Patch-mainline: v5.12-rc1
Git-commit: b512e1b077e5ccdbd6e225b15d934ab12453b70a
References: XSA-361 CVE-2021-26932 bsc#1181747
From: Jan Beulich <jbeulich@suse.com>
Date: Mon, 15 Feb 2021 08:50:08 +0100
Subject: [PATCH 2/9] Xen/x86: also check kernel mapping in
 set_foreign_p2m_mapping()

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

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 9affcf1d5bc2..30295d2ebd92 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -708,7 +708,8 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 		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) {
-- 
2.26.2