From: Simon Horman <horms@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>,
netdev@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"zdi-disclosures@trendmicro.com" <zdi-disclosures@trendmicro.com>,
Willy Tarreau <w@1wt.eu>
Subject: Re: [PATCH] xfrm: Fix xfrm state cache insertion race
Date: Mon, 15 Jun 2026 09:43:21 +0100 [thread overview]
Message-ID: <20260615084321.GE712698@horms.kernel.org> (raw)
In-Reply-To: <aiuSE5J-U8SuoZnk@gondor.apana.org.au>
On Fri, Jun 12, 2026 at 12:58:59PM +0800, Herbert Xu wrote:
> The xfrm input state cache insertion code checks the validity of
> the state before acquiring the global xfrm_state_lock. Thus it's
> possible for someone else to kill the state after it passed the
> validity check, and then the insertion will add the dead state
> to the cache.
>
> Fix this by moving the validity check inside the lock.
>
> This entire function is called on the input path, where BH must
> be off (e.g., the caller of this function xfrm_input acquires
> its spinlocks without disabling BH).
>
> So there is no need to disable BH here or take the RCU read lock.
> Remove both and replace them with an assertion that trips if BH
> is accidentally enabled on some future calling path.
>
> Fixes: 81a331a0e72d ("xfrm: Add an inbound percpu state cache.")
> Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Simon Horman <horms@kernel.org>
prev parent reply other threads:[~2026-06-15 8:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-12 4:58 [PATCH] xfrm: Fix xfrm state cache insertion race Herbert Xu
2026-06-15 8:43 ` Simon Horman [this message]
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