From: Xinglu Chen <public@yoctocell.xyz>
To: 48872@debbugs.gnu.org
Subject: bug#48872: Guix services: ‘chmod’ leaves opportunity to leak secrets
Date: Sun, 06 Jun 2021 14:51:36 +0200 [thread overview]
Message-ID: <87y2bn5f6v.fsf@yoctocell.xyz> (raw)
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[ This was reported on the Nixpkgs bug tracker a few weeks ago
<https://github.com/NixOS/nixpkgs/issues/121293> ]
When doing something like
(call-with-output-file FILE
(lambda (port)
(display SECRET port)))
(chmod FILE #o400)
an unpriviliged user could open FILE before FILE had been chmod’ed, and
then read the contents of FILE.
One solution to this problem would be to use
(mkdir (dirname FILE) #o400)
before writing SECRET to FILE.
I have identified at least two services which are vulnerable to this:
* ‘wireguard-service-type’ in (gnu services vpn)
* ‘patchwork-service-type’ in (gnu servicse web)
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next reply other threads:[~2021-06-06 12:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-06 12:51 Xinglu Chen [this message]
2021-06-08 8:55 ` bug#48872: Guix services: ‘chmod’ leaves opportunity to leak secrets Maxime Devos
2021-06-08 14:42 ` Xinglu Chen
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