From: Simon Horman <horms@kernel.org>
To: Lee Jones <lee@kernel.org>
Cc: Jon Maloy <jmaloy@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Ying Xue <ying.xue@windriver.com>,
netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net,
linux-kernel@vger.kernel.org,
Tung Nguyen <tung.quang.nguyen@est.tech>
Subject: Re: [PATCH v2 1/1] tipc: fix double-free in tipc_buf_append()
Date: Thu, 23 Apr 2026 20:10:25 +0100 [thread overview]
Message-ID: <20260423191025.GJ900403@horms.kernel.org> (raw)
In-Reply-To: <20260421124528.162996-1-lee@kernel.org>
On Tue, Apr 21, 2026 at 01:45:26PM +0100, Lee Jones wrote:
> tipc_msg_validate() can potentially reallocate the skb it is validating,
> freeing the old one. In tipc_buf_append(), it was being called with a
> pointer to a local variable which was a copy of the caller's skb
> pointer.
>
> If the skb was reallocated and validation subsequently failed, the error
> handling path would free the original skb pointer, which had already
> been freed, leading to double-free.
>
> Fix this by checking if head now points to a newly allocated reassembled
> skb. If it does, reassign *headbuf for later freeing operations.
>
> Fixes: d618d09a68e4 ("tipc: enforce valid ratio between skb truesize and contents")
> Suggested-by: Tung Nguyen <tung.quang.nguyen@est.tech>
> Signed-off-by: Lee Jones <lee@kernel.org>
> ---
> 1v => v2: Keep the passed pointer type the same, but reassign on-change
FTR: Sashiko has generated a review of this patch which I have examined.
I do not believe that review should halt progress of this patch
as it appears that the problem flagged pre-dates this patch. Actually,
its unclear to me if it is a problem that warrants addressing at all.
But I'd appreciate if it could be looked over as a follow-up task.
prev parent reply other threads:[~2026-04-23 19:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 12:45 [PATCH v2 1/1] tipc: fix double-free in tipc_buf_append() Lee Jones
2026-04-22 8:47 ` Tung Quang Nguyen
2026-04-23 19:10 ` patchwork-bot+netdevbpf
2026-04-23 19:10 ` Simon Horman [this message]
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