selftests: core: include linux/close_range.h for CLOSE_RANGE_* macros

Correct header file is needed for getting CLOSE_RANGE_* macros.
Previously it was tested with newer glibc which didn't show the need to
include the header which was a mistake.

Link: https://lkml.kernel.org/r/20231024155137.219700-1-usama.anjum@collabora.com
Fixes: ec54424923cf ("selftests: core: remove duplicate defines")
Reported-by: Aishwarya TCV <aishwarya.tcv@arm.com>
Link: https://lore.kernel.org/all/7161219e-0223-d699-d6f3-81abd9abf13b@arm.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests: core: remove duplicate defines

Remove duplicate defines which are already defined in kernel headers and
re-definition isn't required.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/core: remove ARRAY_SIZE define from close_range_test.c

ARRAY_SIZE is defined in several selftests. Remove definitions from
individual test files and include header file for the define instead.
ARRAY_SIZE define is added in a separate patch to prepare for this
change.

Remove ARRAY_SIZE from close_range_test.c and pickup the one defined
in kselftest.h.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/core: fix conflicting types compile error for close_range()

close_range() test type conflicts with close_range() library call in
x86_64-linux-gnu/bits/unistd_ext.h. Fix it by changing the name to
core_close_range().

gcc -g -I../../../../usr/include/ close_range_test.c -o ../tools/testing/selftests/core/close_range_test
In file included from close_range_test.c:16:
close_range_test.c:57:6: error: conflicting types for ‘close_range’; have ‘void(struct __test_metadata *)’
57 | TEST(close_range)
| ^~~~~~~~~~~
../kselftest_harness.h:181:21: note: in definition of macro ‘__TEST_IMPL’
181 | static void test_name(struct __test_metadata *_metadata); \
| ^~~~~~~~~
close_range_test.c:57:1: note: in expansion of macro ‘TEST’
57 | TEST(close_range)
| ^~~~
In file included from /usr/include/unistd.h:1204,
from close_range_test.c:13:
/usr/include/x86_64-linux-gnu/bits/unistd_ext.h:56:12: note: previous declaration of ‘close_range’ with type ‘int(unsigned int, unsigned int, int)’
56 | extern int close_range (unsigned int __fd, unsigned int __max_fd,
| ^~~~~~~~~~~

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/core: add regression test for CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC

This test is a minimalized version of the reproducer given by syzbot
(cf. [1]).

After introducing CLOSE_RANGE_CLOEXEC syzbot reported a crash when
CLOSE_RANGE_CLOEXEC is specified in conjunction with
CLOSE_RANGE_UNSHARE. When CLOSE_RANGE_UNSHARE is specified the caller
will receive a private file descriptor table in case their file
descriptor table is currently shared.
For the case where the caller has requested all file descriptors to be
actually closed via e.g. close_range(3, ~0U, 0) the kernel knows that
the caller does not need any of the file descriptors anymore and will
optimize the close operation by only copying all files in the range from
0 to 3 and no others.

However, if the caller requested CLOSE_RANGE_CLOEXEC together with
CLOSE_RANGE_UNSHARE the caller wants to still make use of the file
descriptors so the kernel needs to copy all of them and can't optimize.

The original patch didn't account for this and thus could cause oopses
as evidenced by the syzbot report. Add tests for this regression.

We first create a huge gap in the fd table. When we now call
CLOSE_RANGE_UNSHARE with a shared fd table and and with ~0U as upper
bound the kernel will only copy up to fd1 file descriptors into the new
fd table. If the kernel is buggy and doesn't handle CLOSE_RANGE_CLOEXEC
correctly it will not have copied all file descriptors and we will oops!

This test passes on a fixed kernel and will trigger an oops on a buggy
kernel.

[1]: https://syzkaller.appspot.com/text?tag=KernelConfig&x=db720fe37a6a41d8

Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Link: syzbot+96cfd2b22b3213646a93@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20201218145415.801063-4-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests/core: add test for CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC

Add a test to verify that CLOSE_RANGE_UNSHARE works correctly when combined
with CLOSE_RANGE_CLOEXEC for the single-threaded case.

Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20201218145415.801063-3-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests/core: handle missing syscall number for close_range

This improves the syscall number handling in the close_range()
selftests. This should handle any architecture.

Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20201218145415.801063-2-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests/core: fix close_range_test build after XFAIL removal

XFAIL was removed in commit 9847d24af95c ("selftests/harness: Refactor
XFAIL into SKIP") and its use in close_range_test was already replaced
by commit 1d44d0dd61b6 ("selftests: core: use SKIP instead of XFAIL in
close_range_test.c"). However, commit 23afeaeff3d9 ("selftests: core:
add tests for CLOSE_RANGE_CLOEXEC") introduced usage of XFAIL in
TEST(close_range_cloexec). Use SKIP there as well.

Fixes: 23afeaeff3d9 ("selftests: core: add tests for CLOSE_RANGE_CLOEXEC")
Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20201218112428.13662-1-tklauser@distanz.ch
Link: https://lore.kernel.org/r/20201218145415.801063-1-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests: core: add tests for CLOSE_RANGE_CLOEXEC

check that close_range(initial_fd, last_fd, CLOSE_RANGE_CLOEXEC)
correctly sets the close-on-exec bit for the specified file
descriptors.

Open 100 file descriptors and set the close-on-exec flag for a subset
of them first, then set it for every file descriptor above 2. Make
sure RLIMIT_NOFILE doesn't affect the result.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Link: https://lore.kernel.org/r/20201118104746.873084-3-gscrivan@redhat.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests: core: use SKIP instead of XFAIL in close_range_test.c

XFAIL is gone since commit 9847d24af95c ("selftests/harness: Refactor XFAIL
into SKIP"), use SKIP instead.

Fixes: 9847d24af95c ("selftests/harness: Refactor XFAIL into SKIP")
Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tests: add CLOSE_RANGE_UNSHARE tests

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

tests: add close_range() tests

This adds basic tests for the new close_range() syscall.
- test that no invalid flags can be passed
- test that a range of file descriptors is correctly closed
- test that a range of file descriptors is correctly closed if there there
are already closed file descriptors in the range
- test that max_fd is correctly capped to the current fdtable maximum

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jann Horn <jannh@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-api@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org