Date: Sat, 26 Nov 2016 01:16:33 +0000 (UTC) From: Ryan Stone <rstone@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r309177 - stable/11/sys/net Message-ID: <201611260116.uAQ1GXEh021082@repo.freebsd.org>
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Author: rstone Date: Sat Nov 26 01:16:33 2016 New Revision: 309177 URL: https://svnweb.freebsd.org/changeset/base/309177 Log: MFC r308580: Don't read if_counters with if_addr_lock held Calling into an ifnet implementation with the if_addr_lock already held can cause a LOR and potentially a deadlock, as ifnet implementations typically can take the if_addr_lock after their own locks during configuration. Refactor a sysctl handler that was violating this to read if_counter data in a temporary buffer before the if_addr_lock is taken, and then copying the data in its final location later, when the if_addr_lock is held. PR: 194109 Reported by: Jean-Sebastien Pedron MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D8498 Reviewed by: sbruno Modified: stable/11/sys/net/rtsock.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/net/rtsock.c ============================================================================== --- stable/11/sys/net/rtsock.c Sat Nov 26 01:13:53 2016 (r309176) +++ stable/11/sys/net/rtsock.c Sat Nov 26 01:16:33 2016 (r309177) @@ -1566,8 +1566,8 @@ sysctl_dumpentry(struct radix_node *rn, } static int -sysctl_iflist_ifml(struct ifnet *ifp, struct rt_addrinfo *info, - struct walkarg *w, int len) +sysctl_iflist_ifml(struct ifnet *ifp, const struct if_data *src_ifd, + struct rt_addrinfo *info, struct walkarg *w, int len) { struct if_msghdrl *ifm; struct if_data *ifd; @@ -1598,14 +1598,14 @@ sysctl_iflist_ifml(struct ifnet *ifp, st ifd = &ifm->ifm_data; } - if_data_copy(ifp, ifd); + memcpy(ifd, src_ifd, sizeof(*ifd)); return (SYSCTL_OUT(w->w_req, (caddr_t)ifm, len)); } static int -sysctl_iflist_ifm(struct ifnet *ifp, struct rt_addrinfo *info, - struct walkarg *w, int len) +sysctl_iflist_ifm(struct ifnet *ifp, const struct if_data *src_ifd, + struct rt_addrinfo *info, struct walkarg *w, int len) { struct if_msghdr *ifm; struct if_data *ifd; @@ -1630,7 +1630,7 @@ sysctl_iflist_ifm(struct ifnet *ifp, str ifd = &ifm->ifm_data; } - if_data_copy(ifp, ifd); + memcpy(ifd, src_ifd, sizeof(*ifd)); return (SYSCTL_OUT(w->w_req, (caddr_t)ifm, len)); } @@ -1705,15 +1705,18 @@ sysctl_iflist(int af, struct walkarg *w) { struct ifnet *ifp; struct ifaddr *ifa; + struct if_data ifd; struct rt_addrinfo info; int len, error = 0; struct sockaddr_storage ss; bzero((caddr_t)&info, sizeof(info)); + bzero(&ifd, sizeof(ifd)); IFNET_RLOCK_NOSLEEP(); TAILQ_FOREACH(ifp, &V_ifnet, if_link) { if (w->w_arg && w->w_arg != ifp->if_index) continue; + if_data_copy(ifp, &ifd); IF_ADDR_RLOCK(ifp); ifa = ifp->if_addr; info.rti_info[RTAX_IFP] = ifa->ifa_addr; @@ -1723,9 +1726,11 @@ sysctl_iflist(int af, struct walkarg *w) info.rti_info[RTAX_IFP] = NULL; if (w->w_req && w->w_tmem) { if (w->w_op == NET_RT_IFLISTL) - error = sysctl_iflist_ifml(ifp, &info, w, len); + error = sysctl_iflist_ifml(ifp, &ifd, &info, w, + len); else - error = sysctl_iflist_ifm(ifp, &info, w, len); + error = sysctl_iflist_ifm(ifp, &ifd, &info, w, + len); if (error) goto done; }
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