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=-17.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 A9ABFC06511 for ; Mon, 1 Jul 2019 16:31:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7936420B7C for ; Mon, 1 Jul 2019 16:31:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qPbJ4W83" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728489AbfGAQbJ (ORCPT ); Mon, 1 Jul 2019 12:31:09 -0400 Received: from mail-pg1-f202.google.com ([209.85.215.202]:42825 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727511AbfGAQbJ (ORCPT ); Mon, 1 Jul 2019 12:31:09 -0400 Received: by mail-pg1-f202.google.com with SMTP id d3so7912074pgc.9 for ; Mon, 01 Jul 2019 09:31:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=RrgNUEkDrGeg2elyfbN93BGpRenDb5SclUREHfyGkOk=; b=qPbJ4W83vlHi8ZvryKPlkEaV5gIizAzXVNMIDBw1dcloJMUl7Iga98VDCQxGiDsO4U vJlHok/BCRCYZwgnBN+8R0Gt6Gnnw70EWt4caou+nwU8OT5P6kMClxEZnwNZdsHkoM84 yo1RLTsR0jS5fBNceUqnqModT352JE3BC5znNuMfz2K8SNjopCsMcAxjR7RpX3cxgIFf 7CkfGRDKNN7w+TlZSbHCe9JKZCO72nSbjEImxoNLyiU0w8hFwlQ7x7ahBbXzn2ozkYhv ZFXAVPrLgLS3WCG/cvrcsTqlMCTOxfxOn5F6VWbTxWKMMXPiqCPhK4dozQGplj0iZQwY P/vQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RrgNUEkDrGeg2elyfbN93BGpRenDb5SclUREHfyGkOk=; b=T2siUf2XQSWAou200fjUiSv2FOQCy6cqhjmnkPvidtFtFVUe7pun21zQvHEqde51IN dNMUxDIW5rMnYb2cdDM1w6MvgsQLhSS6GYavZPjqWfV8vIAUsoPzHbKrfwOsP54Mtz7w +xAnjNM8B5NbCVuzByDTWRIT960G9hB5W2T1H9sbOKCfl5z9jOjEi6c0H3u5pe/srgt/ 1/wIurufbK+4Hj8eU1d9S/UimTPNXk3j1r5EQ2otT7rTjCsz8Zio8DmDtIB18iFsX6cr +vayA5U7SVuo4yBeaElJXc8Ejf92BcdVzfStFh6HP/bj6dvQJYLCwtlaqqqF1wy/Q5gc QSHw== X-Gm-Message-State: APjAAAVsLRxPn8sNNQQj+Bh1/eyj2+vkUnjzfqTWMWsopzvv248O+0AS iJ2sGO4pT6+3UIJPwoMB4TAsDgkqOSQYE4/sbzgh2gvMzrxwIF2utqJzKMEMJb2By0MD4G2cQ4q QH5KAb7ce4bwKvdYGOPKDfiXFQAgm5HaRcQ1R0L1F+S9VUz0/3Y8Caw== X-Google-Smtp-Source: APXvYqy7lwsM4FjFX4Ti8GdP3wpKVehG8OTkzRPbvMOdSNxFQFMMkfz0dsMy0ZWAZsm1yQKi0/znkbc= X-Received: by 2002:a63:ea0a:: with SMTP id c10mr26554590pgi.426.1561998667762; Mon, 01 Jul 2019 09:31:07 -0700 (PDT) Date: Mon, 1 Jul 2019 09:31:01 -0700 In-Reply-To: <20190701163103.237550-1-sdf@google.com> Message-Id: <20190701163103.237550-2-sdf@google.com> Mime-Version: 1.0 References: <20190701163103.237550-1-sdf@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH bpf-next v2 1/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev , Andrii Nakryiko , Yonghong Song , kernel test robot Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided that it can do a single u64 store into user_ip6[2] instead of two separate u32 ones: # 17: (18) r2 = 0x100000000000000 # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); # 19: (7b) *(u64 *)(r1 +16) = r2 # invalid bpf_context access off=16 size=8 >From the compiler point of view it does look like a correct thing to do, so let's support it on the kernel side. Credit to Andrii Nakryiko for a proper implementation of bpf_ctx_wide_store_ok. Cc: Andrii Nakryiko Cc: Yonghong Song Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") Reported-by: kernel test robot Acked-by: Yonghong Song Acked-by: Andrii Nakryiko Signed-off-by: Stanislav Fomichev --- include/linux/filter.h | 6 ++++++ include/uapi/linux/bpf.h | 4 ++-- net/core/filter.c | 22 ++++++++++++++-------- 3 files changed, 22 insertions(+), 10 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 340f7d648974..3901007e36f1 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) return size <= size_default && (size & (size - 1)) == 0; } +#define bpf_ctx_wide_store_ok(off, size, type, field) \ + (size == sizeof(__u64) && \ + off >= offsetof(type, field) && \ + off + sizeof(__u64) <= offsetofend(type, field) && \ + off % sizeof(__u64) == 0) + #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a396b516a2b2..586867fe6102 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3237,7 +3237,7 @@ struct bpf_sock_addr { __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write. * Stored in network byte order. */ - __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. + __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write. * Stored in network byte order. */ __u32 user_port; /* Allows 4-byte read and write. @@ -3249,7 +3249,7 @@ struct bpf_sock_addr { __u32 msg_src_ip4; /* Allows 1,2,4-byte read an 4-byte write. * Stored in network byte order. */ - __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. + __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write. * Stored in network byte order. */ __bpf_md_ptr(struct bpf_sock *, sk); diff --git a/net/core/filter.c b/net/core/filter.c index dc8534be12fc..5d33f2146dab 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, if (!bpf_ctx_narrow_access_ok(off, size, size_default)) return false; } else { + if (bpf_ctx_wide_store_ok(off, size, + struct bpf_sock_addr, + user_ip6)) + return true; + + if (bpf_ctx_wide_store_ok(off, size, + struct bpf_sock_addr, + msg_src_ip6)) + return true; + if (size != size_default) return false; } @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. * - * It doesn't support SIZE argument though since narrow stores are not - * supported for now. - * * In addition it uses Temporary Field TF (member of struct S) as the 3rd * "register" since two registers available in convert_ctx_access are not * enough: we can't override neither SRC, since it contains value to store, nor @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, * instructions. But we need a temporary place to save pointer to nested * structure whose field we want to store to. */ -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ do { \ int tmp_reg = BPF_REG_9; \ if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, offsetof(S, TF)); \ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ si->dst_reg, offsetof(S, F)); \ - *insn++ = BPF_STX_MEM( \ - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ target_size) \ + OFF); \ @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, TF) \ do { \ if (type == BPF_WRITE) { \ - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ - TF); \ + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ + OFF, TF); \ } else { \ SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ S, NS, F, NF, SIZE, OFF); \ -- 2.22.0.410.gd8fdbe21b5-goog