From patchwork Tue Oct 12 13:59:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 12552797 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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46D12C433FE for ; Tue, 12 Oct 2021 13:59:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DF7461167 for ; Tue, 12 Oct 2021 13:59:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237155AbhJLOBx (ORCPT ); Tue, 12 Oct 2021 10:01:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237114AbhJLOBu (ORCPT ); Tue, 12 Oct 2021 10:01:50 -0400 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1338DC06174E for ; Tue, 12 Oct 2021 06:59:49 -0700 (PDT) Received: by mail-wr1-x430.google.com with SMTP id v17so67209849wrv.9 for ; Tue, 12 Oct 2021 06:59:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3TJptnN4GzzzsUZvyAiZp6iIaMylBdItWw9O0Dv3HnA=; b=cEXX6Mwrzs0vcm+TK38bYcoPrMHAs0fVD4jmEKoOLPPaGOcW9Qr6Zup4q7Kga2P0X7 QVnbk5vBa9BvvMXBXCaROYb02HihhCiVW9yB4XJ2PH8I0Rn7AwAjlGsKBNnGvS6LxHRH q6D1e7luYHHtp4LCyC5fDwreOAtgoseaEWeec= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3TJptnN4GzzzsUZvyAiZp6iIaMylBdItWw9O0Dv3HnA=; b=VBLygRGwd/RskG5P2KIRnLM7sJmHK7dSPwv9SvC8O3bmLQJoSnIogQiq6/ZpJnUAoN BP9ctEI/t17Z5P8ygFQKirJkrSGU60Sx+noX1qe3+y4ujQ2GLDe8CNeHGA7vPSic35Bn 3diGowuOMZKaQjeAbigjvTpkxU/9hKoR9f3lfNYIJiu3vE9bquPEHJLvv1PvUQsAOct9 Xb6DBxTMSDDwttYrx37/2ooh84TNbe66A3CYzXtE9py9C1dK+i6nsAEW+/qLBIfF6zRZ MP2DtSlcQWBoDzYnu/N9+yS0a38jVmp/fty91PEjJsWsXXyafsWAtwPiHjzruS/mpdgX Id5Q== X-Gm-Message-State: AOAM533ChSN9JtBuszCNhU/uCLTpL3mh3KRuYHQmucaG2NJC3Bzw6U+t 38qQOOtCOe1BpYJvwshlJlJ7+g== X-Google-Smtp-Source: ABdhPJwuWlvoXE01sklUceayFwJNHshBmOnMKqtYiLDNpo/fCBYUw+NZfYsR4cYPv0+2ghqgOm2LLA== X-Received: by 2002:adf:e0c1:: with SMTP id m1mr32554707wri.241.1634047187605; Tue, 12 Oct 2021 06:59:47 -0700 (PDT) Received: from antares.. (d.5.b.3.f.b.d.4.c.0.9.7.6.8.3.1.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff:1386:790c:4dbf:3b5d]) by smtp.gmail.com with ESMTPSA id o6sm14875894wri.49.2021.10.12.06.59.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Oct 2021 06:59:47 -0700 (PDT) From: Lorenz Bauer To: nicolas.dichtel@6wind.com, luke.r.nels@gmail.com, Jonathan Corbet , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , "David S. Miller" , Jakub Kicinski Cc: kernel-team@cloudflare.com, Lorenz Bauer , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH v2 4/4] bpf: export bpf_jit_current Date: Tue, 12 Oct 2021 14:59:35 +0100 Message-Id: <20211012135935.37054-5-lmb@cloudflare.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211012135935.37054-1-lmb@cloudflare.com> References: <20211012135935.37054-1-lmb@cloudflare.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Expose bpf_jit_current as a read only value via sysctl. Signed-off-by: Lorenz Bauer --- Documentation/admin-guide/sysctl/net.rst | 6 ++++++ include/linux/filter.h | 1 + kernel/bpf/core.c | 3 +-- net/core/sysctl_net_core.c | 24 ++++++++++++++++++++++++ 4 files changed, 32 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index 4150f74c521a..524e7db8d53f 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -123,6 +123,12 @@ compiler in order to reject unprivileged JIT requests once it has been surpassed. bpf_jit_limit contains the value of the global limit in bytes. +bpf_jit_current +--------------- + +The amount of JIT memory currently allocated, in bytes. JITing of +unprivileged BPF is rejected if this value is above bpf_jit_limit. + dev_weight ---------- diff --git a/include/linux/filter.h b/include/linux/filter.h index 8231a6a257f6..42c543a21cd8 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1051,6 +1051,7 @@ extern int bpf_jit_harden; extern int bpf_jit_kallsyms; extern long bpf_jit_limit; extern long bpf_jit_limit_max; +extern atomic_long_t bpf_jit_current; typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ab84b3816339..12aedab09222 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -526,6 +526,7 @@ int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); int bpf_jit_harden __read_mostly; long bpf_jit_limit __read_mostly; long bpf_jit_limit_max __read_mostly; +atomic_long_t bpf_jit_current __read_mostly; static void bpf_prog_ksym_set_addr(struct bpf_prog *prog) @@ -801,8 +802,6 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, return slot; } -static atomic_long_t bpf_jit_current; - /* Can be overridden by an arch's JIT compiler if it has a custom, * dedicated BPF backend memory area, or if neither of the two * below apply. diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 5f88526ad61c..78603f561482 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -307,6 +308,22 @@ proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write, return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); } + +static int proc_bpf_jit_current(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + long curr = atomic_long_read(&bpf_jit_current) << PAGE_SHIFT; + struct ctl_table ctl_entry = { + .data = &curr, + .maxlen = sizeof(long), + }; + + + if (!capable(CAP_SYS_ADMIN) || write) + return -EPERM; + + return proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos); +} #endif static struct ctl_table net_core_table[] = { @@ -421,6 +438,13 @@ static struct ctl_table net_core_table[] = { .extra1 = &long_one, .extra2 = &bpf_jit_limit_max, }, + { + .procname = "bpf_jit_current", + .data = &bpf_jit_current, + .maxlen = sizeof(long), + .mode = 0400, + .proc_handler = proc_bpf_jit_current, + }, #endif { .procname = "netdev_tstamp_prequeue",