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

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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?

-Kees

> ---
>  kernel/module.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index f7482db0f843..e420ed67e533 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3722,6 +3722,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
>         mod_sysfs_teardown(mod);
>   coming_cleanup:
>         mod->state = MODULE_STATE_GOING;
> +       destroy_params(mod->kp, mod->num_kp);
>         blocking_notifier_call_chain(&module_notify_list,
>                                      MODULE_STATE_GOING, mod);
>         klp_module_going(mod);
> --
> 2.10.1
>



-- 
Kees Cook
Nexus Security

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Thread

[RFC 00/10] kmod: stress test driver, few fixes and enhancements "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 19:50 +0100
  [RFC 02/10] module: fix memory leak on early load_module() failures "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
    Re: [RFC 02/10] module: fix memory leak on early load_module() failures Kees Cook <keescook@chromium.org> - 2016-12-08 21:40 +0100
      Re: [RFC 02/10] module: fix memory leak on early load_module() failures "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 22:20 +0100
        Re: [RFC 02/10] module: fix memory leak on early load_module() failures Kees Cook <keescook@chromium.org> - 2016-12-08 22:20 +0100
    Re: [RFC 02/10] module: fix memory leak on early load_module()  failures Miroslav Benes <mbenes@suse.cz> - 2016-12-09 18:10 +0100
  [RFC 08/10] sysctl: add support for unsigned int properly "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
  [RFC 05/10] kmod: return -EBUSY if modprobe limit is reached "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
  [RFC 07/10] kmod: use simplified rate limit printk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
  [RFC 04/10] kmod: provide wrappers for kmod_concurrent inc/dec "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
    Re: [RFC 04/10] kmod: provide wrappers for kmod_concurrent inc/dec Kees Cook <keescook@chromium.org> - 2016-12-08 21:40 +0100
      Re: [RFC 04/10] kmod: provide wrappers for kmod_concurrent inc/dec "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 22:10 +0100
  [RFC 06/10] kmod: provide sanity check on kmod_concurrent access "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
  [RFC 10/10] kmod: add a sanity check on module loading "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
    Re: [RFC 10/10] kmod: add a sanity check on module loading Martin Wilck <mwilck@suse.com> - 2016-12-09 21:10 +0100
      Re: [RFC 10/10] kmod: add a sanity check on module loading Linus Torvalds <torvalds@linux-foundation.org> - 2016-12-09 22:00 +0100
  [RFC 03/10] kmod: add dynamic max concurrent thread count "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100
    Re: [RFC 03/10] kmod: add dynamic max concurrent thread count Kees Cook <keescook@chromium.org> - 2016-12-08 21:30 +0100
      Re: [RFC 03/10] kmod: add dynamic max concurrent thread count "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 22:10 +0100
  [RFC 09/10] kmod: add helpers for getting kmod count and limit "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-12-08 20:50 +0100

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