From patchwork Wed Dec 13 16:42:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lee Jones X-Patchwork-Id: 754307 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D550D2FC42 for ; Wed, 13 Dec 2023 16:43:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="syOCzR1p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E5E0C433C8; Wed, 13 Dec 2023 16:43:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702485787; bh=9MqdC0Lzr8nJH/eweGgenOuSKTiqYwlElEoxJCh++2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=syOCzR1pFzH6D78Dms52k+7u8KamuzCVKnFQiO5Xo26CVrAFAO2+yMZ+w38Uo7IH3 Nl8bBxSJkTZ7cXOnuEhB0qQRuqJCUwul3a+s68hHqAVWntZ7ty0z2vPUgkM8YzyX/p 3+segpEX4C+XG5uJNn6EVnR2s4jWMjGl2mUPfLLr61dUw1idHZcHnCML4f1sW8Z9MB +jRGViIAwsHHD4PQs297yiEESHK7GKem8ZDn6hs6Fnyw79k02glVgxON0VgLIFlUSq En4wZ6/hxapsnOQOnlVhNfEvp6/7D+9nlZrxzfEbApLtlKdHCkAIgW8pDA69nX2za0 +hEiemazLugsw== From: Lee Jones To: lee@kernel.org, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Cristian Birsan , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea , linux-arm-kernel@lists.infradead.org Subject: [PATCH 05/12] usb: gadget: udc: atmel: Replace snprintf() with the safer scnprintf() variant Date: Wed, 13 Dec 2023 16:42:34 +0000 Message-ID: <20231213164246.1021885-6-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> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 Cc: Cristian Birsan Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Lee Jones --- drivers/usb/gadget/udc/atmel_usba_udc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c index 02b1bef5e22e2..b76885d78e8a7 100644 --- a/drivers/usb/gadget/udc/atmel_usba_udc.c +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c @@ -94,7 +94,7 @@ static ssize_t queue_dbg_read(struct file *file, char __user *buf, inode_lock(file_inode(file)); list_for_each_entry_safe(req, tmp_req, queue, queue) { - len = snprintf(tmpbuf, sizeof(tmpbuf), + len = scnprintf(tmpbuf, sizeof(tmpbuf), "%8p %08x %c%c%c %5d %c%c%c\n", req->req.buf, req->req.length, req->req.no_interrupt ? 'i' : 'I', @@ -104,7 +104,6 @@ static ssize_t queue_dbg_read(struct file *file, char __user *buf, req->submitted ? 'F' : 'f', req->using_dma ? 'D' : 'd', req->last_transaction ? 'L' : 'l'); - len = min(len, sizeof(tmpbuf)); if (len > nbytes) break;