In the Linux kernel, the following vulnerability has been resolved: btrfs: prevent copying too big compressed lzo segment Compressed length can be corrupted to be a lot larger than memory we have allocated for buffer. This will cause memcpy in copy_compressed_segment to write outside of allocated memory. This mostly results in stuck read syscall but sometimes when using btrfs send can get #GP kernel: general protection fault, probably for non-canonical address 0x841551d5c1000: 0000 [#1] PREEMPT SMP NOPTI kernel: CPU: 17 PID: 264 Comm: kworker/u256:7 Tainted: P OE 5.17.0-rc2-1 #12 kernel: Workqueue: btrfs-endio btrfs_work_helper [btrfs] kernel: RIP: 0010:lzo_decompress_bio (./include/linux/fortify-string.h:225 fs/btrfs/lzo.c:322 fs/btrfs/lzo.c:394) btrfs Code starting with the faulting instruction =========================================== 0:* 48 8b 06 mov (%rsi),%rax <-- trapping instruction 3: 48 8d 79 08 lea 0x8(%rcx),%rdi 7: 48 83 e7 f8 and $0xfffffffffffffff8,%rdi b: 48 89 01 mov %rax,(%rcx) e: 44 89 f0 mov %r14d,%eax 11: 48 8b 54 06 f8 mov -0x8(%rsi,%rax,1),%rdx kernel: RSP: 0018:ffffb110812efd50 EFLAGS: 00010212 kernel: RAX: 0000000000001000 RBX: 000000009ca264c8 RCX: ffff98996e6d8ff8 kernel: RDX: 0000000000000064 RSI: 000841551d5c1000 RDI: ffffffff9500435d kernel: RBP: ffff989a3be856c0 R08: 0000000000000000 R09: 0000000000000000 kernel: R10: 0000000000000000 R11: 0000000000001000 R12: ffff98996e6d8000 kernel: R13: 0000000000000008 R14: 0000000000001000 R15: 000841551d5c1000 kernel: FS: 0000000000000000(0000) GS:ffff98a09d640000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 00001e9f984d9ea8 CR3: 000000014971a000 CR4: 00000000003506e0 kernel: Call Trace: kernel: <TASK> kernel: end_compressed_bio_read (fs/btrfs/compression.c:104 fs/btrfs/compression.c:1363 fs/btrfs/compression.c:323) btrfs kernel: end_workqueue_fn (fs/btrfs/disk-io.c:1923) btrfs kernel: btrfs_work_helper (fs/btrfs/async-thread.c:326) btrfs kernel: process_one_work (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:212 ./include/trace/events/workqueue.h:108 kernel/workqueue.c:2312) kernel: worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2455) kernel: ? process_one_work (kernel/workqueue.c:2397) kernel: kthread (kernel/kthread.c:377) kernel: ? kthread_complete_and_exit (kernel/kthread.c:332) kernel: ret_from_fork (arch/x86/entry/entry_64.S:301) kernel: </TASK>
| Métrique | Valeur | Interprétation |
|---|---|---|
|
AV (Vecteur d'Attaque)
Attack Vector
|
Local (L)
|
Exploit nécessite un accès local au système |
|
AC (Complexité d'Attaque)
Attack Complexity
|
Low (L)
|
Peu de conditions requises pour exploiter |
|
PR (Privilèges Requis)
Privileges Required
|
Low (L)
|
Authentifié avec compte utilisateur basique |
|
UI (Interaction Utilisateur)
User Interaction
|
None (N)
|
Aucune interaction utilisateur nécessaire |
|
S (Périmètre)
Scope
|
Unchanged (U)
|
Impact reste dans le périmètre du composant compromis |
|
C (Impact Confidentialité)
Confidentiality Impact
|
None (N)
|
Aucune divulgation d'informations |
|
I (Impact Intégrité)
Integrity Impact
|
None (N)
|
Aucune modification de données possible |
|
A (Impact Disponibilité)
Availability Impact
|
High (H)
|
Interruption totale du service possible |
btrfs: prevent copying too big compressed lzo segment