4.9-stable review patch. If anyone has any objections, please let me know.
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From: Yi Zeng yizeng@asrmicro.com
commit 6ebec961d59bccf65d08b13fc1ad4e6272a89338 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/i2c-dev.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -461,9 +461,15 @@ static long i2cdev_ioctl(struct file *fi return i2cdev_ioctl_smbus(client, arg);
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. */