From patchwork Fri May 15 21:48:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Almeida X-Patchwork-Id: 63880 Received: from vger.kernel.org ([23.128.96.18]) by www.linuxtv.org with esmtp (Exim 4.92) (envelope-from ) id 1jZi9A-009h0i-Tl; Fri, 15 May 2020 21:45:37 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728032AbgEOVtD (ORCPT + 1 other); Fri, 15 May 2020 17:49:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726266AbgEOVtD (ORCPT ); Fri, 15 May 2020 17:49:03 -0400 Received: from mail-qt1-x842.google.com (mail-qt1-x842.google.com [IPv6:2607:f8b0:4864:20::842]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D05E5C061A0C; Fri, 15 May 2020 14:49:02 -0700 (PDT) Received: by mail-qt1-x842.google.com with SMTP id b1so3337778qtt.1; Fri, 15 May 2020 14:49:02 -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=llFN1b4IyM2NmP1m0ZO+FT2673CkYgwiHGyYGvoTCac=; b=V6JQzLS5IPik6GglApB4QLQr3Rk+BCjB8x+3A9tOoC3C3imphXlKmhUgrKAZxavmyx q4qe66XDQCBdVO1q8/ssUlVuQTgZ0rqGgiqsnhzlcFQIVnmY9UcSOI6+3qqKnBnqC/R4 I7ntrrH1h1SDo7BQj/GX9PHIgd6mhuNRmcAuUDW8hNoZh9/kBHRToYXUUqJ0Fgygx4/Z gRAzFld1GON9AOXJ0hUTLYG/3Oos5EwISVfPUPLP28SyY1ImelHdCawfXHLpBj0DMi1/ e65Kh79Nips7EtVciqldL3mrDRpB3lY5qtxDyBMwj0zH8/Wp2+PgBNi3fMEDiTvEvhf1 x2Kw== 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=llFN1b4IyM2NmP1m0ZO+FT2673CkYgwiHGyYGvoTCac=; b=dtaBPAsfB1+chCm0m8tM5n9RSuPN8d3er1dEvF9oVRtt0EkBpJ5gGB8ZTV+XuRhBua vZdo8nG32gywxu2KYYOoQjiC9ju8fwdlM7VS4hfyehSo4mVi5+fFGg0awu/99YjgSp9B Tii8EzBt4kzZt53ggxZDv7hGDZ4Wi7DcN6gfsE9hOXo6Ah819pwB4YnK96xc9u1Etj6+ 4tKeeM4LlBLrzHhztZdI96GIf5XeRbhGORHAs8e1JpXvByJ/SQTmmOLTepdGNshyayuD gZ3lU1APPeVy4364DMCknt5UCsPlsH6qkrIr0IP9lSxT+67xfDFqTCUbeWNy2+dZJyQp tp1A== X-Gm-Message-State: AOAM532KurXtYwMaHN8kyorfzkrS3EVPlnuPkrGJpXtMvRmGPsszajs9 5HrGL2y1NQI/BJJwJ/ZqXnM= X-Google-Smtp-Source: ABdhPJyK6pyDmQBPYu9OmmQLKHe4TfmPSRCircJ4ofbXp6a1jaBRckDdpXWQS4OLcC874uTz7KE1hA== X-Received: by 2002:ac8:51c5:: with SMTP id d5mr5794502qtn.232.1589579341933; Fri, 15 May 2020 14:49:01 -0700 (PDT) Received: from localhost.localdomain ([2804:18:700e:2692:8980:dd13:6be6:4050]) by smtp.gmail.com with ESMTPSA id m21sm2495019qkh.50.2020.05.15.14.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 May 2020 14:49:01 -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, v5 05/10] media: vidtv: add wrappers for memcpy and memset Date: Fri, 15 May 2020 18:48:10 -0300 Message-Id: <20200515214815.15514-6-dwlsalmeida@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200515214815.15514-1-dwlsalmeida@gmail.com> References: <20200515214815.15514-1-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 X-LSpam-Score: -2.5 (--) X-LSpam-Report: No, score=-2.5 required=5.0 tests=BAYES_00=-1.9,DKIM_SIGNED=0.1,DKIM_VALID=-0.1,DKIM_VALID_AU=-0.1,FREEMAIL_FORGED_FROMDOMAIN=0.001,FREEMAIL_FROM=0.001,HEADER_FROM_DIFFERENT_DOMAINS=0.5,MAILING_LIST_MULTI=-1 autolearn=ham autolearn_force=no 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..944f77625c12c --- /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