2022-05-09 05:12:57

by Wang Cheng

[permalink] [raw]
Subject: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

When r8712_usbctrl_vendorreq() returns negative, 'data' in
usb_read{8,16,32} will not be initialized.

BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KMSAN: uninit-value in string+0x4ec/0x6f0 lib/vsprintf.c:725
string_nocheck lib/vsprintf.c:643 [inline]
string+0x4ec/0x6f0 lib/vsprintf.c:725
vsnprintf+0x2222/0x3650 lib/vsprintf.c:2806
va_format lib/vsprintf.c:1704 [inline]
pointer+0x18e6/0x1f70 lib/vsprintf.c:2443
vsnprintf+0x1a9b/0x3650 lib/vsprintf.c:2810
vprintk_store+0x537/0x2150 kernel/printk/printk.c:2158
vprintk_emit+0x28b/0xab0 kernel/printk/printk.c:2256
dev_vprintk_emit+0x5ef/0x6d0 drivers/base/core.c:4604
dev_printk_emit+0x1dd/0x21f drivers/base/core.c:4615
__dev_printk+0x3be/0x440 drivers/base/core.c:4627
_dev_info+0x1ea/0x22f drivers/base/core.c:4673
r871xu_drv_init+0x1929/0x3070 drivers/staging/rtl8712/usb_intf.c:401
usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396
really_probe+0x6c7/0x1350 drivers/base/dd.c:621
__driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
driver_probe_device drivers/base/dd.c:782 [inline]
__device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
__device_attach+0x593/0x8e0 drivers/base/dd.c:970
device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
device_add+0x1fff/0x26e0 drivers/base/core.c:3405
usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170
usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238
usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293
really_probe+0x6c7/0x1350 drivers/base/dd.c:621
__driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
driver_probe_device drivers/base/dd.c:782 [inline]
__device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
__device_attach+0x593/0x8e0 drivers/base/dd.c:970
device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
device_add+0x1fff/0x26e0 drivers/base/core.c:3405
usb_new_device+0x1b91/0x2950 drivers/usb/core/hub.c:2566
hub_port_connect drivers/usb/core/hub.c:5363 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5507 [inline]
port_event drivers/usb/core/hub.c:5665 [inline]
hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5747
process_one_work+0xdb6/0x1820 kernel/workqueue.c:2289
worker_thread+0x10d0/0x2240 kernel/workqueue.c:2436
kthread+0x3c7/0x500 kernel/kthread.c:376
ret_from_fork+0x1f/0x30

Local variable data created at:
usb_read8+0x5d/0x130 drivers/staging/rtl8712/usb_ops.c:33
r8712_read8+0xa5/0xd0 drivers/staging/rtl8712/rtl8712_io.c:29

Reported-and-tested-by: [email protected]
Signed-off-by: Wang Cheng <[email protected]>
---
drivers/staging/rtl8712/usb_ops.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/rtl8712/usb_ops.c b/drivers/staging/rtl8712/usb_ops.c
index e64845e6adf3..af9966d03979 100644
--- a/drivers/staging/rtl8712/usb_ops.c
+++ b/drivers/staging/rtl8712/usb_ops.c
@@ -29,7 +29,8 @@ static u8 usb_read8(struct intf_hdl *intfhdl, u32 addr)
u16 wvalue;
u16 index;
u16 len;
- __le32 data;
+ int status;
+ __le32 data = 0;
struct intf_priv *intfpriv = intfhdl->pintfpriv;

request = 0x05;
@@ -37,8 +38,10 @@ static u8 usb_read8(struct intf_hdl *intfhdl, u32 addr)
index = 0;
wvalue = (u16)(addr & 0x0000ffff);
len = 1;
- r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
- requesttype);
+ status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+ &data, len, requesttype);
+ if (status < 0)
+ return 0;
return (u8)(le32_to_cpu(data) & 0x0ff);
}

@@ -49,7 +52,8 @@ static u16 usb_read16(struct intf_hdl *intfhdl, u32 addr)
u16 wvalue;
u16 index;
u16 len;
- __le32 data;
+ int status;
+ __le32 data = 0;
struct intf_priv *intfpriv = intfhdl->pintfpriv;

request = 0x05;
@@ -57,8 +61,10 @@ static u16 usb_read16(struct intf_hdl *intfhdl, u32 addr)
index = 0;
wvalue = (u16)(addr & 0x0000ffff);
len = 2;
- r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
- requesttype);
+ status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+ &data, len, requesttype);
+ if (status < 0)
+ return 0;
return (u16)(le32_to_cpu(data) & 0xffff);
}

@@ -69,7 +75,8 @@ static u32 usb_read32(struct intf_hdl *intfhdl, u32 addr)
u16 wvalue;
u16 index;
u16 len;
- __le32 data;
+ int status;
+ __le32 data = 0;
struct intf_priv *intfpriv = intfhdl->pintfpriv;

request = 0x05;
@@ -77,8 +84,10 @@ static u32 usb_read32(struct intf_hdl *intfhdl, u32 addr)
index = 0;
wvalue = (u16)(addr & 0x0000ffff);
len = 4;
- r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
- requesttype);
+ status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+ &data, len, requesttype);
+ if (status < 0)
+ return 0;
return le32_to_cpu(data);
}

--
2.33.1



2022-05-09 09:10:47

by Pavel Skripkin

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

Hi Wang,

On 5/6/22 06:15, Wang Cheng wrote:
> When r8712_usbctrl_vendorreq() returns negative, 'data' in
> usb_read{8,16,32} will not be initialized.

[code snip]

> + status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
> + &data, len, requesttype);
> + if (status < 0)
> + return 0;
> return le32_to_cpu(data);
> }
>

Why do you believe that 0 is not valid register value? And if it's
possible then how you can identify an error?




With regards,
Pavel Skripkin

2022-05-09 09:48:50

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

Setting "data = 0" will silence the KMSAN warnings but it doesn't fix
the bug which is that r8712_usbctrl_vendorreq() treats partial reads
as success.

The usb_control_msg() returns negatives on total failure and it returns
small positives on partial failure. So take the code that I gave you
before and put that into r8712_usbctrl_vendorreq(). That's patch 1.
These patches become 2 and 3.

status = usb_control_msg();
if (status < 0)
goto free;
if (status != len) {
status = -EREMOTEIO;
goto free;
}
if (requesttype == 0x01)
memcpy(pdata, pIo_buf, status);

regards,
dan carpenter