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From: Simon Horman <horms@kernel.org>
To: Xiang Mei <xmei5@asu.edu>
Cc: kuba@kernel.org, netdev@vger.kernel.org, davem@davemloft.net,
	yotam.gi@gmail.com, edumazet@google.com, pabeni@redhat.com,
	bestswngs@gmail.com
Subject: Re: [PATCH net v2] psample: use nla_reserve() for PSAMPLE_ATTR_DATA
Date: Mon, 15 Jun 2026 14:09:03 +0100	[thread overview]
Message-ID: <20260615130903.GM712698@horms.kernel.org> (raw)
In-Reply-To: <20260614034919.918494-1-xmei5@asu.edu>

On Sat, Jun 13, 2026 at 08:49:19PM -0700, Xiang Mei wrote:
> psample_sample_packet() open-codes the PSAMPLE_ATTR_DATA attribute and
> reserves nla_total_size(data_len) bytes but only writes NLA_HDRLEN +
> data_len of them.  When data_len is not a multiple of 4 the trailing
> alignment padding is left uninitialised, leaking stale slab memory to
> every listener on the PSAMPLE_NL_MCGRP_SAMPLE multicast group.
> 
> Use nla_reserve(), which lays out the header and zeroes the padding, and
> copy the payload into the reserved area with skb_copy_bits().
> 
> Fixes: 6ae0a6286171 ("net: Introduce psample, a new genetlink channel for packet sampling")
> Reported-by: Weiming Shi <bestswngs@gmail.com>
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Xiang Mei <xmei5@asu.edu>
> ---
> v2: use nla_reserve to ensure no info leak

Reviewed-by: Simon Horman <horms@kernel.org>


      reply	other threads:[~2026-06-15 13:09 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-14  3:49 [PATCH net v2] psample: use nla_reserve() for PSAMPLE_ATTR_DATA Xiang Mei
2026-06-15 13:09 ` Simon Horman [this message]

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