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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8460C433EF for ; Mon, 11 Apr 2022 11:30:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344742AbiDKLc5 (ORCPT ); Mon, 11 Apr 2022 07:32:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245270AbiDKLcx (ORCPT ); Mon, 11 Apr 2022 07:32:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7CA33EF3D for ; Mon, 11 Apr 2022 04:30:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 81C8E61584 for ; Mon, 11 Apr 2022 11:30:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 884DBC385A4; Mon, 11 Apr 2022 11:30:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649676637; bh=bkUIk10vrOVoWZmafk837qUFVsGWOoSb6CwajV+KVUY=; h=Subject:To:Cc:From:Date:From; b=yHfJGWeNZPQ1TnYd3/p0yfCaChYoEu+V0C1Pu1E/gI4coq4w6VkcNHbO9s74Fc2/C eN0ayokveueCeJGpHz1ybwl1uZ31MVuAfAg62UQ7ib1dEKG4wVEhoQjzYcaS8+hXOf u0U0Po5jImgdJiIDlbitzHn3qF29UQT+b5f7Q0To= Subject: FAILED: patch "[PATCH] bpf: Treat bpf_sk_lookup remote_port as a 2-byte field" failed to apply to 5.16-stable tree To: jakub@cloudflare.com, ast@kernel.org, kafai@fb.com Cc: From: Date: Mon, 11 Apr 2022 13:30:34 +0200 Message-ID: <1649676634204182@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.16-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 058ec4a7d9cf77238c73ad9f1e1a3ed9a29afcab Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Sat, 19 Mar 2022 19:33:54 +0100 Subject: [PATCH] bpf: Treat bpf_sk_lookup remote_port as a 2-byte field In commit 9a69e2b385f4 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") the remote_port field has been split up and re-declared from u32 to be16. However, the accompanying changes to the context access converter have not been well thought through when it comes big-endian platforms. Today 2-byte wide loads from offsetof(struct bpf_sk_lookup, remote_port) are handled as narrow loads from a 4-byte wide field. This by itself is not enough to create a problem, but when we combine 1. 32-bit wide access to ->remote_port backed by a 16-wide wide load, with 2. inherent difference between litte- and big-endian in how narrow loads need have to be handled (see bpf_ctx_narrow_access_offset), we get inconsistent results for a 2-byte loads from &ctx->remote_port on LE and BE architectures. This in turn makes BPF C code for the common case of 2-byte load from ctx->remote_port not portable. To rectify it, inform the context access converter that remote_port is 2-byte wide field, and only 1-byte loads need to be treated as narrow loads. At the same time, we special-case the 4-byte load from &ctx->remote_port to continue handling it the same way as do today, in order to keep the existing BPF programs working. Fixes: 9a69e2b385f4 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") Signed-off-by: Jakub Sitnicki Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20220319183356.233666-2-jakub@cloudflare.com diff --git a/net/core/filter.c b/net/core/filter.c index 03655f2074ae..a7044e98765e 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -10989,13 +10989,24 @@ static bool sk_lookup_is_valid_access(int off, int size, case bpf_ctx_range(struct bpf_sk_lookup, local_ip4): case bpf_ctx_range_till(struct bpf_sk_lookup, remote_ip6[0], remote_ip6[3]): case bpf_ctx_range_till(struct bpf_sk_lookup, local_ip6[0], local_ip6[3]): - case offsetof(struct bpf_sk_lookup, remote_port) ... - offsetof(struct bpf_sk_lookup, local_ip4) - 1: case bpf_ctx_range(struct bpf_sk_lookup, local_port): case bpf_ctx_range(struct bpf_sk_lookup, ingress_ifindex): bpf_ctx_record_field_size(info, sizeof(__u32)); return bpf_ctx_narrow_access_ok(off, size, sizeof(__u32)); + case bpf_ctx_range(struct bpf_sk_lookup, remote_port): + /* Allow 4-byte access to 2-byte field for backward compatibility */ + if (size == sizeof(__u32)) + return true; + bpf_ctx_record_field_size(info, sizeof(__be16)); + return bpf_ctx_narrow_access_ok(off, size, sizeof(__be16)); + + case offsetofend(struct bpf_sk_lookup, remote_port) ... + offsetof(struct bpf_sk_lookup, local_ip4) - 1: + /* Allow access to zero padding for backward compatibility */ + bpf_ctx_record_field_size(info, sizeof(__u16)); + return bpf_ctx_narrow_access_ok(off, size, sizeof(__u16)); + default: return false; } @@ -11077,6 +11088,11 @@ static u32 sk_lookup_convert_ctx_access(enum bpf_access_type type, sport, 2, target_size)); break; + case offsetofend(struct bpf_sk_lookup, remote_port): + *target_size = 2; + *insn++ = BPF_MOV32_IMM(si->dst_reg, 0); + break; + case offsetof(struct bpf_sk_lookup, local_port): *insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->src_reg, bpf_target_off(struct bpf_sk_lookup_kern,