Commit 433f4ba1 authored by Paolo Bonzini's avatar Paolo Bonzini

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

The bounds check was present in KVM_GET_SUPPORTED_CPUID but not
KVM_GET_EMULATED_CPUID.

Reported-by: syzbot+e3f4897236c4eeb8af4f@syzkaller.appspotmail.com
Fixes: 84cffe49 ("kvm: Emulate MOVBE", 2013-10-29)
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3525d0cc
...@@ -504,7 +504,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, ...@@ -504,7 +504,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
r = -E2BIG; r = -E2BIG;
if (*nent >= maxnent) if (WARN_ON(*nent >= maxnent))
goto out; goto out;
do_host_cpuid(entry, function, 0); do_host_cpuid(entry, function, 0);
...@@ -815,6 +815,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, ...@@ -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, static int do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 func,
int *nent, int maxnent, unsigned int type) int *nent, int maxnent, unsigned int type)
{ {
if (*nent >= maxnent)
return -E2BIG;
if (type == KVM_GET_EMULATED_CPUID) if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_func_emulated(entry, func, nent, maxnent); return __do_cpuid_func_emulated(entry, func, nent, maxnent);
......
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