From: Avi Kivity <avi@redhat.com>
Date: Sun, 4 Oct 2009 14:45:13 +0000 (+0200)
Subject: KVM: Prevent overflow in KVM_GET_SUPPORTED_CPUID
X-Git-Tag: v2.6.32-rc4~55^2~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6a54435560efdab1a08f429a954df4d6c740bddf;p=platform%2Fkernel%2Flinux-stable.git

KVM: Prevent overflow in KVM_GET_SUPPORTED_CPUID

The number of entries is multiplied by the entry size, which can
overflow on 32-bit hosts.  Bound the entry count instead.

Reported-by: David Wagner <daw@cs.berkeley.edu>
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index be451ee..9b96953 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1591,6 +1591,8 @@ static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
 
 	if (cpuid->nent < 1)
 		goto out;
+	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
+		cpuid->nent = KVM_MAX_CPUID_ENTRIES;
 	r = -ENOMEM;
 	cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
 	if (!cpuid_entries)