linux-kernel - [PATCH 4.10 163/167] module: fix memory leak on early load

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Date:   Fri, 10 Mar 2017 10:10:06 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Miroslav Benes <mbenes@...e.cz>,
        Aaron Tomlin <atomlin@...hat.com>,
        Rusty Russell <rusty@...tcorp.com.au>,
        Kees Cook <keescook@...omium.org>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Jessica Yu <jeyu@...hat.com>
Subject: [PATCH 4.10 163/167] module: fix memory leak on early load_module() failures

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Luis R. Rodriguez <mcgrof@...nel.org>

commit a5544880aff90baf1bd4443ac7ff65182213ffcd upstream.

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

Fixes: e180a6b7759a ("param: fix charp parameters set via sysfs")
Reviewed-by: Miroslav Benes <mbenes@...e.cz>
Reviewed-by: Aaron Tomlin <atomlin@...hat.com>
Reviewed-by: Rusty Russell <rusty@...tcorp.com.au>
Acked-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
Signed-off-by: Jessica Yu <jeyu@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 kernel/module.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3719,6 +3719,7 @@ static int load_module(struct load_info
 	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);