Re: [RFC 02/10] module: fix memory leak on early load_module() failures

[Luis R. Rodriguez]

On Thu, Dec 8, 2016 at 2:30 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Thu, Dec 8, 2016 at 11:48 AM, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote:
>> While looking for early possible module loading failures I was
>> able to reproduce a memory leak possible with kmemleak. There
>> are a few rare ways to trigger a failure:
>>
>>   o we've run into a failure while processing kernel parameters
>>     (parse_args() returns an error)
>>   o mod_sysfs_setup() fails
>>   o we're a live patch module and copy_module_elf() fails
>>
>> Chances of running into this issue is really low.
>>
>> kmemleak splat:
>>
>> unreferenced object 0xffff9f2c4ada1b00 (size 32):
>>   comm "kworker/u16:4", pid 82, jiffies 4294897636 (age 681.816s)
>>   hex dump (first 32 bytes):
>>     6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
>>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>   backtrace:
>>     [<ffffffff8c6cfeba>] kmemleak_alloc+0x4a/0xa0
>>     [<ffffffff8c200046>] __kmalloc_track_caller+0x126/0x230
>>     [<ffffffff8c1bc581>] kstrdup+0x31/0x60
>>     [<ffffffff8c1bc5d4>] kstrdup_const+0x24/0x30
>>     [<ffffffff8c3c23aa>] kvasprintf_const+0x7a/0x90
>>     [<ffffffff8c3b5481>] kobject_set_name_vargs+0x21/0x90
>>     [<ffffffff8c4fbdd7>] dev_set_name+0x47/0x50
>>     [<ffffffffc07819e5>] memstick_check+0x95/0x33c [memstick]
>>     [<ffffffff8c09c893>] process_one_work+0x1f3/0x4b0
>>     [<ffffffff8c09cb98>] worker_thread+0x48/0x4e0
>>     [<ffffffff8c0a2b79>] kthread+0xc9/0xe0
>>     [<ffffffff8c6dab5f>] ret_from_fork+0x1f/0x40
>>     [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
>
> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
>
> Is this worth sending through -stable too?

Yes, for some reason git-send e-mail complained to me about
stable@xxxxxxxxxx not being a valid local address, so I had to remove
it, but indeed. I'll try to fix this e-mail issue later and add your
tag.

 Luis