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linux/net/unix
Kuniyuki Iwashima b94038d841 af_unix: Stop recv(MSG_PEEK) at consumed OOB skb.
After consuming OOB data, recv() reading the preceding data must break at
the OOB skb regardless of MSG_PEEK.

Currently, MSG_PEEK does not stop recv() for AF_UNIX, and the behaviour is
not compliant with TCP.

  >>> from socket import *
  >>> c1, c2 = socketpair(AF_UNIX)
  >>> c1.send(b'hello', MSG_OOB)
  5
  >>> c1.send(b'world')
  5
  >>> c2.recv(1, MSG_OOB)
  b'o'
  >>> c2.recv(9, MSG_PEEK)  # This should return b'hell'
  b'hellworld'              # even with enough buffer.

Let's fix it by returning NULL for consumed skb and unlinking it only if
MSG_PEEK is not specified.

This patch also adds test cases that add recv(MSG_PEEK) before each recv().

Without fix:

  #  RUN           msg_oob.peek.oob_ahead_break ...
  # msg_oob.c:134:oob_ahead_break:AF_UNIX :hellworld
  # msg_oob.c:135:oob_ahead_break:Expected:hell
  # msg_oob.c:137:oob_ahead_break:Expected ret[0] (9) == expected_len (4)
  # oob_ahead_break: Test terminated by assertion
  #          FAIL  msg_oob.peek.oob_ahead_break
  not ok 13 msg_oob.peek.oob_ahead_break

With fix:

  #  RUN           msg_oob.peek.oob_ahead_break ...
  #            OK  msg_oob.peek.oob_ahead_break
  ok 13 msg_oob.peek.oob_ahead_break

Fixes: 314001f0bf ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-06-27 12:05:00 +02:00
..
af_unix.c af_unix: Stop recv(MSG_PEEK) at consumed OOB skb. 2024-06-27 12:05:00 +02:00
diag.c af_unix: Annotate data-race of sk->sk_shutdown in sk_diag_fill(). 2024-06-06 12:57:15 +02:00
garbage.c af_unix: Fix garbage collection of embryos carrying OOB with SCM_RIGHTS 2024-05-21 13:42:02 +02:00
Kconfig af_unix: Remove CONFIG_UNIX_SCM. 2024-01-31 16:41:16 -08:00
Makefile af_unix: Remove CONFIG_UNIX_SCM. 2024-01-31 16:41:16 -08:00
sysctl_net_unix.c net: Remove the now superfluous sentinel elements from ctl_table array 2024-05-03 13:29:41 +01:00
unix_bpf.c bpf: sockmap, fix proto update hook to avoid dup calls 2024-01-03 16:50:06 -08:00