From: Jan Beulich jbeulich@suse.com
stable inclusion from linux-4.19.177 commit e07f06f6bbeed5bf47fed79ac6a57ec62b33304a CVE: CVE-2021-26932
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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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- drivers/xen/gntdev.c | 17 +++++++++-------- include/xen/grant_table.h | 1 + 2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 8a03087ecb26..a8b589b5f362 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -348,21 +348,22 @@ 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; } diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 9bc5bc07d4d3..a9978350b45b 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -157,6 +157,7 @@ gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr, map->flags = flags; map->ref = ref; map->dom = domid; + map->status = 1; /* arbitrary positive value */ }
static inline void