selftests: net: add SCM_PIDFD / SO_PEERPIDFD test

Basic test to check consistency between:
- SCM_CREDENTIALS and SCM_PIDFD
- SO_PEERCRED and SO_PEERPIDFD

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

af_unix: Add test for sock_diag and UDIAG_SHOW_UID.

The test prog dumps a single AF_UNIX socket's UID with and without
unshare(CLONE_NEWUSER) and checks if it matches the result of getuid().

Without the preceding patch, the test prog is killed by a NULL deref
in sk_diag_dump_uid().

# ./diag_uid
TAP version 13
1..2
# Starting 2 tests from 3 test cases.
# RUN diag_uid.uid.1 ...
BUG: kernel NULL pointer dereference, address: 0000000000000270
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 105212067 P4D 105212067 PUD 1051fe067 PMD 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014
RIP: 0010:sk_diag_fill (./include/net/sock.h:920 net/unix/diag.c:119 net/unix/diag.c:170)
...
# 1: Test terminated unexpectedly by signal 9
# FAIL diag_uid.uid.1
not ok 1 diag_uid.uid.1
# RUN diag_uid.uid_unshare.1 ...
# 1: Test terminated by timeout
# FAIL diag_uid.uid_unshare.1
not ok 2 diag_uid.uid_unshare.1
# FAILED: 0 / 2 tests passed.
# Totals: pass:0 fail:2 xfail:0 xpass:0 skip:0 error:0

With the patch, the test succeeds.

# ./diag_uid
TAP version 13
1..2
# Starting 2 tests from 3 test cases.
# RUN diag_uid.uid.1 ...
# OK diag_uid.uid.1
ok 1 diag_uid.uid.1
# RUN diag_uid.uid_unshare.1 ...
# OK diag_uid.uid_unshare.1
ok 2 diag_uid.uid_unshare.1
# PASSED: 2 / 2 tests passed.
# Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

selftests: net: af_unix: Test connect() with different netns.

This patch add a test that checks connect()ivity between two sockets:

unnamed socket -> bound socket
* SOCK_STREAM or SOCK_DGRAM
* pathname or abstract
* same or different netns

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

selftests: net: af_unix: Fix makefile to use TEST_GEN_PROGS

Makefile uses TEST_PROGS instead of TEST_GEN_PROGS to define
executables. TEST_PROGS is for shell scripts that need to be
installed and run by the common lib.mk framework. The common
framework doesn't touch TEST_PROGS when it does build and clean.

As a result "make kselftest-clean" and "make clean" fail to remove
executables. Run and install work because the common framework runs
and installs TEST_PROGS. Build works because the Makefile defines
"all" rule which is unnecessary if TEST_GEN_PROGS is used.

Use TEST_GEN_PROGS so the common framework can handle build/run/
install/clean properly.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

af_unix: Add OOB support

This patch adds OOB support for AF_UNIX sockets.
The semantics is same as TCP.

The last byte of a message with the OOB flag is
treated as the OOB byte. The byte is separated into
a skb and a pointer to the skb is stored in unix_sock.
The pointer is used to enforce OOB semantics.

Signed-off-by: Rao Shoaib <rao.shoaib@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>