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From: David Miller <davem@davemloft.net>
To: johannes@sipsolutions.net
Cc: netdev@vger.kernel.org, richardcochran@gmail.com
Subject: Re: [RFC] net: remove erroneous sk null assignment in timestamping
Date: Fri, 07 Oct 2011 13:33:56 -0400 (EDT)	[thread overview]
Message-ID: <20111007.133356.489094996618032061.davem@davemloft.net> (raw)
In-Reply-To: <1318007501.3988.20.camel@jlt3.sipsolutions.net>

From: Johannes Berg <johannes@sipsolutions.net>
Date: Fri, 07 Oct 2011 19:11:41 +0200

> From: Johannes Berg <johannes.berg@intel.com>
> 
> skb->sk is obviously required to be non-NULL
> when we get into skb_complete_tx_timestamp().
> sock_queue_err_skb() will call skb_orphan()
> first thing which sets skb->sk = NULL itself.
> This may crash if the skb is still charged to
> the socket (skb->destructor is sk_wfree).
> 
> The assignment here thus seems to not only be
> pointless (due to the skb_orphan() call) but
> also dangerous (due to the crash).
> 
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

It looks like skb_clone_tx_timestamp() sets clone->sk without any
proper refcounting, so I bet this NULL'ing it out is working
around that bug.

The TX side of this infrastructure seems very poorly tested.

  reply	other threads:[~2011-10-07 17:35 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-07 17:11 [RFC] net: remove erroneous sk null assignment in timestamping Johannes Berg
2011-10-07 17:33 ` David Miller [this message]
2011-10-07 17:40   ` Johannes Berg
2011-10-07 17:47     ` Johannes Berg
2011-10-07 17:53       ` Johannes Berg
2011-10-07 18:42     ` Johannes Berg
2011-10-08  7:59       ` Richard Cochran
2011-10-08  7:57   ` Richard Cochran
2011-10-08  8:16     ` Johannes Berg
2011-10-08  8:57       ` Eric Dumazet
2011-10-08 10:32         ` Johannes Berg
2011-10-11 13:34           ` Richard Cochran
2011-10-08 10:35         ` Richard Cochran
2011-10-12 18:36 ` [PATCH 1/1] net: hold sock reference while processing tx timestamps Richard Cochran
2011-10-12 19:25   ` Eric Dumazet
2011-10-12 19:27   ` Johannes Berg
2011-10-12 19:52     ` Eric Dumazet
2011-10-13  8:54       ` Johannes Berg
2011-10-13  4:51     ` Richard Cochran
2011-10-13  9:46   ` [PATCH 0/3] net: time stamping fixes Richard Cochran
2011-10-19  4:16     ` David Miller
2011-10-19  5:15       ` Johannes Berg
2011-10-19 11:50         ` Richard Cochran
2011-10-19 12:33           ` Eric Dumazet
2011-10-19 12:38           ` Eric Dumazet
2011-10-19 12:58             ` Johannes Berg
2011-10-19 13:09               ` Johannes Berg
2011-10-19 13:25                 ` Eric Dumazet
2011-10-19 13:35                   ` Johannes Berg
2011-10-19 13:44                     ` Eric Dumazet
2011-10-19 13:57                       ` Johannes Berg
2011-10-19 14:08                         ` Eric Dumazet
2011-10-19 14:24                           ` Johannes Berg
2011-10-19 14:27                             ` Richard Cochran
2011-10-19 14:33                               ` Eric Dumazet
2011-10-19 13:21               ` Eric Dumazet
2011-10-19 13:25                 ` Johannes Berg
2011-10-19 13:27                   ` Eric Dumazet
2011-10-19 13:32                     ` Johannes Berg
2011-10-19 14:25                       ` Richard Cochran
2011-10-13  9:46   ` [PATCH 1/3] net: hold sock reference while processing tx timestamps Richard Cochran
2011-10-19  4:42     ` Eric Dumazet
2011-10-13  9:46   ` [PATCH 2/3] dp83640: use proper function to free transmit time stamping packets Richard Cochran
2011-10-19  4:47     ` Eric Dumazet
2011-10-13  9:46   ` [PATCH 3/3] dp83640: free packet queues on remove Richard Cochran
2011-10-19  4:48     ` Eric Dumazet
2011-10-21 10:49   ` [PATCH v2 0/3] net: time stamping fixes Richard Cochran
2011-10-21 10:49   ` [PATCH v2 1/3] net: hold sock reference while processing tx timestamps Richard Cochran
2011-10-21 11:31     ` Eric Dumazet
2011-10-24  6:55       ` David Miller
2011-10-21 11:44     ` Johannes Berg
2011-10-21 10:49   ` [PATCH v2 2/3] dp83640: use proper function to free transmit time stamping packets Richard Cochran
2011-10-24  6:55     ` David Miller
2011-10-24 17:47       ` Richard Cochran
2011-10-24 23:16         ` David Miller
2011-10-21 10:49   ` [PATCH v2 3/3] dp83640: free packet queues on remove Richard Cochran

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