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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2066C433DF for ; Thu, 18 Jun 2020 01:54:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F07622247 for ; Thu, 18 Jun 2020 01:54:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592445273; bh=kdeBSY1UQnQcLc3FNUD5cVVOyGyzCfr9P780dxsXKuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=o3Pii9hADucNFiydgGn8m2ioviMd13MA4juqDmhovzneBQYMvg1LB+9xN/kUhSVJ1 76bCMlmC4+xXKIqYYH1uQqqAPN/ijynXoPgXJzyRDQ3K/2TNuMjZ7G55ZB1/1g2AFv cmflo1cCeeulwP/+rNrqM+oq9bWpzJ2WneCxVSD8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731558AbgFRB0A (ORCPT ); Wed, 17 Jun 2020 21:26:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:33184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729472AbgFRBZ6 (ORCPT ); Wed, 17 Jun 2020 21:25:58 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7A69B20897; Thu, 18 Jun 2020 01:25:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443557; bh=kdeBSY1UQnQcLc3FNUD5cVVOyGyzCfr9P780dxsXKuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PHFF1SfDSY1OlCZ0ZjgLf69QQcnPzZdHNGAeJvGwsYKwXU8YhLIMl3r7ZmmOCVfPj 1W55eOSz8ZSAlnNQQyQbjlk+9TZoyqNmtjvIqisEyezjQsdymZUwekPRKJHm10iiLj 2vZJCIkY8Z3eOQRGWsyIV5V5Xxo13y7Em5ok0JfI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: YiFei Zhu , YiFei Zhu , Daniel Borkmann , Stanislav Fomichev , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 171/172] net/filter: Permit reading NET in load_bytes_relative when MAC not set Date: Wed, 17 Jun 2020 21:22:17 -0400 Message-Id: <20200618012218.607130-171-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012218.607130-1-sashal@kernel.org> References: <20200618012218.607130-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: YiFei Zhu [ Upstream commit 0f5d82f187e1beda3fe7295dfc500af266a5bd80 ] Added a check in the switch case on start_header that checks for the existence of the header, and in the case that MAC is not set and the caller requests for MAC, -EFAULT. If the caller requests for NET then MAC's existence is completely ignored. There is no function to check NET header's existence and as far as cgroup_skb/egress is concerned it should always be set. Removed for ptr >= the start of header, considering offset is bounded unsigned and should always be true. len <= end - mac is redundant to ptr + len <= end. Fixes: 3eee1f75f2b9 ("bpf: fix bpf_skb_load_bytes_relative pkt length check") Signed-off-by: YiFei Zhu Signed-off-by: Daniel Borkmann Reviewed-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/76bb820ddb6a95f59a772ecbd8c8a336f646b362.1591812755.git.zhuyifei@google.com Signed-off-by: Sasha Levin --- net/core/filter.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 40b3af05c883..b5521b60a2d4 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1730,25 +1730,27 @@ BPF_CALL_5(bpf_skb_load_bytes_relative, const struct sk_buff *, skb, u32, offset, void *, to, u32, len, u32, start_header) { u8 *end = skb_tail_pointer(skb); - u8 *net = skb_network_header(skb); - u8 *mac = skb_mac_header(skb); - u8 *ptr; + u8 *start, *ptr; - if (unlikely(offset > 0xffff || len > (end - mac))) + if (unlikely(offset > 0xffff)) goto err_clear; switch (start_header) { case BPF_HDR_START_MAC: - ptr = mac + offset; + if (unlikely(!skb_mac_header_was_set(skb))) + goto err_clear; + start = skb_mac_header(skb); break; case BPF_HDR_START_NET: - ptr = net + offset; + start = skb_network_header(skb); break; default: goto err_clear; } - if (likely(ptr >= mac && ptr + len <= end)) { + ptr = start + offset; + + if (likely(ptr + len <= end)) { memcpy(to, ptr, len); return 0; } -- 2.25.1