From b9fedbd75bbb6bbc04e73515d21b1ad653b69e01 Mon Sep 17 00:00:00 2001 From: hselasky Date: Thu, 24 Jan 2019 08:25:02 +0000 Subject: [PATCH] When detaching a network interface drain the workqueue freeing the inm's because the destructor will access the if_ioctl() callback in the ifnet pointer which is about to be freed. This prevents use-after-free. PR: 233535 Differential Revision: https://reviews.freebsd.org/D18887 Reviewed by: bz (net) Tested by: ae MFC after: 1 week Sponsored by: Mellanox Technologies --- sys/netinet6/in6_ifattach.c | 7 +++++++ sys/netinet6/in6_mcast.c | 8 ++++++++ sys/netinet6/in6_var.h | 1 + 3 files changed, 16 insertions(+) diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c index 1e9901125f6..14df5fff645 100644 --- a/sys/netinet6/in6_ifattach.c +++ b/sys/netinet6/in6_ifattach.c @@ -884,6 +884,13 @@ in6_purgemaddrs(struct ifnet *ifp) IN6_MULTI_LIST_UNLOCK(); IN6_MULTI_UNLOCK(); in6m_release_list_deferred(&purgeinms); + + /* + * Make sure all multicast deletions invoking if_ioctl() are + * completed before returning. Else we risk accessing a freed + * ifnet structure pointer. + */ + in6m_release_wait(); } void diff --git a/sys/netinet6/in6_mcast.c b/sys/netinet6/in6_mcast.c index 6d27614273c..693345b1c5e 100644 --- a/sys/netinet6/in6_mcast.c +++ b/sys/netinet6/in6_mcast.c @@ -584,6 +584,14 @@ in6m_release_list_deferred(struct in6_multi_head *inmh) GROUPTASK_ENQUEUE(&free_gtask); } +void +in6m_release_wait(void) +{ + + /* Wait for all jobs to complete. */ + gtaskqueue_drain_all(free_gtask.gt_taskqueue); +} + void in6m_disconnect(struct in6_multi *inm) { diff --git a/sys/netinet6/in6_var.h b/sys/netinet6/in6_var.h index 746aed35945..a19747d9791 100644 --- a/sys/netinet6/in6_var.h +++ b/sys/netinet6/in6_var.h @@ -811,6 +811,7 @@ void in6m_print(const struct in6_multi *); int in6m_record_source(struct in6_multi *, const struct in6_addr *); void in6m_release_deferred(struct in6_multi *); void in6m_release_list_deferred(struct in6_multi_head *); +void in6m_release_wait(void); void ip6_freemoptions(struct ip6_moptions *); int ip6_getmoptions(struct inpcb *, struct sockopt *); int ip6_setmoptions(struct inpcb *, struct sockopt *); -- 2.45.0