From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [patch] net/unix: do not forget to autobind in standard case
Date: Tue, 28 Dec 2010 17:44:15 +0100
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Cc: Linux Networking Developer Mailing List <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>
To: Jan Engelhardt <jengelh@medozas.de>
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Le samedi 25 d=C3=A9cembre 2010 =C3=A0 01:08 +0100, Jan Engelhardt a =C3=
=A9crit :
> parent 67514fc40bbec857018cbc689d440282b75551db (v2.6.37-rc1-229-g675=
14fc)
> commit 973bdc63c6aba703dd7b62a6ec7ae4bab7847731
> Author: Jan Engelhardt <jengelh@medozas.de>
> Date:   Sat Dec 25 00:50:59 2010 +0100
>=20
> net/unix: do not forget to autobind in standard case
>=20
> A program using recvmsg on an AF_LOCAL datagram socket does not
> receive the peer's address when the remote has not issued a bind. Thi=
s
> makes it impossible to send messages back. (But the same _does_ work
> in IP.) The cause for this is because autobinding was only done when
> credential passing was requested.
>=20

It would be good you did some research and tell us why current code
tests SOCK_PASSCRED

There must be a reason this restrictive code is here, dont you think ?

> --->8---
>=20
> Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
> ---
>  net/unix/af_unix.c |   10 ++++------
>  1 files changed, 4 insertions(+), 6 deletions(-)
>=20
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index 7ff31c6..945797c 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -964,8 +964,8 @@ static int unix_dgram_connect(struct socket *sock=
, struct sockaddr *addr,
>  			goto out;
>  		alen =3D err;
> =20
> -		if (test_bit(SOCK_PASSCRED, &sock->flags) &&
> -		    !unix_sk(sk)->addr && (err =3D unix_autobind(sock)) !=3D 0)
> +		if (unix_sk(sk)->addr =3D=3D NULL &&
> +		    (err =3D unix_autobind(sock)) !=3D 0)
>  			goto out;
> =20
>  restart:
> @@ -1063,8 +1063,7 @@ static int unix_stream_connect(struct socket *s=
ock, struct sockaddr *uaddr,
>  		goto out;
>  	addr_len =3D err;
> =20
> -	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
> -	    (err =3D unix_autobind(sock)) !=3D 0)
> +	if (u->addr =3D=3D NULL && (err =3D unix_autobind(sock)) !=3D 0)
>  		goto out;
> =20
>  	timeo =3D sock_sndtimeo(sk, flags & O_NONBLOCK);
> @@ -1419,8 +1418,7 @@ static int unix_dgram_sendmsg(struct kiocb *kio=
cb, struct socket *sock,
>  			goto out;
>  	}
> =20
> -	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
> -	    && (err =3D unix_autobind(sock)) !=3D 0)
> +	if (u->addr =3D=3D NULL && (err =3D unix_autobind(sock)) !=3D 0)
>  		goto out;
> =20
>  	err =3D -EMSGSIZE;