* [PATCH] kvm: fix page struct leak in handle_vmon @ 2017-01-24 10:56 Paolo Bonzini 2017-01-25 9:31 ` David Hildenbrand 2017-01-25 10:11 ` David Hildenbrand 0 siblings, 2 replies; 7+ messages in thread From: Paolo Bonzini @ 2017-01-24 10:56 UTC (permalink / raw) To: linux-kernel, kvm; +Cc: dvyukov handle_vmon gets a reference on VMXON region page, but does not release it. Release the reference. Found by syzkaller; based on a patch by Dmitry. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/vmx.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 42cc3d6f4d20..0f7345035210 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason, } page = nested_get_page(vcpu, vmptr); - if (page == NULL || - *(u32 *)kmap(page) != VMCS12_REVISION) { + if (page == NULL) { nested_vmx_failInvalid(vcpu); + return kvm_skip_emulated_instruction(vcpu); + } + if (*(u32 *)kmap(page) != VMCS12_REVISION) { kunmap(page); + nested_release_page_clean(page); + nested_vmx_failInvalid(vcpu); return kvm_skip_emulated_instruction(vcpu); } kunmap(page); + nested_release_page_clean(page); vmx->nested.vmxon_ptr = vmptr; break; case EXIT_REASON_VMCLEAR: -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-24 10:56 [PATCH] kvm: fix page struct leak in handle_vmon Paolo Bonzini @ 2017-01-25 9:31 ` David Hildenbrand 2017-01-25 9:52 ` Paolo Bonzini 2017-01-25 10:11 ` David Hildenbrand 1 sibling, 1 reply; 7+ messages in thread From: David Hildenbrand @ 2017-01-25 9:31 UTC (permalink / raw) To: Paolo Bonzini, linux-kernel, kvm; +Cc: dvyukov Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: > handle_vmon gets a reference on VMXON region page, > but does not release it. Release the reference. > > Found by syzkaller; based on a patch by Dmitry. > > Reported-by: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/vmx.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 42cc3d6f4d20..0f7345035210 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason, > } > > page = nested_get_page(vcpu, vmptr); > - if (page == NULL || > - *(u32 *)kmap(page) != VMCS12_REVISION) { > + if (page == NULL) { > nested_vmx_failInvalid(vcpu); > + return kvm_skip_emulated_instruction(vcpu); > + } > + if (*(u32 *)kmap(page) != VMCS12_REVISION) { shouldn't we also check if kmap even returned a valid pointer before dereferencing it? David thinks so. > kunmap(page); > + nested_release_page_clean(page); > + nested_vmx_failInvalid(vcpu); > return kvm_skip_emulated_instruction(vcpu); > } > kunmap(page); > + nested_release_page_clean(page); > vmx->nested.vmxon_ptr = vmptr; > break; > case EXIT_REASON_VMCLEAR: > -- David ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-25 9:31 ` David Hildenbrand @ 2017-01-25 9:52 ` Paolo Bonzini 2017-01-25 9:57 ` David Hildenbrand 0 siblings, 1 reply; 7+ messages in thread From: Paolo Bonzini @ 2017-01-25 9:52 UTC (permalink / raw) To: David Hildenbrand; +Cc: linux-kernel, kvm, dvyukov ----- Original Message ----- > From: "David Hildenbrand" <david@redhat.com> > To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org > Cc: dvyukov@google.com > Sent: Wednesday, January 25, 2017 10:31:13 AM > Subject: Re: [PATCH] kvm: fix page struct leak in handle_vmon > > Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: > > handle_vmon gets a reference on VMXON region page, > > but does not release it. Release the reference. > > > > Found by syzkaller; based on a patch by Dmitry. > > > > Reported-by: Dmitry Vyukov <dvyukov@google.com> > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > > --- > > arch/x86/kvm/vmx.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index 42cc3d6f4d20..0f7345035210 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu > > *vcpu, int exit_reason, > > } > > > > page = nested_get_page(vcpu, vmptr); > > - if (page == NULL || > > - *(u32 *)kmap(page) != VMCS12_REVISION) { > > + if (page == NULL) { > > nested_vmx_failInvalid(vcpu); > > + return kvm_skip_emulated_instruction(vcpu); > > + } > > + if (*(u32 *)kmap(page) != VMCS12_REVISION) { > > shouldn't we also check if kmap even returned a valid pointer before > dereferencing it? I don't think kmap can fail (page_address can)? Paolo > > kunmap(page); > > + nested_release_page_clean(page); > > + nested_vmx_failInvalid(vcpu); > > return kvm_skip_emulated_instruction(vcpu); > > } > > kunmap(page); > > + nested_release_page_clean(page); > > vmx->nested.vmxon_ptr = vmptr; > > break; > > case EXIT_REASON_VMCLEAR: > > > > -- > > David > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-25 9:52 ` Paolo Bonzini @ 2017-01-25 9:57 ` David Hildenbrand 2017-01-25 10:11 ` David Hildenbrand 0 siblings, 1 reply; 7+ messages in thread From: David Hildenbrand @ 2017-01-25 9:57 UTC (permalink / raw) To: Paolo Bonzini; +Cc: linux-kernel, kvm, dvyukov Am 25.01.2017 um 10:52 schrieb Paolo Bonzini: > > > ----- Original Message ----- >> From: "David Hildenbrand" <david@redhat.com> >> To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org >> Cc: dvyukov@google.com >> Sent: Wednesday, January 25, 2017 10:31:13 AM >> Subject: Re: [PATCH] kvm: fix page struct leak in handle_vmon >> >> Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: >>> handle_vmon gets a reference on VMXON region page, >>> but does not release it. Release the reference. >>> >>> Found by syzkaller; based on a patch by Dmitry. >>> >>> Reported-by: Dmitry Vyukov <dvyukov@google.com> >>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >>> --- >>> arch/x86/kvm/vmx.c | 9 +++++++-- >>> 1 file changed, 7 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index 42cc3d6f4d20..0f7345035210 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu >>> *vcpu, int exit_reason, >>> } >>> >>> page = nested_get_page(vcpu, vmptr); >>> - if (page == NULL || >>> - *(u32 *)kmap(page) != VMCS12_REVISION) { >>> + if (page == NULL) { >>> nested_vmx_failInvalid(vcpu); >>> + return kvm_skip_emulated_instruction(vcpu); >>> + } >>> + if (*(u32 *)kmap(page) != VMCS12_REVISION) { >> >> shouldn't we also check if kmap even returned a valid pointer before >> dereferencing it? > > I don't think kmap can fail (page_address can)? Then I wonder why there are some checks: e.g. nested_vmx_merge_msr_bitmap() msr_bitmap_l1 = (unsigned long *)kmap(page); if (!msr_bitmap_l1) { // no unmap ... return false; or vmx_complete_nested_posted_interrupt() vapic_page = kmap(vmx->nested.virtual_apic_page); if (!vapic_page) { // no unmap ... return -ENOMEM; But there is also no check in handle_vmptrld() for example. > > Paolo -- David ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-25 9:57 ` David Hildenbrand @ 2017-01-25 10:11 ` David Hildenbrand 2017-01-25 10:35 ` Paolo Bonzini 0 siblings, 1 reply; 7+ messages in thread From: David Hildenbrand @ 2017-01-25 10:11 UTC (permalink / raw) To: Paolo Bonzini; +Cc: linux-kernel, kvm, dvyukov Am 25.01.2017 um 10:57 schrieb David Hildenbrand: > Am 25.01.2017 um 10:52 schrieb Paolo Bonzini: >> >> >> ----- Original Message ----- >>> From: "David Hildenbrand" <david@redhat.com> >>> To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org >>> Cc: dvyukov@google.com >>> Sent: Wednesday, January 25, 2017 10:31:13 AM >>> Subject: Re: [PATCH] kvm: fix page struct leak in handle_vmon >>> >>> Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: >>>> handle_vmon gets a reference on VMXON region page, >>>> but does not release it. Release the reference. >>>> >>>> Found by syzkaller; based on a patch by Dmitry. >>>> >>>> Reported-by: Dmitry Vyukov <dvyukov@google.com> >>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >>>> --- >>>> arch/x86/kvm/vmx.c | 9 +++++++-- >>>> 1 file changed, 7 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>>> index 42cc3d6f4d20..0f7345035210 100644 >>>> --- a/arch/x86/kvm/vmx.c >>>> +++ b/arch/x86/kvm/vmx.c >>>> @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu >>>> *vcpu, int exit_reason, >>>> } >>>> >>>> page = nested_get_page(vcpu, vmptr); >>>> - if (page == NULL || >>>> - *(u32 *)kmap(page) != VMCS12_REVISION) { >>>> + if (page == NULL) { >>>> nested_vmx_failInvalid(vcpu); >>>> + return kvm_skip_emulated_instruction(vcpu); >>>> + } >>>> + if (*(u32 *)kmap(page) != VMCS12_REVISION) { >>> >>> shouldn't we also check if kmap even returned a valid pointer before >>> dereferencing it? >> >> I don't think kmap can fail (page_address can)? > > Then I wonder why there are some checks: > > e.g. nested_vmx_merge_msr_bitmap() > > msr_bitmap_l1 = (unsigned long *)kmap(page); > if (!msr_bitmap_l1) { > // no unmap > ... > return false; > > or vmx_complete_nested_posted_interrupt() > > vapic_page = kmap(vmx->nested.virtual_apic_page); > if (!vapic_page) { > // no unmap > ... > return -ENOMEM; > > > But there is also no check in handle_vmptrld() for example. > > >> >> Paolo > > Think you're right it can't fail. So something like that could most likely be done diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index a236dec..a9be221 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4973,10 +4973,6 @@ static int vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu) return 0; vapic_page = kmap(vmx->nested.virtual_apic_page); - if (!vapic_page) { - WARN_ON(1); - return -ENOMEM; - } __kvm_apic_update_irr(vmx->nested.pi_desc->pir, vapic_page); kunmap(vmx->nested.virtual_apic_page); @@ -9730,12 +9726,6 @@ static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu, return false; } msr_bitmap_l1 = (unsigned long *)kmap(page); - if (!msr_bitmap_l1) { - nested_release_page_clean(page); - WARN_ON(1); - return false; - } - memset(msr_bitmap_l0, 0xff, PAGE_SIZE); if (nested_cpu_has_virt_x2apic_mode(vmcs12)) { -- David ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-25 10:11 ` David Hildenbrand @ 2017-01-25 10:35 ` Paolo Bonzini 0 siblings, 0 replies; 7+ messages in thread From: Paolo Bonzini @ 2017-01-25 10:35 UTC (permalink / raw) To: David Hildenbrand; +Cc: linux-kernel, kvm, dvyukov On 25/01/2017 11:11, David Hildenbrand wrote: > Am 25.01.2017 um 10:57 schrieb David Hildenbrand: >> Am 25.01.2017 um 10:52 schrieb Paolo Bonzini: >>> >>> >>> ----- Original Message ----- >>>> From: "David Hildenbrand" <david@redhat.com> >>>> To: "Paolo Bonzini" <pbonzini@redhat.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org >>>> Cc: dvyukov@google.com >>>> Sent: Wednesday, January 25, 2017 10:31:13 AM >>>> Subject: Re: [PATCH] kvm: fix page struct leak in handle_vmon >>>> >>>> Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: >>>>> handle_vmon gets a reference on VMXON region page, >>>>> but does not release it. Release the reference. >>>>> >>>>> Found by syzkaller; based on a patch by Dmitry. >>>>> >>>>> Reported-by: Dmitry Vyukov <dvyukov@google.com> >>>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >>>>> --- >>>>> arch/x86/kvm/vmx.c | 9 +++++++-- >>>>> 1 file changed, 7 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>>>> index 42cc3d6f4d20..0f7345035210 100644 >>>>> --- a/arch/x86/kvm/vmx.c >>>>> +++ b/arch/x86/kvm/vmx.c >>>>> @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu >>>>> *vcpu, int exit_reason, >>>>> } >>>>> >>>>> page = nested_get_page(vcpu, vmptr); >>>>> - if (page == NULL || >>>>> - *(u32 *)kmap(page) != VMCS12_REVISION) { >>>>> + if (page == NULL) { >>>>> nested_vmx_failInvalid(vcpu); >>>>> + return kvm_skip_emulated_instruction(vcpu); >>>>> + } >>>>> + if (*(u32 *)kmap(page) != VMCS12_REVISION) { >>>> >>>> shouldn't we also check if kmap even returned a valid pointer before >>>> dereferencing it? >>> >>> I don't think kmap can fail (page_address can)? >> >> Then I wonder why there are some checks: >> >> e.g. nested_vmx_merge_msr_bitmap() >> >> msr_bitmap_l1 = (unsigned long *)kmap(page); >> if (!msr_bitmap_l1) { >> // no unmap >> ... >> return false; >> >> or vmx_complete_nested_posted_interrupt() >> >> vapic_page = kmap(vmx->nested.virtual_apic_page); >> if (!vapic_page) { >> // no unmap >> ... >> return -ENOMEM; >> >> >> But there is also no check in handle_vmptrld() for example. >> >> >>> >>> Paolo >> >> > > Think you're right it can't fail. > > So something like that could most likely be done > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index a236dec..a9be221 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -4973,10 +4973,6 @@ static int > vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu) > return 0; > > vapic_page = kmap(vmx->nested.virtual_apic_page); > - if (!vapic_page) { > - WARN_ON(1); > - return -ENOMEM; > - } > __kvm_apic_update_irr(vmx->nested.pi_desc->pir, vapic_page); > kunmap(vmx->nested.virtual_apic_page); > > @@ -9730,12 +9726,6 @@ static inline bool > nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu, > return false; > } > msr_bitmap_l1 = (unsigned long *)kmap(page); > - if (!msr_bitmap_l1) { > - nested_release_page_clean(page); > - WARN_ON(1); > - return false; > - } > - > memset(msr_bitmap_l0, 0xff, PAGE_SIZE); > > if (nested_cpu_has_virt_x2apic_mode(vmcs12)) { Yes, definitely. Want to send a patch? Paolo ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] kvm: fix page struct leak in handle_vmon 2017-01-24 10:56 [PATCH] kvm: fix page struct leak in handle_vmon Paolo Bonzini 2017-01-25 9:31 ` David Hildenbrand @ 2017-01-25 10:11 ` David Hildenbrand 1 sibling, 0 replies; 7+ messages in thread From: David Hildenbrand @ 2017-01-25 10:11 UTC (permalink / raw) To: Paolo Bonzini, linux-kernel, kvm; +Cc: dvyukov Am 24.01.2017 um 11:56 schrieb Paolo Bonzini: > handle_vmon gets a reference on VMXON region page, > but does not release it. Release the reference. > > Found by syzkaller; based on a patch by Dmitry. > > Reported-by: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/vmx.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 42cc3d6f4d20..0f7345035210 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -7085,13 +7085,18 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason, > } > > page = nested_get_page(vcpu, vmptr); > - if (page == NULL || > - *(u32 *)kmap(page) != VMCS12_REVISION) { > + if (page == NULL) { > nested_vmx_failInvalid(vcpu); > + return kvm_skip_emulated_instruction(vcpu); > + } > + if (*(u32 *)kmap(page) != VMCS12_REVISION) { > kunmap(page); > + nested_release_page_clean(page); > + nested_vmx_failInvalid(vcpu); > return kvm_skip_emulated_instruction(vcpu); > } > kunmap(page); > + nested_release_page_clean(page); > vmx->nested.vmxon_ptr = vmptr; > break; > case EXIT_REASON_VMCLEAR: > Reviewed-by: David Hildenbrand <david@redhat.com> -- David ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-01-25 10:35 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-01-24 10:56 [PATCH] kvm: fix page struct leak in handle_vmon Paolo Bonzini 2017-01-25 9:31 ` David Hildenbrand 2017-01-25 9:52 ` Paolo Bonzini 2017-01-25 9:57 ` David Hildenbrand 2017-01-25 10:11 ` David Hildenbrand 2017-01-25 10:35 ` Paolo Bonzini 2017-01-25 10:11 ` David Hildenbrand
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