linux.git/net/ipv6, branch v5.1 Linux kernel source tree ipv6: A few fixes on dereferencing rt->from 2019-05-01T21:17:54+00:00 Martin KaFai Lau kafai@fb.com 2019-04-30T17:45:12+00:00 886b7a50100a50f1cbd08a6f8ec5884dfbe082dc It is a followup after the fix in commit 9c69a1320515 ("route: Avoid crash from dereferencing NULL rt->from") rt6_do_redirect(): 1. NULL checking is needed on rt->from because a parallel fib6_info delete could happen that sets rt->from to NULL. (e.g. rt6_remove_exception() and fib6_drop_pcpu_from()). 2. fib6_info_hold() is not enough. Same reason as (1). Meaning, holding dst->__refcnt cannot ensure rt->from is not NULL or rt->from->fib6_ref is not 0. Instead of using fib6_info_hold_safe() which ip6_rt_cache_alloc() is already doing, this patch chooses to extend the rcu section to keep "from" dereference-able after checking for NULL. inet6_rtm_getroute(): 1. NULL checking is also needed on rt->from for a similar reason. Note that inet6_rtm_getroute() is using RTNL_FLAG_DOIT_UNLOCKED. Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Wei Wang <weiwan@google.com> Reviewed-by: David Ahern <dsahern@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
It is a followup after the fix in
commit 9c69a1320515 ("route: Avoid crash from dereferencing NULL rt->from")

rt6_do_redirect():
1. NULL checking is needed on rt->from because a parallel
   fib6_info delete could happen that sets rt->from to NULL.
   (e.g. rt6_remove_exception() and fib6_drop_pcpu_from()).

2. fib6_info_hold() is not enough.  Same reason as (1).
   Meaning, holding dst->__refcnt cannot ensure
   rt->from is not NULL or rt->from->fib6_ref is not 0.

   Instead of using fib6_info_hold_safe() which ip6_rt_cache_alloc()
   is already doing, this patch chooses to extend the rcu section
   to keep "from" dereference-able after checking for NULL.

inet6_rtm_getroute():
1. NULL checking is also needed on rt->from for a similar reason.
   Note that inet6_rtm_getroute() is using RTNL_FLAG_DOIT_UNLOCKED.

Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Wei Wang <weiwan@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6: fix races in ip6_dst_destroy() 2019-05-01T03:38:38+00:00 Eric Dumazet edumazet@google.com 2019-04-28T19:22:25+00:00 0e2338749192ce0e52e7174c5352f627632f478a We had many syzbot reports that seem to be caused by use-after-free of struct fib6_info. ip6_dst_destroy(), fib6_drop_pcpu_from() and rt6_remove_exception() are writers vs rt->from, and use non consistent synchronization among themselves. Switching to xchg() will solve the issues with no possible lockdep issues. BUG: KASAN: user-memory-access in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:747 [inline] BUG: KASAN: user-memory-access in fib6_info_release include/net/ip6_fib.h:294 [inline] BUG: KASAN: user-memory-access in fib6_info_release include/net/ip6_fib.h:292 [inline] BUG: KASAN: user-memory-access in fib6_drop_pcpu_from net/ipv6/ip6_fib.c:927 [inline] BUG: KASAN: user-memory-access in fib6_purge_rt+0x4f6/0x670 net/ipv6/ip6_fib.c:960 Write of size 4 at addr 0000000000ffffb4 by task syz-executor.1/7649 CPU: 0 PID: 7649 Comm: syz-executor.1 Not tainted 5.1.0-rc6+ #183 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 kasan_report.cold+0x5/0x40 mm/kasan/report.c:321 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_write+0x14/0x20 mm/kasan/common.c:108 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:747 [inline] fib6_info_release include/net/ip6_fib.h:294 [inline] fib6_info_release include/net/ip6_fib.h:292 [inline] fib6_drop_pcpu_from net/ipv6/ip6_fib.c:927 [inline] fib6_purge_rt+0x4f6/0x670 net/ipv6/ip6_fib.c:960 fib6_del_route net/ipv6/ip6_fib.c:1813 [inline] fib6_del+0xac2/0x10a0 net/ipv6/ip6_fib.c:1844 fib6_clean_node+0x3a8/0x590 net/ipv6/ip6_fib.c:2006 fib6_walk_continue+0x495/0x900 net/ipv6/ip6_fib.c:1928 fib6_walk+0x9d/0x100 net/ipv6/ip6_fib.c:1976 fib6_clean_tree+0xe0/0x120 net/ipv6/ip6_fib.c:2055 __fib6_clean_all+0x118/0x2a0 net/ipv6/ip6_fib.c:2071 fib6_clean_all+0x2b/0x40 net/ipv6/ip6_fib.c:2082 rt6_sync_down_dev+0x134/0x150 net/ipv6/route.c:4057 rt6_disable_ip+0x27/0x5f0 net/ipv6/route.c:4062 addrconf_ifdown+0xa2/0x1220 net/ipv6/addrconf.c:3705 addrconf_notify+0x19a/0x2260 net/ipv6/addrconf.c:3630 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1753 call_netdevice_notifiers_extack net/core/dev.c:1765 [inline] call_netdevice_notifiers net/core/dev.c:1779 [inline] dev_close_many+0x33f/0x6f0 net/core/dev.c:1522 rollback_registered_many+0x43b/0xfd0 net/core/dev.c:8177 rollback_registered+0x109/0x1d0 net/core/dev.c:8242 unregister_netdevice_queue net/core/dev.c:9289 [inline] unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9282 unregister_netdevice include/linux/netdevice.h:2658 [inline] __tun_detach+0xd5b/0x1000 drivers/net/tun.c:727 tun_detach drivers/net/tun.c:744 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3443 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x90a/0x2fa0 kernel/exit.c:876 do_group_exit+0x135/0x370 kernel/exit.c:980 __do_sys_exit_group kernel/exit.c:991 [inline] __se_sys_exit_group kernel/exit.c:989 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458da9 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:00007ffeafc2a6a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001c RCX: 0000000000458da9 RDX: 0000000000412a80 RSI: 0000000000a54ef0 RDI: 0000000000000043 RBP: 00000000004be552 R08: 000000000000000c R09: 000000000004c0d1 R10: 0000000002341940 R11: 0000000000000246 R12: 00000000ffffffff R13: 00007ffeafc2a7f0 R14: 000000000004c065 R15: 00007ffeafc2a800 Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: David Ahern <dsahern@gmail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Wei Wang <weiwan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
We had many syzbot reports that seem to be caused by use-after-free
of struct fib6_info.

ip6_dst_destroy(), fib6_drop_pcpu_from() and rt6_remove_exception()
are writers vs rt->from, and use non consistent synchronization among
themselves.

Switching to xchg() will solve the issues with no possible
lockdep issues.

BUG: KASAN: user-memory-access in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:747 [inline]
BUG: KASAN: user-memory-access in fib6_info_release include/net/ip6_fib.h:294 [inline]
BUG: KASAN: user-memory-access in fib6_info_release include/net/ip6_fib.h:292 [inline]
BUG: KASAN: user-memory-access in fib6_drop_pcpu_from net/ipv6/ip6_fib.c:927 [inline]
BUG: KASAN: user-memory-access in fib6_purge_rt+0x4f6/0x670 net/ipv6/ip6_fib.c:960
Write of size 4 at addr 0000000000ffffb4 by task syz-executor.1/7649

CPU: 0 PID: 7649 Comm: syz-executor.1 Not tainted 5.1.0-rc6+ #183
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
 kasan_report.cold+0x5/0x40 mm/kasan/report.c:321
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_write+0x14/0x20 mm/kasan/common.c:108
 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:747 [inline]
 fib6_info_release include/net/ip6_fib.h:294 [inline]
 fib6_info_release include/net/ip6_fib.h:292 [inline]
 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:927 [inline]
 fib6_purge_rt+0x4f6/0x670 net/ipv6/ip6_fib.c:960
 fib6_del_route net/ipv6/ip6_fib.c:1813 [inline]
 fib6_del+0xac2/0x10a0 net/ipv6/ip6_fib.c:1844
 fib6_clean_node+0x3a8/0x590 net/ipv6/ip6_fib.c:2006
 fib6_walk_continue+0x495/0x900 net/ipv6/ip6_fib.c:1928
 fib6_walk+0x9d/0x100 net/ipv6/ip6_fib.c:1976
 fib6_clean_tree+0xe0/0x120 net/ipv6/ip6_fib.c:2055
 __fib6_clean_all+0x118/0x2a0 net/ipv6/ip6_fib.c:2071
 fib6_clean_all+0x2b/0x40 net/ipv6/ip6_fib.c:2082
 rt6_sync_down_dev+0x134/0x150 net/ipv6/route.c:4057
 rt6_disable_ip+0x27/0x5f0 net/ipv6/route.c:4062
 addrconf_ifdown+0xa2/0x1220 net/ipv6/addrconf.c:3705
 addrconf_notify+0x19a/0x2260 net/ipv6/addrconf.c:3630
 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1753
 call_netdevice_notifiers_extack net/core/dev.c:1765 [inline]
 call_netdevice_notifiers net/core/dev.c:1779 [inline]
 dev_close_many+0x33f/0x6f0 net/core/dev.c:1522
 rollback_registered_many+0x43b/0xfd0 net/core/dev.c:8177
 rollback_registered+0x109/0x1d0 net/core/dev.c:8242
 unregister_netdevice_queue net/core/dev.c:9289 [inline]
 unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9282
 unregister_netdevice include/linux/netdevice.h:2658 [inline]
 __tun_detach+0xd5b/0x1000 drivers/net/tun.c:727
 tun_detach drivers/net/tun.c:744 [inline]
 tun_chr_close+0xe0/0x180 drivers/net/tun.c:3443
 __fput+0x2e5/0x8d0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x90a/0x2fa0 kernel/exit.c:876
 do_group_exit+0x135/0x370 kernel/exit.c:980
 __do_sys_exit_group kernel/exit.c:991 [inline]
 __se_sys_exit_group kernel/exit.c:989 [inline]
 __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
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:00007ffeafc2a6a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000001c RCX: 0000000000458da9
RDX: 0000000000412a80 RSI: 0000000000a54ef0 RDI: 0000000000000043
RBP: 00000000004be552 R08: 000000000000000c R09: 000000000004c0d1
R10: 0000000002341940 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00007ffeafc2a7f0 R14: 000000000004c065 R15: 00007ffeafc2a800

Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: David Ahern <dsahern@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2019-04-30T13:11:10+00:00 David S. Miller davem@davemloft.net 2019-04-30T13:11:10+00:00 b145745fc8d15cf9d45a5c7a8f5dbc4862e17cf2 Steffen Klassert says: ==================== pull request (net): ipsec 2019-04-30 1) Fix an out-of-bound array accesses in __xfrm_policy_unlink. From YueHaibing. 2) Reset the secpath on failure in the ESP GRO handlers to avoid dereferencing an invalid pointer on error. From Myungho Jung. 3) Add and revert a patch that tried to add rcu annotations to netns_xfrm. From Su Yanjun. 4) Wait for rcu callbacks before freeing xfrm6_tunnel_spi_kmem. From Su Yanjun. 5) Fix forgotten vti4 ipip tunnel deregistration. From Jeremy Sowden: 6) Remove some duplicated log messages in vti4. From Jeremy Sowden. 7) Don't use IPSEC_PROTO_ANY when flushing states because this will flush only IPsec portocol speciffic states. IPPROTO_ROUTING states may remain in the lists when doing net exit. Fix this by replacing IPSEC_PROTO_ANY with zero. From Cong Wang. 8) Add length check for UDP encapsulation to fix "Oversized IP packet" warnings on receive side. From Sabrina Dubroca. 9) Fix xfrm interface lookup when the interface is associated to a vrf layer 3 master device. From Martin Willi. 10) Reload header pointers after pskb_may_pull() in _decode_session4(), otherwise we may read from uninitialized memory. 11) Update the documentation about xfrm[46]_gc_thresh, it is not used anymore after the flowcache removal. From Nicolas Dichtel. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> 
Steffen Klassert says:

====================
pull request (net): ipsec 2019-04-30

1) Fix an out-of-bound array accesses in __xfrm_policy_unlink.
   From YueHaibing.

2) Reset the secpath on failure in the ESP GRO handlers
   to avoid dereferencing an invalid pointer on error.
   From Myungho Jung.

3) Add and revert a patch that tried to add rcu annotations
   to netns_xfrm. From Su Yanjun.

4) Wait for rcu callbacks before freeing xfrm6_tunnel_spi_kmem.
   From Su Yanjun.

5) Fix forgotten vti4 ipip tunnel deregistration.
   From Jeremy Sowden:

6) Remove some duplicated log messages in vti4.
   From Jeremy Sowden.

7) Don't use IPSEC_PROTO_ANY when flushing states because
   this will flush only IPsec portocol speciffic states.
   IPPROTO_ROUTING states may remain in the lists when
   doing net exit. Fix this by replacing IPSEC_PROTO_ANY
   with zero. From Cong Wang.

8) Add length check for UDP encapsulation to fix "Oversized IP packet"
   warnings on receive side. From Sabrina Dubroca.

9) Fix xfrm interface lookup when the interface is associated to
   a vrf layer 3 master device. From Martin Willi.

10) Reload header pointers after pskb_may_pull() in _decode_session4(),
    otherwise we may read from uninitialized memory.

11) Update the documentation about xfrm[46]_gc_thresh, it
    is not used anymore after the flowcache removal.
    From Nicolas Dichtel.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6/flowlabel: wait rcu grace period before put_pid() 2019-04-30T03:30:13+00:00 Eric Dumazet edumazet@google.com 2019-04-27T23:49:06+00:00 6c0afef5fb0c27758f4d52b2210c61b6bd8b4470 syzbot was able to catch a use-after-free read in pid_nr_ns() [1] ip6fl_seq_show() seems to use RCU protection, dereferencing fl->owner.pid but fl_free() releases fl->owner.pid before rcu grace period is started. [1] BUG: KASAN: use-after-free in pid_nr_ns+0x128/0x140 kernel/pid.c:407 Read of size 4 at addr ffff888094012a04 by task syz-executor.0/18087 CPU: 0 PID: 18087 Comm: syz-executor.0 Not tainted 5.1.0-rc6+ #89 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:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 pid_nr_ns+0x128/0x140 kernel/pid.c:407 ip6fl_seq_show+0x2f8/0x4f0 net/ipv6/ip6_flowlabel.c:794 seq_read+0xad3/0x1130 fs/seq_file.c:268 proc_reg_read+0x1fe/0x2c0 fs/proc/inode.c:227 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:922 vfs_readv+0xf0/0x160 fs/read_write.c:984 kernel_readv fs/splice.c:358 [inline] default_file_splice_read+0x475/0x890 fs/splice.c:413 do_splice_to+0x12a/0x190 fs/splice.c:876 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:953 do_splice_direct+0x1da/0x2a0 fs/splice.c:1062 do_sendfile+0x597/0xd00 fs/read_write.c:1443 __do_sys_sendfile64 fs/read_write.c:1498 [inline] __se_sys_sendfile64 fs/read_write.c:1490 [inline] __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1490 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458da9 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:00007f300d24bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458da9 RDX: 00000000200000c0 RSI: 0000000000000008 RDI: 0000000000000007 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000005a R11: 0000000000000246 R12: 00007f300d24c6d4 R13: 00000000004c5fa3 R14: 00000000004da748 R15: 00000000ffffffff Allocated by task 17543: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505 slab_post_alloc_hook mm/slab.h:437 [inline] slab_alloc mm/slab.c:3393 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3555 alloc_pid+0x55/0x8f0 kernel/pid.c:168 copy_process.part.0+0x3b08/0x7980 kernel/fork.c:1932 copy_process kernel/fork.c:1709 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2226 __do_sys_clone kernel/fork.c:2333 [inline] __se_sys_clone kernel/fork.c:2327 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2327 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7789: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3499 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3765 put_pid.part.0+0x111/0x150 kernel/pid.c:111 put_pid+0x20/0x30 kernel/pid.c:105 fl_free+0xbe/0xe0 net/ipv6/ip6_flowlabel.c:102 ip6_fl_gc+0x295/0x3e0 net/ipv6/ip6_flowlabel.c:152 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:293 The buggy address belongs to the object at ffff888094012a00 which belongs to the cache pid_2 of size 88 The buggy address is located 4 bytes inside of 88-byte region [ffff888094012a00, ffff888094012a58) The buggy address belongs to the page: page:ffffea0002500480 count:1 mapcount:0 mapping:ffff88809a483080 index:0xffff888094012980 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00018a3508 ffffea0002524a88 ffff88809a483080 raw: ffff888094012980 ffff888094012000 000000010000001b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888094012900: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff888094012980: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc >ffff888094012a00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ^ ffff888094012a80: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff888094012b00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc Fixes: 4f82f45730c6 ("net ip6 flowlabel: Make owner a union of struct pid * and kuid_t") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
syzbot was able to catch a use-after-free read in pid_nr_ns() [1]

ip6fl_seq_show() seems to use RCU protection, dereferencing fl->owner.pid
but fl_free() releases fl->owner.pid before rcu grace period is started.

[1]

BUG: KASAN: use-after-free in pid_nr_ns+0x128/0x140 kernel/pid.c:407
Read of size 4 at addr ffff888094012a04 by task syz-executor.0/18087

CPU: 0 PID: 18087 Comm: syz-executor.0 Not tainted 5.1.0-rc6+ #89
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:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 pid_nr_ns+0x128/0x140 kernel/pid.c:407
 ip6fl_seq_show+0x2f8/0x4f0 net/ipv6/ip6_flowlabel.c:794
 seq_read+0xad3/0x1130 fs/seq_file.c:268
 proc_reg_read+0x1fe/0x2c0 fs/proc/inode.c:227
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_loop_readv_writev fs/read_write.c:688 [inline]
 do_iter_read+0x4a9/0x660 fs/read_write.c:922
 vfs_readv+0xf0/0x160 fs/read_write.c:984
 kernel_readv fs/splice.c:358 [inline]
 default_file_splice_read+0x475/0x890 fs/splice.c:413
 do_splice_to+0x12a/0x190 fs/splice.c:876
 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:953
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1062
 do_sendfile+0x597/0xd00 fs/read_write.c:1443
 __do_sys_sendfile64 fs/read_write.c:1498 [inline]
 __se_sys_sendfile64 fs/read_write.c:1490 [inline]
 __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1490
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
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:00007f300d24bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458da9
RDX: 00000000200000c0 RSI: 0000000000000008 RDI: 0000000000000007
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000005a R11: 0000000000000246 R12: 00007f300d24c6d4
R13: 00000000004c5fa3 R14: 00000000004da748 R15: 00000000ffffffff

Allocated by task 17543:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3393 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3555
 alloc_pid+0x55/0x8f0 kernel/pid.c:168
 copy_process.part.0+0x3b08/0x7980 kernel/fork.c:1932
 copy_process kernel/fork.c:1709 [inline]
 _do_fork+0x257/0xfd0 kernel/fork.c:2226
 __do_sys_clone kernel/fork.c:2333 [inline]
 __se_sys_clone kernel/fork.c:2327 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2327
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7789:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3499 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3765
 put_pid.part.0+0x111/0x150 kernel/pid.c:111
 put_pid+0x20/0x30 kernel/pid.c:105
 fl_free+0xbe/0xe0 net/ipv6/ip6_flowlabel.c:102
 ip6_fl_gc+0x295/0x3e0 net/ipv6/ip6_flowlabel.c:152
 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:293

The buggy address belongs to the object at ffff888094012a00
 which belongs to the cache pid_2 of size 88
The buggy address is located 4 bytes inside of
 88-byte region [ffff888094012a00, ffff888094012a58)
The buggy address belongs to the page:
page:ffffea0002500480 count:1 mapcount:0 mapping:ffff88809a483080 index:0xffff888094012980
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00018a3508 ffffea0002524a88 ffff88809a483080
raw: ffff888094012980 ffff888094012000 000000010000001b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888094012900: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff888094012980: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
>ffff888094012a00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
                   ^
 ffff888094012a80: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff888094012b00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc

Fixes: 4f82f45730c6 ("net ip6 flowlabel: Make owner a union of struct pid * and kuid_t")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
vrf: Use orig netdev to count Ip6InNoRoutes and a fresh route lookup when sending dest unreach 2019-04-30T03:28:52+00:00 Stephen Suryaputra ssuryaextr@gmail.com 2019-04-27T13:14:33+00:00 1d3fd8a10bedb09006cfc963bfcf051c3021f626 When there is no route to an IPv6 dest addr, skb_dst(skb) points to loopback dev in the case of that the IP6CB(skb)->iif is enslaved to a vrf. This causes Ip6InNoRoutes to be incremented on the loopback dev. This also causes the lookup to fail on icmpv6_send() and the dest unreachable to not sent and Ip6OutNoRoutes gets incremented on the loopback dev. To reproduce: * Gateway configuration: ip link add dev vrf_258 type vrf table 258 ip link set dev enp0s9 master vrf_258 ip addr add 66:1/64 dev enp0s9 ip -6 route add unreachable default metric 8192 table 258 sysctl -w net.ipv6.conf.all.forwarding=1 sysctl -w net.ipv6.conf.enp0s9.forwarding=1 * Sender configuration: ip addr add 66::2/64 dev enp0s9 ip -6 route add default via 66::1 and ping 67::1 for example from the sender. Fix this by counting on the original netdev and reset the skb dst to force a fresh lookup. v2: Fix typo of destination address in the repro steps. v3: Simplify the loopback check (per David Ahern) and use reverse Christmas tree format (per David Miller). Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Tested-by: David Ahern <dsahern@gmail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When there is no route to an IPv6 dest addr, skb_dst(skb) points
to loopback dev in the case of that the IP6CB(skb)->iif is
enslaved to a vrf. This causes Ip6InNoRoutes to be incremented on the
loopback dev. This also causes the lookup to fail on icmpv6_send() and
the dest unreachable to not sent and Ip6OutNoRoutes gets incremented on
the loopback dev.

To reproduce:
* Gateway configuration:
        ip link add dev vrf_258 type vrf table 258
        ip link set dev enp0s9 master vrf_258
        ip addr add 66:1/64 dev enp0s9
        ip -6 route add unreachable default metric 8192 table 258
        sysctl -w net.ipv6.conf.all.forwarding=1
        sysctl -w net.ipv6.conf.enp0s9.forwarding=1
* Sender configuration:
        ip addr add 66::2/64 dev enp0s9
        ip -6 route add default via 66::1
and ping 67::1 for example from the sender.

Fix this by counting on the original netdev and reset the skb dst to
force a fresh lookup.

v2: Fix typo of destination address in the repro steps.
v3: Simplify the loopback check (per David Ahern) and use reverse
    Christmas tree format (per David Miller).

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6: invert flowlabel sharing check in process and user mode 2019-04-29T22:22:56+00:00 Willem de Bruijn willemb@google.com 2019-04-25T16:06:54+00:00 95c169251bf734aa555a1e8043e4d88ec97a04ec A request for a flowlabel fails in process or user exclusive mode must fail if the caller pid or uid does not match. Invert the test. Previously, the test was unsafe wrt PID recycling, but indeed tested for inequality: fl1->owner != fl->owner Fixes: 4f82f45730c68 ("net ip6 flowlabel: Make owner a union of struct pid* and kuid_t") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
A request for a flowlabel fails in process or user exclusive mode must
fail if the caller pid or uid does not match. Invert the test.

Previously, the test was unsafe wrt PID recycling, but indeed tested
for inequality: fl1->owner != fl->owner

Fixes: 4f82f45730c68 ("net ip6 flowlabel: Make owner a union of struct pid* and kuid_t")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: ipv6: addrlabel: fix spelling mistake "requewst" -> "request" 2019-04-18T17:44:17+00:00 Colin Ian King colin.king@canonical.com 2019-04-18T10:39:18+00:00 d5f6db353829fe3867bbf9cd73fd8d631e2346f1 There is a spelling mistake in a NL_SET_ERR_MSG_MOD error message, fix it. Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
There is a spelling mistake in a NL_SET_ERR_MSG_MOD error message,
fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
route: Avoid crash from dereferencing NULL rt->from 2019-04-15T20:31:59+00:00 Jonathan Lemon jonathan.lemon@gmail.com 2019-04-14T21:21:29+00:00 9c69a13205151c0d801de9f9d83a818e6e8f60ec When __ip6_rt_update_pmtu() is called, rt->from is RCU dereferenced, but is never checked for null - rt6_flush_exceptions() may have removed the entry. [ 1913.989004] RIP: 0010:ip6_rt_cache_alloc+0x13/0x170 [ 1914.209410] Call Trace: [ 1914.214798] <IRQ> [ 1914.219226] __ip6_rt_update_pmtu+0xb0/0x190 [ 1914.228649] ip6_tnl_xmit+0x2c2/0x970 [ip6_tunnel] [ 1914.239223] ? ip6_tnl_parse_tlv_enc_lim+0x32/0x1a0 [ip6_tunnel] [ 1914.252489] ? __gre6_xmit+0x148/0x530 [ip6_gre] [ 1914.262678] ip6gre_tunnel_xmit+0x17e/0x3c7 [ip6_gre] [ 1914.273831] dev_hard_start_xmit+0x8d/0x1f0 [ 1914.283061] sch_direct_xmit+0xfa/0x230 [ 1914.291521] __qdisc_run+0x154/0x4b0 [ 1914.299407] net_tx_action+0x10e/0x1f0 [ 1914.307678] __do_softirq+0xca/0x297 [ 1914.315567] irq_exit+0x96/0xa0 [ 1914.322494] smp_apic_timer_interrupt+0x68/0x130 [ 1914.332683] apic_timer_interrupt+0xf/0x20 [ 1914.341721] </IRQ> Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected") Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@gmail.com> Reviewed-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When __ip6_rt_update_pmtu() is called, rt->from is RCU dereferenced, but is
never checked for null - rt6_flush_exceptions() may have removed the entry.

[ 1913.989004] RIP: 0010:ip6_rt_cache_alloc+0x13/0x170
[ 1914.209410] Call Trace:
[ 1914.214798]  <IRQ>
[ 1914.219226]  __ip6_rt_update_pmtu+0xb0/0x190
[ 1914.228649]  ip6_tnl_xmit+0x2c2/0x970 [ip6_tunnel]
[ 1914.239223]  ? ip6_tnl_parse_tlv_enc_lim+0x32/0x1a0 [ip6_tunnel]
[ 1914.252489]  ? __gre6_xmit+0x148/0x530 [ip6_gre]
[ 1914.262678]  ip6gre_tunnel_xmit+0x17e/0x3c7 [ip6_gre]
[ 1914.273831]  dev_hard_start_xmit+0x8d/0x1f0
[ 1914.283061]  sch_direct_xmit+0xfa/0x230
[ 1914.291521]  __qdisc_run+0x154/0x4b0
[ 1914.299407]  net_tx_action+0x10e/0x1f0
[ 1914.307678]  __do_softirq+0xca/0x297
[ 1914.315567]  irq_exit+0x96/0xa0
[ 1914.322494]  smp_apic_timer_interrupt+0x68/0x130
[ 1914.332683]  apic_timer_interrupt+0xf/0x20
[ 1914.341721]  </IRQ>

Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected")
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
udpv6: Check address length before reading address family 2019-04-12T17:25:03+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2019-04-12T10:56:39+00:00 bddc028a4f2ac8cf4d0cd1c696b5f95d8305a553 KMSAN will complain if valid address length passed to udpv6_pre_connect() is shorter than sizeof("struct sockaddr"->sa_family) bytes. (This patch is bogus if it is guaranteed that udpv6_pre_connect() is always called after checking "struct sockaddr"->sa_family. In that case, we want a comment why we don't need to check valid address length here.) Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
KMSAN will complain if valid address length passed to udpv6_pre_connect()
is shorter than sizeof("struct sockaddr"->sa_family) bytes.

(This patch is bogus if it is guaranteed that udpv6_pre_connect() is
always called after checking "struct sockaddr"->sa_family. In that case,
we want a comment why we don't need to check valid address length here.)

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: ip6_gre: fix possible use-after-free in ip6erspan_rcv 2019-04-08T23:16:47+00:00 Lorenzo Bianconi lorenzo.bianconi@redhat.com 2019-04-06T15:16:53+00:00 2a3cabae4536edbcb21d344e7aa8be7a584d2afb erspan_v6 tunnels run __iptunnel_pull_header on received skbs to remove erspan header. This can determine a possible use-after-free accessing pkt_md pointer in ip6erspan_rcv since the packet will be 'uncloned' running pskb_expand_head if it is a cloned gso skb (e.g if the packet has been sent though a veth device). Fix it resetting pkt_md pointer after __iptunnel_pull_header Fixes: 1d7e2ed22f8d ("net: erspan: refactor existing erspan code") Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
erspan_v6 tunnels run __iptunnel_pull_header on received skbs to remove
erspan header. This can determine a possible use-after-free accessing
pkt_md pointer in ip6erspan_rcv since the packet will be 'uncloned'
running pskb_expand_head if it is a cloned gso skb (e.g if the packet has
been sent though a veth device). Fix it resetting pkt_md pointer after
__iptunnel_pull_header

Fixes: 1d7e2ed22f8d ("net: erspan: refactor existing erspan code")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>