| Message ID | alpine.LNX.2.01.1012250107330.22521@obet.zrqbmnf.qr |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
Le samedi 25 décembre 2010 à 01:08 +0100, Jan Engelhardt a écrit : > parent 67514fc40bbec857018cbc689d440282b75551db (v2.6.37-rc1-229-g67514fc) > commit 973bdc63c6aba703dd7b62a6ec7ae4bab7847731 > Author: Jan Engelhardt <jengelh@medozas.de> > Date: Sat Dec 25 00:50:59 2010 +0100 > > net/unix: do not forget to autobind in standard case > > 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. This > 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. > 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--- > > Signed-off-by: Jan Engelhardt <jengelh@medozas.de> > --- > net/unix/af_unix.c | 10 ++++------ > 1 files changed, 4 insertions(+), 6 deletions(-) > > 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 = err; > > - if (test_bit(SOCK_PASSCRED, &sock->flags) && > - !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) > + if (unix_sk(sk)->addr == NULL && > + (err = unix_autobind(sock)) != 0) > goto out; > > restart: > @@ -1063,8 +1063,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, > goto out; > addr_len = err; > > - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && > - (err = unix_autobind(sock)) != 0) > + if (u->addr == NULL && (err = unix_autobind(sock)) != 0) > goto out; > > timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); > @@ -1419,8 +1418,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, > goto out; > } > > - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr > - && (err = unix_autobind(sock)) != 0) > + if (u->addr == NULL && (err = unix_autobind(sock)) != 0) > goto out; > > err = -EMSGSIZE; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Tue, 28 Dec 2010 17:44:15 +0100 > Le samedi 25 décembre 2010 à 01:08 +0100, Jan Engelhardt a écrit : >> parent 67514fc40bbec857018cbc689d440282b75551db (v2.6.37-rc1-229-g67514fc) >> commit 973bdc63c6aba703dd7b62a6ec7ae4bab7847731 >> Author: Jan Engelhardt <jengelh@medozas.de> >> Date: Sat Dec 25 00:50:59 2010 +0100 >> >> net/unix: do not forget to autobind in standard case >> >> 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. This >> 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. >> > > 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 ? I definitely think that test is intentional. I'm not applying this without at least some basic research. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 = err; - if (test_bit(SOCK_PASSCRED, &sock->flags) && - !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) + if (unix_sk(sk)->addr == NULL && + (err = unix_autobind(sock)) != 0) goto out; restart: @@ -1063,8 +1063,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, goto out; addr_len = err; - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && - (err = unix_autobind(sock)) != 0) + if (u->addr == NULL && (err = unix_autobind(sock)) != 0) goto out; timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); @@ -1419,8 +1418,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, goto out; } - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr - && (err = unix_autobind(sock)) != 0) + if (u->addr == NULL && (err = unix_autobind(sock)) != 0) goto out; err = -EMSGSIZE;
parent 67514fc40bbec857018cbc689d440282b75551db (v2.6.37-rc1-229-g67514fc) commit 973bdc63c6aba703dd7b62a6ec7ae4bab7847731 Author: Jan Engelhardt <jengelh@medozas.de> Date: Sat Dec 25 00:50:59 2010 +0100 net/unix: do not forget to autobind in standard case 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. This 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. The shown test program outputs: getsockname gives 16 Received 2 bytes, and sk2_size is 16. Text: Hi reply text: World getsockname gives 2 Received 2 bytes, and sk2_size is 0. Text: Hi sendto fd1: Transport endpoint is not connected Aborted getsockname gives 8 Received 2 bytes, and sk2_size is 8. Text: Hi reply text: World ---8<--- //#define chosen_AF AF_INET union sockaddr_all { struct sockaddr_in in; struct sockaddr_un un; }; static inline size_t sock_size(unsigned int af) { if (af == AF_INET) return sizeof(struct sockaddr_in); if (af == AF_LOCAL) return sizeof(struct sockaddr_un); return 0; } int main(void) { union sockaddr_all sk1; union sockaddr_all sk2; int fd1, fd2; socklen_t sk2_size; char buf[64]; ssize_t ret; fd1 = socket(chosen_AF, SOCK_DGRAM, 0); if (fd1 < 0) { perror("socket fd1"); abort(); } memset(&sk1, 0, sizeof(sk1)); if (chosen_AF == AF_INET) { sk1.in.sin_family = chosen_AF; sk1.in.sin_port = htons(1234); } else if (chosen_AF == AF_LOCAL) { sk1.un.sun_family = chosen_AF; snprintf(sk1.un.sun_path, sizeof(sk1.un.sun_path), "/tmp/sk1"); unlink(sk1.un.sun_path); } if (bind(fd1, (void *)&sk1, sock_size(chosen_AF))) { perror("bind fd1"); abort(); } fd2 = socket(chosen_AF, SOCK_DGRAM, 0); if (fd2 < 0) { perror("socket"); abort(); } /* Cause implicit bind */ if (sendto(fd2, "Hi", 2, 0, (void *)&sk1, sock_size(chosen_AF)) < 0) { perror("sendto fd2"); abort(); } /* check if socket has been bound */ sk2_size = sock_size(chosen_AF); memset(&sk2, 0, sizeof(sk2)); if (getsockname(fd2, (void *)&sk2, &sk2_size) < 0) { perror("getsockname fd2"); abort(); } printf("getsockname gives %d\n", (int)sk2_size); /* But with recvfrom... */ memset(&sk2, 0, sizeof(sk2)); memset(buf, 0, sizeof(buf)); sk2_size = sock_size(chosen_AF); ret = recvfrom(fd1, buf, sizeof(buf), 0, (void *)&sk2, &sk2_size); if (ret < 0) { perror("recvfrom fd1"); abort(); } printf("Received %zd bytes, and sk2_size is %d. Text: %.*s\n", ret, (int)sk2_size, (int)ret, buf); ret = sendto(fd1, "World", 5, 0, (const void *)&sk2, sk2_size); if (ret < 0) { perror("sendto fd1"); abort(); } ret = recvfrom(fd2, buf, sizeof(buf), 0, NULL, 0); if (ret < 0) { perror("recvfrom fd2"); abort(); } printf("reply text: %.*s\n", (int)ret, buf); return 0; } --->8--- Signed-off-by: Jan Engelhardt <jengelh@medozas.de> --- net/unix/af_unix.c | 10 ++++------ 1 files changed, 4 insertions(+), 6 deletions(-)