linux-stable.git/net/l2tp, branch v5.8.2

l2tp: remove skb_dst_set() from l2tp_xmit_skb()

2020-07-08T22:24:33+00:00

In the tx path of l2tp, l2tp_xmit_skb() calls skb_dst_set() to set
skb's dst. However, it will eventually call inet6_csk_xmit() or
ip_queue_xmit() where skb's dst will be overwritten by:

   skb_dst_set_noref(skb, dst);

without releasing the old dst in skb. Then it causes dst/dev refcnt leak:

  unregister_netdevice: waiting for eth0 to become free. Usage count = 1

This can be reproduced by simply running:

  # modprobe l2tp_eth && modprobe l2tp_ip
  # sh ./tools/testing/selftests/net/l2tp.sh

So before going to inet6_csk_xmit() or ip_queue_xmit(), skb's dst
should be dropped. This patch is to fix it by removing skb_dst_set()
from l2tp_xmit_skb() and moving skb_dst_drop() into l2tp_xmit_core().

Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core")
Reported-by: Hangbin Liu 
Signed-off-by: Xin Long 
Acked-by: James Chapman 
Tested-by: James Chapman 
Signed-off-by: David S. Miller

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21+00:00

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2020-06-01T00:48:46+00:00

xdp_umem.c had overlapping changes between the 64-bit math fix
for the calculation of npgs and the removal of the zerocopy
memory type which got rid of the chunk_size_nohdr member.

The mlx5 Kconfig conflict is a case where we just take the
net-next copy of the Kconfig entry dependency as it takes on
the ESWITCH dependency by one level of indirection which is
what the 'net' conflicting change is trying to ensure.

Signed-off-by: David S. Miller

l2tp: add sk_family checks to l2tp_validate_socket

2020-05-31T04:56:55+00:00

syzbot was able to trigger a crash after using an ISDN socket
and fool l2tp.

Fix this by making sure the UDP socket is of the proper family.

BUG: KASAN: slab-out-of-bounds in setup_udp_tunnel_sock+0x465/0x540 net/ipv4/udp_tunnel.c:78
Write of size 1 at addr ffff88808ed0c590 by task syz-executor.5/3018

CPU: 0 PID: 3018 Comm: syz-executor.5 Not tainted 5.7.0-rc6-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:382
 __kasan_report.cold+0x20/0x38 mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 setup_udp_tunnel_sock+0x465/0x540 net/ipv4/udp_tunnel.c:78
 l2tp_tunnel_register+0xb15/0xdd0 net/l2tp/l2tp_core.c:1523
 l2tp_nl_cmd_tunnel_create+0x4b2/0xa60 net/l2tp/l2tp_netlink.c:249
 genl_family_rcv_msg_doit net/netlink/genetlink.c:673 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:718 [inline]
 genl_rcv_msg+0x627/0xdf0 net/netlink/genetlink.c:735
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:746
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007effe76edc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004fe1c0 RCX: 000000000045ca29
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000094e R14: 00000000004d5d00 R15: 00007effe76ee6d4

Allocated by task 3018:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x161/0x7a0 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 sk_prot_alloc+0x223/0x2f0 net/core/sock.c:1612
 sk_alloc+0x36/0x1100 net/core/sock.c:1666
 data_sock_create drivers/isdn/mISDN/socket.c:600 [inline]
 mISDN_sock_create+0x272/0x400 drivers/isdn/mISDN/socket.c:796
 __sock_create+0x3cb/0x730 net/socket.c:1428
 sock_create net/socket.c:1479 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1521
 __do_sys_socket net/socket.c:1530 [inline]
 __se_sys_socket net/socket.c:1528 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1528
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 2484:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 kvfree+0x42/0x50 mm/util.c:603
 __free_fdtable+0x2d/0x70 fs/file.c:31
 put_files_struct fs/file.c:420 [inline]
 put_files_struct+0x248/0x2e0 fs/file.c:413
 exit_files+0x7e/0xa0 fs/file.c:445
 do_exit+0xb04/0x2dd0 kernel/exit.c:791
 do_group_exit+0x125/0x340 kernel/exit.c:894
 get_signal+0x47b/0x24e0 kernel/signal.c:2739
 do_signal+0x81/0x2240 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff88808ed0c000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1424 bytes inside of
 2048-byte region [ffff88808ed0c000, ffff88808ed0c800)
The buggy address belongs to the page:
page:ffffea00023b4300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002838208 ffffea00015ba288 ffff8880aa000e00
raw: 0000000000000000 ffff88808ed0c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808ed0c480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808ed0c500: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808ed0c580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88808ed0c600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808ed0c680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Fixes: 6b9f34239b00 ("l2tp: fix races in tunnel creation")
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Eric Dumazet 
Cc: James Chapman 
Cc: Guillaume Nault 
Reported-by: syzbot 
Acked-by: Guillaume Nault 
Signed-off-by: David S. Miller

l2tp: do not use inet_hash()/inet_unhash()

2020-05-31T04:55:16+00:00

syzbot recently found a way to crash the kernel [1]

Issue here is that inet_hash() & inet_unhash() are currently
only meant to be used by TCP & DCCP, since only these protocols
provide the needed hashinfo pointer.

L2TP uses a single list (instead of a hash table)

This old bug became an issue after commit 610236587600
("bpf: Add new cgroup attach type to enable sock modifications")
since after this commit, sk_common_release() can be called
while the L2TP socket is still considered 'hashed'.

general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 7063 Comm: syz-executor654 Not tainted 5.7.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:inet_unhash+0x11f/0x770 net/ipv4/inet_hashtables.c:600
Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e dd 04 00 00 48 8d 7d 08 44 8b 73 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 55 05 00 00 48 8d 7d 14 4c 8b 6d 08 48 b8 00 00
RSP: 0018:ffffc90001777d30 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88809a6df940 RCX: ffffffff8697c242
RDX: 0000000000000001 RSI: ffffffff8697c251 RDI: 0000000000000008
RBP: 0000000000000000 R08: ffff88809f3ae1c0 R09: fffffbfff1514cc1
R10: ffffffff8a8a6607 R11: fffffbfff1514cc0 R12: ffff88809a6df9b0
R13: 0000000000000007 R14: 0000000000000000 R15: ffffffff873a4d00
FS:  0000000001d2b880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006cd090 CR3: 000000009403a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sk_common_release+0xba/0x370 net/core/sock.c:3210
 inet_create net/ipv4/af_inet.c:390 [inline]
 inet_create+0x966/0xe00 net/ipv4/af_inet.c:248
 __sock_create+0x3cb/0x730 net/socket.c:1428
 sock_create net/socket.c:1479 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1521
 __do_sys_socket net/socket.c:1530 [inline]
 __se_sys_socket net/socket.c:1528 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1528
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x441e29
Code: e8 fc b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdce184148 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441e29
RDX: 0000000000000073 RSI: 0000000000000002 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000402c30 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 23b6578228ce553e ]---
RIP: 0010:inet_unhash+0x11f/0x770 net/ipv4/inet_hashtables.c:600
Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e dd 04 00 00 48 8d 7d 08 44 8b 73 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 55 05 00 00 48 8d 7d 14 4c 8b 6d 08 48 b8 00 00
RSP: 0018:ffffc90001777d30 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88809a6df940 RCX: ffffffff8697c242
RDX: 0000000000000001 RSI: ffffffff8697c251 RDI: 0000000000000008
RBP: 0000000000000000 R08: ffff88809f3ae1c0 R09: fffffbfff1514cc1
R10: ffffffff8a8a6607 R11: fffffbfff1514cc0 R12: ffff88809a6df9b0
R13: 0000000000000007 R14: 0000000000000000 R15: ffffffff873a4d00
FS:  0000000001d2b880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006cd090 CR3: 000000009403a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support")
Signed-off-by: Eric Dumazet 
Cc: James Chapman 
Cc: Andrii Nakryiko 
Reported-by: syzbot+3610d489778b57cc8031@syzkaller.appspotmail.com

ipv6: move SIOCADDRT and SIOCDELRT handling into ->compat_ioctl

2020-05-19T00:35:02+00:00

To prepare removing the global routing_ioctl hack start lifting the code
into a newly added ipv6 ->compat_ioctl handler.

Signed-off-by: Christoph Hellwig 
Signed-off-by: David S. Miller

net: partially revert dynamic lockdep key changes

2020-05-04T19:05:56+00:00

This patch reverts the folowing commits:

commit 064ff66e2bef84f1153087612032b5b9eab005bd
"bonding: add missing netdev_update_lockdep_key()"

commit 53d374979ef147ab51f5d632dfe20b14aebeccd0
"net: avoid updating qdisc_xmit_lock_key in netdev_update_lockdep_key()"

commit 1f26c0d3d24125992ab0026b0dab16c08df947c7
"net: fix kernel-doc warning in "

commit ab92d68fc22f9afab480153bd82a20f6e2533769
"net: core: add generic lockdep keys"

but keeps the addr_list_lock_key because we still lock
addr_list_lock nestedly on stack devices, unlikely xmit_lock
this is safe because we don't take addr_list_lock on any fast
path.

Reported-and-tested-by: syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com
Cc: Dmitry Vyukov 
Cc: Taehee Yoo 
Signed-off-by: Cong Wang 
Acked-by: Taehee Yoo 
Signed-off-by: David S. Miller

l2tp: Allow management of tunnels and session in user namespace

2020-04-08T21:30:46+00:00

Creation and management of L2TPv3 tunnels and session through netlink
requires CAP_NET_ADMIN. However, a process with CAP_NET_ADMIN in a
non-initial user namespace gets an EPERM due to the use of the
genetlink GENL_ADMIN_PERM flag. Thus, management of L2TP VPNs inside
an unprivileged container won't work.

We replaced the GENL_ADMIN_PERM by the GENL_UNS_ADMIN_PERM flag
similar to other network modules which also had this problem, e.g.,
openvswitch (commit 4a92602aa1cd "openvswitch: allow management from
inside user namespaces") and nl80211 (commit 5617c6cd6f844 "nl80211:
Allow privileged operations from user namespaces").

I tested this in the container runtime trustm3 (trustm3.github.io)
and was able to create l2tp tunnels and sessions in unpriviliged
(user namespaced) containers using a private network namespace.
For other runtimes such as docker or lxc this should work, too.

Signed-off-by: Michael Weiß 
Signed-off-by: David S. Miller

l2tp: Replace zero-length array with flexible-array member

2020-02-28T20:08:37+00:00

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

Lastly, fix the following checkpatch warning:
CHECK: Prefer kernel type 'u8' over 'uint8_t'
#50: FILE: net/l2tp/l2tp_core.h:119:
+	uint8_t			priv[];	/* private data */

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: David S. Miller

l2tp: Allow duplicate session creation with UDP

2020-02-04T11:35:49+00:00

In the past it was possible to create multiple L2TPv3 sessions with the
same session id as long as the sessions belonged to different tunnels.
The resulting sessions had issues when used with IP encapsulated tunnels,
but worked fine with UDP encapsulated ones. Some applications began to
rely on this behaviour to avoid having to negotiate unique session ids.

Some time ago a change was made to require session ids to be unique across
all tunnels, breaking the applications making use of this "feature".

This change relaxes the duplicate session id check to allow duplicates
if both of the colliding sessions belong to UDP encapsulated tunnels.

Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation")
Signed-off-by: Ridge Kennedy 
Acked-by: James Chapman 
Signed-off-by: David S. Miller