linux

iv/linux

History

Kuniyuki Iwashima 22dd70eb2c af_unix: Don't peek OOB data without MSG_OOB.

Currently, we can read OOB data without MSG_OOB by using MSG_PEEK
when OOB data is sitting on the front row, which is apparently
wrong.

  >>> from socket import *
  >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
  >>> c1.send(b'a', MSG_OOB)
  1
  >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
  b'a'

If manage_oob() is called when no data has been copied, we only
check if the socket enables SO_OOBINLINE or MSG_PEEK is not used.
Otherwise, the skb is returned as is.

However, here we should return NULL if MSG_PEEK is set and no data
has been copied.

Also, in such a case, we should not jump to the redo label because
we will be caught in the loop and hog the CPU until normal data
comes in.

Then, we need to handle skb == NULL case with the if-clause below
the manage_oob() block.

With this patch:

  >>> from socket import *
  >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
  >>> c1.send(b'a', MSG_OOB)
  1
  >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  BlockingIOError: [Errno 11] Resource temporarily unavailable

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240410171016.7621-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2024-04-12 19:05:49 -07:00

af_unix.c

af_unix: Don't peek OOB data without MSG_OOB.

2024-04-12 19:05:49 -07:00

diag.c

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-02-01 15:12:37 -08:00

garbage.c

af_unix: Fix garbage collector racing against connect()

2024-04-11 09:46:15 +02:00

Kconfig

af_unix: Remove CONFIG_UNIX_SCM.