From: Paolo Bonzini <pbonzini@redhat.com>
To: "wangjie (P)" <wangjie88@huawei.com>,
Michal Privoznik <mprivozn@redhat.com>
Cc: zhangjixiang2@huawei.com, oscar.zhangbo@huawei.com,
qemu-devel@nongnu.org, qemu-block@nongnu.org,
"Fangyi \(C\)" <eric.fangyi@huawei.com>
Subject: Re: [Qemu-devel] question：about pr-helper unlink sock file fail
Date: Tue, 18 Jun 2019 19:34:20 +0200 [thread overview]
Message-ID: <2e914d2e-798f-311f-f189-8b4ca23fc270@redhat.com> (raw)
In-Reply-To: <7462792e-687f-b4b9-5242-5abccd318deb@huawei.com>
On 17/06/19 06:10, wangjie (P) wrote:
> Hi, I found there is a bug in pr-helper:
>
> We run pr-helper process in root, and drop all capabilities expect
> CAP_SYS_RAWIO.
>
> But the sock file which connect from qemu is owned by qemu group,
> when pr-helper exit,
>
> it will call “close_server_socket ->
> object_unref(OBJECT(server_ioc)) -> qio_channel_socket_finalize ->
> socket_listen_cleanup” ,
>
> unlink sock file will fail and output “Failed to unlink socket xxx,
> Permission denied”.
>
> I tried to add capability CAP_DAC_OVERRIDE in pr-helper, it will
> unlink sock success, but I think capability CAP_DAC_OVERRIDE is too
> dangerous.
Interesting... yeah, CAP_DAC_OVERRIDE is a big big hammer. I think this
would be fixed by also changing owner and group of the pr-helper to
qemu; it should work because it uses CAP_SYS_RAWIO.
Paolo
prev parent reply other threads:[~2019-06-18 17:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 4:10 [Qemu-devel] question：about pr-helper unlink sock file fail wangjie (P)
2019-06-18 17:34 ` Paolo Bonzini [this message]
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