[PATCH] Input: elan_i2c - validate firmware size before use

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Ensure that the firmware file is large enough to contain the expected
number of pages and the signature (which resides at the end of the
firmware blob) before accessing them to prevent potential out-of-bounds
reads.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/mouse/elan_i2c_core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
index fee1796da3d0..74f822cd8774 100644
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -645,6 +645,11 @@ static ssize_t elan_sysfs_update_fw(struct device *dev,
 		return error;
 	}
 
+	if (fw->size < data->fw_signature_address + sizeof(signature)) {
+		dev_err(dev, "firmware file too small\n");
+		return -EBADF;
+	}
+
 	/* Firmware file must match signature data */
 	fw_signature = &fw->data[data->fw_signature_address];
 	if (memcmp(fw_signature, signature, sizeof(signature)) != 0) {
-- 
2.54.0.545.g6539524ca2-goog


-- 
Dmitry