Commit graph

5 commits

Author SHA1 Message Date
Nikolay Aleksandrov
4f8bd02b6f net: psample: fix skb_over_panic
[ Upstream commit 7eb9d7675c08937cd11d32b0b40442d4d731c5ee ]

We need to calculate the skb size correctly otherwise we risk triggering
skb_over_panic[1]. The issue is that data_len is added to the skb in a
nl attribute, but we don't account for its header size (nlattr 4 bytes)
and alignment. We account for it when calculating the total size in
the > PSAMPLE_MAX_PACKET_SIZE comparison correctly, but not when
allocating after that. The fix is simple - use nla_total_size() for
data_len when allocating.

To reproduce:
 $ tc qdisc add dev eth1 clsact
 $ tc filter add dev eth1 egress matchall action sample rate 1 group 1 trunc 129
 $ mausezahn eth1 -b bcast -a rand -c 1 -p 129
 < skb_over_panic BUG(), tail is 4 bytes past skb->end >

[1] Trace:
 [   50.459526][ T3480] skbuff: skb_over_panic: text:(____ptrval____) len:196 put:136 head:(____ptrval____) data:(____ptrval____) tail:0xc4 end:0xc0 dev:<NULL>
 [   50.474339][ T3480] ------------[ cut here ]------------
 [   50.481132][ T3480] kernel BUG at net/core/skbuff.c:108!
 [   50.486059][ T3480] invalid opcode: 0000 [#1] PREEMPT SMP
 [   50.489463][ T3480] CPU: 3 PID: 3480 Comm: mausezahn Not tainted 5.4.0-rc7 #108
 [   50.492844][ T3480] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
 [   50.496551][ T3480] RIP: 0010:skb_panic+0x79/0x7b
 [   50.498261][ T3480] Code: bc 00 00 00 41 57 4c 89 e6 48 c7 c7 90 29 9a 83 4c 8b 8b c0 00 00 00 50 8b 83 b8 00 00 00 50 ff b3 c8 00 00 00 e8 ae ef c0 fe <0f> 0b e8 2f df c8 fe 48 8b 55 08 44 89 f6 4c 89 e7 48 c7 c1 a0 22
 [   50.504111][ T3480] RSP: 0018:ffffc90000447a10 EFLAGS: 00010282
 [   50.505835][ T3480] RAX: 0000000000000087 RBX: ffff888039317d00 RCX: 0000000000000000
 [   50.507900][ T3480] RDX: 0000000000000000 RSI: ffffffff812716e1 RDI: 00000000ffffffff
 [   50.509820][ T3480] RBP: ffffc90000447a60 R08: 0000000000000001 R09: 0000000000000000
 [   50.511735][ T3480] R10: ffffffff81d4f940 R11: 0000000000000000 R12: ffffffff834a22b0
 [   50.513494][ T3480] R13: ffffffff82c10433 R14: 0000000000000088 R15: ffffffff838a8084
 [   50.515222][ T3480] FS:  00007f3536462700(0000) GS:ffff88803eac0000(0000) knlGS:0000000000000000
 [   50.517135][ T3480] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [   50.518583][ T3480] CR2: 0000000000442008 CR3: 000000003b222000 CR4: 00000000000006e0
 [   50.520723][ T3480] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 [   50.522709][ T3480] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 [   50.524450][ T3480] Call Trace:
 [   50.525214][ T3480]  skb_put.cold+0x1b/0x1b
 [   50.526171][ T3480]  psample_sample_packet+0x1d3/0x340
 [   50.527307][ T3480]  tcf_sample_act+0x178/0x250
 [   50.528339][ T3480]  tcf_action_exec+0xb1/0x190
 [   50.529354][ T3480]  mall_classify+0x67/0x90
 [   50.530332][ T3480]  tcf_classify+0x72/0x160
 [   50.531286][ T3480]  __dev_queue_xmit+0x3db/0xd50
 [   50.532327][ T3480]  dev_queue_xmit+0x18/0x20
 [   50.533299][ T3480]  packet_sendmsg+0xee7/0x2090
 [   50.534331][ T3480]  sock_sendmsg+0x54/0x70
 [   50.535271][ T3480]  __sys_sendto+0x148/0x1f0
 [   50.536252][ T3480]  ? tomoyo_file_ioctl+0x23/0x30
 [   50.537334][ T3480]  ? ksys_ioctl+0x5e/0xb0
 [   50.540068][ T3480]  __x64_sys_sendto+0x2a/0x30
 [   50.542810][ T3480]  do_syscall_64+0x73/0x1f0
 [   50.545383][ T3480]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 [   50.548477][ T3480] RIP: 0033:0x7f35357d6fb3
 [   50.551020][ T3480] Code: 48 8b 0d 18 90 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d f9 d3 20 00 00 75 13 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 eb f6 ff ff 48 89 04 24
 [   50.558547][ T3480] RSP: 002b:00007ffe0c7212c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
 [   50.561870][ T3480] RAX: ffffffffffffffda RBX: 0000000001dac010 RCX: 00007f35357d6fb3
 [   50.565142][ T3480] RDX: 0000000000000082 RSI: 0000000001dac2a2 RDI: 0000000000000003
 [   50.568469][ T3480] RBP: 00007ffe0c7212f0 R08: 00007ffe0c7212d0 R09: 0000000000000014
 [   50.571731][ T3480] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000082
 [   50.574961][ T3480] R13: 0000000001dac2a2 R14: 0000000000000001 R15: 0000000000000003
 [   50.578170][ T3480] Modules linked in: sch_ingress virtio_net
 [   50.580976][ T3480] ---[ end trace 61a515626a595af6 ]---

CC: Yotam Gigi <yotamg@mellanox.com>
CC: Jiri Pirko <jiri@mellanox.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: Simon Horman <simon.horman@netronome.com>
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
Fixes: 6ae0a62861 ("net: Introduce psample, a new genetlink channel for packet sampling")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05 09:21:30 +01:00
Vlad Buslov
5ff0ab0c66 net: sched: act_sample: fix psample group handling on overwrite
[ Upstream commit dbf47a2a094edf58983265e323ca4bdcdb58b5ee ]

Action sample doesn't properly handle psample_group pointer in overwrite
case. Following issues need to be fixed:

- In tcf_sample_init() function RCU_INIT_POINTER() is used to set
  s->psample_group, even though we neither setting the pointer to NULL, nor
  preventing concurrent readers from accessing the pointer in some way.
  Use rcu_swap_protected() instead to safely reset the pointer.

- Old value of s->psample_group is not released or deallocated in any way,
  which results resource leak. Use psample_group_put() on non-NULL value
  obtained with rcu_swap_protected().

- The function psample_group_put() that released reference to struct
  psample_group pointed by rcu-pointer s->psample_group doesn't respect rcu
  grace period when deallocating it. Extend struct psample_group with rcu
  head and use kfree_rcu when freeing it.

Fixes: 5c5670fae4 ("net/sched: Introduce sample tc action")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-10 10:33:38 +01:00
Yotam Gigi
f1fd20c361 MAINTAINERS: Update Yotam's E-mail
For the time being I will be available in my private mail. Update both the
MAINTAINERS file and the individual modules MODULE_AUTHOR directive with
the new address.

Signed-off-by: Yotam Gigi <yotam.gi@gmail.com>
Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01 12:19:03 +09:00
Johannes Berg
4df864c1d9 networking: make skb_put & friends return void pointers
It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions (skb_put, __skb_put and pskb_put) return void *
and remove all the casts across the tree, adding a (u8 *) cast only
where the unsigned char pointer was used directly, all done with the
following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_put, __skb_put };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_put, __skb_put };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

which actually doesn't cover pskb_put since there are only three
users overall.

A handful of stragglers were converted manually, notably a macro in
drivers/isdn/i4l/isdn_bsdcomp.c and, oddly enough, one of the many
instances in net/bluetooth/hci_sock.c. In the former file, I also
had to fix one whitespace problem spatch introduced.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16 11:48:39 -04:00
Yotam Gigi
6ae0a62861 net: Introduce psample, a new genetlink channel for packet sampling
Add a general way for kernel modules to sample packets, without being tied
to any specific subsystem. This netlink channel can be used by tc,
iptables, etc. and allow to standardize packet sampling in the kernel.

For every sampled packet, the psample module adds the following metadata
fields:

PSAMPLE_ATTR_IIFINDEX - the packets input ifindex, if applicable

PSAMPLE_ATTR_OIFINDEX - the packet output ifindex, if applicable

PSAMPLE_ATTR_ORIGSIZE - the packet's original size, in case it has been
   truncated during sampling

PSAMPLE_ATTR_SAMPLE_GROUP - the packet's sample group, which is set by the
   user who initiated the sampling. This field allows the user to
   differentiate between several samplers working simultaneously and
   filter packets relevant to him

PSAMPLE_ATTR_GROUP_SEQ - sequence counter of last sent packet. The
   sequence is kept for each group

PSAMPLE_ATTR_SAMPLE_RATE - the sampling rate used for sampling the packets

PSAMPLE_ATTR_DATA - the actual packet bits

The sampled packets are sent to the PSAMPLE_NL_MCGRP_SAMPLE multicast
group. In addition, add the GET_GROUPS netlink command which allows the
user to see the current sample groups, their refcount and sequence number.
This command currently supports only netlink dump mode.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-24 13:44:28 -05:00