linux-kernel - [PATCH v2] regmap: debugfs: Free debugfs

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: <20220106175019.3116389-1-festevam@gmail.com>
Date:   Thu,  6 Jan 2022 14:50:19 -0300
From:   Fabio Estevam <festevam@...il.com>
To:     broonie@...nel.org
Cc:     matthias.schiffer@...tq-group.com, linux-kernel@...r.kernel.org,
        Fabio Estevam <festevam@...il.com>
Subject: [PATCH v2] regmap: debugfs: Free debugfs_name buffer after usage

The following error message is seen when booting an imx6q-sabresd:

debugfs: Directory 'dummy-iomuxc-gpr@...0000' with parent 'regmap' already present!

The reason for the duplicate name is that map->debugfs_name is never freed,
which can cause a directory to be created with the same name used in the
previous debugfs entry allocation.

Fix this problem by freeing map->debugfs_name and setting it to NULL
after its usage.

Signed-off-by: Fabio Estevam <festevam@...il.com>
---
Changes since v1:
- Avoid use after free (Mark).

 drivers/base/regmap/regmap-debugfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index ad684d37c2da..e1017ca65be0 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -605,6 +605,9 @@ void regmap_debugfs_init(struct regmap *map)
 
 	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 
+	kfree(map->debugfs_name);
+	map->debugfs_name = NULL;
+
 	debugfs_create_file("name", 0400, map->debugfs,
 			    map, &regmap_name_fops);
 
-- 
2.25.1