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The driver failed to check if the total incoming data length fits within the originally allocated buffer `mcp->rxbuf`. Fix this by introducing `rxbuf_len` to `struct mcp2221` to keep track of the allocated buffer size. Initialize it in `mcp_i2c_smbus_read()` and `mcp_smbus_xfer()`, and ensure the copied data length combined with the current index does not exceed this length in `mcp2221_raw_event()`. Signed-off-by: Beno=C3=AEt Sevens --- drivers/hid/hid-mcp2221.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index ef3b5c77c38e..744561e65079 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -119,6 +119,7 @@ struct mcp2221 { struct completion wait_in_report; struct delayed_work init_work; u8 *rxbuf; + int rxbuf_len; u8 txbuf[64]; int rxbuf_idx; int status; @@ -323,12 +324,14 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, mcp->txbuf[3] =3D (u8)(msg->addr << 1); total_len =3D msg->len; mcp->rxbuf =3D msg->buf; + mcp->rxbuf_len =3D msg->len; } else { mcp->txbuf[1] =3D smbus_len; mcp->txbuf[2] =3D 0; mcp->txbuf[3] =3D (u8)(smbus_addr << 1); total_len =3D smbus_len; mcp->rxbuf =3D smbus_buf; + mcp->rxbuf_len =3D smbus_len; } =20 ret =3D mcp_send_data_req_status(mcp, mcp->txbuf, 4); @@ -538,6 +541,7 @@ static int mcp_smbus_xfer(struct i2c_adapter *adapter, = u16 addr, =20 mcp->rxbuf_idx =3D 0; mcp->rxbuf =3D data->block; + mcp->rxbuf_len =3D sizeof(data->block); mcp->txbuf[0] =3D MCP2221_I2C_GET_DATA; ret =3D mcp_send_data_req_status(mcp, mcp->txbuf, 1); if (ret) @@ -561,6 +565,7 @@ static int mcp_smbus_xfer(struct i2c_adapter *adapter, = u16 addr, =20 mcp->rxbuf_idx =3D 0; mcp->rxbuf =3D data->block; + mcp->rxbuf_len =3D sizeof(data->block); mcp->txbuf[0] =3D MCP2221_I2C_GET_DATA; ret =3D mcp_send_data_req_status(mcp, mcp->txbuf, 1); if (ret) @@ -908,7 +913,9 @@ static int mcp2221_raw_event(struct hid_device *hdev, } if (data[2] =3D=3D MCP2221_I2C_READ_COMPL || data[2] =3D=3D MCP2221_I2C_READ_PARTIAL) { - if (!mcp->rxbuf || mcp->rxbuf_idx < 0 || data[3] > 60) { + if (!mcp->rxbuf || mcp->rxbuf_idx < 0 || + data[3] > 60 || + mcp->rxbuf_idx + data[3] > mcp->rxbuf_len) { mcp->status =3D -EINVAL; break; } --=20 2.54.0.rc0.605.g598a273b03-goog