From nobody Fri Dec 19 05:42:23 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78D28C4332F for ; Wed, 13 Dec 2023 16:43:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233650AbjLMQnc (ORCPT ); Wed, 13 Dec 2023 11:43:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235406AbjLMQnI (ORCPT ); Wed, 13 Dec 2023 11:43:08 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DEA8A10C for ; Wed, 13 Dec 2023 08:43:14 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8150DC433C9; Wed, 13 Dec 2023 16:43:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702485794; bh=+jJ0AZEvag610YYMeIA2DZY9vRhnQ1MUWo6qd+Qzkcs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Plg/RkoEgxcb5oLFgT/r2pbwVa+OiOKfDqeFr23Y4XhEqyZ5uVBDN++Xkp9njtYA/ e/ZmXCZgAUTOyvm1+MRDRVjk/Goo8EXcyPKp/Z5Jq6vkTd7Z0kpFegYh/Cr9+MFWQC ExHTW5hlY3r+qo8ZKQSDl3P2AIFZRW2roFNhvsQBR8o6zm7rZPMr8nRhSijOrPYRQB jum+fusgZZy+M4y8zPPL3U6Btq5SJH2c8BRlGS5oiDRK4vX1rVhGb5qPcu+A+1FypL eGsgpAVmBSsoR8RBqoGoAYvcP7xcmaFTF+SCgp92suHe8vT62kPWYfSnmce8dWivHj 6fNgbUfjI7k1Q== From: Lee Jones To: lee@kernel.org, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: [PATCH 09/12] usb: mon_stat: Replace snprintf() with the safer scnprintf() variant Date: Wed, 13 Dec 2023 16:42:38 +0000 Message-ID: <20231213164246.1021885-10-lee@kernel.org> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog In-Reply-To: <20231213164246.1021885-1-lee@kernel.org> References: <20231213164246.1021885-1-lee@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There is a general misunderstanding amongst engineers that {v}snprintf() returns the length of the data *actually* encoded into the destination array. However, as per the C99 standard {v}snprintf() really returns the length of the data that *would have been* written if there were enough space for it. This misunderstanding has led to buffer-overruns in the past. It's generally considered safer to use the {v}scnprintf() variants in their place (or even sprintf() in simple cases). So let's do that. Link: https://lwn.net/Articles/69419/ Link: https://github.com/KSPP/linux/issues/105 Signed-off-by: Lee Jones --- drivers/usb/mon/mon_stat.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/usb/mon/mon_stat.c b/drivers/usb/mon/mon_stat.c index 98ab0cc473d67..3c23805ab1a44 100644 --- a/drivers/usb/mon/mon_stat.c +++ b/drivers/usb/mon/mon_stat.c @@ -35,9 +35,9 @@ static int mon_stat_open(struct inode *inode, struct file= *file) =20 mbus =3D inode->i_private; =20 - sp->slen =3D snprintf(sp->str, STAT_BUF_SIZE, - "nreaders %d events %u text_lost %u\n", - mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); + sp->slen =3D scnprintf(sp->str, STAT_BUF_SIZE, + "nreaders %d events %u text_lost %u\n", + mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost); =20 file->private_data =3D sp; return 0; --=20 2.43.0.472.g3155946c3a-goog