From b11a88567ee81a3f9cb18c0c73f57c7ea7d765b0 Mon Sep 17 00:00:00 2001 From: Yi Zeng Date: Wed, 9 Jan 2019 15:33:07 +0800 Subject: [PATCH] i2c: dev: prevent adapter retries and timeout being set as minus value 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 [wsa: minor grammar updates to commit message] Signed-off-by: Wolfram Sang Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/i2c-dev.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index fa3ecec524fa..a07ae26c6087 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -461,9 +461,15 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 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. */