Aleksa Sarai 0337bb53cb procfs: block chmod on /proc/thread-self/comm
commit ccf61486fe1e1a48e18c638d1813cda77b3c0737 upstream.

Due to an oversight in commit 1b3044e39a89 ("procfs: fix pthread
cross-thread naming if !PR_DUMPABLE") in switching from REG to NOD,
chmod operations on /proc/thread-self/comm were no longer blocked as
they are on almost all other procfs files.

A very similar situation with /proc/self/environ was used to as a root
exploit a long time ago, but procfs has SB_I_NOEXEC so this is simply a
correctness issue.

Ref: https://lwn.net/Articles/191954/
Ref: 6d76fa58b050 ("Don't allow chmod() on the /proc/<pid>/ files")
Fixes: 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Message-Id: <20230713141001.27046-1-cyphar@cyphar.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-09-23 10:59:55 +02:00
..
2023-06-21 15:44:12 +02:00
2023-08-11 11:53:59 +02:00
2021-09-22 12:26:25 +02:00
2022-06-14 18:11:36 +02:00
2023-07-27 08:37:06 +02:00
2023-02-22 12:50:35 +01:00
2022-06-14 18:11:41 +02:00
2020-10-01 13:17:19 +02:00
2023-01-18 11:41:44 +01:00