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Commit dd5de1f1 authored by Tomas Winkler's avatar Tomas Winkler Committed by Greg Kroah-Hartman
Browse files

mei: revamp read and write length checks 



1. Return zero on zero length read and writes
2. For a too large write return -EFBIG as defined in man write(2)
EFBIG  An attempt was made to write a file that
        exceeds the implementation-defined maximum
        file size or the process's file size limit,
        or to  write  at  a  position  past  the  maximum
        allowed offset.

Signed-off-by: default avatarTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e19555ce

drivers/misc/mei/main.c

+14 −2
Original line number Original line Diff line number Diff line
@@ -203,12 +203,18 @@ static ssize_t mei_read(struct file *file, char __user *ubuf, 




	dev = cl->dev;

	dev = cl->dev;







	mutex_lock(&dev->device_lock);

	mutex_lock(&dev->device_lock);

	if (dev->dev_state != MEI_DEV_ENABLED) {

	if (dev->dev_state != MEI_DEV_ENABLED) {

		rets = -ENODEV;

		rets = -ENODEV;

		goto out;

		goto out;

	}

	}





	if (length == 0) {

		rets = 0;

		goto out;

	}



	if (cl == &dev->iamthif_cl) {

	if (cl == &dev->iamthif_cl) {

		rets = mei_amthif_read(dev, file, ubuf, length, offset);

		rets = mei_amthif_read(dev, file, ubuf, length, offset);

		goto out;

		goto out;
@@ -350,8 +356,14 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf, 
		rets = -ENODEV;

		rets = -ENODEV;

		goto out;

		goto out;

	}

	}

	if (length > dev->me_clients[id].props.max_msg_length || length <= 0) {



		rets = -EMSGSIZE;

	if (length == 0) {

		rets = 0;

		goto out;

	}



	if (length > dev->me_clients[id].props.max_msg_length) {

		rets = -EFBIG;

		goto out;

		goto out;

	}

	}