[PATCH v5 0/1] Unprivileged chroot

Mickaël Salaün mic at digikod.net
Tue Mar 16 20:36:32 UTC 2021


This new patch fix a race (spotted by Jann Horn) when reading
current->fs->users .

The chroot system call is currently limited to be used by processes with
the CAP_SYS_CHROOT capability.  This protects against malicious
procesess willing to trick SUID-like binaries.  The following patch
allows unprivileged users to safely use chroot(2), which may be
complementary to the use of user namespaces.

This patch is a follow-up of a previous one sent by Andy Lutomirski some
time ago:

This patch can be applied on top of v5.12-rc3 .  I would really
appreciate constructive reviews.

Previous versions:
v4: https://lore.kernel.org/r/20210316170135.226381-1-mic@digikod.net
v3: https://lore.kernel.org/r/20210311105242.874506-1-mic@digikod.net
v2: https://lore.kernel.org/r/20210310181857.401675-1-mic@digikod.net
v1: https://lore.kernel.org/r/20210310161000.382796-1-mic@digikod.net


Mickaël Salaün (1):
  fs: Allow no_new_privs tasks to call chroot(2)

 fs/open.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

base-commit: 1e28eed17697bcf343c6743f0028cc3b5dd88bf0

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