Author: rstone Date: Sat Nov 12 19:03:23 2016 New Revision: 308580 URL: https://svnweb.freebsd.org/changeset/base/308580
Log: 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: head/sys/net/rtsock.c Modified: head/sys/net/rtsock.c ============================================================================== --- head/sys/net/rtsock.c Sat Nov 12 18:57:38 2016 (r308579) +++ head/sys/net/rtsock.c Sat Nov 12 19:03:23 2016 (r308580) @@ -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; } _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
