superrob1500
/
mirror-linux
mirror of https://github.com/torvalds/linux
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
mirror-linux/drivers/atm
History
Kuniyuki Iwashima ec79003c5f atm: atmtcp: Prevent arbitrary write in atmtcp_recv_control(). 
syzbot reported the splat below. [0]

When atmtcp_v_open() or atmtcp_v_close() is called via connect()
or close(), atmtcp_send_control() is called to send an in-kernel
special message.

The message has ATMTCP_HDR_MAGIC in atmtcp_control.hdr.length.
Also, a pointer of struct atm_vcc is set to atmtcp_control.vcc.

The notable thing is struct atmtcp_control is uAPI but has a
space for an in-kernel pointer.

  struct atmtcp_control {
  	struct atmtcp_hdr hdr;	/* must be first */
  ...
  	atm_kptr_t vcc;		/* both directions */
  ...
  } __ATM_API_ALIGN;

  typedef struct { unsigned char _[8]; } __ATM_API_ALIGN atm_kptr_t;

The special message is processed in atmtcp_recv_control() called
from atmtcp_c_send().

atmtcp_c_send() is vcc->dev->ops->send() and called from 2 paths:

  1. .ndo_start_xmit() (vcc->send() == atm_send_aal0())
  2. vcc_sendmsg()

The problem is sendmsg() does not validate the message length and
userspace can abuse atmtcp_recv_control() to overwrite any kptr
by atmtcp_control.

Let's add a new ->pre_send() hook to validate messages from sendmsg().

[0]:
Oops: general protection fault, probably for non-canonical address 0xdffffc00200000ab: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000100000558-0x000000010000055f]
CPU: 0 UID: 0 PID: 5865 Comm: syz-executor331 Not tainted 6.17.0-rc1-syzkaller-00215-gbab3ce404553 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:atmtcp_recv_control drivers/atm/atmtcp.c:93 [inline]
RIP: 0010:atmtcp_c_send+0x1da/0x950 drivers/atm/atmtcp.c:297
Code: 4d 8d 75 1a 4c 89 f0 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 15 06 00 00 41 0f b7 1e 4d 8d b7 60 05 00 00 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 13 06 00 00 66 41 89 1e 4d 8d 75 1c 4c
RSP: 0018:ffffc90003f5f810 EFLAGS: 00010203
RAX: 00000000200000ab RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88802a510000 RSI: 00000000ffffffff RDI: ffff888030a6068c
RBP: ffff88802699fb40 R08: ffff888030a606eb R09: 1ffff1100614c0dd
R10: dffffc0000000000 R11: ffffffff8718fc40 R12: dffffc0000000000
R13: ffff888030a60680 R14: 000000010000055f R15: 00000000ffffffff
FS:  00007f8d7e9236c0(0000) GS:ffff888125c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 0000000075bde000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vcc_sendmsg+0xa10/0xc60 net/atm/common.c:645
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d7e96a4a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8d7e923198 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8d7e9f4308 RCX: 00007f8d7e96a4a9
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000005
RBP: 00007f8d7e9f4300 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 65732f636f72702f R11: 0000000000000246 R12: 00007f8d7e9c10ac
R13: 00007f8d7e9231a0 R14: 0000200000000200 R15: 0000200000000250
 </TASK>
Modules linked in:

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+1741b56d54536f4ec349@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68a6767c.050a0220.3d78fd.0011.GAE@google.com/
Tested-by: syzbot+1741b56d54536f4ec349@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250821021901.2814721-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 		2025-08-22 17:23:15 -07:00
..
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Kconfig net: atm: remove support for ZeitNet ZN122x ATM devices 2022-04-27 12:22:56 +01:00
Makefile net: atm: remove support for ZeitNet ZN122x ATM devices 2022-04-27 12:22:56 +01:00
adummy.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
atmtcp.c atm: atmtcp: Prevent arbitrary write in atmtcp_recv_control(). 2025-08-22 17:23:15 -07:00
eni.c net: fill in MODULE_DESCRIPTION()s for ATM 2024-01-05 08:04:23 -08:00
eni.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fore200e.c Get rid of 'remove_new' relic from platform driver struct 2024-12-01 15:12:43 -08:00
fore200e.h atm/fore200e: Delete unused 'fore200e_boards' 2024-05-06 18:26:47 -07:00
he.c atm: he: Use the bitmap API to allocate bitmaps 2022-07-11 19:49:53 -07:00
he.h
…
idt77105.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
idt77105.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idt77252.c atm: idt77252: Add missing `dma_map_error()` 2025-06-25 15:28:57 -07:00
idt77252.h atm: idt77252: fix build broken on amd64 2021-02-15 12:36:27 -08:00
idt77252_tables.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iphase.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
iphase.h atm: Replace custom isprint() with generic analogue 2021-05-10 14:51:01 -07:00
lanai.c atm: lanai: fix "take a while" typo 2025-07-08 08:27:19 -07:00
midway.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nicstar.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
nicstar.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nicstarmac.c net: remove comments that mention obsolete __SLOW_DOWN_IO 2022-04-26 17:09:24 -07:00
nicstarmac.copyright
…
solos-attrlist.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
solos-pci.c atm: solos-pci: Fix potential deadlock on &tx_queue_lock 2023-12-09 21:17:45 +00:00
suni.c treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
suni.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tonga.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
zeprom.h atm: Fix typo 2021-05-21 13:55:32 -07:00