kernel.git/net/ipv6/addrconf.c, branch linux-4.11.y

ipv6: dad: don't remove dynamic addresses if link is down

2017-07-21T05:00:07Z

[ Upstream commit ec8add2a4c9df723c94a863b8fcd6d93c472deed ] Currently, when the link for $DEV is down, this command succeeds but the address is removed immediately by DAD (1): ip addr add 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800 In the same situation, this will succeed and not remove the address (2): ip addr add 1111::12/64 dev $DEV ip addr change 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800 The comment in addrconf_dad_begin() when !IF_READY makes it look like this is the intended behavior, but doesn't explain why: * If the device is not ready: * - keep it tentative if it is a permanent address. * - otherwise, kill it. We clearly cannot prevent userspace from doing (2), but we can make (1) work consistently with (2). addrconf_dad_stop() is only called in two cases: if DAD failed, or to skip DAD when the link is down. In that second case, the fix is to avoid deleting the address, like we already do for permanent addresses. Fixes: 3c21edbd1137 ("[IPV6]: Defer IPv6 device initialization until the link becomes ready.") Signed-off-by: Sabrina Dubroca Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: avoid unregistering inet6_dev for loopback

2017-07-21T05:00:05Z

[ Upstream commit 60abc0be96e00ca71bac083215ac91ad2e575096 ] The per netns loopback_dev->ip6_ptr is unregistered and set to NULL when its mtu is set to smaller than IPV6_MIN_MTU, this leads to that we could set rt->rt6i_idev NULL after a rt6_uncached_list_flush_dev() and then crash after another call. In this case we should just bring its inet6_dev down, rather than unregistering it, at least prior to commit 176c39af29bc ("netns: fix addrconf_ifdown kernel panic") we always override the case for loopback. Thanks a lot to Andrey for finding a reliable reproducer. Fixes: 176c39af29bc ("netns: fix addrconf_ifdown kernel panic") Reported-by: Andrey Konovalov Cc: Andrey Konovalov Cc: Daniel Lezcano Cc: David Ahern Signed-off-by: Cong Wang Acked-by: David Ahern Tested-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: fix calling in6_ifa_hold incorrectly for dad work

2017-07-05T12:41:36Z

[ Upstream commit f8a894b218138888542a5058d0e902378fd0d4ec ] Now when starting the dad work in addrconf_mod_dad_work, if the dad work is idle and queued, it needs to hold ifa. The problem is there's one gap in [1], during which if the pending dad work is removed elsewhere. It will miss to hold ifa, but the dad word is still idea and queue. if (!delayed_work_pending(&ifp->dad_work)) in6_ifa_hold(ifp); <--------------[1] mod_delayed_work(addrconf_wq, &ifp->dad_work, delay); An use-after-free issue can be caused by this. Chen Wei found this issue when WARN_ON(!hlist_unhashed(&ifp->addr_lst)) in net6_ifa_finish_destroy was hit because of it. As Hannes' suggestion, this patch is to fix it by holding ifa first in addrconf_mod_dad_work, then calling mod_delayed_work and putting ifa if the dad_work is already in queue. Note that this patch did not choose to fix it with: if (!mod_delayed_work(delay)) in6_ifa_hold(ifp); As with it, when delay == 0, dad_work would be scheduled immediately, all addrconf_mod_dad_work(0) callings had to be moved under ifp->lock. Reported-by: Wei Chen Suggested-by: Hannes Frederic Sowa Acked-by: Hannes Frederic Sowa Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf

2017-05-14T12:06:02Z

[ Upstream commit 242d3a49a2a1a71d8eb9f953db1bcaa9d698ce00 ] For each netns (except init_net), we initialize its null entry in 3 places: 1) The template itself, as we use kmemdup() 2) Code around dst_init_metrics() in ip6_route_net_init() 3) ip6_route_dev_notify(), which is supposed to initialize it after loopback registers Unfortunately the last one still happens in a wrong order because we expect to initialize net->ipv6.ip6_null_entry->rt6i_idev to net->loopback_dev's idev, thus we have to do that after we add idev to loopback. However, this notifier has priority == 0 same as ipv6_dev_notf, and ipv6_dev_notf is registered after ip6_route_dev_notifier so it is called actually after ip6_route_dev_notifier. This is similar to commit 2f460933f58e ("ipv6: initialize route null entry in addrconf_init()") which fixes init_net. Fix it by picking a smaller priority for ip6_route_dev_notifier. Also, we have to release the refcnt accordingly when unregistering loopback_dev because device exit functions are called before subsys exit functions. Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: initialize route null entry in addrconf_init()

2017-05-14T12:06:02Z

[ Upstream commit 2f460933f58eee3393aba64f0f6d14acb08d1724 ] Andrey reported a crash on init_net.ipv6.ip6_null_entry->rt6i_idev since it is always NULL. This is clearly wrong, we have code to initialize it to loopback_dev, unfortunately the order is still not correct. loopback_dev is registered very early during boot, we lose a chance to re-initialize it in notifier. addrconf_init() is called after ip6_route_init(), which means we have no chance to correct it. Fix it by moving this initialization explicitly after ipv6_add_dev(init_net.loopback_dev) in addrconf_init(). Reported-by: Andrey Konovalov Signed-off-by: Cong Wang Tested-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: ipv6: Do not duplicate DAD on link up

2017-05-14T12:06:01Z

[ Upstream commit 6d717134a1a6e1b34a7d0d70e953037bc2642046 ] Andrey reported a warning triggered by the rcu code: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5911 at lib/debugobjects.c:289 debug_print_object+0x175/0x210 ODEBUG: activate active (active state 1) object type: rcu_head hint: (null) Modules linked in: CPU: 1 PID: 5911 Comm: a.out Not tainted 4.11.0-rc8+ #271 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x192/0x22d lib/dump_stack.c:52 __warn+0x19f/0x1e0 kernel/panic.c:549 warn_slowpath_fmt+0xe0/0x120 kernel/panic.c:564 debug_print_object+0x175/0x210 lib/debugobjects.c:286 debug_object_activate+0x574/0x7e0 lib/debugobjects.c:442 debug_rcu_head_queue kernel/rcu/rcu.h:75 __call_rcu.constprop.76+0xff/0x9c0 kernel/rcu/tree.c:3229 call_rcu_sched+0x12/0x20 kernel/rcu/tree.c:3288 rt6_rcu_free net/ipv6/ip6_fib.c:158 rt6_release+0x1ea/0x290 net/ipv6/ip6_fib.c:188 fib6_del_route net/ipv6/ip6_fib.c:1461 fib6_del+0xa42/0xdc0 net/ipv6/ip6_fib.c:1500 __ip6_del_rt+0x100/0x160 net/ipv6/route.c:2174 ip6_del_rt+0x140/0x1b0 net/ipv6/route.c:2187 __ipv6_ifa_notify+0x269/0x780 net/ipv6/addrconf.c:5520 addrconf_ifdown+0xe60/0x1a20 net/ipv6/addrconf.c:3672 ... Andrey's reproducer program runs in a very tight loop, calling 'unshare -n' and then spawning 2 sets of 14 threads running random ioctl calls. The relevant networking sequence: 1. New network namespace created via unshare -n - ip6tnl0 device is created in down state 2. address added to ip6tnl0 - equivalent to ip -6 addr add dev ip6tnl0 fd00::bb/1 - DAD is started on the address and when it completes the host route is inserted into the FIB 3. ip6tnl0 is brought up - the new fixup_permanent_addr function restarts DAD on the address 4. exit namespace - teardown / cleanup sequence starts - once in a blue moon, lo teardown appears to happen BEFORE teardown of ip6tunl0 + down on 'lo' removes the host route from the FIB since the dst->dev for the route is loobback + host route added to rcu callback list * rcu callback has not run yet, so rt is NOT on the gc list so it has NOT been marked obsolete 5. in parallel to 4. worker_thread runs addrconf_dad_completed - DAD on the address on ip6tnl0 completes - calls ipv6_ifa_notify which inserts the host route All of that happens very quickly. The result is that a host route that has been deleted from the IPv6 FIB and added to the RCU list is re-inserted into the FIB. The exit namespace eventually gets to cleaning up ip6tnl0 which removes the host route from the FIB again, calls the rcu function for cleanup -- and triggers the double rcu trace. The root cause is duplicate DAD on the address -- steps 2 and 3. Arguably, DAD should not be started in step 2. The interface is in the down state, so it can not really send out requests for the address which makes starting DAD pointless. Since the second DAD was introduced by a recent change, seems appropriate to use it for the Fixes tag and have the fixup function only start DAD for addresses in the PREDAD state which occurs in addrconf_ifdown if the address is retained. Big thanks to Andrey for isolating a reliable reproducer for this problem. Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Reported-by: Andrey Konovalov Signed-off-by: David Ahern Tested-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: ipv6: regenerate host route if moved to gc list

2017-04-25T18:04:44Z

Taking down the loopback device wreaks havoc on IPv6 routing. By extension, taking down a VRF device wreaks havoc on its table. Dmitry and Andrey both reported heap out-of-bounds reports in the IPv6 FIB code while running syzkaller fuzzer. The root cause is a dead dst that is on the garbage list gets reinserted into the IPv6 FIB. While on the gc (or perhaps when it gets added to the gc list) the dst->next is set to an IPv4 dst. A subsequent walk of the ipv6 tables causes the out-of-bounds access. Andrey's reproducer was the key to getting to the bottom of this. With IPv6, host routes for an address have the dst->dev set to the loopback device. When the 'lo' device is taken down, rt6_ifdown initiates a walk of the fib evicting routes with the 'lo' device which means all host routes are removed. That process moves the dst which is attached to an inet6_ifaddr to the gc list and marks it as dead. The recent change to keep global IPv6 addresses added a new function, fixup_permanent_addr, that is called on admin up. That function restarts dad for an inet6_ifaddr and when it completes the host route attached to it is inserted into the fib. Since the route was marked dead and moved to the gc list, re-inserting the route causes the reported out-of-bounds accesses. If the device with the address is taken down or the address is removed, the WARN_ON in fib6_del is triggered. All of those faults are fixed by regenerating the host route if the existing one has been moved to the gc list, something that can be determined by checking if the rt6i_ref counter is 0. Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Reported-by: Dmitry Vyukov Reported-by: Andrey Konovalov Signed-off-by: David Ahern Acked-by: Martin KaFai Lau Acked-by: Eric Dumazet Signed-off-by: David S. Miller

ipv6: Fix idev->addr_list corruption

2017-04-12T17:23:39Z

addrconf_ifdown() removes elements from the idev->addr_list without holding the idev->lock. If this happens while the loop in __ipv6_dev_get_saddr() is handling the same element, that function ends up in an infinite loop: NMI watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [test:1719] Call Trace: ipv6_get_saddr_eval+0x13c/0x3a0 __ipv6_dev_get_saddr+0xe4/0x1f0 ipv6_dev_get_saddr+0x1b4/0x204 ip6_dst_lookup_tail+0xcc/0x27c ip6_dst_lookup_flow+0x38/0x80 udpv6_sendmsg+0x708/0xba8 sock_sendmsg+0x18/0x30 SyS_sendto+0xb8/0xf8 syscall_common+0x34/0x58 Fixes: 6a923934c33 (Revert "ipv6: Revert optional address flusing on ifdown.") Signed-off-by: Rabin Vincent Acked-by: David Ahern Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2017-03-05T01:31:39Z

Pull networking fixes from David Miller: 1) Fix double-free in batman-adv, from Sven Eckelmann. 2) Fix packet stats for fast-RX path, from Joannes Berg. 3) Netfilter's ip_route_me_harder() doesn't handle request sockets properly, fix from Florian Westphal. 4) Fix sendmsg deadlock in rxrpc, from David Howells. 5) Add missing RCU locking to transport hashtable scan, from Xin Long. 6) Fix potential packet loss in mlxsw driver, from Ido Schimmel. 7) Fix race in NAPI handling between poll handlers and busy polling, from Eric Dumazet. 8) TX path in vxlan and geneve need proper RCU locking, from Jakub Kicinski. 9) SYN processing in DCCP and TCP need to disable BH, from Eric Dumazet. 10) Properly handle net_enable_timestamp() being invoked from IRQ context, also from Eric Dumazet. 11) Fix crash on device-tree systems in xgene driver, from Alban Bedel. 12) Do not call sk_free() on a locked socket, from Arnaldo Carvalho de Melo. 13) Fix use-after-free in netvsc driver, from Dexuan Cui. 14) Fix max MTU setting in bonding driver, from WANG Cong. 15) xen-netback hash table can be allocated from softirq context, so use GFP_ATOMIC. From Anoob Soman. 16) Fix MAC address change bug in bgmac driver, from Hari Vyas. 17) strparser needs to destroy strp_wq on module exit, from WANG Cong. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (69 commits) strparser: destroy workqueue on module exit sfc: fix IPID endianness in TSOv2 sfc: avoid max() in array size rds: remove unnecessary returned value check rxrpc: Fix potential NULL-pointer exception nfp: correct DMA direction in XDP DMA sync nfp: don't tell FW about the reserved buffer space net: ethernet: bgmac: mac address change bug net: ethernet: bgmac: init sequence bug xen-netback: don't vfree() queues under spinlock xen-netback: keep a local pointer for vif in backend_disconnect() netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails netfilter: nft_set_rbtree: incorrect assumption on lower interval lookups netfilter: nf_conntrack_sip: fix wrong memory initialisation can: flexcan: fix typo in comment can: usb_8dev: Fix memory leak of priv->cmd_msg_buffer can: gs_usb: fix coding style can: gs_usb: Don't use stack memory for USB transfers ixgbe: Limit use of 2K buffers on architectures with 256B or larger cache lines ixgbe: update the rss key on h/w, when ethtool ask for it ...

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32Z

Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar