linux-kernel - Re: [PATCH net] net/xfrm: Refuse to allocate xfrm

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>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aND13piG0NIlBt1U@secunet.com>
Date: Mon, 22 Sep 2025 09:08:14 +0200
From: Steffen Klassert <steffen.klassert@...unet.com>
To: "Nikola Z. Ivanov" <zlatistiv@...il.com>
CC: <herbert@...dor.apana.org.au>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<horms@...nel.org>, <saakashkumar@...vell.com>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-kernel-mentees@...ts.linux.dev>
Subject: Re: [PATCH net] net/xfrm: Refuse to allocate xfrm_state with SPI
 value 0

On Sun, Sep 21, 2025 at 05:27:01AM +0300, Nikola Z. Ivanov wrote:
> Reported by syzkaller: "KASAN: slab-use-after-free Read in xfrm_alloc_spi"
> 
> Before commit 94f39804d891 ("xfrm: Duplicate SPI Handling")
> xfrm_alloc_spi would report spi=0 as unavailable.
> Add this behaviour back by adding 1 to the "low" value when it is passed as 0.
> Allocating xfrm_state with spi=0 leads to UAF or CPU stall.
> 
> Fixes: 94f39804d891 ("xfrm: Duplicate SPI Handling")
> Signed-off-by: Nikola Z. Ivanov <zlatistiv@...il.com>

This is already fixed in the ipsec tree by

commit cd8ae32e4e46 ("xfrm: xfrm_alloc_spi shouldn't use 0 as SPI")

Thanks a lot anyway!