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Yu Kuai e2a9f73ee4 md: fix mddev uaf while iterating all_mddevs list
commit 8542870237 upstream.

While iterating all_mddevs list from md_notify_reboot() and md_exit(),
list_for_each_entry_safe is used, and this can race with deletint the
next mddev, causing UAF:

t1:
spin_lock
//list_for_each_entry_safe(mddev, n, ...)
 mddev_get(mddev1)
 // assume mddev2 is the next entry
 spin_unlock
            t2:
            //remove mddev2
            ...
            mddev_free
            spin_lock
            list_del
            spin_unlock
            kfree(mddev2)
 mddev_put(mddev1)
 spin_lock
 //continue dereference mddev2->all_mddevs

The old helper for_each_mddev() actually grab the reference of mddev2
while holding the lock, to prevent from being freed. This problem can be
fixed the same way, however, the code will be complex.

Hence switch to use list_for_each_entry, in this case mddev_put() can free
the mddev1 and it's not safe as well. Refer to md_seq_show(), also factor
out a helper mddev_put_locked() to fix this problem.

Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-raid/20250220124348.845222-1-yukuai1@huaweicloud.com
Fixes: f265143422 ("md: stop using for_each_mddev in md_notify_reboot")
Fixes: 16648bac86 ("md: stop using for_each_mddev in md_exit")
Reported-and-tested-by: Guillaume Morin <guillaume@morinfr.org>
Closes: https://lore.kernel.org/all/Z7Y0SURoA8xwg7vn@bender.morinfr.org/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-04-25 10:48:04 +02:00
arch arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9 2025-04-25 10:48:04 +02:00
block block: integrity: Do not call set_page_dirty_lock() 2025-04-25 10:47:50 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix larval relookup type and mask 2025-04-10 14:39:20 +02:00
Documentation platform/x86: msi-wmi-platform: Workaround a ACPI firmware bug 2025-04-25 10:48:04 +02:00
drivers md: fix mddev uaf while iterating all_mddevs list 2025-04-25 10:48:04 +02:00
fs virtiofs: add filesystem context source name check 2025-04-25 10:47:55 +02:00
include nfs: add missing selections of CONFIG_CRC32 2025-04-25 10:47:50 +02:00
init ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE 2025-04-10 14:39:40 +02:00
io_uring io_uring/kbuf: reject zero sized provided buffers 2025-04-20 10:15:40 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel tracing: Fix filter string testing 2025-04-25 10:47:55 +02:00
lib string: Add load_unaligned_zeropad() code path to sized_strscpy() 2025-04-25 10:47:55 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm slab: ensure slab->obj_exts is clear in a newly allocated slab page 2025-04-25 10:47:55 +02:00
net Bluetooth: l2cap: Process valid commands in too long frame 2025-04-25 10:47:51 +02:00
rust rust: Fix enabling Rust and building with GCC for LoongArch 2025-04-10 14:39:36 +02:00
samples rust: treewide: switch to the kernel Vec type 2025-03-13 13:01:46 +01:00
scripts scripts: generate_rust_analyzer: Add ffi crate 2025-04-25 10:48:04 +02:00
security landlock: Prepare to add second errata 2025-04-20 10:15:56 +02:00
sound ASoC: qcom: Fix sc7280 lpass potential buffer overflow 2025-04-25 10:47:50 +02:00
tools selftests/mm: generate a temporary mountpoint for cgroup filesystem 2025-04-25 10:47:54 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow building irqbypass.ko as as module when kvm.ko is a module 2025-04-20 10:15:54 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2025-03-13 13:01:42 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.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 rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -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 MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -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 MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile kbuild: Add '-fno-builtin-wcslen' 2025-04-25 10:48:04 +02:00
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.