From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9B4373DD870; Tue, 21 Jul 2026 18:16:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657792; cv=none; b=risZL2dvjNOKUsxX3c4YOG5iFf3TAHG6j7tYBOfEMa52eoL4rbZjQV+CER8NgywEJEmC7jF2XmkvCowsvBElzEwI8JOQDS8nYycos1SYWN0iEKPGyHtYEjRHEWOxzT/ayLCcUGTGd545vzPJvE53eoRd/SMWzeQpfd9zZg+TrIE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657792; c=relaxed/simple; bh=ntVNfD6GSW6wrPKT+Xc9qHLQTKBwlmt/f5rf8PFxd5Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NeoVL0QtEu7tsXOCz45czes9UE1uF/+qgt/zv5fbY0MCE/hnrX7y0Hy4wL3OSeBEKE/U5zMNC5/1VteUhTAN0bHn6saAkB0X2x/XaUUMCgl0wZhnJ0UYfyxdsFWApxhXOOaDL1+S3PjTaIbQQZERauGfPx1wyGwSW7kLgZIBLsU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=omnFMy/b; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="omnFMy/b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CFEE1F00A3F; Tue, 21 Jul 2026 18:16:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657791; bh=gAkXwdeEhW+zobkLI4N40FfkxcqqcOJ1ouqj4/V7QgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=omnFMy/bHsqJtIYeLenPhR7lTzkAnu4WnB4q0ao/ICejEUOYx5VnaRZYrusDNQ6yC k13Ljr5l8tIvd48FQyOrqPcWWSMRnyUx5qotJcO1iQIwdXIpPdJvgar8Wpwy/2q/XO fyBKewedPWcnIhSbdQX+4UsNnP9T7hV++6vDNBkc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Jani Nikula , Sasha Levin Subject: [PATCH 6.18 0882/1611] drm/edid: fix OOB read in drm_parse_tiled_block() Date: Tue, 21 Jul 2026 17:16:38 +0200 Message-ID: <20260721152535.229861953@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit faaa1e1155833e7d4ce7e3cfaf64c0d636b190db ] drm_parse_tiled_block() casts the DisplayID block to a struct displayid_tiled_block and reads the full fixed layout up to tile->topology_id[7] without checking block->num_bytes. The DisplayID iterator only validates the declared payload length, so a crafted EDID can advertise a tiled-display block (tag DATA_BLOCK_TILED_DISPLAY, or DATA_BLOCK_2_TILED_DISPLAY_TOPOLOGY for v2.0) with a small num_bytes at the end of a DisplayID extension. The read then runs past the end of the exact-sized kmemdup()'d EDID allocation, a heap out-of-bounds read. Reject blocks shorter than the spec's 22-byte tiled payload before reading the fixed struct, as drm_parse_vesa_mso_data() already does. BUG: KASAN: slab-out-of-bounds in drm_edid_connector_update Read of size 2 at addr ffff888010077700 by task exploit/147 dump_stack_lvl (lib/dump_stack.c:94 ...) print_report (mm/kasan/report.c:378 ...) kasan_report (mm/kasan/report.c:595) drm_edid_connector_update (drivers/gpu/drm/drm_edid.c:7581) bochs_connector_helper_get_modes (drivers/gpu/drm/tiny/bochs.c:574) drm_helper_probe_single_connector_modes (drivers/gpu/drm/drm_probe_helper.c:426) status_store (drivers/gpu/drm/drm_sysfs.c:219) ... vfs_write (fs/read_write.c:595 fs/read_write.c:688) ksys_write (fs/read_write.c:740) Fixes: 40d9b043a89e ("drm/connector: store tile information from displayid (v3)") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Reviewed-by: Jani Nikula Link: https://patch.msgid.link/20260615184737.899892-1-xmei5@asu.edu Signed-off-by: Jani Nikula Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_edid.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index e2e85345aa9a40..046b5e86a78731 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -7500,6 +7500,14 @@ static void drm_parse_tiled_block(struct drm_connector *connector, u8 num_v_tile, num_h_tile; struct drm_tile_group *tg; + /* tiled block payload per spec: cap 1 + topo 3 + size 4 + bezel 5 + id 9 = 22 */ + if (block->num_bytes < 22) { + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] Unexpected tiled block size %u\n", + connector->base.id, connector->name, block->num_bytes); + return; + } + w = tile->tile_size[0] | tile->tile_size[1] << 8; h = tile->tile_size[2] | tile->tile_size[3] << 8; -- 2.53.0