Author: markj
Date: Wed Aug 31 21:35:51 2016
New Revision: 305161
URL: https://svnweb.freebsd.org/changeset/base/305161
Log:
MFC 303855:
Handle races with listening socket close when connecting a unix socket.
PR: 211531
Modified:
stable/10/sys/kern/uipc_usrreq.c
stable/10/sys/sys/unpcb.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/kern/uipc_usrreq.c
==============================================================================
--- stable/10/sys/kern/uipc_usrreq.c Wed Aug 31 21:35:38 2016
(r305160)
+++ stable/10/sys/kern/uipc_usrreq.c Wed Aug 31 21:35:51 2016
(r305161)
@@ -429,6 +429,8 @@ uipc_attach(struct socket *so, int proto
unp->unp_socket = so;
so->so_pcb = unp;
unp->unp_refcount = 1;
+ if (so->so_head != NULL)
+ unp->unp_flags |= UNP_NASCENT;
UNP_LIST_LOCK();
unp->unp_gencnt = ++unp_gencnt;
@@ -651,14 +653,22 @@ uipc_detach(struct socket *so)
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
- UNP_LINK_WLOCK();
+ vp = NULL;
+ local_unp_rights = 0;
+
UNP_LIST_LOCK();
- UNP_PCB_LOCK(unp);
LIST_REMOVE(unp, unp_link);
unp->unp_gencnt = ++unp_gencnt;
--unp_count;
UNP_LIST_UNLOCK();
+ if ((unp->unp_flags & UNP_NASCENT) != 0) {
+ UNP_PCB_LOCK(unp);
+ goto teardown;
+ }
+ UNP_LINK_WLOCK();
+ UNP_PCB_LOCK(unp);
+
/*
* XXXRW: Should assert vp->v_socket == so.
*/
@@ -686,6 +696,7 @@ uipc_detach(struct socket *so)
}
local_unp_rights = unp_rights;
UNP_LINK_WUNLOCK();
+teardown:
unp->unp_socket->so_pcb = NULL;
saved_unp_addr = unp->unp_addr;
unp->unp_addr = NULL;
@@ -1441,6 +1452,7 @@ unp_connect2(struct socket *so, struct s
if (so2->so_type != so->so_type)
return (EPROTOTYPE);
+ unp2->unp_flags &= ~UNP_NASCENT;
unp->unp_conn = unp2;
switch (so->so_type) {
Modified: stable/10/sys/sys/unpcb.h
==============================================================================
--- stable/10/sys/sys/unpcb.h Wed Aug 31 21:35:38 2016 (r305160)
+++ stable/10/sys/sys/unpcb.h Wed Aug 31 21:35:51 2016 (r305161)
@@ -103,10 +103,6 @@ struct unpcb {
#define UNP_WANTCRED 0x004 /* credentials wanted */
#define UNP_CONNWAIT 0x008 /* connect blocks until
accepted */
-#define UNPGC_REF 0x1 /* unpcb has external
ref. */
-#define UNPGC_DEAD 0x2 /* unpcb might be dead.
*/
-#define UNPGC_SCANNED 0x4 /* Has been scanned. */
-
/*
* These flags are used to handle non-atomicity in connect() and bind()
* operations on a socket: in particular, to avoid races between multiple
@@ -114,6 +110,14 @@ struct unpcb {
*/
#define UNP_CONNECTING 0x010 /* Currently
connecting. */
#define UNP_BINDING 0x020 /* Currently binding. */
+#define UNP_NASCENT 0x040 /* Newborn child
socket. */
+
+/*
+ * Flags in unp_gcflag.
+ */
+#define UNPGC_REF 0x1 /* unpcb has external
ref. */
+#define UNPGC_DEAD 0x2 /* unpcb might be dead.
*/
+#define UNPGC_SCANNED 0x4 /* Has been scanned. */
#define sotounpcb(so) ((struct unpcb *)((so)->so_pcb))
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