HID: mcp2221: prevent a buffer overflow in mcp_smbus_write()

stable inclusion
from stable-v5.10.137
commit 66c8e816f2f2ca4a61b406503bd10bad1b35f72f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=66c8e816f2f2ca4a61b406503bd10bad1b35f72f

--------------------------------

[ Upstream commit 62ac2473 ]

Smatch Warning:
drivers/hid/hid-mcp2221.c:388 mcp_smbus_write() error: __memcpy()
'&mcp->txbuf[5]' too small (59 vs 255)
drivers/hid/hid-mcp2221.c:388 mcp_smbus_write() error: __memcpy() 'buf'
too small (34 vs 255)

The 'len' variable can take a value between 0-255 as it can come from
data->block[0] and it is user data. So add an bound check to prevent a
buffer overflow in memcpy().

Fixes: 67a95c21 ("HID: mcp2221: add usb to i2c-smbus host bridge")
Signed-off-by: NHarshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/hid/hid-mcp2221.c

@@ -385,6 +385,9 @@ static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
 		data_len = 7;
 		break;
 	default:
+		if (len > I2C_SMBUS_BLOCK_MAX)
+			return -EINVAL;
+
 		memcpy(&mcp->txbuf[5], buf, len);
 		data_len = len + 5;
 	}