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From: Rich Felker <dalias@libc.org>
To: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: musl@lists.openwall.com
Subject: Re: [musl] realpath without procfs -- should be ready for inclusion
Date: Wed, 25 Nov 2020 10:03:58 -0500	[thread overview]
Message-ID: <20201125150357.GH534@brightrain.aerifal.cx> (raw)
In-Reply-To: <ebd3d249937ca5b34ac8aac04eb4158c@ispras.ru>

On Wed, Nov 25, 2020 at 08:40:02AM +0300, Alexey Izbyshev wrote:
> I don't see why the size of stack has to be PATH_MAX+1 though. To
> address the issue with symlink targets of PATH_MAX-1 length, it
> seems sufficient to just do the following:
> 
> -               ssize_t k = readlink(output, stack, p);
> -               if (k==p) goto toolong;
> +               ssize_t k = readlink(output, stack, p+1);
> +               if (k==p+1) goto toolong;
> 
> Since p is never past the end of the stack, there is no harm in
> allowing k == p.

Indeed. I think I was concerned about it clobbering the first byte of
the live part of the stack, but on error the stack is discarded
anyway, so that seems to be a non-issue.

Rich

  reply	other threads:[~2020-11-25 15:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-22 22:56 Rich Felker
2020-11-23  2:03 ` Alexey Izbyshev
2020-11-23  3:17   ` Érico Nogueira
2020-11-23  3:34     ` Rich Felker
2020-11-23  3:19   ` Rich Felker
2020-11-23 18:56     ` Rich Felker
2020-11-23 20:53       ` Rich Felker
2020-11-24  3:39         ` Alexey Izbyshev
2020-11-24  4:26           ` Rich Felker
2020-11-24  5:13             ` Alexey Izbyshev
2020-11-24  6:30               ` Rich Felker
2020-11-24  9:21                 ` Alexey Izbyshev
2020-11-24 14:35                   ` Rich Felker
2020-11-24 20:17                     ` Rich Felker
2020-11-25 15:02                   ` Rich Felker
2020-11-25 19:40                     ` Alexey Izbyshev
2020-11-24 20:31             ` Rich Felker
2020-11-25  5:40               ` Alexey Izbyshev
2020-11-25 15:03                 ` Rich Felker [this message]
2020-11-24  3:41     ` Alexey Izbyshev

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