Date: Wed, 8 Sep 2021 15:41:25 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: ee4731179cb8 - main - sctp: Fix a lock order reversal in sctp_swap_inpcb_for_listen() Message-ID: <202109081541.188FfP0C004150@gitrepo.freebsd.org>
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The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=ee4731179cb818570c8f708e77d238bf094d556c commit ee4731179cb818570c8f708e77d238bf094d556c Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2021-09-08 03:20:21 +0000 Commit: Mark Johnston <markj@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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