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Sat, 15 Nov 2025 05:41:50 -0800 (PST) Received: from aheev.home ([106.215.173.137]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-bc36e8a58cfsm7410316a12.10.2025.11.15.05.41.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 15 Nov 2025 05:41:49 -0800 (PST) From: Ally Heev Date: Sat, 15 Nov 2025 19:11:27 +0530 Subject: [PATCH v2] overlayfs: fix uninitialized pointers with free attribute Precedence: bulk X-Mailing-List: linux-unionfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251115-aheev-uninitialized-free-attr-overlayfs-v2-1-815a48767340@gmail.com> X-B4-Tracking: v=1; b=H4sIAAaDGGkC/5XNQQ7CIBCF4as0rB1TENC68h6mC2yn7SQtGEBib bi72Bu4/N/ifRsL6AkDu1Yb85gokLMlxKFi3WTsiEB9aSZqoTivFZgJMcHLkqVIZqYP9jB4RDA xenAJ/WzWIYC+nE+NllI0WLPy9vQ40HuX7m3piUJ0ft3hxH/r/0biwEEblFpIrVT/uI2LofnYu YW1Oecv1O//SN4AAAA= X-Change-ID: 20251105-aheev-uninitialized-free-attr-overlayfs-6873964429e0 To: Miklos Szeredi , Amir Goldstein , Christian Brauner Cc: linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org, Dan Carpenter , Ally Heev X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1625; i=allyheev@gmail.com; h=from:subject:message-id; bh=2g+Ig9rajCSJQdPS5HN+sWyz1uVJcolY62QNF/qsOF8=; b=owGbwMvMwCU2zXbRFfvr1TKMp9WSGDIlmnlW5N+xmXHh+X1rZpXV3gvr3j4qF7h3++fHJ2rMX /bmTpt3qKOUhUGMi0FWTJGFUVTKT2+T1IS4w0nfYOawMoEMYeDiFICJ/I5g+MP76c3TPYszdG9E Vb3v/VesmcP6xWjVlriPc+YHp1+KereOkWFfuM22H9MiD3g5/353cbY88471n07n5Jzzr8j4ZS0 WM4MDAA== X-Developer-Key: i=allyheev@gmail.com; a=openpgp; fpr=01151A4E2EB21A905EC362F6963DA2D43FD77B1C Uninitialized pointers with `__free` attribute can cause undefined behavior 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` attribute in one statement to ensure proper scope-based cleanup Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/ Acked-by: Amir Goldstein Signed-off-by: Ally Heev --- Changes in v2: - moved the variable initialization to the top - Link to v1: https://lore.kernel.org/r/20251105-aheev-uninitialized-free-attr-overlayfs-v1-1-6ae4624655db@gmail.com --- fs/overlayfs/params.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 63b7346c5ee1c127a9c33b12c3704aa035ff88cf..37086f73ac3ecfcd1c09ae6eccbb69723006e031 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -448,7 +448,7 @@ 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 *buf __free(kfree) = NULL; char *layer_name; buf = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT); --- base-commit: c9cfc122f03711a5124b4aafab3211cf4d35a2ac change-id: 20251105-aheev-uninitialized-free-attr-overlayfs-6873964429e0 Best regards, -- Ally Heev