From 29322d0db98e5a84f5cc6a55655bee3dc4ffb5ab Mon Sep 17 00:00:00 2001 From: Jon Paul Maloy Date: Sat, 5 Jul 2014 13:44:13 -0400 Subject: [PATCH] tipc: fix bug in multicast/broadcast message reassembly Since commit 37e22164a8a3c39bdad45aa463b1e69a1fdf4110 ("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 Acked-by: Ying Xue Signed-off-by: David S. Miller --- net/tipc/msg.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/tipc/msg.c b/net/tipc/msg.c index 8be6e94a1ca9..0a37a472c29f 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -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; } -- GitLab