From: Jason Wang <jasowang@redhat.com>
To: Anirudh Rayabharam <mail@anirudhrb.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com,
kvm <kvm@vger.kernel.org>,
virtualization <virtualization@lists.linux-foundation.org>,
netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] vhost: handle zero regions in vhost_set_memory
Date: Mon, 21 Feb 2022 15:56:29 +0800 [thread overview]
Message-ID: <CACGkMEs6HLM3ok29rm4u=Tq2preno_60Z6cvKw2T7=nak2yzkQ@mail.gmail.com> (raw)
In-Reply-To: <20220221072852.31820-1-mail@anirudhrb.com>
On Mon, Feb 21, 2022 at 3:45 PM Anirudh Rayabharam <mail@anirudhrb.com> wrote:
>
> Return early when userspace sends zero regions in the VHOST_SET_MEM_TABLE
> ioctl.
>
> Otherwise, this causes an erroneous entry to be added to the iotlb. This
> entry has a range size of 0 (due to u64 overflow). This then causes
> iotlb_access_ok() to loop indefinitely resulting in a hung thread.
> Syzbot has reported this here:
Interesting, I think iotlb_access_ok() won't be called for memory
table entries, or anything I missed?
(If this is not true, we need a kernel patch as well).
Thanks
>
> https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87
>
> Reported-and-tested-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com
> Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
> ---
> drivers/vhost/vhost.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 59edb5a1ffe2..821aba60eac2 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1428,6 +1428,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
> return -EFAULT;
> if (mem.padding)
> return -EOPNOTSUPP;
> + if (mem.nregions == 0)
> + return 0;
> if (mem.nregions > max_mem_regions)
> return -E2BIG;
> newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
> --
> 2.35.1
>
next prev parent reply other threads:[~2022-02-21 7:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-21 7:28 [PATCH] vhost: handle zero regions in vhost_set_memory Anirudh Rayabharam
2022-02-21 7:56 ` Jason Wang [this message]
2022-02-21 8:11 ` Anirudh Rayabharam
2022-02-21 16:48 ` Stefano Garzarella
2022-02-21 17:59 ` Anirudh Rayabharam
2022-02-21 19:57 ` Anirudh Rayabharam
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CACGkMEs6HLM3ok29rm4u=Tq2preno_60Z6cvKw2T7=nak2yzkQ@mail.gmail.com' \
--to=jasowang@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mail@anirudhrb.com \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).