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Commit a383de0d authored by Ben Hutchings's avatar Ben Hutchings Committed by Greg Kroah-Hartman
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USB: yurex: Fix buffer over-read in yurex_write() 

commit 7e10f14ebface44a48275c8d6dc1caae3668d5a9 upstream.

If the written data starts with a digit, yurex_write() tries to parse
it as an integer using simple_strtoull().  This requires a null-
terminator, and currently there's no guarantee that there is one.

(The sample program at
https://github.com/NeoCat/YUREX-driver-for-Linux/blob/master/sample/yurex_clock.pl


writes an integer without a null terminator.  It seems like it must
have worked by chance!)

Always add a null byte after the written data.  Enlarge the buffer
to allow for this.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a98152a6

drivers/usb/misc/yurex.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -425,13 +425,13 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer, 
{

{

	struct usb_yurex *dev;

	struct usb_yurex *dev;

	int i, set = 0, retval = 0;

	int i, set = 0, retval = 0;

	char buffer[16];

	char buffer[16 + 1];

	char *data = buffer;

	char *data = buffer;

	unsigned long long c, c2 = 0;

	unsigned long long c, c2 = 0;

	signed long timeout = 0;

	signed long timeout = 0;

	DEFINE_WAIT(wait);

	DEFINE_WAIT(wait);





	count = min(sizeof(buffer), count);

	count = min(sizeof(buffer) - 1, count);

	dev = file->private_data;

	dev = file->private_data;





	/* verify that we actually have some data to write */

	/* verify that we actually have some data to write */
@@ -450,6 +450,7 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer, 
		retval = -EFAULT;

		retval = -EFAULT;

		goto error;

		goto error;

	}

	}

	buffer[count] = 0;

	memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE);

	memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE);





	switch (buffer[0]) {

	switch (buffer[0]) {