From: NeilBrown Date: Fri, 5 Feb 2021 00:36:30 +0000 (+1100) Subject: net: fix iteration for sctp transport seq_files X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=af8085f3a4712c57d0dd415ad543bac85780375c;p=linux.git net: fix iteration for sctp transport seq_files The sctp transport seq_file iterators take a reference to the transport in the ->start and ->next functions and releases the reference in the ->show function. The preferred handling for such resources is to release them in the subsequent ->next or ->stop function call. Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") there is no guarantee that ->show will be called after ->next, so this function can now leak references. So move the sctp_transport_put() call to ->next and ->stop. Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Reported-by: Xin Long Signed-off-by: NeilBrown Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski --- diff --git a/net/sctp/proc.c b/net/sctp/proc.c index f7da88ae20a57..982a87b3e11f8 100644 --- a/net/sctp/proc.c +++ b/net/sctp/proc.c @@ -215,6 +215,12 @@ static void sctp_transport_seq_stop(struct seq_file *seq, void *v) { struct sctp_ht_iter *iter = seq->private; + if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + sctp_transport_walk_stop(&iter->hti); } @@ -222,6 +228,12 @@ static void *sctp_transport_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct sctp_ht_iter *iter = seq->private; + if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + ++*pos; return sctp_transport_get_next(seq_file_net(seq), &iter->hti); @@ -277,8 +289,6 @@ static int sctp_assocs_seq_show(struct seq_file *seq, void *v) sk->sk_rcvbuf); seq_printf(seq, "\n"); - sctp_transport_put(transport); - return 0; } @@ -354,8 +364,6 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v) seq_printf(seq, "\n"); } - sctp_transport_put(transport); - return 0; }