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

Junxian Huang
2024-08-01T11:02:45Z

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.

Junxian

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