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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32F9AEE4996 for ; Mon, 21 Aug 2023 13:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234304AbjHUNkK (ORCPT ); Mon, 21 Aug 2023 09:40:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232131AbjHUNkI (ORCPT ); Mon, 21 Aug 2023 09:40:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A798CB1 for ; Mon, 21 Aug 2023 06:40:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 438E263768 for ; Mon, 21 Aug 2023 13:40:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B0C3C433C8; Mon, 21 Aug 2023 13:40:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692625205; bh=robD6Qvk7RBLuzCXc8ksn5wD90WLafDnKkZgfTSvZWk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dzPIWunafzRrjSKU8cDGbYfniv4IKoMSXQtoXkjsBsHp5xJMcwvY5EiKRGRgPqY22 rKVDJliSVOTpJZs4yAKytOujv5/k9Z9g7xgfXL1Aut5zpPaE8tMzS6qCchLTre0Xeb HUNAGgrDDnvJE8ENKz7NpTvIrSrGpE53XKwXXoogCKMo1N9xZ4CyKP3Yc/AdhNglkr H7n53YWlr0zpit7VYnD3Ce3l7AtBBjT9cxkddYp0ouXWekEgAF4HIq6soaOXnJJAMX RnlbXu4cg7t+LH70VpN5ZnlZ+f5QeYA79Gwed1Lyfx3Yx1vQGb4c4zbYjOsmqLNajC HQqWmYk5SvUOg== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 10D2540722; Mon, 21 Aug 2023 10:40:02 -0300 (-03) Date: Mon, 21 Aug 2023 10:40:02 -0300 From: Arnaldo Carvalho de Melo To: Ian Rogers Cc: Adrian Hunter , Jiri Olsa , Namhyung Kim , Linux Kernel Mailing List Subject: Re: [PATCH 1/1] perf bpf_skel augmented_raw_syscalls: Cap the socklen parameter using &= sizeof(saddr) Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Aug 16, 2023 at 03:10:00PM -0700, Ian Rogers escreveu: > On Wed, Aug 16, 2023 at 2:48 PM Arnaldo Carvalho de Melo wrote: > > R2 min value is negative, either use unsigned or 'var &= const' > > processed 22 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 > > -- END PROG LOAD LOG -- > > libbpf: prog 'sys_enter_sendto': failed to load: -13 > > libbpf: failed to load object 'augmented_raw_syscalls_bpf' > > libbpf: failed to load BPF skeleton 'augmented_raw_syscalls_bpf': -13 > > > > So use the suggested &= variant since sizeof(saddr) == 128 bytes. > > Could this be an assert? you mean (removing the change to saddr to make it trigger): diff --git a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c index 9c1d0b271b20f693..521ce2d7357d983c 100644 --- a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c +++ b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c @@ -10,6 +10,16 @@ #include #include +/** + * is_power_of_2() - check if a value is a power of two + * @n: the value to check + * + * Determine whether some value is a power of two, where zero is *not* + * considered a power of two. Return: true if @n is a power of 2, otherwise + * false. + */ +#define is_power_of_2(n) (n != 0 && ((n & (n - 1)) == 0)) + #define MAX_CPUS 4096 // FIXME: These should come from system headers @@ -112,7 +122,10 @@ struct augmented_args_payload { struct { struct augmented_arg arg, arg2; }; - struct sockaddr_storage saddr; + struct { + struct sockaddr_storage real_saddr; + char padding; + } saddr; char __data[sizeof(struct augmented_arg)]; }; }; @@ -187,6 +200,7 @@ int sys_enter_connect(struct syscall_enter_args *args) if (augmented_args == NULL) return 1; /* Failure: don't filter */ + _Static_assert(is_power_of_2(sizeof(augmented_args->saddr)), "sizeof(augmented_args->saddr) needs to be a power of two"); socklen &= sizeof(augmented_args->saddr) - 1; bpf_probe_read(&augmented_args->saddr, socklen, sockaddr_arg); -------------------------------- CLANG /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o util/bpf_skel/augmented_raw_syscalls.bpf.c:203:2: error: static_assert failed due to requirement 'sizeof (augmented_args->saddr) != 0 && ((sizeof (augmented_args->saddr) & (sizeof (augmented_args->saddr) - 1)) == 0)' "sizeof(augmented_args->saddr) needs to be a power of two" _Static_assert(is_power_of_2(sizeof(augmented_args->saddr)), "sizeof(augmented_args->saddr) needs to be a power of two"); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. make[2]: *** [Makefile.perf:1104: /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o] Error 1 make[1]: *** [Makefile.perf:238: sub-make] Error 2 make: *** [Makefile:113: install-bin] Error 2 make: Leaving directory '/var/home/acme/git/perf-tools-next/tools/perf' And here the assert being satisfied: ⬢[acme@toolbox perf-tools-next]$ git diff diff --git a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c index 9c1d0b271b20f693..43549b63b433d81e 100644 --- a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c +++ b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c @@ -10,6 +10,16 @@ #include #include +/** + * is_power_of_2() - check if a value is a power of two + * @n: the value to check + * + * Determine whether some value is a power of two, where zero is *not* + * considered a power of two. Return: true if @n is a power of 2, otherwise + * false. + */ +#define is_power_of_2(n) (n != 0 && ((n & (n - 1)) == 0)) + #define MAX_CPUS 4096 // FIXME: These should come from system headers @@ -187,6 +197,7 @@ int sys_enter_connect(struct syscall_enter_args *args) if (augmented_args == NULL) return 1; /* Failure: don't filter */ + _Static_assert(is_power_of_2(sizeof(augmented_args->saddr)), "sizeof(augmented_args->saddr) needs to be a power of two"); socklen &= sizeof(augmented_args->saddr) - 1; bpf_probe_read(&augmented_args->saddr, socklen, sockaddr_arg); ⬢[acme@toolbox perf-tools-next]$ m make: Entering directory '/var/home/acme/git/perf-tools-next/tools/perf' BUILD: Doing 'make -j32' parallel build INSTALL libsubcmd_headers INSTALL libperf_headers INSTALL libapi_headers INSTALL libbpf_headers CLANG /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o GENSKEL /tmp/build/perf-tools-next/util/bpf_skel/augmented_raw_syscalls.skel.h INSTALL libsymbol_headers CC /tmp/build/perf-tools-next/builtin-trace.o LD /tmp/build/perf-tools-next/perf-in.o LINK /tmp/build/perf-tools-next/perf INSTALL binaries INSTALL tests INSTALL libperf-jvmti.so INSTALL libexec INSTALL perf-archive INSTALL perf-iostat INSTALL strace/groups INSTALL perl-scripts INSTALL python-scripts INSTALL dlfilters INSTALL perf_completion-script INSTALL perf-tip make: Leaving directory '/var/home/acme/git/perf-tools-next/tools/perf' ⬢[acme@toolbox perf-tools-next]$