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authorMax Kellermann <max.kellermann@gmail.com>2016-08-10 00:32:06 +0300
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2016-11-18 19:31:34 +0300
commitc183d3584b1777be55b4c576385143210dc0dbd5 (patch)
treec9bf00ec4432f5f3e5b6ae473ce00ff2a5500f5d
parentb68002db13f57b16b6b9f9841d40b867c298ffe4 (diff)
downloadlinux-c183d3584b1777be55b4c576385143210dc0dbd5.tar.xz
[media] rc-main: clear rc_map.name in ir_free_table()
rc_unregister_device() will first call ir_free_table(), and later device_del(); however, the latter causes a call to rc_dev_uevent(), which prints rc_map.name, which at this point has already bee freed. This fixes a use-after-free bug found with KASAN. As reported by Shuah: "I am seeing the following when I do rmmod on au0828 BUG: KASAN: use-after-free in string+0x170/0x1f0 at addr ffff8801bd513000 Read of size 1 by task rmmod/1831 CPU: 1 PID: 1831 Comm: rmmod Tainted: G W 4.9.0-rc5 #5 Hardware name: Hewlett-Packard HP ProBook 6475b/180F, BIOS 68TTU Ver. F.04 08/03/2012 ffff8801aea2f680 ffffffff81b37ad3 ffff8801fa403b80 ffff8801bd513000 ffff8801aea2f6a8 ffffffff8156c301 ffff8801aea2f738 ffff8801bd513000 ffff8801fa403b80 ffff8801aea2f728 ffffffff8156c59a ffff8801aea2f770 Call Trace: dump_stack+0x67/0x94 [<ffffffff8156c301>] kasan_object_err+0x21/0x70 [<ffffffff8156c59a>] kasan_report_error+0x1fa/0x4d0 [<ffffffffa116f05f>] ? au0828_exit+0x10/0x21 [au0828] [<ffffffff8156c8b3>] __asan_report_load1_noabort+0x43/0x50 [<ffffffff81b58b20>] ? string+0x170/0x1f0 [<ffffffff81b58b20>] string+0x170/0x1f0 [<ffffffff81b621c4>] vsnprintf+0x374/0x1c50 [<ffffffff81b61e50>] ? pointer+0xa80/0xa80 [<ffffffff8156b676>] ? save_stack+0x46/0xd0 [<ffffffff81566faa>] ? __kmalloc+0x14a/0x2a0 [<ffffffff81b3d70a>] ? kobject_get_path+0x9a/0x200 [<ffffffff81b408c2>] ? kobject_uevent_env+0x282/0xca0 [<ffffffff81b412eb>] ? kobject_uevent+0xb/0x10 [<ffffffff81f10104>] ? device_del+0x434/0x6d0 [<ffffffffa0fea717>] ? rc_unregister_device+0x177/0x240 [rc_core] [<ffffffffa116eeb0>] ? au0828_rc_unregister+0x60/0xb0 [au0828] The problem is fixed with this patch on Linux 4.9-rc4" Signed-off-by: Max Kellermann <max.kellermann@gmail.com> Tested-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
-rw-r--r--drivers/media/rc/rc-main.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index adb10fac63e4..dedaf38c5ff6 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -161,6 +161,7 @@ static void ir_free_table(struct rc_map *rc_map)
{
rc_map->size = 0;
kfree(rc_map->name);
+ rc_map->name = NULL;
kfree(rc_map->scan);
rc_map->scan = NULL;
}