From patchwork Fri Jun 28 23:10:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 1124606 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="G1HGo98N"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45bCDb3sz9z9s5c for ; Sat, 29 Jun 2019 09:10:54 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726787AbfF1XKx (ORCPT ); Fri, 28 Jun 2019 19:10:53 -0400 Received: from mail-pg1-f202.google.com ([209.85.215.202]:45195 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726631AbfF1XKx (ORCPT ); Fri, 28 Jun 2019 19:10:53 -0400 Received: by mail-pg1-f202.google.com with SMTP id n7so3900836pgr.12 for ; Fri, 28 Jun 2019 16:10:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=H1uw8GNHqdne1YqmW30hQmg7ehvjJ07bgavin0v97FA=; b=G1HGo98N06/C96ASXTRQ8Z8DwfpQ4rC88TZvh6R7AuL8Bb0uMCA64FgFwfWI2OrlW/ 5ZYxVu3fBdgzsYk082oSaxiDQ7WI6m7GR2IhKVgd296VQNlZa+BcFhDzjqyLQLnd0w+L M57d/1psVlxo/oszPG70J9CMX+jmcJJ2gLUQvTiB6ip2Q+CvmJTQGqXLGB1ixAhRqUKT F3Mr4ZAHddLFcizilTx9AAtfz2fjcweEKNNWvgfpTQFGZe7ni46zS41PKUYchuqyinH6 pRRYoYS+1iYxRq1UBr2W3VIwYAixrTKZoj1rPtrdgkeHvlKwALMvpzQHM+axZXLsgE9q U8OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=H1uw8GNHqdne1YqmW30hQmg7ehvjJ07bgavin0v97FA=; b=fiepx2xy9OHibjsygJj2kmd3eD9eMjbv9v8hxfCsoBdtfA52iKDDY5IlKELQORkz9u Ex47FBcg1+M8BBBhV2uJa6SBChri2Rg7F3PgrrygQUOXKHIqjwGPxxcgAES+vHUPxFNe wfk1SiF30KEh7JuDlEty4QTERkx/qhe/d/dZPhRfX3Q89hbO6MVlPfGliGUIKha059Np q1UadxxWBmjfp/7Q707pGmyWRFjOSM10eIthasXND6Yh9teYqzO0rwBr+vdoXVfef3EG x3sz8hDkpAZDWGTMSHCqHxLWyKXEu24yUuXD78QRvDddrntmV0WN8h/LxVG3Pcij7nnm dT0g== X-Gm-Message-State: APjAAAXSc4uPs5au0QqKC2DsxXAg1KMBv+ZMWCbpk36cwSyOxFGN/WyM mWcJOIQt9di2LKsVJHO9+RiOKYv/WDSBvoR8/IAAcGuOrOSiTE05nLL/YcY/CTj/6oOd1b39flL zyfEPZYAWO0SopxZCv3B28jWYoR9Uk7RMs8ql3ZVdOn3Qfn/4GuImgQ== X-Google-Smtp-Source: APXvYqzn1y/EUNmYcU6bEtZmjhaAhzm9/gCbpGaC5ql1JodiKRqRZXv/A3SZQLptiFW84eM3ykNpngA= X-Received: by 2002:a63:a61:: with SMTP id z33mr11668815pgk.154.1561763451833; Fri, 28 Jun 2019 16:10:51 -0700 (PDT) Date: Fri, 28 Jun 2019 16:10:48 -0700 Message-Id: <20190628231049.22149-1-sdf@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH bpf-next 1/2] 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 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 Signed-off-by: Stanislav Fomichev Acked-by: Yonghong Song Acked-by: Andrii Nakryiko --- include/linux/filter.h | 6 ++++++ net/core/filter.c | 22 ++++++++++++++-------- 2 files changed, 20 insertions(+), 8 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/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); \