The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ee4731179cb818570c8f708e77d238bf094d556c
commit ee4731179cb818570c8f708e77d238bf094d556c
Author: Mark Johnston <ma...@freebsd.org>
AuthorDate: 2021-09-08 03:20:21 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2021-09-08 15:41:19 +0000
sctp: Fix a lock order reversal in sctp_swap_inpcb_for_listen()
When port reuse is enabled in a one-to-one-style socket, sctp_listen()
may call sctp_swap_inpcb_for_listen() to move the PCB out of the "TCP
pool". In so doing it will drop the PCB lock, yielding an LOR since we
now hold several socket locks. Reorder sctp_listen() so that it
performs this operation before beginning the conversion to a listening
socket. Also modify sctp_swap_inpcb_for_listen() to return with PCB
write-locked, since that's what sctp_listen() expects now.
Reviewed by: tuexen
Fixes: bd4a39cc93d9 ("socket: Properly interlock when transitioning to a
listening socket")
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31879
---
sys/netinet/sctp_pcb.c | 5 ++---
sys/netinet/sctp_usrreq.c | 15 ++++++---------
2 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/sys/netinet/sctp_pcb.c b/sys/netinet/sctp_pcb.c
index cdecb9f4bc9c..ee5308ff6192 100644
--- a/sys/netinet/sctp_pcb.c
+++ b/sys/netinet/sctp_pcb.c
@@ -1846,6 +1846,7 @@ sctp_swap_inpcb_for_listen(struct sctp_inpcb *inp)
struct sctp_inpcb *tinp, *ninp;
SCTP_INP_INFO_WLOCK_ASSERT();
+ SCTP_INP_WLOCK_ASSERT(inp);
if (sctp_is_feature_off(inp, SCTP_PCB_FLAGS_PORTREUSE)) {
/* only works with port reuse on */
@@ -1854,7 +1855,7 @@ sctp_swap_inpcb_for_listen(struct sctp_inpcb *inp)
if ((inp->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL) == 0) {
return (0);
}
- SCTP_INP_RUNLOCK(inp);
+ SCTP_INP_WUNLOCK(inp);
head =
&SCTP_BASE_INFO(sctp_ephash)[SCTP_PCBHASH_ALLADDR(inp->sctp_lport,
SCTP_BASE_INFO(hashmark))];
/* Kick out all non-listeners to the TCP hash */
@@ -1884,8 +1885,6 @@ sctp_swap_inpcb_for_listen(struct sctp_inpcb *inp)
inp->sctp_flags &= ~SCTP_PCB_FLAGS_IN_TCPPOOL;
head =
&SCTP_BASE_INFO(sctp_ephash)[SCTP_PCBHASH_ALLADDR(inp->sctp_lport,
SCTP_BASE_INFO(hashmark))];
LIST_INSERT_HEAD(head, inp, sctp_hash);
- SCTP_INP_WUNLOCK(inp);
- SCTP_INP_RLOCK(inp);
return (0);
}
diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c
index 7079cdf7c403..309cce10fe9b 100644
--- a/sys/netinet/sctp_usrreq.c
+++ b/sys/netinet/sctp_usrreq.c
@@ -7208,12 +7208,6 @@ sctp_listen(struct socket *so, int backlog, struct
thread *p)
sctp_log_lock(inp, (struct sctp_tcb *)NULL, SCTP_LOG_LOCK_SOCK);
}
#endif
- SOCK_LOCK(so);
- error = solisten_proto_check(so);
- if (error) {
- SOCK_UNLOCK(so);
- goto out;
- }
if ((sctp_is_feature_on(inp, SCTP_PCB_FLAGS_PORTREUSE)) &&
(inp->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) {
/*
@@ -7223,14 +7217,17 @@ sctp_listen(struct socket *so, int backlog, struct
thread *p)
* move the guy that was listener to the TCP Pool.
*/
if (sctp_swap_inpcb_for_listen(inp)) {
- SOCK_UNLOCK(so);
- solisten_proto_abort(so);
error = EADDRINUSE;
SCTP_LTRACE_ERR_RET(inp, NULL, NULL,
SCTP_FROM_SCTP_USRREQ, error);
goto out;
}
}
-
+ SOCK_LOCK(so);
+ error = solisten_proto_check(so);
+ if (error) {
+ SOCK_UNLOCK(so);
+ goto out;
+ }
if ((inp->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) &&
(inp->sctp_flags & SCTP_PCB_FLAGS_CONNECTED)) {
SOCK_UNLOCK(so);
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