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authorJon Paul Maloy <jon.maloy@ericsson.com>2015-03-13 16:08:06 -0400
committerDavid S. Miller <davem@davemloft.net>2015-03-14 14:38:32 -0400
commitcf2157f88a5abf1a64b8c51a737a35e918dc67e5 (patch)
tree8896dd853ffa7676faeba4423d494a17fba67db1 /net/tipc/msg.c
parent7764d6e83d2c3b50d9282f12144ebb10418c056e (diff)
downloadlwn-cf2157f88a5abf1a64b8c51a737a35e918dc67e5.tar.gz
lwn-cf2157f88a5abf1a64b8c51a737a35e918dc67e5.zip
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 <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/msg.c')
-rw-r--r--net/tipc/msg.c44
1 files changed, 43 insertions, 1 deletions
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