On 2013/4/4 10:13, Eric W. Biederman wrote:
>
> This reverts commit 14134f6584212d585b310ce95428014b653dfaf6.
>
> The problem that the above patch was meant to address is that af_unix
> messages are not being coallesced because we are sending unnecesarry
> credentials. Not sending credentials in maybe_add_creds totally
> breaks unconnected unix domain sockets that wish to send credentails
> to other sockets.
>
thanks for check the question and make a fix solution, but I still doubt that if unconnected unix
domain socket wish to send credentails to oher sockets, why dont set
SOCK_PASSCRED on sock->flags, I think the user need to decide the param
and shouldnt send creds by default way.
Ding
> In practice this break some versions of udev because they receive a
> message and the sending uid is bogus so they drop the message.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Sven Joachim <svenjoac@xxxxxx>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> ---
> net/unix/af_unix.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index 971282b..f153a8d 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -1412,8 +1412,8 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
> if (UNIXCB(skb).cred)
> return;
> if (test_bit(SOCK_PASSCRED, &sock->flags) ||
> - (other->sk_socket &&
> - test_bit(SOCK_PASSCRED, &other->sk_socket->flags))) {
> + !other->sk_socket ||
> + test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
> UNIXCB(skb).pid = get_pid(task_tgid(current));
> UNIXCB(skb).cred = get_current_cred();
> }
>
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