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i2c: dev: prevent adapter retries and timeout being set as minus value 

If adapter->retries is set to a minus value from user space via ioctl,
it will make __i2c_transfer and __i2c_smbus_xfer skip the calling to
adapter->algo->master_xfer and adapter->algo->smbus_xfer that is
registered by the underlying bus drivers, and return value 0 to all the
callers. The bus driver will never be accessed anymore by all users,
besides, the users may still get successful return value without any
error or information log print out.

If adapter->timeout is set to minus value from user space via ioctl,
it will make the retrying loop in __i2c_transfer and __i2c_smbus_xfer
always break after the the first try, due to the time_after always
returns true.

Signed-off-by: Yi Zeng <yizeng@asrmicro.com>
[wsa: minor grammar updates to commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
This commit is contained in:
Yi Zeng 2019-01-09 15:33:07 +08:00 committed by Wolfram Sang
parent bfeffd1552
commit 6ebec961d5
1 changed files with 6 additions and 0 deletions
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6
drivers/i2c/i2c-dev.c
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@ -470,9 +470,15 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
data_arg.data);
}
case I2C_RETRIES:
if (arg > INT_MAX)
return -EINVAL;
client->adapter->retries = arg;
break;
case I2C_TIMEOUT:
if (arg > INT_MAX)
return -EINVAL;
/* For historical reasons, user-space sets the timeout
* value in units of 10 ms.
*/