assume the respective kernel VA is okay to access. Furthermore gnttab_map_refs() failing still requires recording successfully mapped handles, so they can be unmapped subsequently. This in turn requires there to be a way to tell full hypercall failure from partial success - preset map_op status fields such that they won't "happen" to look as if the operation succeeded. Also again use GNTST_okay instead of implying its value (zero). This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross --- drivers/xen/gntdev.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index aece224a4e70..5447c5156b2e 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -334,21 +334,22 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) pr_debug("map %d+%d\n", map->index, map->count); err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, map->pages, map->count); - if (err) - return err; for (i = 0; i < map->count; i++) { - if (map->map_ops[i].status) { + if (map->map_ops[i].status == GNTST_okay) + map->unmap_ops[i].handle = map->map_ops[i].handle; + else if (!err) err = -EINVAL; - continue; - } if (map->flags & GNTMAP_device_map) map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; - map->unmap_ops[i].handle = map->map_ops[i].handle; - if (use_ptemod) - map->kunmap_ops[i].handle = map->kmap_ops[i].handle; + if (use_ptemod) { + if (map->kmap_ops[i].status == GNTST_okay) + map->kunmap_ops[i].handle = map->kmap_ops[i].handle; + else if (!err) + err = -EINVAL; + } } return err; } -- cgit v1.2.3