From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 E83FB100AD for ; Wed, 2 Aug 2023 21:15:22 +0000 (UTC) Received: from smtp-fw-6002.amazon.com (smtp-fw-6002.amazon.com [52.95.49.90]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94C612708; Wed, 2 Aug 2023 14:15:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1691010922; x=1722546922; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=UGL2vJ6MLNe12v+8D3skuK9/dM3RwPLrOS4RD+wo23g=; b=hmZCZGQEs8ejNPDN4BHJ31HO/3P2bsaI1lk+Yp4u9PgJMiqUtL3LXpUr 74mNoNdPNKfp0s4Ia58dKLvWxTcix/lcpKLkAvFEdG9pgpxUrUGfbFQpk Oi648UdH8O6pzl06wI4KzaYIAagAS29lz84idQNUrdb5uCycw/WQ0OVbu c=; X-IronPort-AV: E=Sophos;i="6.01,250,1684800000"; d="scan'208";a="348263066" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-pdx-2a-m6i4x-1197e3af.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-6002.iad6.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Aug 2023 21:15:20 +0000 Received: from EX19MTAUWB002.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2a-m6i4x-1197e3af.us-west-2.amazon.com (Postfix) with ESMTPS id 8799310B9AD; Wed, 2 Aug 2023 21:15:18 +0000 (UTC) Received: from EX19D002UWC004.ant.amazon.com (10.13.138.186) by EX19MTAUWB002.ant.amazon.com (10.250.64.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Wed, 2 Aug 2023 21:15:18 +0000 Received: from EX19MTAUWA001.ant.amazon.com (10.250.64.204) by EX19D002UWC004.ant.amazon.com (10.13.138.186) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Wed, 2 Aug 2023 21:15:17 +0000 Received: from dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (10.189.73.169) by mail-relay.amazon.com (10.250.64.204) with Microsoft SMTP Server id 15.2.1118.30 via Frontend Transport; Wed, 2 Aug 2023 21:15:17 +0000 Received: by dev-dsk-risbhat-2b-8bdc64cd.us-west-2.amazon.com (Postfix, from userid 22673075) id AE701E4C; Wed, 2 Aug 2023 21:15:17 +0000 (UTC) From: Rishabh Bhatnagar To: , CC: , , , <"stable@vger.kernel.orgstable"@vger.kernel.org>, Eric Dumazet , Jamal Hadi Salim , Rishabh Bhatnagar Subject: [PATCH 4.19] net/sched: cls_u32: Fix reference counter leak leading to overflow Date: Wed, 2 Aug 2023 21:15:15 +0000 Message-ID: <20230802211515.23078-1-risbhat@amazon.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: Bulk X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Lee Jones Upstream commit 04c55383fa5689357bcdd2c8036725a55ed632bc. In the event of a failure in tcf_change_indev(), u32_set_parms() will immediately return without decrementing the recently incremented reference counter. If this happens enough times, the counter will rollover and the reference freed, leading to a double free which can be used to do 'bad things'. In order to prevent this, move the point of possible failure above the point where the reference counter is incremented. Also save any meaningful return values to be applied to the return data at the appropriate point in time. This issue was caught with KASAN. Fixes: 705c7091262d ("net: sched: cls_u32: no need to call tcf_exts_change for newly allocated struct") Suggested-by: Eric Dumazet Signed-off-by: Lee Jones Reviewed-by: Eric Dumazet Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller Signed-off-by: Rishabh Bhatnagar --- net/sched/cls_u32.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index d30256ac3537..ee8ef606a8e9 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -778,11 +778,22 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp, struct netlink_ext_ack *extack) { int err; +#ifdef CONFIG_NET_CLS_IND + int ifindex = -1; +#endif err = tcf_exts_validate(net, tp, tb, est, &n->exts, ovr, extack); if (err < 0) return err; +#ifdef CONFIG_NET_CLS_IND + if (tb[TCA_U32_INDEV]) { + ifindex = tcf_change_indev(net, tb[TCA_U32_INDEV], extack); + if (ifindex < 0) + return -EINVAL; + } +#endif + if (tb[TCA_U32_LINK]) { u32 handle = nla_get_u32(tb[TCA_U32_LINK]); struct tc_u_hnode *ht_down = NULL, *ht_old; @@ -814,13 +825,8 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp, } #ifdef CONFIG_NET_CLS_IND - if (tb[TCA_U32_INDEV]) { - int ret; - ret = tcf_change_indev(net, tb[TCA_U32_INDEV], extack); - if (ret < 0) - return -EINVAL; - n->ifindex = ret; - } + if (ifindex >= 0) + n->ifindex = ifindex; #endif return 0; } -- 2.40.1