[PATCH 4.4 26/35] Xen/x86: also check kernel mapping in set_foreign_p2m_mapping()

Greg Kroah-Hartman
2021-02-22T13:46:38Z

From: Jan Beulich <jbeulich@suse.com>

commit b512e1b077e5ccdbd6e225b15d934ab12453b70a upstream.

We should not set up further state if either mapping failed; paying
attention to just the user mapping's status isn't enough.

Also 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>

---
arch/x86/xen/p2m.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -725,7 +725,8 @@ int set_foreign_p2m_mapping(struct gntta
unsigned long mfn, pfn;

/* Do not add to override if the map failed. */
- if (map_ops[i].status)
+ if (map_ops[i].status != GNTST_okay ||
+ (kmap_ops && kmap_ops[i].status != GNTST_okay))
continue;

if (map_ops[i].flags & GNTMAP_contains_pte) {