From nobody Wed Dec 17 09:16:52 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 838A1C32772 for ; Tue, 23 Aug 2022 10:39:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355536AbiHWKjI (ORCPT ); Tue, 23 Aug 2022 06:39:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355281AbiHWKX0 (ORCPT ); Tue, 23 Aug 2022 06:23:26 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66C72A3465; Tue, 23 Aug 2022 02:04:27 -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 9F13FB81C89; Tue, 23 Aug 2022 09:04:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB073C433C1; Tue, 23 Aug 2022 09:04:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661245464; bh=eO4wzGcORruDBbQHGEoSVy8v7g9gEkJj9bYk1j+gKKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GGOc/OJLUxdutP/2ddfZWPtY5x4tIiAk/7Tb6gWpgja0yQ3DitnrTxBai+qU/T0bV 6k4P7cFnhPaRRv7pAs1A2yV9QvBBq0zYO7HTY39OqeEmAlLBm9pY4pJeIRvnDj+dxD cZNL4Btvc1dT3qNHjzQJUyFUuzpde5gr/m+UvAm8= 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 4.19 087/287] libbpf: Fix the name of a reused map Date: Tue, 23 Aug 2022 10:24:16 +0200 Message-Id: <20220823080103.224063724@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080100.268827165@linuxfoundation.org> References: <20220823080100.268827165@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 249fa8d7376e..76cf63705c86 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1060,7 +1060,7 @@ static int bpf_map_find_btf_info(struct bpf_map *map,= const struct btf *btf) 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 @@ -1068,7 +1068,12 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) if (err) return 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 -errno; =20 --=20 2.35.1