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i2c: dev: copy userspace array safely

PATCH New Sasha Levin 1 participant 1 message Nov 12, 2023

Subsystems (2)
Stable branch I2C subsystem host drivers
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Sasha Levin

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PATCH 1/1 i2c: dev: copy userspace array safely

From: Philipp Stanner <[email protected]>

[ 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 <[email protected]>
Signed-off-by Philipp Stanner <[email protected]>
Signed-off-by Wolfram Sang <[email protected]>
Signed-off-by Sasha Levin <[email protected]>
---
 drivers/i2c/i2c-dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/i2c/i2c-dev.c +2 -2
index a01b59e3599b5..7d337380a05d9 100644
@@ -450,8 +450,8 @@ 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);
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2.42.0