Re: [PATCH AUTOSEL 4.14 036/167] driver core: platform: Fix the usage of platform device name(pdev->name)

Greg Kroah-Hartman
2019-05-22T20:06:00Z

On Wed, May 22, 2019 at 03:26:31PM -0400, Sasha Levin wrote:
> From: Venkata Narendra Kumar Gutta <vnkgutta@codeaurora.org>
>
> [ 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@codeaurora.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> drivers/base/platform.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)

Again, please just drop from everywhere.

thanks,

greg k-h