CVE-2024-57795

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rxe: Remove the direct link to net_device

The similar patch in siw is in the link: https://git.kernel.org/rdma/rdma/c/16b87037b48889

This problem also occurred in RXE. The following analyze this problem. In the following Call Traces:

BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0 net/core/dev.c:8782 Read of size 4 at addr ffff8880554640b0 by task kworker/1:4/5295

CPU: 1 UID: 0 PID: 5295 Comm: kworker/1:4 Not tainted 6.12.0-rc3-syzkaller-00399-g9197b73fd7bb #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: infiniband ib_cache_event_task Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 dev_get_flags+0x188/0x1d0 net/core/dev.c:8782 rxe_query_port+0x12d/0x260 drivers/infiniband/sw/rxe/rxe_verbs.c:60 __ib_query_port drivers/infiniband/core/device.c:2111 [inline] ib_query_port+0x168/0x7d0 drivers/infiniband/core/device.c:2143 ib_cache_update+0x1a9/0xb80 drivers/infiniband/core/cache.c:1494 ib_cache_event_task+0xf3/0x1e0 drivers/infiniband/core/cache.c:1568 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

1). In the link [1],

infiniband syz2: set down

This means that on 839.350575, the event ib_cache_event_task was sent andi queued in ib_wq.

2). In the link [1],

team0 (unregistering): Port device team_slave_0 removed

It indicates that before 843.251853, the net device should be freed.

3). In the link [1],

BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0

This means that on 850.559070, this slab-use-after-free problem occurred.

In all, on 839.350575, the event ib_cache_event_task was sent and queued in ib_wq,

before 843.251853, the net device veth was freed.

on 850.559070, this event was executed, and the mentioned freed net device was called. Thus, the above call trace occurred.

[1] https://syzkaller.appspot.com/x/log.txt?x=12e7025f980000

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/2ac5415022d16d63d912a39a06f32f1f51140261
• https://git.kernel.org/stable/c/9f6f54e6a6863131442b40e14d1792b090c7ce21