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Wen Yang d31563b5f9 eventfd: strictly check the count parameter of eventfd_write to avoid inputting illegal strings
Since eventfd's document has clearly stated: A write(2) call adds
the 8-byte integer value supplied in its buffer to the counter.

However, in the current implementation, the following code snippet
did not cause an error:

	char str[16] = "hello world";
	uint64_t value;
	ssize_t size;
	int fd;

	fd = eventfd(0, 0);
	size = write(fd, &str, strlen(str));
	printf("eventfd: test writing a string, size=%ld\n", size);
	size = read(fd, &value, sizeof(value));
	printf("eventfd: test reading as uint64, size=%ld, valus=0x%lX\n",
	       size, value);

	close(fd);

And its output is:
eventfd: test writing a string, size=8
eventfd: test reading as uint64, size=8, valus=0x6F77206F6C6C6568

By checking whether count is equal to sizeof(ucnt), such errors
could be detected. It also follows the requirements of the manual.

Signed-off-by: Wen Yang <wenyang.linux@foxmail.com>
Link: https://lore.kernel.org/r/tencent_10AAA44731FFFA493F9F5501521F07DD4D0A@qq.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Eric Biggers <ebiggers@google.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-08 10:12:26 +01:00
Documentation fs: remove the inode argument to ->d_real() method 2024-02-06 17:00:12 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch powerpc fixes for 6.8 #2 2024-01-21 11:04:29 -08:00
block for-6.8/block-2024-01-18 2024-01-18 18:22:40 -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 2023-12-29 11:25:56 +08:00
drivers Updates for time and clocksources: 2024-01-21 11:14:40 -08:00
fs eventfd: strictly check the count parameter of eventfd_write to avoid inputting illegal strings 2024-02-08 10:12:26 +01:00
include fs: remove the inode argument to ->d_real() method 2024-02-06 17:00:12 +01:00
init initramfs: remove duplicate built-in __initramfs_start unpacking 2024-01-22 15:33:36 +01:00
io_uring for-6.8/io_uring-2024-01-18 2024-01-18 18:17:57 -08:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel Updates for time and clocksources: 2024-01-21 11:14:40 -08:00
lib iov_iter: Avoid wrap-around instrumentation in copy_compat_iovec_from_user() 2024-02-02 13:11:49 +01:00
mm Revert "mm/filemap: avoid buffered read/write race to read inconsistent data" 2024-01-25 17:23:51 +01:00
net Assorted CephFS fixes and cleanups with nothing standing out. 2024-01-19 09:58:55 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples RISC-V Patches for the 6.8 Merge Window, Part 4 2024-01-20 11:06:04 -08:00
scripts Coccinelle change for v6.8 2024-01-20 14:20:34 -08:00
security + Features 2024-01-19 10:53:55 -08:00
sound sound fixes for 6.8-rc1 2024-01-19 12:30:29 -08:00
tools selftests/move_mount_set_group:Make tests build with old libc 2024-01-22 15:33:37 +01:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's `for_each` macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.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 Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -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 Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -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 Various smb client fixes, including multichannel and for SMB3.1.1 POSIX extensions 2024-01-20 16:48:07 -08:00
Makefile Linux 6.8-rc1 2024-01-21 14:11:32 -08:00
README

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.