From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 20 Apr 2017 19:47:34 +0000 (-0400)
Subject: spidev: quit messing with access_ok()
X-Git-Tag: v4.13-rc1~96^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=251d59515fe4681a64a8bc7e37cfa00701e0f9b0;p=karo-tx-linux.git

spidev: quit messing with access_ok()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 9a2a79a871ba..221741f38260 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -254,10 +254,6 @@ static int spidev_message(struct spidev_data *spidev,
 				goto done;
 			}
 			k_tmp->rx_buf = rx_buf;
-			if (!access_ok(VERIFY_WRITE, (u8 __user *)
-						(uintptr_t) u_tmp->rx_buf,
-						u_tmp->len))
-				goto done;
 			rx_buf += k_tmp->len;
 		}
 		if (u_tmp->tx_buf) {
@@ -305,7 +301,7 @@ static int spidev_message(struct spidev_data *spidev,
 	rx_buf = spidev->rx_buffer;
 	for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
 		if (u_tmp->rx_buf) {
-			if (__copy_to_user((u8 __user *)
+			if (copy_to_user((u8 __user *)
 					(uintptr_t) u_tmp->rx_buf, rx_buf,
 					u_tmp->len)) {
 				status = -EFAULT;
@@ -355,7 +351,6 @@ spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
 static long
 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	int			err = 0;
 	int			retval = 0;
 	struct spidev_data	*spidev;
 	struct spi_device	*spi;
@@ -367,19 +362,6 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
 		return -ENOTTY;
 
-	/* Check access direction once here; don't repeat below.
-	 * IOC_DIR is from the user perspective, while access_ok is
-	 * from the kernel perspective; so they look reversed.
-	 */
-	if (_IOC_DIR(cmd) & _IOC_READ)
-		err = !access_ok(VERIFY_WRITE,
-				(void __user *)arg, _IOC_SIZE(cmd));
-	if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
-		err = !access_ok(VERIFY_READ,
-				(void __user *)arg, _IOC_SIZE(cmd));
-	if (err)
-		return -EFAULT;
-
 	/* guard against device removal before, or while,
 	 * we issue this ioctl.
 	 */
@@ -402,31 +384,31 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	switch (cmd) {
 	/* read requests */
 	case SPI_IOC_RD_MODE:
-		retval = __put_user(spi->mode & SPI_MODE_MASK,
+		retval = put_user(spi->mode & SPI_MODE_MASK,
 					(__u8 __user *)arg);
 		break;
 	case SPI_IOC_RD_MODE32:
-		retval = __put_user(spi->mode & SPI_MODE_MASK,
+		retval = put_user(spi->mode & SPI_MODE_MASK,
 					(__u32 __user *)arg);
 		break;
 	case SPI_IOC_RD_LSB_FIRST:
-		retval = __put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
+		retval = put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
 					(__u8 __user *)arg);
 		break;
 	case SPI_IOC_RD_BITS_PER_WORD:
-		retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
+		retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
 		break;
 	case SPI_IOC_RD_MAX_SPEED_HZ:
-		retval = __put_user(spidev->speed_hz, (__u32 __user *)arg);
+		retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
 		break;
 
 	/* write requests */
 	case SPI_IOC_WR_MODE:
 	case SPI_IOC_WR_MODE32:
 		if (cmd == SPI_IOC_WR_MODE)
-			retval = __get_user(tmp, (u8 __user *)arg);
+			retval = get_user(tmp, (u8 __user *)arg);
 		else
-			retval = __get_user(tmp, (u32 __user *)arg);
+			retval = get_user(tmp, (u32 __user *)arg);
 		if (retval == 0) {
 			u32	save = spi->mode;
 
@@ -445,7 +427,7 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	case SPI_IOC_WR_LSB_FIRST:
-		retval = __get_user(tmp, (__u8 __user *)arg);
+		retval = get_user(tmp, (__u8 __user *)arg);
 		if (retval == 0) {
 			u32	save = spi->mode;
 
@@ -462,7 +444,7 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	case SPI_IOC_WR_BITS_PER_WORD:
-		retval = __get_user(tmp, (__u8 __user *)arg);
+		retval = get_user(tmp, (__u8 __user *)arg);
 		if (retval == 0) {
 			u8	save = spi->bits_per_word;
 
@@ -475,7 +457,7 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	case SPI_IOC_WR_MAX_SPEED_HZ:
-		retval = __get_user(tmp, (__u32 __user *)arg);
+		retval = get_user(tmp, (__u32 __user *)arg);
 		if (retval == 0) {
 			u32	save = spi->max_speed_hz;
 
@@ -525,8 +507,6 @@ spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
 	struct spi_ioc_transfer		*ioc;
 
 	u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
-	if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd)))
-		return -EFAULT;
 
 	/* guard against device removal before, or while,
 	 * we issue this ioctl.