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Hawkins Jiawei b334ab4c33 wifi: wext: use flex array destination for memcpy()
commit e3e6e1d16a upstream.

Syzkaller reports buffer overflow false positive as follows:
------------[ cut here ]------------
memcpy: detected field-spanning write (size 8) of single field
	"&compat_event->pointer" at net/wireless/wext-core.c:623 (size 4)
WARNING: CPU: 0 PID: 3607 at net/wireless/wext-core.c:623
	wireless_send_event+0xab5/0xca0 net/wireless/wext-core.c:623
Modules linked in:
CPU: 1 PID: 3607 Comm: syz-executor659 Not tainted
	6.0.0-rc6-next-20220921-syzkaller #0
[...]
Call Trace:
 <TASK>
 ioctl_standard_call+0x155/0x1f0 net/wireless/wext-core.c:1022
 wireless_process_ioctl+0xc8/0x4c0 net/wireless/wext-core.c:955
 wext_ioctl_dispatch net/wireless/wext-core.c:988 [inline]
 wext_ioctl_dispatch net/wireless/wext-core.c:976 [inline]
 wext_handle_ioctl+0x26b/0x280 net/wireless/wext-core.c:1049
 sock_ioctl+0x285/0x640 net/socket.c:1220
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
 [...]
 </TASK>

Wireless events will be sent on the appropriate channels in
wireless_send_event(). Different wireless events may have different
payload structure and size, so kernel uses **len** and **cmd** field
in struct __compat_iw_event as wireless event common LCP part, uses
**pointer** as a label to mark the position of remaining different part.

Yet the problem is that, **pointer** is a compat_caddr_t type, which may
be smaller than the relative structure at the same position. So during
wireless_send_event() tries to parse the wireless events payload, it may
trigger the memcpy() run-time destination buffer bounds checking when the
relative structure's data is copied to the position marked by **pointer**.

This patch solves it by introducing flexible-array field **ptr_bytes**,
to mark the position of the wireless events remaining part next to
LCP part. What's more, this patch also adds **ptr_len** variable in
wireless_send_event() to improve its maintainability.

Reported-and-tested-by: syzbot+473754e5af963cf014cf@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/00000000000070db2005e95a5984@google.com/
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-26 09:24:51 +01:00
Documentation docs: update mediator contact information in CoC doc 2022-11-26 09:24:48 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch perf/x86/intel/pt: Fix sampling using single range output 2022-11-26 09:24:48 +01:00
block block: sed-opal: kmalloc the cmd/resp buffers 2022-11-26 09:24:35 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: akcipher - default implementation for setting a private key 2022-10-26 12:35:25 +02:00
drivers macvlan: enforce a consistent minimal mtu 2022-11-26 09:24:50 +01:00
fs gfs2: Switch from strlcpy to strscpy 2022-11-26 09:24:51 +01:00
include wifi: wext: use flex array destination for memcpy() 2022-11-26 09:24:51 +01:00
init stack: Declare {randomize_,}kstack_offset to fix Sparse warnings 2022-08-17 14:23:10 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:23:10 +02:00
kernel kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case 2022-11-26 09:24:50 +01:00
lib lib/Kconfig.debug: Add check for non-constant .{s,u}leb128 support to DWARF5 2022-10-26 12:35:55 +02:00
mm maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault() 2022-11-26 09:24:47 +01:00
net wifi: wext: use flex array destination for memcpy() 2022-11-26 09:24:51 +01:00
samples samples/landlock: Format with clang-format 2022-06-09 10:23:23 +02:00
scripts cert host tools: Stop complaining about deprecated OpenSSL functions 2022-11-16 09:58:28 +01:00
security capabilities: fix potential memleak on error path from vfs_getxattr_alloc() 2022-11-10 18:15:39 +01:00
sound ALSA: hda/realtek: Fix the speaker output on Samsung Galaxy Book Pro 360 2022-11-26 09:24:44 +01:00
tools selftests/intel_pstate: fix build for ARCH=x86_64 2022-11-26 09:24:30 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt kvm: Add support for arch compat vm ioctls 2022-10-29 10:12:54 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Input: goodix - add a goodix.h header file 2022-07-12 16:34:51 +02:00
Makefile Linux 5.15.79 2022-11-16 09:58:31 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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.