2 Commits

Author SHA1 Message Date
Aleksa Sarai
4e62d55d77
selftests: openat2: add RESOLVE_ conflict test
Now that we reject conflicting RESOLVE_ flags, add a selftest to avoid
regressions.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20201027235044.5240-3-cyphar@cyphar.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-12-03 10:16:28 +01:00
Aleksa Sarai
b28a10aedc selftests: add openat2(2) selftests
Test all of the various openat2(2) flags. A small stress-test of a
symlink-rename attack is included to show that the protections against
".."-based attacks are sufficient.

The main things these self-tests are enforcing are:

  * The struct+usize ABI for openat2(2) and copy_struct_from_user() to
    ensure that upgrades will be handled gracefully (in addition,
    ensuring that misaligned structures are also handled correctly).

  * The -EINVAL checks for openat2(2) are all correctly handled to avoid
    userspace passing unknown or conflicting flag sets (most
    importantly, ensuring that invalid flag combinations are checked).

  * All of the RESOLVE_* semantics (including errno values) are
    correctly handled with various combinations of paths and flags.

  * RESOLVE_IN_ROOT correctly protects against the symlink rename(2)
    attack that has been responsible for several CVEs (and likely will
    be responsible for several more).

Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-01-18 09:19:18 -05:00