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 1C0BE4F5E0; Wed, 20 May 2026 18:00:23 +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=1779300025; cv=none; b=X/gFdElxLfF/YBtRpv8Gm+N0m87bavaqSE8cI6Lnn0RzQDG/JgtWCOGF8+uWAnG7gL4Jguhn0OANvZHIWy3dnK5PrzPswR1wxybxuZUaG8Lvt1Jsnxlk4ggqMR9giDkrYvEtI4MF5r/8A4Ce6kQPYI9lLU1H4g/aYDjQmoPJWJE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779300025; c=relaxed/simple; bh=FnIVcMrRwV/T7iYnyggMw6y32QxSfo5OllZVpqXR3Es=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d0SCQncL5XEcFhBjDRNUvNijInvI7gHV9+aw24xgdENXfUbPh46NngTjMszGCY37Ki6u4/JWTsq7FyJJJ/myBmJDC0QxCtztVNhBy3rhBsxrc2YD/+aoZj0urAkX/Vp3r2Jz+qDk3p96rb+p1FmAB9gT5O6511FqxAVnwDu5Ob4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vZqeDl5X; 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="vZqeDl5X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D2171F000E9; Wed, 20 May 2026 18:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779300023; bh=dGsfmboJt/1zFFAeOBRilNY6U7JLUafvEmYnkrK6uAQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vZqeDl5XnLiXvJ0Os+LgjA0L0M624eLCrdbD1UjPWRGgtjhM9TEs7QFrCsSStaFMP XTYFrmI34xwocTD68d52gxmKRGhdNyefLnWAV54XGn4uyiNUd/1i+jKGl5Y+WoHtlq MF4oRLTIqUvuerL/wNXY3CXbydQ8SuXas/g75MaM= 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 6.12 019/666] debugfs: check for NULL pointer in debugfs_create_str() Date: Wed, 20 May 2026 18:13:50 +0200 Message-ID: <20260520162111.645118920@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162111.222830634@linuxfoundation.org> References: <20260520162111.222830634@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-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 67299e8b734ed..d3ffd954d6f94 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1071,7 +1071,7 @@ 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 @@ -1080,6 +1080,9 @@ 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