From cf2157f88a5abf1a64b8c51a737a35e918dc67e5 Mon Sep 17 00:00:00 2001 From: Jon Paul Maloy Date: Fri, 13 Mar 2015 16:08:06 -0400 Subject: tipc: move message validation function to msg.c The function link_buf_validate() is in reality re-entrant and context independent, and will in later commits be called from several locations. Therefore, we move it to msg.c, make it outline and rename the it to tipc_msg_validate(). We also redesign the function to make proper use of pskb_may_pull() Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/msg.c | 44 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) (limited to 'net/tipc/msg.c') diff --git a/net/tipc/msg.c b/net/tipc/msg.c index b6eb90cd3ef7..4a64caf6fa20 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -1,7 +1,7 @@ /* * net/tipc/msg.c: TIPC message header routines * - * Copyright (c) 2000-2006, 2014, Ericsson AB + * Copyright (c) 2000-2006, 2014-2015, Ericsson AB * Copyright (c) 2005, 2010-2011, Wind River Systems * All rights reserved. * @@ -181,6 +181,48 @@ err: return 0; } +/* tipc_msg_validate - validate basic format of received message + * + * This routine ensures a TIPC message has an acceptable header, and at least + * as much data as the header indicates it should. The routine also ensures + * that the entire message header is stored in the main fragment of the message + * buffer, to simplify future access to message header fields. + * + * Note: Having extra info present in the message header or data areas is OK. + * TIPC will ignore the excess, under the assumption that it is optional info + * introduced by a later release of the protocol. + */ +bool tipc_msg_validate(struct sk_buff *skb) +{ + struct tipc_msg *msg; + int msz, hsz; + + if (unlikely(TIPC_SKB_CB(skb)->validated)) + return true; + if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE))) + return false; + + hsz = msg_hdr_sz(buf_msg(skb)); + if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE)) + return false; + if (unlikely(!pskb_may_pull(skb, hsz))) + return false; + + msg = buf_msg(skb); + if (unlikely(msg_version(msg) != TIPC_VERSION)) + return false; + + msz = msg_size(msg); + if (unlikely(msz < hsz)) + return false; + if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE)) + return false; + if (unlikely(skb->len < msz)) + return false; + + TIPC_SKB_CB(skb)->validated = true; + return true; +} /** * tipc_msg_build - create buffer chain containing specified header and data -- cgit v1.2.3