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AF_UNIX: It is possible for UNIX datagram sockets to be connected

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to themselves. The updated code assumed that that could not happen
and would try to lock the unp mutex twice.

There may be a lingering issue here but this fixes it for the
reporter.

PR:	228458
Reported by:	marieheleneka at gmail.com
This commit is contained in:
Matt Macy 2018-05-24 21:13:46 +00:00
parent 509b94387a
commit acf9fd05d8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=334185
1 changed files with 27 additions and 13 deletions
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40
sys/kern/uipc_usrreq.c
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@ -722,7 +722,9 @@ uipc_close(struct socket *so)
}
unp2 = unp->unp_conn;
unp_pcb_hold(unp);
if (unp2 != NULL) {
if (__predict_false(unp == unp2)) {
unp_disconnect(unp, unp2);
} else if (unp2 != NULL) {
unp_pcb_hold(unp2);
unp_pcb_owned_lock2(unp, unp2, freed);
unp_disconnect(unp, unp2);
@ -747,9 +749,13 @@ uipc_connect2(struct socket *so1, struct socket *so2)
KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
unp2 = so2->so_pcb;
KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
unp_pcb_lock2(unp, unp2);
if (unp != unp2)
unp_pcb_lock2(unp, unp2);
else
UNP_PCB_LOCK(unp);
error = unp_connect2(so1, so2, PRU_CONNECT2);
UNP_PCB_UNLOCK(unp2);
if (unp != unp2)
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
return (error);
}
@ -783,29 +789,30 @@ uipc_detach(struct socket *so)
mtx_lock(vplock);
}
UNP_PCB_LOCK(unp);
if ((unp2 = unp->unp_conn) != NULL) {
unp_pcb_owned_lock2(unp, unp2, freeunp);
if (freeunp)
unp2 = NULL;
}
if (unp->unp_vnode != vp &&
unp->unp_vnode != NULL) {
if (vplock)
mtx_unlock(vplock);
UNP_PCB_UNLOCK(unp);
if (unp2)
UNP_PCB_UNLOCK(unp2);
goto restart;
}
if ((unp->unp_flags & UNP_NASCENT) != 0) {
if (unp2)
UNP_PCB_UNLOCK(unp2);
goto teardown;
}
if ((vp = unp->unp_vnode) != NULL) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
}
if (__predict_false(unp == unp->unp_conn)) {
unp_disconnect(unp, unp);
unp2 = NULL;
goto connect_self;
}
if ((unp2 = unp->unp_conn) != NULL) {
unp_pcb_owned_lock2(unp, unp2, freeunp);
if (freeunp)
unp2 = NULL;
}
unp_pcb_hold(unp);
if (unp2 != NULL) {
unp_pcb_hold(unp2);
@ -813,6 +820,7 @@ uipc_detach(struct socket *so)
if (unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
}
connect_self:
UNP_PCB_UNLOCK(unp);
UNP_REF_LIST_LOCK();
while (!LIST_EMPTY(&unp->unp_refs)) {
@ -864,6 +872,10 @@ uipc_disconnect(struct socket *so)
UNP_PCB_UNLOCK(unp);
return (0);
}
if (unp == unp2) {
if (unp_pcb_rele(unp) == 0)
UNP_PCB_UNLOCK(unp);
}
unp_pcb_owned_lock2(unp, unp2, freed);
if (__predict_false(freed)) {
UNP_PCB_UNLOCK(unp);
@ -1925,7 +1937,9 @@ unp_drop(struct unpcb *unp)
if (so)
so->so_error = ECONNRESET;
unp2 = unp->unp_conn;
if (unp2 != NULL) {
if (unp2 == unp) {
unp_disconnect(unp, unp2);
} else if (unp2 != NULL) {
unp_pcb_hold(unp2);
unp_pcb_owned_lock2(unp, unp2, freed);
unp_disconnect(unp, unp2);