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Ilya Maximets c999153bfb net: openvswitch: fix middle attribute validation in push_nsh() action
[ Upstream commit 5ace7ef87f ]

The push_nsh() action structure looks like this:

 OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...))

The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the
nla_for_each_nested() inside __ovs_nla_copy_actions().  The innermost
OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested()
inside nsh_key_put_from_nlattr().  But nothing checks if the attribute
in the middle is OK.  We don't even check that this attribute is the
OVS_KEY_ATTR_NSH.  We just do a double unwrap with a pair of nla_data()
calls - first time directly while calling validate_push_nsh() and the
second time as part of the nla_for_each_nested() macro, which isn't
safe, potentially causing invalid memory access if the size of this
attribute is incorrect.  The failure may not be noticed during
validation due to larger netlink buffer, but cause trouble later during
action execution where the buffer is allocated exactly to the size:

 BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
 Read of size 184 at addr ffff88816459a634 by task a.out/22624

 CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary)
 Call Trace:
  <TASK>
  dump_stack_lvl+0x51/0x70
  print_address_description.constprop.0+0x2c/0x390
  kasan_report+0xdd/0x110
  kasan_check_range+0x35/0x1b0
  __asan_memcpy+0x20/0x60
  nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
  push_nsh+0x82/0x120 [openvswitch]
  do_execute_actions+0x1405/0x2840 [openvswitch]
  ovs_execute_actions+0xd5/0x3b0 [openvswitch]
  ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch]
  genl_family_rcv_msg_doit+0x1d6/0x2b0
  genl_family_rcv_msg+0x336/0x580
  genl_rcv_msg+0x9f/0x130
  netlink_rcv_skb+0x11f/0x370
  genl_rcv+0x24/0x40
  netlink_unicast+0x73e/0xaa0
  netlink_sendmsg+0x744/0xbf0
  __sys_sendto+0x3d6/0x450
  do_syscall_64+0x79/0x2c0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  </TASK>

Let's add some checks that the attribute is properly sized and it's
the only one attribute inside the action.  Technically, there is no
real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're
pushing an NSH header already, it just creates extra nesting, but
that's how uAPI works today.  So, keeping as it is.

Fixes: b2d0f5d5dc ("openvswitch: enable NSH support")
Reported-by: Junvy Yang <zhuque@tencent.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Eelco Chaudron echaudro@redhat.com
Reviewed-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/20251204105334.900379-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-01-02 12:56:45 +01:00
arch x86/microcode: Mark early_parse_cmdline() as __init 2026-01-02 12:56:39 +01:00
block block: Use RCU in blk_mq_[un]quiesce_tagset() instead of set->tag_list_lock 2025-12-18 14:03:40 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ahash - Zero positive err value in ahash_update_finish 2025-12-18 14:03:12 +01:00
Documentation docs: hwmon: fix link to g762 devicetree binding 2025-12-18 14:03:38 +01:00
drivers bnxt_en: Fix XDP_TX path 2026-01-02 12:56:45 +01:00
fs gfs2: Fix use of bio_chain 2026-01-02 12:56:43 +01:00
include shmem: fix recovery on rename failures 2026-01-02 12:56:37 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/kbuf: use READ_ONCE() for userspace-mapped memory 2025-12-18 14:03:36 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel livepatch: Match old_sympos 0 and 1 in klp_find_func() 2026-01-02 12:56:39 +01:00
lib lib/vsprintf: Check pointer before dereferencing in time_and_date() 2025-12-18 14:02:58 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm shmem: fix recovery on rename failures 2026-01-02 12:56:37 +01:00
net net: openvswitch: fix middle attribute validation in push_nsh() action 2026-01-02 12:56:45 +01:00
rust rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags 2025-11-10 08:37:06 +08:00
samples samples: work around glibc redefining some of our defines wrong 2025-11-21 09:29:02 -08:00
scripts kbuild: Use objtree for module signing key path 2026-01-02 12:56:40 +01:00
security landlock: Fix handling of disconnected directories 2025-12-18 14:03:27 +01:00
sound ALSA: wavefront: Fix integer overflow in sample size validation 2025-12-18 14:03:43 +01:00
tools perf stat: Allow no events to open if this is a "--null" run 2025-12-18 14:03:32 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.2 2025-12-18 14:03:43 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.