linux-kernel - Re: [PATCH v2 2/2] TTY: ntty, add one more sanity check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110607171043.GA1200@kroah.com>
Date:	Tue, 7 Jun 2011 10:10:43 -0700
From:	Greg KH <greg@...ah.com>
To:	Jiri Slaby <jslaby@...e.cz>
Cc:	gregkh@...e.de, jirislaby@...il.com, linux-kernel@...r.kernel.org,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [PATCH v2 2/2] TTY: ntty, add one more sanity check

On Tue, Jun 07, 2011 at 06:57:50PM +0200, Jiri Slaby wrote:
> On 06/07/2011 06:44 PM, Greg KH wrote:
> > On Sun, Jun 05, 2011 at 02:16:17PM +0200, Jiri Slaby wrote:
> >> With the previous patch, we fixed another bug where read_buf was freed
> >> while we still was in n_tty_read. We currently check whether read_buf
> >> is NULL at the start of the function. Add one more check after we wake
> >> up from waiting for input.
> >>
> >> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> >> Cc: Alan Cox <alan@...rguk.ukuu.org.uk>
> >> ---
> >>  drivers/tty/n_tty.c |    1 +
> >>  1 files changed, 1 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
> >> index 95d0a9c..c62c856 100644
> >> --- a/drivers/tty/n_tty.c
> >> +++ b/drivers/tty/n_tty.c
> >> @@ -1785,6 +1785,7 @@ do_it_again:
> >>  				break;
> >>  			}
> >>  			timeout = schedule_timeout(timeout);
> >> +			BUG_ON(!tty->read_buf);
> > 
> > So, if we ever hit this, what are we going to do with this crash?
> > 
> > I really don't want to add more BUG_ON() calls to the kernel if at all
> > possible.  Or is it the case that we will crash if this case is true
> > soon afterward anyway?
> 
> Yeah, it will crash something like 10 lines below. The pointer is
> dereferenced there.

Ok, fair enough, thanks.

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/