From patchwork Mon Dec 16 10:45:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 13909528 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) (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 876C2203D42 for ; Mon, 16 Dec 2024 10:45:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.181.97.72 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734345935; cv=none; b=X2/uFJVG920e2IFwrgO1pkcYEAd+VqjGL64DY7XmU/oi6dT8jm2g43Z04wWpVNx2VwhRy3FaAEO1aVDYkhfT7IiJJT2RocufdKecuGWrs6J67WFIcBbwdJGYCIm1cwKcPwUzS2XWFJUmAhTfCEc759IhgfrM4NF/IxDDkI+b1uU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734345935; c=relaxed/simple; bh=FiUPkIE/sDWZPVHArm16IayTrZ7JdqAK/P7UJ9pzxbU=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=Lhd5SPK/BEDrTilEn35GQJWUXMndJqfJat1PCtIC8djxxDMcEoq/GfRBu0qNuTr9KvtypU9ldz+ueZgILlcCX/YN7wZZ0ami1Les6VGds0rwdGDKDtyn06svhKQG70aaXNBvMQzAYuLYxC6eCMWyaH1ouKWLO94nUKFO7FcEOS0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp; arc=none smtp.client-ip=202.181.97.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp Received: from www262.sakura.ne.jp (localhost [127.0.0.1]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 4BGAj7vX060266; Mon, 16 Dec 2024 19:45:07 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 4BGAj7ks060262 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Mon, 16 Dec 2024 19:45:07 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <57f7253d-a55e-420a-b1b1-f572a0ab13f2@I-love.SAKURA.ne.jp> Date: Mon, 16 Dec 2024 19:45:06 +0900 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH] tomoyo: don't emit warning in tomoyo_write_control() To: syzbot , jmorris@namei.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, paul@paul-moore.com, serge@hallyn.com, syzkaller-bugs@googlegroups.com, takedakn@nttdata.co.jp, Leo Stone References: <675f4ea7.050a0220.37aaf.0105.GAE@google.com> Content-Language: en-US From: Tetsuo Handa In-Reply-To: <675f4ea7.050a0220.37aaf.0105.GAE@google.com> X-Anti-Virus-Server: fsav404.rs.sakura.ne.jp X-Virus-Status: clean syzbot is reporting too large allocation warning at tomoyo_write_control(), for one can write a very very long line without new line character. To fix this warning, I use __GFP_NOWARN rather than checking for KMALLOC_MAX_SIZE, for practically a valid line should be always shorter than 32KB where the "too small to fail" memory-allocation rule applies. One might try to write a valid line that is longer than 32KB, but such request will likely fail with -ENOMEM. Therefore, I feel that separately returning -EINVAL when a line is longer than KMALLOC_MAX_SIZE is redundant. There is no need to distinguish over-32KB and over-KMALLOC_MAX_SIZE. Reported-by: syzbot+7536f77535e5210a5c76@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7536f77535e5210a5c76 Reported-by: Leo Stone Closes: https://lkml.kernel.org/r/20241216021459.178759-2-leocstone@gmail.com Signed-off-by: Tetsuo Handa --- security/tomoyo/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c index 5c7b059a332a..972664962e8f 100644 --- a/security/tomoyo/common.c +++ b/security/tomoyo/common.c @@ -2665,7 +2665,7 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head, if (head->w.avail >= head->writebuf_size - 1) { const int len = head->writebuf_size * 2; - char *cp = kzalloc(len, GFP_NOFS); + char *cp = kzalloc(len, GFP_NOFS | __GFP_NOWARN); if (!cp) { error = -ENOMEM;