diff options
| -rw-r--r-- | drivers/usb/class/usbtmc.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 4f0858fbf98..5bab8e596c8 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -369,13 +369,13 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf, { struct usbtmc_device_data *data; struct device *dev; - unsigned long int n_characters; + u32 n_characters; u8 *buffer; int actual; - int done; - int remaining; + size_t done; + size_t remaining; int retval; - int this_part; + size_t this_part; /* Get pointer to private data structure */ data = filp->private_data; @@ -461,6 +461,18 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf, (buffer[6] << 16) + (buffer[7] << 24); + /* Ensure the instrument doesn't lie about it */ + if(n_characters > actual - 12) { + dev_err(dev, "Device lies about message size: %zu > %zu\n", n_characters, actual - 12); + n_characters = actual - 12; + } + + /* Ensure the instrument doesn't send more back than requested */ + if(n_characters > this_part) { + dev_err(dev, "Device returns more than requested: %zu > %zu\n", done + n_characters, done + this_part); + n_characters = this_part; + } + /* Copy buffer to user space */ if (copy_to_user(buf + done, &buffer[12], n_characters)) { /* There must have been an addressing problem */ @@ -471,6 +483,8 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf, done += n_characters; if (n_characters < USBTMC_SIZE_IOBUFFER) remaining = 0; + else + remaining -= n_characters; } /* Update file position value */ |