From: David Marchand <david.marchand@redhat.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: dev@dpdk.org, chenbo.xia@intel.com, stable@dpdk.org
Subject: Re: [PATCH v2 1/2] vhost: fix possible FDs leak
Date: Mon, 30 Jan 2023 15:25:57 +0100 [thread overview]
Message-ID: <CAJFAV8yA458qMR5kAJbczVTOF2-LoqE+OtfUZw8etYrbpCK6qA@mail.gmail.com> (raw)
In-Reply-To: <abe31dd0-7f0a-f159-0996-01046dcafd21@redhat.com>
On Mon, Jan 30, 2023 at 10:46 AM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
>
>
> On 1/29/23 10:25, David Marchand wrote:
> > On Fri, Jan 27, 2023 at 5:55 PM Maxime Coquelin
> > <maxime.coquelin@redhat.com> wrote:
> >>
> >> On failure, read_vhost_message() only closed the message
> >> FDs if the header size was unexpected, but there are other
> >> cases where it is required. For exemple in the case the
> >> payload size read from the header is greater than the
> >> expected maximum payload size.
> >>
> >> This patch fixes this by closing all messages FDs in all
> >> error cases.
> >>
> >> Fixes: bf472259dde6 ("vhost: fix possible denial of service by leaking FDs")
> >> Cc: stable@dpdk.org
> >>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >
> > Reviewed-by: David Marchand <david.marchand@redhat.com>
> >
> > We mentionned offlist that the request type can be logged to help with debug.
> > Do you intend to add this as a follow up patch?
> >
> >
>
> Thinking about it, that's not that trivial because read_vhost_message()
> is called for both master and slave channels, so we would need to
> differentiate between both to print proper request name.
>
> It is doable by comparing the file descriptor passed as parameter with
> the slave one stored in struct virtio_net, but that's not super clean.
From the 3 different callers of read_vhost_message, I think the only
one that could gain from this debug is vhost_user_msg_handler().
And here, we could look at the message content on read_vhost_message return.
Like this untested and ugly snippet:
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 943058725e..1556f21a58 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2994,13 +2994,10 @@ vhost_user_msg_handler(int vid, int fd)
}
}
+ ctx.msg.request.master = VHOST_USER_NONE;
ret = read_vhost_message(dev, fd, &ctx);
- if (ret <= 0) {
- if (ret < 0)
- VHOST_LOG_CONFIG(dev->ifname, ERR, "vhost read
message failed\n");
- else
- VHOST_LOG_CONFIG(dev->ifname, INFO, "vhost
peer closed\n");
-
+ if (ret == 0) {
+ VHOST_LOG_CONFIG(dev->ifname, INFO, "vhost peer closed\n");
return -1;
}
@@ -3010,6 +3007,14 @@ vhost_user_msg_handler(int vid, int fd)
else
msg_handler = NULL;
+ if (ret < 0) {
+ VHOST_LOG_CONFIG(dev->ifname, ERR, "vhost read message
%s%s%sfailed\n",
+ msg_handler != NULL ? "for " : "",
+ msg_handler != NULL ? msg_handler->description : "",
+ msg_handler != NULL ? " " : "");
+ return -1;
+ }
+
if (msg_handler != NULL && msg_handler->description != NULL) {
if (request != VHOST_USER_IOTLB_MSG)
VHOST_LOG_CONFIG(dev->ifname, INFO,
--
David Marchand
next prev parent reply other threads:[~2023-01-30 14:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230127165540.37863-1-maxime.coquelin@redhat.com>
2023-01-27 16:55 ` Maxime Coquelin
2023-01-29 9:25 ` David Marchand
2023-01-30 9:46 ` Maxime Coquelin
2023-01-30 14:25 ` David Marchand [this message]
2023-02-07 16:18 ` Maxime Coquelin
2023-02-07 5:38 ` Xia, Chenbo
2023-01-27 16:55 ` [PATCH v2 2/2] vhost: fix possible FD leaks on MSG_TRUNC and MSG_CTRUNC Maxime Coquelin
2023-01-29 9:26 ` David Marchand
2023-01-27 16:55 ` [PATCH v2 2/2] vhost: fix possible FD leaks on truncation Maxime Coquelin
2023-02-07 5:38 ` Xia, Chenbo
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