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2018-02-26l2tp: fix tunnel lookup use-after-free raceJames Chapman1-7/+7
l2tp_tunnel_get walks the tunnel list to find a matching tunnel instance and if a match is found, its refcount is increased before returning the tunnel pointer. But when tunnel objects are destroyed, they are on the tunnel list after their refcount hits zero. Fix this by moving the code that removes the tunnel from the tunnel list from the tunnel socket destructor into in the l2tp_tunnel_delete path, before the tunnel refcount is decremented. refcount_t: increment on 0; use-after-free. WARNING: CPU: 3 PID: 13507 at lib/refcount.c:153 refcount_inc+0x47/0x50 Modules linked in: CPU: 3 PID: 13507 Comm: syzbot_6e6a5ec8 Not tainted 4.16.0-rc2+ #36 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 RIP: 0010:refcount_inc+0x47/0x50 RSP: 0018:ffff8800136ffb20 EFLAGS: 00010286 RAX: dffffc0000000008 RBX: ffff880017068e68 RCX: ffffffff814d3333 RDX: 0000000000000000 RSI: ffff88001a59f6d8 RDI: ffff88001a59f6d8 RBP: ffff8800136ffb28 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8800136ffab0 R11: 0000000000000000 R12: ffff880017068e50 R13: 0000000000000000 R14: ffff8800174da800 R15: 0000000000000004 FS: 00007f403ab1e700(0000) GS:ffff88001a580000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000205fafd2 CR3: 0000000016770000 CR4: 00000000000006e0 Call Trace: l2tp_tunnel_get+0x2dd/0x4e0 pppol2tp_connect+0x428/0x13c0 ? pppol2tp_session_create+0x170/0x170 ? __might_fault+0x115/0x1d0 ? lock_downgrade+0x860/0x860 ? __might_fault+0xe5/0x1d0 ? security_socket_connect+0x8e/0xc0 SYSC_connect+0x1b6/0x310 ? SYSC_bind+0x280/0x280 ? __do_page_fault+0x5d1/0xca0 ? up_read+0x1f/0x40 ? __do_page_fault+0x3c8/0xca0 SyS_connect+0x29/0x30 ? SyS_accept+0x40/0x40 do_syscall_64+0x1e0/0x730 ? trace_hardirqs_off_thunk+0x1a/0x1c entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f403a42f259 RSP: 002b:00007f403ab1dee8 EFLAGS: 00000296 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00000000205fafe4 RCX: 00007f403a42f259 RDX: 000000000000002e RSI: 00000000205fafd2 RDI: 0000000000000004 RBP: 00007f403ab1df20 R08: 00007f403ab1e700 R09: 0000000000000000 R10: 00007f403ab1e700 R11: 0000000000000296 R12: 0000000000000000 R13: 00007ffc81906cbf R14: 0000000000000000 R15: 00007f403ab2b040 Code: 3b ff 5b 5d c3 e8 ca 5f 3b ff 80 3d 49 8e 66 04 00 75 ea e8 bc 5f 3b ff 48 c7 c7 60 69 64 85 c6 05 34 8e 66 04 01 e8 59 49 15 ff <0f> 0b eb ce 0f 1f 44 00 00 55 48 89 e5 41 56 41 55 41 54 53 49 Fixes: f8ccac0e44934 ("l2tp: put tunnel socket release on a workqueue") Reported-and-tested-by: syzbot+19c09769f14b48810113@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+347bd5acde002e353a36@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+6e6a5ec8de31a94cd015@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+9df43faf09bd400f2993@syzkaller.appspotmail.com Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26l2tp: fix race in pppol2tp_release with session object destroyJames Chapman1-25/+27
pppol2tp_release uses call_rcu to put the final ref on its socket. But the session object doesn't hold a ref on the session socket so may be freed while the pppol2tp_put_sk RCU callback is scheduled. Fix this by having the session hold a ref on its socket until the session is destroyed. It is this ref that is dropped via call_rcu. Sessions are also deleted via l2tp_tunnel_closeall. This must now also put the final ref via call_rcu. So move the call_rcu call site into pppol2tp_session_close so that this happens in both destroy paths. A common destroy path should really be implemented, perhaps with l2tp_tunnel_closeall calling l2tp_session_delete like pppol2tp_release does, but this will be looked at later. ODEBUG: activate active (active state 1) object type: rcu_head hint: (null) WARNING: CPU: 3 PID: 13407 at lib/debugobjects.c:291 debug_print_object+0x166/0x220 Modules linked in: CPU: 3 PID: 13407 Comm: syzbot_19c09769 Not tainted 4.16.0-rc2+ #38 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 RIP: 0010:debug_print_object+0x166/0x220 RSP: 0018:ffff880013647a00 EFLAGS: 00010082 RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff814d3333 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88001a59f6d0 RBP: ffff880013647a40 R08: 0000000000000000 R09: 0000000000000001 R10: ffff8800136479a8 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff86161420 R14: ffffffff85648b60 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88001a580000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020e77000 CR3: 0000000006022000 CR4: 00000000000006e0 Call Trace: debug_object_activate+0x38b/0x530 ? debug_object_assert_init+0x3b0/0x3b0 ? __mutex_unlock_slowpath+0x85/0x8b0 ? pppol2tp_session_destruct+0x110/0x110 __call_rcu.constprop.66+0x39/0x890 ? __call_rcu.constprop.66+0x39/0x890 call_rcu_sched+0x17/0x20 pppol2tp_release+0x2c7/0x440 ? fcntl_setlk+0xca0/0xca0 ? sock_alloc_file+0x340/0x340 sock_release+0x92/0x1e0 sock_close+0x1b/0x20 __fput+0x296/0x6e0 ____fput+0x1a/0x20 task_work_run+0x127/0x1a0 do_exit+0x7f9/0x2ce0 ? SYSC_connect+0x212/0x310 ? mm_update_next_owner+0x690/0x690 ? up_read+0x1f/0x40 ? __do_page_fault+0x3c8/0xca0 do_group_exit+0x10d/0x330 ? do_group_exit+0x330/0x330 SyS_exit_group+0x22/0x30 do_syscall_64+0x1e0/0x730 ? trace_hardirqs_off_thunk+0x1a/0x1c entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f362e471259 RSP: 002b:00007ffe389abe08 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f362e471259 RDX: 00007f362e471259 RSI: 000000000000002e RDI: 0000000000000000 RBP: 00007ffe389abe30 R08: 0000000000000000 R09: 00007f362e944270 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400b60 R13: 00007ffe389abf50 R14: 0000000000000000 R15: 0000000000000000 Code: 8d 3c dd a0 8f 64 85 48 89 fa 48 c1 ea 03 80 3c 02 00 75 7b 48 8b 14 dd a0 8f 64 85 4c 89 f6 48 c7 c7 20 85 64 85 e 8 2a 55 14 ff <0f> 0b 83 05 ad 2a 68 04 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 Fixes: ee40fb2e1eb5b ("l2tp: protect sock pointer of struct pppol2tp_session with RCU") Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26l2tp: fix races with tunnel socket closeJames Chapman4-116/+42
The tunnel socket tunnel->sock (struct sock) is accessed when preparing a new ppp session on a tunnel at pppol2tp_session_init. If the socket is closed by a thread while another is creating a new session, the threads race. In pppol2tp_connect, the tunnel object may be created if the pppol2tp socket is associated with the special session_id 0 and the tunnel socket is looked up using the provided fd. When handling this, pppol2tp_connect cannot sock_hold the tunnel socket to prevent it being destroyed during pppol2tp_connect since this may itself may race with the socket being destroyed. Doing sockfd_lookup in pppol2tp_connect isn't sufficient to prevent tunnel->sock going away either because a given tunnel socket fd may be reused between calls to pppol2tp_connect. Instead, have l2tp_tunnel_create sock_hold the tunnel socket before it does sockfd_put. This ensures that the tunnel's socket is always extant while the tunnel object exists. Hold a ref on the socket until the tunnel is destroyed and ensure that all tunnel destroy paths go through a common function (l2tp_tunnel_delete) since this will do the final sock_put to release the tunnel socket. Since the tunnel's socket is now guaranteed to exist if the tunnel exists, we no longer need to use sockfd_lookup via l2tp_sock_to_tunnel to derive the tunnel from the socket since this is always sk_user_data. Also, sessions no longer sock_hold the tunnel socket since sessions already hold a tunnel ref and the tunnel sock will not be freed until the tunnel is freed. Removing these sock_holds in l2tp_session_register avoids a possible sock leak in the pppol2tp_connect error path if l2tp_session_register succeeds but attaching a ppp channel fails. The pppol2tp_connect error path could have been fixed instead and have the sock ref dropped when the session is freed, but doing a sock_put of the tunnel socket when the session is freed would require a new session_free callback. It is simpler to just remove the sock_hold of the tunnel socket in l2tp_session_register, now that the tunnel socket lifetime is guaranteed. Finally, some init code in l2tp_tunnel_create is reordered to ensure that the new tunnel object's refcount is set and the tunnel socket ref is taken before the tunnel socket destructor callbacks are set. kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN Modules linked in: CPU: 0 PID: 4360 Comm: syzbot_19c09769 Not tainted 4.16.0-rc2+ #34 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 RIP: 0010:pppol2tp_session_init+0x1d6/0x500 RSP: 0018:ffff88001377fb40 EFLAGS: 00010212 RAX: dffffc0000000000 RBX: ffff88001636a940 RCX: ffffffff84836c1d RDX: 0000000000000045 RSI: 0000000055976744 RDI: 0000000000000228 RBP: ffff88001377fb60 R08: ffffffff84836bc8 R09: 0000000000000002 R10: ffff88001377fab8 R11: 0000000000000001 R12: 0000000000000000 R13: ffff88001636aac8 R14: ffff8800160f81c0 R15: 1ffff100026eff76 FS: 00007ffb3ea66700(0000) GS:ffff88001a400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020e77000 CR3: 0000000016261000 CR4: 00000000000006f0 Call Trace: pppol2tp_connect+0xd18/0x13c0 ? pppol2tp_session_create+0x170/0x170 ? __might_fault+0x115/0x1d0 ? lock_downgrade+0x860/0x860 ? __might_fault+0xe5/0x1d0 ? security_socket_connect+0x8e/0xc0 SYSC_connect+0x1b6/0x310 ? SYSC_bind+0x280/0x280 ? __do_page_fault+0x5d1/0xca0 ? up_read+0x1f/0x40 ? __do_page_fault+0x3c8/0xca0 SyS_connect+0x29/0x30 ? SyS_accept+0x40/0x40 do_syscall_64+0x1e0/0x730 ? trace_hardirqs_off_thunk+0x1a/0x1c entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7ffb3e376259 RSP: 002b:00007ffeda4f6508 EFLAGS: 00000202 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000020e77012 RCX: 00007ffb3e376259 RDX: 000000000000002e RSI: 0000000020e77000 RDI: 0000000000000004 RBP: 00007ffeda4f6540 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400b60 R13: 00007ffeda4f6660 R14: 0000000000000000 R15: 0000000000000000 Code: 80 3d b0 ff 06 02 00 0f 84 07 02 00 00 e8 13 d6 db fc 49 8d bc 24 28 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f a 48 c1 ea 03 <80> 3c 02 00 0f 85 ed 02 00 00 4d 8b a4 24 28 02 00 00 e8 13 16 Fixes: 80d84ef3ff1dd ("l2tp: prevent l2tp_tunnel_delete racing with userspace close") Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26l2tp: don't use inet_shutdown on ppp session destroyJames Chapman1-10/+0
Previously, if a ppp session was closed, we called inet_shutdown to mark the socket as unconnected such that userspace would get errors and then close the socket. This could race with userspace closing the socket. Instead, leave userspace to close the socket in its own time (our session will be detached anyway). BUG: KASAN: use-after-free in inet_shutdown+0x5d/0x1c0 Read of size 4 at addr ffff880010ea3ac0 by task syzbot_347bd5ac/8296 CPU: 3 PID: 8296 Comm: syzbot_347bd5ac Not tainted 4.16.0-rc1+ #91 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 Call Trace: dump_stack+0x101/0x157 ? inet_shutdown+0x5d/0x1c0 print_address_description+0x78/0x260 ? inet_shutdown+0x5d/0x1c0 kasan_report+0x240/0x360 __asan_load4+0x78/0x80 inet_shutdown+0x5d/0x1c0 ? pppol2tp_show+0x80/0x80 pppol2tp_session_close+0x68/0xb0 l2tp_tunnel_closeall+0x199/0x210 ? udp_v6_flush_pending_frames+0x90/0x90 l2tp_udp_encap_destroy+0x6b/0xc0 ? l2tp_tunnel_del_work+0x2e0/0x2e0 udpv6_destroy_sock+0x8c/0x90 sk_common_release+0x47/0x190 udp_lib_close+0x15/0x20 inet_release+0x85/0xd0 inet6_release+0x43/0x60 sock_release+0x53/0x100 ? sock_alloc_file+0x260/0x260 sock_close+0x1b/0x20 __fput+0x19f/0x380 ____fput+0x1a/0x20 task_work_run+0xd2/0x110 exit_to_usermode_loop+0x18d/0x190 do_syscall_64+0x389/0x3b0 entry_SYSCALL_64_after_hwframe+0x26/0x9b RIP: 0033:0x7fe240a45259 RSP: 002b:00007fe241132df8 EFLAGS: 00000297 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe240a45259 RDX: 00007fe240a45259 RSI: 0000000000000000 RDI: 00000000000000a5 RBP: 00007fe241132e20 R08: 00007fe241133700 R09: 0000000000000000 R10: 00007fe241133700 R11: 0000000000000297 R12: 0000000000000000 R13: 00007ffc49aff84f R14: 0000000000000000 R15: 00007fe241141040 Allocated by task 8331: save_stack+0x43/0xd0 kasan_kmalloc+0xad/0xe0 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0x144/0x3e0 sock_alloc_inode+0x22/0x130 alloc_inode+0x3d/0xf0 new_inode_pseudo+0x1c/0x90 sock_alloc+0x30/0x110 __sock_create+0xaa/0x4c0 SyS_socket+0xbe/0x130 do_syscall_64+0x128/0x3b0 entry_SYSCALL_64_after_hwframe+0x26/0x9b Freed by task 8314: save_stack+0x43/0xd0 __kasan_slab_free+0x11a/0x170 kasan_slab_free+0xe/0x10 kmem_cache_free+0x88/0x2b0 sock_destroy_inode+0x49/0x50 destroy_inode+0x77/0xb0 evict+0x285/0x340 iput+0x429/0x530 dentry_unlink_inode+0x28c/0x2c0 __dentry_kill+0x1e3/0x2f0 dput.part.21+0x500/0x560 dput+0x24/0x30 __fput+0x2aa/0x380 ____fput+0x1a/0x20 task_work_run+0xd2/0x110 exit_to_usermode_loop+0x18d/0x190 do_syscall_64+0x389/0x3b0 entry_SYSCALL_64_after_hwframe+0x26/0x9b Fixes: fd558d186df2c ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26l2tp: don't use inet_shutdown on tunnel destroyJames Chapman1-9/+2
Previously, if a tunnel was closed, we called inet_shutdown to mark the socket as unconnected such that userspace would get errors and then close the socket. This could race with userspace closing the socket. Instead, leave userspace to close the socket in its own time (our tunnel will be detached anyway). BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0 IP: __lock_acquire+0x263/0x1630 PGD 0 P4D 0 Oops: 0000 [#1] SMP KASAN Modules linked in: CPU: 2 PID: 42 Comm: kworker/u8:2 Not tainted 4.15.0-rc7+ #129 Workqueue: l2tp l2tp_tunnel_del_work RIP: 0010:__lock_acquire+0x263/0x1630 RSP: 0018:ffff88001a37fc70 EFLAGS: 00010002 RAX: 0000000000000001 RBX: 0000000000000088 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88001a37fd18 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 00000000000076fd R12: 00000000000000a0 R13: ffff88001a3722c0 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88001ad00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000a0 CR3: 000000001730b000 CR4: 00000000000006e0 Call Trace: ? __lock_acquire+0xc77/0x1630 ? console_trylock+0x11/0xa0 lock_acquire+0x117/0x230 ? lock_sock_nested+0x3a/0xa0 _raw_spin_lock_bh+0x3a/0x50 ? lock_sock_nested+0x3a/0xa0 lock_sock_nested+0x3a/0xa0 inet_shutdown+0x33/0xf0 l2tp_tunnel_del_work+0x60/0xef process_one_work+0x1ea/0x5f0 ? process_one_work+0x162/0x5f0 worker_thread+0x48/0x3e0 ? trace_hardirqs_on+0xd/0x10 kthread+0x108/0x140 ? process_one_work+0x5f0/0x5f0 ? kthread_stop+0x2a0/0x2a0 ret_from_fork+0x24/0x30 Code: 00 41 81 ff ff 1f 00 00 0f 87 7a 13 00 00 45 85 f6 49 8b 85 68 08 00 00 0f 84 ae 03 00 00 c7 44 24 18 00 00 00 00 e9 f0 00 00 00 <49> 81 3c 24 80 93 3f 83 b8 00 00 00 00 44 0f 44 c0 83 fe 01 0f RIP: __lock_acquire+0x263/0x1630 RSP: ffff88001a37fc70 CR2: 00000000000000a0 Fixes: 309795f4bec2d ("l2tp: Add netlink control API for L2TP") Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19l2tp: remove switch block in l2tp_nl_cmd_session_create()Lorenzo Bianconi1-21/+0
Remove the switch block in l2tp_nl_cmd_session_create() that checks pseudowire-specific parameters since just L2TP_PWTYPE_ETH and L2TP_PWTYPE_PPP are currently supported and no actual checks are performed. Moreover the L2TP_PWTYPE_IP/default case presents a harmless issue in error handling (break instead of goto out_tunnel) Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Acked-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19l2tp: remove l2specific_len configurable parameterLorenzo Bianconi4-8/+1
Remove l2specific_len configuration parameter since now L2-Specific Sublayer length is computed according to l2specific_type provided by userspace. Reviewed-by: Guillaume Nault <g.nault@alphalink.fr> Tested-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19l2tp: remove l2specific_len dependency in l2tp_coreLorenzo Bianconi2-18/+27
Remove l2specific_len dependency while building l2tpv3 header or parsing the received frame since default L2-Specific Sublayer is always four bytes long and we don't need to rely on a user supplied value. Moreover in l2tp netlink code there are no sanity checks to enforce the relation between l2specific_len and l2specific_type, so sending a malformed netlink message is possible to set l2specific_type to L2TP_L2SPECTYPE_DEFAULT (or even L2TP_L2SPECTYPE_NONE) and set l2specific_len to a value greater than 4 leaking memory on the wire and sending corrupted frames. Reviewed-by: Guillaume Nault <g.nault@alphalink.fr> Tested-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19l2tp: double-check l2specific_type provided by userspaceLorenzo Bianconi1-2/+9
Add sanity check on l2specific_type provided by userspace in l2tp_nl_cmd_session_create() since just L2TP_L2SPECTYPE_DEFAULT and L2TP_L2SPECTYPE_NONE are currently supported. Moreover explicitly set l2specific_type to L2TP_L2SPECTYPE_DEFAULT only if the userspace does not provide a value for it Reviewed-by: Guillaume Nault <g.nault@alphalink.fr> Tested-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-16net: delete /proc THIS_MODULE referencesAlexey Dobriyan1-1/+0
/proc has been ignoring struct file_operations::owner field for 10 years. Specifically, it started with commit 786d7e1612f0b0adb6046f19b906609e4fe8b1ba ("Fix rmmod/read/write races in /proc entries"). Notice the chunk where inode->i_fop is initialized with proxy struct file_operations for regular files: - if (de->proc_fops) - inode->i_fop = de->proc_fops; + if (de->proc_fops) { + if (S_ISREG(inode->i_mode)) + inode->i_fop = &proc_reg_file_ops; + else + inode->i_fop = de->proc_fops; + } VFS stopped pinning module at this point. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-08l2tp: adjust comments about L2TPv3 offsetsGuillaume Nault1-4/+3
The "offset" option has been removed by commit 900631ee6a26 ("l2tp: remove configurable payload offset"). Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Acked-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05l2tp: remove configurable payload offsetJames Chapman4-18/+6
If L2TP_ATTR_OFFSET is set to a non-zero value in L2TPv3 tunnels, it results in L2TPv3 packets being transmitted which might not be compliant with the L2TPv3 RFC. This patch has l2tp ignore the offset setting and send all packets with no offset. In more detail: L2TPv2 supports a variable offset from the L2TPv2 header to the payload. The offset value is indicated by an optional field in the L2TP header. Our L2TP implementation already detects the presence of the optional offset and skips that many bytes when handling data received packets. All transmitted packets are always transmitted with no offset. L2TPv3 has no optional offset field in the L2TPv3 packet header. Instead, L2TPv3 defines optional fields in a "Layer-2 Specific Sublayer". At the time when the original L2TP code was written, there was talk at IETF of offset being implemented in a new Layer-2 Specific Sublayer. A L2TP_ATTR_OFFSET netlink attribute was added so that this offset could be configured and the intention was to allow it to be also used to set the tx offset for L2TPv2. However, no L2TPv3 offset was ever specified and the L2TP_ATTR_OFFSET parameter was forgotten about. Setting L2TP_ATTR_OFFSET results in L2TPv3 packets being transmitted with the specified number of bytes padding between L2TPv3 header and payload. This is not compliant with L2TPv3 RFC3931. This change removes the configurable offset altogether while retaining L2TP_ATTR_OFFSET for backwards compatibility. Any L2TP_ATTR_OFFSET value is ignored. Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05l2tp: revert "l2tp: fix missing print session offset info"James Chapman1-2/+0
Revert commit 820da5357572 ("l2tp: fix missing print session offset info"). The peer_offset parameter is removed. Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-05l2tp: revert "l2tp: add peer_offset parameter"James Chapman4-37/+8
Revert commit f15bc54eeecd ("l2tp: add peer_offset parameter"). This is removed because it is adding another configurable offset and configurable offsets are being removed. Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-27l2tp: add peer_offset parameterLorenzo Bianconi4-8/+37
Introduce peer_offset parameter in order to add the capability to specify two different values for payload offset on tx/rx side. If just offset is provided by userspace use it for rx side as well in order to maintain compatibility with older l2tp versions Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-27l2tp: fix missing print session offset infoHangbin Liu1-0/+2
Report offset parameter in L2TP_CMD_SESSION_GET command if it has been configured by userspace Fixes: 309795f4bec ("l2tp: Add netlink control API for L2TP") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-14l2tp: exit_net cleanup check addedVasily Averin1-0/+4
Be sure that l2tp_session_hlist array initialized in net_init hook was return to initial state. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11l2tp: remove the .tunnel_sock field from struct pppol2tp_sessionGuillaume Nault1-10/+0
The last user of .tunnel_sock is pppol2tp_connect() which defensively uses it to verify internal data consistency. This check isn't necessary: l2tp_session_get() guarantees that the returned session belongs to the tunnel passed as parameter. And .tunnel_sock is never updated, so checking that it still points to the parent tunnel socket is useless; that test can never fail. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11l2tp: avoid using ->tunnel_sock for getting session's parent tunnelGuillaume Nault1-54/+12
Sessions don't need to use l2tp_sock_to_tunnel(xxx->tunnel_sock) for accessing their parent tunnel. They have the .tunnel field in the l2tp_session structure for that. Furthermore, in all these cases, the session is registered, so we're guaranteed that .tunnel isn't NULL and that the session properly holds a reference on the tunnel. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11l2tp: remove .tunnel_sock from struct l2tp_ethGuillaume Nault1-2/+0
This field has never been used. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11l2tp: don't close sessions in l2tp_tunnel_destruct()Guillaume Nault1-2/+0
Sessions are already removed by the proto ->destroy() handlers, and since commit f3c66d4e144a ("l2tp: prevent creation of sessions on terminated tunnels"), we're guaranteed that no new session can be created afterwards. Furthermore, l2tp_tunnel_closeall() can sleep when there are sessions left to close. So we really shouldn't call it in a ->sk_destruct() handler, as it can be used from atomic context. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2-30/+18
Simple cases of overlapping changes in the packet scheduler. Must easier to resolve this time. Which probably means that I screwed it up somehow. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-05l2tp: don't use l2tp_tunnel_find() in l2tp_ip and l2tp_ip6Guillaume Nault2-30/+18
Using l2tp_tunnel_find() in l2tp_ip_recv() is wrong for two reasons: * It doesn't take a reference on the returned tunnel, which makes the call racy wrt. concurrent tunnel deletion. * The lookup is only based on the tunnel identifier, so it can return a tunnel that doesn't match the packet's addresses or protocol. For example, a packet sent to an L2TPv3 over IPv6 tunnel can be delivered to an L2TPv2 over UDPv4 tunnel. This is worse than a simple cross-talk: when delivering the packet to an L2TP over UDP tunnel, the corresponding socket is UDP, where ->sk_backlog_rcv() is NULL. Calling sk_receive_skb() will then crash the kernel by trying to execute this callback. And l2tp_tunnel_find() isn't even needed here. __l2tp_ip_bind_lookup() properly checks the socket binding and connection settings. It was used as a fallback mechanism for finding tunnels that didn't have their data path registered yet. But it's not limited to this case and can be used to replace l2tp_tunnel_find() in the general case. Fix l2tp_ip6 in the same way. Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support") Fixes: a32e0eec7042 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+1
Files removed in 'net-next' had their license header updated in 'net'. We take the remove from 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-02Merge tag 'spdx_identifiers-4.14-rc8' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull initial SPDX identifiers from Greg KH: "License cleanup: add SPDX license identifiers to some files Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" * tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: License cleanup: add SPDX license identifier to uapi header files with a license License cleanup: add SPDX license identifier to uapi header files with no license License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-1/+6
Smooth Cong Wang's bug fix into 'net-next'. Basically put the bulk of the tcf_block_put() logic from 'net' into tcf_block_put_ext(), but after the offload unbind. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01l2tp: remove field 'dev' from struct l2tp_ethGuillaume Nault1-5/+0
This field has never been used. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01l2tp: remove l2tp_tunnel_count and l2tp_session_countGuillaume Nault1-10/+0
These variables have never been used. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01l2tp: remove l2tp specific refcount debuggingGuillaume Nault1-22/+2
With conversion to refcount_t, such manual debugging code doesn't make sense anymore. The tunnel part was already dropped by 54652eb12c1b ("l2tp: hold tunnel while looking up sessions in l2tp_netlink"). Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01l2tp: remove ->ref() and ->deref()Guillaume Nault7-79/+25
The ->ref() and ->deref() callbacks are unused since PPP stopped using them in ee40fb2e1eb5 ("l2tp: protect sock pointer of struct pppol2tp_session with RCU"). We can thus remove them from struct l2tp_session and drop the do_ref parameter of l2tp_session_get*(). Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-31l2tp: hold tunnel in pppol2tp_connect()Guillaume Nault1-1/+6
Use l2tp_tunnel_get() in pppol2tp_connect() to ensure the tunnel isn't going to disappear while processing the rest of the function. Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29l2tp: initialise PPP sessions before registering themGuillaume Nault1-31/+38
pppol2tp_connect() initialises L2TP sessions after they've been exposed to the rest of the system by l2tp_session_register(). This puts sessions into transient states that are the source of several races, in particular with session's deletion path. This patch centralises the initialisation code into pppol2tp_session_init(), which is called before the registration phase. The only field that can't be set before session registration is the pppol2tp socket pointer, which has already been converted to RCU. So pppol2tp_connect() should now be race-free. The session's .session_close() callback is now set before registration. Therefore, it's always called when l2tp_core deletes the session, even if it was created by pppol2tp_session_create() and hasn't been plugged to a pppol2tp socket yet. That'd prevent session free because the extra reference taken by pppol2tp_session_close() wouldn't be dropped by the socket's ->sk_destruct() callback (pppol2tp_session_destruct()). We could set .session_close() only while connecting a session to its pppol2tp socket, or teach pppol2tp_session_close() to avoid grabbing a reference when the session isn't connected, but that'd require adding some form of synchronisation to be race free. Instead of that, we can just let the pppol2tp socket hold a reference on the session as soon as it starts depending on it (that is, in pppol2tp_connect()). Then we don't need to utilise pppol2tp_session_close() to hold a reference at the last moment to prevent l2tp_core from dropping it. When releasing the socket, pppol2tp_release() now deletes the session using the standard l2tp_session_delete() function, instead of merely removing it from hash tables. l2tp_session_delete() drops the reference the sessions holds on itself, but also makes sure it doesn't remove a session twice. So it can safely be called, even if l2tp_core already tried, or is concurrently trying, to remove the session. Finally, pppol2tp_session_destruct() drops the reference held by the socket. Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29l2tp: protect sock pointer of struct pppol2tp_session with RCUGuillaume Nault1-53/+101
pppol2tp_session_create() registers sessions that can't have their corresponding socket initialised. This socket has to be created by userspace, then connected to the session by pppol2tp_connect(). Therefore, we need to protect the pppol2tp socket pointer of L2TP sessions, so that it can safely be updated when userspace is connecting or closing the socket. This will eventually allow pppol2tp_connect() to avoid generating transient states while initialising its parts of the session. To this end, this patch protects the pppol2tp socket pointer using RCU. The pppol2tp socket pointer is still set in pppol2tp_connect(), but only once we know the function isn't going to fail. It's eventually reset by pppol2tp_release(), which now has to wait for a grace period to elapse before it can drop the last reference on the socket. This ensures that pppol2tp_session_get_sock() can safely grab a reference on the socket, even after ps->sk is reset to NULL but before this operation actually gets visible from pppol2tp_session_get_sock(). The rest is standard RCU conversion: pppol2tp_recv(), which already runs in atomic context, is simply enclosed by rcu_read_lock() and rcu_read_unlock(), while other functions are converted to use pppol2tp_session_get_sock() followed by sock_put(). pppol2tp_session_setsockopt() is a special case. It used to retrieve the pppol2tp socket from the L2TP session, which itself was retrieved from the pppol2tp socket. Therefore we can just avoid dereferencing ps->sk and directly use the original socket pointer instead. With all users of ps->sk now handling NULL and concurrent updates, the L2TP ->ref() and ->deref() callbacks aren't needed anymore. Therefore, rather than converting pppol2tp_session_sock_hold() and pppol2tp_session_sock_put(), we can just drop them. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29l2tp: initialise l2tp_eth sessions before registering themGuillaume Nault1-31/+75
Sessions must be initialised before being made externally visible by l2tp_session_register(). Otherwise the session may be concurrently deleted before being initialised, which can confuse the deletion path and eventually lead to kernel oops. Therefore, we need to move l2tp_session_register() down in l2tp_eth_create(), but also handle the intermediate step where only the session or the netdevice has been registered. We can't just call l2tp_session_register() in ->ndo_init() because we'd have no way to properly undo this operation in ->ndo_uninit(). Instead, let's register the session and the netdevice in two different steps and protect the session's device pointer with RCU. And now that we allow the session's .dev field to be NULL, we don't need to prevent the netdevice from being removed anymore. So we can drop the dev_hold() and dev_put() calls in l2tp_eth_create() and l2tp_eth_dev_uninit(). Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29l2tp: don't register sessions in l2tp_session_create()Guillaume Nault4-20/+36
Sessions created by l2tp_session_create() aren't fully initialised: some pseudo-wire specific operations need to be done before making the session usable. Therefore the PPP and Ethernet pseudo-wires continue working on the returned l2tp session while it's already been exposed to the rest of the system. This can lead to various issues. In particular, the session may enter the deletion process before having been fully initialised, which will confuse the session removal code. This patch moves session registration out of l2tp_session_create(), so that callers can control when the session is exposed to the rest of the system. This is done by the new l2tp_session_register() function. Only pppol2tp_session_create() can be easily converted to avoid modifying its session after registration (the debug message is dropped in order to avoid the need for holding a reference on the session). For pppol2tp_connect() and l2tp_eth_create()), more work is needed. That'll be done in followup patches. For now, let's just register the session right after its creation, like it was done before. The only difference is that we can easily take a reference on the session before registering it, so, at least, we're sure it's not going to be freed while we're working on it. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27l2tp: cleanup l2tp_tunnel_delete callsJiri Slaby2-2/+2
l2tp_tunnel_delete does not return anything since commit 62b982eeb458 ("l2tp: fix race condition in l2tp_tunnel_delete"). But call sites of l2tp_tunnel_delete still do casts to void to avoid unused return value warnings. Kill these now useless casts. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Sabrina Dubroca <sd@queasysnail.net> Cc: Guillaume Nault <g.nault@alphalink.fr> Cc: David S. Miller <davem@davemloft.net> Cc: netdev@vger.kernel.org Acked-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+3
There were quite a few overlapping sets of changes here. Daniel's bug fix for off-by-ones in the new BPF branch instructions, along with the added allowances for "data_end > ptr + x" forms collided with the metadata additions. Along with those three changes came veritifer test cases, which in their final form I tried to group together properly. If I had just trimmed GIT's conflict tags as-is, this would have split up the meta tests unnecessarily. In the socketmap code, a set of preemption disabling changes overlapped with the rename of bpf_compute_data_end() to bpf_compute_data_pointers(). Changes were made to the mv88e6060.c driver set addr method which got removed in net-next. The hyperv transport socket layer had a locking change in 'net' which overlapped with a change of socket state macro usage in 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-19net: l2tp: mark expected switch fall-throughGustavo A. R. Silva1-1/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Notice that in this particular case I replaced the "NOBREAK" comment with a "fall through" comment, which is what GCC is expecting to find. Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Acked-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-14l2tp: check ps->sock before running pppol2tp_session_ioctl()Guillaume Nault1-0/+3
When pppol2tp_session_ioctl() is called by pppol2tp_tunnel_ioctl(), the session may be unconnected. That is, it was created by pppol2tp_session_create() and hasn't been connected with pppol2tp_connect(). In this case, ps->sock is NULL, so we need to check for this case in order to avoid dereferencing a NULL pointer. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-01l2tp: fix l2tp_eth module loadingGuillaume Nault1-49/+2
The l2tp_eth module crashes if its netlink callbacks are run when the pernet data aren't initialised. We should normally register_pernet_device() before the genl callbacks. However, the pernet data only maintain a list of l2tpeth interfaces, and this list is never used. So let's just drop pernet handling instead. Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-26l2tp: fix race condition in l2tp_tunnel_deleteSabrina Dubroca2-7/+8
If we try to delete the same tunnel twice, the first delete operation does a lookup (l2tp_tunnel_get), finds the tunnel, calls l2tp_tunnel_delete, which queues it for deletion by l2tp_tunnel_del_work. The second delete operation also finds the tunnel and calls l2tp_tunnel_delete. If the workqueue has already fired and started running l2tp_tunnel_del_work, then l2tp_tunnel_delete will queue the same tunnel a second time, and try to free the socket again. Add a dead flag to prevent firing the workqueue twice. Then we can remove the check of queue_work's result that was meant to prevent that race but doesn't. Reproducer: ip l2tp add tunnel tunnel_id 3000 peer_tunnel_id 4000 local 192.168.0.2 remote 192.168.0.1 encap udp udp_sport 5000 udp_dport 6000 ip l2tp add session name l2tp1 tunnel_id 3000 session_id 1000 peer_session_id 2000 ip link set l2tp1 up ip l2tp del tunnel tunnel_id 3000 ip l2tp del tunnel tunnel_id 3000 Fixes: f8ccac0e4493 ("l2tp: put tunnel socket release on a workqueue") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Acked-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-25l2tp: fix race between l2tp_session_delete() and l2tp_tunnel_closeall()Guillaume Nault2-0/+7
There are several ways to remove L2TP sessions: * deleting a session explicitly using the netlink interface (with L2TP_CMD_SESSION_DELETE), * deleting the session's parent tunnel (either by closing the tunnel's file descriptor or using the netlink interface), * closing the PPPOL2TP file descriptor of a PPP pseudo-wire. In some cases, when these methods are used concurrently on the same session, the session can be removed twice, leading to use-after-free bugs. This patch adds a 'dead' flag, used by l2tp_session_delete() and l2tp_tunnel_closeall() to prevent them from stepping on each other's toes. The session deletion path used when closing a PPPOL2TP file descriptor doesn't need to be adapted. It already has to ensure that a session remains valid for the lifetime of its PPPOL2TP file descriptor. So it takes an extra reference on the session in the ->session_close() callback (pppol2tp_session_close()), which is eventually dropped in the ->sk_destruct() callback of the PPPOL2TP socket (pppol2tp_session_destruct()). Still, __l2tp_session_unhash() and l2tp_session_queue_purge() can be called twice and even concurrently for a given session, but thanks to proper locking and re-initialisation of list fields, this is not an issue. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-25l2tp: ensure sessions are freed after their PPPOL2TP socketGuillaume Nault1-4/+4
If l2tp_tunnel_delete() or l2tp_tunnel_closeall() deletes a session right after pppol2tp_release() orphaned its socket, then the 'sock' variable of the pppol2tp_session_close() callback is NULL. Yet the session is still used by pppol2tp_release(). Therefore we need to take an extra reference in any case, to prevent l2tp_tunnel_delete() or l2tp_tunnel_closeall() from freeing the session. Since the pppol2tp_session_close() callback is only set if the session is associated to a PPPOL2TP socket and that both l2tp_tunnel_delete() and l2tp_tunnel_closeall() hold the PPPOL2TP socket before calling pppol2tp_session_close(), we're sure that pppol2tp_session_close() and pppol2tp_session_destruct() are paired and called in the right order. So the reference taken by the former will be released by the later. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-03l2tp: pass tunnel pointer to ->session_create()Guillaume Nault4-25/+17
Using l2tp_tunnel_find() in pppol2tp_session_create() and l2tp_eth_create() is racy, because no reference is held on the returned session. These functions are only used to implement the ->session_create callback which is run by l2tp_nl_cmd_session_create(). Therefore searching for the parent tunnel isn't necessary because l2tp_nl_cmd_session_create() already has a pointer to it and holds a reference. This patch modifies ->session_create()'s prototype to directly pass the the parent tunnel as parameter, thus avoiding searching for it in pppol2tp_session_create() and l2tp_eth_create(). Since we have to touch the ->session_create() call in l2tp_nl_cmd_session_create(), let's also remove the useless conditional: we know that ->session_create isn't NULL at this point because it's already been checked earlier in this same function. Finally, one might be tempted to think that the removed l2tp_tunnel_find() calls were harmless because they would return the same tunnel as the one held by l2tp_nl_cmd_session_create() anyway. But that tunnel might be removed and a new one created with same tunnel Id before the l2tp_tunnel_find() call. In this case l2tp_tunnel_find() would return the new tunnel which wouldn't be protected by the reference held by l2tp_nl_cmd_session_create(). Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-03l2tp: prevent creation of sessions on terminated tunnelsGuillaume Nault2-13/+32
l2tp_tunnel_destruct() sets tunnel->sock to NULL, then removes the tunnel from the pernet list and finally closes all its sessions. Therefore, it's possible to add a session to a tunnel that is still reachable, but for which tunnel->sock has already been reset. This can make l2tp_session_create() dereference a NULL pointer when calling sock_hold(tunnel->sock). This patch adds the .acpt_newsess field to struct l2tp_tunnel, which is used by l2tp_tunnel_closeall() to prevent addition of new sessions to tunnels. Resetting tunnel->sock is done after l2tp_tunnel_closeall() returned, so that l2tp_session_add_to_tunnel() can safely take a reference on it when .acpt_newsess is true. The .acpt_newsess field is modified in l2tp_tunnel_closeall(), rather than in l2tp_tunnel_destruct(), so that it benefits all tunnel removal mechanisms. E.g. on UDP tunnels, a session could be added to a tunnel after l2tp_udp_encap_destroy() proceeded. This would prevent the tunnel from being removed because of the references held by this new session on the tunnel and its socket. Even though the session could be removed manually later on, this defeats the purpose of commit 9980d001cec8 ("l2tp: add udp encap socket destroy handler"). Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28l2tp: hold tunnel used while creating sessions with netlinkGuillaume Nault1-9/+12
Use l2tp_tunnel_get() to retrieve tunnel, so that it can't go away on us. Otherwise l2tp_tunnel_destruct() might release the last reference count concurrently, thus freeing the tunnel while we're using it. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28l2tp: hold tunnel while handling genl TUNNEL_GET commandsGuillaume Nault1-12/+15
Use l2tp_tunnel_get() instead of l2tp_tunnel_find() so that we get a reference on the tunnel, preventing l2tp_tunnel_destruct() from freeing it from under us. Also move l2tp_tunnel_get() below nlmsg_new() so that we only take the reference when needed. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28l2tp: hold tunnel while handling genl tunnel updatesGuillaume Nault1-2/+4
We need to make sure the tunnel is not going to be destroyed by l2tp_tunnel_destruct() concurrently. Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-28l2tp: hold tunnel while processing genl delete commandGuillaume Nault1-2/+4
l2tp_nl_cmd_tunnel_delete() needs to take a reference on the tunnel, to prevent it from being concurrently freed by l2tp_tunnel_destruct(). Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
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