linux/net/atm
Eric Dumazet d13a3824bf net: atm: add lec_mutex
syzbot found its way in net/atm/lec.c, and found an error path
in lecd_attach() could leave a dangling pointer in dev_lec[].

Add a mutex to protect dev_lecp[] uses from lecd_attach(),
lec_vcc_attach() and lec_mcast_attach().

Following patch will use this mutex for /proc/net/atm/lec.

BUG: KASAN: slab-use-after-free in lecd_attach net/atm/lec.c:751 [inline]
BUG: KASAN: slab-use-after-free in lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008
Read of size 8 at addr ffff88807c7b8e68 by task syz.1.17/6142

CPU: 1 UID: 0 PID: 6142 Comm: syz.1.17 Not tainted 6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:408 [inline]
  print_report+0xcd/0x680 mm/kasan/report.c:521
  kasan_report+0xe0/0x110 mm/kasan/report.c:634
  lecd_attach net/atm/lec.c:751 [inline]
  lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 </TASK>

Allocated by task 6132:
  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
  poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
  __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
  kasan_kmalloc include/linux/kasan.h:260 [inline]
  __do_kmalloc_node mm/slub.c:4328 [inline]
  __kvmalloc_node_noprof+0x27b/0x620 mm/slub.c:5015
  alloc_netdev_mqs+0xd2/0x1570 net/core/dev.c:11711
  lecd_attach net/atm/lec.c:737 [inline]
  lane_ioctl+0x17db/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6132:
  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
  kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
  poison_slab_object mm/kasan/common.c:247 [inline]
  __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
  kasan_slab_free include/linux/kasan.h:233 [inline]
  slab_free_hook mm/slub.c:2381 [inline]
  slab_free mm/slub.c:4643 [inline]
  kfree+0x2b4/0x4d0 mm/slub.c:4842
  free_netdev+0x6c5/0x910 net/core/dev.c:11892
  lecd_attach net/atm/lec.c:744 [inline]
  lane_ioctl+0x1ce8/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+8b64dec3affaed7b3af5@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6852c6f6.050a0220.216029.0018.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250618140844.1686882-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-19 08:36:13 -07:00
..
addr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
addr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atm_misc.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atm_sysfs.c net: atm: Remove redundant check. 2023-10-23 08:45:25 +01:00
br2684.c net: atm: use address setting helpers 2021-10-24 13:59:45 +01:00
clip.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
common.c atm: Revert atm_account_tx() if copy_from_iter_full() fails. 2025-06-17 18:42:44 -07:00
common.h net: pass a sockptr_t into ->setsockopt 2020-07-24 15:41:54 -07:00
ioctl.c atm: clean up a put_user() calls 2024-06-14 19:08:50 -07:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
lec.c net: atm: add lec_mutex 2025-06-19 08:36:13 -07:00
lec.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lec_arpc.h net: atm: lec_arpc.h: delete duplicated word 2020-07-19 18:14:21 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mpc.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
mpc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mpoa_caches.c mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
mpoa_caches.h atm: mpoa: remove 32-bit timekeeping 2017-11-30 09:26:32 -05:00
mpoa_proc.c net/atm: fix proc_mpc_write incorrect return value 2022-10-15 11:08:36 +01:00
pppoatm.c net: atm: pppoatm: use new API for wakeup tasklet 2021-01-29 18:24:05 -08:00
proc.c proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
protocols.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pvc.c sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
raw.c atm: Revert atm_account_tx() if copy_from_iter_full() fails. 2025-06-17 18:42:44 -07:00
resources.c atm: hide unused procfs functions 2023-05-17 21:27:30 -07:00
resources.h atm: lift copyin from atm_dev_ioctl() 2020-05-20 20:31:35 -04:00
signaling.c net: annotate lockless accesses to sk->sk_err_soft 2023-03-17 08:25:05 +00:00
signaling.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
svc.c net: change proto and proto_ops accept type 2024-05-13 18:19:09 -06:00