From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 5831F3F1AAB; Wed, 20 May 2026 14:59:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779289167; cv=none; b=HJ2OQm4rTAHqCGXyNEG/h/IYp6oKys0jAdFRwmstpdSru+O9mWWD6FxivwGOayVaMGYqWCbWFHElYQZAcPx3Ywitlu8/JYOD7iKuSSVGyqebginGVitcoh4Q9g9/RqZUYHzbpjOhbFLEhfPQOdLFv3Vn7EeVX0eqh9vpM4tGwiI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779289167; c=relaxed/simple; bh=HPQnB/wg9UwBu5AE8gehW6Kw6CCIDFaJ/8UovYpXoVE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TBDdA1U/dyYX6VdGtcKju+hTPpnvDVd8PPNDLlidJjoduAqnfyBNtlleAUnVRHjTMchAaMsiSID7B/mxhUs8gXKitRzY8AJtsJ/TrFgHCMBVbm24t9kcuyYysXckVBkuBcoua1SBQ1533c84ONN8u3gWki8iAjtNPyJaEsXwVjs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=QsXv1lwU; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QsXv1lwU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1779289164; x=1810825164; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=HPQnB/wg9UwBu5AE8gehW6Kw6CCIDFaJ/8UovYpXoVE=; b=QsXv1lwUcCvQCdtbn/e+czdH5CvxQqaS+PzToXeuAewjjW0az58EUOlk /8HmNtaKvUU9BVbaqsUUqJ6fCltf83tLep+HYWdt7GHxtGBLHyBMTijAo LIEinyhO+2c/GIkuwpbHJ0MnnNVL8X/iOKpF+hwslsC+YYC2otBoMning uJcmDORe9lJF6rYfxuPWR7EzeL8C755OJbzjVdjGM0fQzG+tSahRKbtvv +hpfNJ0sm5Ul5Fe2+xdoGFoi2/CkfG2c2LaD+mvk8ugivwBUzp0ey10qe Cju1RqiAaBwgglKb5+54nncvtOXGIFZM5KyvldpQKp+UPQFMPQ4roTdX8 A==; X-CSE-ConnectionGUID: PszC9QG9QXCSqFNyTfLDPQ== X-CSE-MsgGUID: FDjIaxhLR9ayTU7YaFb/+Q== X-IronPort-AV: E=McAfee;i="6800,10657,11792"; a="102868226" X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="102868226" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 07:59:23 -0700 X-CSE-ConnectionGUID: GKLVY0yCRjWwvK2YO05caA== X-CSE-MsgGUID: gcDnVwl9T4yhMmN8vsM+mQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="240072001" Received: from bradocaj-mobl.ger.corp.intel.com (HELO [10.125.109.205]) ([10.125.109.205]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 07:59:22 -0700 Message-ID: <8a835dea-956f-4eab-931c-e1a54e14331d@intel.com> Date: Wed, 20 May 2026 07:59:21 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] cxl/region: Fix out of bounds access in cxl_cancel_auto_attach() To: Li Ming Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, Davidlohr Bueso , Jonathan Cameron , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams References: <20260519-fix_out_of_bounds_access-v1-1-55fc60d83388@zohomail.com> <25b0125a-b0fb-4401-8596-3252d2f8cbd6@intel.com> Content-Language: en-US From: Dave Jiang In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/20/26 5:30 AM, Li Ming wrote: > > 在 2026/5/20 01:18, Dave Jiang 写道: >> >> On 5/19/26 6:23 AM, Li Ming wrote: >>> In cxl_cancel_auto_attach(), it assumes cxled->pos is a valid index for >>> accessing p->targets[]. However, cxled->pos can be set to -ENXIO in >> It can be set to other error codes I think? I would just s/-ENXIO/negative errno/ > Sure, Will do that. >> >>> 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. >> Does the comment in cxl_region_sort_targets() need to be updated with the new changes? > > I'm not sure how to update the comment in cxl_region_sort_targets(). Any suggestion? idk if we should just drop it entirely since the comment is no longer true. At least that second part. Alison? > > > Ming > >> >>> Fixes: 87805c32e6ad ("cxl/region: Fix use-after-free from auto assembly failure") >>> Signed-off-by: Li Ming >> The rest LGTM >> >> DJ >> >>> --- >>>   drivers/cxl/core/region.c | 35 ++++++++++++++++------------------- >>>   1 file changed, 16 insertions(+), 19 deletions(-) >>> >>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c >>> index e50dc716d4e8..551228bc91f5 100644 >>> --- a/drivers/cxl/core/region.c >>> +++ b/drivers/cxl/core/region.c >>> @@ -2202,18 +2202,30 @@ 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->nr_targets; 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 +2234,10 @@ 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 * >>> >>> --- >>> base-commit: 5200f5f493f79f14bbdc349e402a40dfb32f23c8 >>> change-id: 20260519-fix_out_of_bounds_access-8838759ee5a6 >>> >>> Best regards,