linux-stable.git/net/openvswitch/meter.c, branch v7.2

net: openvswitch: fix potential UAF on meter attach failure

2026-07-30T11:20:03+00:00

While attaching a newly created meter attach_meter() function makes
the new meter visible to other CPUs but can still fail afterwards.
On failure, it detaches the meter back and returns an error.

However, this is an unexpected behavior for the ovs_meter_cmd_set()
that uses a plain kfree(meter) on attach failure without waiting for
RCU readers to stop using it, assuming it was never visible.

This is never a problem for ovs-vswitchd as it always creates meters
before creating any flows that use them.  But the UAF can be triggered
with a custom application using uAPI:

 BUG: KASAN: slab-use-after-free in ovs_meter_execute (net/openvswitch/meter.c:653)
 Read of size 8 at addr ffff88810d152650 by task meter/2508

 Call Trace:
  ovs_meter_execute (net/openvswitch/meter.c:653)
  do_execute_actions (net/openvswitch/actions.c:1407)
  ovs_execute_actions (net/openvswitch/actions.c:1584)
  ovs_packet_cmd_execute (net/openvswitch/datapath.c:703)
  ...
  netlink_sendmsg (af_netlink.c:1900)

 Allocated by task 2519:
  __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
  ovs_meter_cmd_set (net/openvswitch/meter.c:422)
  ...
  netlink_sendmsg (af_netlink.c:1900)

 Freed by task 2519:
  kfree (mm/slub.c:2705 mm/slub.c:6405 mm/slub.c:6720)
  ovs_meter_cmd_set (net/openvswitch/meter.c:479)
  ...
  netlink_sendmsg (af_netlink.c:1900)

Fix that by making sure attach_meter() doesn't make the meter visible
until all the checks are done and the function can't fail anymore.

This also makes sure the "hash" value is calculated after the potential
re-sizing of the table.

Reported by Trend Micro's Zero Day Initiative as ZDI-CAN-31642.

Fixes: c7c4c44c9a95 ("net: openvswitch: expand the meters supported number")
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Maximets 
Reviewed-by: Eelco Chaudron 
Link: https://patch.msgid.link/20260727121022.198461-1-i.maximets@ovn.org
Signed-off-by: Paolo Abeni

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.

As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.

Signed-off-by: Linus Torvalds

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook

genetlink: remove userhdr from struct genl_info

2023-08-15T21:54:44+00:00

Only three families use info->userhdr today and going forward
we discourage using fixed headers in new families.
So having the pointer to user header in struct genl_info
is an overkill. Compute the header pointer at runtime.

Reviewed-by: Johannes Berg 
Reviewed-by: Jiri Pirko 
Reviewed-by: Aaron Conole 
Link: https://lore.kernel.org/r/20230814214723.2924989-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: openvswitch: Use struct_size()

2023-05-18T04:25:46+00:00

Use struct_size() instead of hand writing it.
This is less verbose and more informative.

Signed-off-by: Christophe JAILLET 
Acked-by: Eelco Chaudron 
Link: https://lore.kernel.org/r/e7746fbbd62371d286081d5266e88bbe8d3fe9f0.1683388991.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski

net: openvswitch: fix possible memory leak in ovs_meter_cmd_set()

2023-02-13T09:38:25+00:00

old_meter needs to be free after it is detached regardless of whether
the new meter is successfully attached.

Fixes: c7c4c44c9a95 ("net: openvswitch: expand the meters supported number")
Signed-off-by: Hangyu Hua 
Acked-by: Eelco Chaudron 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller

net: openvswitch: allow metering in non-initial user namespace

2022-09-27T09:31:36+00:00

The Netlink interface for metering was restricted to global CAP_NET_ADMIN
by using GENL_ADMIN_PERM. To allow metring in a non-inital user namespace,
e.g., a container, this is changed to GENL_UNS_ADMIN_PERM.

Signed-off-by: Michael Weiß 
Signed-off-by: Paolo Abeni

genetlink: start to validate reserved header bytes

2022-08-29T11:47:15+00:00

We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski 
Acked-by: Paul Moore  (NetLabel)
Signed-off-by: David S. Miller

include/linux/mm.h: move nr_free_buffer_pages from swap.h to mm.h

2021-11-06T20:30:43+00:00

nr_free_buffer_pages could be exposed through mm.h instead of swap.h.
The advantage of this change is that it can reduce the obsolete
includes.  For example, net/ipv4/tcp.c wouldn't need swap.h any more
since it has already included mm.h.  Similarly, after checking all the
other files, it comes that tcp.c, udp.c meter.c ,...  follow the same
rule, so these files can have swap.h removed too.

Moreover, after preprocessing all the files that use
nr_free_buffer_pages, it turns out that those files have already
included mm.h.Thus, we can move nr_free_buffer_pages from swap.h to mm.h
safely.  This change will not affect the compilation of other files.

Link: https://lkml.kernel.org/r/20210912133640.1624-1-liumh1@shanghaitech.edu.cn
Signed-off-by: Mianhan Liu 
Cc: Jakub Kicinski 
CC: Ulf Hansson 
Cc: "David S . Miller" 
Cc: Simon Horman 
Cc: Pravin B Shelar 
Cc: Vlad Yasevich 
Cc: Marcelo Ricardo Leitner 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

openvswitch: meter: fix race when getting now_ms.

2021-05-13T22:54:59+00:00

We have observed meters working unexpected if traffic is 3+Gbit/s
with multiple connections.

now_ms is not pretected by meter->lock, we may get a negative
long_delta_ms when another cpu updated meter->used, then:
    delta_ms = (u32)long_delta_ms;
which will be a large value.

    band->bucket += delta_ms * band->rate;
then we get a wrong band->bucket.

OpenVswitch userspace datapath has fixed the same issue[1] some
time ago, and we port the implementation to kernel datapath.

[1] https://patchwork.ozlabs.org/project/openvswitch/patch/20191025114436.9746-1-i.maximets@ovn.org/

Fixes: 96fbc13d7e77 ("openvswitch: Add meter infrastructure")
Signed-off-by: Tao Liu 
Suggested-by: Ilya Maximets 
Reviewed-by: Ilya Maximets 
Signed-off-by: David S. Miller