On Tue, 2018-06-26 at 09:16 +0800, Chengguang Xu wrote:
> sizeof() will return unsigned value so in the error check
> negative error code will be always larger than sizeof().
This looks like a general class of error in the kernel
where a signed result that could be returning a -errno
is tested against < or <= sizeof()
A couple examples:
drivers/input/mouse/elan_i2c_smbus.c:
len = i2c_smbus_read_block_data(client,
ETP_SMBUS_IAP_PASSWORD_READ,
val);
if (len < sizeof(u16)) {
i2c_smbus_read_block_data can return a negative errno
net/smc/smc_clc.c:
len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
sizeof(struct smc_clc_msg_decline));
if (len < sizeof(struct smc_clc_msg_decline))
where kernel_sendmsg can return a negative errno
There are probably others, I didn't look hard.
Perhaps a cocci script to find these could be generated?
On Mon, 25 Jun 2018, Joe Perches wrote:
> On Tue, 2018-06-26 at 09:16 +0800, Chengguang Xu wrote:
> > sizeof() will return unsigned value so in the error check
> > negative error code will be always larger than sizeof().
>
> This looks like a general class of error in the kernel
> where a signed result that could be returning a -errno
> is tested against < or <= sizeof()
>
> A couple examples:
>
> drivers/input/mouse/elan_i2c_smbus.c:
>
> len = i2c_smbus_read_block_data(client,
> ETP_SMBUS_IAP_PASSWORD_READ,
> val);
> if (len < sizeof(u16)) {
>
> i2c_smbus_read_block_data can return a negative errno
>
>
> net/smc/smc_clc.c:
>
> len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
> sizeof(struct smc_clc_msg_decline));
> if (len < sizeof(struct smc_clc_msg_decline))
>
> where kernel_sendmsg can return a negative errno
>
> There are probably others, I didn't look hard.
>
> Perhaps a cocci script to find these could be generated?
Currently there is a rule for comparison of unsigneds to 0. It would be
reasonable to extend it for sizes. I will see what it gives.
julia
On Mon, 25 Jun 2018, Joe Perches wrote:
> On Tue, 2018-06-26 at 09:16 +0800, Chengguang Xu wrote:
> > sizeof() will return unsigned value so in the error check
> > negative error code will be always larger than sizeof().
>
> This looks like a general class of error in the kernel
> where a signed result that could be returning a -errno
> is tested against < or <= sizeof()
>
> A couple examples:
>
> drivers/input/mouse/elan_i2c_smbus.c:
>
> len = i2c_smbus_read_block_data(client,
> ETP_SMBUS_IAP_PASSWORD_READ,
> val);
> if (len < sizeof(u16)) {
>
> i2c_smbus_read_block_data can return a negative errno
>
>
> net/smc/smc_clc.c:
>
> len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
> sizeof(struct smc_clc_msg_decline));
> if (len < sizeof(struct smc_clc_msg_decline))
>
> where kernel_sendmsg can return a negative errno
>
> There are probably others, I didn't look hard.
>
> Perhaps a cocci script to find these could be generated?
Here's another one:
drivers/usb/serial/ir-usb.c
@@ -126,13 +126,8 @@ irda_usb_find_class_desc(struct usb_seri
if (!desc)
return NULL;
- ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
- USB_REQ_CS_IRDA_GET_CLASS_DESC,
- USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
- 0, ifnum, desc, sizeof(*desc), 1000);
dev_dbg(&serial->dev->dev, "%s - ret=%d\n", __func__, ret);
- if (ret < sizeof(*desc)) {
dev_dbg(&serial->dev->dev,
"%s - class descriptor read %s (%d)\n", __func__,
(ret < 0) ? "failed" : "too short", ret);
There are other results, but I haven't checked all of them.
julia
On 06/26/2018 04:06 PM, Julia Lawall wrote:
>
> On Mon, 25 Jun 2018, Joe Perches wrote:
>
>> On Tue, 2018-06-26 at 09:16 +0800, Chengguang Xu wrote:
>>> sizeof() will return unsigned value so in the error check
>>> negative error code will be always larger than sizeof().
>> This looks like a general class of error in the kernel
>> where a signed result that could be returning a -errno
>> is tested against < or <= sizeof()
>>
>> A couple examples:
>>
>> drivers/input/mouse/elan_i2c_smbus.c:
>>
>> len = i2c_smbus_read_block_data(client,
>> ETP_SMBUS_IAP_PASSWORD_READ,
>> val);
>> if (len < sizeof(u16)) {
>>
>> i2c_smbus_read_block_data can return a negative errno
>>
>>
>> net/smc/smc_clc.c:
>>
>> len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
>> sizeof(struct smc_clc_msg_decline));
>> if (len < sizeof(struct smc_clc_msg_decline))
>>
>> where kernel_sendmsg can return a negative errno
>>
>> There are probably others, I didn't look hard.
>>
>> Perhaps a cocci script to find these could be generated?
> Here's another one:
>
> drivers/usb/serial/ir-usb.c
> @@ -126,13 +126,8 @@ irda_usb_find_class_desc(struct usb_seri
> if (!desc)
> return NULL;
>
> - ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
> - USB_REQ_CS_IRDA_GET_CLASS_DESC,
> - USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> - 0, ifnum, desc, sizeof(*desc), 1000);
>
> dev_dbg(&serial->dev->dev, "%s - ret=%d\n", __func__, ret);
> - if (ret < sizeof(*desc)) {
> dev_dbg(&serial->dev->dev,
> "%s - class descriptor read %s (%d)\n", __func__,
> (ret < 0) ? "failed" : "too short", ret);
>
> There are other results, but I haven't checked all of them.
Hi Julia,
Thanks for your check. I posted a patch yesterday to fix three places in
usb subsystem
and the patch is just in queue now, so you can skip these places.
The detail of patch.
---
diff --git a/drivers/usb/serial/ir-usb.c b/drivers/usb/serial/ir-usb.c
index 24b06c7e5e2d..7643716b5299 100644
--- a/drivers/usb/serial/ir-usb.c
+++ b/drivers/usb/serial/ir-usb.c
@@ -132,7 +132,7 @@ irda_usb_find_class_desc(struct usb_serial *serial, unsigned int ifnum)
0, ifnum, desc, sizeof(*desc), 1000);
dev_dbg(&serial->dev->dev, "%s - ret=%d\n", __func__, ret);
- if (ret < sizeof(*desc)) {
+ if (ret < (int)sizeof(*desc)) {
dev_dbg(&serial->dev->dev,
"%s - class descriptor read %s (%d)\n", __func__,
(ret < 0) ? "failed" : "too short", ret);
diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index 958e12e1e7c7..ff2322ea5e14 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -194,7 +194,7 @@ static inline int qt2_getregister(struct usb_device *dev,
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
QT_SET_GET_REGISTER, 0xc0, reg,
uart, data, sizeof(*data), QT2_USB_TIMEOUT);
- if (ret < sizeof(*data)) {
+ if (ret < (int)sizeof(*data)) {
if (ret >= 0)
ret = -EIO;
}
diff --git a/drivers/usb/serial/ssu100.c b/drivers/usb/serial/ssu100.c
index 2083c267787b..0900b47b5f57 100644
--- a/drivers/usb/serial/ssu100.c
+++ b/drivers/usb/serial/ssu100.c
@@ -104,7 +104,7 @@ static inline int ssu100_getregister(struct usb_device *dev,
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
QT_SET_GET_REGISTER, 0xc0, reg,
uart, data, sizeof(*data), 300);
- if (ret < sizeof(*data)) {
+ if (ret < (int)sizeof(*data)) {
if (ret >= 0)
ret = -EIO;
}
---
Thanks,
Chengguang.