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 A2E8CC4332F for ; Tue, 25 Jan 2022 02:47:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379980AbiAYCrO (ORCPT ); Mon, 24 Jan 2022 21:47:14 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:53752 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1444546AbiAXVBI (ORCPT ); Mon, 24 Jan 2022 16:01:08 -0500 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 dfw.source.kernel.org (Postfix) with ESMTPS id 9C7FB60C60; Mon, 24 Jan 2022 21:01:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5008C340E5; Mon, 24 Jan 2022 21:01:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643058067; bh=a96iE1mVlz1u2n3mjpHmP704KBiCwyNGseo3af3XAnI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OhE82H9lwcLpTMTdT/hg1QvYjRKHQmFB0T0N5c1LoJpqvpDg8C4XSTo0PJVeULRv7 PzGhov2IHWLN84SX1l9FYDYSWntlal3wz62HbGjLMbjED4QFhuNLwjjnAAMx/EqHjx wfyQwC4anNa6h56m4zyR06+PIQjcDILjdKaMih+8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Evgeny Vereshchagin , Andrii Nakryiko , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.16 0171/1039] libbpf: Fix potential misaligned memory access in btf_ext__new() Date: Mon, 24 Jan 2022 19:32:40 +0100 Message-Id: <20220124184130.990042419@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184125.121143506@linuxfoundation.org> References: <20220124184125.121143506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrii Nakryiko [ Upstream commit 401891a9debaf0a684502f2aaecf53448cee9414 ] Perform a memory copy before we do the sanity checks of btf_ext_hdr. This prevents misaligned memory access if raw btf_ext data is not 4-byte aligned ([0]). While at it, also add missing const qualifier. [0] Closes: https://github.com/libbpf/libbpf/issues/391 Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") Reported-by: Evgeny Vereshchagin Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211124002325.1737739-3-andrii@kernel.org Signed-off-by: Sasha Levin --- tools/lib/bpf/btf.c | 10 +++++----- tools/lib/bpf/btf.h | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7e4c5586bd877..c2400804d6bac 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -2711,15 +2711,11 @@ void btf_ext__free(struct btf_ext *btf_ext) free(btf_ext); } -struct btf_ext *btf_ext__new(__u8 *data, __u32 size) +struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) { struct btf_ext *btf_ext; int err; - err = btf_ext_parse_hdr(data, size); - if (err) - return libbpf_err_ptr(err); - btf_ext = calloc(1, sizeof(struct btf_ext)); if (!btf_ext) return libbpf_err_ptr(-ENOMEM); @@ -2732,6 +2728,10 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) } memcpy(btf_ext->data, data, size); + err = btf_ext_parse_hdr(btf_ext->data, size); + if (err) + goto done; + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { err = -EINVAL; goto done; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index bc005ba3ceec3..17c0a46d8cd22 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -157,7 +157,7 @@ LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, __u32 expected_value_size, __u32 *key_type_id, __u32 *value_type_id); -LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); +LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size); LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size); -- 2.34.1