linux.git/net/core/fib_rules.c, branch v4.13

net: set fib rule refcount after malloc

2017-07-13T20:43:54+00:00

The configure callback of fib_rules_ops can change the refcnt of a
fib rule. For instance, mlxsw takes a refcnt when adding the processing
of the rule to a work queue. Thus the rule refcnt can not be reset to
to 1 afterwards. Move the refcnt setting to after the allocation.

Fixes: 5361e209dd30 ("net: avoid one splat in fib_nl_delrule()")
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

net: avoid one splat in fib_nl_delrule()

2017-07-03T10:29:14+00:00

We need to use refcount_set() on a newly created rule to avoid
following error :

[   64.601749] ------------[ cut here ]------------
[   64.601757] WARNING: CPU: 0 PID: 6476 at lib/refcount.c:184 refcount_sub_and_test+0x75/0xa0
[   64.601758] Modules linked in: w1_therm wire cdc_acm ehci_pci ehci_hcd mlx4_en ib_uverbs mlx4_ib ib_core mlx4_core
[   64.601769] CPU: 0 PID: 6476 Comm: ip Tainted: G        W       4.12.0-smp-DEV #274
[   64.601771] task: ffff8837bf482040 task.stack: ffff8837bdc08000
[   64.601773] RIP: 0010:refcount_sub_and_test+0x75/0xa0
[   64.601774] RSP: 0018:ffff8837bdc0f5c0 EFLAGS: 00010286
[   64.601776] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000
[   64.601777] RDX: 0000000000000026 RSI: 0000000000000096 RDI: ffffed06f7b81eae
[   64.601778] RBP: ffff8837bdc0f5d0 R08: 0000000000000004 R09: fffffbfff4a54c25
[   64.601779] R10: 00000000cbc500e5 R11: ffffffffa52a6128 R12: ffff881febcf6f24
[   64.601779] R13: ffff881fbf4eaf00 R14: ffff881febcf6f80 R15: ffff8837d7a4ed00
[   64.601781] FS:  00007ff5a2f6b700(0000) GS:ffff881fff800000(0000) knlGS:0000000000000000
[   64.601782] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   64.601783] CR2: 00007ffcdc70d000 CR3: 0000001f9c91e000 CR4: 00000000001406f0
[   64.601783] Call Trace:
[   64.601786]  refcount_dec_and_test+0x11/0x20
[   64.601790]  fib_nl_delrule+0xc39/0x1630
[   64.601793]  ? is_bpf_text_address+0xe/0x20
[   64.601795]  ? fib_nl_newrule+0x25e0/0x25e0
[   64.601798]  ? depot_save_stack+0x133/0x470
[   64.601801]  ? ns_capable+0x13/0x20
[   64.601803]  ? __netlink_ns_capable+0xcc/0x100
[   64.601806]  rtnetlink_rcv_msg+0x23a/0x6a0
[   64.601808]  ? rtnl_newlink+0x1630/0x1630
[   64.601811]  ? memset+0x31/0x40
[   64.601813]  netlink_rcv_skb+0x2d7/0x440
[   64.601815]  ? rtnl_newlink+0x1630/0x1630
[   64.601816]  ? netlink_ack+0xaf0/0xaf0
[   64.601818]  ? kasan_unpoison_shadow+0x35/0x50
[   64.601820]  ? __kmalloc_node_track_caller+0x4c/0x70
[   64.601821]  rtnetlink_rcv+0x28/0x30
[   64.601823]  netlink_unicast+0x422/0x610
[   64.601824]  ? netlink_attachskb+0x650/0x650
[   64.601826]  netlink_sendmsg+0x7b7/0xb60
[   64.601828]  ? netlink_unicast+0x610/0x610
[   64.601830]  ? netlink_unicast+0x610/0x610
[   64.601832]  sock_sendmsg+0xba/0xf0
[   64.601834]  ___sys_sendmsg+0x6a9/0x8c0
[   64.601835]  ? copy_msghdr_from_user+0x520/0x520
[   64.601837]  ? __alloc_pages_nodemask+0x160/0x520
[   64.601839]  ? memcg_write_event_control+0xd60/0xd60
[   64.601841]  ? __alloc_pages_slowpath+0x1d50/0x1d50
[   64.601843]  ? kasan_slab_free+0x71/0xc0
[   64.601845]  ? mem_cgroup_commit_charge+0xb2/0x11d0
[   64.601847]  ? lru_cache_add_active_or_unevictable+0x7d/0x1a0
[   64.601849]  ? __handle_mm_fault+0x1af8/0x2810
[   64.601851]  ? may_open_dev+0xc0/0xc0
[   64.601852]  ? __pmd_alloc+0x2c0/0x2c0
[   64.601853]  ? __fdget+0x13/0x20
[   64.601855]  __sys_sendmsg+0xc6/0x150
[   64.601856]  ? __sys_sendmsg+0xc6/0x150
[   64.601857]  ? SyS_shutdown+0x170/0x170
[   64.601859]  ? handle_mm_fault+0x28a/0x650
[   64.601861]  SyS_sendmsg+0x12/0x20
[   64.601863]  entry_SYSCALL_64_fastpath+0x13/0x94

Fixes: 717d1e993ad8 ("net: convert fib_rule.refcnt from atomic_t to refcount_t")
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: convert fib_rule.refcnt from atomic_t to refcount_t

2017-07-01T14:39:09+00:00

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova 
Signed-off-by: Hans Liljestrand 
Signed-off-by: Kees Cook 
Signed-off-by: David Windsor 
Signed-off-by: David S. Miller

fib_rules: Resolve goto rules target on delete

2017-06-20T16:39:18+00:00

We should avoid marking goto rules unresolved when their
target is actually reachable after rule deletion.

Consolder following sample scenario:

  # ip -4 ru sh
  0:      from all lookup local
  32000:  from all goto 32100
  32100:  from all lookup main
  32100:  from all lookup default
  32766:  from all lookup main
  32767:  from all lookup default

  # ip -4 ru del pref 32100 table main
  # ip -4 ru sh
  0:      from all lookup local
  32000:  from all goto 32100 [unresolved]
  32100:  from all lookup default
  32766:  from all lookup main
  32767:  from all lookup default

After removal of first rule with preference 32100 we
mark all goto rules as unreachable, even when rule with
same preference as removed one still present.

Check if next rule with same preference is available
and make all rules with goto action pointing to it.

Signed-off-by: Serhey Popovych 
Signed-off-by: David S. Miller

fib_rules: fix error return code

2017-04-27T20:35:57+00:00

Fix to return error code -EINVAL from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 622ec2c9d524 ("net: core: add UID to flows, rules, and routes")
Signed-off-by: Wei Yongjun 
Signed-off-by: David S. Miller

net: rtnetlink: plumb extended ack to doit function

2017-04-17T19:35:38+00:00

Add netlink_ext_ack arg to rtnl_doit_func. Pass extack arg to nlmsg_parse
for doit functions that call it directly.

This is the first step to using extended error reporting in rtnetlink.
>From here individual subsystems can be updated to set netlink_ext_ack as
needed.

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

netlink: pass extended ACK struct to parsing functions

2017-04-13T17:58:22+00:00

Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

Signed-off-by: Johannes Berg 
Signed-off-by: David S. Miller

ipv4: fib_rules: Check if rule is a default rule

2017-03-16T17:18:33+00:00

Currently, when non-default (custom) FIB rules are used, devices capable
of layer 3 offloading flush their tables and let the kernel do the
forwarding instead.

When these devices' drivers are loaded they register to the FIB
notification chain, which lets them know about the existence of any
custom FIB rules. This is done by sending a RULE_ADD notification based
on the value of 'net->ipv4.fib_has_custom_rules'.

This approach is problematic when VRF offload is taken into account, as
upon the creation of the first VRF netdev, a l3mdev rule is programmed
to direct skbs to the VRF's table.

Instead of merely reading the above value and sending a single RULE_ADD
notification, we should iterate over all the FIB rules and send a
detailed notification for each, thereby allowing offloading drivers to
sanitize the rules they don't support and potentially flush their
tables.

While l3mdev rules are uniquely marked, the default rules are not.
Therefore, when they are being notified they might invoke offloading
drivers to unnecessarily flush their tables.

Solve this by adding an helper to check if a FIB rule is a default rule.
Namely, its selector should match all packets and its action should
point to the local, main or default tables.

As noted by David Ahern, uniquely marking the default rules is
insufficient. When using VRFs, it's common to avoid false hits by moving
the rule for the local table to just before the main table:

Default configuration:
$ ip rule show
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Common configuration with VRFs:
$ ip rule show
1000:   from all lookup [l3mdev-table]
32765:  from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Signed-off-by: Ido Schimmel 
Signed-off-by: Jiri Pirko 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

net: core: add missing check for uid_range in rule_exists.

2016-11-09T18:28:10+00:00

Without this check, it is not possible to create two rules that
are identical except for their UID ranges. For example:

root@net-test:/# ip rule add prio 1000 lookup 300
root@net-test:/# ip rule add prio 1000 uidrange 100-200 lookup 300
RTNETLINK answers: File exists
root@net-test:/# ip rule add prio 1000 uidrange 100-199 lookup 100
root@net-test:/# ip rule add prio 1000 uidrange 200-299 lookup 200
root@net-test:/# ip rule add prio 1000 uidrange 300-399 lookup 100
RTNETLINK answers: File exists

Tested: https://android-review.googlesource.com/#/c/299980/
Signed-off-by: Lorenzo Colitti 
Acked-by: Maciej Żenczykowski 
Signed-off-by: David S. Miller

net: core: add UID to flows, rules, and routes

2016-11-04T18:45:23+00:00

- Define a new FIB rule attributes, FRA_UID_RANGE, to describe a
  range of UIDs.
- Define a RTA_UID attribute for per-UID route lookups and dumps.
- Support passing these attributes to and from userspace via
  rtnetlink. The value INVALID_UID indicates no UID was
  specified.
- Add a UID field to the flow structures.

Signed-off-by: Lorenzo Colitti 
Signed-off-by: David S. Miller