linux-toradex.git/net/packet, branch v4.4.115

net/packet: fix a race in packet_bind() and packet_notifier()

2017-12-16T09:33:56+00:00

[ Upstream commit 15fe076edea787807a7cdc168df832544b58eba6 ]

syzbot reported crashes [1] and provided a C repro easing bug hunting.

When/if packet_do_bind() calls __unregister_prot_hook() and releases
po->bind_lock, another thread can run packet_notifier() and process an
NETDEV_UP event.

This calls register_prot_hook() and hooks again the socket right before
first thread is able to grab again po->bind_lock.

Fixes this issue by temporarily setting po->num to 0, as suggested by
David Miller.

[1]
dev_remove_pack: ffff8801bf16fa80 not found
------------[ cut here ]------------
kernel BUG at net/core/dev.c:7945!  ( BUG_ON(!list_empty(&dev->ptype_all)); )
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
device syz0 entered promiscuous mode
CPU: 0 PID: 3161 Comm: syzkaller404108 Not tainted 4.14.0+ #190
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cc57a500 task.stack: ffff8801cc588000
RIP: 0010:netdev_run_todo+0x772/0xae0 net/core/dev.c:7945
RSP: 0018:ffff8801cc58f598 EFLAGS: 00010293
RAX: ffff8801cc57a500 RBX: dffffc0000000000 RCX: ffffffff841f75b2
RDX: 0000000000000000 RSI: 1ffff100398b1ede RDI: ffff8801bf1f8810
device syz0 entered promiscuous mode
RBP: ffff8801cc58f898 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801bf1f8cd8
R13: ffff8801cc58f870 R14: ffff8801bf1f8780 R15: ffff8801cc58f7f0
FS:  0000000001716880(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020b13000 CR3: 0000000005e25000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:106
 tun_detach drivers/net/tun.c:670 [inline]
 tun_chr_close+0x49/0x60 drivers/net/tun.c:2845
 __fput+0x333/0x7f0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ae0 kernel/exit.c:865
 do_group_exit+0x149/0x400 kernel/exit.c:968
 SYSC_exit_group kernel/exit.c:979 [inline]
 SyS_exit_group+0x1d/0x20 kernel/exit.c:977
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x44ad19

Fixes: 30f7ea1c2b5f ("packet: race condition in packet_bind")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Cc: Francesco Ruggeri 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: fix crash in fanout_demux_rollover()

2017-12-16T09:33:56+00:00

syzkaller found a race condition fanout_demux_rollover() while removing
a packet socket from a fanout group.

po->rollover is read and operated on during packet_rcv_fanout(), via
fanout_demux_rollover(), but the pointer is currently cleared before the
synchronization in packet_release().   It is safer to delay the cleanup
until after synchronize_net() has been called, ensuring all calls to
packet_rcv_fanout() for this socket have finished.

To further simplify synchronization around the rollover structure, set
po->rollover in fanout_add() only if there are no errors.  This removes
the need for rcu in the struct and in the call to
packet_getsockopt(..., PACKET_ROLLOVER_STATS, ...).

Crashing stack trace:
 fanout_demux_rollover+0xb6/0x4d0 net/packet/af_packet.c:1392
 packet_rcv_fanout+0x649/0x7c8 net/packet/af_packet.c:1487
 dev_queue_xmit_nit+0x835/0xc10 net/core/dev.c:1953
 xmit_one net/core/dev.c:2975 [inline]
 dev_hard_start_xmit+0x16b/0xac0 net/core/dev.c:2995
 __dev_queue_xmit+0x17a4/0x2050 net/core/dev.c:3476
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3509
 neigh_connected_output+0x489/0x720 net/core/neighbour.c:1379
 neigh_output include/net/neighbour.h:482 [inline]
 ip6_finish_output2+0xad1/0x22a0 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip6_output+0x1f4/0x850 net/ipv6/ip6_output.c:163
 dst_output include/net/dst.h:459 [inline]
 NF_HOOK.constprop.35+0xff/0x630 include/linux/netfilter.h:250
 mld_sendpack+0x6a8/0xcc0 net/ipv6/mcast.c:1660
 mld_send_initial_cr.part.24+0x103/0x150 net/ipv6/mcast.c:2072
 mld_send_initial_cr net/ipv6/mcast.c:2056 [inline]
 ipv6_mc_dad_complete+0x99/0x130 net/ipv6/mcast.c:2079
 addrconf_dad_completed+0x595/0x970 net/ipv6/addrconf.c:4039
 addrconf_dad_work+0xac9/0x1160 net/ipv6/addrconf.c:3971
 process_one_work+0xbf0/0x1bc0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x35e/0x430 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:432

Fixes: 0648ab70afe6 ("packet: rollover prepare: per-socket state")
Fixes: 509c7a1ecc860 ("packet: avoid panic in packet_getsockopt()")
Reported-by: syzbot 
Signed-off-by: Mike Maloney 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: avoid panic in packet_getsockopt()

2017-11-18T10:11:06+00:00

[ Upstream commit 509c7a1ecc8601f94ffba8a00889fefb239c00c6 ]

syzkaller got crashes in packet_getsockopt() processing
PACKET_ROLLOVER_STATS command while another thread was managing
to change po->rollover

Using RCU will fix this bug. We might later add proper RCU annotations
for sparse sake.

In v2: I replaced kfree(rollover) in fanout_add() to kfree_rcu()
variant, as spotted by John.

Fixes: a9b6391814d5 ("packet: rollover statistics")
Signed-off-by: Eric Dumazet 
Cc: Willem de Bruijn 
Cc: John Sperbeck 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: only test po->has_vnet_hdr once in packet_snd

2017-10-21T15:09:03+00:00

[ Upstream commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 ]

Packet socket option po->has_vnet_hdr can be updated concurrently with
other operations if no ring is attached.

Do not test the option twice in packet_snd, as the value may change in
between calls. A race on setsockopt disable may cause a packet > mtu
to be sent without having GSO options set.

Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.")
Signed-off-by: Willem de Bruijn 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: in packet_do_bind, test fanout with bind_lock held

2017-10-21T15:09:03+00:00

[ Upstream commit 4971613c1639d8e5f102c4e797c3bf8f83a5a69e ]

Once a socket has po->fanout set, it remains a member of the group
until it is destroyed. The prot_hook must be constant and identical
across sockets in the group.

If fanout_add races with packet_do_bind between the test of po->fanout
and taking the lock, the bind call may make type or dev inconsistent
with that of the fanout group.

Hold po->bind_lock when testing po->fanout to avoid this race.

I had to introduce artificial delay (local_bh_enable) to actually
observe the race.

Fixes: dc99f600698d ("packet: Add fanout support.")
Signed-off-by: Willem de Bruijn 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: hold bind lock when rebinding to fanout hook

2017-10-21T15:09:02+00:00

[ Upstream commit 008ba2a13f2d04c947adc536d19debb8fe66f110 ]

Packet socket bind operations must hold the po->bind_lock. This keeps
po->running consistent with whether the socket is actually on a ptype
list to receive packets.

fanout_add unbinds a socket and its packet_rcv/tpacket_rcv call, then
binds the fanout object to receive through packet_rcv_fanout.

Make it hold the po->bind_lock when testing po->running and rebinding.
Else, it can race with other rebind operations, such as that in
packet_set_ring from packet_rcv to tpacket_rcv. Concurrent updates
can result in a socket being added to a fanout group twice, causing
use-after-free KASAN bug reports, among others.

Reported independently by both trinity and syzkaller.
Verified that the syzkaller reproducer passes after this patch.

Fixes: dc99f600698d ("packet: Add fanout support.")
Reported-by: nixioaming 
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/packet: check length in getsockopt() called with PACKET_HDRLEN

2017-10-08T08:14:18+00:00

[ Upstream commit fd2c83b35752f0a8236b976978ad4658df14a59f ]

In the case getsockopt() is called with PACKET_HDRLEN and optlen < 4
|val| remains uninitialized and the syscall may behave differently
depending on its value, and even copy garbage to userspace on certain
architectures. To fix this we now return -EINVAL if optlen is too small.

This bug has been detected with KMSAN.

Signed-off-by: Alexander Potapenko 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

packet: fix tp_reserve race in packet_set_ring

2017-08-13T02:29:08+00:00

[ Upstream commit c27927e372f0785f3303e8fad94b85945e2c97b7 ]

Updates to tp_reserve can race with reads of the field in
packet_set_ring. Avoid this by holding the socket lock during
updates in setsockopt PACKET_RESERVE.

This bug was discovered by syzkaller.

Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
Reported-by: Andrey Konovalov 
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

packet: fix use-after-free in prb_retire_rx_blk_timer_expired()

2017-08-11T16:08:53+00:00

[ Upstream commit c800aaf8d869f2b9b47b10c5c312fe19f0a94042 ]

There are multiple reports showing we have a use-after-free in
the timer prb_retire_rx_blk_timer_expired(), where we use struct
tpacket_kbdq_core::pkbdq, a pg_vec, after it gets freed by
free_pg_vec().

The interesting part is it is not freed via packet_release() but
via packet_setsockopt(), which means we are not closing the socket.
Looking into the big and fat function packet_set_ring(), this could
happen if we satisfy the following conditions:

1. closing == 0, not on packet_release() path
2. req->tp_block_nr == 0, we don't allocate a new pg_vec
3. rx_ring->pg_vec is already set as V3, which means we already called
   packet_set_ring() wtih req->tp_block_nr > 0 previously
4. req->tp_frame_nr == 0, pass sanity check
5. po->mapped == 0, never called mmap()

In this scenario we are clearing the old rx_ring->pg_vec, so we need
to free this pg_vec, but we don't stop the timer on this path because
of closing==0.

The timer has to be stopped as long as we need to free pg_vec, therefore
the check on closing!=0 is wrong, we should check pg_vec!=NULL instead.

Thanks to liujian for testing different fixes.

Reported-by: alexander.levin@verizon.com
Reported-by: Dave Jones 
Reported-by: liujian (CE) 
Tested-by: liujian (CE) 
Cc: Ding Tianhong 
Cc: Willem de Bruijn 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/packet: fix overflow in check for tp_reserve

2017-05-03T04:19:51+00:00

[ Upstream commit bcc5364bdcfe131e6379363f089e7b4108d35b70 ]

When calculating po->tp_hdrlen + po->tp_reserve the result can overflow.

Fix by checking that tp_reserve <= INT_MAX on assign.

Signed-off-by: Andrey Konovalov 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman