From patchwork Thu Apr 13 18:06:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sui Jingfeng <15330273260@189.cn> X-Patchwork-Id: 13210496 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 8656FC77B6E for ; Thu, 13 Apr 2023 18:07:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229577AbjDMSHE (ORCPT ); Thu, 13 Apr 2023 14:07:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229498AbjDMSHE (ORCPT ); Thu, 13 Apr 2023 14:07:04 -0400 Received: from 189.cn (ptr.189.cn [183.61.185.104]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 65BD91735; Thu, 13 Apr 2023 11:07:01 -0700 (PDT) HMM_SOURCE_IP: 10.64.8.41:59970.367170433 HMM_ATTACHE_NUM: 0000 HMM_SOURCE_TYPE: SMTP Received: from clientip-114.242.206.180 (unknown [10.64.8.41]) by 189.cn (HERMES) with SMTP id 840D410029F; Fri, 14 Apr 2023 02:06:59 +0800 (CST) Received: from ([114.242.206.180]) by gateway-151646-dep-7b48884fd-bkw2h with ESMTP id 7ce36ef6dddf4c1da3378e2ce90cb046 for mripard@kernel.org; Fri, 14 Apr 2023 02:07:00 CST X-Transaction-ID: 7ce36ef6dddf4c1da3378e2ce90cb046 X-Real-From: 15330273260@189.cn X-Receive-IP: 114.242.206.180 X-MEDUSA-Status: 0 Sender: 15330273260@189.cn From: Sui Jingfeng <15330273260@189.cn> To: Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Sui Jingfeng , Li Yi , Javier Martinez Canillas , Helge Deller , Lucas De Marchi Cc: linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, loongson-kernel@lists.loongnix.cn Subject: [PATCH v2] drm/fbdev-generic: prohibit potential out-of-bounds access Date: Fri, 14 Apr 2023 02:06:22 +0800 Message-Id: <20230413180622.1014016-1-15330273260@189.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Sui Jingfeng The crazy fbdev test of IGT may write after EOF, which lead to out-of-bound access for the drm drivers using fbdev-generic. For example, run fbdev test on a x86-64+ast2400 platform with 1680x1050 resolution will cause the linux kernel hang with following call trace: Oops: 0000 [#1] PREEMPT SMP PTI [IGT] fbdev: starting subtest eof Workqueue: events drm_fb_helper_damage_work [drm_kms_helper] [IGT] fbdev: starting subtest nullptr RIP: 0010:memcpy_erms+0xa/0x20 RSP: 0018:ffffa17d40167d98 EFLAGS: 00010246 RAX: ffffa17d4eb7fa80 RBX: ffffa17d40e0aa80 RCX: 00000000000014c0 RDX: 0000000000001a40 RSI: ffffa17d40e0b000 RDI: ffffa17d4eb80000 RBP: ffffa17d40167e20 R08: 0000000000000000 R09: ffff89522ecff8c0 R10: ffffa17d4e4c5000 R11: 0000000000000000 R12: ffffa17d4eb7fa80 R13: 0000000000001a40 R14: 000000000000041a R15: ffffa17d40167e30 FS: 0000000000000000(0000) GS:ffff895257380000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffa17d40e0b000 CR3: 00000001eaeca006 CR4: 00000000001706e0 Call Trace: ? drm_fbdev_generic_helper_fb_dirty+0x207/0x330 [drm_kms_helper] drm_fb_helper_damage_work+0x8f/0x170 [drm_kms_helper] process_one_work+0x21f/0x430 worker_thread+0x4e/0x3c0 ? __pfx_worker_thread+0x10/0x10 kthread+0xf4/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 CR2: ffffa17d40e0b000 ---[ end trace 0000000000000000 ]--- The indirect reason is drm_fb_helper_memory_range_to_clip() generate damage rectangles which partially or completely go out of the active display area. The second of argument 'off' is passing from the user-space, this will lead to the out-of-bound if it is large than (fb_height + 1) * fb_pitches; while DIV_ROUND_UP() may also controbute to error by 1. This patch will add code to restrict the damage rect computed go beyond of the last line of the framebuffer. Signed-off-by: Sui Jingfeng --- drivers/gpu/drm/drm_fb_helper.c | 16 ++++++++++++---- drivers/gpu/drm/drm_fbdev_generic.c | 2 +- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 64458982be40..6bb1b8b27d7a 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -641,19 +641,27 @@ static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y, static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len, struct drm_rect *clip) { + u32 line_length = info->fix.line_length; + u32 fb_height = info->var.yres; off_t end = off + len; u32 x1 = 0; - u32 y1 = off / info->fix.line_length; + u32 y1 = off / line_length; u32 x2 = info->var.xres; - u32 y2 = DIV_ROUND_UP(end, info->fix.line_length); + u32 y2 = DIV_ROUND_UP(end, line_length); + + /* Don't allow any of them beyond the bottom bound of display area */ + if (y1 > fb_height) + y1 = fb_height; + if (y2 > fb_height) + y2 = fb_height; if ((y2 - y1) == 1) { /* * We've only written to a single scanline. Try to reduce * the number of horizontal pixels that need an update. */ - off_t bit_off = (off % info->fix.line_length) * 8; - off_t bit_end = (end % info->fix.line_length) * 8; + off_t bit_off = (off % line_length) * 8; + off_t bit_end = (end % line_length) * 8; x1 = bit_off / info->var.bits_per_pixel; x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel); diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c index 8e5148bf40bb..b057cfbba938 100644 --- a/drivers/gpu/drm/drm_fbdev_generic.c +++ b/drivers/gpu/drm/drm_fbdev_generic.c @@ -94,7 +94,7 @@ static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper, fb_helper->buffer = buffer; fb_helper->fb = buffer->fb; - screen_size = buffer->gem->size; + screen_size = sizes->surface_height * buffer->fb->pitches[0]; screen_buffer = vzalloc(screen_size); if (!screen_buffer) { ret = -ENOMEM;