From mboxrd@z Thu Jan 1 00:00:00 1970 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 979BAECD983 for ; Thu, 5 Feb 2026 16:15:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 54D8010E913; Thu, 5 Feb 2026 16:15:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Dp2KoBoB"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id 41CE410E913 for ; Thu, 5 Feb 2026 16:15:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1770308132; x=1801844132; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jSTGMS76wzaOXx16IoRmWUKxzuVmR27lmFqETn3KgOM=; b=Dp2KoBoBSzl+i9y6O6YJzB2VTmkBtXL4RSjp5o6NzmG2oUPkPWmitygI BH9b91yK7AHcmENI8wZbOylN0GAtvjT5fSllMJ1OzAOpUgllRw6op5ZW7 yUtPC3/9JpI3IOuWJkSVtmgWpXU+AmfP1dE5iGVjR4J64+ZxFkRoKw1L0 rJV2jHyEVtWX9uTlYVOpaShszxDgIFn5jNzHkm2f5IdceTwE2qhgr0dc4 jXeZ+DvTctGl71DBk0X7uryvw4IMMIePbPktId52wlRSNzl1FkoNQNah7 KRKpi3mGMIWOKc6YzDo4NbY5Nnj06OU6AbsTpglGPrZ5L8JFalQYFMUOt w==; X-CSE-ConnectionGUID: F8pRZ+JHQCWJVgmhToNsnQ== X-CSE-MsgGUID: 3MRAWYVIRVylnQQc138diQ== X-IronPort-AV: E=McAfee;i="6800,10657,11692"; a="82142976" X-IronPort-AV: E=Sophos;i="6.21,274,1763452800"; d="scan'208";a="82142976" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2026 08:15:32 -0800 X-CSE-ConnectionGUID: fx2G/4XkS1GuMC2Xq9k9zg== X-CSE-MsgGUID: 0fgGELw1QF6L/H6IXH+iSQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,274,1763452800"; d="scan'208";a="210379389" Received: from dut6094bmgfrd.fm.intel.com ([10.80.55.45]) by orviesa009.jf.intel.com with ESMTP; 05 Feb 2026 08:15:32 -0800 From: Jia Yao To: intel-xe@lists.freedesktop.org Cc: Jia Yao , Matthew Auld , stable@vger.kernel.org, Matthew Brost , Shuicheng Lin , Himal Prasad Ghimiray , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Rodrigo Vivi Subject: [PATCH v3] drm/xe: Add bounds check on pat_index to prevent OOB kernel read in madvise Date: Thu, 5 Feb 2026 16:15:29 +0000 Message-ID: <20260205161529.1819276-1-jia.yao@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260203172045.1154546-1-jia.yao@intel.com> References: <20260203172045.1154546-1-jia.yao@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" When user provides a bogus pat_index value through the madvise IOCTL, the xe_pat_index_get_coh_mode() function performs an array access without validating bounds. This allows a malicious user to trigger an out-of-bounds kernel read from the xe->pat.table array. The vulnerability exists because the validation in madvise_args_are_sane() directly calls xe_pat_index_get_coh_mode(xe, args->pat_index.val) without first checking if pat_index is within [0, xe->pat.n_entries). Although xe_pat_index_get_coh_mode() has a WARN_ON to catch this in debug builds, it still performs the unsafe array access in production kernels. v2(Matthew Auld) - Using array_index_nospec() to mitigate spectre attacks when the value is used v3(Matthew Auld) - Put the declarations at the start of the block Fixes: ada7486c5668 ("drm/xe: Implement madvise ioctl for xe") Reviewed-by: Matthew Auld Cc: # v6.18+ Cc: Matthew Brost Cc: Shuicheng Lin Cc: Himal Prasad Ghimiray Cc: "Thomas Hellström" Cc: Rodrigo Vivi Cc: Matthew Auld Signed-off-by: Jia Yao --- drivers/gpu/drm/xe/xe_vm_madvise.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c index add9a6ca2390..091e450b781c 100644 --- a/drivers/gpu/drm/xe/xe_vm_madvise.c +++ b/drivers/gpu/drm/xe/xe_vm_madvise.c @@ -246,6 +246,10 @@ static int xe_vm_invalidate_madvise_range(struct xe_vm *vm, u64 start, u64 end) static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madvise *args) { + s32 fd; + u16 pat_index; + u16 coh_mode; + if (XE_IOCTL_DBG(xe, !args)) return false; @@ -261,7 +265,7 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv switch (args->type) { case DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC: { - s32 fd = (s32)args->preferred_mem_loc.devmem_fd; + fd = (s32)args->preferred_mem_loc.devmem_fd; if (XE_IOCTL_DBG(xe, fd < DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM)) return false; @@ -291,8 +295,11 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv break; case DRM_XE_MEM_RANGE_ATTR_PAT: { - u16 coh_mode = xe_pat_index_get_coh_mode(xe, args->pat_index.val); + if (XE_IOCTL_DBG(xe, args->pat_index.val >= xe->pat.n_entries)) + return false; + pat_index = array_index_nospec(args->pat_index.val, xe->pat.n_entries); + coh_mode = xe_pat_index_get_coh_mode(xe, pat_index); if (XE_IOCTL_DBG(xe, !coh_mode)) return false; -- 2.43.0