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,URIBL_BLOCKED,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 C631BC433E0 for ; Thu, 18 Jun 2020 02:08:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A77AC2088E for ; Thu, 18 Jun 2020 02:08:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592446088; bh=peDTYNHEUfnCxbVfnWAt6h2520DHO5lsM1u8rApleLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1/V0S8nbCNq/pXqx7SmtE2LIWxLzOoP51iLw5bJbXCP7kGiNGMrjLq99EeNmmQF4W SCB/NJ5phED7IaD0m04tbGancQn3JNQq5vW5SeSL7WTbLLC2FgmticR0ggeziSgiaA oX0a4WZD2lEnM8iQeIAMpu1YVnB+Scg7UID9JX0g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730670AbgFRBWK (ORCPT ); Wed, 17 Jun 2020 21:22:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:55022 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730659AbgFRBWJ (ORCPT ); Wed, 17 Jun 2020 21:22:09 -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 D45C920CC7; Thu, 18 Jun 2020 01:22:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443328; bh=peDTYNHEUfnCxbVfnWAt6h2520DHO5lsM1u8rApleLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0thg7zgOyui1J80AsUEj5ocV8iU5Fu10sa1i2RevOY27/8mQZzgX0Tu1fVptKUWvv TQojQJaW/ywL4j+L1z5et9yrZ51PwtCsEq+tkyAYRaPSCIbzCQmyO6HxhG2Z6J6MMf 5xt88RaS+1YOGWqepUSScvZt7SGiXRwNejEEcbKM= 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 5.4 261/266] net/filter: Permit reading NET in load_bytes_relative when MAC not set Date: Wed, 17 Jun 2020 21:16:26 -0400 Message-Id: <20200618011631.604574-261-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618011631.604574-1-sashal@kernel.org> References: <20200618011631.604574-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 f1f2304822e3..a0a492f7cf9c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1766,25 +1766,27 @@ 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