Commit Graph

3 Commits

Author SHA1 Message Date
Eric Dumazet
9981159fc3 wireguard: allowedips: fix use-after-free in root_remove_peer_lists
In the unlikely case a new node could not be allocated, we need to
remove @newnode from @peer->allowedips_list before freeing it.

syzbot reported:

BUG: KASAN: use-after-free in __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
Read of size 8 at addr ffff88809881a538 by task syz-executor.4/30133

CPU: 0 PID: 30133 Comm: syz-executor.4 Not tainted 5.5.0-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
 __list_del_entry include/linux/list.h:132 [inline]
 list_del include/linux/list.h:146 [inline]
 root_remove_peer_lists+0x24f/0x4b0 drivers/net/wireguard/allowedips.c:65
 wg_allowedips_free+0x232/0x390 drivers/net/wireguard/allowedips.c:300
 wg_peer_remove_all+0xd5/0x620 drivers/net/wireguard/peer.c:187
 wg_set_device+0xd01/0x1350 drivers/net/wireguard/netlink.c:542
 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
 genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 ____sys_sendmsg+0x753/0x880 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b399
Code: ad b6 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f99a9bcdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f99a9bce6d4 RCX: 000000000045b399
RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000000009ba R14: 00000000004cb2b8 R15: 0000000000000009

Allocated by task 30103:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:670 [inline]
 add+0x70a/0x1970 drivers/net/wireguard/allowedips.c:236
 wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320
 set_allowedip drivers/net/wireguard/netlink.c:343 [inline]
 set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468
 wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591
 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
 genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 ____sys_sendmsg+0x753/0x880 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 30103:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 add+0x12d2/0x1970 drivers/net/wireguard/allowedips.c:266
 wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320
 set_allowedip drivers/net/wireguard/netlink.c:343 [inline]
 set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468
 wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591
 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
 genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 ____sys_sendmsg+0x753/0x880 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809881a500
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 56 bytes inside of
 64-byte region [ffff88809881a500, ffff88809881a540)
The buggy address belongs to the page:
page:ffffea0002620680 refcount:1 mapcount:0 mapping:ffff8880aa400380 index:0x0
raw: 00fffe0000000200 ffffea000250b748 ffffea000254bac8 ffff8880aa400380
raw: 0000000000000000 ffff88809881a000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809881a400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809881a480: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff88809881a500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                        ^
 ffff88809881a580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809881a600: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc

Fixes: e7096c131e ("net: WireGuard secure network tunnel")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: wireguard@lists.zx2c4.com
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-05 14:14:18 +01:00
Wei Yongjun
d89ee7d5c7 wireguard: allowedips: use kfree_rcu() instead of call_rcu()
The callback function of call_rcu() just calls a kfree(), so we
can use kfree_rcu() instead of call_rcu() + callback function.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-16 19:22:22 -08:00
Jason A. Donenfeld
e7096c131e net: WireGuard secure network tunnel
WireGuard is a layer 3 secure networking tunnel made specifically for
the kernel, that aims to be much simpler and easier to audit than IPsec.
Extensive documentation and description of the protocol and
considerations, along with formal proofs of the cryptography, are
available at:

  * https://www.wireguard.com/
  * https://www.wireguard.com/papers/wireguard.pdf

This commit implements WireGuard as a simple network device driver,
accessible in the usual RTNL way used by virtual network drivers. It
makes use of the udp_tunnel APIs, GRO, GSO, NAPI, and the usual set of
networking subsystem APIs. It has a somewhat novel multicore queueing
system designed for maximum throughput and minimal latency of encryption
operations, but it is implemented modestly using workqueues and NAPI.
Configuration is done via generic Netlink, and following a review from
the Netlink maintainer a year ago, several high profile userspace tools
have already implemented the API.

This commit also comes with several different tests, both in-kernel
tests and out-of-kernel tests based on network namespaces, taking profit
of the fact that sockets used by WireGuard intentionally stay in the
namespace the WireGuard interface was originally created, exactly like
the semantics of userspace tun devices. See wireguard.com/netns/ for
pictures and examples.

The source code is fairly short, but rather than combining everything
into a single file, WireGuard is developed as cleanly separable files,
making auditing and comprehension easier. Things are laid out as
follows:

  * noise.[ch], cookie.[ch], messages.h: These implement the bulk of the
    cryptographic aspects of the protocol, and are mostly data-only in
    nature, taking in buffers of bytes and spitting out buffers of
    bytes. They also handle reference counting for their various shared
    pieces of data, like keys and key lists.

  * ratelimiter.[ch]: Used as an integral part of cookie.[ch] for
    ratelimiting certain types of cryptographic operations in accordance
    with particular WireGuard semantics.

  * allowedips.[ch], peerlookup.[ch]: The main lookup structures of
    WireGuard, the former being trie-like with particular semantics, an
    integral part of the design of the protocol, and the latter just
    being nice helper functions around the various hashtables we use.

  * device.[ch]: Implementation of functions for the netdevice and for
    rtnl, responsible for maintaining the life of a given interface and
    wiring it up to the rest of WireGuard.

  * peer.[ch]: Each interface has a list of peers, with helper functions
    available here for creation, destruction, and reference counting.

  * socket.[ch]: Implementation of functions related to udp_socket and
    the general set of kernel socket APIs, for sending and receiving
    ciphertext UDP packets, and taking care of WireGuard-specific sticky
    socket routing semantics for the automatic roaming.

  * netlink.[ch]: Userspace API entry point for configuring WireGuard
    peers and devices. The API has been implemented by several userspace
    tools and network management utility, and the WireGuard project
    distributes the basic wg(8) tool.

  * queueing.[ch]: Shared function on the rx and tx path for handling
    the various queues used in the multicore algorithms.

  * send.c: Handles encrypting outgoing packets in parallel on
    multiple cores, before sending them in order on a single core, via
    workqueues and ring buffers. Also handles sending handshake and cookie
    messages as part of the protocol, in parallel.

  * receive.c: Handles decrypting incoming packets in parallel on
    multiple cores, before passing them off in order to be ingested via
    the rest of the networking subsystem with GRO via the typical NAPI
    poll function. Also handles receiving handshake and cookie messages
    as part of the protocol, in parallel.

  * timers.[ch]: Uses the timer wheel to implement protocol particular
    event timeouts, and gives a set of very simple event-driven entry
    point functions for callers.

  * main.c, version.h: Initialization and deinitialization of the module.

  * selftest/*.h: Runtime unit tests for some of the most security
    sensitive functions.

  * tools/testing/selftests/wireguard/netns.sh: Aforementioned testing
    script using network namespaces.

This commit aims to be as self-contained as possible, implementing
WireGuard as a standalone module not needing much special handling or
coordination from the network subsystem. I expect for future
optimizations to the network stack to positively improve WireGuard, and
vice-versa, but for the time being, this exists as intentionally
standalone.

We introduce a menu option for CONFIG_WIREGUARD, as well as providing a
verbose debug log and self-tests via CONFIG_WIREGUARD_DEBUG.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: David Miller <davem@davemloft.net>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-08 17:48:42 -08:00