Re: [PATCH AUTOSEL 5.1 06/60] driver core: platform: Fix the usage of platform device name(pdev->name)

From: Sasha Levin
Date: Sat Jun 15 2019 - 18:31:37 EST


On Wed, Jun 05, 2019 at 06:58:46AM +0200, Greg Kroah-Hartman wrote:
On Tue, Jun 04, 2019 at 07:21:16PM -0400, Sasha Levin wrote:
From: Venkata Narendra Kumar Gutta <vnkgutta@xxxxxxxxxxxxxx>

[ Upstream commit edb16da34b084c66763f29bee42b4e6bb33c3d66 ]

Platform core is using pdev->name as the platform device name to do
the binding of the devices with the drivers. But, when the platform
driver overrides the platform device name with dev_set_name(),
the pdev->name is pointing to a location which is freed and becomes
an invalid parameter to do the binding match.

use-after-free instance:

[ 33.325013] BUG: KASAN: use-after-free in strcmp+0x8c/0xb0
[ 33.330646] Read of size 1 at addr ffffffc10beae600 by task modprobe
[ 33.339068] CPU: 5 PID: 518 Comm: modprobe Tainted:
G S W O 4.19.30+ #3
[ 33.346835] Hardware name: MTP (DT)
[ 33.350419] Call trace:
[ 33.352941] dump_backtrace+0x0/0x3b8
[ 33.356713] show_stack+0x24/0x30
[ 33.360119] dump_stack+0x160/0x1d8
[ 33.363709] print_address_description+0x84/0x2e0
[ 33.368549] kasan_report+0x26c/0x2d0
[ 33.372322] __asan_report_load1_noabort+0x2c/0x38
[ 33.377248] strcmp+0x8c/0xb0
[ 33.380306] platform_match+0x70/0x1f8
[ 33.384168] __driver_attach+0x78/0x3a0
[ 33.388111] bus_for_each_dev+0x13c/0x1b8
[ 33.392237] driver_attach+0x4c/0x58
[ 33.395910] bus_add_driver+0x350/0x560
[ 33.399854] driver_register+0x23c/0x328
[ 33.403886] __platform_driver_register+0xd0/0xe0

So, use dev_name(&pdev->dev), which fetches the platform device name from
the kobject(dev->kobj->name) of the device instead of the pdev->name.

Signed-off-by: Venkata Narendra Kumar Gutta <vnkgutta@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/base/platform.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

Please drop this from everywhere as it was reverted from Linus's tree
because it causes big problems.

Dropped from all branches, thanks!

--
Thanks,
Sasha