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Commit 519ff31a authored by Harshit Mogalapalli's avatar Harshit Mogalapalli Committed by Greg Kroah-Hartman
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HID: cp2112: prevent a buffer overflow in cp2112_xfer() 



[ Upstream commit 381583845d19cb4bd21c8193449385f3fefa9caf ]

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: 542134c0 ("HID: cp2112: Fix I2C_BLOCK_DATA transactions")
Signed-off-by: default avatarHarshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 1367f4a3

drivers/hid/hid-cp2112.c

+5 −0
Original line number Diff line number Diff line
@@ -787,6 +787,11 @@ 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: