From: Jeff King <peff@peff.net>
Date: Tue, 07 Jul 2015 14:33:50 GMT
Subject: Re: [PATCH] Change strbuf_read_file() to return ssize_t
Message-ID: <20150707143350.GB629@peff.net>
In-Reply-To: <74f6ccbe74486b1d5589e953c4cf6d39c82c5c05.1435931485.git.mhagger@alum.mit.edu>

On Fri, Jul 03, 2015 at 03:59:32PM +0200, Michael Haggerty wrote:

> It is currently declared to return int, which could overflow for large
> files.
> 
> Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
> ---
> This patch is against maint, but it also rebases against master
> without conflict.
> 
> I couldn't find any way to exploit this bug. Most callers only use
> this function for locally-generated files in the first place. And the
> correct length of the file is available in strbuf::len, so most
> callers only use the return value for a "< 0" check. And they don't do
> anything risky on the error path.

FWIW, I also looked for problem areas, but couldn't find anything
interesting. But this seems like an obviously good thing to be doing
anyway.

I also wondered if any callers needed to adjust their storage for the
return type to ssize_t (i.e., are we just moving the truncation up one
assignment). But there is only a single caller that assigns the result,
and it uses an ssize_t already.

-Peff