Hi, 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: https://lore.kernel.org/lkml/0e2f0f54e19bff53a3739ecfddb4ffa9a6dbde4d.1327858005.git.luto@xxxxxxxxxxxxxx/ 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@xxxxxxxxxxx v3: https://lore.kernel.org/r/20210311105242.874506-1-mic@xxxxxxxxxxx v2: https://lore.kernel.org/r/20210310181857.401675-1-mic@xxxxxxxxxxx v1: https://lore.kernel.org/r/20210310161000.382796-1-mic@xxxxxxxxxxx Regards, 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 -- 2.30.2
