linux/tools
Christian Brauner df4b2889ea
selftests/filesystems: add failfs selftests
Test the failfs semantics and both new entry points:

- fchdir(FD_FAILFS_ROOT):

  * working directory lookups and getcwd() fail
  * other sentinels are rejected
  * the state is recoverable while the root is untouched

- fchroot() with regular fds:
  * chroot parity
  * CAP_SYS_CHROOT required
  * ENOTDIR/EBADF/EINVAL checks

- fchroot(FD_FAILFS_ROOT):

  * absolute lookups, stat, statfs and opens of the root including O_PATH fail with EOPNOTSUPP
  * dirfd-anchored I/O keeps working
  * ".." walks clamp at the top of the mount tree
  * /proc magic links resolve but can't be stat through
  * absolute symlinks fail while relative symlinks keep resolving

- Unprivileged entry requires no_new_privs and is rejected for
  chrooted callers and for a shared fs_struct

- entering makes the task count as chrooted so user namespace creation
  fails

- Nothing can be mounted on top of failfs and OPEN_TREE_CLONE is
  rejected; the overmount test runs in a private mount namespace so a
  regression cannot touch the host root

- setns() to a kept mount namespace fd restores root and working
  directory

- The failfs root is inherited across fork() and absolute exec fails

- Exec by fd of a dynamically linked binary fails on opening its
  absolute PT_INTERP interpreter

The exec tests run the exec in a child so a wrongly successful exec
cannot replace the test image and masquerade as a pass.

Link: https://patch.msgid.link/20260724-work-failfs-v2-6-485dabbae185@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-07-27 17:18:00 +02:00
..
accounting tools/accounting/getdelays: fix -Wformat-truncation warning in format_timespec 2026-05-28 21:24:40 -07:00
arch perf tools changes for v7.2: 2026-06-23 11:34:49 -07:00
bootconfig Bootconfig updates for v7.2 2026-06-16 17:29:24 +05:30
bpf bpftool: Fix vmlinux BTF leak in cgroup commands 2026-06-21 18:02:10 -07:00
build perf tools changes for v7.2: 2026-06-23 11:34:49 -07:00
certs
cgroup
counter
crypto
debugging
dma
docs
firewire
firmware
gpio
hv
iio iio: core: Add IIO_COVERAGE channel type 2026-05-31 11:01:50 +01:00
include arch: hookup fchroot() system call 2026-07-27 17:18:00 +02:00
kvm/kvm_stat
laptop
leds
lib A handful of late-arriving docs fixes, along with one document update 2026-06-25 09:09:38 -07:00
memory-model
mm slab changes for 7.2 - part 2 2026-06-22 08:28:48 -07:00
net tools/ynl: add missing uapi header deps in Makefile.deps 2026-06-24 19:30:55 -07:00
objtool
pcmcia
perf arch: hookup fchroot() system call 2026-07-27 17:18:00 +02:00
power platform-drivers-x86 for v7.2-1 2026-06-23 08:31:33 -07:00
rcu
sched
sched_ext tools/sched_ext: scx - Fix cmask_subset(), cmask_equal() and cmask_weight() 2026-07-09 11:08:41 -10:00
scripts arch: hookup fchroot() system call 2026-07-27 17:18:00 +02:00
sound
spi
testing selftests/filesystems: add failfs selftests 2026-07-27 17:18:00 +02:00
thermal
time
tracing rtla: Also link in ctype.c 2026-07-08 10:38:18 +02:00
unittests docs: kernel-doc: python: strip __counted_by_ptr macro 2026-05-15 08:11:36 -06:00
usb usbip: tools: support SuperSpeedPlus devices 2026-07-08 13:29:13 +02:00
verification verification/rvgen: Fix ltl2k writing True as a literal 2026-06-04 16:44:25 +02:00
virtio tools/virtio: add missing compat definitions for vhost_net_test 2026-07-01 19:02:56 -07:00
wmi
workqueue
writeback
Makefile