From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: bp@alien8.de
Subject: [PATCH] KVM: x86: fix out-of-bounds write in KVM_GET_EMULATED_CPUID (CVE-2019-19332)
Date: Wed, 4 Dec 2019 12:20:12 +0100 [thread overview]
Message-ID: <1575458412-10241-1-git-send-email-pbonzini@redhat.com> (raw)
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>
---
arch/x86/kvm/cpuid.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 813a4d2e5c0c..cfafa320a8cf 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -504,7 +504,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
r = -E2BIG;
- if (*nent >= maxnent)
+ if (WARN_ON(*nent >= maxnent))
goto out;
do_host_cpuid(entry, function, 0);
@@ -815,6 +815,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
static int do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 func,
int *nent, int maxnent, unsigned int type)
{
+ if (*nent >= maxnent)
+ return -E2BIG;
+
if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_func_emulated(entry, func, nent, maxnent);
--
1.8.3.1
next reply other threads:[~2019-12-04 11:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-04 11:20 Paolo Bonzini [this message]
2019-12-18 12:24 ` [PATCH] KVM: x86: fix out-of-bounds write in KVM_GET_EMULATED_CPUID (CVE-2019-19332) Borislav Petkov
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