* [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug
@ 2020-05-13 13:26 Pan Nengyuan
2020-05-13 10:28 ` Igor Mammedov
2020-05-21 15:30 ` Paolo Bonzini
0 siblings, 2 replies; 3+ messages in thread
From: Pan Nengyuan @ 2020-05-13 13:26 UTC (permalink / raw)
To: pbonzini, rth, ehabkost, mtosatti
Cc: kvm, qemu-devel, zhang.zhanghailiang, euler.robot, Pan Nengyuan
When we hotplug vcpus, cpu_update_state is added to vm_change_state_head
in kvm_arch_init_vcpu(). But it forgot to delete in kvm_arch_destroy_vcpu() after
unplug. Then it will cause a use-after-free access. This patch delete it in
kvm_arch_destroy_vcpu() to fix that.
Reproducer:
virsh setvcpus vm1 4 --live
virsh setvcpus vm1 2 --live
virsh suspend vm1
virsh resume vm1
The UAF stack:
==qemu-system-x86_64==28233==ERROR: AddressSanitizer: heap-use-after-free on address 0x62e00002e798 at pc 0x5573c6917d9e bp 0x7fff07139e50 sp 0x7fff07139e40
WRITE of size 1 at 0x62e00002e798 thread T0
#0 0x5573c6917d9d in cpu_update_state /mnt/sdb/qemu/target/i386/kvm.c:742
#1 0x5573c699121a in vm_state_notify /mnt/sdb/qemu/vl.c:1290
#2 0x5573c636287e in vm_prepare_start /mnt/sdb/qemu/cpus.c:2144
#3 0x5573c6362927 in vm_start /mnt/sdb/qemu/cpus.c:2150
#4 0x5573c71e8304 in qmp_cont /mnt/sdb/qemu/monitor/qmp-cmds.c:173
#5 0x5573c727cb1e in qmp_marshal_cont qapi/qapi-commands-misc.c:835
#6 0x5573c7694c7a in do_qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:132
#7 0x5573c7694c7a in qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:175
#8 0x5573c71d9110 in monitor_qmp_dispatch /mnt/sdb/qemu/monitor/qmp.c:145
#9 0x5573c71dad4f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu/monitor/qmp.c:234
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
- v2: remove unnecessary set vmsentry to null(there is no non-null check).
---
target/i386/cpu.h | 1 +
target/i386/kvm.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index e818fc712a..afbd11b7a3 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1631,6 +1631,7 @@ struct X86CPU {
CPUNegativeOffsetState neg;
CPUX86State env;
+ VMChangeStateEntry *vmsentry;
uint64_t ucode_rev;
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 4901c6dd74..0a4eca5a85 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1770,7 +1770,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
}
- qemu_add_vm_change_state_handler(cpu_update_state, env);
+ cpu->vmsentry = qemu_add_vm_change_state_handler(cpu_update_state, env);
c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0);
if (c) {
@@ -1883,6 +1883,8 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
env->nested_state = NULL;
}
+ qemu_del_vm_change_state_handler(cpu->vmsentry);
+
return 0;
}
--
2.18.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug
2020-05-13 13:26 [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug Pan Nengyuan
@ 2020-05-13 10:28 ` Igor Mammedov
2020-05-21 15:30 ` Paolo Bonzini
1 sibling, 0 replies; 3+ messages in thread
From: Igor Mammedov @ 2020-05-13 10:28 UTC (permalink / raw)
To: Pan Nengyuan
Cc: pbonzini, rth, ehabkost, mtosatti, euler.robot, qemu-devel, kvm,
zhang.zhanghailiang
On Wed, 13 May 2020 09:26:30 -0400
Pan Nengyuan <pannengyuan@huawei.com> wrote:
> When we hotplug vcpus, cpu_update_state is added to vm_change_state_head
> in kvm_arch_init_vcpu(). But it forgot to delete in kvm_arch_destroy_vcpu() after
> unplug. Then it will cause a use-after-free access. This patch delete it in
> kvm_arch_destroy_vcpu() to fix that.
>
> Reproducer:
> virsh setvcpus vm1 4 --live
> virsh setvcpus vm1 2 --live
> virsh suspend vm1
> virsh resume vm1
>
> The UAF stack:
> ==qemu-system-x86_64==28233==ERROR: AddressSanitizer: heap-use-after-free on address 0x62e00002e798 at pc 0x5573c6917d9e bp 0x7fff07139e50 sp 0x7fff07139e40
> WRITE of size 1 at 0x62e00002e798 thread T0
> #0 0x5573c6917d9d in cpu_update_state /mnt/sdb/qemu/target/i386/kvm.c:742
> #1 0x5573c699121a in vm_state_notify /mnt/sdb/qemu/vl.c:1290
> #2 0x5573c636287e in vm_prepare_start /mnt/sdb/qemu/cpus.c:2144
> #3 0x5573c6362927 in vm_start /mnt/sdb/qemu/cpus.c:2150
> #4 0x5573c71e8304 in qmp_cont /mnt/sdb/qemu/monitor/qmp-cmds.c:173
> #5 0x5573c727cb1e in qmp_marshal_cont qapi/qapi-commands-misc.c:835
> #6 0x5573c7694c7a in do_qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:132
> #7 0x5573c7694c7a in qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:175
> #8 0x5573c71d9110 in monitor_qmp_dispatch /mnt/sdb/qemu/monitor/qmp.c:145
> #9 0x5573c71dad4f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu/monitor/qmp.c:234
>
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> ---
> - v2: remove unnecessary set vmsentry to null(there is no non-null check).
> ---
> target/i386/cpu.h | 1 +
> target/i386/kvm.c | 4 +++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index e818fc712a..afbd11b7a3 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1631,6 +1631,7 @@ struct X86CPU {
>
> CPUNegativeOffsetState neg;
> CPUX86State env;
> + VMChangeStateEntry *vmsentry;
>
> uint64_t ucode_rev;
>
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 4901c6dd74..0a4eca5a85 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1770,7 +1770,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
> }
> }
>
> - qemu_add_vm_change_state_handler(cpu_update_state, env);
> + cpu->vmsentry = qemu_add_vm_change_state_handler(cpu_update_state, env);
>
> c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0);
> if (c) {
> @@ -1883,6 +1883,8 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
> env->nested_state = NULL;
> }
>
> + qemu_del_vm_change_state_handler(cpu->vmsentry);
> +
> return 0;
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug
2020-05-13 13:26 [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug Pan Nengyuan
2020-05-13 10:28 ` Igor Mammedov
@ 2020-05-21 15:30 ` Paolo Bonzini
1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2020-05-21 15:30 UTC (permalink / raw)
To: Pan Nengyuan, rth, ehabkost, mtosatti
Cc: kvm, qemu-devel, zhang.zhanghailiang, euler.robot
On 13/05/20 15:26, Pan Nengyuan wrote:
> When we hotplug vcpus, cpu_update_state is added to vm_change_state_head
> in kvm_arch_init_vcpu(). But it forgot to delete in kvm_arch_destroy_vcpu() after
> unplug. Then it will cause a use-after-free access. This patch delete it in
> kvm_arch_destroy_vcpu() to fix that.
>
> Reproducer:
> virsh setvcpus vm1 4 --live
> virsh setvcpus vm1 2 --live
> virsh suspend vm1
> virsh resume vm1
>
> The UAF stack:
> ==qemu-system-x86_64==28233==ERROR: AddressSanitizer: heap-use-after-free on address 0x62e00002e798 at pc 0x5573c6917d9e bp 0x7fff07139e50 sp 0x7fff07139e40
> WRITE of size 1 at 0x62e00002e798 thread T0
> #0 0x5573c6917d9d in cpu_update_state /mnt/sdb/qemu/target/i386/kvm.c:742
> #1 0x5573c699121a in vm_state_notify /mnt/sdb/qemu/vl.c:1290
> #2 0x5573c636287e in vm_prepare_start /mnt/sdb/qemu/cpus.c:2144
> #3 0x5573c6362927 in vm_start /mnt/sdb/qemu/cpus.c:2150
> #4 0x5573c71e8304 in qmp_cont /mnt/sdb/qemu/monitor/qmp-cmds.c:173
> #5 0x5573c727cb1e in qmp_marshal_cont qapi/qapi-commands-misc.c:835
> #6 0x5573c7694c7a in do_qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:132
> #7 0x5573c7694c7a in qmp_dispatch /mnt/sdb/qemu/qapi/qmp-dispatch.c:175
> #8 0x5573c71d9110 in monitor_qmp_dispatch /mnt/sdb/qemu/monitor/qmp.c:145
> #9 0x5573c71dad4f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu/monitor/qmp.c:234
>
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
> - v2: remove unnecessary set vmsentry to null(there is no non-null check).
> ---
> target/i386/cpu.h | 1 +
> target/i386/kvm.c | 4 +++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index e818fc712a..afbd11b7a3 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1631,6 +1631,7 @@ struct X86CPU {
>
> CPUNegativeOffsetState neg;
> CPUX86State env;
> + VMChangeStateEntry *vmsentry;
>
> uint64_t ucode_rev;
>
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 4901c6dd74..0a4eca5a85 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1770,7 +1770,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
> }
> }
>
> - qemu_add_vm_change_state_handler(cpu_update_state, env);
> + cpu->vmsentry = qemu_add_vm_change_state_handler(cpu_update_state, env);
>
> c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0);
> if (c) {
> @@ -1883,6 +1883,8 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
> env->nested_state = NULL;
> }
>
> + qemu_del_vm_change_state_handler(cpu->vmsentry);
> +
> return 0;
> }
>
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-05-21 15:31 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-13 13:26 [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug Pan Nengyuan
2020-05-13 10:28 ` Igor Mammedov
2020-05-21 15:30 ` Paolo Bonzini
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).