| Message ID | 1405052537-22431-1-git-send-email-wanpeng.li@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 11, 2014 at 12:22:17PM +0800, Wanpeng Li wrote: > This bug can be trigger by L1 goes down directly w/ enable_shadow_vmcs. > > [ 6413.158950] kvm: vmptrld (null)/780000000000 failed > [ 6413.158954] vmwrite error: reg 401e value 4 (err 1) > [ 6413.158957] CPU: 0 PID: 4840 Comm: qemu-system-x86 Tainted: G OE 3.16.0kvm+ #2 > [ 6413.158958] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A05 12/05/2013 > [ 6413.158959] 0000000000000003 ffff880210c9fb58 ffffffff81741de9 ffff8800d7433f80 > [ 6413.158960] ffff880210c9fb68 ffffffffa059fa08 ffff880210c9fb78 ffffffffa05938bf > [ 6413.158962] ffff880210c9fba8 ffffffffa059a97f ffff8800d7433f80 0000000000000003 > [ 6413.158963] Call Trace: > [ 6413.158968] [<ffffffff81741de9>] dump_stack+0x45/0x56 > [ 6413.158972] [<ffffffffa059fa08>] vmwrite_error+0x2c/0x2e [kvm_intel] > [ 6413.158974] [<ffffffffa05938bf>] vmcs_writel+0x1f/0x30 [kvm_intel] > [ 6413.158976] [<ffffffffa059a97f>] free_nested.part.73+0x5f/0x170 [kvm_intel] > [ 6413.158978] [<ffffffffa059ab13>] vmx_free_vcpu+0x33/0x70 [kvm_intel] > [ 6413.158991] [<ffffffffa0360324>] kvm_arch_vcpu_free+0x44/0x50 [kvm] > [ 6413.158998] [<ffffffffa0360f92>] kvm_arch_destroy_vm+0xf2/0x1f0 [kvm] > > Commit 26a865 (KVM: VMX: fix use after free of vmx->loaded_vmcs) fix the use > after free bug by move free_loaded_vmcs() before free_nested(), however, this > lead to free loaded_vmcs->vmcs premature and vmptrld load a NULL pointer during > sync shadow vmcs to vmcs12. In addition, vmwrite which used to disable shadow > vmcs and reset VMCS_LINK_POINTER failed since there is no valid current-VMCS. > This patch fix it by skipping kfree vmcs02_list item for current-vmcs in > nested_free_all_saved_vmcss() and kfree it after free_loaded_vmcs(). This can > also avoid use after free bug. > > Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> > --- > arch/x86/kvm/vmx.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 021d84a..6e427ac 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5762,10 +5762,11 @@ static void nested_free_all_saved_vmcss(struct vcpu_vmx *vmx) > { > struct vmcs02_list *item, *n; > list_for_each_entry_safe(item, n, &vmx->nested.vmcs02_pool, list) { > - if (vmx->loaded_vmcs != &item->vmcs02) > + if (vmx->loaded_vmcs != &item->vmcs02) { > free_loaded_vmcs(&item->vmcs02); > - list_del(&item->list); > - kfree(item); > + list_del(&item->list); > + kfree(item); > + } > } > vmx->nested.vmcs02_num = 0; > > @@ -7526,10 +7527,16 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) > static void vmx_free_vcpu(struct kvm_vcpu *vcpu) > { > struct vcpu_vmx *vmx = to_vmx(vcpu); > + struct vmcs02_list *item; > > free_vpid(vmx); > - free_loaded_vmcs(vmx->loaded_vmcs); > free_nested(vmx); static void free_nested(struct vcpu_vmx *vmx) { if (!vmx->nested.vmxon) return; vmx->nested.vmxon = false; > + free_loaded_vmcs(vmx->loaded_vmcs); > + if (vmx->nested.vmxon) Can this codepath ever execute? > + list_for_each_entry(item, &vmx->nested.vmcs02_pool, list) { > + list_del(&item->list); > + kfree(item); > + } -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Marcelo, On Fri, Jul 11, 2014 at 05:03:34PM -0300, Marcelo Tosatti wrote: >On Fri, Jul 11, 2014 at 12:22:17PM +0800, Wanpeng Li wrote: >> This bug can be trigger by L1 goes down directly w/ enable_shadow_vmcs. >> >> [ 6413.158950] kvm: vmptrld (null)/780000000000 failed >> [ 6413.158954] vmwrite error: reg 401e value 4 (err 1) >> [ 6413.158957] CPU: 0 PID: 4840 Comm: qemu-system-x86 Tainted: G OE 3.16.0kvm+ #2 >> [ 6413.158958] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A05 12/05/2013 >> [ 6413.158959] 0000000000000003 ffff880210c9fb58 ffffffff81741de9 ffff8800d7433f80 >> [ 6413.158960] ffff880210c9fb68 ffffffffa059fa08 ffff880210c9fb78 ffffffffa05938bf >> [ 6413.158962] ffff880210c9fba8 ffffffffa059a97f ffff8800d7433f80 0000000000000003 >> [ 6413.158963] Call Trace: >> [ 6413.158968] [<ffffffff81741de9>] dump_stack+0x45/0x56 >> [ 6413.158972] [<ffffffffa059fa08>] vmwrite_error+0x2c/0x2e [kvm_intel] >> [ 6413.158974] [<ffffffffa05938bf>] vmcs_writel+0x1f/0x30 [kvm_intel] >> [ 6413.158976] [<ffffffffa059a97f>] free_nested.part.73+0x5f/0x170 [kvm_intel] >> [ 6413.158978] [<ffffffffa059ab13>] vmx_free_vcpu+0x33/0x70 [kvm_intel] >> [ 6413.158991] [<ffffffffa0360324>] kvm_arch_vcpu_free+0x44/0x50 [kvm] >> [ 6413.158998] [<ffffffffa0360f92>] kvm_arch_destroy_vm+0xf2/0x1f0 [kvm] >> >> Commit 26a865 (KVM: VMX: fix use after free of vmx->loaded_vmcs) fix the use >> after free bug by move free_loaded_vmcs() before free_nested(), however, this >> lead to free loaded_vmcs->vmcs premature and vmptrld load a NULL pointer during >> sync shadow vmcs to vmcs12. In addition, vmwrite which used to disable shadow >> vmcs and reset VMCS_LINK_POINTER failed since there is no valid current-VMCS. >> This patch fix it by skipping kfree vmcs02_list item for current-vmcs in >> nested_free_all_saved_vmcss() and kfree it after free_loaded_vmcs(). This can >> also avoid use after free bug. >> >> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> >> --- >> arch/x86/kvm/vmx.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index 021d84a..6e427ac 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -5762,10 +5762,11 @@ static void nested_free_all_saved_vmcss(struct vcpu_vmx *vmx) >> { >> struct vmcs02_list *item, *n; >> list_for_each_entry_safe(item, n, &vmx->nested.vmcs02_pool, list) { >> - if (vmx->loaded_vmcs != &item->vmcs02) >> + if (vmx->loaded_vmcs != &item->vmcs02) { >> free_loaded_vmcs(&item->vmcs02); >> - list_del(&item->list); >> - kfree(item); >> + list_del(&item->list); >> + kfree(item); >> + } >> } >> vmx->nested.vmcs02_num = 0; >> >> @@ -7526,10 +7527,16 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) >> static void vmx_free_vcpu(struct kvm_vcpu *vcpu) >> { >> struct vcpu_vmx *vmx = to_vmx(vcpu); >> + struct vmcs02_list *item; >> >> free_vpid(vmx); >> - free_loaded_vmcs(vmx->loaded_vmcs); >> free_nested(vmx); > >static void free_nested(struct vcpu_vmx *vmx) >{ > if (!vmx->nested.vmxon) > return; > vmx->nested.vmxon = false; > >> + free_loaded_vmcs(vmx->loaded_vmcs); >> + if (vmx->nested.vmxon) > >Can this codepath ever execute? > How about set vmx->nested.vmcs02_num = 1 in nested_free_all_saved_vmcss() since the vmcs in vmcs02_pool which current used is not freed at this point and check vmx->nested.vmcs02_num == 1 in vmx_free_vcpu()? Otherwise, any better proposal is appreciated. Regards, Wanpeng Li >> + list_for_each_entry(item, &vmx->nested.vmcs02_pool, list) { >> + list_del(&item->list); >> + kfree(item); >> + } > >-- >To unsubscribe from this list: send the line "unsubscribe kvm" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 021d84a..6e427ac 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5762,10 +5762,11 @@ static void nested_free_all_saved_vmcss(struct vcpu_vmx *vmx) { struct vmcs02_list *item, *n; list_for_each_entry_safe(item, n, &vmx->nested.vmcs02_pool, list) { - if (vmx->loaded_vmcs != &item->vmcs02) + if (vmx->loaded_vmcs != &item->vmcs02) { free_loaded_vmcs(&item->vmcs02); - list_del(&item->list); - kfree(item); + list_del(&item->list); + kfree(item); + } } vmx->nested.vmcs02_num = 0; @@ -7526,10 +7527,16 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) static void vmx_free_vcpu(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); + struct vmcs02_list *item; free_vpid(vmx); - free_loaded_vmcs(vmx->loaded_vmcs); free_nested(vmx); + free_loaded_vmcs(vmx->loaded_vmcs); + if (vmx->nested.vmxon) + list_for_each_entry(item, &vmx->nested.vmcs02_pool, list) { + list_del(&item->list); + kfree(item); + } kfree(vmx->guest_msrs); kvm_vcpu_uninit(vcpu); kmem_cache_free(kvm_vcpu_cache, vmx);
This bug can be trigger by L1 goes down directly w/ enable_shadow_vmcs. [ 6413.158950] kvm: vmptrld (null)/780000000000 failed [ 6413.158954] vmwrite error: reg 401e value 4 (err 1) [ 6413.158957] CPU: 0 PID: 4840 Comm: qemu-system-x86 Tainted: G OE 3.16.0kvm+ #2 [ 6413.158958] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A05 12/05/2013 [ 6413.158959] 0000000000000003 ffff880210c9fb58 ffffffff81741de9 ffff8800d7433f80 [ 6413.158960] ffff880210c9fb68 ffffffffa059fa08 ffff880210c9fb78 ffffffffa05938bf [ 6413.158962] ffff880210c9fba8 ffffffffa059a97f ffff8800d7433f80 0000000000000003 [ 6413.158963] Call Trace: [ 6413.158968] [<ffffffff81741de9>] dump_stack+0x45/0x56 [ 6413.158972] [<ffffffffa059fa08>] vmwrite_error+0x2c/0x2e [kvm_intel] [ 6413.158974] [<ffffffffa05938bf>] vmcs_writel+0x1f/0x30 [kvm_intel] [ 6413.158976] [<ffffffffa059a97f>] free_nested.part.73+0x5f/0x170 [kvm_intel] [ 6413.158978] [<ffffffffa059ab13>] vmx_free_vcpu+0x33/0x70 [kvm_intel] [ 6413.158991] [<ffffffffa0360324>] kvm_arch_vcpu_free+0x44/0x50 [kvm] [ 6413.158998] [<ffffffffa0360f92>] kvm_arch_destroy_vm+0xf2/0x1f0 [kvm] Commit 26a865 (KVM: VMX: fix use after free of vmx->loaded_vmcs) fix the use after free bug by move free_loaded_vmcs() before free_nested(), however, this lead to free loaded_vmcs->vmcs premature and vmptrld load a NULL pointer during sync shadow vmcs to vmcs12. In addition, vmwrite which used to disable shadow vmcs and reset VMCS_LINK_POINTER failed since there is no valid current-VMCS. This patch fix it by skipping kfree vmcs02_list item for current-vmcs in nested_free_all_saved_vmcss() and kfree it after free_loaded_vmcs(). This can also avoid use after free bug. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> --- arch/x86/kvm/vmx.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)