From nobody Sun Feb 8 12:42:53 2026 Received: from smtp-relay-internal-1.canonical.com (smtp-relay-internal-1.canonical.com [185.125.188.123]) (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 30DF6748F for ; Thu, 4 Jul 2024 09:35:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.125.188.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720085752; cv=none; b=Rpbo7nx5pvswgk5/BQ2VxzaNPXJ2PwGsaXn0EJHHjGGhH4tlw+ZwAfKi1tsuU90I39+xSCmlLd2FK50WKZsFWZtqnKkqYs7xfLNfGo2REVQSTrmCMRwlKuOvJiWoW9gXKrOH6ormm20naop3rmEtmbrYuD/4sp/3nLKRS/o8JpY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720085752; c=relaxed/simple; bh=Oy7dKvHiGFYXx+I7lg+7RcbtYemeYKr5TDO40BXEiQU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=iUa4i5PVXxFMvFul8xVPsyTfEzc8iQdLt3F85X1JzjZ4UwDsictgLKfr2GBj7Z+HLH5+92xafvPNk4tPa+een1aESfa/cTHWlp1OdTWd9r3rZZBuYOSxtMkWWAWXaccv0iKna5Ps7mJHNxYG6nu3th2jrOAiabNfzpiUZe/3mLw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canonical.com; spf=pass smtp.mailfrom=canonical.com; dkim=pass (2048-bit key) header.d=canonical.com header.i=@canonical.com header.b=BqeXAgxq; arc=none smtp.client-ip=185.125.188.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canonical.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=canonical.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=canonical.com header.i=@canonical.com header.b="BqeXAgxq" Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-1.canonical.com (Postfix) with ESMTPS id 0BB6041339 for ; Thu, 4 Jul 2024 09:35:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1720085743; bh=wiJxNUkYycJsSDpu62b6poSEZxZfrfFCF631xd6P5LQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BqeXAgxqcrdV45sk9xOM7lRosB1soHhpNIWWVM7GBGLNspO6K8ZhDvhcv7ytlM62Y BikOrPveuJh9DIt2PRcvrwNIefEyRdb/4iwCMaQGTWL8bWeF2aXMXd+AMBHzUb/7Df 5RRrqmAf0/sEBkj8g2+ctslk9UsLOoYwC26Roq9Oz1WJE4CzHBB7XeEvmHFE1qUhTU gVu7TIHe1pfKm2UNsMoP2hiW3vNV0s3eMnbXuTT7dNMVbm83sS956Z2aCKvn/TAMIk nkQTCCj+aHA3sM4/cS5fiQrJAEfn0b5gSXwcnenaRagwdOgeV9syLV4ccfWhjIu05w oqf5P/GsYRt8g== Received: by mail-pl1-f199.google.com with SMTP id d9443c01a7336-1faad2eb0a3so12530345ad.0 for ; Thu, 04 Jul 2024 02:35:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720085733; x=1720690533; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=wiJxNUkYycJsSDpu62b6poSEZxZfrfFCF631xd6P5LQ=; b=FUtJPEJ+TceGJIaiNeffb4yOG8W1gTCc0GGl/hewqKogYkt6Qs8F+DpeyGz2hrxIPL /wXgoLndfC0gjjpzlTOuRs+nik8D/gvHvV8oo2kcFqOW4rx+I0IAhtz2YKzd3N0UWy5v Xn+6NxYj7cT4lFEy0oMashAXBZ6VQ1+R7D++qXWm8nE/MTfHnb5vnnUqfwQflJtbuH6j FVk3J5zvFX1ix1Rtcc+DhzdSnCx/cNY/vbo1ng4YwtvJktiCA7n5c89OHNm+fTyhhIjF yyVhKohuCrnk4YiedLOUG9RPYqe9ZihdX/WGP8dyYZVBBXx/gXduV0ws6id/1FonQwPM EvQQ== X-Forwarded-Encrypted: i=1; AJvYcCUWHlByzIDQkWyAsQnFAiLbqA2lCxbw4dSrE+Zz+yuhAtx2BZlEt49DPCraAj3dVfeVyLKpfipu5xPG4inl1+V6/XDRDdqdYHvU7ICZ X-Gm-Message-State: AOJu0YyNcMhYymwm5JionRkz8aRnrZ4u2k7XxiXpylzTNn7LvQLW37/p KuQtdUpQ1Za2RTaQIsPK/SWdC5bNa0scPONRb3KlKl3UbmbzrftdO6WHZOGzS7o1A2dSDMqdFUB E1Q5VE9ZY61oe1O9tcuh+nYTyfTNa8+uD2Yb4ljgyJEq/tnSH6KlnuWvaLztvQMzViDFl2jEmC5 3lVQ== X-Received: by 2002:a17:902:cecb:b0:1fb:2e1d:acdb with SMTP id d9443c01a7336-1fb37047770mr13990575ad.12.1720085733622; Thu, 04 Jul 2024 02:35:33 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEOXt2HSyqcWAnEGOSShpHjEDdGJVAIPy5yyNQs45QakgMU34R+QMFUZG8sl5Weo2rhUKkcsg== X-Received: by 2002:a17:902:cecb:b0:1fb:2e1d:acdb with SMTP id d9443c01a7336-1fb37047770mr13990185ad.12.1720085733186; Thu, 04 Jul 2024 02:35:33 -0700 (PDT) Received: from chengendu.. (2001-b011-381c-3667-42c0-8e79-026a-04b5.dynamic-ip6.hinet.net. [2001:b011:381c:3667:42c0:8e79:26a:4b5]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1fac15992a0sm118498515ad.263.2024.07.04.02.35.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jul 2024 02:35:32 -0700 (PDT) From: Chengen Du To: jhs@mojatatu.com Cc: xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ozsh@nvidia.com, paulb@nvidia.com, marcelo.leitner@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Chengen Du , Gerald Yang Subject: [PATCH] net/sched: Fix UAF when resolving a clash Date: Thu, 4 Jul 2024 17:34:58 +0800 Message-ID: <20240704093458.39198-1-chengen.du@canonical.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: quoted-printable Content-Type: text/plain; charset="utf-8" KASAN reports the following UAF: BUG: KASAN: slab-use-after-free in tcf_ct_flow_table_process_conn+0x12b/0x= 380 [act_ct] Read of size 1 at addr ffff888c07603600 by task handler130/6469 Call Trace: dump_stack_lvl+0x48/0x70 print_address_description.constprop.0+0x33/0x3d0 print_report+0xc0/0x2b0 kasan_report+0xd0/0x120 __asan_load1+0x6c/0x80 tcf_ct_flow_table_process_conn+0x12b/0x380 [act_ct] tcf_ct_act+0x886/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 __irq_exit_rcu+0x82/0xc0 irq_exit_rcu+0xe/0x20 common_interrupt+0xa1/0xb0 asm_common_interrupt+0x27/0x40 Allocated by task 6469: kasan_save_stack+0x38/0x70 kasan_set_track+0x25/0x40 kasan_save_alloc_info+0x1e/0x40 __kasan_krealloc+0x133/0x190 krealloc+0xaa/0x130 nf_ct_ext_add+0xed/0x230 [nf_conntrack] tcf_ct_act+0x1095/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 Freed by task 6469: kasan_save_stack+0x38/0x70 kasan_set_track+0x25/0x40 kasan_save_free_info+0x2b/0x60 ____kasan_slab_free+0x180/0x1f0 __kasan_slab_free+0x12/0x30 slab_free_freelist_hook+0xd2/0x1a0 __kmem_cache_free+0x1a2/0x2f0 kfree+0x78/0x120 nf_conntrack_free+0x74/0x130 [nf_conntrack] nf_ct_destroy+0xb2/0x140 [nf_conntrack] __nf_ct_resolve_clash+0x529/0x5d0 [nf_conntrack] nf_ct_resolve_clash+0xf6/0x490 [nf_conntrack] __nf_conntrack_confirm+0x2c6/0x770 [nf_conntrack] tcf_ct_act+0x12ad/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 The ct may be dropped if a clash has been resolved but is still passed to the tcf_ct_flow_table_process_conn function for further usage. This issue can be fixed by retrieving ct from skb again after confirming conntrack. Fixes: 0cc254e5aa37 ("net/sched: act_ct: Offload connections with commit ac= tion") Co-developed-by: Gerald Yang Signed-off-by: Gerald Yang Signed-off-by: Chengen Du --- net/sched/act_ct.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index 2a96d9c1db65..079562f6ca71 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -1077,6 +1077,13 @@ TC_INDIRECT_SCOPE int tcf_ct_act(struct sk_buff *skb= , const struct tc_action *a, */ if (nf_conntrack_confirm(skb) !=3D NF_ACCEPT) goto drop; + /* The ct may be dropped if a clash has been resolved, + * so it's necessary to retrieve it from skb again to + * prevent UAF. + */ + ct =3D nf_ct_get(skb, &ctinfo); + if (!ct) + goto drop; } =20 if (!skip_add) --=20 2.43.0