From nobody Mon Sep 29 22:44:04 2025 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 DA927C00140 for ; Mon, 15 Aug 2022 23:56:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355602AbiHOX45 (ORCPT ); Mon, 15 Aug 2022 19:56:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355260AbiHOXvp (ORCPT ); Mon, 15 Aug 2022 19:51:45 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 010B0915DA; Mon, 15 Aug 2022 13:16:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9B4A7B81135; Mon, 15 Aug 2022 20:16:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFF27C433C1; Mon, 15 Aug 2022 20:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660594581; bh=1K9xXNSG9/yXeEpePkN/PftOVnjSIAgTNM/gGLaMToY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lDQjwlgnBh/v1YPAFVbwEeHHCGGaB8NiNmWGfeNydjDLuAypNl0LvmNGTTmWSYnd8 cYixUDqkQhtsnpYTb3m6o91OHXT2GUZWPYMR+yc6IoQq9fHrQMaJVMyCsD1SoASV6w y2LFabK2gdIZiXRTDwJ4u4zRNiAhUeVwWn+l9n8A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anquan Wu , Andrii Nakryiko , Sasha Levin Subject: [PATCH 5.19 0494/1157] libbpf: Fix the name of a reused map Date: Mon, 15 Aug 2022 19:57:30 +0200 Message-Id: <20220815180459.411957333@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anquan Wu [ Upstream commit bf3f00378524adae16628cbadbd11ba7211863bb ] BPF map name is limited to BPF_OBJ_NAME_LEN. A map name is defined as being longer than BPF_OBJ_NAME_LEN, it will be truncated to BPF_OBJ_NAME_LEN when a userspace program calls libbpf to create the map. A pinned map also generates a path in the /sys. If the previous program wanted to reuse the map=EF=BC=8C it can not get bpf_map by name, because the name of the map is only partially the same as the name which get from pinned path. The syscall information below show that map name "process_pinned_map" is truncated to "process_pinned_". bpf(BPF_OBJ_GET, {pathname=3D"/sys/fs/bpf/process_pinned_map", bpf_fd=3D0, file_flags=3D0}, 144) =3D -1 ENOENT (No such file or direct= ory) bpf(BPF_MAP_CREATE, {map_type=3DBPF_MAP_TYPE_HASH, key_size=3D4, value_size=3D4,max_entries=3D1024, map_flags=3D0, inner_map_fd=3D0, map_name=3D"process_pinned_",map_ifindex=3D0, btf_fd=3D3, btf_key_type_= id=3D6, btf_value_type_id=3D10,btf_vmlinux_value_type_id=3D0}, 72) =3D 4 This patch check that if the name of pinned map are the same as the actual name for the first (BPF_OBJ_NAME_LEN - 1), bpf map still uses the name which is included in bpf object. Fixes: 26736eb9a483 ("tools: libbpf: allow map reuse") Signed-off-by: Anquan Wu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/OSZP286MB1725CEA1C95C5CB8E7CCC53FB8869@OS= ZP286MB1725.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b9245bf688fa..5b9b42ab7aa0 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4327,7 +4327,7 @@ int bpf_map__set_autocreate(struct bpf_map *map, bool= autocreate) int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info =3D {}; - __u32 len =3D sizeof(info); + __u32 len =3D sizeof(info), name_len; int new_fd, err; char *new_name; =20 @@ -4337,7 +4337,12 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) if (err) return libbpf_err(err); =20 - new_name =3D strdup(info.name); + name_len =3D strlen(info.name); + if (name_len =3D=3D BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name,= name_len) =3D=3D 0) + new_name =3D strdup(map->name); + else + new_name =3D strdup(info.name); + if (!new_name) return libbpf_err(-errno); =20 --=20 2.35.1