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Justin Stitt efb905aeb4 cdrom: rearrange last_media_change check to avoid unintentional overflow
When running syzkaller with the newly reintroduced signed integer wrap
sanitizer we encounter this splat:

[  366.015950] UBSAN: signed-integer-overflow in ../drivers/cdrom/cdrom.c:2361:33
[  366.021089] -9223372036854775808 - 346321 cannot be represented in type '__s64' (aka 'long long')
[  366.025894] program syz-executor.4 is using a deprecated SCSI ioctl, please convert it to SG_IO
[  366.027502] CPU: 5 PID: 28472 Comm: syz-executor.7 Not tainted 6.8.0-rc2-00035-gb3ef86b5a957 #1
[  366.027512] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[  366.027518] Call Trace:
[  366.027523]  <TASK>
[  366.027533]  dump_stack_lvl+0x93/0xd0
[  366.027899]  handle_overflow+0x171/0x1b0
[  366.038787] ata1.00: invalid multi_count 32 ignored
[  366.043924]  cdrom_ioctl+0x2c3f/0x2d10
[  366.063932]  ? __pm_runtime_resume+0xe6/0x130
[  366.071923]  sr_block_ioctl+0x15d/0x1d0
[  366.074624]  ? __pfx_sr_block_ioctl+0x10/0x10
[  366.077642]  blkdev_ioctl+0x419/0x500
[  366.080231]  ? __pfx_blkdev_ioctl+0x10/0x10
...

Historically, the signed integer overflow sanitizer did not work in the
kernel due to its interaction with `-fwrapv` but this has since been
changed [1] in the newest version of Clang. It was re-enabled in the
kernel with Commit 557f8c582a ("ubsan: Reintroduce signed overflow
sanitizer").

Let's rearrange the check to not perform any arithmetic, thus not
tripping the sanitizer.

Link: https://github.com/llvm/llvm-project/pull/82432 [1]
Closes: https://github.com/KSPP/linux/issues/354
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/lkml/20240507-b4-sio-ata1-v1-1-810ffac6080a@google.com
Reviewed-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/lkml/ZjqU0fbzHrlnad8D@equinox
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20240507222520.1445-2-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-15 12:59:55 -06:00
arch This update includes the following changes: 2024-05-13 14:53:05 -07:00
block for-6.10/block-20240511 2024-05-13 13:03:54 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This update includes the following changes: 2024-05-13 14:53:05 -07:00
Documentation Rust changes for v6.10 2024-05-13 15:13:54 -07:00
drivers cdrom: rearrange last_media_change check to avoid unintentional overflow 2024-05-15 12:59:55 -06:00
fs hardening updates for 6.10-rc1 2024-05-13 14:14:05 -07:00
include nbd: Use NULL to represent a pointer 2024-05-14 07:22:35 -06:00
init hardening updates for 6.10-rc1 2024-05-13 14:14:05 -07:00
io_uring for-6.10/io_uring-20240511 2024-05-13 12:48:06 -07:00
ipc fs: Add FOP_HUGE_PAGES 2024-04-09 10:53:44 +02:00
kernel This update includes the following changes: 2024-05-13 14:53:05 -07:00
lib hardening updates for 6.10-rc1 2024-05-13 14:14:05 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm for-6.10/io_uring-20240511 2024-05-13 12:48:06 -07:00
net for-6.10/io_uring-20240511 2024-05-13 12:48:06 -07:00
rust Rust changes for v6.10 2024-05-13 15:13:54 -07:00
samples rust: sync: update Arc and UniqueArc to take allocation flags 2024-04-16 22:50:04 +02:00
scripts Rust changes for v6.10 2024-05-13 15:13:54 -07:00
security Hi 2024-05-13 10:48:35 -07:00
sound ALSA: hda/realtek: Fix build error without CONFIG_PM 2024-05-02 08:25:06 +02:00
tools vfs-6.10.misc 2024-05-13 11:40:06 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start() 2024-04-11 12:58:53 -07:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap Another not-too-busy cycle for documentation, including: 2024-05-13 10:51:53 -07:00
.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: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
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 This update includes the following changes: 2024-05-13 14:53:05 -07:00
Makefile Linux 6.9 2024-05-12 14:12:29 -07:00
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.