2018-02-05 11:35:55

by William Wu

[permalink] [raw]
Subject: [PATCH] usb: gadget: f_fs: get the correct address of comp_desc

Refer to the USB 3.0 spec '9.6.7 SuperSpeed Endpoint Companion',
the companion descriptor follows the standard endpoint descriptor.
This descriptor is only defined for SuperSpeed endpoints. The
f_fs driver gets the address of the companion descriptor via
'ds + USB_DT_ENDPOINT_SIZE', and actually, the ds variable is
a pointer to the struct usb_endpoint_descriptor, so the offset
of the companion descriptor which we get is USB_DT_ENDPOINT_SIZE *
sizeof(struct usb_endpoint_descriptor), the wrong offset is 63
bytes. This cause out-of-bound with the following error log if
CONFIG_KASAN and CONFIG_SLUB_DEBUG is enabled on Rockchip RK3399
Evaluation Board.

android_work: sent uevent USB_STATE=CONNECTED
configfs-gadget gadget: super-speed config #1: b
==================================================================
BUG: KASAN: slab-out-of-bounds in ffs_func_set_alt+0x230/0x398
Read of size 1 at addr ffffffc0ce2d0b10 by task irq/224-dwc3/364

CPU: 4 PID: 364 Comm: irq/224-dwc3 Not tainted 4.4.112 #6
Hardware name: Rockchip RK3399 Evaluation Board v3 (Android) (DT)
Call trace:
[<ffffff900808c4a4>] dump_backtrace+0x0/0x244
[<ffffff900808c6fc>] show_stack+0x14/0x1c
[<ffffff90084f0ff4>] dump_stack+0xa4/0xcc
[<ffffff900822d054>] print_address_description+0xa4/0x308
[<ffffff900822d5bc>] kasan_report+0x258/0x29c
[<ffffff900822bb28>] __asan_load1+0x44/0x4c
[<ffffff9008b6eec4>] ffs_func_set_alt+0x230/0x398
[<ffffff9008b56e5c>] composite_setup+0xdcc/0x1ac8
[<ffffff9008b5aaa4>] android_setup+0x124/0x1a0
[<ffffff9008aa22b4>] dwc3_ep0_delegate_req+0x48/0x68
[<ffffff9008aa3248>] dwc3_ep0_interrupt+0x758/0x1174
[<ffffff9008a9f688>] dwc3_thread_interrupt+0x204/0xe68
[<ffffff9008126c04>] irq_thread_fn+0x44/0x94
[<ffffff9008126e44>] irq_thread+0x128/0x22c
[<ffffff90080d39c4>] kthread+0x11c/0x130
[<ffffff90080832a0>] ret_from_fork+0x10/0x30

Allocated by task 1:
[<ffffff900808bf0c>] save_stack_trace_tsk+0x0/0x134
[<ffffff900808c054>] save_stack_trace+0x14/0x1c
[<ffffff900822c188>] kasan_kmalloc.part.3+0x48/0xf4
[<ffffff900822c3c8>] kasan_kmalloc+0x8c/0xa0
[<ffffff9008229990>] __kmalloc+0x208/0x268
[<ffffff9008b71258>] ffs_func_bind+0x4b4/0x918
[<ffffff9008b55168>] usb_add_function+0xd8/0x1d4
[<ffffff9008b5b204>] configfs_composite_bind+0x48c/0x570
[<ffffff9008b5dc80>] udc_bind_to_driver+0x6c/0x170
[<ffffff9008b5de28>] usb_udc_attach_driver+0xa4/0xd0
[<ffffff9008b5c110>] gadget_dev_desc_UDC_store+0xd4/0x120
[<ffffff90082d6014>] configfs_write_file+0x1a0/0x1f8
[<ffffff9008237960>] __vfs_write+0x64/0x174
[<ffffff9008238560>] vfs_write+0xe4/0x1e8
[<ffffff90082392fc>] SyS_write+0x68/0xc8
[<ffffff90080832f0>] el0_svc_naked+0x24/0x28

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffffffc0ce2d0900
which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 528 bytes inside of
1024-byte region [ffffffc0ce2d0900, ffffffc0ce2d0d00)
The buggy address belongs to the page:
page:ffffffbdc338b400 count:1 mapcount:-2145648611 mapping: (null) index:0x0
flags: 0x4080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffffffc0ce2d0a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffc0ce2d0a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffc0ce2d0b00: 00 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffffffc0ce2d0b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffffffc0ce2d0c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Disabling lock debugging due to kernel taint
android_work: sent uevent USB_STATE=CONFIGURED

This patch adds struct usb_endpoint_descriptor * -> u8 * type conversion
for ds variable, then we can get the correct address of comp_desc
with offset USB_DT_ENDPOINT_SIZE bytes.

Signed-off-by: William Wu <[email protected]>
---
drivers/usb/gadget/function/f_fs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 6756472..f13ead0 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1882,8 +1882,8 @@ static int ffs_func_eps_enable(struct ffs_function *func)
ep->ep->desc = ds;

if (needs_comp_desc) {
- comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
- USB_DT_ENDPOINT_SIZE);
+ comp_desc = (struct usb_ss_ep_comp_descriptor *)
+ ((u8 *)ds + USB_DT_ENDPOINT_SIZE);
ep->ep->maxburst = comp_desc->bMaxBurst + 1;
ep->ep->comp_desc = comp_desc;
}
--
2.0.0




2018-02-05 18:21:16

by Jack Pham

[permalink] [raw]
Subject: Re: [PATCH] usb: gadget: f_fs: get the correct address of comp_desc

Hi William,

On Mon, Feb 05, 2018 at 07:33:38PM +0800, William Wu wrote:
> Refer to the USB 3.0 spec '9.6.7 SuperSpeed Endpoint Companion',
> the companion descriptor follows the standard endpoint descriptor.
> This descriptor is only defined for SuperSpeed endpoints. The
> f_fs driver gets the address of the companion descriptor via
> 'ds + USB_DT_ENDPOINT_SIZE', and actually, the ds variable is
> a pointer to the struct usb_endpoint_descriptor, so the offset
> of the companion descriptor which we get is USB_DT_ENDPOINT_SIZE *
> sizeof(struct usb_endpoint_descriptor), the wrong offset is 63
> bytes. This cause out-of-bound with the following error log if
> CONFIG_KASAN and CONFIG_SLUB_DEBUG is enabled on Rockchip RK3399
> Evaluation Board.
>
> android_work: sent uevent USB_STATE=CONNECTED
> configfs-gadget gadget: super-speed config #1: b
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in ffs_func_set_alt+0x230/0x398
> Read of size 1 at addr ffffffc0ce2d0b10 by task irq/224-dwc3/364

> Memory state around the buggy address:
> ffffffc0ce2d0a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffffffc0ce2d0a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffffc0ce2d0b00: 00 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ^
> ffffffc0ce2d0b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffffffc0ce2d0c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
> Disabling lock debugging due to kernel taint
> android_work: sent uevent USB_STATE=CONFIGURED
>
> This patch adds struct usb_endpoint_descriptor * -> u8 * type conversion
> for ds variable, then we can get the correct address of comp_desc
> with offset USB_DT_ENDPOINT_SIZE bytes.
>
> Signed-off-by: William Wu <[email protected]>
> ---
> drivers/usb/gadget/function/f_fs.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 6756472..f13ead0 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -1882,8 +1882,8 @@ static int ffs_func_eps_enable(struct ffs_function *func)
> ep->ep->desc = ds;
>
> if (needs_comp_desc) {
> - comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
> - USB_DT_ENDPOINT_SIZE);
> + comp_desc = (struct usb_ss_ep_comp_descriptor *)
> + ((u8 *)ds + USB_DT_ENDPOINT_SIZE);
> ep->ep->maxburst = comp_desc->bMaxBurst + 1;
> ep->ep->comp_desc = comp_desc;
> }

Please see my alternative fix for this. I proposed changing this
function to use config_ep_by_speed() instead.

https://www.spinics.net/lists/linux-usb/msg165149.html

Jack
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

2018-02-06 14:12:52

by wlf

[permalink] [raw]
Subject: Re: [PATCH] usb: gadget: f_fs: get the correct address of comp_desc

Hi Jack,

在 2018年02月06日 02:17, Jack Pham 写道:
> Hi William,
>
> On Mon, Feb 05, 2018 at 07:33:38PM +0800, William Wu wrote:
>> Refer to the USB 3.0 spec '9.6.7 SuperSpeed Endpoint Companion',
>> the companion descriptor follows the standard endpoint descriptor.
>> This descriptor is only defined for SuperSpeed endpoints. The
>> f_fs driver gets the address of the companion descriptor via
>> 'ds + USB_DT_ENDPOINT_SIZE', and actually, the ds variable is
>> a pointer to the struct usb_endpoint_descriptor, so the offset
>> of the companion descriptor which we get is USB_DT_ENDPOINT_SIZE *
>> sizeof(struct usb_endpoint_descriptor), the wrong offset is 63
>> bytes. This cause out-of-bound with the following error log if
>> CONFIG_KASAN and CONFIG_SLUB_DEBUG is enabled on Rockchip RK3399
>> Evaluation Board.
>>
>> android_work: sent uevent USB_STATE=CONNECTED
>> configfs-gadget gadget: super-speed config #1: b
>> ==================================================================
>> BUG: KASAN: slab-out-of-bounds in ffs_func_set_alt+0x230/0x398
>> Read of size 1 at addr ffffffc0ce2d0b10 by task irq/224-dwc3/364
>> Memory state around the buggy address:
>> ffffffc0ce2d0a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> ffffffc0ce2d0a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> >ffffffc0ce2d0b00: 00 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>> ^
>> ffffffc0ce2d0b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>> ffffffc0ce2d0c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>> ==================================================================
>> Disabling lock debugging due to kernel taint
>> android_work: sent uevent USB_STATE=CONFIGURED
>>
>> This patch adds struct usb_endpoint_descriptor * -> u8 * type conversion
>> for ds variable, then we can get the correct address of comp_desc
>> with offset USB_DT_ENDPOINT_SIZE bytes.
>>
>> Signed-off-by: William Wu <[email protected]>
>> ---
>> drivers/usb/gadget/function/f_fs.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
>> index 6756472..f13ead0 100644
>> --- a/drivers/usb/gadget/function/f_fs.c
>> +++ b/drivers/usb/gadget/function/f_fs.c
>> @@ -1882,8 +1882,8 @@ static int ffs_func_eps_enable(struct ffs_function *func)
>> ep->ep->desc = ds;
>>
>> if (needs_comp_desc) {
>> - comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
>> - USB_DT_ENDPOINT_SIZE);
>> + comp_desc = (struct usb_ss_ep_comp_descriptor *)
>> + ((u8 *)ds + USB_DT_ENDPOINT_SIZE);
>> ep->ep->maxburst = comp_desc->bMaxBurst + 1;
>> ep->ep->comp_desc = comp_desc;
>> }
> Please see my alternative fix for this. I proposed changing this
> function to use config_ep_by_speed() instead.
>
> https://www.spinics.net/lists/linux-usb/msg165149.html
Thanks for your great job!
 Your patch seems good, I will test your patch on my RK3399-EVB board.

William

>
> Jack