* [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure
@ 2016-10-11 12:52 Vlad Tsyrklevich
2016-10-25 9:45 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Vlad Tsyrklevich @ 2016-10-11 12:52 UTC (permalink / raw)
To: linux-i2c; +Cc: wsa, Vlad Tsyrklevich
i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.
Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
---
drivers/i2c/i2c-dev.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 66f323f..62cb111 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -393,6 +393,8 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
(data_arg.read_write == I2C_SMBUS_WRITE)) {
if (copy_from_user(&temp, data_arg.data, datasize))
return -EFAULT;
+ } else {
+ memset(&temp, 0, datasize);
}
if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
/* Convert old I2C block commands to the new
--
2.7.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure
2016-10-11 12:52 [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure Vlad Tsyrklevich
@ 2016-10-25 9:45 ` Wolfram Sang
2017-01-09 10:19 ` Vlad Tsyrklevich
0 siblings, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2016-10-25 9:45 UTC (permalink / raw)
To: Vlad Tsyrklevich; +Cc: linux-i2c
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On Tue, Oct 11, 2016 at 02:52:28PM +0200, Vlad Tsyrklevich wrote:
> i2c_smbus_xfer() does not always fill an entire block, allowing
> kernel stack memory disclosure through the temp variable. Clear
> it before it's read to.
>
> Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Yes, thanks. But what about clearing 'temp' when it is declared? This
would be rock-solid for all future code paths.
>
> ---
> drivers/i2c/i2c-dev.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
> index 66f323f..62cb111 100644
> --- a/drivers/i2c/i2c-dev.c
> +++ b/drivers/i2c/i2c-dev.c
> @@ -393,6 +393,8 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
> (data_arg.read_write == I2C_SMBUS_WRITE)) {
> if (copy_from_user(&temp, data_arg.data, datasize))
> return -EFAULT;
> + } else {
> + memset(&temp, 0, datasize);
> }
> if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
> /* Convert old I2C block commands to the new
> --
> 2.7.0
>
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure
2016-10-25 9:45 ` Wolfram Sang
@ 2017-01-09 10:19 ` Vlad Tsyrklevich
2017-01-09 14:48 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Vlad Tsyrklevich @ 2017-01-09 10:19 UTC (permalink / raw)
To: Wolfram Sang; +Cc: linux-i2c
I apologize for the long delay, this reply got lost in my inbox. I've
added an updated patch below:
i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.
Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
---
drivers/i2c/i2c-dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 66f323f..6f638bb 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -331,7 +331,7 @@ static noinline int i2cdev_ioctl_smbus(struct
i2c_client *client,
unsigned long arg)
{
struct i2c_smbus_ioctl_data data_arg;
- union i2c_smbus_data temp;
+ union i2c_smbus_data temp = {};
int datasize, res;
if (copy_from_user(&data_arg,
On Tue, Oct 25, 2016 at 4:45 PM, Wolfram Sang <wsa@the-dreams.de> wrote:
> On Tue, Oct 11, 2016 at 02:52:28PM +0200, Vlad Tsyrklevich wrote:
>> i2c_smbus_xfer() does not always fill an entire block, allowing
>> kernel stack memory disclosure through the temp variable. Clear
>> it before it's read to.
>>
>> Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
>
> Yes, thanks. But what about clearing 'temp' when it is declared? This
> would be rock-solid for all future code paths.
>
>>
>> ---
>> drivers/i2c/i2c-dev.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
>> index 66f323f..62cb111 100644
>> --- a/drivers/i2c/i2c-dev.c
>> +++ b/drivers/i2c/i2c-dev.c
>> @@ -393,6 +393,8 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
>> (data_arg.read_write == I2C_SMBUS_WRITE)) {
>> if (copy_from_user(&temp, data_arg.data, datasize))
>> return -EFAULT;
>> + } else {
>> + memset(&temp, 0, datasize);
>> }
>> if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
>> /* Convert old I2C block commands to the new
>> --
>> 2.7.0
>>
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure
@ 2017-01-09 15:53 Vlad Tsyrklevich
2017-01-12 18:36 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Vlad Tsyrklevich @ 2017-01-09 15:53 UTC (permalink / raw)
To: wsa; +Cc: linux-i2c, Vlad Tsyrklevich
i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.
Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
---
drivers/i2c/i2c-dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 66f323f..6f638bb 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -331,7 +331,7 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
unsigned long arg)
{
struct i2c_smbus_ioctl_data data_arg;
- union i2c_smbus_data temp;
+ union i2c_smbus_data temp = {};
int datasize, res;
if (copy_from_user(&data_arg,
--
2.7.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
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2016-10-11 12:52 [PATCH] drivers/i2c/i2c-dev: Fix kernel memory disclosure Vlad Tsyrklevich
2016-10-25 9:45 ` Wolfram Sang
2017-01-09 10:19 ` Vlad Tsyrklevich
2017-01-09 14:48 ` Wolfram Sang
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