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authorPaolo Bonzini <pbonzini@redhat.com>2019-12-04 10:28:54 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-12-17 20:38:58 +0100
commitf70609f898d63973388b36adf3650489311b13b9 (patch)
treeb312c9eca7298032eb0d6b66bf87bca62eb34010
parentd9792606b604b972afebc89375e1ffad763135ac (diff)
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>
-rw-r--r--arch/x86/kvm/cpuid.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 33f87b696487..38959b173a42 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -404,7 +404,7 @@ 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);
@@ -707,6 +707,9 @@ 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);