Re: [Patch] Runtime interaction bug with sudo

[Jay Bosamiya <jaybosamiya () gmail com>]

Hi Patrick,

I read through all 3 links and rewrote the patch.
It now doesn't use exit but restores the default handler and raises the 
signal again (after calling tty_done).

Core dump generation is preserved. I tested that using `ulimit -c 
unlimited; sudo nmap 127.0.0.1 -p-` and then pressing Ctrl-\

One thing I'm not so sure of is the handlers for SIGPIPE, SIGHUP and 
SIGXFSZ being set to SIG_IGN. That's why I haven't included them in the 
patch, even though its there in the code you had written ([3] in your mail).

Other than that, the patch seems to work perfectly for all the tests I 
ran against it on my Ubuntu 14.04 machine.

I would appreciate it, if you could give any feedback for further 
improvement; otherwise, I think that the patch can be committed.

Cheers,
Jay

Attached: The new patch.

On Wednesday 14 May 2014 07:56 PM, Patrick Donnelly wrote:
> exit is not an "async-signal-safe" function as defined by [1]. The
> main reason for this is because it calls fflush on all open files.
>
> Calling tty_done directly from the signal handler would be okay
> though. [Although, technically, changing tty_fd in tty_done is not
> technically correct in a signal handler since its type is not
> sig_atomic_t.] Then you could call _exit [2] (which is
> async-signal-safe).
>
> Any solution to this should preserve the abnormal termination of Nmap.
> That is, the default signal handler should be restored and the signal
> raised again. The main reason for this is to preserve the generation
> of core dumps. You can look at an example solution I wrote for another
> program here [3].
>
> [1]http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html
> [2]http://pubs.opengroup.org/onlinepubs/009695399/functions/_exit.html
> [3]https://github.com/cooperative-computing-lab/cctools/blob/master/chirp/src/chirp_server.c#L1893

Attachment: keyStrokeGrabbing.patch.new
Description:

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