Commit Graph

15 Commits

Author SHA1 Message Date
Ido Schimmel
5299bca8c6 psample: Require 'CAP_NET_ADMIN' when joining "packets" group
[ Upstream commit 44ec98ea5e ]

The "psample" generic netlink family notifies sampled packets over the
"packets" multicast group. This is problematic since by default generic
netlink allows non-root users to listen to these notifications.

Fix by marking the group with the 'GENL_UNS_ADMIN_PERM' flag. This will
prevent non-root users or root without the 'CAP_NET_ADMIN' capability
(in the user namespace owning the network namespace) from joining the
group.

Tested using [1].

Before:

 # capsh -- -c ./psample_repo
 # capsh --drop=cap_net_admin -- -c ./psample_repo

After:

 # capsh -- -c ./psample_repo
 # capsh --drop=cap_net_admin -- -c ./psample_repo
 Failed to join "packets" multicast group

[1]
 $ cat psample.c
 #include <stdio.h>
 #include <netlink/genl/ctrl.h>
 #include <netlink/genl/genl.h>
 #include <netlink/socket.h>

 int join_grp(struct nl_sock *sk, const char *grp_name)
 {
 	int grp, err;

 	grp = genl_ctrl_resolve_grp(sk, "psample", grp_name);
 	if (grp < 0) {
 		fprintf(stderr, "Failed to resolve \"%s\" multicast group\n",
 			grp_name);
 		return grp;
 	}

 	err = nl_socket_add_memberships(sk, grp, NFNLGRP_NONE);
 	if (err) {
 		fprintf(stderr, "Failed to join \"%s\" multicast group\n",
 			grp_name);
 		return err;
 	}

 	return 0;
 }

 int main(int argc, char **argv)
 {
 	struct nl_sock *sk;
 	int err;

 	sk = nl_socket_alloc();
 	if (!sk) {
 		fprintf(stderr, "Failed to allocate socket\n");
 		return -1;
 	}

 	err = genl_connect(sk);
 	if (err) {
 		fprintf(stderr, "Failed to connect socket\n");
 		return err;
 	}

 	err = join_grp(sk, "config");
 	if (err)
 		return err;

 	err = join_grp(sk, "packets");
 	if (err)
 		return err;

 	return 0;
 }
 $ gcc -I/usr/include/libnl3 -lnl-3 -lnl-genl-3 -o psample_repo psample.c

Fixes: 6ae0a62861 ("net: Introduce psample, a new genetlink channel for packet sampling")
Reported-by: "The UK's National Cyber Security Centre (NCSC)" <security@ncsc.gov.uk>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231206213102.1824398-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13 18:36:37 +01:00
Ido Schimmel
07e1a5809b psample: Add additional metadata attributes
Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a 64-bit value
* End-to-end latency of the packet in nanoseconds resolution
* Software timestamp in nanoseconds resolution (always available)
* Packet's protocol. Needed for packet dissection in user space (always
  available)

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-14 15:00:43 -07:00
Ido Schimmel
a03e99d39f psample: Encapsulate packet metadata in a struct
Currently, callers of psample_sample_packet() pass three metadata
attributes: Ingress port, egress port and truncated size. Subsequent
patches are going to add more attributes (e.g., egress queue occupancy),
which also need an indication whether they are valid or not.

Encapsulate packet metadata in a struct in order to keep the number of
arguments reasonable.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-14 15:00:43 -07:00
Chris Mi
a93dcaada2 net: psample: Fix netlink skb length with tunnel info
Currently, the psample netlink skb is allocated with a size that does
not account for the nested 'PSAMPLE_ATTR_TUNNEL' attribute and the
padding required for the 64-bit attribute 'PSAMPLE_TUNNEL_KEY_ATTR_ID'.
This can result in failure to add attributes to the netlink skb due
to insufficient tail room. The following error message is printed to
the kernel log: "Could not create psample log message".

Fix this by adjusting the allocation size to take into account the
nested attribute and the padding.

Fixes: d8bed686ab ("net: psample: Add tunnel support")
CC: Yotam Gigi <yotam.gi@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Chris Mi <cmi@nvidia.com>
Link: https://lore.kernel.org/r/20210225075145.184314-1-cmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-02-25 09:49:46 -08:00
Jakub Kicinski
66a9b9287d genetlink: move to smaller ops wherever possible
Bulk of the genetlink users can use smaller ops, move them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-02 19:11:11 -07:00
Randy Dunlap
07a7f30819 net: psample: fix build error when CONFIG_INET is not enabled
Fix psample build error when CONFIG_INET is not set/enabled by
bracketing the tunnel code in #ifdef CONFIG_NET / #endif.

../net/psample/psample.c: In function ‘__psample_ip_tun_to_nlattr’:
../net/psample/psample.c:216:25: error: implicit declaration of function ‘ip_tunnel_info_opts’; did you mean ‘ip_tunnel_info_opts_set’? [-Werror=implicit-function-declaration]

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Yotam Gigi <yotam.gi@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-23 16:36:05 -07:00
Chris Mi
d8bed686ab net: psample: Add tunnel support
Currently, psample can only send the packet bits after decapsulation.
The tunnel information is lost. Add the tunnel support.

If the sampled packet has no tunnel info, the behavior is the same as
before. If it has, add a nested metadata field named PSAMPLE_ATTR_TUNNEL
and include the tunnel subfields if applicable.

Increase the metadata length for sampled packet with the tunnel info.
If new subfields of tunnel info should be included, update the metadata
length accordingly.

Signed-off-by: Chris Mi <chrism@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-21 17:04:07 -07:00
Nikolay Aleksandrov
7eb9d7675c net: psample: fix skb_over_panic
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>
2019-11-26 14:40:13 -08:00
Vlad Buslov
4a5da47d5c net: sched: take reference to psample group in flow_action infra
With recent patch set that removed rtnl lock dependency from cls hardware
offload API rtnl lock is only taken when reading action data and can be
released after action-specific data is parsed into intermediate
representation. However, sample action psample group is passed by pointer
without obtaining reference to it first, which makes it possible to
concurrently overwrite the action and deallocate object pointed by
psample_group pointer after rtnl lock is released but before driver
finished using the pointer.

To prevent such race condition, obtain reference to psample group while it
is used by flow_action infra. Extend psample API with function
psample_group_take() that increments psample group reference counter.
Extend struct tc_action_ops with new get_psample_group() API. Implement the
API for action sample using psample_group_take() and already existing
psample_group_put() as a destructor. Use it in tc_setup_flow_action() to
take reference to psample group pointed to by entry->sample.psample_group
and release it in tc_cleanup_flow_action().

Disable bh when taking psample_groups_lock. The lock is now taken while
holding action tcf_lock that is used by data path and requires bh to be
disabled, so doing the same for psample_groups_lock is necessary to
preserve SOFTIRQ-irq-safety.

Fixes: 918190f50e ("net: sched: flower: don't take rtnl lock for cls hw offloads API")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-16 09:18:03 +02:00
Vlad Buslov
dbf47a2a09 net: sched: act_sample: fix psample group handling on overwrite
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>
2019-08-28 15:53:51 -07:00
Thomas Gleixner
d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Johannes Berg
ef6243acb4 genetlink: optionally validate strictly/dumps
Add options to strictly validate messages and dump messages,
sometimes perhaps validating dump messages non-strictly may
be required, so add an option for that as well.

Since none of this can really be applied to existing commands,
set the options everwhere using the following spatch:

    @@
    identifier ops;
    expression X;
    @@
    struct genl_ops ops[] = {
    ...,
     {
            .cmd = X,
    +       .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
            ...
     },
    ...
    };

For new commands one should just not copy the .validate 'opt-out'
flags and thus get strict validation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:22 -04:00
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