linux-kernel - [RFC v2 01/12] KVM: arm/arm64: Set dist->spis to NULL after kfree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 27 Mar 2018 16:04:05 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu, marc.zyngier@....com,
        cdall@...nel.org, peter.maydell@...aro.org
Cc:     andre.przywara@....com, drjones@...hat.com, wei@...hat.com
Subject: [RFC v2 01/12] KVM: arm/arm64: Set dist->spis to NULL after kfree

in case kvm_vgic_map_resources() fails, typically if the vgic
distributor is not defined, __kvm_vgic_destroy will be called
several times. Indeed kvm_vgic_map_resources() is called on
first vcpu run. As a result dist->spis is freeed more than once
and on the second time it causes a "kernel BUG at mm/slub.c:3912!"

Set dist->spis to NULL to avoid the crash.

Signed-off-by: Eric Auger <eric.auger@...hat.com>
---
 virt/kvm/arm/vgic/vgic-init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 743ca5c..3349f2b 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -325,6 +325,7 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
 	dist->initialized = false;
 
 	kfree(dist->spis);
+	dist->spis = NULL;
 	dist->nr_spis = 0;
 
 	if (vgic_supports_direct_msis(kvm))
-- 
2.5.5