KVM: Prevent overflow in KVM_GET_SUPPORTED_CPUID (CVE-2009-3638)
authorAvi Kivity <avi@redhat.com>
Sun, 4 Oct 2009 14:45:13 +0000 (16:45 +0200)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 10 Nov 2009 00:52:26 +0000 (16:52 -0800)
commit 6a54435560efdab1a08f429a954df4d6c740bddf upstream.

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>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
arch/x86/kvm/x86.c

index 60ebfd7..bf872f2 100644 (file)
@@ -1223,6 +1223,8 @@ 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)