From patchwork Wed Oct 21 18:20:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 11849585 X-Patchwork-Delegate: bpf@iogearbox.net 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 3D4E4C388F9 for ; Wed, 21 Oct 2020 18:20:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 999E122460 for ; Wed, 21 Oct 2020 18:20:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nm+z7io4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504010AbgJUSUX (ORCPT ); Wed, 21 Oct 2020 14:20:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503991AbgJUSUU (ORCPT ); Wed, 21 Oct 2020 14:20:20 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 710B9C0613CE; Wed, 21 Oct 2020 11:20:20 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id a17so1591964pju.1; Wed, 21 Oct 2020 11:20:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=DuW+ZJ7V0jmdNv0h6ocl0HA+XhmKiKl5KtvsemfeKbg=; b=nm+z7io4EjpKYTd+xgnD0eqOZMy8B76SkkHGfxEuYD7x5tLbqP6QSqIVxN3a/C0Azt FgmD9AgqPuSUg9z93/etdYkZ3ppFFJTtvns4RQH+p5zowoTy5BAL7iOqLUg/F3VBxIRy OAm/lHfK0OjaJBn54RJqfWWlsR95z1pJEWC/00pUHYQ2T3Tdt6ZN3Sq07jz10pJ5u3JY Jp4Qh5Fe+8DycWAeRy4MufdCdyOy/4994jNRHpbkgJHu4nWvpr4+Z1bzfwk7rDcdqyij hgBoSjiu3x4f7c19MIoKr5qNHAapNZqBtJBimHLlmc/jP3xwZacGRgWh55SrtUyfkz0b yZPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=DuW+ZJ7V0jmdNv0h6ocl0HA+XhmKiKl5KtvsemfeKbg=; b=I1Mts597/plsEzmflhETo32NIz0AShyHjWg78RM+A5BCQ61wX9CJ3x+yDak8eRx5Eo xmBLvVsYDpuD42iltjFsChEVlZYw50rjjfzoEMSk/oJPSV30r7qBdm0B9CD82K5o2IJi wKiSETMkqnqDSslr0tU8PjrzXzUcV4HuRf3mbZzSgloUd43+JTOt4knf8JefFETZOwNP 4/ZsDTQfImG9czCRVCX0Ju9vfLbcc76ajR9R242rps4obfVNcB87T06ZRdbdLJcJm74q KTTZQCT+gHj96W381YW+Miu8BuwLb3ggIlc3QWpY+3gdI9HRs4jibxwXB3N+onErr1g1 yAHQ== X-Gm-Message-State: AOAM530xBu1cMUfzVwGETQUYcMdf8kuNqMghh2M/zimSKfIJyVPK/fIn zt0wTyMfiPov7zK/9L5RZzs= X-Google-Smtp-Source: ABdhPJxHS/urP7j9OahNP9rNEDVW/D4MBYb2peAAcQAqA2pT9/Qj0TJK4T+NEkMY+X+N6ygsRztdvA== X-Received: by 2002:a17:90a:3f82:: with SMTP id m2mr4416256pjc.222.1603304419999; Wed, 21 Oct 2020 11:20:19 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.7]) by smtp.gmail.com with ESMTPSA id v3sm2618672pfu.165.2020.10.21.11.20.18 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Oct 2020 11:20:19 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, john.fastabend@gmail.com, jolsa@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH bpf-next 1/3] bpf: Support for pointers beyond pkt_end. Date: Wed, 21 Oct 2020 11:20:13 -0700 Message-Id: <20201021182015.39000-2-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20201021182015.39000-1-alexei.starovoitov@gmail.com> References: <20201021182015.39000-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov This patch adds the verifier support to recognize inlined branch conditions. The LLVM knows that the branch evaluates to the same value, but the verifier couldn't track it. Hence causing valid programs to be rejected. The potential LLVM workaround: https://reviews.llvm.org/D87428 can have undesired side effects, since LLVM doesn't know that skb->data/data_end are being compared. LLVM has to introduce extra boolean variable and use inline_asm trick to force easier for the verifier assembly. Instead teach the verifier to recognize that r1 = skb->data; r1 += 10; r2 = skb->data_end; if (r1 > r2) { here r1 points beyond packet_end and subsequent if (r1 > r2) // always evaluates to "true". } Signed-off-by: Alexei Starovoitov Reported-by: kernel test robot --- include/linux/bpf_verifier.h | 2 +- kernel/bpf/verifier.c | 131 +++++++++++++++++++++++++++++------ 2 files changed, 110 insertions(+), 23 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index e83ef6f6bf43..306869d4743b 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -45,7 +45,7 @@ struct bpf_reg_state { enum bpf_reg_type type; union { /* valid when type == PTR_TO_PACKET */ - u16 range; + int range; /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE | * PTR_TO_MAP_VALUE_OR_NULL diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 39d7f44e7c92..303c5fc1701b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2739,7 +2739,9 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, regno); return -EACCES; } - err = __check_mem_access(env, regno, off, size, reg->range, + + err = reg->range < 0 ? -EINVAL : + __check_mem_access(env, regno, off, size, reg->range, zero_size_allowed); if (err) { verbose(env, "R%d offset is outside of the packet\n", regno); @@ -4687,6 +4689,32 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) __clear_all_pkt_pointers(env, vstate->frame[i]); } +enum { + AT_PKT_END = -1, + BEYOND_PKT_END = -2, +}; + +static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open) +{ + struct bpf_func_state *state = vstate->frame[vstate->curframe]; + struct bpf_reg_state *reg = &state->regs[regn]; + + if (reg->type != PTR_TO_PACKET) + /* PTR_TO_PACKET_META is not supported yet */ + return; + + /* The 'reg' is pkt > pkt_end or pkt >= pkt_end. + * How far beyond pkt_end it goes is unknown. + * if (!range_open) it's the case of pkt >= pkt_end + * if (range_open) it's the case of pkt > pkt_end + * hence this pointer is at least 1 byte bigger than pkt_end + */ + if (range_open) + reg->range = BEYOND_PKT_END; + else + reg->range = AT_PKT_END; +} + static void release_reg_references(struct bpf_verifier_env *env, struct bpf_func_state *state, int ref_obj_id) @@ -6697,7 +6725,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) static void __find_good_pkt_pointers(struct bpf_func_state *state, struct bpf_reg_state *dst_reg, - enum bpf_reg_type type, u16 new_range) + enum bpf_reg_type type, int new_range) { struct bpf_reg_state *reg; int i; @@ -6722,8 +6750,7 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, enum bpf_reg_type type, bool range_right_open) { - u16 new_range; - int i; + int new_range, i; if (dst_reg->off < 0 || (dst_reg->off == 0 && range_right_open)) @@ -6974,6 +7001,69 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, return is_branch64_taken(reg, val, opcode); } +static int flip_opcode(u32 opcode) +{ + /* How can we transform "a b" into "b a"? */ + static const u8 opcode_flip[16] = { + /* these stay the same */ + [BPF_JEQ >> 4] = BPF_JEQ, + [BPF_JNE >> 4] = BPF_JNE, + [BPF_JSET >> 4] = BPF_JSET, + /* these swap "lesser" and "greater" (L and G in the opcodes) */ + [BPF_JGE >> 4] = BPF_JLE, + [BPF_JGT >> 4] = BPF_JLT, + [BPF_JLE >> 4] = BPF_JGE, + [BPF_JLT >> 4] = BPF_JGT, + [BPF_JSGE >> 4] = BPF_JSLE, + [BPF_JSGT >> 4] = BPF_JSLT, + [BPF_JSLE >> 4] = BPF_JSGE, + [BPF_JSLT >> 4] = BPF_JSGT + }; + return opcode_flip[opcode >> 4]; +} + +static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg, + u8 opcode) +{ + struct bpf_reg_state *pkt_end, *pkt; + + if (src_reg->type == PTR_TO_PACKET_END) { + pkt_end = src_reg; + pkt = dst_reg; + } else if (dst_reg->type == PTR_TO_PACKET_END) { + pkt_end = dst_reg; + pkt = src_reg; + opcode = flip_opcode(opcode); + } else { + return -1; + } + + if (pkt->range >= 0) + return -1; + + switch (opcode) { + case BPF_JLE: + /* pkt <= pkt_end */ + fallthrough; + case BPF_JGT: + /* pkt > pkt_end */ + if (pkt->range == BEYOND_PKT_END) + /* pkt has at last one extra byte beyond pkt_end */ + return opcode == BPF_JGT; + break; + case BPF_JLT: + /* pkt < pkt_end */ + fallthrough; + case BPF_JGE: + /* pkt >= pkt_end */ + if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END) + return opcode == BPF_JGE; + break; + } + return -1; +} + /* Adjusts the register min/max values in the case that the dst_reg is the * variable register that we are working on, and src_reg is a constant or we're * simply doing a BPF_K check. @@ -7137,23 +7227,7 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, u64 val, u32 val32, u8 opcode, bool is_jmp32) { - /* How can we transform "a b" into "b a"? */ - static const u8 opcode_flip[16] = { - /* these stay the same */ - [BPF_JEQ >> 4] = BPF_JEQ, - [BPF_JNE >> 4] = BPF_JNE, - [BPF_JSET >> 4] = BPF_JSET, - /* these swap "lesser" and "greater" (L and G in the opcodes) */ - [BPF_JGE >> 4] = BPF_JLE, - [BPF_JGT >> 4] = BPF_JLT, - [BPF_JLE >> 4] = BPF_JGE, - [BPF_JLT >> 4] = BPF_JGT, - [BPF_JSGE >> 4] = BPF_JSLE, - [BPF_JSGT >> 4] = BPF_JSLT, - [BPF_JSLE >> 4] = BPF_JSGE, - [BPF_JSLT >> 4] = BPF_JSGT - }; - opcode = opcode_flip[opcode >> 4]; + opcode = flip_opcode(opcode); /* This uses zero as "not present in table"; luckily the zero opcode, * BPF_JA, can't get here. */ @@ -7334,6 +7408,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_data' > pkt_end, pkt_meta' > pkt_data */ find_good_pkt_pointers(this_branch, dst_reg, dst_reg->type, false); + mark_pkt_end(other_branch, insn->dst_reg, true); } else if ((dst_reg->type == PTR_TO_PACKET_END && src_reg->type == PTR_TO_PACKET) || (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && @@ -7341,6 +7416,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_end > pkt_data', pkt_data > pkt_meta' */ find_good_pkt_pointers(other_branch, src_reg, src_reg->type, true); + mark_pkt_end(this_branch, insn->src_reg, false); } else { return false; } @@ -7353,6 +7429,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_data' < pkt_end, pkt_meta' < pkt_data */ find_good_pkt_pointers(other_branch, dst_reg, dst_reg->type, true); + mark_pkt_end(this_branch, insn->dst_reg, false); } else if ((dst_reg->type == PTR_TO_PACKET_END && src_reg->type == PTR_TO_PACKET) || (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && @@ -7360,6 +7437,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_end < pkt_data', pkt_data > pkt_meta' */ find_good_pkt_pointers(this_branch, src_reg, src_reg->type, false); + mark_pkt_end(other_branch, insn->src_reg, true); } else { return false; } @@ -7372,6 +7450,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */ find_good_pkt_pointers(this_branch, dst_reg, dst_reg->type, true); + mark_pkt_end(other_branch, insn->dst_reg, false); } else if ((dst_reg->type == PTR_TO_PACKET_END && src_reg->type == PTR_TO_PACKET) || (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && @@ -7379,6 +7458,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */ find_good_pkt_pointers(other_branch, src_reg, src_reg->type, false); + mark_pkt_end(this_branch, insn->src_reg, true); } else { return false; } @@ -7391,6 +7471,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */ find_good_pkt_pointers(other_branch, dst_reg, dst_reg->type, false); + mark_pkt_end(this_branch, insn->dst_reg, true); } else if ((dst_reg->type == PTR_TO_PACKET_END && src_reg->type == PTR_TO_PACKET) || (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && @@ -7398,6 +7479,7 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */ find_good_pkt_pointers(this_branch, src_reg, src_reg->type, true); + mark_pkt_end(other_branch, insn->src_reg, false); } else { return false; } @@ -7497,6 +7579,10 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, src_reg->var_off.value, opcode, is_jmp32); + } else if (reg_is_pkt_pointer_any(dst_reg) && + reg_is_pkt_pointer_any(src_reg) && + !is_jmp32) { + pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode); } if (pred >= 0) { @@ -7505,7 +7591,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, */ if (!__is_pointer_value(false, dst_reg)) err = mark_chain_precision(env, insn->dst_reg); - if (BPF_SRC(insn->code) == BPF_X && !err) + if (BPF_SRC(insn->code) == BPF_X && !err && + !__is_pointer_value(false, src_reg)) err = mark_chain_precision(env, insn->src_reg); if (err) return err; From patchwork Wed Oct 21 18:20:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 11849589 X-Patchwork-Delegate: bpf@iogearbox.net 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 513A6C388F9 for ; Wed, 21 Oct 2020 18:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFA0E22472 for ; Wed, 21 Oct 2020 18:20:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ky77SRCA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504012AbgJUSUX (ORCPT ); Wed, 21 Oct 2020 14:20:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504008AbgJUSUW (ORCPT ); Wed, 21 Oct 2020 14:20:22 -0400 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46D60C0613CF; Wed, 21 Oct 2020 11:20:22 -0700 (PDT) Received: by mail-pg1-x543.google.com with SMTP id o3so1953195pgr.11; Wed, 21 Oct 2020 11:20:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=C49i2eC03EUjvenOyg50V4AuCt+6TtwxmRPvVIVD7zc=; b=ky77SRCAJ5qy62yCMqMbGQAopzp8GIDYUHXIL/MKvktTnuJDNp31Rye4+HTo7vWFRL Ptr1zLYiAGBd/Vw0M59NqVZyTuCu921UKeJnvtHiY6+MfKGVAwjBLSnvwH+kcALTez2T kxvBxPguZw0u4tpUmu885GCHfR0xx1ux7ZUS1+kdJLAEBvAmktdEJuR5PFVtx9WiedwT LkfOAz+W7ttknAX7/eSJH3T0czd0EkANKe98364xLT+YOR2r/ijGTSaFbnqyIrO+7cpB G7pC6UogXCUjWP2P58Ud66xMq1ytjCV/Ccye5EFXB/E+JHAiXgjXwyFUWMg/Cllu6YeW f3kw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=C49i2eC03EUjvenOyg50V4AuCt+6TtwxmRPvVIVD7zc=; b=coLcix4M6D4XQwhzdkmM1qmh42tFQkPMuu/UUCyRxfjpuGUXkUuT5uoeSeZPkvnok8 lkZZ5yiR7VXEsfLN0OoFUPvcpfm/qeKAr84xqhs6E5oXX8KVxc0IQtwdjp7fdUbrx6DR xEsetUAY1gwMw5q/EoG5zMxM+T+FycCrNPKU6zIidSTkemSkVMoowLY038ASGnvSkrg8 VH/eBpBYzgxjKj+Z5Cta10e/Ewq7wOvvhDzOt9IYxLDoOcZYX2/K8ZZ6x5WriCeLV46c fE+yJU/F+6+Ie4rM0Np8JGR2+r9poYstXl12rCEbH+8DjBmTnwx2dSVM/EwSLWxW8dCP XjQw== X-Gm-Message-State: AOAM5329qmCEOYaffhP1hR85nqqBrzefKB/zYJwr4n53JL5AQuUrxwoM yRmkviIA/n9drY+tpgs6K4A= X-Google-Smtp-Source: ABdhPJxax/0zTQxXHwghU5dz91wTTVgkY69LMr/IpMlABc7b5kT5joPbjnfjWR46ML8SEglHnQD0fg== X-Received: by 2002:a62:7d14:0:b029:155:2add:290e with SMTP id y20-20020a627d140000b02901552add290emr4889432pfc.41.1603304421808; Wed, 21 Oct 2020 11:20:21 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.7]) by smtp.gmail.com with ESMTPSA id v3sm2618672pfu.165.2020.10.21.11.20.20 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Oct 2020 11:20:20 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, john.fastabend@gmail.com, jolsa@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH bpf-next 2/3] selftests/bpf: Add skb_pkt_end test Date: Wed, 21 Oct 2020 11:20:14 -0700 Message-Id: <20201021182015.39000-3-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20201021182015.39000-1-alexei.starovoitov@gmail.com> References: <20201021182015.39000-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov Add a test that currently makes LLVM generate assembly code: $ llvm-objdump -S skb_pkt_end.o 0000000000000000 : ; if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) 0: 61 12 50 00 00 00 00 00 r2 = *(u32 *)(r1 + 80) 1: 61 14 4c 00 00 00 00 00 r4 = *(u32 *)(r1 + 76) 2: bf 43 00 00 00 00 00 00 r3 = r4 3: 07 03 00 00 36 00 00 00 r3 += 54 4: b7 01 00 00 00 00 00 00 r1 = 0 5: 2d 23 02 00 00 00 00 00 if r3 > r2 goto +2 6: 07 04 00 00 0e 00 00 00 r4 += 14 ; if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) 7: bf 41 00 00 00 00 00 00 r1 = r4 0000000000000040 : 8: b4 00 00 00 ff ff ff ff w0 = -1 ; if (!(ip = get_iphdr(skb))) 9: 2d 23 05 00 00 00 00 00 if r3 > r2 goto +5 ; proto = ip->protocol; 10: 71 12 09 00 00 00 00 00 r2 = *(u8 *)(r1 + 9) ; if (proto != IPPROTO_TCP) 11: 56 02 03 00 06 00 00 00 if w2 != 6 goto +3 ; if (tcp->dest != 0) 12: 69 12 16 00 00 00 00 00 r2 = *(u16 *)(r1 + 22) 13: 56 02 01 00 00 00 00 00 if w2 != 0 goto +1 ; return tcp->urg_ptr; 14: 69 10 26 00 00 00 00 00 r0 = *(u16 *)(r1 + 38) 0000000000000078 : ; } 15: 95 00 00 00 00 00 00 00 exit Signed-off-by: Alexei Starovoitov --- .../bpf/prog_tests/test_skb_pkt_end.c | 41 ++++++++++++++ .../testing/selftests/bpf/progs/skb_pkt_end.c | 54 +++++++++++++++++++ 2 files changed, 95 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c create mode 100644 tools/testing/selftests/bpf/progs/skb_pkt_end.c diff --git a/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c b/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c new file mode 100644 index 000000000000..cf1215531920 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include +#include +#include "skb_pkt_end.skel.h" + +static int sanity_run(struct bpf_program *prog) +{ + __u32 duration, retval; + int err, prog_fd; + + prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4), + NULL, NULL, &retval, &duration); + if (CHECK(err || retval != 123, "test_run", + "err %d errno %d retval %d duration %d\n", + err, errno, retval, duration)) + return -1; + return 0; +} + +void test_test_skb_pkt_end(void) +{ + struct skb_pkt_end *skb_pkt_end_skel = NULL; + __u32 duration = 0; + int err; + + skb_pkt_end_skel = skb_pkt_end__open_and_load(); + if (CHECK(!skb_pkt_end_skel, "skb_pkt_end_skel_load", "skb_pkt_end skeleton failed\n")) + goto cleanup; + + err = skb_pkt_end__attach(skb_pkt_end_skel); + if (CHECK(err, "skb_pkt_end_attach", "skb_pkt_end attach failed: %d\n", err)) + goto cleanup; + + if (sanity_run(skb_pkt_end_skel->progs.main_prog)) + goto cleanup; + +cleanup: + skb_pkt_end__destroy(skb_pkt_end_skel); +} diff --git a/tools/testing/selftests/bpf/progs/skb_pkt_end.c b/tools/testing/selftests/bpf/progs/skb_pkt_end.c new file mode 100644 index 000000000000..cf6823f42e80 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/skb_pkt_end.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +#define BPF_NO_PRESERVE_ACCESS_INDEX +#include +#include +#include + +#define NULL 0 +#define INLINE __always_inline + +#define skb_shorter(skb, len) ((void *)(long)(skb)->data + (len) > (void *)(long)skb->data_end) + +#define ETH_IPV4_TCP_SIZE (14 + sizeof(struct iphdr) + sizeof(struct tcphdr)) + +static INLINE struct iphdr *get_iphdr(struct __sk_buff *skb) +{ + struct iphdr *ip = NULL; + struct ethhdr *eth; + + if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) + goto out; + + eth = (void *)(long)skb->data; + ip = (void *)(eth + 1); + +out: + return ip; +} + +SEC("classifier/cls") +int main_prog(struct __sk_buff *skb) +{ + struct iphdr *ip = NULL; + struct tcphdr *tcp; + __u8 proto = 0; + + if (!(ip = get_iphdr(skb))) + goto out; + + proto = ip->protocol; + + if (proto != IPPROTO_TCP) + goto out; + + tcp = (void*)(ip + 1); + if (tcp->dest != 0) + goto out; + if (!tcp) + goto out; + + return tcp->urg_ptr; +out: + return -1; +} +char _license[] SEC("license") = "GPL"; From patchwork Wed Oct 21 18:20:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 11849587 X-Patchwork-Delegate: bpf@iogearbox.net 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 33B87C56201 for ; Wed, 21 Oct 2020 18:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B082622473 for ; Wed, 21 Oct 2020 18:20:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="X46oR3eB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503991AbgJUSUY (ORCPT ); Wed, 21 Oct 2020 14:20:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504015AbgJUSUY (ORCPT ); Wed, 21 Oct 2020 14:20:24 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5AC4C0613CE; Wed, 21 Oct 2020 11:20:23 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id l18so1988321pgg.0; Wed, 21 Oct 2020 11:20:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=bQDv4ngMFmZAdWeS/hQnXH5tSvDx9O8/9xskgAUaTrI=; b=X46oR3eBSh2053rRWIWetOLLHKNJC5MrkUFbuZYYQ/Emwu53GxqgsjpFHsP182RTOg tg0Hvs0XgywmeepsO/wM69unwC7S32euFaI92MMaJPUGSOiREUOrVaLG6WIQlg4wZ4Eg Juxh+3c5jU702Tlz3AnQ0niO9BYF93kc5JTFrOvPaOwFgnfa+7y2NR6/VjF/GMLm6mAf ftEgb9SGgARMUdwV9ErhD3Ny4YBz7viLqpCwdlHvElG6EHNMkbl4Na7DMGFsteP5/7xh 5U/Yg73+0qKO61cupIfA7Ic3Q0bx1u1UtQMrJJRd4k93jYE/Ph2xzZjvfo1pcdxSjCqq GuJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=bQDv4ngMFmZAdWeS/hQnXH5tSvDx9O8/9xskgAUaTrI=; b=a7TO4cEiQ1ZM1IZckB7fZVtRCyFDGBzgqLjeHBKJ8dM43sKUU5FF5dDvejGVsDdUQ8 sXueiYJcavQSWTDukHtAo9WwEhDUklwPU6STqJI9AwaaUFoNKtXM/3xmOrXACcmyLUAR KJE8pzlpXyX3LniLwpy5aPcpb6iWtsjClDc1LoDVS5GbaoFjAv5U5Vxqm9Rdvz9dGnbt PKODa1QarQ3HVWqf2XIGdrKLSX13KMfIzWmD+x7YGzUYC52Tw5mIhxbDhzoWywUSgQ93 uDmP330Lj7xwVG2xA6U+YF5AICNh53zAAqU1ia/Gxh0QDMWIt2LC56dv5yNmDbagz2EM cdUw== X-Gm-Message-State: AOAM531fbV59ezJ3zBD4hFju6kNiD2/xjdC+awUcbKyVyPosniKLE/tj 4pRYWLAwbedMobKt/2s9zrkS/zLJYKQWBQ== X-Google-Smtp-Source: ABdhPJxZyxDtbzpG5mUyRqAWvs7NoPaBMFcVzJ7dRJ6jytmimjb6flMakIqqNwVqaAUnCBbIbHg2kQ== X-Received: by 2002:a63:e:: with SMTP id 14mr4635728pga.426.1603304423461; Wed, 21 Oct 2020 11:20:23 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.7]) by smtp.gmail.com with ESMTPSA id v3sm2618672pfu.165.2020.10.21.11.20.21 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Oct 2020 11:20:22 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, john.fastabend@gmail.com, jolsa@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH bpf-next 3/3] selftests/bpf: Add asm tests for pkt vs pkt_end comparison. Date: Wed, 21 Oct 2020 11:20:15 -0700 Message-Id: <20201021182015.39000-4-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20201021182015.39000-1-alexei.starovoitov@gmail.com> References: <20201021182015.39000-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov Add few assembly tests for packet comparison. Signed-off-by: Alexei Starovoitov --- .../testing/selftests/bpf/verifier/ctx_skb.c | 42 +++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/ctx_skb.c b/tools/testing/selftests/bpf/verifier/ctx_skb.c index 2e16b8e268f2..2022c0f2cd75 100644 --- a/tools/testing/selftests/bpf/verifier/ctx_skb.c +++ b/tools/testing/selftests/bpf/verifier/ctx_skb.c @@ -1089,3 +1089,45 @@ .errstr_unpriv = "R1 leaks addr", .result = REJECT, }, +{ + "pkt > pkt_end taken check", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, // 0. r2 = *(u32 *)(r1 + data_end) + offsetof(struct __sk_buff, data_end)), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, // 1. r4 = *(u32 *)(r1 + data) + offsetof(struct __sk_buff, data)), + BPF_MOV64_REG(BPF_REG_3, BPF_REG_4), // 2. r3 = r4 + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 42), // 3. r3 += 42 + BPF_MOV64_IMM(BPF_REG_1, 0), // 4. r1 = 0 + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 2), // 5. if r3 > r2 goto 8 + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 14), // 6. r4 += 14 + BPF_MOV64_REG(BPF_REG_1, BPF_REG_4), // 7. r1 = r4 + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 1), // 8. if r3 > r2 goto 10 + BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_1, 9), // 9. r2 = *(u8 *)(r1 + 9) + BPF_MOV64_IMM(BPF_REG_0, 0), // 10. r0 = 0 + BPF_EXIT_INSN(), // 11. exit + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_SK_SKB, +}, +{ + "pkt_end < pkt taken check", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, // 0. r2 = *(u32 *)(r1 + data_end) + offsetof(struct __sk_buff, data_end)), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, // 1. r4 = *(u32 *)(r1 + data) + offsetof(struct __sk_buff, data)), + BPF_MOV64_REG(BPF_REG_3, BPF_REG_4), // 2. r3 = r4 + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 42), // 3. r3 += 42 + BPF_MOV64_IMM(BPF_REG_1, 0), // 4. r1 = 0 + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 2), // 5. if r3 > r2 goto 8 + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 14), // 6. r4 += 14 + BPF_MOV64_REG(BPF_REG_1, BPF_REG_4), // 7. r1 = r4 + BPF_JMP_REG(BPF_JLT, BPF_REG_2, BPF_REG_3, 1), // 8. if r2 < r3 goto 10 + BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_1, 9), // 9. r2 = *(u8 *)(r1 + 9) + BPF_MOV64_IMM(BPF_REG_0, 0), // 10. r0 = 0 + BPF_EXIT_INSN(), // 11. exit + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_SK_SKB, +},