linux-kernel - Re: [PATCH v2] firmware: make sure paths remain relative

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 18 Dec 2012 22:02:23 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Kees Cook <keescook@...omium.org>
Cc:	linux-kernel@...r.kernel.org, Ming Lei <ming.lei@...onical.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v2] firmware: make sure paths remain relative

On Tue, 18 Dec 2012 13:04:49 -0800
Kees Cook <keescook@...omium.org> wrote:

> Some devices have configurable firmware locations. If these configuration
> mechanisms are exposed to unprivileged userspace, it may be possible to
> load firmware from an unexpected location. To minimize the risk of this,
> make sure the string "../" does not appear in the firmware name. This
> means that neither the users of request_firmware, nor the uevent handler
> have to do this filtering themselves.

Have you verified no existing distribution ever does this ?


> +	if (strstr(name, "../")) {

and this is obviously buggy and hasn't been tested

Hint foo/bar../baz

You need to check for ^../ /../ and /..$

Alan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/