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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C3E5C6FD1C for ; Wed, 22 Mar 2023 03:38:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230039AbjCVDil (ORCPT ); Tue, 21 Mar 2023 23:38:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229672AbjCVDik (ORCPT ); Tue, 21 Mar 2023 23:38:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88A0026580 for ; Tue, 21 Mar 2023 20:38:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 21E9E61F32 for ; Wed, 22 Mar 2023 03:38:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93C11C433D2; Wed, 22 Mar 2023 03:38:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679456318; bh=gLUp0cD/dekHocn9k+RGGh2H9rq74WePOC0Uvf/tGCc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NlaPS58kclFxumjA/N9Cyzjp2djT5rLsKJof7ONGQVwZCUNbMsL1MzEEpRZk0rUat bApPHKCwDfTPfPXCx5CDNH3fuG2tfMRtDXgolElBGfU8hcLj/rI30W0q5poKy0I6jr VPiwGV3WDGJjQ5zOVo7Qpq3b0F0Wl+0aILK32KLickv+v0Hw4ycCTZ6QVqH1yYhWsQ KOtd5hUgM/RqWB8MtAJSYF2dUpmCDiK40mzNTuEl6UJOdDZzQ0ALE0dy1HxuaF3Sn1 fzPhFUcDXbIdcPpeC9IK4KvNue6SF5hrG8+oDkFNcS7VLbUi/3/KDAnUN9NjGUpfUF uRAziuYbSUiRw== Date: Tue, 21 Mar 2023 20:38:36 -0700 From: Jakub Kicinski To: Saeed Mahameed Cc: "David S. Miller" , Paolo Abeni , Eric Dumazet , Saeed Mahameed , netdev@vger.kernel.org, Tariq Toukan , Eli Cohen Subject: Re: [net-next 01/14] lib: cpu_rmap: Avoid use after free on rmap->obj array entries Message-ID: <20230321203836.5ab4951e@kernel.org> In-Reply-To: <20230320175144.153187-2-saeed@kernel.org> References: <20230320175144.153187-1-saeed@kernel.org> <20230320175144.153187-2-saeed@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 20 Mar 2023 10:51:31 -0700 Saeed Mahameed wrote: > From: Eli Cohen > > When calling irq_set_affinity_notifier() with NULL at the notify > argument, it will cause freeing of the glue pointer in the > corresponding array entry but will leave the pointer in the array. A > subsequent call to free_irq_cpu_rmap() will try to free this entry again > leading to possible use after free. > > Fix that by setting NULL to the array entry and checking that we have > non-zero at the array entry when iterating over the array in > free_irq_cpu_rmap(). Commit message needs some work. Are you trying to make double free_irq_cpu_rmap() work fine because of callers? Are there problems with error path of irq_cpu_rmap_add()? I can tell what you're trying to prevent but not why. > Fixes: c39649c331c7 ("lib: cpu_rmap: CPU affinity reverse-mapping") What is this Fixes tag doing in a net-next patch :S If it can be triggered it needs to go to net. > Signed-off-by: Eli Cohen > Signed-off-by: Saeed Mahameed > --- > lib/cpu_rmap.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c > index f08d9c56f712..e77f12bb3c77 100644 > --- a/lib/cpu_rmap.c > +++ b/lib/cpu_rmap.c > @@ -232,7 +232,8 @@ void free_irq_cpu_rmap(struct cpu_rmap *rmap) > > for (index = 0; index < rmap->used; index++) { After looking at this code for 10min - isn't the problem that used is never decremented on the error path? I don't see a way to remove from the map so it can't be sparse. > glue = rmap->obj[index]; > - irq_set_affinity_notifier(glue->notify.irq, NULL); > + if (glue) > + irq_set_affinity_notifier(glue->notify.irq, NULL); > } > > cpu_rmap_put(rmap); > @@ -268,6 +269,7 @@ static void irq_cpu_rmap_release(struct kref *ref) > container_of(ref, struct irq_glue, notify.kref); > > cpu_rmap_put(glue->rmap); > + glue->rmap->obj[glue->index] = NULL; > kfree(glue); > } > > @@ -297,6 +299,7 @@ int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq) > rc = irq_set_affinity_notifier(irq, &glue->notify); > if (rc) { > cpu_rmap_put(glue->rmap); > + rmap->obj[glue->index] = NULL; > kfree(glue); > } > return rc;