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Jakub Kicinski 3bf39fa849 netlink: fix false positive warning in extack during dumps
Commit under fixes extended extack reporting to dumps.
It works under normal conditions, because extack errors are
usually reported during ->start() or the first ->dump(),
it's quite rare that the dump starts okay but fails later.
If the dump does fail later, however, the input skb will
already have the initiating message pulled, so checking
if bad attr falls within skb->data will fail.

Switch the check to using nlh, which is always valid.

syzbot found a way to hit that scenario by filling up
the receive queue. In this case we initiate a dump
but don't call ->dump() until there is read space for
an skb.

WARNING: CPU: 1 PID: 5845 at net/netlink/af_netlink.c:2210 netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209
RIP: 0010:netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209
Call Trace:
 <TASK>
 netlink_dump_done+0x513/0x970 net/netlink/af_netlink.c:2250
 netlink_dump+0x91f/0xe10 net/netlink/af_netlink.c:2351
 netlink_recvmsg+0x6bb/0x11d0 net/netlink/af_netlink.c:1983
 sock_recvmsg_nosec net/socket.c:1051 [inline]
 sock_recvmsg+0x22f/0x280 net/socket.c:1073
 __sys_recvfrom+0x246/0x3d0 net/socket.c:2267
 __do_sys_recvfrom net/socket.c:2285 [inline]
 __se_sys_recvfrom net/socket.c:2281 [inline]
 __x64_sys_recvfrom+0xde/0x100 net/socket.c:2281
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x7ff37dd17a79

Reported-by: syzbot+d4373fa8042c06cefa84@syzkaller.appspotmail.com
Fixes: 8af4f60472 ("netlink: support all extack types in dumps")
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20241119224432.1713040-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-24 16:58:07 -08:00
arch Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
block for-6.13/block-20241118 2024-11-18 16:50:08 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Random number generator updates for Linux 6.13-rc1. 2024-11-19 10:43:44 -08:00
Documentation Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
drivers net: microchip: vcap: Add typegroup table terminators in kunit tests 2024-11-24 16:52:13 -08:00
fs Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
include Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
init printk changes for 6.13 2024-11-20 09:21:11 -08:00
io_uring A rather large update for timekeeping and timers: 2024-11-19 16:35:06 -08:00
ipc fdget(), more trivial conversions 2024-11-03 01:28:06 -05:00
kernel Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
lib Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
net netlink: fix false positive warning in extack during dumps 2024-11-24 16:58:07 -08:00
rust Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
samples bpf-next-bpf-next-6.13 2024-11-21 08:11:04 -08:00
scripts bpf-next-bpf-next-6.13 2024-11-21 08:11:04 -08:00
security This update includes the following changes: 2024-11-19 10:28:41 -08:00
sound Devicetree updates for v6.13: 2024-11-20 13:19:25 -08:00
tools selftests: fix nested double quotes in f-string 2024-11-24 16:42:44 -08:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt the bulk of struct fd memory safety stuff 2024-11-18 12:24:06 -08:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +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: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap media updates for v6.13-rc1 2024-11-20 14:01:15 -08:00
.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 cgroup: Changes for v6.13 2024-11-20 09:54:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking changes for 6.13. 2024-11-21 08:28:08 -08:00
Makefile Linux 6.12 2024-11-17 14:15:08 -08:00
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.