linux-kernel - Re: CVE-2021-47581: xen/netback: don't queue unlimited number of packages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date: Thu, 20 Jun 2024 09:57:20 +0200
From: Juergen Gross <jgross@...e.com>
To: cve@...nel.org, linux-kernel@...r.kernel.org,
 linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: CVE-2021-47581: xen/netback: don't queue unlimited number of
 packages

On 19.06.24 16:54, Greg Kroah-Hartman wrote:
> Description
> ===========
> 
> In the Linux kernel, the following vulnerability has been resolved:
> 
> xen/netback: don't queue unlimited number of packages
> 
> In case a guest isn't consuming incoming network traffic as fast as it
> is coming in, xen-netback is buffering network packages in unlimited
> numbers today. This can result in host OOM situations.
> 
> Commit f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal
> queue and carrier flapping") meant to introduce a mechanism to limit
> the amount of buffered data by stopping the Tx queue when reaching the
> data limit, but this doesn't work for cases like UDP.
> 
> When hitting the limit don't queue further SKBs, but drop them instead.
> In order to be able to tell Rx packages have been dropped increment the
> rx_dropped statistics counter in this case.
> 
> It should be noted that the old solution to continue queueing SKBs had
> the additional problem of an overflow of the 32-bit rx_queue_len value
> would result in intermittent Tx queue enabling.
> 
> This is part of XSA-392
> 
> The Linux kernel CVE team has assigned CVE-2021-47581 to this issue.

When issuing XSA-392 the Xen security team already assigned CVE-2021-28715
to this issue.


Juergen

Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3684 bytes)

Download attachment "OpenPGP_signature.asc" of type "application/pgp-signature" (496 bytes)