From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD29C3D7D7E; Wed, 20 May 2026 16:26:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779294419; cv=none; b=rMU394rQcwAvOvOFhlSGQspF7Etr3CoGhzLJ1GFFb77CUzMKLorqCyzCWl2a1gmrLrLnYHF3d97D0sJEgLA7w/YBIEUFxl6Mefy771Y5jIuNCSFXkgmS/8EzjwH+txbo0bIyVkTcTmCv2/jUtPfnc6Kd0T5g/pBYqO1bpc2OowY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779294419; c=relaxed/simple; bh=fy/C/QT3DjylKkWlXGvzBvU7tNeAG2wt+pOWRn2hi5I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JY/M0IX95hcacrXXpijt1uvmXP2p8pQcAy4HfdSzaCjin0MjvF0bu+edKIUUPCWu8jfRgBdi0I4I6dg1dPzdr24AD7bw1vmt3DzfL+AXCJLYeAE8iQOgax0kTpycX5yzQF6JLV2+Gs1pSyWlx9ABishJ2FFz7PNStRiPTyMvKOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ipoRWg3W; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ipoRWg3W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C21D1F000E9; Wed, 20 May 2026 16:26:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779294418; bh=PNqPWyqQvhsqFNaOQ7BIvTz7JQg+6NurpsRo+JNnhE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ipoRWg3WqOC7eoKqGZ818LI8oVSqkuoEjO42rwlyYx8ThAzxA41SUjc+n6CKlRB9g N/mZBkASF1C1unVSQHHlHcEx5p7RN7qpE2/JwtGi7Qf+FybKZMMtHAt9++9hUY3cyY 3n7MaPwyzA8D0qLOg8VvwiRyCb/axsIRu/uuZBy0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, yangshiguang , Gui-Dong Han , Sasha Levin Subject: [PATCH 7.0 0031/1146] debugfs: check for NULL pointer in debugfs_create_str() Date: Wed, 20 May 2026 18:04:41 +0200 Message-ID: <20260520162149.088271124@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162148.390695140@linuxfoundation.org> References: <20260520162148.390695140@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gui-Dong Han [ Upstream commit 31de83980d3764d784f79ff1bc93c42b324f4013 ] Passing a NULL pointer to debugfs_create_str() leads to a NULL pointer dereference when the debugfs file is read. Following upstream discussions, forbid the creation of debugfs string files with NULL pointers. Add a WARN_ON() to expose offending callers and return early. Fixes: 9af0440ec86e ("debugfs: Implement debugfs_create_str()") Reported-by: yangshiguang Closes: https://lore.kernel.org/lkml/2025122221-gag-malt-75ba@gregkh/ Suggested-by: Greg Kroah-Hartman Signed-off-by: Gui-Dong Han Link: https://patch.msgid.link/20260323085930.88894-2-hanguidong02@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- fs/debugfs/file.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 3376ab6a519d1..a941d73251b06 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1127,7 +1127,7 @@ static const struct file_operations fops_str_wo = { * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write - * from. + * from. This pointer and the string it points to must not be %NULL. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so @@ -1136,6 +1136,9 @@ static const struct file_operations fops_str_wo = { void debugfs_create_str(const char *name, umode_t mode, struct dentry *parent, char **value) { + if (WARN_ON(!value || !*value)) + return; + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str, &fops_str_ro, &fops_str_wo); } -- 2.53.0