[PATCH v2 3/6] media: i2c: adv7604: Add range checks for chip info

[Ricardo Ribalda <ribalda@chromium.org>]

If the driver's chip information is invalid we can end up accessing an
invalid memory region.

This fixes the following false positive smatch errors:
drivers/media/i2c/adv7604.c:3672 adv76xx_probe() error: buffer overflow 'state->pads' 7 <= 4294967294
drivers/media/i2c/adv7604.c:3673 adv76xx_probe() error: buffer overflow 'state->pads' 7 <= u32max

Reviewed-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/i2c/adv7604.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
index 67116a4ef134..ae75982fb514 100644
--- a/drivers/media/i2c/adv7604.c
+++ b/drivers/media/i2c/adv7604.c
@@ -3668,6 +3668,12 @@ static int adv76xx_probe(struct i2c_client *client)
 
 	state->source_pad = state->info->num_dv_ports
 			  + (state->info->has_afe ? 2 : 0);
+	if (WARN_ON(state->source_pad >= ADV76XX_PAD_MAX)) {
+		err = -EINVAL;
+		v4l2_err(sd, "invalid chip info\n");
+		goto err_i2c;
+	}
+
 	for (i = 0; i < state->source_pad; ++i)
 		state->pads[i].flags = MEDIA_PAD_FL_SINK;
 	state->pads[state->source_pad].flags = MEDIA_PAD_FL_SOURCE;

-- 
2.54.0.545.g6539524ca2-goog