From 5a1e222bfda79fa1cb0276f9cba320900a0ccfc8 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Tue, 14 May 2019 21:30:55 +0000
Subject: [PATCH] Close some races in multicast socket option handling.
r333175 converted the global multicast lock to a sleepable sx lock,
so the lock order with respect to the (non-sleepable) inp lock changed.
To handle this, r333175 and r333505 added code to drop the inp lock,
but this opened races that could leave multicast group description
structures in an inconsistent state. This change fixes the problem by
simply acquiring the global lock sooner. Along the way, this fixes
some LORs and bogus error handling introduced in r333175, and commits
some related cleanup.
Reported by: syzbot+ba7c4943547e0604faca@syzkaller.appspotmail.com
Reported by: syzbot+1b803796ab94d11a46f9@syzkaller.appspotmail.com
Reviewed by: ae
MFC after: 3 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20070
---
sys/netinet/in_mcast.c | 60 ++++++++++++++--------------------------
sys/netinet6/in6_mcast.c | 23 +++------------
2 files changed, 24 insertions(+), 59 deletions(-)
diff --git a/sys/netinet/in_mcast.c b/sys/netinet/in_mcast.c
index 2980c1a463ca..f07c2aa7bc32 100644
--- a/sys/netinet/in_mcast.c
+++ b/sys/netinet/in_mcast.c
@@ -1534,6 +1534,7 @@ inp_block_unblock_source(struct inpcb *inp, struct sockopt *sopt)
/*
* Check if we are actually a member of this group.
*/
+ IN_MULTI_LOCK();
imo = inp_findmoptions(inp);
idx = imo_match_group(imo, ifp, &gsa->sa);
if (idx == -1 || imo->imo_mfilters == NULL) {
@@ -1593,14 +1594,13 @@ inp_block_unblock_source(struct inpcb *inp, struct sockopt *sopt)
/*
* Begin state merge transaction at IGMP layer.
*/
- IN_MULTI_LOCK();
CTR1(KTR_IGMPV3, "%s: merge inm state", __func__);
IN_MULTI_LIST_LOCK();
error = inm_merge(inm, imf);
if (error) {
CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__);
IN_MULTI_LIST_UNLOCK();
- goto out_in_multi_locked;
+ goto out_imf_rollback;
}
CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__);
@@ -1609,9 +1609,6 @@ inp_block_unblock_source(struct inpcb *inp, struct sockopt *sopt)
if (error)
CTR1(KTR_IGMPV3, "%s: failed igmp downcall", __func__);
-out_in_multi_locked:
-
- IN_MULTI_UNLOCK();
out_imf_rollback:
if (error)
imf_rollback(imf);
@@ -1622,6 +1619,7 @@ out_imf_rollback:
out_inp_locked:
INP_WUNLOCK(inp);
+ IN_MULTI_UNLOCK();
return (error);
}
@@ -1680,10 +1678,10 @@ inp_findmoptions(struct inpcb *inp)
static void
inp_gcmoptions(struct ip_moptions *imo)
{
- struct in_mfilter *imf;
+ struct in_mfilter *imf;
struct in_multi *inm;
struct ifnet *ifp;
- size_t idx, nmships;
+ size_t idx, nmships;
nmships = imo->imo_num_memberships;
for (idx = 0; idx < nmships; ++idx) {
@@ -2142,12 +2140,12 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt)
CTR2(KTR_IGMPV3, "%s: unknown sopt_name %d",
__func__, sopt->sopt_name);
return (EOPNOTSUPP);
- break;
}
if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0)
return (EADDRNOTAVAIL);
+ IN_MULTI_LOCK();
imo = inp_findmoptions(inp);
idx = imo_match_group(imo, ifp, &gsa->sa);
if (idx == -1) {
@@ -2272,10 +2270,6 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Begin state merge transaction at IGMP layer.
*/
- in_pcbref(inp);
- INP_WUNLOCK(inp);
- IN_MULTI_LOCK();
-
if (is_new) {
error = in_joingroup_locked(ifp, &gsa->sin.sin_addr, imf,
&inm);
@@ -2286,6 +2280,8 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt)
goto out_imo_free;
}
inm_acquire(inm);
+ KASSERT(imo->imo_membership[idx] == NULL,
+ ("%s: imo_membership already allocated", __func__));
imo->imo_membership[idx] = inm;
} else {
CTR1(KTR_IGMPV3, "%s: merge inm state", __func__);
@@ -2295,7 +2291,7 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt)
CTR1(KTR_IGMPV3, "%s: failed to merge inm state",
__func__);
IN_MULTI_LIST_UNLOCK();
- goto out_in_multi_locked;
+ goto out_imf_rollback;
}
CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__);
error = igmp_change_state(inm);
@@ -2303,16 +2299,11 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt)
if (error) {
CTR1(KTR_IGMPV3, "%s: failed igmp downcall",
__func__);
- goto out_in_multi_locked;
+ goto out_imf_rollback;
}
}
-out_in_multi_locked:
-
- IN_MULTI_UNLOCK();
- INP_WLOCK(inp);
- if (in_pcbrele_wlocked(inp))
- return (ENXIO);
+out_imf_rollback:
if (error) {
imf_rollback(imf);
if (is_new)
@@ -2337,6 +2328,7 @@ out_imo_free:
out_inp_locked:
INP_WUNLOCK(inp);
+ IN_MULTI_UNLOCK();
return (error);
}
@@ -2463,6 +2455,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Find the membership in the membership array.
*/
+ IN_MULTI_LOCK();
imo = inp_findmoptions(inp);
idx = imo_match_group(imo, ifp, &gsa->sa);
if (idx == -1) {
@@ -2510,9 +2503,6 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Begin state merge transaction at IGMP layer.
*/
- in_pcbref(inp);
- INP_WUNLOCK(inp);
- IN_MULTI_LOCK();
if (is_final) {
/*
@@ -2528,7 +2518,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sopt)
CTR1(KTR_IGMPV3, "%s: failed to merge inm state",
__func__);
IN_MULTI_LIST_UNLOCK();
- goto out_in_multi_locked;
+ goto out_imf_rollback;
}
CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__);
@@ -2540,13 +2530,7 @@ inp_leave_group(struct inpcb *inp, struct sockopt *sopt)
}
}
-out_in_multi_locked:
-
- IN_MULTI_UNLOCK();
- INP_WLOCK(inp);
- if (in_pcbrele_wlocked(inp))
- return (ENXIO);
-
+out_imf_rollback:
if (error)
imf_rollback(imf);
else
@@ -2557,7 +2541,7 @@ out_in_multi_locked:
if (is_final) {
/* Remove the gap in the membership and filter array. */
KASSERT(RB_EMPTY(&imf->imf_sources),
- ("%s: imf_sources not empty", __func__));
+ ("%s: imf_sources (%p %p %zu) not empty", __func__, imf, imo, idx));
for (++idx; idx < imo->imo_num_memberships; ++idx) {
imo->imo_membership[idx - 1] = imo->imo_membership[idx];
imo->imo_mfilters[idx - 1] = imo->imo_mfilters[idx];
@@ -2569,6 +2553,7 @@ out_in_multi_locked:
out_inp_locked:
INP_WUNLOCK(inp);
+ IN_MULTI_UNLOCK();
return (error);
}
@@ -2646,8 +2631,6 @@ inp_set_multicast_if(struct inpcb *inp, struct sockopt *sopt)
/*
* Atomically set source filters on a socket for an IPv4 multicast group.
- *
- * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held.
*/
static int
inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
@@ -2694,6 +2677,7 @@ inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
* Take the INP write lock.
* Check if this socket is a member of this group.
*/
+ IN_MULTI_LOCK();
imo = inp_findmoptions(inp);
idx = imo_match_group(imo, ifp, &gsa->sa);
if (idx == -1 || imo->imo_mfilters == NULL) {
@@ -2778,7 +2762,6 @@ inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
goto out_imf_rollback;
INP_WLOCK_ASSERT(inp);
- IN_MULTI_LOCK();
/*
* Begin state merge transaction at IGMP layer.
@@ -2789,7 +2772,7 @@ inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
if (error) {
CTR1(KTR_IGMPV3, "%s: failed to merge inm state", __func__);
IN_MULTI_LIST_UNLOCK();
- goto out_in_multi_locked;
+ goto out_imf_rollback;
}
CTR1(KTR_IGMPV3, "%s: doing igmp downcall", __func__);
@@ -2798,10 +2781,6 @@ inp_set_source_filters(struct inpcb *inp, struct sockopt *sopt)
if (error)
CTR1(KTR_IGMPV3, "%s: failed igmp downcall", __func__);
-out_in_multi_locked:
-
- IN_MULTI_UNLOCK();
-
out_imf_rollback:
if (error)
imf_rollback(imf);
@@ -2812,6 +2791,7 @@ out_imf_rollback:
out_inp_locked:
INP_WUNLOCK(inp);
+ IN_MULTI_UNLOCK();
return (error);
}
diff --git a/sys/netinet6/in6_mcast.c b/sys/netinet6/in6_mcast.c
index 5557a7c76564..c0e6d2dcb650 100644
--- a/sys/netinet6/in6_mcast.c
+++ b/sys/netinet6/in6_mcast.c
@@ -2052,6 +2052,7 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sopt)
*/
(void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
+ IN6_MULTI_LOCK();
imo = in6p_findmoptions(inp);
idx = im6o_match_group(imo, ifp, &gsa->sa);
if (idx == -1) {
@@ -2171,10 +2172,6 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Begin state merge transaction at MLD layer.
*/
- in_pcbref(inp);
- INP_WUNLOCK(inp);
- IN6_MULTI_LOCK();
-
if (is_new) {
error = in6_joingroup_locked(ifp, &gsa->sin6.sin6_addr, imf,
&inm, 0);
@@ -2204,10 +2201,6 @@ in6p_join_group(struct inpcb *inp, struct sockopt *sopt)
IN6_MULTI_LIST_UNLOCK();
}
- IN6_MULTI_UNLOCK();
- INP_WLOCK(inp);
- if (in_pcbrele_wlocked(inp))
- return (ENXIO);
if (error) {
im6f_rollback(imf);
if (is_new)
@@ -2232,6 +2225,7 @@ out_im6o_free:
out_in6p_locked:
INP_WUNLOCK(inp);
+ IN6_MULTI_UNLOCK();
in6m_release_list_deferred(&inmh);
return (error);
}
@@ -2381,6 +2375,7 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Find the membership in the membership array.
*/
+ IN6_MULTI_LOCK();
imo = in6p_findmoptions(inp);
idx = im6o_match_group(imo, ifp, &gsa->sa);
if (idx == -1) {
@@ -2429,10 +2424,6 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *sopt)
/*
* Begin state merge transaction at MLD layer.
*/
- in_pcbref(inp);
- INP_WUNLOCK(inp);
- IN6_MULTI_LOCK();
-
if (is_final) {
/*
* Give up the multicast address record to which
@@ -2456,11 +2447,6 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *sopt)
IN6_MULTI_LIST_UNLOCK();
}
- IN6_MULTI_UNLOCK();
- INP_WLOCK(inp);
- if (in_pcbrele_wlocked(inp))
- return (ENXIO);
-
if (error)
im6f_rollback(imf);
else
@@ -2483,6 +2469,7 @@ in6p_leave_group(struct inpcb *inp, struct sockopt *sopt)
out_in6p_locked:
INP_WUNLOCK(inp);
+ IN6_MULTI_UNLOCK();
return (error);
}
@@ -2528,8 +2515,6 @@ in6p_set_multicast_if(struct inpcb *inp, struct sockopt *sopt)
/*
* Atomically set source filters on a socket for an IPv6 multicast group.
- *
- * SMPng: NOTE: Potentially calls malloc(M_WAITOK) with Giant held.
*/
static int
in6p_set_source_filters(struct inpcb *inp, struct sockopt *sopt)