kernel.git/net/ipv4/igmp.c, branch linux-3.18.y

net: igmp: add a missing rcu locking section

2018-02-16T19:14:41Z

[ Upstream commit e7aadb27a5415e8125834b84a74477bfbee4eff5 ] Newly added igmpv3_get_srcaddr() needs to be called under rcu lock. Timer callbacks do not ensure this locking. ============================= WARNING: suspicious RCU usage 4.15.0+ #200 Not tainted ----------------------------- ./include/linux/inetdevice.h:216 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 3 locks held by syzkaller616973/4074: #0: (&mm->mmap_sem){++++}, at: [<00000000bfce669e>] __do_page_fault+0x32d/0xc90 arch/x86/mm/fault.c:1355 #1: ((&im->timer)){+.-.}, at: [<00000000619d2f71>] lockdep_copy_map include/linux/lockdep.h:178 [inline] #1: ((&im->timer)){+.-.}, at: [<00000000619d2f71>] call_timer_fn+0x1c6/0x820 kernel/time/timer.c:1316 #2: (&(&im->lock)->rlock){+.-.}, at: [<000000005f833c5c>] spin_lock_bh include/linux/spinlock.h:315 [inline] #2: (&(&im->lock)->rlock){+.-.}, at: [<000000005f833c5c>] igmpv3_send_report+0x98/0x5b0 net/ipv4/igmp.c:600 stack backtrace: CPU: 0 PID: 4074 Comm: syzkaller616973 Not tainted 4.15.0+ #200 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4592 __in_dev_get_rcu include/linux/inetdevice.h:216 [inline] igmpv3_get_srcaddr net/ipv4/igmp.c:329 [inline] igmpv3_newpack+0xeef/0x12e0 net/ipv4/igmp.c:389 add_grhead.isra.27+0x235/0x300 net/ipv4/igmp.c:432 add_grec+0xbd3/0x1170 net/ipv4/igmp.c:565 igmpv3_send_report+0xd5/0x5b0 net/ipv4/igmp.c:605 igmp_send_report+0xc43/0x1050 net/ipv4/igmp.c:722 igmp_timer_expire+0x322/0x5c0 net/ipv4/igmp.c:831 call_timer_fn+0x228/0x820 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers+0x7ee/0xb70 kernel/time/timer.c:1666 run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 invoke_softirq kernel/softirq.c:365 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:541 [inline] smp_apic_timer_interrupt+0x16b/0x700 arch/x86/kernel/apic/apic.c:1052 apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:938 Fixes: a46182b00290 ("net: igmp: Use correct source address on IGMPv3 reports") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: igmp: fix source address check for IGMPv3 reports

2018-01-31T13:46:14Z

[ Upstream commit ad23b750933ea7bf962678972a286c78a8fa36aa ] Commit "net: igmp: Use correct source address on IGMPv3 reports" introduced a check to validate the source address of locally generated IGMPv3 packets. Instead of checking the local interface address directly, it uses inet_ifa_match(fl4->saddr, ifa), which checks if the address is on the local subnet (or equal to the point-to-point address if used). This breaks for point-to-point interfaces, so check against ifa->ifa_local directly. Cc: Kevin Cernekee Fixes: a46182b00290 ("net: igmp: Use correct source address on IGMPv3 reports") Reported-by: Sebastian Gottschall Signed-off-by: Felix Fietkau Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: igmp: Use correct source address on IGMPv3 reports

2018-01-02T19:04:58Z

[ Upstream commit a46182b00290839fa3fa159d54fd3237bd8669f0 ] Closing a multicast socket after the final IPv4 address is deleted from an interface can generate a membership report that uses the source IP from a different interface. The following test script, run from an isolated netns, reproduces the issue: #!/bin/bash ip link add dummy0 type dummy ip link add dummy1 type dummy ip link set dummy0 up ip link set dummy1 up ip addr add 10.1.1.1/24 dev dummy0 ip addr add 192.168.99.99/24 dev dummy1 tcpdump -U -i dummy0 & socat EXEC:"sleep 2" \ UDP4-DATAGRAM:239.101.1.68:8889,ip-add-membership=239.0.1.68:10.1.1.1 & sleep 1 ip addr del 10.1.1.1/24 dev dummy0 sleep 5 kill %tcpdump RFC 3376 specifies that the report must be sent with a valid IP source address from the destination subnet, or from address 0.0.0.0. Add an extra check to make sure this is the case. Signed-off-by: Kevin Cernekee Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv4: igmp: guard against silly MTU values

2018-01-02T19:04:58Z

[ Upstream commit b5476022bbada3764609368f03329ca287528dc8 ] IPv4 stack reacts to changes to small MTU, by disabling itself under RTNL. But there is a window where threads not using RTNL can see a wrong device mtu. This can lead to surprises, in igmp code where it is assumed the mtu is suitable. Fix this by reading device mtu once and checking IPv4 minimal MTU. This patch adds missing IPV4_MIN_MTU define, to not abuse ETH_MIN_MTU anymore. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

igmp: add a missing spin_lock_init()

2017-07-05T12:35:13Z

[ Upstream commit b4846fc3c8559649277e3e4e6b5cec5348a8d208 ] Andrey reported a lockdep warning on non-initialized spinlock: INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x292/0x395 lib/dump_stack.c:52 register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755 ? 0xffffffffa0000000 __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255 lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855 __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135 _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175 spin_lock_bh ./include/linux/spinlock.h:304 ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076 igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194 ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736 We miss a spin_lock_init() in igmpv3_add_delrec(), probably because previously we never use it on this code path. Since we already unlink it from the global mc_tomb list, it is probably safe not to acquire this spinlock here. It does not harm to have it although, to avoid conditional locking. Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()") Reported-by: Andrey Konovalov Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

igmp: acquire pmc lock for ip_mc_clear_src()

2017-07-05T12:35:13Z

[ Upstream commit c38b7d327aafd1e3ad7ff53eefac990673b65667 ] Andrey reported a use-after-free in add_grec(): for (psf = *psf_list; psf; psf = psf_next) { ... psf_next = psf->sf_next; where the struct ip_sf_list's were already freed by: kfree+0xe8/0x2b0 mm/slub.c:3882 ip_mc_clear_src+0x69/0x1c0 net/ipv4/igmp.c:2078 ip_mc_dec_group+0x19a/0x470 net/ipv4/igmp.c:1618 ip_mc_drop_socket+0x145/0x230 net/ipv4/igmp.c:2609 inet_release+0x4e/0x1c0 net/ipv4/af_inet.c:411 sock_release+0x8d/0x1e0 net/socket.c:597 sock_close+0x16/0x20 net/socket.c:1072 This happens because we don't hold pmc->lock in ip_mc_clear_src() and a parallel mr_ifc_timer timer could jump in and access them. The RCU lock is there but it is merely for pmc itself, this spinlock could actually ensure we don't access them in parallel. Thanks to Eric and Long for discussion on this bug. Reported-by: Andrey Konovalov Cc: Eric Dumazet Cc: Xin Long Signed-off-by: Cong Wang Reviewed-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: mld: fix add_grhead skb_over_panic for devs with large MTUs

2014-11-16T21:55:06Z

It has been reported that generating an MLD listener report on devices with large MTUs (e.g. 9000) and a high number of IPv6 addresses can trigger a skb_over_panic(): skbuff: skb_over_panic: text:ffffffff80612a5d len:3776 put:20 head:ffff88046d751000 data:ffff88046d751010 tail:0xed0 end:0xec0 dev:port1 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:100! invalid opcode: 0000 [#1] SMP Modules linked in: ixgbe(O) CPU: 3 PID: 0 Comm: swapper/3 Tainted: G O 3.14.23+ #4 [...] Call Trace: [] ? skb_put+0x3a/0x3b [] ? add_grhead+0x45/0x8e [] ? add_grec+0x394/0x3d4 [] ? mld_ifc_timer_expire+0x195/0x20d [] ? mld_dad_timer_expire+0x45/0x45 [] ? call_timer_fn.isra.29+0x12/0x68 [] ? run_timer_softirq+0x163/0x182 [] ? __do_softirq+0xe0/0x21d [] ? irq_exit+0x4e/0xd3 [] ? smp_apic_timer_interrupt+0x3b/0x46 [] ? apic_timer_interrupt+0x6a/0x70 mld_newpack() skb allocations are usually requested with dev->mtu in size, since commit 72e09ad107e7 ("ipv6: avoid high order allocations") we have changed the limit in order to be less likely to fail. However, in MLD/IGMP code, we have some rather ugly AVAILABLE(skb) macros, which determine if we may end up doing an skb_put() for adding another record. To avoid possible fragmentation, we check the skb's tailroom as skb->dev->mtu - skb->len, which is a wrong assumption as the actual max allocation size can be much smaller. The IGMP case doesn't have this issue as commit 57e1ab6eaddc ("igmp: refine skb allocations") stores the allocation size in the cb[]. Set a reserved_tailroom to make it fit into the MTU and use skb_availroom() helper instead. This also allows to get rid of igmp_skb_size(). Reported-by: Wei Liu Fixes: 72e09ad107e7 ("ipv6: avoid high order allocations") Signed-off-by: Daniel Borkmann Cc: Eric Dumazet Cc: Hannes Frederic Sowa Cc: David L Stevens Acked-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

ipv4: igmp: fix v3 general query drop monitor false positive

2014-10-06T21:14:54Z

In case we find a general query with non-zero number of sources, we are dropping the skb as it's malformed. RFC3376, section 4.1.8. Number of Sources (N): This number is zero in a General Query or a Group-Specific Query, and non-zero in a Group-and-Source-Specific Query. Therefore, reflect that by using kfree_skb() instead of consume_skb(). Fixes: d679c5324d9a ("igmp: avoid drop_monitor false positives") Signed-off-by: Daniel Borkmann Acked-by: Eric Dumazet Signed-off-by: David S. Miller

ipv4: implement igmp_qrv sysctl to tune igmp robustness variable

2014-09-05T05:26:14Z

As in IPv6 people might increase the igmp query robustness variable to make sure unsolicited state change reports aren't lost on the network. Add and document this new knob to igmp code. RFCs allow tuning this parameter back to first IGMP RFC, so we also use this setting for all counters, including source specific multicast. Also take over sysctl value when upping the interface and don't reuse the last one seen on the interface. Cc: Flavio Leitner Signed-off-by: Hannes Frederic Sowa Acked-by: Flavio Leitner Signed-off-by: David S. Miller

net/ipv4/igmp.c: Replace rcu_dereference() with rcu_access_pointer()

2014-08-22T19:23:10Z

The "rcu_dereference()" call is used directly in a condition. Since its return value is never dereferenced it is recommended to use "rcu_access_pointer()" instead of "rcu_dereference()". Therefore, this patch makes the replacement. The following Coccinelle semantic patch was used: @@ @@ ( if( (<+... - rcu_dereference + rcu_access_pointer (...) ...+>)) {...} | while( (<+... - rcu_dereference + rcu_access_pointer (...) ...+>)) {...} ) Signed-off-by: Andreea-Cristina Bernat Signed-off-by: David S. Miller