The branch main has been updated by wma:
URL:
https://cgit.FreeBSD.org/src/commit/?id=65634ae748e7f6b7b9f11e8838c65060c3f31347
commit 65634ae748e7f6b7b9f11e8838c65060c3f31347
Author: Wojciech Macek <w...@freebsd.org>
AuthorDate: 2021-04-23 03:57:03 +0000
Commit: Wojciech Macek <w...@freebsd.org>
CommitDate: 2021-05-11 10:34:20 +0000
mroute: fix race condition during mrouter shutting down
There is a race condition between V_ip_mrouter de-init
and ip_mforward handling. It might happen that mrouted
is cleaned up after V_ip_mrouter check and before
processing packet in ip_mforward.
Use epoch call aproach, similar to IPSec which also handles
such case.
Reported by: Damien Deville
Obtained from: Stormshield
Reviewed by: mw
Differential Revision: https://reviews.freebsd.org/D29946
---
sys/netinet/ip_input.c | 9 ++++++++-
sys/netinet/ip_mroute.c | 2 ++
sys/netinet/ip_mroute.h | 5 +++++
sys/netinet/ip_output.c | 5 +++++
4 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index a85f8ac7b567..43d375c2385f 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -82,6 +82,7 @@ __FBSDID("$FreeBSD$");
#include <machine/in_cksum.h>
#include <netinet/ip_carp.h>
#include <netinet/in_rss.h>
+#include <netinet/ip_mroute.h>
#include <netipsec/ipsec_support.h>
@@ -451,6 +452,7 @@ ip_direct_input(struct mbuf *m)
void
ip_input(struct mbuf *m)
{
+ MROUTER_RLOCK_TRACKER;
struct rm_priotracker in_ifa_tracker;
struct ip *ip = NULL;
struct in_ifaddr *ia = NULL;
@@ -743,6 +745,7 @@ passin:
return;
}
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+ MROUTER_RLOCK();
if (V_ip_mrouter) {
/*
* If we are acting as a multicast router, all
@@ -753,6 +756,7 @@ passin:
* must be discarded, else it may be accepted below.
*/
if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
+ MROUTER_RUNLOCK();
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
@@ -763,10 +767,13 @@ passin:
* all multicast IGMP packets, whether or not this
* host belongs to their destination groups.
*/
- if (ip->ip_p == IPPROTO_IGMP)
+ if (ip->ip_p == IPPROTO_IGMP) {
+ MROUTER_RUNLOCK();
goto ours;
+ }
IPSTAT_INC(ips_forward);
}
+ MROUTER_RUNLOCK();
/*
* Assume the packet is for us, to avoid prematurely taking
* a lock on the in_multi hash. Protocols must perform
diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index b66fe8df0793..8ecc983ea58f 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -720,6 +720,8 @@ X_ip_mrouter_done(void)
ip_mrouter_cnt--;
V_mrt_api_config = 0;
+ MROUTER_WAIT();
+
VIF_LOCK();
/*
diff --git a/sys/netinet/ip_mroute.h b/sys/netinet/ip_mroute.h
index 054eb921d3df..6ef99c0172f3 100644
--- a/sys/netinet/ip_mroute.h
+++ b/sys/netinet/ip_mroute.h
@@ -355,6 +355,11 @@ extern int (*ip_mrouter_get)(struct socket *, struct
sockopt *);
extern int (*ip_mrouter_done)(void);
extern int (*mrt_ioctl)(u_long, caddr_t, int);
+#define MROUTER_RLOCK_TRACKER struct epoch_tracker mrouter_et
+#define MROUTER_RLOCK() epoch_enter_preempt(net_epoch_preempt,
&mrouter_et)
+#define MROUTER_RUNLOCK() epoch_exit_preempt(net_epoch_preempt,
&mrouter_et)
+#define MROUTER_WAIT() epoch_wait_preempt(net_epoch_preempt)
+
#endif /* _KERNEL */
#endif /* _NETINET_IP_MROUTE_H_ */
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 405490e890c0..f913a2591fcc 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -83,6 +83,7 @@ __FBSDID("$FreeBSD$");
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
+#include <netinet/ip_mroute.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
@@ -319,6 +320,7 @@ int
ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
struct ip_moptions *imo, struct inpcb *inp)
{
+ MROUTER_RLOCK_TRACKER;
struct rm_priotracker in_ifa_tracker;
struct ip *ip;
struct ifnet *ifp = NULL; /* keep compiler happy */
@@ -613,6 +615,7 @@ again:
* above, will be forwarded by the ip_input() routine,
* if necessary.
*/
+ MROUTER_RLOCK();
if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
/*
* If rsvp daemon is not running, do not
@@ -624,10 +627,12 @@ again:
imo = NULL;
if (ip_mforward &&
ip_mforward(ip, ifp, m, imo) != 0) {
+ MROUTER_RUNLOCK();
m_freem(m);
goto done;
}
}
+ MROUTER_RUNLOCK();
}
/*
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