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GUO Zihua 578b565b24 9p/fd: Fix write overflow in p9_read_work
This error was reported while fuzzing:

BUG: KASAN: slab-out-of-bounds in _copy_to_iter+0xd35/0x1190
Write of size 4043 at addr ffff888008724eb1 by task kworker/1:1/24

CPU: 1 PID: 24 Comm: kworker/1:1 Not tainted 6.1.0-rc5-00002-g1adf73218daa-dirty #223
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
Workqueue: events p9_read_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x4c/0x64
 print_report+0x178/0x4b0
 kasan_report+0xae/0x130
 kasan_check_range+0x179/0x1e0
 memcpy+0x38/0x60
 _copy_to_iter+0xd35/0x1190
 copy_page_to_iter+0x1d5/0xb00
 pipe_read+0x3a1/0xd90
 __kernel_read+0x2a5/0x760
 kernel_read+0x47/0x60
 p9_read_work+0x463/0x780
 process_one_work+0x91d/0x1300
 worker_thread+0x8c/0x1210
 kthread+0x280/0x330
 ret_from_fork+0x22/0x30
 </TASK>

Allocated by task 457:
 kasan_save_stack+0x1c/0x40
 kasan_set_track+0x21/0x30
 __kasan_kmalloc+0x7e/0x90
 __kmalloc+0x59/0x140
 p9_fcall_init.isra.11+0x5d/0x1c0
 p9_tag_alloc+0x251/0x550
 p9_client_prepare_req+0x162/0x350
 p9_client_rpc+0x18d/0xa90
 p9_client_create+0x670/0x14e0
 v9fs_session_init+0x1fd/0x14f0
 v9fs_mount+0xd7/0xaf0
 legacy_get_tree+0xf3/0x1f0
 vfs_get_tree+0x86/0x2c0
 path_mount+0x885/0x1940
 do_mount+0xec/0x100
 __x64_sys_mount+0x1a0/0x1e0
 do_syscall_64+0x3a/0x90
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

This BUG pops up when trying to reproduce
https://syzkaller.appspot.com/bug?id=6c7cd46c7bdd0e86f95d26ec3153208ad186f9fa
The callstack is different but the issue is valid and re-producable with
the same re-producer in the link.

The root cause of this issue is that we check the size of the message
received against the msize of the client in p9_read_work. However, it
turns out that capacity is no longer consistent with msize. Thus,
the message size should be checked against sdata capacity.

As the msize is non-consistant with the capacity of the tag and as we
are now checking message size against capacity directly, there is no
point checking message size against msize. So remove it.

Link: https://lkml.kernel.org/r/20221117091159.31533-2-guozihua@huawei.com
Link: https://lkml.kernel.org/r/20221117091159.31533-3-guozihua@huawei.com
Reported-by: syzbot+0f89bd13eaceccc0e126@syzkaller.appspotmail.com
Fixes: 60ece0833b ("net/9p: allocate appropriate reduced message buffers")
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
[Dominique: squash patches 1 & 2 and fix size including header part]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-11-18 22:29:57 +09:00
arch - Add Cooper Lake's stepping to the PEBS guest/host events isolation 2022-11-06 12:41:32 -08:00
block block-6.1-2022-11-05 2022-11-05 09:02:28 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation Kbuild fixes for v6.1 (2nd) 2022-11-06 12:23:10 -08:00
drivers cxl fixes for 6.1-rc4 2022-11-06 13:09:52 -08:00
fs Fix a number of bug fixes, including some regressions, the most 2022-11-06 10:30:29 -08:00
include kernel hardening fix for v6.1-rc4 2022-11-04 14:46:45 -07:00
init init: Kconfig: fix spelling mistake "satify" -> "satisfy" 2022-10-20 21:27:22 -07:00
io_uring io_uring: unlock if __io_run_local_work locked inside 2022-10-27 09:52:12 -06:00
ipc ipc/msg.c: fix percpu_counter use after free 2022-10-28 13:37:22 -07:00
kernel - Add Cooper Lake's stepping to the PEBS guest/host events isolation 2022-11-06 12:41:32 -08:00
lib Networking fixes for 6.1-rc4, including fixes from bluetooth and 2022-11-03 10:51:59 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mmap: fix remap_file_pages() regression 2022-10-28 13:37:23 -07:00
net 9p/fd: Fix write overflow in p9_read_work 2022-11-18 22:29:57 +09:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts kconfig: fix segmentation fault in menuconfig search 2022-11-02 17:32:05 +09:00
security lsm/stable-6.1 PR 20221031 2022-10-31 12:09:42 -07:00
sound ALSA: aoa: Fix I2S device accounting 2022-10-27 08:53:08 +02:00
tools cxl fixes for 6.1-rc4 2022-11-06 13:09:52 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt Merge tag 'kvmarm-fixes-6.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD 2022-11-06 03:30:49 -05:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap mailmap: update email for Qais Yousef 2022-10-20 21:27:21 -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 drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
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 ARM: SoC fixes for 6.1, part 2 2022-11-04 14:13:12 -07:00
Makefile Linux 6.1-rc4 2022-11-06 15:07:11 -08:00
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.