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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C4682C43140 for ; Wed, 12 May 2021 23:10:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BC4461425 for ; Wed, 12 May 2021 23:10:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235660AbhELXB0 (ORCPT ); Wed, 12 May 2021 19:01:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346997AbhELVpP (ORCPT ); Wed, 12 May 2021 17:45:15 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB553C08C5DB for ; Wed, 12 May 2021 14:33:28 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id y32so19270143pga.11 for ; Wed, 12 May 2021 14:33:28 -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=PVM6js/8x3mcMhIaz4/jpNKgQpvWqEVdFBIwdtNedIM=; b=I9lMtg1gpgSnYIB0xhcTagX1TjXYqb+uzVn+e3/VIlnJN1Cvl8quWLhhAjLxDJPsYJ ql/L6obdzb6SFKaMMqhI5yF705kXATJHejtV5iM+XFmMcnHGuhuG8PiVV8AQ2uHW647M erB3Q9Ykq8kgF/ionzzitP5N3M1Gue6vr6RbU7MjmxAlR9F00z1HUbZpyzyMB3yNOLAP iqStLJLER9pcN9VzynFd4P2IwJjLbCnAUrmk1t3BEi57RwmCpIqB0QPZfJxrifI8ZBzl Zkra/SuL0FVgnsxXkJfwG4xFlGBJ+cBiKyZz+LbzvcumezMIquLSaqH4e9Qk7XQqPb9O zMdA== 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=PVM6js/8x3mcMhIaz4/jpNKgQpvWqEVdFBIwdtNedIM=; b=eFbnZDFCRwJuXaoDn5OKhsLUoDPcPXWE9syrxdnTiaKOE68ZUp6H7pkfsnCUGt5Yd3 DB0BH4zLv/JJcuBjQQ75o+cFCbFzati7nXFIeQo92pRjT0H5my8xsnYf9dmx5V4NJs3l OtKpszz2Izec3uztq/s02SPmAqsoZhubsl7W08Gq8mLjp04Sm/U2zk13zwhlbkW6uosE gIVn+N9YS2I7b923SGEElW3CAXra+j7K99OlGJnuyw902PIBGr12o1T2Yy1gQ/AsJoMF sS3VSSMXBPg+T5VDAGIBAy5v8LcWaM5zegRh80TtvV/9NHlwWzJAhYj/moZ/3+0fgxpC Jw7A== X-Gm-Message-State: AOAM530a2DDG0iGNFXePulaVpeNCVN+cWDRMbP8RhKDFf4dhrDN2V2IV oepIsgBv6FSA3Q1HY7a6NMw= X-Google-Smtp-Source: ABdhPJxMBHqq6oZVnUMtfnCXSZQnrHLwvK2cWlzOKtC4eSYkhV07Kf9wTwZjRwmz/o57vMlL00RyFg== X-Received: by 2002:a17:90b:188f:: with SMTP id mn15mr2273496pjb.219.1620855208484; Wed, 12 May 2021 14:33:28 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.4]) by smtp.gmail.com with ESMTPSA id c128sm609222pfa.189.2021.05.12.14.33.26 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 May 2021 14:33:27 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, andrii@kernel.org, john.fastabend@gmail.com, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v5 bpf-next 15/21] libbpf: Cleanup temp FDs when intermediate sys_bpf fails. Date: Wed, 12 May 2021 14:32:50 -0700 Message-Id: <20210512213256.31203-16-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20210512213256.31203-1-alexei.starovoitov@gmail.com> References: <20210512213256.31203-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Alexei Starovoitov Fix loader program to close temporary FDs when intermediate sys_bpf command fails. Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko --- tools/lib/bpf/bpf_gen_internal.h | 1 + tools/lib/bpf/gen_loader.c | 48 +++++++++++++++++++++++++++++--- 2 files changed, 45 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h index f42a55efd559..615400391e57 100644 --- a/tools/lib/bpf/bpf_gen_internal.h +++ b/tools/lib/bpf/bpf_gen_internal.h @@ -15,6 +15,7 @@ struct bpf_gen { void *data_cur; void *insn_start; void *insn_cur; + ssize_t cleanup_label; __u32 nr_progs; __u32 nr_maps; int log_level; diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index 585c672cc53e..bf61a046bc77 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -97,8 +97,36 @@ static void bpf_gen__emit2(struct bpf_gen *gen, struct bpf_insn insn1, struct bp void bpf_gen__init(struct bpf_gen *gen, int log_level) { + size_t stack_sz = sizeof(struct loader_stack); + int i; + gen->log_level = log_level; + /* save ctx pointer into R6 */ bpf_gen__emit(gen, BPF_MOV64_REG(BPF_REG_6, BPF_REG_1)); + + /* bzero stack */ + bpf_gen__emit(gen, BPF_MOV64_REG(BPF_REG_1, BPF_REG_10)); + bpf_gen__emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -stack_sz)); + bpf_gen__emit(gen, BPF_MOV64_IMM(BPF_REG_2, stack_sz)); + bpf_gen__emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0)); + bpf_gen__emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel)); + + /* jump over cleanup code */ + bpf_gen__emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, + /* size of cleanup code below */ + (stack_sz / 4) * 3 + 2)); + + /* remember the label where all error branches will jump to */ + gen->cleanup_label = gen->insn_cur - gen->insn_start; + /* emit cleanup code: close all temp FDs */ + for (i = 0; i < stack_sz; i += 4) { + bpf_gen__emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -stack_sz + i)); + bpf_gen__emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 1)); + bpf_gen__emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close)); + } + /* R7 contains the error code from sys_bpf. Copy it into R0 and exit. */ + bpf_gen__emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7)); + bpf_gen__emit(gen, BPF_EXIT_INSN()); } static int bpf_gen__add_data(struct bpf_gen *gen, const void *data, __u32 size) @@ -177,12 +205,24 @@ static void bpf_gen__emit_sys_bpf(struct bpf_gen *gen, int cmd, int attr, int at bpf_gen__emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); } +static bool is_simm16(__s64 value) +{ + return value == (__s64)(__s16)value; +} + static void bpf_gen__emit_check_err(struct bpf_gen *gen) { - bpf_gen__emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 2)); - bpf_gen__emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7)); - /* TODO: close intermediate FDs in case of error */ - bpf_gen__emit(gen, BPF_EXIT_INSN()); + __s64 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 1; + + /* R7 contains result of last sys_bpf command. + * if (R7 < 0) goto cleanup; + */ + if (is_simm16(off)) { + bpf_gen__emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, off)); + } else { + gen->error = -ERANGE; + bpf_gen__emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, -1)); + } } /* reg1 and reg2 should not be R1 - R5. They can be R0, R6 - R10 */ -- 2.30.2