linux-kernel - [PATCH] overlayfs: fix uninitialized pointers with free attr

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: <20251105-aheev-uninitialized-free-attr-overlayfs-v1-1-6ae4624655db@gmail.com>
Date: Wed, 05 Nov 2025 20:03:44 +0530
From: Ally Heev <allyheev@...il.com>
To: Miklos Szeredi <miklos@...redi.hu>, Amir Goldstein <amir73il@...il.com>
Cc: linux-unionfs@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Dan Carpenter <dan.carpenter@...aro.org>, Ally Heev <allyheev@...il.com>
Subject: [PATCH] overlayfs: fix uninitialized pointers with free attr

Uninitialized pointers with `__free` attribute can cause undefined
behaviour as the memory assigned(randomly) to the pointer is freed
automatically when the pointer goes out of scope

overlayfs doesn't have any bugs related to this as of now, but
it is better to initialize and assign pointers with `__free` attr
in one statement to ensure proper scope-based cleanup

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/
Signed-off-by: Ally Heev <allyheev@...il.com>
---
 fs/overlayfs/params.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 63b7346c5ee1c127a9c33b12c3704aa035ff88cf..56d5906e1e41ae6581911cbd269d0fb085db4516 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -448,10 +448,9 @@ static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param,
 		err = ovl_do_parse_layer(fc, param->string, &layer_path, layer);
 		break;
 	case fs_value_is_file: {
-		char *buf __free(kfree);
 		char *layer_name;
+		char *buf __free(kfree) = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
 
-		buf = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
 		if (!buf)
 			return -ENOMEM;
 

---
base-commit: c9cfc122f03711a5124b4aafab3211cf4d35a2ac
change-id: 20251105-aheev-uninitialized-free-attr-overlayfs-6873964429e0

Best regards,
-- 
Ally Heev <allyheev@...il.com>