CVE-2022-48811

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

ibmvnic: dont release napi in __ibmvnic_open()

If __ibmvnic_open() encounters an error such as when setting link state, it calls release_resources() which frees the napi structures needlessly. Instead, have __ibmvnic_open() only clean up the work it did so far (i.e. disable napi and irqs) and leave the rest to the callers.

If caller of __ibmvnic_open() is ibmvnic_open(), it should release the resources immediately. If the caller is do_reset() or do_hard_reset(), they will release the resources on the next reset.

This fixes following crash that occurred when running the drmgr command several times to add/remove a vnic interface:

[102056] ibmvnic 30000003 env3: Disabling rx_scrq[6] irq
[102056] ibmvnic 30000003 env3: Disabling rx_scrq[7] irq
[102056] ibmvnic 30000003 env3: Replenished 8 pools
Kernel attempted to read user page (10) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on read at 0x00000010
Faulting instruction address: 0xc000000000a3c840
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
...
CPU: 9 PID: 102056 Comm: kworker/9:2 Kdump: loaded Not tainted 5.16.0-rc5-autotest-g6441998e2e37 #1
Workqueue: events_long __ibmvnic_reset [ibmvnic]
NIP:  c000000000a3c840 LR: c0080000029b5378 CTR: c000000000a3c820
REGS: c0000000548e37e0 TRAP: 0300   Not tainted  (5.16.0-rc5-autotest-g6441998e2e37)
MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28248484  XER: 00000004
CFAR: c0080000029bdd24 DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0
GPR00: c0080000029b55d0 c0000000548e3a80 c0000000028f0200 0000000000000000
...
NIP [c000000000a3c840] napi_enable+0x20/0xc0
LR [c0080000029b5378] __ibmvnic_open+0xf0/0x430 [ibmvnic]
Call Trace:
[c0000000548e3a80] [0000000000000006] 0x6 (unreliable)
[c0000000548e3ab0] [c0080000029b55d0] __ibmvnic_open+0x348/0x430 [ibmvnic]
[c0000000548e3b40] [c0080000029bcc28] __ibmvnic_reset+0x500/0xdf0 [ibmvnic]
[c0000000548e3c60] [c000000000176228] process_one_work+0x288/0x570
[c0000000548e3d00] [c000000000176588] worker_thread+0x78/0x660
[c0000000548e3da0] [c0000000001822f0] kthread+0x1c0/0x1d0
[c0000000548e3e10] [c00000000000cf64] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
7d2948f8 792307e0 4e800020 60000000 3c4c01eb 384239e0 f821ffd1 39430010
38a0fff6 e92d1100 f9210028 39200000 <e9030010> f9010020 60420000 e9210020
---[ end trace 5f8033b08fd27706 ]---

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/61772b0908c640d0309c40f7d41d062ca4e979fa
• https://git.kernel.org/stable/c/960dfaf3b578dd23af012590e809ae2d58ba1827
• https://git.kernel.org/stable/c/e08cb9056fb2564d1f6bad789bdf79ab09bf2f81
• https://git.kernel.org/stable/c/61772b0908c640d0309c40f7d41d062ca4e979fa
• https://git.kernel.org/stable/c/960dfaf3b578dd23af012590e809ae2d58ba1827
• https://git.kernel.org/stable/c/e08cb9056fb2564d1f6bad789bdf79ab09bf2f81