From 381583845d19cb4bd21c8193449385f3fefa9caf Mon Sep 17 00:00:00 2001 From: Harshit Mogalapalli Date: Wed, 8 Jun 2022 05:26:09 -0700 Subject: [PATCH] HID: cp2112: prevent a buffer overflow in cp2112_xfer() Smatch warnings: drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'data->block[1]' too small (33 vs 255) drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'buf' too small (64 vs 255) The 'read_length' variable is provided by 'data->block[0]' which comes from user and it(read_length) can take a value between 0-255. Add an upper bound to 'read_length' variable to prevent a buffer overflow in memcpy(). Fixes: 542134c0375b ("HID: cp2112: Fix I2C_BLOCK_DATA transactions") Signed-off-by: Harshit Mogalapalli Signed-off-by: Jiri Kosina --- drivers/hid/hid-cp2112.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index ece147d1a278..1e16b0fa310d 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -790,6 +790,11 @@ static int cp2112_xfer(struct i2c_adapter *adap, u16 addr, data->word = le16_to_cpup((__le16 *)buf); break; case I2C_SMBUS_I2C_BLOCK_DATA: + if (read_length > I2C_SMBUS_BLOCK_MAX) { + ret = -EINVAL; + goto power_normal; + } + memcpy(data->block + 1, buf, read_length); break; case I2C_SMBUS_BLOCK_DATA: -- 2.11.0