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SubjectRe: [RFC 02/10] module: fix memory leak on early load_module() failures
On Thu, Dec 8, 2016 at 1:10 PM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
> On Thu, Dec 8, 2016 at 2:30 PM, Kees Cook <keescook@chromium.org> wrote:
>> On Thu, Dec 8, 2016 at 11:48 AM, Luis R. Rodriguez <mcgrof@kernel.org> 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@kernel.org>
>>
>> Acked-by: Kees Cook <keescook@chromium.org>
>>
>> Is this worth sending through -stable too?
>
> Yes, for some reason git-send e-mail complained to me about
> stable@kernel.org 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.

Yup, you want stable@vger.kernel.org. :)

-Kees

--
Kees Cook
Nexus Security

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