From: Pan Nengyuan <pannengyuan@huawei.com>
To: <pbonzini@redhat.com>, <rth@twiddle.net>, <ehabkost@redhat.com>,
<mtosatti@redhat.com>
Cc: <kvm@vger.kernel.org>, <qemu-devel@nongnu.org>,
<zhang.zhanghailiang@huawei.com>, <euler.robot@huawei.com>,
Pan Nengyuan <pannengyuan@huawei.com>
Subject: [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug
Date: Wed, 13 May 2020 09:26:30 -0400 [thread overview]
Message-ID: <20200513132630.13412-1-pannengyuan@huawei.com> (raw)
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
next reply other threads:[~2020-05-13 7:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 13:26 Pan Nengyuan [this message]
2020-05-13 10:28 ` [PATCH v2] i386/kvm: fix a use-after-free when vcpu plug/unplug Igor Mammedov
2020-05-21 15:30 ` Paolo Bonzini
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