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| author | Wanpeng Li <wanpengli@tencent.com> | 2021-02-26 15:59:59 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-02-26 03:16:50 -0500 |
| commit | 919f4ebc598701670e80e31573a58f1f2d2bf918 (patch) | |
| tree | 37723508bc564318907858057ed402ba510f9ac8 /arch/x86 | |
| parent | ffe76c24c5c1851e5ef949d8726d57e78cd0cf34 (diff) | |
| download | linux-919f4ebc598701670e80e31573a58f1f2d2bf918.tar.bz2 | |
KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref
Reported by syzkaller:
KASAN: null-ptr-deref in range [0x0000000000000140-0x0000000000000147]
CPU: 1 PID: 8370 Comm: syz-executor859 Not tainted 5.11.0-syzkaller #0
RIP: 0010:synic_get arch/x86/kvm/hyperv.c:165 [inline]
RIP: 0010:kvm_hv_set_sint_gsi arch/x86/kvm/hyperv.c:475 [inline]
RIP: 0010:kvm_hv_irq_routing_update+0x230/0x460 arch/x86/kvm/hyperv.c:498
Call Trace:
kvm_set_irq_routing+0x69b/0x940 arch/x86/kvm/../../../virt/kvm/irqchip.c:223
kvm_vm_ioctl+0x12d0/0x2800 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3959
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
Hyper-V context is lazily allocated until Hyper-V specific MSRs are accessed
or SynIC is enabled. However, the syzkaller testcase sets irq routing table
directly w/o enabling SynIC. This results in null-ptr-deref when accessing
SynIC Hyper-V context. This patch fixes it.
syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=163342ccd00000
Reported-by: syzbot+6987f3b2dbd9eda95f12@syzkaller.appspotmail.com
Fixes: 8f014550dfb1 ("KVM: x86: hyper-v: Make Hyper-V emulation enablement conditional")
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1614326399-5762-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 7d2dae92d638..58fa8c029867 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -159,7 +159,7 @@ static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vpidx) struct kvm_vcpu_hv_synic *synic; vcpu = get_vcpu_by_vpidx(kvm, vpidx); - if (!vcpu) + if (!vcpu || !to_hv_vcpu(vcpu)) return NULL; synic = to_hv_synic(vcpu); return (synic->active) ? synic : NULL; |