diff options
| author | Florian Pradines <florian.pradines@gmail.com> | 2026-05-09 09:45:17 +0000 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.com> | 2026-05-12 17:48:16 +0200 |
| commit | f097d246677b03db814c5862f368cea341b76a00 (patch) | |
| tree | 0c99ca034b43977c21004cdd662f93cdd5d530bb | |
| parent | 5f90dcfa8dc32a488581b78e575cdd7808ba5c78 (diff) | |
HID: mcp2221: fix OOB write in mcp2221_raw_event()
mcp2221_raw_event() copies device-supplied data into mcp->rxbuf at
offset rxbuf_idx without checking that the copy fits within the
destination buffer. A device responding with up to 60 bytes to a
small I2C/SMBus read can overflow the buffer.
Add a rxbuf_size field to struct mcp2221, set it alongside rxbuf in
mcp_i2c_smbus_read(), and check rxbuf_idx + data[3] <= rxbuf_size
before the memcpy.
Reported-by: Benoît Sevens <bsevens@google.com>
Signed-off-by: Florian Pradines <florian.pradines@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
| -rw-r--r-- | drivers/hid/hid-mcp2221.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index be80970ab48e..e4ddd8e9293b 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -128,6 +128,7 @@ struct mcp2221 { u8 *rxbuf; u8 txbuf[64]; int rxbuf_idx; + int rxbuf_size; int status; u8 cur_i2c_clk_div; struct gpio_chip *gc; @@ -330,12 +331,14 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, mcp->txbuf[3] = (u8)(msg->addr << 1); total_len = msg->len; mcp->rxbuf = msg->buf; + mcp->rxbuf_size = msg->len; } else { mcp->txbuf[1] = smbus_len; mcp->txbuf[2] = 0; mcp->txbuf[3] = (u8)(smbus_addr << 1); total_len = smbus_len; mcp->rxbuf = smbus_buf; + mcp->rxbuf_size = smbus_len; } ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4); @@ -919,6 +922,10 @@ static int mcp2221_raw_event(struct hid_device *hdev, mcp->status = -EINVAL; break; } + if (mcp->rxbuf_idx + data[3] > mcp->rxbuf_size) { + mcp->status = -EINVAL; + break; + } buf = mcp->rxbuf; memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]); mcp->rxbuf_idx = mcp->rxbuf_idx + data[3]; |