Date: Wed, 31 Aug 2016 21:35:51 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r305161 - in stable/10/sys: kern sys Message-ID: <201608312135.u7VLZpHO022095@repo.freebsd.org>
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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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