1. 30 Aug, 2017 4 commits
    • Eric Dumazet's avatar
      ipv4: fix NULL dereference in free_fib_info_rcu() · 114414b8
      Eric Dumazet authored
      
      [ Upstream commit 187e5b3a ]
      
      If fi->fib_metrics could not be allocated in fib_create_info()
      we attempt to dereference a NULL pointer in free_fib_info_rcu() :
      
          m = fi->fib_metrics;
          if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
                  kfree(m);
      
      Before my recent patch, we used to call kfree(NULL) and nothing wrong
      happened.
      
      Instead of using RCU to defer freeing while we are under memory stress,
      it seems better to take immediate action.
      
      This was reported by syzkaller team.
      
      Fixes: 3fb07daf ("ipv4: add reference counting to metrics")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      114414b8
    • Eric Dumazet's avatar
      dccp: defer ccid_hc_tx_delete() at dismantle time · c207ec46
      Eric Dumazet authored
      
      [ Upstream commit 120e9dab ]
      
      syszkaller team reported another problem in DCCP [1]
      
      Problem here is that the structure holding RTO timer
      (ccid2_hc_tx_rto_expire() handler) is freed too soon.
      
      We can not use del_timer_sync() to cancel the timer
      since this timer wants to grab socket lock (that would risk a dead lock)
      
      Solution is to defer the freeing of memory when all references to
      the socket were released. Socket timers do own a reference, so this
      should fix the issue.
      
      [1]
      
      ==================================================================
      BUG: KASAN: use-after-free in ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144
      Read of size 4 at addr ffff8801d2660540 by task kworker/u4:7/3365
      
      CPU: 1 PID: 3365 Comm: kworker/u4:7 Not tainted 4.13.0-rc4+ #3
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Workqueue: events_unbound call_usermodehelper_exec_work
      Call Trace:
       <IRQ>
       __dump_stack lib/dump_stack.c:16 [inline]
       dump_stack+0x194/0x257 lib/dump_stack.c:52
       print_address_description+0x73/0x250 mm/kasan/report.c:252
       kasan_report_error mm/kasan/report.c:351 [inline]
       kasan_report+0x24e/0x340 mm/kasan/report.c:409
       __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
       ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144
       call_timer_fn+0x233/0x830 kernel/time/timer.c:1268
       expire_timers kernel/time/timer.c:1307 [inline]
       __run_timers+0x7fd/0xb90 kernel/time/timer.c:1601
       run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
       __do_softirq+0x2f5/0xba3 kernel/softirq.c:284
       invoke_softirq kernel/softirq.c:364 [inline]
       irq_exit+0x1cc/0x200 kernel/softirq.c:405
       exiting_irq arch/x86/include/asm/apic.h:638 [inline]
       smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:1044
       apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:702
      RIP: 0010:arch_local_irq_enable arch/x86/include/asm/paravirt.h:824 [inline]
      RIP: 0010:__raw_write_unlock_irq include/linux/rwlock_api_smp.h:267 [inline]
      RIP: 0010:_raw_write_unlock_irq+0x56/0x70 kernel/locking/spinlock.c:343
      RSP: 0018:ffff8801cd50eaa8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10
      RAX: dffffc0000000000 RBX: ffffffff85a090c0 RCX: 0000000000000006
      RDX: 1ffffffff0b595f3 RSI: 1ffff1003962f989 RDI: ffffffff85acaf98
      RBP: ffff8801cd50eab0 R08: 0000000000000001 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cc96ea60
      R13: dffffc0000000000 R14: ffff8801cc96e4c0 R15: ffff8801cc96e4c0
       </IRQ>
       release_task+0xe9e/0x1a40 kernel/exit.c:220
       wait_task_zombie kernel/exit.c:1162 [inline]
       wait_consider_task+0x29b8/0x33c0 kernel/exit.c:1389
       do_wait_thread kernel/exit.c:1452 [inline]
       do_wait+0x441/0xa90 kernel/exit.c:1523
       kernel_wait4+0x1f5/0x370 kernel/exit.c:1665
       SYSC_wait4+0x134/0x140 kernel/exit.c:1677
       SyS_wait4+0x2c/0x40 kernel/exit.c:1673
       call_usermodehelper_exec_sync kernel/kmod.c:286 [inline]
       call_usermodehelper_exec_work+0x1a0/0x2c0 kernel/kmod.c:323
       process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2097
       worker_thread+0x223/0x1860 kernel/workqueue.c:2231
       kthread+0x35e/0x430 kernel/kthread.c:231
       ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:425
      
      Allocated by task 21267:
       save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
       kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
       kmem_cache_alloc+0x127/0x750 mm/slab.c:3561
       ccid_new+0x20e/0x390 net/dccp/ccid.c:151
       dccp_hdlr_ccid+0x27/0x140 net/dccp/feat.c:44
       __dccp_feat_activate+0x142/0x2a0 net/dccp/feat.c:344
       dccp_feat_activate_values+0x34e/0xa90 net/dccp/feat.c:1538
       dccp_rcv_request_sent_state_process net/dccp/input.c:472 [inline]
       dccp_rcv_state_process+0xed1/0x1620 net/dccp/input.c:677
       dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679
       sk_backlog_rcv include/net/sock.h:911 [inline]
       __release_sock+0x124/0x360 net/core/sock.c:2269
       release_sock+0xa4/0x2a0 net/core/sock.c:2784
       inet_wait_for_connect net/ipv4/af_inet.c:557 [inline]
       __inet_stream_connect+0x671/0xf00 net/ipv4/af_inet.c:643
       inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:682
       SYSC_connect+0x204/0x470 net/socket.c:1642
       SyS_connect+0x24/0x30 net/socket.c:1623
       entry_SYSCALL_64_fastpath+0x1f/0xbe
      
      Freed by task 3049:
       save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
       __cache_free mm/slab.c:3503 [inline]
       kmem_cache_free+0x77/0x280 mm/slab.c:3763
       ccid_hc_tx_delete+0xc5/0x100 net/dccp/ccid.c:190
       dccp_destroy_sock+0x1d1/0x2b0 net/dccp/proto.c:225
       inet_csk_destroy_sock+0x166/0x3f0 net/ipv4/inet_connection_sock.c:833
       dccp_done+0xb7/0xd0 net/dccp/proto.c:145
       dccp_time_wait+0x13d/0x300 net/dccp/minisocks.c:72
       dccp_rcv_reset+0x1d1/0x5b0 net/dccp/input.c:160
       dccp_rcv_state_process+0x8fc/0x1620 net/dccp/input.c:663
       dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679
       sk_backlog_rcv include/net/sock.h:911 [inline]
       __sk_receive_skb+0x33e/0xc00 net/core/sock.c:521
       dccp_v4_rcv+0xef1/0x1c00 net/dccp/ipv4.c:871
       ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
       NF_HOOK include/linux/netfilter.h:248 [inline]
       ip_local_deliver+0x1ce/0x6d0 net/ipv4/ip_input.c:257
       dst_input include/net/dst.h:477 [inline]
       ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397
       NF_HOOK include/linux/netfilter.h:248 [inline]
       ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488
       __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4417
       __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4455
       process_backlog+0x203/0x740 net/core/dev.c:5130
       napi_poll net/core/dev.c:5527 [inline]
       net_rx_action+0x792/0x1910 net/core/dev.c:5593
       __do_softirq+0x2f5/0xba3 kernel/softirq.c:284
      
      The buggy address belongs to the object at ffff8801d2660100
       which belongs to the cache ccid2_hc_tx_sock of size 1240
      The buggy address is located 1088 bytes inside of
       1240-byte region [ffff8801d2660100, ffff8801d26605d8)
      The buggy address belongs to the page:
      page:ffffea0007499800 count:1 mapcount:0 mapping:ffff8801d2660100 index:0x0 compound_mapcount: 0
      flags: 0x200000000008100(slab|head)
      raw: 0200000000008100 ffff8801d2660100 0000000000000000 0000000100000005
      raw: ffffea00075271a0 ffffea0007538820 ffff8801d3aef9c0 0000000000000000
      page dumped because: kasan: bad access detected
      
      Memory state around the buggy address:
       ffff8801d2660400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
       ffff8801d2660480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
      >ffff8801d2660500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
       ffff8801d2660580: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
       ffff8801d2660600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
      ==================================================================
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c207ec46
    • Eric Dumazet's avatar
      dccp: purge write queue in dccp_destroy_sock() · c65eca7d
      Eric Dumazet authored
      
      [ Upstream commit 7749d4ff ]
      
      syzkaller reported that DCCP could have a non empty
      write queue at dismantle time.
      
      WARNING: CPU: 1 PID: 2953 at net/core/stream.c:199 sk_stream_kill_queues+0x3ce/0x520 net/core/stream.c:199
      Kernel panic - not syncing: panic_on_warn set ...
      
      CPU: 1 PID: 2953 Comm: syz-executor0 Not tainted 4.13.0-rc4+ #2
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:16 [inline]
       dump_stack+0x194/0x257 lib/dump_stack.c:52
       panic+0x1e4/0x417 kernel/panic.c:180
       __warn+0x1c4/0x1d9 kernel/panic.c:541
       report_bug+0x211/0x2d0 lib/bug.c:183
       fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190
       do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
       do_trap+0x260/0x390 arch/x86/kernel/traps.c:273
       do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310
       do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
       invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:846
      RIP: 0010:sk_stream_kill_queues+0x3ce/0x520 net/core/stream.c:199
      RSP: 0018:ffff8801d182f108 EFLAGS: 00010297
      RAX: ffff8801d1144140 RBX: ffff8801d13cb280 RCX: 0000000000000000
      RDX: 0000000000000000 RSI: ffffffff85137b00 RDI: ffff8801d13cb280
      RBP: ffff8801d182f148 R08: 0000000000000001 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d13cb4d0
      R13: ffff8801d13cb3b8 R14: ffff8801d13cb300 R15: ffff8801d13cb3b8
       inet_csk_destroy_sock+0x175/0x3f0 net/ipv4/inet_connection_sock.c:835
       dccp_close+0x84d/0xc10 net/dccp/proto.c:1067
       inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
       sock_release+0x8d/0x1e0 net/socket.c:597
       sock_close+0x16/0x20 net/socket.c:1126
       __fput+0x327/0x7e0 fs/file_table.c:210
       ____fput+0x15/0x20 fs/file_table.c:246
       task_work_run+0x18a/0x260 kernel/task_work.c:116
       exit_task_work include/linux/task_work.h:21 [inline]
       do_exit+0xa32/0x1b10 kernel/exit.c:865
       do_group_exit+0x149/0x400 kernel/exit.c:969
       get_signal+0x7e8/0x17e0 kernel/signal.c:2330
       do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808
       exit_to_usermode_loop+0x21c/0x2d0 arch/x86/entry/common.c:157
       prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
       syscall_return_slowpath+0x3a7/0x450 arch/x86/entry/common.c:263
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c65eca7d
    • Eric Dumazet's avatar
      af_key: do not use GFP_KERNEL in atomic contexts · f0cd9201
      Eric Dumazet authored
      
      [ Upstream commit 36f41f8f ]
      
      pfkey_broadcast() might be called from non process contexts,
      we can not use GFP_KERNEL in these cases [1].
      
      This patch partially reverts commit ba51b6be ("net: Fix RCU splat in
      af_key"), only keeping the GFP_ATOMIC forcing under rcu_read_lock()
      section.
      
      [1] : syzkaller reported :
      
      in_atomic(): 1, irqs_disabled(): 0, pid: 2932, name: syzkaller183439
      3 locks held by syzkaller183439/2932:
       #0:  (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff83b43888>] pfkey_sendmsg+0x4c8/0x9f0 net/key/af_key.c:3649
       #1:  (&pfk->dump_lock){+.+.+.}, at: [<ffffffff83b467f6>] pfkey_do_dump+0x76/0x3f0 net/key/af_key.c:293
       #2:  (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] spin_lock_bh include/linux/spinlock.h:304 [inline]
       #2:  (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] xfrm_policy_walk+0x192/0xa30 net/xfrm/xfrm_policy.c:1028
      CPU: 0 PID: 2932 Comm: syzkaller183439 Not tainted 4.13.0-rc4+ #24
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:16 [inline]
       dump_stack+0x194/0x257 lib/dump_stack.c:52
       ___might_sleep+0x2b2/0x470 kernel/sched/core.c:5994
       __might_sleep+0x95/0x190 kernel/sched/core.c:5947
       slab_pre_alloc_hook mm/slab.h:416 [inline]
       slab_alloc mm/slab.c:3383 [inline]
       kmem_cache_alloc+0x24b/0x6e0 mm/slab.c:3559
       skb_clone+0x1a0/0x400 net/core/skbuff.c:1037
       pfkey_broadcast_one+0x4b2/0x6f0 net/key/af_key.c:207
       pfkey_broadcast+0x4ba/0x770 net/key/af_key.c:281
       dump_sp+0x3d6/0x500 net/key/af_key.c:2685
       xfrm_policy_walk+0x2f1/0xa30 net/xfrm/xfrm_policy.c:1042
       pfkey_dump_sp+0x42/0x50 net/key/af_key.c:2695
       pfkey_do_dump+0xaa/0x3f0 net/key/af_key.c:299
       pfkey_spddump+0x1a0/0x210 net/key/af_key.c:2722
       pfkey_process+0x606/0x710 net/key/af_key.c:2814
       pfkey_sendmsg+0x4d6/0x9f0 net/key/af_key.c:3650
      sock_sendmsg_nosec net/socket.c:633 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:643
       ___sys_sendmsg+0x755/0x890 net/socket.c:2035
       __sys_sendmsg+0xe5/0x210 net/socket.c:2069
       SYSC_sendmsg net/socket.c:2080 [inline]
       SyS_sendmsg+0x2d/0x50 net/socket.c:2076
       entry_SYSCALL_64_fastpath+0x1f/0xbe
      RIP: 0033:0x445d79
      RSP: 002b:00007f32447c1dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
      RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445d79
      RDX: 0000000000000000 RSI: 000000002023dfc8 RDI: 0000000000000008
      RBP: 0000000000000086 R08: 00007f32447c2700 R09: 00007f32447c2700
      R10: 00007f32447c2700 R11: 0000000000000202 R12: 0000000000000000
      R13: 00007ffe33edec4f R14: 00007f32447c29c0 R15: 0000000000000000
      
      Fixes: ba51b6be ("net: Fix RCU splat in af_key")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Cc: David Ahern <dsa@cumulusnetworks.com>
      Acked-by: default avatarDavid Ahern <dsahern@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f0cd9201
  2. 25 Aug, 2017 21 commits
  3. 16 Aug, 2017 15 commits