Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946629AbbHHILk (ORCPT ); Sat, 8 Aug 2015 04:11:40 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53670 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066AbbHHILd (ORCPT ); Sat, 8 Aug 2015 04:11:33 -0400 Date: Sat, 8 Aug 2015 01:10:53 -0700 From: tip-bot for Wang Nan Message-ID: Cc: masami.hiramatsu.pt@hitachi.com, daniel@iogearbox.net, linux-kernel@vger.kernel.org, xiakaixu@huawei.com, lizefan@huawei.com, brendan.d.gregg@gmail.com, hekuang@huawei.com, a.p.zijlstra@chello.nl, wangnan0@huawei.com, mingo@kernel.org, namhyung@kernel.org, acme@redhat.com, tglx@linutronix.de, jolsa@kernel.org, hpa@zytor.com, ast@plumgrid.com, dsahern@gmail.com Reply-To: dsahern@gmail.com, ast@plumgrid.com, jolsa@kernel.org, hpa@zytor.com, tglx@linutronix.de, acme@redhat.com, namhyung@kernel.org, mingo@kernel.org, hekuang@huawei.com, a.p.zijlstra@chello.nl, wangnan0@huawei.com, brendan.d.gregg@gmail.com, lizefan@huawei.com, xiakaixu@huawei.com, linux-kernel@vger.kernel.org, daniel@iogearbox.net, masami.hiramatsu.pt@hitachi.com In-Reply-To: <1435716878-189507-8-git-send-email-wangnan0@huawei.com> References: <1435716878-189507-8-git-send-email-wangnan0@huawei.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] bpf tools: Check endianness and make libbpf fail early Git-Commit-ID: cc4228d57c4c35ae0a29efa1e7687a817dc038d9 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2874 Lines: 91 Commit-ID: cc4228d57c4c35ae0a29efa1e7687a817dc038d9 Gitweb: http://git.kernel.org/tip/cc4228d57c4c35ae0a29efa1e7687a817dc038d9 Author: Wang Nan AuthorDate: Wed, 1 Jul 2015 02:13:55 +0000 Committer: Arnaldo Carvalho de Melo CommitDate: Fri, 7 Aug 2015 10:16:56 -0300 bpf tools: Check endianness and make libbpf fail early Check endianness according to EHDR. Code is taken from tools/perf/util/symbol-elf.c. Libbpf doesn't magically convert missmatched endianness. Even if we swap eBPF instructions to correct byte order, we are unable to deal with endianness in code logical generated by LLVM. Therefore, libbpf should simply reject missmatched ELF object, and let LLVM to create good code. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-8-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/bpf/libbpf.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 36dfbc1..15b3e82 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -192,6 +192,34 @@ errout: return err; } +static int +bpf_object__check_endianness(struct bpf_object *obj) +{ + static unsigned int const endian = 1; + + switch (obj->efile.ehdr.e_ident[EI_DATA]) { + case ELFDATA2LSB: + /* We are big endian, BPF obj is little endian. */ + if (*(unsigned char const *)&endian != 1) + goto mismatch; + break; + + case ELFDATA2MSB: + /* We are little endian, BPF obj is big endian. */ + if (*(unsigned char const *)&endian != 0) + goto mismatch; + break; + default: + return -EINVAL; + } + + return 0; + +mismatch: + pr_warning("Error: endianness mismatch.\n"); + return -EINVAL; +} + static struct bpf_object * __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) { @@ -208,6 +236,8 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) if (bpf_object__elf_init(obj)) goto out; + if (bpf_object__check_endianness(obj)) + goto out; bpf_object__elf_finish(obj); return obj; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/