From: Jan Beulich <jbeulich@suse.com>
Date: Tue, 14 May 2019 14:22:17 +0000 (+0200)
Subject: IOMMU: avoid NULL deref in iommu_lookup_page()
X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~2254
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=14e122fcc45d8a86e27be9663cbd7bcea1602b25;p=xen.git

IOMMU: avoid NULL deref in iommu_lookup_page()

Luckily the function currently has no callers - it would have called
through NULL for both Arm and x86/AMD.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
---

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index b453b32191..0d2dacf287 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -409,7 +409,7 @@ int iommu_lookup_page(struct domain *d, dfn_t dfn, mfn_t *mfn,
 {
     const struct domain_iommu *hd = dom_iommu(d);
 
-    if ( !iommu_enabled || !hd->platform_ops )
+    if ( !iommu_enabled || !hd->platform_ops || !hd->platform_ops->lookup_page )
         return -EOPNOTSUPP;
 
     return hd->platform_ops->lookup_page(d, dfn, mfn, flags);