zsh-workers
 help / color / mirror / code / Atom feed
From: Peter Stephenson <p.w.stephenson@ntlworld.com>
To: zsh-workers@zsh.org
Subject: Re: PATCH: utils.c: Fix use of uninitialized memory in metafy().
Date: Wed, 27 Nov 2013 20:26:02 +0000	[thread overview]
Message-ID: <20131127202602.3897f501@pws-pc.ntlworld.com> (raw)
In-Reply-To: <131127105409.ZM10472@torch.brasslantern.com>

On Wed, 27 Nov 2013 10:54:09 -0800
Bart Schaefer <schaefer@brasslantern.com> wrote:
> On Nov 27,  6:07pm, Peter Stephenson wrote:
> } 
> } Hmm... I think the intention probably *is* to check if there's null
> } termination at "buf + len", on the assumption that the first "len" bytes
> } need metafying regardless.  So if we've got only len valid bytes, not
> } null-terminated (or null-terminated by accident because the next byte
> } that isn't actually valid for the allocation happens to be null), we've
> } got no way of knowing this given the current interface.
> 
> Does it actually matter?  The only reason for (*e != 0) as far as I can
> tell is to be sure we've actually done (*e = '\0') at the very end of
> the whole thing [comment: "... unchanged (a terminating null character
> is appended to buf if necessary)"].
> 
> Can't we just move the *e = '\0' outside the "if" body and skip the test
> in the condition?

Seems reasonable --- it requires the problem Simon was seeing to be in a
case that's requesting reallocation, else that assignment is going to
cause problems, but if it does cause problems we need to change the
caller.

pws


  reply	other threads:[~2013-11-27 20:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-27 17:45 Simon Ruderich
2013-11-27 18:07 ` Peter Stephenson
2013-11-27 18:54   ` Bart Schaefer
2013-11-27 20:26     ` Peter Stephenson [this message]
2013-11-28  1:19       ` Bart Schaefer
2013-11-28  9:40         ` Peter Stephenson

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=20131127202602.3897f501@pws-pc.ntlworld.com \
    --to=p.w.stephenson@ntlworld.com \
    --cc=zsh-workers@zsh.org \
    /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.
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/zsh/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).