Date: Tue, 29 Apr 2025 00:47:55 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: c0c5d01e5374 - stable/14 - so_splice: Synchronize so_unsplice() with so_splice() Message-ID: <202504290047.53T0ltFP014377@gitrepo.freebsd.org>
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The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=c0c5d01e53745f97a1fa132d47c27a8c300ab4f8 commit c0c5d01e53745f97a1fa132d47c27a8c300ab4f8 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2025-04-15 00:55:00 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2025-04-29 00:44:04 +0000 so_splice: Synchronize so_unsplice() with so_splice() so_unsplice() assumed that if SB_SPLICED is set in the receive buffer of the first socket, then the splice is fully initialized. However, that's not true, and it's possible for so_unsplice() to race ahead of so_splice(). Modify so_unsplice() to simply bail if the splice state is embryonic. Reported by: syzkaller Reviewed by: gallatin Fixes: a1da7dc1cdad ("socket: Implement SO_SPLICE") MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D49814 (cherry picked from commit 992b18a9ec9f21cdf15b70b2f510fa2a69844385) --- sys/kern/uipc_socket.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c index fffb1d5b9af4..6468b3001b3e 100644 --- a/sys/kern/uipc_socket.c +++ b/sys/kern/uipc_socket.c @@ -1721,6 +1721,8 @@ so_splice(struct socket *so, struct socket *so2, struct splice *splice) /* * Transfer any data already present in the socket buffer. */ + KASSERT(sp->state == SPLICE_INIT, + ("so_splice: splice %p state %d", sp, sp->state)); sp->state = SPLICE_QUEUED; so_splice_xfer(sp); return (0); @@ -1749,8 +1751,19 @@ so_unsplice(struct socket *so, bool timeout) SOCK_UNLOCK(so); return (ENOTCONN); } - so->so_rcv.sb_flags &= ~SB_SPLICED; sp = so->so_splice; + mtx_lock(&sp->mtx); + if (sp->state == SPLICE_INIT) { + /* + * A splice is in the middle of being set up. + */ + mtx_unlock(&sp->mtx); + SOCK_RECVBUF_UNLOCK(so); + SOCK_UNLOCK(so); + return (ENOTCONN); + } + mtx_unlock(&sp->mtx); + so->so_rcv.sb_flags &= ~SB_SPLICED; so->so_splice = NULL; SOCK_RECVBUF_UNLOCK(so); SOCK_UNLOCK(so);
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