linux-kernel - [ 134/143] KVM: Improve create VCPU parameter (CVE-2013-4587)

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]

Message-Id: <20140512003206.271246826@1wt.eu>
Date:	Mon, 12 May 2014 02:34:14 +0200
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Andrew Honig <ahonig@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>, Willy Tarreau <w@....eu>
Subject: [ 134/143] KVM: Improve create VCPU parameter (CVE-2013-4587)

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Andy Honig <ahonig@...gle.com>

commit 338c7dbadd2671189cec7faf64c84d01071b3f96 upstream

In multiple functions the vcpu_id is used as an offset into a bitfield.  Ag
malicious user could specify a vcpu_id greater than 255 in order to set or
clear bits in kernel memory.  This could be used to elevate priveges in the
kernel.  This patch verifies that the vcpu_id provided is less than 255.
The api documentation already specifies that the vcpu_id must be less than
max_vcpus, but this is currently not checked.

Reported-by: Andrew Honig <ahonig@...gle.com>
Cc: stable@...r.kernel.org
Signed-off-by: Andrew Honig <ahonig@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Willy Tarreau <w@....eu>
---
 virt/kvm/kvm_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 82b6fdc..3b9443b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1846,6 +1846,9 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 	int r;
 	struct kvm_vcpu *vcpu, *v;
 
+	if (id >= KVM_MAX_VCPUS)
+		return -EINVAL;
+
 	vcpu = kvm_arch_vcpu_create(kvm, id);
 	if (IS_ERR(vcpu))
 		return PTR_ERR(vcpu);
-- 
1.7.12.2.21.g234cd45.dirty



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/