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Shigeru Yoshida 0297e7ddf5 af_unix: Fix uninit-value in __unix_walk_scc()
commit 927fa5b3e4 upstream.

KMSAN reported uninit-value access in __unix_walk_scc() [1].

In the list_for_each_entry_reverse() loop, when the vertex's index
equals it's scc_index, the loop uses the variable vertex as a
temporary variable that points to a vertex in scc. And when the loop
is finished, the variable vertex points to the list head, in this case
scc, which is a local variable on the stack (more precisely, it's not
even scc and might underflow the call stack of __unix_walk_scc():
container_of(&scc, struct unix_vertex, scc_entry)).

However, the variable vertex is used under the label prev_vertex. So
if the edge_stack is not empty and the function jumps to the
prev_vertex label, the function will access invalid data on the
stack. This causes the uninit-value access issue.

Fix this by introducing a new temporary variable for the loop.

[1]
BUG: KMSAN: uninit-value in __unix_walk_scc net/unix/garbage.c:478 [inline]
BUG: KMSAN: uninit-value in unix_walk_scc net/unix/garbage.c:526 [inline]
BUG: KMSAN: uninit-value in __unix_gc+0x2589/0x3c20 net/unix/garbage.c:584
 __unix_walk_scc net/unix/garbage.c:478 [inline]
 unix_walk_scc net/unix/garbage.c:526 [inline]
 __unix_gc+0x2589/0x3c20 net/unix/garbage.c:584
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xade/0x1bf0 kernel/workqueue.c:3312
 worker_thread+0xeb6/0x15b0 kernel/workqueue.c:3393
 kthread+0x3c4/0x530 kernel/kthread.c:389
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 unix_walk_scc net/unix/garbage.c:526 [inline]
 __unix_gc+0x2adf/0x3c20 net/unix/garbage.c:584
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xade/0x1bf0 kernel/workqueue.c:3312
 worker_thread+0xeb6/0x15b0 kernel/workqueue.c:3393
 kthread+0x3c4/0x530 kernel/kthread.c:389
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Local variable entries created at:
 ref_tracker_free+0x48/0xf30 lib/ref_tracker.c:222
 netdev_tracker_free include/linux/netdevice.h:4058 [inline]
 netdev_put include/linux/netdevice.h:4075 [inline]
 dev_put include/linux/netdevice.h:4101 [inline]
 update_gid_event_work_handler+0xaa/0x1b0 drivers/infiniband/core/roce_gid_mgmt.c:813

CPU: 1 PID: 12763 Comm: kworker/u8:31 Not tainted 6.10.0-rc4-00217-g35bb670d65fc #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
Workqueue: events_unbound __unix_gc

Fixes: 3484f06317 ("af_unix: Detect Strongly Connected Components.")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240702160428.10153-1-syoshida@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-06-04 14:40:25 +02:00
arch x86/mm/init: Handle the special case of device private pages in add_pages(), to not increase max_pfn and trigger dma_addressing_limited() bounce buffers bounce buffers 2025-06-04 14:40:22 +02:00
block scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer 2025-05-22 14:10:06 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2025-04-25 10:44:04 +02:00
crypto crypto: algif_hash - fix double free in hash_accept 2025-06-04 14:40:20 +02:00
Documentation serial: mctrl_gpio: split disable_ms into sync and no_sync APIs 2025-06-04 14:40:13 +02:00
drivers octeontx2-pf: Fix page pool frag allocation warning 2025-06-04 14:40:22 +02:00
fs btrfs: check folio mapping after unlock in relocate_one_folio() 2025-06-04 14:40:22 +02:00
include af_unix: Add dead flag to struct scm_fp_list. 2025-06-04 14:40:24 +02:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:47:04 +02:00
io_uring io_uring: fix overflow resched cqe reordering 2025-06-04 14:40:20 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-14 19:54:06 +01:00
kernel hrtimers: Force migrate away hrtimers queued after CPUHP_AP_HRTIMERS_DYING 2025-06-04 14:40:22 +02:00
lib crypto: lzo - Fix compression buffer overrun 2025-06-04 14:40:08 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/page_alloc.c: avoid infinite retries caused by cpuset race 2025-06-04 14:40:21 +02:00
net af_unix: Fix uninit-value in __unix_walk_scc() 2025-06-04 14:40:25 +02:00
rust scripts: generate_rust_analyzer: provide cfgs for core and alloc 2025-03-28 21:58:57 +01:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-06-04 14:40:02 +02:00
scripts kbuild: fix argument parsing in scripts/config 2025-06-04 14:40:06 +02:00
security smack: recognize ipv4 CIPSO w/o categories 2025-06-04 14:40:14 +02:00
sound ALSA: hda/realtek: Add quirk for Lenovo Yoga Pro 7 14ASP10 2025-06-04 14:40:21 +02:00
tools bpftool: Fix readlink usage in get_fd_type 2025-06-04 14:40:17 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:46:21 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 Remove *.orig pattern from .gitignore 2024-10-17 15:21:15 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -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 Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 sign-file,extract-cert: move common SSL helper functions to a header 2025-04-25 10:44:04 +02:00
Makefile kbuild: Disable -Wdefault-const-init-unsafe 2025-06-04 14:40:22 +02:00
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.