xavi/android_kernel_m2note/net/core/neighbour.c, branch ng-7.1.2

neigh: fix use-after-free read in pneigh_get_next

2019-07-18T18:42:45+00:00

[ Upstream commit f3e92cb8e2eb8c27d109e6fd73d3a69a8c09e288 ] Nine years ago, I added RCU handling to neighbours, not pneighbours. (pneigh are not commonly used) Unfortunately I missed that /proc dump operations would use a common entry and exit point : neigh_seq_start() and neigh_seq_stop() We need to read_lock(tbl->lock) or risk use-after-free while iterating the pneigh structures. We might later convert pneigh to RCU and revert this patch. sysbot reported : BUG: KASAN: use-after-free in pneigh_get_next.isra.0+0x24b/0x280 net/core/neighbour.c:3158 Read of size 8 at addr ffff888097f2a700 by task syz-executor.0/9825 CPU: 1 PID: 9825 Comm: syz-executor.0 Not tainted 5.2.0-rc4+ #32 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 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 pneigh_get_next.isra.0+0x24b/0x280 net/core/neighbour.c:3158 neigh_seq_next+0xdb/0x210 net/core/neighbour.c:3240 seq_read+0x9cf/0x1110 fs/seq_file.c:258 proc_reg_read+0x1fc/0x2c0 fs/proc/inode.c:221 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 kernel_readv fs/splice.c:359 [inline] default_file_splice_read+0x475/0x890 fs/splice.c:414 do_splice_to+0x127/0x180 fs/splice.c:877 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:954 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4592c9 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4aab51dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000004592c9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000246 R12: 00007f4aab51e6d4 R13: 00000000004c689d R14: 00000000004db828 R15: 00000000ffffffff Allocated by task 9827: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 __do_kmalloc mm/slab.c:3660 [inline] __kmalloc+0x15c/0x740 mm/slab.c:3669 kmalloc include/linux/slab.h:552 [inline] pneigh_lookup+0x19c/0x4a0 net/core/neighbour.c:731 arp_req_set_public net/ipv4/arp.c:1010 [inline] arp_req_set+0x613/0x720 net/ipv4/arp.c:1026 arp_ioctl+0x652/0x7f0 net/ipv4/arp.c:1226 inet_ioctl+0x2a0/0x340 net/ipv4/af_inet.c:926 sock_do_ioctl+0xd8/0x2f0 net/socket.c:1043 sock_ioctl+0x3ed/0x780 net/socket.c:1194 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9824: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kfree+0xcf/0x220 mm/slab.c:3755 pneigh_ifdown_and_unlock net/core/neighbour.c:812 [inline] __neigh_ifdown+0x236/0x2f0 net/core/neighbour.c:356 neigh_ifdown+0x20/0x30 net/core/neighbour.c:372 arp_ifdown+0x1d/0x21 net/ipv4/arp.c:1274 inetdev_destroy net/ipv4/devinet.c:319 [inline] inetdev_event+0xa14/0x11f0 net/ipv4/devinet.c:1544 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95 __raw_notifier_call_chain kernel/notifier.c:396 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1749 call_netdevice_notifiers_extack net/core/dev.c:1761 [inline] call_netdevice_notifiers net/core/dev.c:1775 [inline] rollback_registered_many+0x9b9/0xfc0 net/core/dev.c:8178 rollback_registered+0x109/0x1d0 net/core/dev.c:8220 unregister_netdevice_queue net/core/dev.c:9267 [inline] unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9260 unregister_netdevice include/linux/netdevice.h:2631 [inline] __tun_detach+0xd8a/0x1040 drivers/net/tun.c:724 tun_detach drivers/net/tun.c:741 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3451 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888097f2a700 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 0 bytes inside of 64-byte region [ffff888097f2a700, ffff888097f2a740) The buggy address belongs to the page: page:ffffea00025fca80 refcount:1 mapcount:0 mapping:ffff8880aa400340 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000250d548 ffffea00025726c8 ffff8880aa400340 raw: 0000000000000000 ffff888097f2a000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888097f2a600: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff888097f2a680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff888097f2a700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888097f2a780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888097f2a800: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour") Change-Id: I2e2d47ab5ba1c740515c3a0ed93c96f43bc1696d Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: fix deadlock while clearing neighbor proxy table

2019-05-03T16:57:35+00:00

commit 53b76cdf7e8fecec1d09e38aad2f8579882591a8 upstream. When coming from ndisc_netdev_event() in net/ipv6/ndisc.c, neigh_ifdown() is called with &nd_tbl, locking this while clearing the proxy neighbor entries when eg. deleting an interface. Calling the table's pndisc_destructor() with the lock still held, however, can cause a deadlock: When a multicast listener is available an IGMP packet of type ICMPV6_MGM_REDUCTION may be sent out. When reaching ip6_finish_output2(), if no neighbor entry for the target address is found, __neigh_create() is called with &nd_tbl, which it'll want to lock. Move the elements into their own list, then unlock the table and perform the destruction. Change-Id: I3e0bb9f41948210b1419fa35b3537d2a14afdd18 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199289 Fixes: 6fd6ce2056de ("ipv6: Do not depend on rt->n in ip6_finish_output2().") Signed-off-by: Wolfgang Bumiller Signed-off-by: David S. Miller [bwh: Backported to 3.16: - Move the (useless) call to release_net() as well - Adjust context] Signed-off-by: Ben Hutchings

BACKPORT: neigh: probe application via netlink in NUD_PROBE

2019-05-02T13:37:42+00:00

iproute2 arpd seems to expect this as there's code and comments to handle netlink probes with NUD_PROBE set. It is used to flush the arpd cached mappings. opennhrp instead turns off unicast probes (so it can handle all neighbour discovery). Without this change it will not see NUD_PROBE probes and cannot reconfirm the mapping. Thus currently neigh entry will just fail and can cause few packets dropped until broadcast discovery is restarted. Earlier discussion on the subject: http://marc.info/?t=139305877100001&r=1&w=2 Change-Id: I35664f8731fe319a2325c16a5243571e21aeb73d Signed-off-by: Timo Teräs Signed-off-by: David S. Miller [syphyr: Backported to 3.10 and 3.4] Signed-off-by: L.W. Reek

neigh: do not modify unlinked entries

2019-05-02T12:30:26+00:00

commit 2c51a97f76d20ebf1f50fef908b986cb051fdff9 upstream. The lockless lookups can return entry that is unlinked. Sometimes they get reference before last neigh_cleanup_and_release, sometimes they do not need reference. Later, any modification attempts may result in the following problems: 1. entry is not destroyed immediately because neigh_update can start the timer for dead entry, eg. on change to NUD_REACHABLE state. As result, entry lives for some time but is invisible and out of control. 2. __neigh_event_send can run in parallel with neigh_destroy while refcnt=0 but if timer is started and expired refcnt can reach 0 for second time leading to second neigh_destroy and possible crash. Thanks to Eric Dumazet and Ying Xue for their work and analyze on the __neigh_event_send change. Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour") Fixes: a263b3093641 ("ipv4: Make neigh lookups directly in output packet path.") Fixes: 6fd6ce2056de ("ipv6: Do not depend on rt->n in ip6_finish_output2().") Change-Id: I09181080d56c2e343603412bc7ad390eee87be8f Cc: Eric Dumazet Cc: Ying Xue Signed-off-by: Julian Anastasov Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Luis Henriques

net: core: neighbour: Change the print format for addresses

2017-08-24T15:33:45+00:00

Print format %p displays the kernel address while bypassing the kptr_restrict sysctl settings. Change the print format for addresses from %p to %pK. If kptr_restrict is enabled, addresses are printed as zeroes. To view the actual addresses, disable kptr_restrict by - echo 0 > /proc/sys/kernel/kptr_restrict Bug: 37340687, 37341313 CRs-Fixed: 987041 Change-Id: I2eb33c63168ab26818dfdb3e11315f2ce8f24fa5 Signed-off-by: Subash Abhinov Kasiviswanathan Signed-off-by: Naveen Ramaraj

net: neigh: guard against NULL solicit() method

2017-07-04T10:11:25+00:00

commit 48481c8fa16410ffa45939b13b6c53c2ca609e5f upstream. Dmitry posted a nice reproducer of a bug triggering in neigh_probe() when dereferencing a NULL neigh->ops->solicit method. This can happen for arp_direct_ops/ndisc_direct_ops and similar, which can be used for NUD_NOARP neighbours (created when dev->header_ops is NULL). Admin can then force changing nud_state to some other state that would fire neigh timer. Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau

neigh: Better handling of transition to NUD_PROBE state

2017-04-11T08:59:58+00:00

[1] When entering NUD_PROBE state via neigh_update(), perhaps received from userspace, correctly (re)initialize the probes count to zero. This is useful for forcing revalidation of a neighbor (for example if the host is attempting to do DNA [IPv4 4436, IPv6 6059]). [2] Notify listeners when a neighbor goes into NUD_PROBE state. By sending notifications on entry to NUD_PROBE state listeners get more timely warnings of imminent connectivity issues. The current notifications on entry to NUD_STALE have somewhat limited usefulness: NUD_STALE is a perfectly normal state, as is NUD_DELAY, whereas notifications on entry to NUD_FAILURE come after a neighbor reachability problem has been confirmed (typically after three probes). Change-Id: I1d01d40ef3bc4753b0eaa79da2b27235425b1934 Signed-off-by: Erik Kline Acked-By: Lorenzo Colitti Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

random: sprinkle e/f/prandom in places that deplete entropy often

2016-09-10T10:06:52+00:00

first commit

2016-08-15T02:19:42+00:00