This is a note to let you know that I've just added the patch titled HID: mcp2221: prevent a buffer overflow in mcp_smbus_write() to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hid-mcp2221-prevent-a-buffer-overflow-in-mcp_smbus_w.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f2203d000ed1915fdbdc173b2e9fd82b7bdd7170 Author: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx> Date: Mon Jun 20 09:28:24 2022 -0700 HID: mcp2221: prevent a buffer overflow in mcp_smbus_write() [ Upstream commit 62ac2473553a00229e67bdf3cb023b62cf7f5a9a ] 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: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index 4211b9839209..de52e9f7bb8c 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/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; }