From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-o94.zoho.com (sender4-pp-o94.zoho.com [136.143.188.94]) (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 8580332B109; Sun, 24 May 2026 09:56:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.94 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779616598; cv=pass; b=LgxHULoLPOrUBOlRMrHoWKtbS0OEbeDIBNzktTWLz+Jvgw60BMFUeyk3oEMkAT3sN0pP+LzrK3FpvYz8g7C95LgKaMBHvAtqndm6arcMm1SLuXr1OgzVDjzkbvHHrxZuTQGuYl9FuXmsQHrDo7WOhYTuPzvuHBu9sj5CAdCj1no= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779616598; c=relaxed/simple; bh=3evzGI8ydlntYUzNqJn8pFf8/D934Cn6h0RJyPqDnaE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XYQU3oTCZxsOFDKT/NAO/vUOBgbEg1hpiDJ5JyJktCjwy0Y1hiioq7uFzQ9b7Ho6QHj268JfqW1QmtaKFmeuNAtGlIy6Qz/DpCnQiCI0cc/PqUwIAwrlGOF6q52PXW4+jueceuvVTJI+E6Yahc1YO97ZWH4ksepMPu+nzCWvYkM= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com; spf=pass smtp.mailfrom=zohomail.com; dkim=pass (1024-bit key) header.d=zohomail.com header.i=ming.li@zohomail.com header.b=PHSV+xo4; arc=pass smtp.client-ip=136.143.188.94 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zohomail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zohomail.com header.i=ming.li@zohomail.com header.b="PHSV+xo4" ARC-Seal: i=1; a=rsa-sha256; t=1779616589; cv=none; d=zohomail.com; s=zohoarc; b=CYD1K1ptZ2gVQd+XSOz1THLYqiovXr/2vWM9ecDHPYvCXlvwDTgeWYLWjixPaDRKO06eY/dwRTfCOEfaGXNPzSdsFyaObo2zXa/9S0SL3PHhG7lI8TnCBhW2jS6B2d2hxXBVN3WI7X//TqWBVVVU0OKSUWVckppsi9u/hsHUkHw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779616589; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=LbfxgxO+Vn0lgyF+08e1lUphD91UlmVCase93BEmJec=; b=j33J5QCI4NdYzONCycdapUeA+dNsAgEGkkqaPuvVtWIBdzIAYMWsLQO6OB8PcdU8bWMlSbnm9+q/FPkr93IHEH9jjkz/IIPFBN/ypp8PedGFHKLmcTt/fvQqhPzoM2QQ2WkTTsqelEpyUQuOAU4eo/T341GVTfQQ7wokAkDTNCA= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=zohomail.com; spf=pass smtp.mailfrom=ming.li@zohomail.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779616589; s=zm2022; d=zohomail.com; i=ming.li@zohomail.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:MIME-Version:Content-Transfer-Encoding:Feedback-ID:Message-Id:Reply-To; bh=LbfxgxO+Vn0lgyF+08e1lUphD91UlmVCase93BEmJec=; b=PHSV+xo4qvmJLnMEVbcGZhnrlJUwGHsZzPH55eBmeWe3Ep8Ehlzpjn3Ns2zM3Rz5 iTNyjeIF7KlUyHbbrt+2m0GOMYh3TJAitxXzHZ3ob3z7qVvYfvouKmFFEpakRQ4lhfg 1KAayE3UT8iBWcSjAlAuahk0aEWI9PHk6CbjzJZo= Received: by mx.zohomail.com with SMTPS id 1779616586755771.2567109612221; Sun, 24 May 2026 02:56:26 -0700 (PDT) From: Li Ming To: dave@stgolabs.net, jic23@kernel.org, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, djbw@kernel.org Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/1] cxl/region: Fix out-of-bounds access in cxl_cancel_auto_attach() Date: Sun, 24 May 2026 17:56:20 +0800 Message-ID: <20260524095620.636535-1-ming.li@zohomail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Feedback-ID: zu080112276625901bc1b5317b5bb2ed210000c8babd66bbe57849d15ea7203a6385b3da6d7e3f6048f4a446:ZohoMail X-Zoho-CM-AccountID: abd763e7b9fa23acf4f42a44f9876d2d993e05abdb9290f9ccb1008c977bf7f0 X-ZohoMailClient: External In cxl_cancel_auto_attach(), it assumes cxled->pos is a valid index for accessing p->targets[]. However, cxled->pos can be set to negative errno in cxl_region_sort_targets() if cxl_calc_interleave_pos() fails. This causes the driver to use a negative index to access p->targets[], resulting in out-of-bounds access. Fix it by walking p->targets[] instead of using cxled->pos directly. Fixes: 87805c32e6ad ("cxl/region: Fix use-after-free from auto assembly failure") Signed-off-by: Li Ming --- Changes from v1: - Update commit log. (Dave) - Update comment in cxl_region_sort_targets(). (Dave) - Fix potential 'hole' issue. (Alison & Sashiko review) --- drivers/cxl/core/region.c | 40 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index e50dc716d4e8..8956b049c462 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2011,8 +2011,9 @@ static int cxl_region_sort_targets(struct cxl_region *cxlr) cxled->pos = cxl_calc_interleave_pos(cxled, &cxlr->hpa_range); /* * Record that sorting failed, but still continue to calc - * cxled->pos so that follow-on code paths can reliably - * do p->targets[cxled->pos] to self-reference their entry. + * cxled->pos so that cxl_calc_interleave_pos() emits its + * dev_dbg() for every member. which is useful for auto + * discovery debug. */ if (cxled->pos < 0) rc = -ENXIO; @@ -2202,18 +2203,30 @@ static int cxl_region_attach(struct cxl_region *cxlr, return 0; } -static int cxl_region_by_target(struct device *dev, const void *data) +static int cxl_region_remove_target(struct device *dev, void *data) { - const struct cxl_endpoint_decoder *cxled = data; + struct cxl_endpoint_decoder *cxled = data; struct cxl_region_params *p; struct cxl_region *cxlr; + int i; if (!is_cxl_region(dev)) return 0; cxlr = to_cxl_region(dev); p = &cxlr->params; - return p->targets[cxled->pos] == cxled; + for (i = 0; i < p->interleave_ways; i++) { + if (p->targets[i] == cxled) { + p->nr_targets--; + cxled->state = CXL_DECODER_STATE_AUTO; + cxled->pos = -1; + p->targets[i] = NULL; + + return 1; + } + } + + return 0; } /* @@ -2222,25 +2235,10 @@ static int cxl_region_by_target(struct device *dev, const void *data) */ static void cxl_cancel_auto_attach(struct cxl_endpoint_decoder *cxled) { - struct cxl_region_params *p; - struct cxl_region *cxlr; - int pos = cxled->pos; - if (cxled->state != CXL_DECODER_STATE_AUTO_STAGED) return; - struct device *dev __free(put_device) = - bus_find_device(&cxl_bus_type, NULL, cxled, cxl_region_by_target); - if (!dev) - return; - - cxlr = to_cxl_region(dev); - p = &cxlr->params; - - p->nr_targets--; - cxled->state = CXL_DECODER_STATE_AUTO; - cxled->pos = -1; - p->targets[pos] = NULL; + bus_for_each_dev(&cxl_bus_type, NULL, cxled, cxl_region_remove_target); } static struct cxl_region * -- 2.43.0