kernel/linux.git/net, branch linux-4.20.y

missing barriers in some of unix_sock ->addr and ->path accesses

2019-03-19T12:11:55+00:00

[ Upstream commit ae3b564179bfd06f32d051b9e5d72ce4b2a07c37 ] Several u->addr and u->path users are not holding any locks in common with unix_bind(). unix_state_lock() is useless for those purposes. u->addr is assign-once and *(u->addr) is fully set up by the time we set u->addr (all under unix_table_lock). u->path is also set in the same critical area, also before setting u->addr, and any unix_sock with ->path filled will have non-NULL ->addr. So setting ->addr with smp_store_release() is all we need for those "lockless" users - just have them fetch ->addr with smp_load_acquire() and don't even bother looking at ->path if they see NULL ->addr. Users of ->addr and ->path fall into several classes now: 1) ones that do smp_load_acquire(u->addr) and access *(u->addr) and u->path only if smp_load_acquire() has returned non-NULL. 2) places holding unix_table_lock. These are guaranteed that *(u->addr) is seen fully initialized. If unix_sock is in one of the "bound" chains, so's ->path. 3) unix_sock_destructor() using ->addr is safe. All places that set u->addr are guaranteed to have seen all stores *(u->addr) while holding a reference to u and unix_sock_destructor() is called when (atomic) refcount hits zero. 4) unix_release_sock() using ->path is safe. unix_bind() is serialized wrt unix_release() (normally - by struct file refcount), and for the instances that had ->path set by unix_bind() unix_release_sock() comes from unix_release(), so they are fine. Instances that had it set in unix_stream_connect() either end up attached to a socket (in unix_accept()), in which case the call chain to unix_release_sock() and serialization are the same as in the previous case, or they never get accept'ed and unix_release_sock() is called when the listener is shut down and its queue gets purged. In that case the listener's queue lock provides the barriers needed - unix_stream_connect() shoves our unix_sock into listener's queue under that lock right after having set ->path and eventual unix_release_sock() caller picks them from that queue under the same lock right before calling unix_release_sock(). 5) unix_find_other() use of ->path is pointless, but safe - it happens with successful lookup by (abstract) name, so ->path.dentry is guaranteed to be NULL there. earlier-variant-reviewed-by: "Paul E. McKenney" Signed-off-by: Al Viro Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/smc: fix smc_poll in SMC_INIT state

2019-03-19T12:11:55+00:00

[ Upstream commit d7cf4a3bf3a83c977a29055e1c4ffada7697b31f ] smc_poll() returns with mask bit EPOLLPRI if the connection urg_state is SMC_URG_VALID. Since SMC_URG_VALID is zero, smc_poll signals EPOLLPRI errorneously if called in state SMC_INIT before the connection is created, for instance in a non-blocking connect scenario. This patch switches to non-zero values for the urg states. Reviewed-by: Karsten Graul Fixes: de8474eb9d50 ("net/smc: urgent data support") Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: route: enforce RCU protection in ip6_route_check_nh_onlink()

2019-03-19T12:11:55+00:00

[ Upstream commit bf1dc8bad1d42287164d216d8efb51c5cd381b18 ] We need a RCU critical section around rt6_info->from deference, and proper annotation. Fixes: 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: route: enforce RCU protection in rt6_update_exception_stamp_rt()

2019-03-19T12:11:55+00:00

[ Upstream commit 193f3685d0546b0cea20c99894aadb70098e47bf ] We must access rt6_info->from under RCU read lock: move the dereference under such lock, with proper annotation. v1 -> v2: - avoid using multiple, racy, fetch operations for rt->from Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: route: purge exception on removal

2019-03-19T12:11:54+00:00

[ Upstream commit f5b51fe804ec2a6edce0f8f6b11ea57283f5857b ] When a netdevice is unregistered, we flush the relevant exception via rt6_sync_down_dev() -> fib6_ifdown() -> fib6_del() -> fib6_del_route(). Finally, we end-up calling rt6_remove_exception(), where we release the relevant dst, while we keep the references to the related fib6_info and dev. Such references should be released later when the dst will be destroyed. There are a number of caches that can keep the exception around for an unlimited amount of time - namely dst_cache, possibly even socket cache. As a result device registration may hang, as demonstrated by this script: ip netns add cl ip netns add rt ip netns add srv ip netns exec rt sysctl -w net.ipv6.conf.all.forwarding=1 ip link add name cl_veth type veth peer name cl_rt_veth ip link set dev cl_veth netns cl ip -n cl link set dev cl_veth up ip -n cl addr add dev cl_veth 2001::2/64 ip -n cl route add default via 2001::1 ip -n cl link add tunv6 type ip6tnl mode ip6ip6 local 2001::2 remote 2002::1 hoplimit 64 dev cl_veth ip -n cl link set tunv6 up ip -n cl addr add 2013::2/64 dev tunv6 ip link set dev cl_rt_veth netns rt ip -n rt link set dev cl_rt_veth up ip -n rt addr add dev cl_rt_veth 2001::1/64 ip link add name rt_srv_veth type veth peer name srv_veth ip link set dev srv_veth netns srv ip -n srv link set dev srv_veth up ip -n srv addr add dev srv_veth 2002::1/64 ip -n srv route add default via 2002::2 ip -n srv link add tunv6 type ip6tnl mode ip6ip6 local 2002::1 remote 2001::2 hoplimit 64 dev srv_veth ip -n srv link set tunv6 up ip -n srv addr add 2013::1/64 dev tunv6 ip link set dev rt_srv_veth netns rt ip -n rt link set dev rt_srv_veth up ip -n rt addr add dev rt_srv_veth 2002::2/64 ip netns exec srv netserver & sleep 0.1 ip netns exec cl ping6 -c 4 2013::1 ip netns exec cl netperf -H 2013::1 -t TCP_STREAM -l 3 & sleep 1 ip -n rt link set dev rt_srv_veth mtu 1400 wait %2 ip -n cl link del cl_veth This commit addresses the issue purging all the references held by the exception at time, as we currently do for e.g. ipv6 pcpu dst entries. v1 -> v2: - re-order the code to avoid accessing dst and net after dst_dev_put() Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: Set rtm_table to RT_TABLE_COMPAT for ipv6 for tables > 255

2019-03-19T12:11:54+00:00

[ Upstream commit 97f0082a0592212fc15d4680f5a4d80f79a1687c ] Set rtm_table to RT_TABLE_COMPAT for ipv6 for tables > 255 to keep legacy software happy. This is similar to what was done for ipv4 in commit 709772e6e065 ("net: Fix routing tables with id > 255 for legacy software"). Signed-off-by: Kalash Nainwal Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/x25: fix a race in x25_bind()

2019-03-19T12:11:54+00:00

[ Upstream commit 797a22bd5298c2674d927893f46cadf619dad11d ] syzbot was able to trigger another soft lockup [1] I first thought it was the O(N^2) issue I mentioned in my prior fix (f657d22ee1f "net/x25: do not hold the cpu too long in x25_new_lci()"), but I eventually found that x25_bind() was not checking SOCK_ZAPPED state under socket lock protection. This means that multiple threads can end up calling x25_insert_socket() for the same socket, and corrupt x25_list [1] watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz-executor.2:10492] Modules linked in: irq event stamp: 27515 hardirqs last enabled at (27514): [] trace_hardirqs_on_thunk+0x1a/0x1c hardirqs last disabled at (27515): [] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (32): [] x25_get_neigh+0xa3/0xd0 net/x25/x25_link.c:336 softirqs last disabled at (34): [] x25_find_socket+0x23/0x140 net/x25/af_x25.c:341 CPU: 0 PID: 10492 Comm: syz-executor.2 Not tainted 5.0.0-rc7+ #88 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x50 kernel/kcov.c:97 Code: f4 ff ff ff e8 11 9f ea ff 48 c7 05 12 fb e5 08 00 00 00 00 e9 c8 e9 ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 <48> 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 38 0c 92 7e 81 e2 RSP: 0018:ffff88806e94fc48 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffff1100d84dac5 RBX: 0000000000000001 RCX: ffffc90006197000 RDX: 0000000000040000 RSI: ffffffff86324bf3 RDI: ffff88806c26d628 RBP: ffff88806e94fc48 R08: ffff88806c1c6500 R09: fffffbfff1282561 R10: fffffbfff1282560 R11: ffffffff89412b03 R12: ffff88806c26d628 R13: ffff888090455200 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f3a107e4700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3a107e3db8 CR3: 00000000a5544000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __x25_find_socket net/x25/af_x25.c:327 [inline] x25_find_socket+0x7d/0x140 net/x25/af_x25.c:342 x25_new_lci net/x25/af_x25.c:355 [inline] x25_connect+0x380/0xde0 net/x25/af_x25.c:784 __sys_connect+0x266/0x330 net/socket.c:1662 __do_sys_connect net/socket.c:1673 [inline] __se_sys_connect net/socket.c:1670 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1670 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e29 Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3a107e3c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e29 RDX: 0000000000000012 RSI: 0000000020000200 RDI: 0000000000000005 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a107e46d4 R13: 00000000004be362 R14: 00000000004ceb98 R15: 00000000ffffffff Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10493 Comm: syz-executor.3 Not tainted 5.0.0-rc7+ #88 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline] RIP: 0010:queued_write_lock_slowpath+0x143/0x290 kernel/locking/qrwlock.c:86 Code: 4c 8d 2c 01 41 83 c7 03 41 0f b6 45 00 41 38 c7 7c 08 84 c0 0f 85 0c 01 00 00 8b 03 3d 00 01 00 00 74 1a f3 90 41 0f b6 55 00 <41> 38 d7 7c eb 84 d2 74 e7 48 89 df e8 cc aa 4e 00 eb dd be 04 00 RSP: 0018:ffff888085c47bd8 EFLAGS: 00000206 RAX: 0000000000000300 RBX: ffffffff89412b00 RCX: 1ffffffff1282560 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff89412b00 RBP: ffff888085c47c70 R08: 1ffffffff1282560 R09: fffffbfff1282561 R10: fffffbfff1282560 R11: ffffffff89412b03 R12: 00000000000000ff R13: fffffbfff1282560 R14: 1ffff11010b88f7d R15: 0000000000000003 FS: 00007fdd04086700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdd04064db8 CR3: 0000000090be0000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: queued_write_lock include/asm-generic/qrwlock.h:104 [inline] do_raw_write_lock+0x1d6/0x290 kernel/locking/spinlock_debug.c:203 __raw_write_lock_bh include/linux/rwlock_api_smp.h:204 [inline] _raw_write_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:312 x25_insert_socket+0x21/0xe0 net/x25/af_x25.c:267 x25_bind+0x273/0x340 net/x25/af_x25.c:703 __sys_bind+0x23f/0x290 net/socket.c:1481 __do_sys_bind net/socket.c:1492 [inline] __se_sys_bind net/socket.c:1490 [inline] __x64_sys_bind+0x73/0xb0 net/socket.c:1490 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e29 Fixes: 90c27297a9bf ("X.25 remove bkl in bind") Signed-off-by: Eric Dumazet Cc: andrew hendry Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: repaired skbs must init their tso_segs

2019-03-19T12:11:54+00:00

[ Upstream commit bf50b606cfd85ac8d3d0adb711f3e22204059848 ] syzbot reported a WARN_ON(!tcp_skb_pcount(skb)) in tcp_send_loss_probe() [1] This was caused by TCP_REPAIR sent skbs that inadvertenly were missing a call to tcp_init_tso_segs() [1] WARNING: CPU: 1 PID: 0 at net/ipv4/tcp_output.c:2534 tcp_send_loss_probe+0x771/0x8a0 net/ipv4/tcp_output.c:2534 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.0.0-rc7+ #77 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 panic+0x2cb/0x65c kernel/panic.c:214 __warn.cold+0x20/0x45 kernel/panic.c:571 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:tcp_send_loss_probe+0x771/0x8a0 net/ipv4/tcp_output.c:2534 Code: 88 fc ff ff 4c 89 ef e8 ed 75 c8 fb e9 c8 fc ff ff e8 43 76 c8 fb e9 63 fd ff ff e8 d9 75 c8 fb e9 94 f9 ff ff e8 bf 03 91 fb <0f> 0b e9 7d fa ff ff e8 b3 03 91 fb 0f b6 1d 37 43 7a 03 31 ff 89 RSP: 0018:ffff8880ae907c60 EFLAGS: 00010206 RAX: ffff8880a989c340 RBX: 0000000000000000 RCX: ffffffff85dedbdb RDX: 0000000000000100 RSI: ffffffff85dee0b1 RDI: 0000000000000005 RBP: ffff8880ae907c90 R08: ffff8880a989c340 R09: ffffed10147d1ae1 R10: ffffed10147d1ae0 R11: ffff8880a3e8d703 R12: ffff888091b90040 R13: ffff8880a3e8d540 R14: 0000000000008000 R15: ffff888091b90860 tcp_write_timer_handler+0x5c0/0x8a0 net/ipv4/tcp_timer.c:583 tcp_write_timer+0x10e/0x1d0 net/ipv4/tcp_timer.c:607 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694 __do_softirq+0x266/0x95a kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 Code: ff ff ff 48 89 c7 48 89 45 d8 e8 59 0c a1 fa 48 8b 45 d8 e9 ce fe ff ff 48 89 df e8 48 0c a1 fa eb 82 90 90 90 90 90 90 fb f4 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 RSP: 0018:ffff8880a98afd78 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff1125061 RBX: ffff8880a989c340 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880a989cbbc RBP: ffff8880a98afda8 R08: ffff8880a989c340 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff889282f8 R14: 0000000000000001 R15: 0000000000000000 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 default_idle_call+0x36/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x386/0x570 kernel/sched/idle.c:262 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353 start_secondary+0x404/0x5c0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 79861919b889 ("tcp: fix TCP_REPAIR xmit queue setup") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Andrey Vagin Cc: Soheil Hassas Yeganeh Cc: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: flower: insert new filter to idr after setting its mask

2019-03-19T12:11:54+00:00

[ Upstream commit ecb3dea400d3beaf611ce76ac7a51d4230492cf2 ] When adding new filter to flower classifier, fl_change() inserts it to handle_idr before initializing filter extensions and assigning it a mask. Normally this ordering doesn't matter because all flower classifier ops callbacks assume rtnl lock protection. However, when filter has an action that doesn't have its kernel module loaded, rtnl lock is released before call to request_module(). During this time the filter can be accessed bu concurrent task before its initialization is completed, which can lead to a crash. Example case of NULL pointer dereference in concurrent dump: Task 1 Task 2 tc_new_tfilter() fl_change() idr_alloc_u32(fnew) fl_set_parms() tcf_exts_validate() tcf_action_init() tcf_action_init_1() rtnl_unlock() request_module() ... rtnl_lock() tc_dump_tfilter() tcf_chain_dump() fl_walk() idr_get_next_ul() tcf_node_dump() tcf_fill_node() fl_dump() mask = &f->mask->key; <- NULL ptr rtnl_lock() Extension initialization and mask assignment don't depend on fnew->handle that is allocated by idr_alloc_u32(). Move idr allocation code after action creation and mask assignment in fl_change() to prevent concurrent access to not fully initialized filter when rtnl lock is released to load action module. Fixes: 01683a146999 ("net: sched: refactor flower walk to iterate over idr") Signed-off-by: Vlad Buslov Reviewed-by: Roi Dayan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: handle inet_csk_reqsk_queue_add() failures

2019-03-19T12:11:53+00:00

[ Upstream commit 9d3e1368bb45893a75a5dfb7cd21fdebfa6b47af ] Commit 7716682cc58e ("tcp/dccp: fix another race at listener dismantle") let inet_csk_reqsk_queue_add() fail, and adjusted {tcp,dccp}_check_req() accordingly. However, TFO and syncookies weren't modified, thus leaking allocated resources on error. Contrary to tcp_check_req(), in both syncookies and TFO cases, we need to drop the request socket. Also, since the child socket is created with inet_csk_clone_lock(), we have to unlock it and drop an extra reference (->sk_refcount is initially set to 2 and inet_csk_reqsk_queue_add() drops only one ref). For TFO, we also need to revert the work done by tcp_try_fastopen() (with reqsk_fastopen_remove()). Fixes: 7716682cc58e ("tcp/dccp: fix another race at listener dismantle") Signed-off-by: Guillaume Nault Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman