From owner-svn-src-all@freebsd.org Thu Apr 25 12:44:09 2019 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7682815962B6; Thu, 25 Apr 2019 12:44:09 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1B78B82F2A; Thu, 25 Apr 2019 12:44:09 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id EA23123E0D; Thu, 25 Apr 2019 12:44:08 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x3PCi845096202; Thu, 25 Apr 2019 12:44:08 GMT (envelope-from kevans@FreeBSD.org) Received: (from kevans@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x3PCi8g0096201; Thu, 25 Apr 2019 12:44:08 GMT (envelope-from kevans@FreeBSD.org) Message-Id: <201904251244.x3PCi8g0096201@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kevans set sender to kevans@FreeBSD.org using -f From: Kyle Evans Date: Thu, 25 Apr 2019 12:44:08 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r346670 - head/sys/net X-SVN-Group: head X-SVN-Commit-Author: kevans X-SVN-Commit-Paths: head/sys/net X-SVN-Commit-Revision: 346670 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 1B78B82F2A X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.96 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; NEURAL_HAM_SHORT(-0.96)[-0.964,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Apr 2019 12:44:09 -0000 Author: kevans Date: Thu Apr 25 12:44:08 2019 New Revision: 346670 URL: https://svnweb.freebsd.org/changeset/base/346670 Log: tun/tap: close race between destroy/ioctl handler It seems that there should be a better way to handle this, but this seems to be the more common approach and it should likely get replaced in all of the places it happens... Basically, thread 1 is in the process of destroying the tun/tap while thread 2 is executing one of the ioctls that requires the tun/tap mutex and the mutex is destroyed before the ioctl handler can acquire it. This is only one of the races described/found in PR 233955. PR: 233955 Reviewed by: ae MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D20027 Modified: head/sys/net/if_tap.c head/sys/net/if_tun.c Modified: head/sys/net/if_tap.c ============================================================================== --- head/sys/net/if_tap.c Thu Apr 25 12:02:17 2019 (r346669) +++ head/sys/net/if_tap.c Thu Apr 25 12:44:08 2019 (r346670) @@ -41,6 +41,7 @@ #include #include +#include #include #include #include @@ -55,6 +56,7 @@ #include #include #include +#include #include #include #include @@ -163,6 +165,9 @@ MALLOC_DECLARE(M_TAP); MALLOC_DEFINE(M_TAP, CDEV_NAME, "Ethernet tunnel interface"); SYSCTL_INT(_debug, OID_AUTO, if_tap_debug, CTLFLAG_RW, &tapdebug, 0, ""); +static struct sx tap_ioctl_sx; +SX_SYSINIT(tap_ioctl_sx, &tap_ioctl_sx, "tap_ioctl"); + SYSCTL_DECL(_net_link); static SYSCTL_NODE(_net_link, OID_AUTO, tap, CTLFLAG_RW, 0, "Ethernet tunnel software network interface"); @@ -217,6 +222,10 @@ tap_destroy(struct tap_softc *tp) struct ifnet *ifp = tp->tap_ifp; CURVNET_SET(ifp->if_vnet); + sx_xlock(&tap_ioctl_sx); + ifp->if_softc = NULL; + sx_xunlock(&tap_ioctl_sx); + destroy_dev(tp->tap_dev); seldrain(&tp->tap_rsel); knlist_clear(&tp->tap_rsel.si_note, 0); @@ -600,12 +609,18 @@ tapifinit(void *xtp) static int tapifioctl(struct ifnet *ifp, u_long cmd, caddr_t data) { - struct tap_softc *tp = ifp->if_softc; + struct tap_softc *tp; struct ifreq *ifr = (struct ifreq *)data; struct ifstat *ifs = NULL; struct ifmediareq *ifmr = NULL; int dummy, error = 0; + sx_xlock(&tap_ioctl_sx); + tp = ifp->if_softc; + if (tp == NULL) { + error = ENXIO; + goto bad; + } switch (cmd) { case SIOCSIFFLAGS: /* XXX -- just like vmnet does */ case SIOCADDMULTI: @@ -648,6 +663,8 @@ tapifioctl(struct ifnet *ifp, u_long cmd, caddr_t data break; } +bad: + sx_xunlock(&tap_ioctl_sx); return (error); } /* tapifioctl */ Modified: head/sys/net/if_tun.c ============================================================================== --- head/sys/net/if_tun.c Thu Apr 25 12:02:17 2019 (r346669) +++ head/sys/net/if_tun.c Thu Apr 25 12:44:08 2019 (r346670) @@ -20,6 +20,7 @@ #include "opt_inet6.h" #include +#include #include #include #include @@ -30,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -115,6 +117,9 @@ static struct clonedevs *tunclones; static TAILQ_HEAD(,tun_softc) tunhead = TAILQ_HEAD_INITIALIZER(tunhead); SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); +static struct sx tun_ioctl_sx; +SX_SYSINIT(tun_ioctl_sx, &tun_ioctl_sx, "tun_ioctl"); + SYSCTL_DECL(_net_link); static SYSCTL_NODE(_net_link, OID_AUTO, tun, CTLFLAG_RW, 0, "IP tunnel software network interface."); @@ -278,6 +283,10 @@ tun_destroy(struct tun_softc *tp) mtx_unlock(&tp->tun_mtx); CURVNET_SET(TUN2IFP(tp)->if_vnet); + sx_xlock(&tun_ioctl_sx); + TUN2IFP(tp)->if_softc = NULL; + sx_xunlock(&tun_ioctl_sx); + dev = tp->tun_dev; bpfdetach(TUN2IFP(tp)); if_detach(TUN2IFP(tp)); @@ -588,10 +597,16 @@ static int tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data) { struct ifreq *ifr = (struct ifreq *)data; - struct tun_softc *tp = ifp->if_softc; + struct tun_softc *tp; struct ifstat *ifs; int error = 0; + sx_xlock(&tun_ioctl_sx); + tp = ifp->if_softc; + if (tp == NULL) { + error = ENXIO; + goto bad; + } switch(cmd) { case SIOCGIFSTATUS: ifs = (struct ifstat *)data; @@ -618,6 +633,8 @@ tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data default: error = EINVAL; } +bad: + sx_xunlock(&tun_ioctl_sx); return (error); }