From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50C601F37C3 for ; Tue, 4 Mar 2025 20:05:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741118736; cv=none; b=mb23yLk33d65erSnP3UTQDBXsPBdnYOHpenAZiO6cqy+of4RGu9K2rpY3AhXnaOHmiN7jEbFS3ngw1CZ/3mkll+tmkY8SHism/ibUPkumfGRJhnTbk6Bc+ffDsAdpqb/FL8hFkoZmhLh2L7ydiEuOWjHGy5Pq6jsJ+kwRA8Wo90= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741118736; c=relaxed/simple; bh=Yc5o8AAM03gqcwMaZIMFUJWm5niH57hleRgR8LPA2IQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eNoHsUsWFXNGpxBFBBf2wYo0j4guIgBC5FGd1edLvXNohVPRviLLChXrGMK/sAO9I563px+yG0AvPRhMvD3iELcgLrD+XlvctoevYgk1ZuEHbz5goL2/AZ9S5rlQF5Y1QF0ipbrTrr6I6zZiwdOgWXbGasat6GFd0BKZl4vFkiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=TmqCb+uX; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TmqCb+uX" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-223378e2b0dso88852205ad.0 for ; Tue, 04 Mar 2025 12:05:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741118734; x=1741723534; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Wa+0jqJt7RxZyWEnNlIeijPawv98xKd/6at7dqq5OEU=; b=TmqCb+uX7sWaiS4XmfBV1DOv36dOg6W3108o/g9t201VQX++Iw98DUp2iNze2yzfHo k4f0Vic8Af0xknyoyzFtyL57C8cnlqIn1l7oKEE7oRxGFmx89nGPI+tE/Jgsgy2zuubV 3kQ0C+82/TVfEa53k6L4j2IZBHLlTs5cHtGx8cmY1UBwar21CP/banQ+sZfPrG7fCEhN Aeh8bnc3kBuvcMHSlObPElhNHpBrQFdpugzKqHhSECR9NXTLBlxOUYQLtNrTSAbyo3gk DEHvqxVKEsrnpakvH+NqXhIojQFwN/KucoDUerY1ja2HEknVgEPB/3/akvXmUsDuK3T3 mYGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741118734; x=1741723534; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Wa+0jqJt7RxZyWEnNlIeijPawv98xKd/6at7dqq5OEU=; b=MqSnVBampw9CUfkM1iJ0HUnpENEAJSDp+2SumYZ/lhsyNi/Al9E5Q+JGaH/KAepG0V Lr7mqONu7Z/VycpjR1hHmc+6K5+0CwUZV2jH6ow+USSzHiw3VyQK0yuwO/72bygA3mM9 Z/3H8BMD1SXz9vEaHAz+3It7zG6mlY2KamXY/pmfxrvHG7CIJde5D1yUT4IwYfVB4f+R B0Ay+7YTZYknMQON/OsVhlCrv2j7a5EAb4mwVJMU1eZjQKpEPzQ6MJly6r86Nnil1+AM n828rhSrYZz9jXG21mLG0PiYEmUV63avyl/mCLv7EsmfVBgLpVxChjgEGe6HuUbCLwF1 7D+A== X-Gm-Message-State: AOJu0Yx/iSR2XgfeG0UirJnAq7AXvfj8fOPpLgh9cHiJnzXAUQVKSX5R 5Kk2wYAzxg5OeFdFBE78OjAeqQOuiltZ+iyC6ToOhSh+NSXFgjq3 X-Gm-Gg: ASbGncuCKsWvlxVXyN0r6zML1dj9KF7rsk4osm5zyV+S4XvX75RptBgtkwucZPUpvYF J129v4h7++8X3vyM2dmvP1Tl0MGdAreED1nehRqi+Jrs4GAlI+FdAGXclpvPohzV/LW6eU+L4Dn v/ZXPip0Z4XtFWkt7uRre18E7N9z2K0fIuaUzIhl4MvpfsupSOAKJoiL2x+Ck6JGBMupJVtEoCC SpWnV4zrTRu69QoIn4Bdwa5X/8Ws2Bw4IaPVXdcLmvY6t33EX4xvpT1UGMzXeukUVpc9XCrN1N7 tChxnJ3B1NDPEsp806XKgoGpqHdvt5c2erthVgk0Tr03IcTy X-Google-Smtp-Source: AGHT+IHVOmK8ob84EWFaaF/1pTIbrCtNQCsuHHy++ID7CmBElKeFrrUUESoyh8WvTi7IM2ufOAU6Fg== X-Received: by 2002:a05:6a00:10c8:b0:736:57cb:f2b6 with SMTP id d2e1a72fcca58-73682be66fbmr325371b3a.12.1741118734422; Tue, 04 Mar 2025 12:05:34 -0800 (PST) Received: from localhost ([129.210.115.104]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-735e66ef952sm9029325b3a.98.2025.03.04.12.05.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 12:05:33 -0800 (PST) Date: Tue, 4 Mar 2025 12:05:33 -0800 From: Cong Wang To: kwqcheii Cc: netdev@vger.kernel.org Subject: Re: [PATCH] sched: address a potential NULL pointer dereference in the GRED scheduler. Message-ID: References: <20250227160419.3065643-1-juny24602@gmail.com> <20250304141858.3392957-2-juny24602@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250304141858.3392957-2-juny24602@gmail.com> On Tue, Mar 04, 2025 at 10:18:59PM +0800, kwqcheii wrote: > If kzalloc in gred_init returns a NULL pointer, the code follows the error handling path, > invoking gred_destroy. This, in turn, calls gred_offload, where memset could receive > a NULL pointer as input, potentially leading to a kernel crash. > > Signed-off-by: kwqcheii Please use your real name for Signed-off-by. > --- > net/sched/sch_gred.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c > index ab6234b4fcd5..fa643e5709bd 100644 > --- a/net/sched/sch_gred.c > +++ b/net/sched/sch_gred.c > @@ -317,10 +317,12 @@ static void gred_offload(struct Qdisc *sch, enum tc_gred_command command) > if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) > return; > > - memset(opt, 0, sizeof(*opt)); > - opt->command = command; > - opt->handle = sch->handle; > - opt->parent = sch->parent; > + if (opt) { > + memset(opt, 0, sizeof(*opt)); > + opt->command = command; > + opt->handle = sch->handle; > + opt->parent = sch->parent; > + } I think the whole gred_offload() should be skipped when table->opt == NULL, espeically the last call of ->ndo_setup_tc(). Something like: diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c index ab6234b4fcd5..532fde548b88 100644 --- a/net/sched/sch_gred.c +++ b/net/sched/sch_gred.c @@ -913,7 +913,8 @@ static void gred_destroy(struct Qdisc *sch) for (i = 0; i < table->DPs; i++) gred_destroy_vq(table->tab[i]); - gred_offload(sch, TC_GRED_DESTROY); + if (table->opt) + gred_offload(sch, TC_GRED_DESTROY); kfree(table->opt); } What do you think? Thanks.