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@xxxxxxxxxxxxxxx Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> --- drivers/usb/misc/yurex.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c index 3be40eaa1ac9..1232dd49556d 100644 --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -421,13 +421,13 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer, { struct usb_yurex *dev; int i, set = 0, retval = 0; - char buffer[16]; + char buffer[16 + 1]; char *data = buffer; unsigned long long c, c2 = 0; signed long timeout = 0; DEFINE_WAIT(wait); - count = min(sizeof(buffer), count); + count = min(sizeof(buffer) - 1, count); dev = file->private_data; /* verify that we actually have some data to write */ @@ -446,6 +446,7 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer, retval = -EFAULT; goto error; } + buffer[count] = 0; memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE); switch (buffer[0]) { -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom
