From patchwork Wed Jun 5 23:55:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas De Marchi X-Patchwork-Id: 10978123 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 05D471398 for ; Wed, 5 Jun 2019 23:55:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E8053287AD for ; Wed, 5 Jun 2019 23:55:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D850B286DB; Wed, 5 Jun 2019 23:55:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 704BD286DB for ; Wed, 5 Jun 2019 23:55:43 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 44A008926E; Wed, 5 Jun 2019 23:55:42 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 908DB8926E for ; Wed, 5 Jun 2019 23:55:41 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jun 2019 16:55:41 -0700 X-ExtLoop1: 1 Received: from ldmartin-desk.jf.intel.com ([10.24.8.250]) by orsmga005.jf.intel.com with ESMTP; 05 Jun 2019 16:55:40 -0700 From: Lucas De Marchi To: intel-gfx@lists.freedesktop.org Date: Wed, 5 Jun 2019 16:55:35 -0700 Message-Id: <20190605235535.17791-1-lucas.demarchi@intel.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/dmc: protect against reading random memory X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , Lucas De Marchi Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP While loading the DMC firmware we were double checking the headers made sense, but in no place we checked that we were actually reading memory we were supposed to. This could be wrong in case the firmware file is truncated or malformed. Before this patch: # ls -l /lib/firmware/i915/icl_dmc_ver1_07.bin -rw-r--r-- 1 root root 25716 Feb 1 12:26 icl_dmc_ver1_07.bin # truncate -s 25700 /lib/firmware/i915/icl_dmc_ver1_07.bin # modprobe i915 # dmesg| grep -i dmc [drm:intel_csr_ucode_init [i915]] Loading i915/icl_dmc_ver1_07.bin [drm] Finished loading DMC firmware i915/icl_dmc_ver1_07.bin (v1.7) i.e. it loads random data. Now it fails like below: [drm:intel_csr_ucode_init [i915]] Loading i915/icl_dmc_ver1_07.bin [drm:csr_load_work_fn [i915]] *ERROR* Truncated DMC firmware, rejecting. i915 0000:00:02.0: Failed to load DMC firmware i915/icl_dmc_ver1_07.bin. Disabling runtime power management. i915 0000:00:02.0: DMC firmware homepage: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/i915 Before reading any part of the firmware file, validate the input first. Fixes: eb805623d8b1 ("drm/i915/skl: Add support to load SKL CSR firmware.") Cc: stable@vger.kernel.org Signed-off-by: Lucas De Marchi Reviewed-by: Rodrigo Vivi --- This has been extracted from the bigger series https://patchwork.freedesktop.org/series/61016/ in a way that can be propagated to stable. drivers/gpu/drm/i915/intel_csr.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c index 4527b9662330..bf0eebd385b9 100644 --- a/drivers/gpu/drm/i915/intel_csr.c +++ b/drivers/gpu/drm/i915/intel_csr.c @@ -303,10 +303,17 @@ static u32 *parse_csr_fw(struct drm_i915_private *dev_priv, u32 dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes; u32 i; u32 *dmc_payload; + size_t fsize; if (!fw) return NULL; + fsize = sizeof(struct intel_css_header) + + sizeof(struct intel_package_header) + + sizeof(struct intel_dmc_header); + if (fsize > fw->size) + goto error_truncated; + /* Extract CSS Header information*/ css_header = (struct intel_css_header *)fw->data; if (sizeof(struct intel_css_header) != @@ -366,6 +373,9 @@ static u32 *parse_csr_fw(struct drm_i915_private *dev_priv, /* Convert dmc_offset into number of bytes. By default it is in dwords*/ dmc_offset *= 4; readcount += dmc_offset; + fsize += dmc_offset; + if (fsize > fw->size) + goto error_truncated; /* Extract dmc_header information. */ dmc_header = (struct intel_dmc_header *)&fw->data[readcount]; @@ -397,6 +407,10 @@ static u32 *parse_csr_fw(struct drm_i915_private *dev_priv, /* fw_size is in dwords, so multiplied by 4 to convert into bytes. */ nbytes = dmc_header->fw_size * 4; + fsize += nbytes; + if (fsize > fw->size) + goto error_truncated; + if (nbytes > csr->max_fw_size) { DRM_ERROR("DMC FW too big (%u bytes)\n", nbytes); return NULL; @@ -410,6 +424,10 @@ static u32 *parse_csr_fw(struct drm_i915_private *dev_priv, } return memcpy(dmc_payload, &fw->data[readcount], nbytes); + +error_truncated: + DRM_ERROR("Truncated DMC firmware, rejecting.\n"); + return NULL; } static void intel_csr_runtime_pm_get(struct drm_i915_private *dev_priv)