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Re: [patch] libstdc++/67747 Allocate space for dirent::d_name
- From: Florian Weimer <fweimer at redhat dot com>
- To: Jonathan Wakely <jwakely at redhat dot com>, libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Fri, 2 Oct 2015 14:16:30 +0200
- Subject: Re: [patch] libstdc++/67747 Allocate space for dirent::d_name
- Authentication-results: sourceware.org; auth=none
- References: <20150929113726 dot GU12094 at redhat dot com>
On 09/29/2015 01:37 PM, Jonathan Wakely wrote:
> POSIX says that dirent::d_name has an unspecified length, so calls to
> readdir_r must pass a buffer with enough trailing space for
> {NAME_MAX}+1 characters. I wasn't doing that, which works OK on
> GNU/Linux and BSD where d_name is a large array, but fails on Solaris
> 32-bit.
>
> This uses pathconf to get NAME_MAX and allocates a buffer.
This still has a buffer overflow on certain file systems.
You must not use readdir_r, it is deprecated and always insecure. We
should probably mark it as such in the glibc headers.
Have we already released code which uses readdir_r?
Florian