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Peter Delevoryas 87ac26716a net/ncsi: Fix netlink major/minor version numbers
[ Upstream commit 3084b58bfd ]

The netlink interface for major and minor version numbers doesn't actually
return the major and minor version numbers.

It reports a u32 that contains the (major, minor, update, alpha1)
components as the major version number, and then alpha2 as the minor
version number.

For whatever reason, the u32 byte order was reversed (ntohl): maybe it was
assumed that the encoded value was a single big-endian u32, and alpha2 was
the minor version.

The correct way to get the supported NC-SI version from the network
controller is to parse the Get Version ID response as described in 8.4.44
of the NC-SI spec[1].

    Get Version ID Response Packet Format

              Bits
            +--------+--------+--------+--------+
     Bytes  | 31..24 | 23..16 | 15..8  | 7..0   |
    +-------+--------+--------+--------+--------+
    | 0..15 | NC-SI Header                      |
    +-------+--------+--------+--------+--------+
    | 16..19| Response code   | Reason code     |
    +-------+--------+--------+--------+--------+
    |20..23 | Major  | Minor  | Update | Alpha1 |
    +-------+--------+--------+--------+--------+
    |24..27 |         reserved         | Alpha2 |
    +-------+--------+--------+--------+--------+
    |            .... other stuff ....          |

The major, minor, and update fields are all binary-coded decimal (BCD)
encoded [2]. The spec provides examples below the Get Version ID response
format in section 8.4.44.1, but for practical purposes, this is an example
from a live network card:

    root@bmc:~# ncsi-util 0x15
    NC-SI Command Response:
    cmd: GET_VERSION_ID(0x15)
    Response: COMMAND_COMPLETED(0x0000)  Reason: NO_ERROR(0x0000)
    Payload length = 40

    20: 0xf1 0xf1 0xf0 0x00 <<<<<<<<< (major, minor, update, alpha1)
    24: 0x00 0x00 0x00 0x00 <<<<<<<<< (_, _, _, alpha2)

    28: 0x6d 0x6c 0x78 0x30
    32: 0x2e 0x31 0x00 0x00
    36: 0x00 0x00 0x00 0x00
    40: 0x16 0x1d 0x07 0xd2
    44: 0x10 0x1d 0x15 0xb3
    48: 0x00 0x17 0x15 0xb3
    52: 0x00 0x00 0x81 0x19

This should be parsed as "1.1.0".

"f" in the upper-nibble means to ignore it, contributing zero.

If both nibbles are "f", I think the whole field is supposed to be ignored.
Major and minor are "required", meaning they're not supposed to be "ff",
but the update field is "optional" so I think it can be ff. I think the
simplest thing to do is just set the major and minor to zero instead of
juggling some conditional logic or something.

bcd2bin() from "include/linux/bcd.h" seems to assume both nibbles are 0-9,
so I've provided a custom BCD decoding function.

Alpha1 and alpha2 are ISO/IEC 8859-1 encoded, which just means ASCII
characters as far as I can tell, although the full encoding table for
non-alphabetic characters is slightly different (I think).

I imagine the alpha fields are just supposed to be alphabetic characters,
but I haven't seen any network cards actually report a non-zero value for
either.

If people wrote software against this netlink behavior, and were parsing
the major and minor versions themselves from the u32, then this would
definitely break their code.

[1] https://www.dmtf.org/sites/default/files/standards/documents/DSP0222_1.0.0.pdf
[2] https://en.wikipedia.org/wiki/Binary-coded_decimal
[2] https://en.wikipedia.org/wiki/ISO/IEC_8859-1

Signed-off-by: Peter Delevoryas <peter@pjd.dev>
Fixes: 138635cc27 ("net/ncsi: NCSI response packet handler")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-01-25 15:44:45 -08:00
arch ARM: dts: qcom: apq8064: correct XOADC register address 2024-01-25 15:44:45 -08:00
block block-6.7-2023-12-29 2023-12-29 11:41:40 -08:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: scomp - fix req->dst buffer overflow 2024-01-25 15:44:43 -08:00
Documentation docs: kernel_feat.py: fix potential command injection 2024-01-20 11:53:02 +01:00
drivers scsi: lpfc: Fix list_entry null check warning in lpfc_cmpl_els_plogi() 2024-01-25 15:44:45 -08:00
fs pNFS: Fix the pnfs block driver's calculation of layoutget size 2024-01-25 15:44:44 -08:00
include bpf: Add crosstask check to __bpf_get_stack 2024-01-25 15:44:45 -08:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring/cmd: fix breakage in SOCKET_URING_OP_SIOC* implementation 2023-12-14 16:52:13 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel bpf: Add crosstask check to __bpf_get_stack 2024-01-25 15:44:45 -08:00
lib kunit: debugfs: Handle errors from alloc_string_stream() 2024-01-25 15:44:40 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/memory_hotplug: fix memmap_on_memory sysfs value retrieval 2024-01-20 11:53:02 +01:00
net net/ncsi: Fix netlink major/minor version numbers 2024-01-25 15:44:45 -08:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts scripts/decode_stacktrace.sh: optionally use LLVM utilities 2024-01-20 11:53:02 +01:00
security selinux: Fix error priority for bind with AF_UNSPEC on PF_INET6 socket 2024-01-25 15:44:40 -08:00
sound ALSA: hda: cs35l41: Support more HP models without _DSD 2024-01-20 11:53:00 +01:00
tools bpf: Add crosstask check to __bpf_get_stack 2024-01-25 15:44:45 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt KVM/arm64 fixes for 6.7, part #2 2023-12-22 18:03:54 -05:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -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 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -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 12 hotfixes. 2 are cc:stable and the remainder either address post-6.7 2024-01-05 13:46:18 -08:00
Makefile Linux 6.7.1 2024-01-20 11:53:02 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 Restructured Text 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.