From: Andrew Morton <andrewm@uow.edu.au>
To: Seth Andrew Hallem <shallem@Stanford.EDU>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Potential free/use-after-free bugs
Date: Sat, 17 Mar 2001 22:31:04 +1100 [thread overview]
Message-ID: <3AB34AF8.B09D69CA@uow.edu.au> (raw)
In-Reply-To: <20010316221730.B17586@elaine23.stanford.edu>
Seth Andrew Hallem wrote:
>
> I also have some questions regarding skbs. Our checker
> found a lot of instances where the skb is freed, then its length field is
> accessed. I have included an example location below. Is this a bug or
> not?
Yes, we should regard it as a bug.
A dev_kfree_skb_irq(skb) followed by a reference to *skb
is in fact safe, because the skb isn't freed until after the
interrupt function returns. But it's cruddy code and should be
changed.
Arnaldo recently went through a whole bunch of drivers fixing
a similar problem:
netif_rx(skb);
diddle_with(skb);
This is poor form because netif_rx() "gives away"
the skb and it's no longer yours to diddle with. In theory,
netif_rx() could have kfree'ed it on the spot.
With regard to the "16 potential locking bugs" email: nice
one. They all appear to be complete box-busting shockers.
If there was anyone around to send patches to, I'd fix em :)
But I'll hang on to that email and make sure everything is ticked
off next month. So: ack and thanks.
-
next prev parent reply other threads:[~2001-03-17 11:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-17 6:17 Potential free/use-after-free bugs Seth Andrew Hallem
2001-03-17 11:31 ` Andrew Morton [this message]
2001-03-17 21:47 ` Greg KH
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3AB34AF8.B09D69CA@uow.edu.au \
--to=andrewm@uow.edu.au \
--cc=linux-kernel@vger.kernel.org \
--cc=shallem@Stanford.EDU \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.