tipc: fix bug in multicast/broadcast message reassembly (29322d0d) · Commits · 戴 / test

Since commit ("tipc: rename and move message reassembly function") reassembly of long broadcast messages has been broken. This is because we test for a non-NULL return value of the *buf parameter as criteria for succesful reassembly. However, this parameter is left defined even after reception of the first fragment, when reassebly is still incomplete. This leads to a kernel crash as soon as a the first fragment of a long broadcast message is received. We fix this with this commit, by implementing a stricter behavior of the function and its return values. This commit should be applied to both net and net-next. Signed-off-by:

Jon Maloy <jon.maloy@ericsson.com> Acked-by:

Ying Xue <ying.xue@windriver.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/tipc/msg.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -101,9 +101,11 @@ int tipc_msg_build(struct tipc_msg hdr, struct iovec const msg_sect,
		}

		/* tipc_buf_append(): Append a buffer to the fragment list of another buffer
		* Let first buffer become head buffer
		* Returns 1 and sets *buf to headbuf if chain is complete, otherwise 0
		* Leaves headbuf pointer at NULL if failure
		* @*headbuf: in: NULL for first frag, otherwise value returned from prev call
		* out: set when successful non-complete reassembly, otherwise NULL
		* @*buf: in: the buffer to append. Always defined
		* out: head buf after sucessful complete reassembly, otherwise NULL
		* Returns 1 when reassembly complete, otherwise 0
		*/
		int tipc_buf_append(struct sk_buff headbuf, struct sk_buff buf)
		{
		@@ -122,6 +124,7 @@ int tipc_buf_append(struct sk_buff headbuf, struct sk_buff buf)
		goto out_free;
		head = *headbuf = frag;
		skb_frag_list_init(head);
		*buf = NULL;
		return 0;
		}
		if (!head)
		@@ -150,5 +153,7 @@ int tipc_buf_append(struct sk_buff headbuf, struct sk_buff buf)
		out_free:
		pr_warn_ratelimited("Unable to build fragment list\n");
		kfree_skb(*buf);
		kfree_skb(*headbuf);
		buf = headbuf = NULL;
		return 0;
		}

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