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
next prev parent 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
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