From: Richard Weinberger <richard@nod.at>
To: alx@kernel.org, serge@hallyn.com, christian@brauner.io,
ipedrosa@redhat.com, gscrivan@redhat.com,
andreas.gruenbacher@gmail.com
Cc: acl-devel@nongnu.org, linux-man@vger.kernel.org,
linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
ebiederm@xmission.com, Richard Weinberger <richard@nod.at>
Subject: [PATCH 3/3] man: Document pitfall with negative permissions and user namespaces
Date: Tue, 29 Aug 2023 22:58:33 +0200 [thread overview]
Message-ID: <20230829205833.14873-4-richard@nod.at> (raw)
In-Reply-To: <20230829205833.14873-1-richard@nod.at>
It is little known that user namespaces and some helpers
can be used to bypass negative permissions.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
This patch applies to the shadow project.
---
man/subgid.5.xml | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/man/subgid.5.xml b/man/subgid.5.xml
index e473768d..8ed281e5 100644
--- a/man/subgid.5.xml
+++ b/man/subgid.5.xml
@@ -55,6 +55,15 @@
<filename>/etc/subgid</filename> if subid delegation is managed via subid
files.
</para>
+ <para>
+ Additionally, it's worth noting that the utilization of subordinate group
+ IDs can affect the enforcement of negative permissions. User can drop their
+ supplementary groups and bypass certain negative permissions.
+ For more details see
+ <citerefentry>
+ <refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum>
+ </citerefentry>.
+ </para>
</refsect1>
<refsect1 id='local-subordinate-delegation'>
--
2.35.3
next prev parent reply other threads:[~2023-08-29 20:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-29 20:58 [PATCH 0/3] Document impact of user namespaces and negative permissions Richard Weinberger
2023-08-29 20:58 ` [PATCH 1/3] man: Document pitfall with negative permissions and user namespaces Richard Weinberger
2023-08-30 8:19 ` Christian Brauner
2023-08-29 20:58 ` [PATCH 2/3] user_namespaces.7: " Richard Weinberger
2023-08-29 21:32 ` Alejandro Colomar
2023-08-29 21:38 ` Alejandro Colomar
2023-08-29 21:40 ` Richard Weinberger
2023-08-29 21:39 ` Richard Weinberger
2023-08-29 21:40 ` Alejandro Colomar
2023-08-30 9:26 ` Alejandro Colomar
2023-08-30 8:18 ` Christian Brauner
2023-08-29 20:58 ` Richard Weinberger [this message]
2023-08-30 8:19 ` [PATCH 3/3] man: " Christian Brauner
2023-08-29 21:26 ` [PATCH 0/3] Document impact of user namespaces and negative permissions Alejandro Colomar
2023-08-29 21:32 ` Richard Weinberger
2023-09-13 14:35 ` Alejandro Colomar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230829205833.14873-4-richard@nod.at \
--to=richard@nod.at \
--cc=acl-devel@nongnu.org \
--cc=alx@kernel.org \
--cc=andreas.gruenbacher@gmail.com \
--cc=christian@brauner.io \
--cc=ebiederm@xmission.com \
--cc=gscrivan@redhat.com \
--cc=ipedrosa@redhat.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-man@vger.kernel.org \
--cc=serge@hallyn.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).