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| author | Mark Johnston <markj@FreeBSD.org> | 2021-09-14 13:02:05 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2021-09-14 13:02:05 +0000 |
| commit | e6c19aa94da4a799472f8b82f196ffc42d0dbdaf (patch) | |
| tree | f772bd0a35c9a88185286275b0057c41d5a72c98 | |
| parent | fa0463c384b652e1e962d5e8e70396e6a876f01b (diff) | |
| download | src-e6c19aa94da4a799472f8b82f196ffc42d0dbdaf.tar.gz src-e6c19aa94da4a799472f8b82f196ffc42d0dbdaf.zip | |
sctp: Allow blocking on I/O locks even with non-blocking sockets
There are two flags to request a non-blocking receive on a socket:
MSG_NBIO and MSG_DONTWAIT. They are handled a bit differently in that
soreceive_generic() and soreceive_stream() will block on the socket I/O
lock when MSG_NBIO is set, but not if MSG_DONTWAIT is set. In general,
MSG_NBIO seems to mean, "don't block if there is no data to receive" and
MSG_DONTWAIT means "don't go to sleep for any reason".
SCTP's soreceive implementation did not allow blocking on the I/O lock
if either flag is set, but this violates an assumption in
aio_process_sb(), which specifies MSG_NBIO but nonetheless
expects to make progress if data is available to read. Change
sctp_sorecvmsg() to block on the I/O lock only if MSG_DONTWAIT
is not set.
Reported by: syzbot+c7d22dbbb9aef509421d@syzkaller.appspotmail.com
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31915
| -rw-r--r-- | sys/netinet/sctputil.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/netinet/sctputil.c b/sys/netinet/sctputil.c index 09d486038b65..c6cdd3315704 100644 --- a/sys/netinet/sctputil.c +++ b/sys/netinet/sctputil.c @@ -5585,7 +5585,7 @@ sctp_sorecvmsg(struct socket *so, rwnd_req, block_allowed, so->so_rcv.sb_cc, (uint32_t)uio->uio_resid); } - error = SOCK_IO_RECV_LOCK(so, (block_allowed ? SBL_WAIT : 0)); + error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(in_flags)); if (error) { goto release_unlocked; } |