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| author | Yu Zhang <yu.c.zhang@linux.intel.com> | 2017-09-18 18:45:01 +0800 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-09-19 14:28:58 +0200 |
| commit | d6500149bc4fddc5a91cd1a0c31b38fa36bff3ee (patch) | |
| tree | 63bebe3b669b051526b608e50db1fbdc4c753d94 /arch/x86/kvm/emulate.c | |
| parent | 95e2a3b3ef177730019e3799917193595133b275 (diff) | |
| download | linux-d6500149bc4fddc5a91cd1a0c31b38fa36bff3ee.tar.bz2 | |
KVM: x86: Fix the NULL pointer parameter in check_cr_write()
Routine check_cr_write() will trigger emulator_get_cpuid()->
kvm_cpuid() to get maxphyaddr, and NULL is passed as values
for ebx/ecx/edx. This is problematic because kvm_cpuid() will
dereference these pointers.
Fixes: d1cd3ce90044 ("KVM: MMU: check guest CR3 reserved bits based on its physical address width.")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 16bf6655aa85..15f527b44aa7 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4102,10 +4102,12 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt) ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); if (efer & EFER_LMA) { u64 maxphyaddr; - u32 eax = 0x80000008; + u32 eax, ebx, ecx, edx; - if (ctxt->ops->get_cpuid(ctxt, &eax, NULL, NULL, - NULL, false)) + eax = 0x80000008; + ecx = 0; + if (ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, + &edx, false)) maxphyaddr = eax & 0xff; else maxphyaddr = 36; |