From e56aac6e5a25630645607b6856d4b2a17b2311a5 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@linaro.org>
Date: Mon, 11 Nov 2024 14:08:06 +0300
Subject: [PATCH] usb: typec: fix potential array underflow in
ucsi_ccg_sync_control()
The "command" variable can be controlled by the user via debugfs. The
worry is that if con_index is zero then "&uc->ucsi->connector[con_index
- 1]" would be an array underflow.
Fixes: 170a6726d0e2 ("usb: typec: ucsi: add support for separate DP altmode devices")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/c69ef0b3-61b0-4dde-98dd-97b97f81d912@stanley.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/typec/ucsi/ucsi_ccg.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
index ba58d11907bc5..ec813eb908a76 100644
--- a/drivers/usb/typec/ucsi/ucsi_ccg.c
+++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
@@ -642,6 +642,10 @@ static int ucsi_ccg_sync_control(struct ucsi *ucsi, u64 command)
uc->has_multiple_dp) {
con_index = (uc->last_cmd_sent >> 16) &
UCSI_CMD_CONNECTOR_MASK;
+ if (con_index == 0) {
+ ret = -EINVAL;
+ goto unlock;
+ }
con = &uc->ucsi->connector[con_index - 1];
ucsi_ccg_update_set_new_cam_cmd(uc, con, &command);
}
@@ -649,6 +653,7 @@ static int ucsi_ccg_sync_control(struct ucsi *ucsi, u64 command)
ret = ucsi_sync_control_common(ucsi, command);
pm_runtime_put_sync(uc->dev);
+unlock:
mutex_unlock(&uc->lock);
return ret;