From: Qiujun Huang hqjagain@gmail.com
[ Upstream commit 5c3e82fe159622e46e91458c1a6509c321a62820 ]
We should iterate over the datamsgs to move all chunks(skbs) to newsk.
The following case cause the bug: for the trouble SKB, it was in outq->transmitted list
sctp_outq_sack sctp_check_transmitted SKB was moved to outq->sacked list then throw away the sack queue SKB was deleted from outq->sacked (but it was held by datamsg at sctp_datamsg_to_asoc So, sctp_wfree was not called here)
then migrate happened
sctp_for_each_tx_datachunk( sctp_clear_owner_w); sctp_assoc_migrate(); sctp_for_each_tx_datachunk( sctp_set_owner_w); SKB was not in the outq, and was not changed to newsk
finally
__sctp_outq_teardown sctp_chunk_put (for another skb) sctp_datamsg_put __kfree_skb(msg->frag_list) sctp_wfree (for SKB) SKB->sk was still oldsk (skb->sk != asoc->base.sk).
Reported-and-tested-by: syzbot+cea71eec5d6de256d54d@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang hqjagain@gmail.com Acked-by: Marcelo Ricardo Leitner mleitner@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/socket.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index ffd3262b7a41..58fe6556cdf5 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -147,29 +147,44 @@ static void sctp_clear_owner_w(struct sctp_chunk *chunk) skb_orphan(chunk->skb); }
+#define traverse_and_process() \ +do { \ + msg = chunk->msg; \ + if (msg == prev_msg) \ + continue; \ + list_for_each_entry(c, &msg->chunks, frag_list) { \ + if ((clear && asoc->base.sk == c->skb->sk) || \ + (!clear && asoc->base.sk != c->skb->sk)) \ + cb(c); \ + } \ + prev_msg = msg; \ +} while (0) + static void sctp_for_each_tx_datachunk(struct sctp_association *asoc, + bool clear, void (*cb)(struct sctp_chunk *))
{ + struct sctp_datamsg *msg, *prev_msg = NULL; struct sctp_outq *q = &asoc->outqueue; + struct sctp_chunk *chunk, *c; struct sctp_transport *t; - struct sctp_chunk *chunk;
list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) list_for_each_entry(chunk, &t->transmitted, transmitted_list) - cb(chunk); + traverse_and_process();
list_for_each_entry(chunk, &q->retransmit, transmitted_list) - cb(chunk); + traverse_and_process();
list_for_each_entry(chunk, &q->sacked, transmitted_list) - cb(chunk); + traverse_and_process();
list_for_each_entry(chunk, &q->abandoned, transmitted_list) - cb(chunk); + traverse_and_process();
list_for_each_entry(chunk, &q->out_chunk_list, list) - cb(chunk); + traverse_and_process(); }
static void sctp_for_each_rx_skb(struct sctp_association *asoc, struct sock *sk, @@ -9461,9 +9476,9 @@ static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, * paths won't try to lock it and then oldsk. */ lock_sock_nested(newsk, SINGLE_DEPTH_NESTING); - sctp_for_each_tx_datachunk(assoc, sctp_clear_owner_w); + sctp_for_each_tx_datachunk(assoc, true, sctp_clear_owner_w); sctp_assoc_migrate(assoc, newsk); - sctp_for_each_tx_datachunk(assoc, sctp_set_owner_w); + sctp_for_each_tx_datachunk(assoc, false, sctp_set_owner_w);
/* If the association on the newsk is already closed before accept() * is called, set RCV_SHUTDOWN flag.