From: Jan Beulich jbeulich@suse.com
commit ebee0eab08594b2bd5db716288a4f1ae5936e9bc upstream.
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 jbeulich@suse.com Cc: stable@vger.kernel.org Reviewed-by: Juergen Gross jgross@suse.com Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/xen/gntdev.c | 17 +++++++++-------- include/xen/grant_table.h | 1 + 2 files changed, 10 insertions(+), 8 deletions(-)
--- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -318,21 +318,22 @@ static int map_grant_pages(struct grant_ 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; } --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -157,6 +157,7 @@ gnttab_set_map_op(struct gnttab_map_gran map->flags = flags; map->ref = ref; map->dom = domid; + map->status = 1; /* arbitrary positive value */ }
static inline void