CVE-2024-39502

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

ionic: fix use after netif_napi_del()

When queues are started, netif_napi_add() and napi_enable() are called.

If there are 4 queues and only 3 queues are used for the current

configuration, only 3 queues' napi should be registered and enabled.

The ionic_qcq_enable() checks whether the .poll pointer is not NULL for

enabling only the using queue' napi. Unused queues' napi will not be

registered by netif_napi_add(), so the .poll pointer indicates NULL.

But it couldn't distinguish whether the napi was unregistered or not

because netif_napi_del() doesn't reset the .poll pointer to NULL.

So, ionic_qcq_enable() calls napi_enable() for the queue, which was

unregistered by netif_napi_del().

Reproducer:

ethtool -L <interface name> rx 1 tx 1 combined 0

ethtool -L <interface name> rx 0 tx 0 combined 1

ethtool -L <interface name> rx 0 tx 0 combined 4

Splat looks like:

kernel BUG at net/core/dev.c:6666!

Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI

CPU: 3 PID: 1057 Comm: kworker/3:3 Not tainted 6.10.0-rc2+ #16

Workqueue: events ionic_lif_deferred_work [ionic]

RIP: 0010:napi_enable+0x3b/0x40

Code: 48 89 c2 48 83 e2 f6 80 b9 61 09 00 00 00 74 0d 48 83 bf 60 01 00 00 00 74 03 80 ce 01 f0 4f

RSP: 0018:ffffb6ed83227d48 EFLAGS: 00010246

RAX: 0000000000000000 RBX: ffff97560cda0828 RCX: 0000000000000029

RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff97560cda0a28

RBP: ffffb6ed83227d50 R08: 0000000000000400 R09: 0000000000000001

R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000

R13: ffff97560ce3c1a0 R14: 0000000000000000 R15: ffff975613ba0a20

FS: 0000000000000000(0000) GS:ffff975d5f780000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f8f734ee200 CR3: 0000000103e50000 CR4: 00000000007506f0

PKRU: 55555554

Call Trace:

<TASK>

? die+0x33/0x90

? do_trap+0xd9/0x100

? napi_enable+0x3b/0x40

? do_error_trap+0x83/0xb0

? napi_enable+0x3b/0x40

? napi_enable+0x3b/0x40

? exc_invalid_op+0x4e/0x70

? napi_enable+0x3b/0x40

? asm_exc_invalid_op+0x16/0x20

? napi_enable+0x3b/0x40

ionic_qcq_enable+0xb7/0x180 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]

ionic_start_queues+0xc4/0x290 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]

ionic_link_status_check+0x11c/0x170 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]

ionic_lif_deferred_work+0x129/0x280 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]

process_one_work+0x145/0x360

worker_thread+0x2bb/0x3d0

? __pfx_worker_thread+0x10/0x10

kthread+0xcc/0x100

? __pfx_kthread+0x10/0x10

ret_from_fork+0x2d/0x50

? __pfx_kthread+0x10/0x10

ret_from_fork_asm+0x1a/0x30