linux-kernel - [PATCH] media: ipu3: don't use recursion at the Kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <cf020b6a04b3a9d7f08750927b1d100f63ff4689.1638445455.git.mchehab+huawei@kernel.org>
Date:   Thu,  2 Dec 2021 12:44:26 +0100
From:   Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:     Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Bingbu Cao <bingbu.cao@...el.com>,
        Dan Scally <djrscally@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tianshu Qiu <tian.shu.qiu@...el.com>,
        Yong Zhi <yong.zhi@...el.com>, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: [PATCH] media: ipu3: don't use recursion at the Kernel

The Kernel stack is too small. Doing recursions there is a very
bad idea, as, if something gets wrong, it could lead to data
corruption. So, re-implement cio2_check_fwnode_graph() to avoid
recursion.

Compile-tested only.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
---
 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
index 356ea966cf8d..8e4f250a8b56 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
@@ -1691,16 +1691,15 @@ static int cio2_check_fwnode_graph(struct fwnode_handle *fwnode)
 {
 	struct fwnode_handle *endpoint;
 
-	if (IS_ERR_OR_NULL(fwnode))
-		return -EINVAL;
-
-	endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
-	if (endpoint) {
-		fwnode_handle_put(endpoint);
-		return 0;
+	while (!IS_ERR_OR_NULL(fwnode)) {
+		endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
+		if (endpoint) {
+			fwnode_handle_put(endpoint);
+			return 0;
+		}
+		fwnode = fwnode->secondary;
 	}
-
-	return cio2_check_fwnode_graph(fwnode->secondary);
+	return -EINVAL;
 }
 
 /**************** PCI interface ****************/
-- 
2.33.1