KVM: x86: fix out-of-bounds write in KVM_GET_EMULATED_CPUID (CVE-2019-19332)

commit 433f4ba1904100da65a311033f17a9bf586b287e upstream.

The bounds check was present in KVM_GET_SUPPORTED_CPUID but not
KVM_GET_EMULATED_CPUID.

Reported-by: syzbot+e3f4897236c4eeb8af4f@syzkaller.appspotmail.com
Fixes: 84cffe499b94 ("kvm: Emulate MOVBE", 2013-10-29)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paolo Bonzini 2019-12-04 10:28:54 +01:00 committed by Greg Kroah-Hartman
parent 0af17b8b93
commit 385bddaf5e

View File

@ -373,7 +373,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
r = -E2BIG;
if (*nent >= maxnent)
if (WARN_ON(*nent >= maxnent))
goto out;
do_cpuid_1_ent(entry, function, index);
@ -669,6 +669,9 @@ out:
static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
u32 idx, int *nent, int maxnent, unsigned int type)
{
if (*nent >= maxnent)
return -E2BIG;
if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);