Date: Tue, 9 Aug 2016 01:51:35 +0200 From: Oliver Pinter <oliver.pinter@hardenedbsd.org> To: Mark Johnston <markj@freebsd.org> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, Bryan Drewery <bdrewery@freebsd.org> Subject: Re: svn commit: r303855 - in head/sys: kern sys Message-ID: <CAPQ4ffsm6NBC%2BOT0pU21hTvZgQ9eD9KqQiA4hhDHP1oG=8c8yQ@mail.gmail.com> In-Reply-To: <20160808234332.GA22449@wkstn-mjohnston.west.isilon.com> References: <201608082025.u78KP4aE048791@repo.freebsd.org> <CAPQ4ffsmwTAL%2Bv9RgY8e_%2Bn5CZKKL9ejNntuSNM71MQma5_o2w@mail.gmail.com> <20160808234332.GA22449@wkstn-mjohnston.west.isilon.com>
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(Added bdrewery to CC, since I'm talking with him on IRC.) On Tue, Aug 9, 2016 at 1:43 AM, Mark Johnston <markj@freebsd.org> wrote: > On Tue, Aug 09, 2016 at 12:53:47AM +0200, Oliver Pinter wrote: >> Hi! >> >> Can you please MFC back this change 10-STABLE together with the >> following: https://github.com/HardenedBSD/hardenedBSD/commit/576619e564618bca3675db57580d8e1f76bd2ac7 >> >> This issue is still exists on 10-STABLE, as you can test with the >> linked program from phabricator: >> https://people.freebsd.org/~mjg/reproducers/unp-gc-panic.c > > Hm, I don't think this could be MFCed directly. It changes the kernel > ABI by modifying the argument of dom_dispose(). This could be fixed in > stable/10 with a hack to call the unix domain socket code directly when > appropriate, which I think is preferable to the current state of things. > I'll look into it further. The question is how much external / out of tree components would use this ABI or how acceptable to break this ABI. I just grepped through the src tree for internal uses, and I found only these: op@opn hardenedBSD.git> git grep dom_dispose share/doc/smm/18.net/6.t: int (*dom_dispose)(); /* dispose of internalized rights */ share/man/man9/domain.9: void (*dom_dispose) /* dispose of internalized rights */ sys/kern/uipc_debug.c: db_printf("dom_dispose: %p\n", d->dom_dispose); sys/kern/uipc_socket.c: if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL) sys/kern/uipc_socket.c: (*pr->pr_domain->dom_dispose)(so); sys/kern/uipc_socket.c: * dom_dispose() and sbrelease_internal() are an inlining of what was sys/kern/uipc_socket.c: * In order to avoid calling dom_dispose with the socket buffer mutex sys/kern/uipc_socket.c: if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL) sys/kern/uipc_socket.c: (*pr->pr_domain->dom_dispose)(&aso); sys/kern/uipc_usrreq.c: .dom_dispose = unp_dispose_so, sys/sys/domain.h: void (*dom_dispose) /* dispose of internalized rights */ > >> >> On Mon, Aug 8, 2016 at 10:25 PM, Mark Johnston <markj@freebsd.org> wrote: >> > Author: markj >> > Date: Mon Aug 8 20:25:04 2016 >> > New Revision: 303855 >> > URL: https://svnweb.freebsd.org/changeset/base/303855 >> > >> > Log: >> > Handle races with listening socket close when connecting a unix socket. >> > >> > If the listening socket is closed while sonewconn() is executing, the >> > nascent child socket is aborted, which results in recursion on the >> > unp_link lock when the child's pru_detach method is invoked. Fix this >> > by using a flag to mark such sockets, and skip a part of the socket's >> > teardown during detach. >> > >> > Reported by: Raviprakash Darbha <rdarbha@juniper.net> >> > Tested by: pho >> > MFC after: 2 weeks >> > Differential Revision: https://reviews.freebsd.org/D7398 >> > >> > Modified: >> > head/sys/kern/uipc_usrreq.c >> > head/sys/sys/unpcb.h >> > >> > Modified: head/sys/kern/uipc_usrreq.c >> > ============================================================================== >> > --- head/sys/kern/uipc_usrreq.c Mon Aug 8 20:23:11 2016 (r303854) >> > +++ head/sys/kern/uipc_usrreq.c Mon Aug 8 20:25:04 2016 (r303855) >> > @@ -430,6 +430,8 @@ 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; >> > @@ -652,14 +654,22 @@ 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. >> > */ >> > @@ -687,6 +697,7 @@ 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; >> > @@ -1473,6 +1484,7 @@ 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: head/sys/sys/unpcb.h >> > ============================================================================== >> > --- head/sys/sys/unpcb.h Mon Aug 8 20:23:11 2016 (r303854) >> > +++ head/sys/sys/unpcb.h Mon Aug 8 20:25:04 2016 (r303855) >> > @@ -103,11 +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. */ >> > -#define UNPGC_IGNORE_RIGHTS 0x8 /* Attached rights are freed */ >> > - >> > /* >> > * These flags are used to handle non-atomicity in connect() and bind() >> > * operations on a socket: in particular, to avoid races between multiple >> > @@ -115,6 +110,15 @@ 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 UNPGC_IGNORE_RIGHTS 0x8 /* Attached rights are freed */ >> > >> > #define sotounpcb(so) ((struct unpcb *)((so)->so_pcb)) >> > >> > _______________________________________________ >> > svn-src-head@freebsd.org mailing list >> > https://lists.freebsd.org/mailman/listinfo/svn-src-head >> > To unsubscribe, send any mail to "svn-src-head-unsubscribe@freebsd.org"
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