Re: [PATCH for-rc] RDMA/srpt: Fix UAF when srpt_add_one() failed

Junxian Huang
2024-08-01T11:34:43Z

On 2024/8/1 19:30, Leon Romanovsky wrote:
> On Thu, Aug 01, 2024 at 07:02:41PM +0800, Junxian Huang wrote:
>>
>>
>> On 2024/8/1 18:37, Leon Romanovsky wrote:
>>> On Thu, Aug 01, 2024 at 03:44:15PM +0800, Junxian Huang wrote:
>>>> Currently cancel_work_sync() is not called when srpt_refresh_port()
>>>> failed in srpt_add_one(). There is a probability that sdev has been
>>>> freed while the previously initiated sport->work is still running,
>>>> leading to a UAF as the log below:
>>>>
>>>> [ T880] ib_srpt MAD registration failed for hns_1-1.
>>>> [ T880] ib_srpt srpt_add_one(hns_1) failed.
>>>> [ T376] Unable to handle kernel paging request at virtual address 0000000000010008
>>>> ...
>>>> [ T376] Workqueue: events srpt_refresh_port_work [ib_srpt]
>>>> ...
>>>> [ T376] Call trace:
>>>> [ T376] srpt_refresh_port+0x94/0x264 [ib_srpt]
>>>> [ T376] srpt_refresh_port_work+0x1c/0x2c [ib_srpt]
>>>> [ T376] process_one_work+0x1d8/0x4cc
>>>> [ T376] worker_thread+0x158/0x410
>>>> [ T376] kthread+0x108/0x13c
>>>> [ T376] ret_from_fork+0x10/0x18
>>>>
>>>> Add cancel_work_sync() to the exception branch to fix this UAF.
>>>>
>>>> Fixes: a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
>>>> Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
>>>> ---
>>>> drivers/infiniband/ulp/srpt/ib_srpt.c | 5 +++--
>>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
>>>> index 9632afbd727b..244e5c115bf7 100644
>>>> --- a/drivers/infiniband/ulp/srpt/ib_srpt.c
>>>> +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
>>>> @@ -3148,8 +3148,8 @@ static int srpt_add_one(struct ib_device *device)
>>>> {
>>>> struct srpt_device *sdev;
>>>> struct srpt_port *sport;
>>>> + u32 i, j;
>>>> int ret;
>>>> - u32 i;
>>>>
>>>> pr_debug("device = %p\n", device);
>>>>
>>>> @@ -3226,7 +3226,6 @@ static int srpt_add_one(struct ib_device *device)
>>>> if (ret) {
>>>> pr_err("MAD registration failed for %s-%d.\n",
>>>> dev_name(&sdev->device->dev), i);
>>>> - i--;
>>>> goto err_port;
>>>> }
>>>> }
>>>> @@ -3241,6 +3240,8 @@ static int srpt_add_one(struct ib_device *device)
>>>> return 0;
>>>>
>>>> err_port:
>>>> + for (j = i, i--; j > 0; j--)a
>>>> + cancel_work_sync(&sdev->port[j - 1].work);
>>>
>>> There is no need in extra variable, the following code will do the same:
>>>
>>> while (i--)
>>> cancel_work_sync(&sdev->port[i].work);
>>>
>>>> srpt_unregister_mad_agent(sdev, i);
>>
>> i is also used here.
>
> So put cancel_work_sync() there.
>
> Thanks
>

Sure.

Junxian

>>
>> Junxian
>>
>>>> err_cm:
>>>> if (sdev->cm_id)
>>>> --
>>>> 2.33.0
>>>>
>>>
>>