/* * Copyright 2004 Robert N. M. Watson * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_mac.h" #include #include #include #include /* XXX must be before */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static uma_zone_t unp_zone; static unp_gen_t unp_gencnt; static u_int unp_count; static struct unp_head unp_shead, unp_dhead; /* * Unix communications domain. * * TODO: * SEQPACKET, RDM * rethink name space problems * need a proper out-of-band * lock pushdown */ static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; static ino_t unp_ino; /* prototype for fake inode numbers */ /* * Currently, UNIX domain sockets are protected by a single subsystem lock, * which covers global data structures and variables, the contents of each * per-socket unpcb structure, and the so_pcb field in sockets attached to * the UNIX domain. This provides for a moderate degree of paralellism, as * receive operations on UNIX domain sockets do not need to acquire the * subsystem lock. Finer grained locking to permit send() without acquiring * a global lock would be a logical next step. * * The UNIX domain socket lock preceds all socket layer locks, including the * socket lock and socket buffer lock, permitting UNIX domain socket code to * call into socket support routines without releasing its locks. * * Some caution is required in areas where the UNIX domain socket code enters * VFS in order to create or find rendezvous points. This results in * dropping of the UNIX domain socket subsystem lock, acquisition of the * Giant lock, and potential sleeping. This increases the chances of races, * and exposes weaknesses in the socket->protocol API by offering poor * failure modes. */ static struct mtx unp_mtx; #define UNP_LOCK_INIT() \ mtx_init(&unp_mtx, "unp", NULL, MTX_DEF) #define UNP_LOCK() mtx_lock(&unp_mtx) #define UNP_UNLOCK() mtx_unlock(&unp_mtx) #define UNP_LOCK_ASSERT() mtx_assert(&unp_mtx, MA_OWNED) #define UNP_UNLOCK_ASSERT() mtx_assert(&unp_mtx, MA_NOTOWNED) static int unp_attach(struct socket *); static void unp_detach(struct unpcb *); static int unp_bind(struct unpcb *,struct sockaddr *, struct thread *); static int unp_connect(struct socket *,struct sockaddr *, struct thread *); static int unp_connect2(struct socket *so, struct socket *so2); static void unp_disconnect(struct unpcb *); static void unp_shutdown(struct unpcb *); static void unp_drop(struct unpcb *, int); static void unp_gc(void); static void unp_scan(struct mbuf *, void (*)(struct file *)); static void unp_mark(struct file *); static void unp_discard(struct file *); static void unp_freerights(struct file **, int); static int unp_internalize(struct mbuf **, struct thread *); static int unp_listen(struct unpcb *, struct thread *); static int uipc_abort(struct socket *so) { struct unpcb *unp; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } unp_drop(unp, ECONNABORTED); unp_detach(unp); UNP_UNLOCK_ASSERT(); SOCK_LOCK(so); sotryfree(so); return (0); } static int uipc_accept(struct socket *so, struct sockaddr **nam) { struct unpcb *unp; const struct sockaddr *sa; /* * Pass back name of connected socket, * if it was bound and we are still connected * (our peer may have closed already!). */ *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); free(*nam, M_SONAME); *nam = NULL; return (EINVAL); } if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL) sa = (struct sockaddr *) unp->unp_conn->unp_addr; else sa = &sun_noname; bcopy(sa, *nam, sa->sa_len); UNP_UNLOCK(); return (0); } static int uipc_attach(struct socket *so, int proto, struct thread *td) { struct unpcb *unp = sotounpcb(so); if (unp != NULL) return (EISCONN); return (unp_attach(so)); } static int uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) { struct unpcb *unp; int error; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } error = unp_bind(unp, nam, td); UNP_UNLOCK(); return (error); } static int uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) { struct unpcb *unp; int error; KASSERT(td == curthread, ("uipc_connect: td != curthread")); UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } error = unp_connect(so, nam, td); UNP_UNLOCK(); return (error); } int uipc_connect2(struct socket *so1, struct socket *so2) { struct unpcb *unp; int error; UNP_LOCK(); unp = sotounpcb(so1); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } error = unp_connect2(so1, so2); UNP_UNLOCK(); return (error); } /* control is EOPNOTSUPP */ static int uipc_detach(struct socket *so) { struct unpcb *unp; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } unp_detach(unp); UNP_UNLOCK_ASSERT(); return (0); } static int uipc_disconnect(struct socket *so) { struct unpcb *unp; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } unp_disconnect(unp); UNP_UNLOCK(); return (0); } static int uipc_listen(struct socket *so, struct thread *td) { struct unpcb *unp; int error; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL || unp->unp_vnode == NULL) { UNP_UNLOCK(); return (EINVAL); } error = unp_listen(unp, td); UNP_UNLOCK(); return (error); } static int uipc_peeraddr(struct socket *so, struct sockaddr **nam) { struct unpcb *unp; const struct sockaddr *sa; *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); free(*nam, M_SONAME); *nam = NULL; return (EINVAL); } if (unp->unp_conn != NULL && unp->unp_conn->unp_addr!= NULL) sa = (struct sockaddr *) unp->unp_conn->unp_addr; else { /* * XXX: It seems that this test always fails even when * connection is established. So, this else clause is * added as workaround to return PF_LOCAL sockaddr. */ sa = &sun_noname; } bcopy(sa, *nam, sa->sa_len); UNP_UNLOCK(); return (0); } static int uipc_rcvd(struct socket *so, int flags) { struct unpcb *unp; struct socket *so2; u_long newhiwat; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } switch (so->so_type) { case SOCK_DGRAM: panic("uipc_rcvd DGRAM?"); /*NOTREACHED*/ case SOCK_STREAM: if (unp->unp_conn == NULL) break; so2 = unp->unp_conn->unp_socket; SOCKBUF_LOCK(&so2->so_snd); SOCKBUF_LOCK(&so->so_rcv); /* * Adjust backpressure on sender * and wakeup any waiting to write. */ so2->so_snd.sb_mbmax += unp->unp_mbcnt - so->so_rcv.sb_mbcnt; unp->unp_mbcnt = so->so_rcv.sb_mbcnt; newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - so->so_rcv.sb_cc; (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, newhiwat, RLIM_INFINITY); unp->unp_cc = so->so_rcv.sb_cc; SOCKBUF_UNLOCK(&so->so_rcv); sowwakeup_locked(so2); break; default: panic("uipc_rcvd unknown socktype"); } UNP_UNLOCK(); return (0); } /* pru_rcvoob is EOPNOTSUPP */ static int uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, struct mbuf *control, struct thread *td) { int error = 0; struct unpcb *unp; struct socket *so2; u_long newhiwat; unp = sotounpcb(so); if (unp == NULL) { error = EINVAL; goto release; } if (flags & PRUS_OOB) { error = EOPNOTSUPP; goto release; } if (control != NULL && (error = unp_internalize(&control, td))) goto release; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); error = EINVAL; goto dispose_release; } switch (so->so_type) { case SOCK_DGRAM: { const struct sockaddr *from; if (nam != NULL) { if (unp->unp_conn != NULL) { error = EISCONN; break; } error = unp_connect(so, nam, td); if (error) break; } else { if (unp->unp_conn == NULL) { error = ENOTCONN; break; } } so2 = unp->unp_conn->unp_socket; if (unp->unp_addr != NULL) from = (struct sockaddr *)unp->unp_addr; else from = &sun_noname; SOCKBUF_LOCK(&so2->so_rcv); if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { sorwakeup_locked(so2); m = NULL; control = NULL; } else { SOCKBUF_UNLOCK(&so2->so_rcv); error = ENOBUFS; } if (nam != NULL) unp_disconnect(unp); break; } case SOCK_STREAM: /* Connect if not connected yet. */ /* * Note: A better implementation would complain * if not equal to the peer's address. */ if ((so->so_state & SS_ISCONNECTED) == 0) { if (nam != NULL) { error = unp_connect(so, nam, td); if (error) break; /* XXX */ } else { error = ENOTCONN; break; } } if (so->so_snd.sb_state & SBS_CANTSENDMORE) { error = EPIPE; break; } if (unp->unp_conn == NULL) panic("uipc_send connected but no connection?"); so2 = unp->unp_conn->unp_socket; SOCKBUF_LOCK(&so2->so_rcv); /* * Send to paired receive port, and then reduce * send buffer hiwater marks to maintain backpressure. * Wake up readers. */ if (control != NULL) { if (sbappendcontrol_locked(&so2->so_rcv, m, control)) control = NULL; } else { sbappend_locked(&so2->so_rcv, m); } so->so_snd.sb_mbmax -= so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt; unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt; newhiwat = so->so_snd.sb_hiwat - (so2->so_rcv.sb_cc - unp->unp_conn->unp_cc); (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, newhiwat, RLIM_INFINITY); unp->unp_conn->unp_cc = so2->so_rcv.sb_cc; sorwakeup_locked(so2); m = NULL; break; default: panic("uipc_send unknown socktype"); } /* * SEND_EOF is equivalent to a SEND followed by * a SHUTDOWN. */ if (flags & PRUS_EOF) { socantsendmore(so); unp_shutdown(unp); } UNP_UNLOCK(); dispose_release: if (control != NULL && error != 0) unp_dispose(control); release: if (control != NULL) m_freem(control); if (m != NULL) m_freem(m); return (error); } static int uipc_sense(struct socket *so, struct stat *sb) { struct unpcb *unp; struct socket *so2; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } sb->st_blksize = so->so_snd.sb_hiwat; if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { so2 = unp->unp_conn->unp_socket; sb->st_blksize += so2->so_rcv.sb_cc; } sb->st_dev = NODEV; if (unp->unp_ino == 0) unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; sb->st_ino = unp->unp_ino; UNP_UNLOCK(); return (0); } static int uipc_shutdown(struct socket *so) { struct unpcb *unp; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); return (EINVAL); } socantsendmore(so); unp_shutdown(unp); UNP_UNLOCK(); return (0); } static int uipc_sockaddr(struct socket *so, struct sockaddr **nam) { struct unpcb *unp; const struct sockaddr *sa; *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); free(*nam, M_SONAME); *nam = NULL; return (EINVAL); } if (unp->unp_addr != NULL) sa = (struct sockaddr *) unp->unp_addr; else sa = &sun_noname; bcopy(sa, *nam, sa->sa_len); UNP_UNLOCK(); return (0); } struct pr_usrreqs uipc_usrreqs = { uipc_abort, uipc_accept, uipc_attach, uipc_bind, uipc_connect, uipc_connect2, pru_control_notsupp, uipc_detach, uipc_disconnect, uipc_listen, uipc_peeraddr, uipc_rcvd, pru_rcvoob_notsupp, uipc_send, uipc_sense, uipc_shutdown, uipc_sockaddr, sosend, soreceive, sopoll, pru_sosetlabel_null }; int uipc_ctloutput(so, sopt) struct socket *so; struct sockopt *sopt; { struct unpcb *unp; struct xucred xu; int error; switch (sopt->sopt_dir) { case SOPT_GET: switch (sopt->sopt_name) { case LOCAL_PEERCRED: error = 0; UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { UNP_UNLOCK(); error = EINVAL; break; } if (unp->unp_flags & UNP_HAVEPC) xu = unp->unp_peercred; else { if (so->so_type == SOCK_STREAM) error = ENOTCONN; else error = EINVAL; } UNP_UNLOCK(); if (error == 0) error = sooptcopyout(sopt, &xu, sizeof(xu)); break; default: error = EOPNOTSUPP; break; } break; case SOPT_SET: default: error = EOPNOTSUPP; break; } return (error); } /* * Both send and receive buffers are allocated PIPSIZ bytes of buffering * for stream sockets, although the total for sender and receiver is * actually only PIPSIZ. * Datagram sockets really use the sendspace as the maximum datagram size, * and don't really want to reserve the sendspace. Their recvspace should * be large enough for at least one max-size datagram plus address. */ #ifndef PIPSIZ #define PIPSIZ 8192 #endif static u_long unpst_sendspace = PIPSIZ; static u_long unpst_recvspace = PIPSIZ; static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ static u_long unpdg_recvspace = 4*1024; static int unp_rights; /* file descriptors in flight */ SYSCTL_DECL(_net_local_stream); SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, &unpst_sendspace, 0, ""); SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, &unpst_recvspace, 0, ""); SYSCTL_DECL(_net_local_dgram); SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, &unpdg_sendspace, 0, ""); SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, &unpdg_recvspace, 0, ""); SYSCTL_DECL(_net_local); SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); static int unp_attach(so) struct socket *so; { register struct unpcb *unp; int error; if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { switch (so->so_type) { case SOCK_STREAM: error = soreserve(so, unpst_sendspace, unpst_recvspace); break; case SOCK_DGRAM: error = soreserve(so, unpdg_sendspace, unpdg_recvspace); break; default: panic("unp_attach"); } if (error) return (error); } unp = uma_zalloc(unp_zone, M_WAITOK); if (unp == NULL) return (ENOBUFS); bzero(unp, sizeof *unp); LIST_INIT(&unp->unp_refs); unp->unp_socket = so; UNP_LOCK(); unp->unp_gencnt = ++unp_gencnt; unp_count++; LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead : &unp_shead, unp, unp_link); so->so_pcb = unp; UNP_UNLOCK(); return (0); } static void unp_detach(unp) register struct unpcb *unp; { struct vnode *vp; UNP_LOCK_ASSERT(); LIST_REMOVE(unp, unp_link); unp->unp_gencnt = ++unp_gencnt; --unp_count; if ((vp = unp->unp_vnode) != NULL) { /* * XXXRW: should v_socket be frobbed only while holding * Giant? */ unp->unp_vnode->v_socket = NULL; unp->unp_vnode = NULL; } if (unp->unp_conn != NULL) unp_disconnect(unp); while (!LIST_EMPTY(&unp->unp_refs)) { struct unpcb *ref = LIST_FIRST(&unp->unp_refs); unp_drop(ref, ECONNRESET); } soisdisconnected(unp->unp_socket); unp->unp_socket->so_pcb = NULL; if (unp_rights) { /* * Normally the receive buffer is flushed later, * in sofree, but if our receive buffer holds references * to descriptors that are now garbage, we will dispose * of those descriptor references after the garbage collector * gets them (resulting in a "panic: closef: count < 0"). */ sorflush(unp->unp_socket); unp_gc(); } UNP_UNLOCK(); if (unp->unp_addr != NULL) FREE(unp->unp_addr, M_SONAME); uma_zfree(unp_zone, unp); if (vp) { mtx_lock(&Giant); vrele(vp); mtx_unlock(&Giant); } } static int unp_bind(unp, nam, td) struct unpcb *unp; struct sockaddr *nam; struct thread *td; { struct sockaddr_un *soun = (struct sockaddr_un *)nam; struct vnode *vp; struct mount *mp; struct vattr vattr; int error, namelen; struct nameidata nd; char *buf; UNP_LOCK_ASSERT(); /* * XXXRW: This test-and-set of unp_vnode is non-atomic; the * unlocked read here is fine, but the value of unp_vnode needs * to be tested again after we do all the lookups to see if the * pcb is still unbound? */ if (unp->unp_vnode != NULL) return (EINVAL); namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); if (namelen <= 0) return (EINVAL); UNP_UNLOCK(); buf = malloc(namelen + 1, M_TEMP, M_WAITOK); strlcpy(buf, soun->sun_path, namelen + 1); mtx_lock(&Giant); restart: mtx_assert(&Giant, MA_OWNED); NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, buf, td); /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ error = namei(&nd); if (error) goto done; vp = nd.ni_vp; if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { NDFREE(&nd, NDF_ONLY_PNBUF); if (nd.ni_dvp == vp) vrele(nd.ni_dvp); else vput(nd.ni_dvp); if (vp != NULL) { vrele(vp); error = EADDRINUSE; goto done; } error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); if (error) goto done; goto restart; } VATTR_NULL(&vattr); vattr.va_type = VSOCK; vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); #ifdef MAC error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, &vattr); #endif if (error == 0) { VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); } NDFREE(&nd, NDF_ONLY_PNBUF); vput(nd.ni_dvp); if (error) goto done; vp = nd.ni_vp; ASSERT_VOP_LOCKED(vp, "unp_bind"); soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); UNP_LOCK(); vp->v_socket = unp->unp_socket; unp->unp_vnode = vp; unp->unp_addr = soun; UNP_UNLOCK(); VOP_UNLOCK(vp, 0, td); vn_finished_write(mp); done: mtx_unlock(&Giant); free(buf, M_TEMP); UNP_LOCK(); return (error); } static int unp_connect(so, nam, td) struct socket *so; struct sockaddr *nam; struct thread *td; { register struct sockaddr_un *soun = (struct sockaddr_un *)nam; register struct vnode *vp; register struct socket *so2, *so3; struct unpcb *unp, *unp2, *unp3; int error, len; struct nameidata nd; char buf[SOCK_MAXADDRLEN]; struct sockaddr *sa; UNP_LOCK_ASSERT(); unp = sotounpcb(so); len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); if (len <= 0) return (EINVAL); strlcpy(buf, soun->sun_path, len + 1); UNP_UNLOCK(); sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); mtx_lock(&Giant); NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); error = namei(&nd); if (error) vp = NULL; else vp = nd.ni_vp; ASSERT_VOP_LOCKED(vp, "unp_connect"); NDFREE(&nd, NDF_ONLY_PNBUF); if (error) goto bad; if (vp->v_type != VSOCK) { error = ENOTSOCK; goto bad; } error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); if (error) goto bad; mtx_unlock(&Giant); UNP_LOCK(); unp = sotounpcb(so); if (unp == NULL) { /* * XXXRW: Temporary debugging printf. */ printf("unp_connect(): lost race to another thread\n"); error = EINVAL; goto bad2; } so2 = vp->v_socket; if (so2 == NULL) { error = ECONNREFUSED; goto bad2; } if (so->so_type != so2->so_type) { error = EPROTOTYPE; goto bad2; } if (so->so_proto->pr_flags & PR_CONNREQUIRED) { if (so2->so_options & SO_ACCEPTCONN) { /* * NB: drop locks here so unp_attach is entered * w/o locks; this avoids a recursive lock * of the head and holding sleep locks across * a (potentially) blocking malloc. */ UNP_UNLOCK(); so3 = sonewconn(so2, 0); UNP_LOCK(); } else so3 = NULL; if (so3 == NULL) { error = ECONNREFUSED; goto bad2; } unp = sotounpcb(so); unp2 = sotounpcb(so2); unp3 = sotounpcb(so3); if (unp2->unp_addr != NULL) { bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); unp3->unp_addr = (struct sockaddr_un *) sa; sa = NULL; } /* * unp_peercred management: * * The connecter's (client's) credentials are copied * from its process structure at the time of connect() * (which is now). */ cru2x(td->td_ucred, &unp3->unp_peercred); unp3->unp_flags |= UNP_HAVEPC; /* * The receiver's (server's) credentials are copied * from the unp_peercred member of socket on which the * former called listen(); unp_listen() cached that * process's credentials at that time so we can use * them now. */ KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, ("unp_connect: listener without cached peercred")); memcpy(&unp->unp_peercred, &unp2->unp_peercred, sizeof(unp->unp_peercred)); unp->unp_flags |= UNP_HAVEPC; #ifdef MAC SOCK_LOCK(so); mac_set_socket_peer_from_socket(so, so3); mac_set_socket_peer_from_socket(so3, so); SOCK_UNLOCK(so); #endif so2 = so3; } error = unp_connect2(so, so2); bad2: UNP_UNLOCK(); mtx_lock(&Giant); bad: mtx_assert(&Giant, MA_OWNED); if (vp != NULL) vput(vp); mtx_unlock(&Giant); free(sa, M_SONAME); UNP_LOCK(); return (error); } static int unp_connect2(so, so2) register struct socket *so; register struct socket *so2; { register struct unpcb *unp = sotounpcb(so); register struct unpcb *unp2; UNP_LOCK_ASSERT(); if (so2->so_type != so->so_type) return (EPROTOTYPE); unp2 = sotounpcb(so2); unp->unp_conn = unp2; switch (so->so_type) { case SOCK_DGRAM: LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); soisconnected(so); break; case SOCK_STREAM: unp2->unp_conn = unp; soisconnected(so); soisconnected(so2); break; default: panic("unp_connect2"); } return (0); } static void unp_disconnect(unp) struct unpcb *unp; { register struct unpcb *unp2 = unp->unp_conn; struct socket *so; UNP_LOCK_ASSERT(); if (unp2 == NULL) return; unp->unp_conn = NULL; switch (unp->unp_socket->so_type) { case SOCK_DGRAM: LIST_REMOVE(unp, unp_reflink); so = unp->unp_socket; SOCK_LOCK(so); so->so_state &= ~SS_ISCONNECTED; SOCK_UNLOCK(so); break; case SOCK_STREAM: soisdisconnected(unp->unp_socket); unp2->unp_conn = NULL; soisdisconnected(unp2->unp_socket); break; } } #ifdef notdef void unp_abort(unp) struct unpcb *unp; { unp_detach(unp); UNP_UNLOCK_ASSERT(); } #endif /* * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed * by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers * are safe to reference. It first scans the list of struct unpcb's to * generate a pointer list, then it rescans its list one entry at a time to * externalize and copyout. It checks the generation number to see if a * struct unpcb has been reused, and will skip it if so. */ static int unp_pcblist(SYSCTL_HANDLER_ARGS) { int error, i, n; struct unpcb *unp, **unp_list; unp_gen_t gencnt; struct xunpgen *xug; struct unp_head *head; struct xunpcb *xu; head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); /* * The process of preparing the PCB list is too time-consuming and * resource-intensive to repeat twice on every request. */ if (req->oldptr == NULL) { n = unp_count; req->oldidx = 2 * (sizeof *xug) + (n + n/8) * sizeof(struct xunpcb); return (0); } if (req->newptr != NULL) return (EPERM); /* * OK, now we're committed to doing something. */ xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); UNP_LOCK(); gencnt = unp_gencnt; n = unp_count; UNP_UNLOCK(); xug->xug_len = sizeof *xug; xug->xug_count = n; xug->xug_gen = gencnt; xug->xug_sogen = so_gencnt; error = SYSCTL_OUT(req, xug, sizeof *xug); if (error) { free(xug, M_TEMP); return (error); } unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); UNP_LOCK(); for (unp = LIST_FIRST(head), i = 0; unp && i < n; unp = LIST_NEXT(unp, unp_link)) { if (unp->unp_gencnt <= gencnt) { if (cr_cansee(req->td->td_ucred, unp->unp_socket->so_cred)) continue; unp_list[i++] = unp; } } UNP_UNLOCK(); n = i; /* in case we lost some during malloc */ error = 0; xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK); for (i = 0; i < n; i++) { unp = unp_list[i]; if (unp->unp_gencnt <= gencnt) { xu->xu_len = sizeof *xu; xu->xu_unpp = unp; /* * XXX - need more locking here to protect against * connect/disconnect races for SMP. */ if (unp->unp_addr != NULL) bcopy(unp->unp_addr, &xu->xu_addr, unp->unp_addr->sun_len); if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL) bcopy(unp->unp_conn->unp_addr, &xu->xu_caddr, unp->unp_conn->unp_addr->sun_len); bcopy(unp, &xu->xu_unp, sizeof *unp); sotoxsocket(unp->unp_socket, &xu->xu_socket); error = SYSCTL_OUT(req, xu, sizeof *xu); } } free(xu, M_TEMP); if (!error) { /* * Give the user an updated idea of our state. * If the generation differs from what we told * her before, she knows that something happened * while we were processing this request, and it * might be necessary to retry. */ xug->xug_gen = unp_gencnt; xug->xug_sogen = so_gencnt; xug->xug_count = unp_count; error = SYSCTL_OUT(req, xug, sizeof *xug); } free(unp_list, M_TEMP); free(xug, M_TEMP); return (error); } SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", "List of active local datagram sockets"); SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", "List of active local stream sockets"); static void unp_shutdown(unp) struct unpcb *unp; { struct socket *so; UNP_LOCK_ASSERT(); if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && (so = unp->unp_conn->unp_socket)) socantrcvmore(so); } static void unp_drop(unp, errno) struct unpcb *unp; int errno; { struct socket *so = unp->unp_socket; UNP_LOCK_ASSERT(); so->so_error = errno; unp_disconnect(unp); } #ifdef notdef void unp_drain() { } #endif static void unp_freerights(rp, fdcount) struct file **rp; int fdcount; { int i; struct file *fp; for (i = 0; i < fdcount; i++) { fp = *rp; /* * zero the pointer before calling * unp_discard since it may end up * in unp_gc().. */ *rp++ = 0; unp_discard(fp); } } int unp_externalize(control, controlp) struct mbuf *control, **controlp; { struct thread *td = curthread; /* XXX */ struct cmsghdr *cm = mtod(control, struct cmsghdr *); int i; int *fdp; struct file **rp; struct file *fp; void *data; socklen_t clen = control->m_len, datalen; int error, newfds; int f; u_int newlen; UNP_UNLOCK_ASSERT(); error = 0; if (controlp != NULL) /* controlp == NULL => free control messages */ *controlp = NULL; while (cm != NULL) { if (sizeof(*cm) > clen || cm->cmsg_len > clen) { error = EINVAL; break; } data = CMSG_DATA(cm); datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; if (cm->cmsg_level == SOL_SOCKET && cm->cmsg_type == SCM_RIGHTS) { newfds = datalen / sizeof(struct file *); rp = data; /* If we're not outputting the descriptors free them. */ if (error || controlp == NULL) { unp_freerights(rp, newfds); goto next; } FILEDESC_LOCK(td->td_proc->p_fd); /* if the new FD's will not fit free them. */ if (!fdavail(td, newfds)) { FILEDESC_UNLOCK(td->td_proc->p_fd); error = EMSGSIZE; unp_freerights(rp, newfds); goto next; } /* * now change each pointer to an fd in the global * table to an integer that is the index to the * local fd table entry that we set up to point * to the global one we are transferring. */ newlen = newfds * sizeof(int); *controlp = sbcreatecontrol(NULL, newlen, SCM_RIGHTS, SOL_SOCKET); if (*controlp == NULL) { FILEDESC_UNLOCK(td->td_proc->p_fd); error = E2BIG; unp_freerights(rp, newfds); goto next; } fdp = (int *) CMSG_DATA(mtod(*controlp, struct cmsghdr *)); for (i = 0; i < newfds; i++) { if (fdalloc(td, 0, &f)) panic("unp_externalize fdalloc failed"); fp = *rp++; td->td_proc->p_fd->fd_ofiles[f] = fp; FILE_LOCK(fp); fp->f_msgcount--; FILE_UNLOCK(fp); unp_rights--; *fdp++ = f; } FILEDESC_UNLOCK(td->td_proc->p_fd); } else { /* We can just copy anything else across */ if (error || controlp == NULL) goto next; *controlp = sbcreatecontrol(NULL, datalen, cm->cmsg_type, cm->cmsg_level); if (*controlp == NULL) { error = ENOBUFS; goto next; } bcopy(data, CMSG_DATA(mtod(*controlp, struct cmsghdr *)), datalen); } controlp = &(*controlp)->m_next; next: if (CMSG_SPACE(datalen) < clen) { clen -= CMSG_SPACE(datalen); cm = (struct cmsghdr *) ((caddr_t)cm + CMSG_SPACE(datalen)); } else { clen = 0; cm = NULL; } } m_freem(control); return (error); } void unp_init(void) { unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); if (unp_zone == NULL) panic("unp_init"); uma_zone_set_max(unp_zone, nmbclusters); LIST_INIT(&unp_dhead); LIST_INIT(&unp_shead); UNP_LOCK_INIT(); } static int unp_internalize(controlp, td) struct mbuf **controlp; struct thread *td; { struct mbuf *control = *controlp; struct proc *p = td->td_proc; struct filedesc *fdescp = p->p_fd; struct cmsghdr *cm = mtod(control, struct cmsghdr *); struct cmsgcred *cmcred; struct file **rp; struct file *fp; struct timeval *tv; int i, fd, *fdp; void *data; socklen_t clen = control->m_len, datalen; int error, oldfds; u_int newlen; UNP_UNLOCK_ASSERT(); error = 0; *controlp = NULL; while (cm != NULL) { if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET || cm->cmsg_len > clen) { error = EINVAL; goto out; } data = CMSG_DATA(cm); datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; switch (cm->cmsg_type) { /* * Fill in credential information. */ case SCM_CREDS: *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), SCM_CREDS, SOL_SOCKET); if (*controlp == NULL) { error = ENOBUFS; goto out; } cmcred = (struct cmsgcred *) CMSG_DATA(mtod(*controlp, struct cmsghdr *)); cmcred->cmcred_pid = p->p_pid; cmcred->cmcred_uid = td->td_ucred->cr_ruid; cmcred->cmcred_gid = td->td_ucred->cr_rgid; cmcred->cmcred_euid = td->td_ucred->cr_uid; cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); for (i = 0; i < cmcred->cmcred_ngroups; i++) cmcred->cmcred_groups[i] = td->td_ucred->cr_groups[i]; break; case SCM_RIGHTS: oldfds = datalen / sizeof (int); /* * check that all the FDs passed in refer to legal files * If not, reject the entire operation. */ fdp = data; FILEDESC_LOCK(fdescp); for (i = 0; i < oldfds; i++) { fd = *fdp++; if ((unsigned)fd >= fdescp->fd_nfiles || fdescp->fd_ofiles[fd] == NULL) { FILEDESC_UNLOCK(fdescp); error = EBADF; goto out; } fp = fdescp->fd_ofiles[fd]; if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { FILEDESC_UNLOCK(fdescp); error = EOPNOTSUPP; goto out; } } /* * Now replace the integer FDs with pointers to * the associated global file table entry.. */ newlen = oldfds * sizeof(struct file *); *controlp = sbcreatecontrol(NULL, newlen, SCM_RIGHTS, SOL_SOCKET); if (*controlp == NULL) { FILEDESC_UNLOCK(fdescp); error = E2BIG; goto out; } fdp = data; rp = (struct file **) CMSG_DATA(mtod(*controlp, struct cmsghdr *)); for (i = 0; i < oldfds; i++) { fp = fdescp->fd_ofiles[*fdp++]; *rp++ = fp; FILE_LOCK(fp); fp->f_count++; fp->f_msgcount++; FILE_UNLOCK(fp); unp_rights++; } FILEDESC_UNLOCK(fdescp); break; case SCM_TIMESTAMP: *controlp = sbcreatecontrol(NULL, sizeof(*tv), SCM_TIMESTAMP, SOL_SOCKET); if (*controlp == NULL) { error = ENOBUFS; goto out; } tv = (struct timeval *) CMSG_DATA(mtod(*controlp, struct cmsghdr *)); microtime(tv); break; default: error = EINVAL; goto out; } controlp = &(*controlp)->m_next; if (CMSG_SPACE(datalen) < clen) { clen -= CMSG_SPACE(datalen); cm = (struct cmsghdr *) ((caddr_t)cm + CMSG_SPACE(datalen)); } else { clen = 0; cm = NULL; } } out: m_freem(control); return (error); } static int unp_defer, unp_gcing; static void unp_gc() { register struct file *fp, *nextfp; register struct socket *so; struct file **extra_ref, **fpp; int nunref, i; int nfiles_snap; int nfiles_slack = 20; UNP_LOCK_ASSERT(); if (unp_gcing) return; unp_gcing = 1; unp_defer = 0; /* * before going through all this, set all FDs to * be NOT defered and NOT externally accessible */ /* * XXXRW: Acquiring a sleep lock while holding UNP * mutex cannot be a good thing. */ sx_slock(&filelist_lock); LIST_FOREACH(fp, &filehead, f_list) fp->f_gcflag &= ~(FMARK|FDEFER); do { LIST_FOREACH(fp, &filehead, f_list) { FILE_LOCK(fp); /* * If the file is not open, skip it */ if (fp->f_count == 0) { FILE_UNLOCK(fp); continue; } /* * If we already marked it as 'defer' in a * previous pass, then try process it this time * and un-mark it */ if (fp->f_gcflag & FDEFER) { fp->f_gcflag &= ~FDEFER; unp_defer--; } else { /* * if it's not defered, then check if it's * already marked.. if so skip it */ if (fp->f_gcflag & FMARK) { FILE_UNLOCK(fp); continue; } /* * If all references are from messages * in transit, then skip it. it's not * externally accessible. */ if (fp->f_count == fp->f_msgcount) { FILE_UNLOCK(fp); continue; } /* * If it got this far then it must be * externally accessible. */ fp->f_gcflag |= FMARK; } /* * either it was defered, or it is externally * accessible and not already marked so. * Now check if it is possibly one of OUR sockets. */ if (fp->f_type != DTYPE_SOCKET || (so = fp->f_data) == NULL) { FILE_UNLOCK(fp); continue; } FILE_UNLOCK(fp); if (so->so_proto->pr_domain != &localdomain || (so->so_proto->pr_flags&PR_RIGHTS) == 0) continue; #ifdef notdef if (so->so_rcv.sb_flags & SB_LOCK) { /* * This is problematical; it's not clear * we need to wait for the sockbuf to be * unlocked (on a uniprocessor, at least), * and it's also not clear what to do * if sbwait returns an error due to receipt * of a signal. If sbwait does return * an error, we'll go into an infinite * loop. Delete all of this for now. */ (void) sbwait(&so->so_rcv); goto restart; } #endif /* * So, Ok, it's one of our sockets and it IS externally * accessible (or was defered). Now we look * to see if we hold any file descriptors in its * message buffers. Follow those links and mark them * as accessible too. */ SOCKBUF_LOCK(&so->so_rcv); unp_scan(so->so_rcv.sb_mb, unp_mark); SOCKBUF_UNLOCK(&so->so_rcv); } } while (unp_defer); sx_sunlock(&filelist_lock); /* * We grab an extra reference to each of the file table entries * that are not otherwise accessible and then free the rights * that are stored in messages on them. * * The bug in the orginal code is a little tricky, so I'll describe * what's wrong with it here. * * It is incorrect to simply unp_discard each entry for f_msgcount * times -- consider the case of sockets A and B that contain * references to each other. On a last close of some other socket, * we trigger a gc since the number of outstanding rights (unp_rights) * is non-zero. If during the sweep phase the gc code un_discards, * we end up doing a (full) closef on the descriptor. A closef on A * results in the following chain. Closef calls soo_close, which * calls soclose. Soclose calls first (through the switch * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply * returns because the previous instance had set unp_gcing, and * we return all the way back to soclose, which marks the socket * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush * to free up the rights that are queued in messages on the socket A, * i.e., the reference on B. The sorflush calls via the dom_dispose * switch unp_dispose, which unp_scans with unp_discard. This second * instance of unp_discard just calls closef on B. * * Well, a similar chain occurs on B, resulting in a sorflush on B, * which results in another closef on A. Unfortunately, A is already * being closed, and the descriptor has already been marked with * SS_NOFDREF, and soclose panics at this point. * * Here, we first take an extra reference to each inaccessible * descriptor. Then, we call sorflush ourself, since we know * it is a Unix domain socket anyhow. After we destroy all the * rights carried in messages, we do a last closef to get rid * of our extra reference. This is the last close, and the * unp_detach etc will shut down the socket. * * 91/09/19, bsy@cs.cmu.edu */ again: nfiles_snap = nfiles + nfiles_slack; /* some slack */ extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, M_WAITOK); sx_slock(&filelist_lock); if (nfiles_snap < nfiles) { sx_sunlock(&filelist_lock); free(extra_ref, M_TEMP); nfiles_slack += 20; goto again; } for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; fp != NULL; fp = nextfp) { nextfp = LIST_NEXT(fp, f_list); FILE_LOCK(fp); /* * If it's not open, skip it */ if (fp->f_count == 0) { FILE_UNLOCK(fp); continue; } /* * If all refs are from msgs, and it's not marked accessible * then it must be referenced from some unreachable cycle * of (shut-down) FDs, so include it in our * list of FDs to remove */ if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { *fpp++ = fp; nunref++; fp->f_count++; } FILE_UNLOCK(fp); } sx_sunlock(&filelist_lock); /* * for each FD on our hit list, do the following two things */ for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { struct file *tfp = *fpp; FILE_LOCK(tfp); if (tfp->f_type == DTYPE_SOCKET && tfp->f_data != NULL) { FILE_UNLOCK(tfp); sorflush(tfp->f_data); } else { FILE_UNLOCK(tfp); } } for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) closef(*fpp, (struct thread *) NULL); free(extra_ref, M_TEMP); unp_gcing = 0; } void unp_dispose(m) struct mbuf *m; { if (m) unp_scan(m, unp_discard); } static int unp_listen(unp, td) struct unpcb *unp; struct thread *td; { UNP_LOCK_ASSERT(); /* * XXXRW: Why populate the local peer cred with our own credential? */ cru2x(td->td_ucred, &unp->unp_peercred); unp->unp_flags |= UNP_HAVEPCCACHED; return (0); } static void unp_scan(m0, op) register struct mbuf *m0; void (*op)(struct file *); { struct mbuf *m; struct file **rp; struct cmsghdr *cm; void *data; int i; socklen_t clen, datalen; int qfds; while (m0 != NULL) { for (m = m0; m; m = m->m_next) { if (m->m_type != MT_CONTROL) continue; cm = mtod(m, struct cmsghdr *); clen = m->m_len; while (cm != NULL) { if (sizeof(*cm) > clen || cm->cmsg_len > clen) break; data = CMSG_DATA(cm); datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; if (cm->cmsg_level == SOL_SOCKET && cm->cmsg_type == SCM_RIGHTS) { qfds = datalen / sizeof (struct file *); rp = data; for (i = 0; i < qfds; i++) (*op)(*rp++); } if (CMSG_SPACE(datalen) < clen) { clen -= CMSG_SPACE(datalen); cm = (struct cmsghdr *) ((caddr_t)cm + CMSG_SPACE(datalen)); } else { clen = 0; cm = NULL; } } } m0 = m0->m_act; } } static void unp_mark(fp) struct file *fp; { if (fp->f_gcflag & FMARK) return; unp_defer++; fp->f_gcflag |= (FMARK|FDEFER); } static void unp_discard(fp) struct file *fp; { FILE_LOCK(fp); fp->f_msgcount--; unp_rights--; FILE_UNLOCK(fp); (void) closef(fp, (struct thread *)NULL); }