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Message-ID: <20111022011903.GA31685@openwall.com>
Date: Sat, 22 Oct 2011 05:19:03 +0400
From: Solar Designer <solar@...nwall.com>
To: oss-security@...ts.openwall.com
Subject: Re: hardlink(1) has buffer overflows, is unsafe on changing trees
On Sat, Oct 22, 2011 at 04:56:21AM +0400, Solar Designer wrote:
> strcpy (p, di->d_name);
>
> where "p" points somewhere inside nambuf1.
>
> These will just need different reproducers.
Actually, I think my proposed reproducer (many nested 250-char dirs)
triggers this one and not the strcat(). On one build, hardlink then
crashes after dereferencing the "dirs" pointer, which happens to be
overwritten with a directory name. On another build (different gcc
version and arch), hardlink does not crash (although I think it would on
even more nested directories), but reports a ridiculous directory count
(so "ndirs" is overwritten). -D_FORTIFY_SOURCE=2 didn't make a
difference here (different program binary, same observed behavior).
Alexander
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