From patchwork Wed May 20 07:03:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Almeida X-Patchwork-Id: 11559467 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 92F6B60D for ; Wed, 20 May 2020 07:04:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7425F20884 for ; Wed, 20 May 2020 07:04:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="p/lyKf/G" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbgETHEF (ORCPT ); Wed, 20 May 2020 03:04:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726714AbgETHED (ORCPT ); Wed, 20 May 2020 03:04:03 -0400 Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98AC1C061A0E; Wed, 20 May 2020 00:04:03 -0700 (PDT) Received: by mail-qk1-x72e.google.com with SMTP id i14so2532425qka.10; Wed, 20 May 2020 00:04:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=B45hogykBorpQm91C/FLYv1RqOa4QVoaffagDFE18Qs=; b=p/lyKf/Gdc+2iVQRO4CL5QgtxU90uvVYQTbXEtDJ+qJkmEBdaHBzZtg3EYouUtnqDv KX2OGCe9H50xiuG+xKF1wH7SqNELgTrbP2RYwvBz02CJFpY0vjJWF8oQqAB9I2H1wOlP 7X4ha9uaAyBX4eTHzApnO71O8pp+lba37+gc7wCW2szngDosTNGKkLGYrYMMYKZCNFLF S61Vyck5CVkVVEFJUuqJog26l/S2luLWpWPps1mtevZcnEG1AuGGVZ26PtNzgU553sqM RXywEVAS29Cfen0buKuwimEi7TGKP9xThToFZIYl3QXzeA9jfGwt1n2p7dca09hqpFDk cMHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=B45hogykBorpQm91C/FLYv1RqOa4QVoaffagDFE18Qs=; b=VWTx79N9XXNVY7oeFKXqt7M9Hi2opvrjfk+WAMLWgqBkoyezBmWZhv9FbYFlhru9A8 Fg5Lj6b+w24AG9c9Pjyx3dJUDWOXcUybtt5TqmyTQLfCO4tdeuSRsUVQSD8KOwBKQjt/ KyU3I92QekisimnEPGTIUOwLS4kgEfHEJM678vbu3vLN6axvUyy7QvPYmI86bLq2zsRH 4HlP5rmTAZ/KIA+A3cJfjdsM8T0XvVW9Vfcu63o8K93vVsx07K8gRgnO8fjjXXiKgH9K kBJO6WYCsU+w/yWTIh3flWu+iM0T0ZK5EvFfm7aOf4gbZn1dycGb3m5UHdwmFuSeS592 dL3g== X-Gm-Message-State: AOAM530jRN4MnDEl+9b/SVy6w3/HJIbY6MB8/OSi8rI6N+CgTQI1VUIb BeqnMitBCHED4q3+huuT9Gk= X-Google-Smtp-Source: ABdhPJx/lvWZHJwUMrKvIsNzP2GHGpkP7hzzOjMX5m5YuAIDHeHmG50gFRYcLQ/uu8woz2yFi3/vhQ== X-Received: by 2002:a37:6e42:: with SMTP id j63mr3198105qkc.495.1589958242727; Wed, 20 May 2020 00:04:02 -0700 (PDT) Received: from localhost.localdomain ([2804:14d:72b1:8920:a2ce:f815:f14d:bfac]) by smtp.gmail.com with ESMTPSA id i23sm1598893qke.65.2020.05.20.00.03.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2020 00:04:01 -0700 (PDT) From: "Daniel W. S. Almeida" X-Google-Original-From: Daniel W. S. Almeida To: mchehab+huawei@kernel.org, sean@mess.org, kstewart@linuxfoundation.org, allison@lohutok.net, tglx@linutronix.de Cc: "Daniel W. S. Almeida" , linux-media@vger.kernel.org, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [RFC, WIP, v6 05/10] media: vidtv: add wrappers for memcpy and memset Date: Wed, 20 May 2020 04:03:29 -0300 Message-Id: <20200520070334.1778751-6-dwlsalmeida@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200520070334.1778751-1-dwlsalmeida@gmail.com> References: <20200520070334.1778751-1-dwlsalmeida@gmail.com> MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: "Daniel W. S. Almeida" A lot of code in this driver is for serializing structures. This is error prone. Therefore, prevent buffer overflows by wrapping memcpy and memset, comparing the requested length against the buffer size. Signed-off-by: Daniel W. S. Almeida --- .../media/test-drivers/vidtv/vidtv_common.c | 86 +++++++++++++++++++ .../media/test-drivers/vidtv/vidtv_common.h | 27 ++++++ 2 files changed, 113 insertions(+) create mode 100644 drivers/media/test-drivers/vidtv/vidtv_common.c create mode 100644 drivers/media/test-drivers/vidtv/vidtv_common.h diff --git a/drivers/media/test-drivers/vidtv/vidtv_common.c b/drivers/media/test-drivers/vidtv/vidtv_common.c new file mode 100644 index 0000000000000..6810212087c17 --- /dev/null +++ b/drivers/media/test-drivers/vidtv/vidtv_common.c @@ -0,0 +1,86 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The Virtual DVB test driver serves as a reference DVB driver and helps + * validate the existing APIs in the media subsystem. It can also aid + * developers working on userspace applications. + * + * Written by Daniel W. S. Almeida + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__ + +#include +#include +#include +#include + +#include "vidtv_common.h" + +/** + * vidtv_memcpy() - wrapper routine to be used by MPEG-TS + * generator, in order to avoid going past the + * output buffer. + * @to: Starting element to where a MPEG-TS packet will + * be copied. + * @to_offset: Starting position of the @to buffer to be filled. + * @to_size: Size of the @to buffer. + * @from: Starting element of the buffer to be copied. + * @len: Number of elements to be copy from @from buffer + * into @to+ @to_offset buffer. + * + * Note: + * Real digital TV demod drivers should not have memcpy + * wrappers. We use it here because emulating MPEG-TS + * generation at kernelspace requires some extra care. + * + * Return: + * Returns the number of bytes written + */ +u32 vidtv_memcpy(void *to, + size_t to_offset, + size_t to_size, + const void *from, + size_t len) +{ + if (unlikely(to_offset + len > to_size)) { + pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size\n"); + return 0; + } + + memcpy(to + to_offset, from, len); + return len; +} + +/** + * vidtv_memset() - wrapper routine to be used by MPEG-TS + * generator, in order to avoid going past the + * output buffer. + * @to: Starting element to set + * @to_offset: Starting position of the @to buffer to be filled. + * @to_size: Size of the @to buffer. + * @from: Starting element of the buffer to be copied. + * @ten: Number of elements to be copy from @from buffer + * into @to+ @to_offset buffer. + * + * Note: + * Real digital TV demod drivers should not have memset + * wrappers. We use it here because emulating MPEG-TS + * generation at kernelspace requires some extra care. + * + * Return: + * Returns the number of bytes written + */ +u32 vidtv_memset(void *to, + size_t to_offset, + size_t to_size, + const int c, + size_t len) +{ + if (unlikely(to_offset + len > to_size)) { + pr_err_ratelimited("overflow detected, skipping. Try increasing the buffer size\n"); + return 0; + } + + memset(to + to_offset, c, len); + return len; +} diff --git a/drivers/media/test-drivers/vidtv/vidtv_common.h b/drivers/media/test-drivers/vidtv/vidtv_common.h new file mode 100644 index 0000000000000..a3cb303cc7423 --- /dev/null +++ b/drivers/media/test-drivers/vidtv/vidtv_common.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * The Virtual DVB test driver serves as a reference DVB driver and helps + * validate the existing APIs in the media subsystem. It can also aid + * developers working on userspace applications. + * + * Written by Daniel W. S. Almeida + */ + +#ifndef VIDTV_COMMON_H +#define VIDTV_COMMON_H + +#include + +u32 vidtv_memcpy(void *to, + size_t to_offset, + size_t to_size, + const void *from, + size_t len); + +u32 vidtv_memset(void *to, + size_t to_offset, + size_t to_size, + int c, + size_t len); + +#endif // VIDTV_COMMON_H