On Mon, Feb 17, 2020 at 09:46:32AM +0000, Hans Petter Selasky wrote: H> Author: hselasky H> Date: Mon Feb 17 09:46:32 2020 H> New Revision: 358013 H> URL: https://svnweb.freebsd.org/changeset/base/358013 H> H> Log: H> Fix kernel panic while trying to read multicast stream. H> H> When VIMAGE is enabled make sure the "m_pkthdr.rcvif" pointer is set H> for all mbufs being input by the IGMP/MLD6 code. Else there will be a H> NULL-pointer dereference in the netisr code when trying to set the H> VNET based on the incoming mbuf. Add an assert to catch this when H> queueing mbufs on a netisr to make debugging of similar cases easier. H> H> Found by: Vladislav V. Prodan H> PR: 244002 H> Reviewed by: bz@ H> MFC after: 1 week H> Sponsored by: Mellanox Technologies H> H> Modified: H> head/sys/net/netisr.c H> head/sys/netinet/igmp.c H> head/sys/netinet6/mld6.c H> H> Modified: head/sys/net/netisr.c H> ============================================================================== H> --- head/sys/net/netisr.c Mon Feb 17 01:59:55 2020 (r358012) H> +++ head/sys/net/netisr.c Mon Feb 17 09:46:32 2020 (r358013) H> @@ -1056,6 +1056,8 @@ netisr_queue_src(u_int proto, uintptr_t source, struct H> if (m != NULL) { H> KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, H> cpuid)); H> + VNET_ASSERT(m->m_pkthdr.rcvif != NULL, H> + ("%s:%d rcvif == NULL: m=%p", __func__, __LINE__, m)); H> error = netisr_queue_internal(proto, m, cpuid); H> } else H> error = ENOBUFS; H> H> Modified: head/sys/netinet/igmp.c H> ============================================================================== H> --- head/sys/netinet/igmp.c Mon Feb 17 01:59:55 2020 (r358012) H> +++ head/sys/netinet/igmp.c Mon Feb 17 09:46:32 2020 (r358013) H> @@ -303,6 +303,7 @@ igmp_save_context(struct mbuf *m, struct ifnet *ifp) H> #ifdef VIMAGE H> m->m_pkthdr.PH_loc.ptr = ifp->if_vnet; H> #endif /* VIMAGE */ H> + m->m_pkthdr.rcvif = ifp; H> m->m_pkthdr.flowid = ifp->if_index; H> } H> H> H> Modified: head/sys/netinet6/mld6.c H> ============================================================================== H> --- head/sys/netinet6/mld6.c Mon Feb 17 01:59:55 2020 (r358012) H> +++ head/sys/netinet6/mld6.c Mon Feb 17 09:46:32 2020 (r358013) H> @@ -283,6 +283,7 @@ mld_save_context(struct mbuf *m, struct ifnet *ifp) H> #ifdef VIMAGE H> m->m_pkthdr.PH_loc.ptr = ifp->if_vnet; H> #endif /* VIMAGE */ H> + m->m_pkthdr.rcvif = ifp; H> m->m_pkthdr.flowid = ifp->if_index; H> }
This functions igmp_save_context() and mld_save_context() were clearly designed to avoid dereferencing an ifnet pointer after a packet has been queued and dequeued on IGMP/MLD internal queue. This patch now replicates the exactly same problem but with netisr queue. Of course netisr not always queues, sometimes dispatches directly, but it may do queue. I think same thing needs to be done to netisr internally - don't dereference m->m_pkthdr.rcvif on dequeued packets, but store the vnet info in the m->m_pkthdr.PH_loc.ptr before queueing. -- Gleb Smirnoff _______________________________________________ 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-unsubscr...@freebsd.org"
