[PATCH AUTOSEL 4.19] i2c: dev: copy userspace array safely

[Sasha Levin]

From: Philipp Stanner <pstanner@xxxxxxxxxx>

[ Upstream commit cc9c54232f04aef3a5d7f64a0ece7df00f1aaa3d ]

i2c-dev.c utilizes memdup_user() to copy a userspace array. This is done
without an overflow check.

Use the new wrapper memdup_array_user() to copy the array more safely.

Suggested-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/i2c/i2c-dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 140dd074fdee5..e4c8d029d73c0 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -459,8 +459,8 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
 			return -EINVAL;
 
-		rdwr_pa = memdup_user(rdwr_arg.msgs,
-				      rdwr_arg.nmsgs * sizeof(struct i2c_msg));
+		rdwr_pa = memdup_array_user(rdwr_arg.msgs,
+					    rdwr_arg.nmsgs, sizeof(struct i2c_msg));
 		if (IS_ERR(rdwr_pa))
 			return PTR_ERR(rdwr_pa);
 
-- 
2.42.0