From nobody Thu Dec 18 08:11:13 2025 Received: from xmbghk7.mail.qq.com (xmbghk7.mail.qq.com [43.163.128.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 605A51865EB; Thu, 5 Dec 2024 12:09:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=43.163.128.46 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733400559; cv=none; b=d5cPuaywYhO8d3HzWKhmsmHZ7fT8peJf9WD94FTTWlkdoQJU/JCHhvvHxr4tttRWxWn5ocGM9aztmj4y03vRPIT9lLzm3oPJWyoNrc5mKUgv5JkW6CnPrPHad853VWNTii4t1klnBsaTJB11KOJno4zzvWqp26XgNxyaGtVWAtg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733400559; c=relaxed/simple; bh=XztYH+cgYnKfDgYZq1P+8+QN2V5rVPrVgnapNtYaZZk=; h=Message-ID:From:To:Cc:Subject:Date:MIME-Version; b=gJbibuSVz4LFNMh1wNnKNrCIjxOV4nPi2yX3cfCkhkvCQ6jhbBN+iTIEC8LR0NejgzINQPhjb0Mn62jxKZFBUSkcI7fhm9/+MUfsHwwaWEglPazxTmvJiiuo0J4C2aOve2b2wgtBEhSo2IB1ya1HG+NHugH7l49OMZU8tbsevVU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foxmail.com; spf=pass smtp.mailfrom=foxmail.com; dkim=pass (1024-bit key) header.d=foxmail.com header.i=@foxmail.com header.b=ClVuixGX; arc=none smtp.client-ip=43.163.128.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foxmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=foxmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=foxmail.com header.i=@foxmail.com header.b="ClVuixGX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1733400552; bh=mlGhZqwkmrQ/Ts0isdmhYpIn2D1BQmWEXIWO5s7bnWw=; h=From:To:Cc:Subject:Date; b=ClVuixGXXOxxGJ6fvf8t4NRdp0SRrGEqew+EWBE5YvLoJ9/ATpULxJMB9Jh8Jb7GC OHz9w4tQGjPsX7vBvjVBmMZM/2OWmnwAZnDbOrWhHjtHxFolOqY0MwgJUhrfNLDz8m BjV9p1AfOxTkkgt+36HdRN8R8bRJ1jfT9o89lBn8= Received: from NUC11-F41.. ([39.156.73.10]) by newxmesmtplogicsvrsza15-1.qq.com (NewEsmtp) with SMTP id 248A54BA; Thu, 05 Dec 2024 20:09:08 +0800 X-QQ-mid: xmsmtpt1733400548t234wh7yd Message-ID: X-QQ-XMAILINFO: NSObNE1Kae7ZUcUS5HLVc9zndADhH79CgWR8Sj4LsQN9WfgdnMi6FDCSxlX4Ys l37dH+6wFOLV3WMRuoJAe7neqDMd+VkZi0tAuCf45Hp8RaCo1ftvy8Drf+rCXolqvCbuCQ0/i2FQ Jy5TwxmvBu5grmNJFDaASqHCtnTb934BRUiHwAxPEGlALpxMAvbs/7CGNSfSFWzG8ocec74yzFAD XKECCHZpg/6HgH6CpX1BzuU1j7MfrryhJ+Sz3MhVt4l0UUA22AkUX4UMU7nPjk27VnKQaIUJ4qIE iL/kHRRi5cluXJKikMtJanvalYAn1N6OAMuxDG7GBJRo6nvflrzRB/vASv+X3iN0m8w4blWujN6N H+9hQpgpm0TyqLDmonbjy1uY4mF0fhAsX5dXHPsWZl1dzDrXrEnt1/vHU0JHtOUewcob0mV1KVhw qokDGTK6XsHiqRE/BhVIx3e64cjemtIJg1L2sHAc9iNm8d77cd9bqqBjiMJeOqWpREgxgTZdm6Jq tFvTRzwkp/bDSicWZNlpZopNTi3p9iaCru0JLJ0HV/SWHnIwCDAtOuj5tGQkimoni1Bbk0n8rLIC FLbxwv5eoP4mZUGSPec98ge7KUIIfu3bGAZlN3/gQwqPNyDSozTTylvYwi0SrV38pod0chQD5GVe zbif9hG2ecjOxZeUx0acxZXuudCina5lfZts1gc2+IsOiwJj34Xksp4qykoBDEYjx/iwzsSz10DV xcXMpY6jMCM7fojGNBH+vZXIk2z/i7o2GO871m/h1ykx91KIUrpKv2f2l6/TIcOfWz78idcT/CGe ZvsxtAzmPirMBacvDNa8d9VzjjxCiuA1WnIUK08wQQvej1I2Kf/8V9r/fbdq87oLnMYZYnaQTQ9X NsUC/wsLDjvc+hJgH88nNOG9OuNRii0FMQuwCRRH+j+d44nY04ejl8Hpw4RNC6naBhI3xFRlDFj+ bAkIWx2oGtgtyhY7Vnqv91IixGkHrNiabzwTYgmSU= X-QQ-XMRINFO: OD9hHCdaPRBwq3WW+NvGbIU= From: Rong Tao To: qmo@kernel.org, ast@kernel.org, daniel@iogearbox.net, rongtao@cestc.cn Cc: Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , bpf@vger.kernel.org (open list:BPF [TOOLING] (bpftool)), linux-kernel@vger.kernel.org (open list) Subject: [PATCH bpf-next v3] bpftool: Fix gen object segfault Date: Thu, 5 Dec 2024 20:09:03 +0800 X-OQ-MSGID: <20241205120903.324194-1-rtoax@foxmail.com> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Rong Tao If the input file and output file are the same, the input file is cleared due to opening, resulting in a NULL pointer access by libbpf. $ bpftool gen object prog.o prog.o libbpf: failed to get ELF header for prog.o: invalid `Elf' handle Segmentation fault (gdb) bt #0 0x0000000000450285 in linker_append_elf_syms (linker=3D0x4feda0, ob= j=3D0x7fffffffe100) at linker.c:1296 #1 bpf_linker__add_file (linker=3D0x4feda0, filename=3D= , opts=3D) at linker.c:453 #2 0x000000000040c235 in do_object () #3 0x00000000004021d7 in main () (gdb) frame 0 #0 0x0000000000450285 in linker_append_elf_syms (linker=3D0x4feda0, ob= j=3D0x7fffffffe100) at linker.c:1296 1296 Elf64_Sym *sym =3D symtab->data->d_buf; Signed-off-by: Rong Tao Reviewed-by: Quentin Monnet Tested-by: Quentin Monnet --- v2: https://lore.kernel.org/lkml/tencent_F62A51AFF6A38188D70664421F59349740= 08@qq.com/ v1: https://lore.kernel.org/lkml/tencent_410B8166C55CD2AB64BDEA8E9220461918= 0A@qq.com/ --- tools/bpf/bpftool/gen.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 5a4d3240689e..e5e3e8705cc7 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -1879,6 +1879,8 @@ static int do_object(int argc, char **argv) struct bpf_linker *linker; const char *output_file, *file; int err =3D 0; + int argc_cpy; + char **argv_cpy; =20 if (!REQ_ARGS(2)) { usage(); @@ -1887,6 +1889,17 @@ static int do_object(int argc, char **argv) =20 output_file =3D GET_ARG(); =20 + argc_cpy =3D argc; + argv_cpy =3D argv; + + /* Ensure we don't overwrite any input file */ + while (argc_cpy--) { + if (!strcmp(output_file, *argv_cpy++)) { + p_err("Input and output files cannot be the same"); + goto out; + } + } + linker =3D bpf_linker__new(output_file, NULL); if (!linker) { p_err("failed to create BPF linker instance"); --=20 2.47.1