CVE: CVE-2023-52570
Published: 2024-03-02
Description: In the Linux kernel, the following vulnerability has been resolved:

vfio/mdev: Fix a null-ptr-deref bug for mdev_unregister_parent()

Inject fault while probing mdpy.ko, if kstrdup() of create_dir() fails in
kobject_add_internal() in kobject_init_and_add() in mdev_type_add()
in parent_create_sysfs_files(), it will return 0 and probe successfully.
And when rmmod mdpy.ko, the mdpy_dev_exit() will call
mdev_unregister_parent(), the mdev_type_remove() may traverse uninitialized
parent->types[i] in parent_remove_sysfs_files(), and it will cause
below null-ptr-deref.

If mdev_type_add() fails, return the error code and kset_unregister()
to fix the issue.

 general protection fault, probably for non-canonical address 0xdffffc[PII_REDACTED]: 0000 [#1] PREEMPT SMP KASAN
 KASAN: null-ptr-deref in range [0x[PII_REDACTED]000010-0x[PII_REDACTED]000017]
 CPU: 2 PID: 10215 Comm: rmmod Tainted: G        W        N 6.6.0-rc2+ #20
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
 RIP: 0010:__kobject_del+0x62/0x1c0
 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8
 RSP: 0018:ffff88810695fd30 EFLAGS: 00010202
 RAX: dffffc[PII_REDACTED] RBX: ffffffffa0270268 RCX: [PII_REDACTED]
 RDX: [PII_REDACTED] RSI: [PII_REDACTED] RDI: [PII_REDACTED]
 RBP: [PII_REDACTED] R08: [PII_REDACTED] R09: ffffed10233a4ef1
 R10: ffff888119d2778b R11: [PII_REDACTED] R12: [PII_REDACTED]
 R13: fffffbfff404e2d4 R14: dffffc[PII_REDACTED] R15: ffffffffa0271660
 FS:  00007fbc81981540(0000) GS:ffff888119d00000(0000) knlGS:[PII_REDACTED]
 CS:  0010 DS: 0000 ES: 0000 CR0: [PII_REDACTED]
 CR2: 00007fc14a142dc0 CR3:[PII_REDACTED]a62003 CR4:[PII_REDACTED]770ee0
 DR0: ffffffff8fb0bce8 DR1: ffffffff8fb0bce9 DR2: ffffffff8fb0bcea
 DR3: ffffffff8fb0bceb DR6: 00000000fffe0ff0 DR7: [PII_REDACTED]
 PKRU: 55555554
 Call Trace:
  <TASK>
  ? die_addr+0x3d/0xa0
  ? exc_general_protection+0x144/0x220
  ? asm_exc_general_protection+0x22/0x30
  ? __kobject_del+0x62/0x1c0
  kobject_del+0x32/0x50
  parent_remove_sysfs_files+0xd6/0x170 [mdev]
  mdev_unregister_parent+0xfb/0x190 [mdev]
  ? mdev_register_parent+0x270/0x270 [mdev]
  ? find_module_all+0x9d/0xe0
  mdpy_dev_exit+0x17/0x63 [mdpy]
  __do_sys_delete_module.constprop.0+0x2fa/0x4b0
  ? module_flags+0x300/0x300
  ? __fput+0x4e7/0xa00
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x46/0xb0
 RIP: 0033:0x7fbc813221b7
 Code: 73 01 c3 48 8b 0d d1 8c 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 8c 2c 00 f7 d8 64 89 01 48
 RSP: 002b:00007ffe780e0648 EFLAGS: 00000206 ORIG_RAX:[PII_REDACTED]0000b0
 RAX: ffffffffffffffda RBX: 00007ffe780e06a8 RCX: 00007fbc813221b7
 RDX:[PII_REDACTED]00000a RSI: [PII_REDACTED] RDI: 000055e214df9b58
 RBP: 000055e214df9af0 R08: 00007ffe780df5c1 R09: [PII_REDACTED]
 R10: 00007fbc8139ecc0 R11: [PII_REDACTED] R12: 00007ffe780e0870
 R13: 00007ffe780e0ed0 R14: 000055e214df9260 R15: 000055e214df9af0
  </TASK>
 Modules linked in: mdpy(-) mdev vfio_iommu_type1 vfio [last unloaded: mdpy]
 Dumping ftrace buffer:
    (ftrace buffer empty)
 ---[ end trace [PII_REDACTED] ]---
 RIP: 0010:__kobject_del+0x62/0x1c0
 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8
 RSP: 0018:ffff88810695fd30 EFLAGS: 00010202
 RAX: dffffc[PII_REDACTED] RBX: ffffffffa0270268 RCX: [PII_REDACTED]
 RDX: [PII_REDACTED] RSI: [PII_REDACTED] RDI: [PII_REDACTED]
 RBP: [PII_REDACTED] R08: [PII_REDACTED] R09: ffffed10233a4ef1
 R10: ffff888119d2778b R11: [PII_REDACTED] R12: [PII_REDACTED]
 R13: fffffbfff404e2d4 R14: dffffc[PII_REDACTED] R15: ffffffffa0271660
 FS:  00007fbc81981540(0000) GS:ffff888119d00000(000
---truncated---
CVSS Score: 5.5 (MEDIUM)
CWE: CWE-476
References: https://git.kernel.org/stable/c/52093779b1830ac184a23848d971f06404cf513e; https://git.kernel.org/stable/c/c01b2e0ee22ef8b4dd7509a93aecc0ac0826bae4; https://git.kernel.org/stable/c/c777b11d34e0f47dbbc4b018ef65ad030f2b283a