Re: [PATCH] be paranoid about closed stdin/stdout/stderr

On Wed, Aug 27, 2008 at 02:22:39PM -0400, Avery Pennarun wrote:

I'm just feeling protective of the future sanity of other developers
here, hoping they don't have to go through what I did on a multi-week
bug hunt.  (We were even blaming reiserfs for a while for our boot
sector getting zapped...)  The fact that someone *other* than me has
suggested this change implies that I'm not the only one who has seen
such insanity in the wild.

You're not alone. I've been having trouble with a combination of
fetchmail, procmail and ssmtp, in which situation the ssmtp program
_somehow_ sometimes opens /dev/urandom as file descriptor 0 (while
calculating an SSL key?) and leaves it open, then reads the message
body from that file descriptor, resulting in an endless garbage message
being sent to the SMTP server.

I suspect the error originates in Debian's patch to ssmtp (which
added the SSL support) but I haven't been able to reproduce the bug
in controlled circumstances. It's possible that fetchmail or procmail
is doing something stupid - but a little more defensive programming
in ssmtp could avoid the total disaster area of sending an endless
binary stream to an SMTP server.

So although I'm not experiencing any problems with git due to incorrect
file descriptor usage, I'm sensitive to the general issue.

Nick.