From 30a584d944fbd599d4a8f470f75bf7af1a15b466 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 3 Aug 2006 16:38:49 -0700 Subject: [LLX]: SOCK_DGRAM interface fixes The datagram interface of LLC is broken in a couple of ways. These were discovered when trying to use it to build an out-of-kernel version of STP. First it didn't pass the source address of the received packet in recvfrom(). It needs to copy the source address of received LLC packets into the socket control block. At the same time fix a security issue because there was uninitialized data leakage. Every recvfrom call was just copying out old data. Second, LLC should not merge multiple packets in one receive call on datagram sockets. LLC should preserve packet boundaries on SOCK_DGRAM. This fix goes against the old historical comments about UNIX98 semantics but without this fix SOCK_DGRAM is broken and useless. So either ANK's interpretation was incorect or UNIX98 standard was wrong. Signed-off-by: Stephen Hemminger Acked-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/llc/af_llc.c | 20 ++++++++------------ net/llc/llc_sap.c | 4 ++-- 2 files changed, 10 insertions(+), 14 deletions(-) diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index d6cfe84d521b..2652ead96c64 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -784,24 +784,20 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock, copied += used; len -= used; - if (used + offset < skb->len) - continue; - if (!(flags & MSG_PEEK)) { sk_eat_skb(sk, skb, 0); *seq = 0; } + + /* For non stream protcols we get one packet per recvmsg call */ + if (sk->sk_type != SOCK_STREAM) + goto copy_uaddr; + + /* Partial read */ + if (used + offset < skb->len) + continue; } while (len > 0); - /* - * According to UNIX98, msg_name/msg_namelen are ignored - * on connected socket. -ANK - * But... af_llc still doesn't have separate sets of methods for - * SOCK_DGRAM and SOCK_STREAM :-( So we have to do this test, will - * eventually fix this tho :-) -acme - */ - if (sk->sk_type == SOCK_DGRAM) - goto copy_uaddr; out: release_sock(sk); return copied; diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c index 20c4eb5c1ac6..42eb0c3a9780 100644 --- a/net/llc/llc_sap.c +++ b/net/llc/llc_sap.c @@ -51,10 +51,10 @@ void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim) { struct sockaddr_llc *addr; - if (skb->sk->sk_type == SOCK_STREAM) /* See UNIX98 */ - return; /* save primitive for use by the user. */ addr = llc_ui_skb_cb(skb); + + memset(addr, 0, sizeof(*addr)); addr->sllc_family = sk->sk_family; addr->sllc_arphrd = skb->dev->type; addr->sllc_test = prim == LLC_TEST_PRIM; -- cgit v1.2.3-58-ga151