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 7D74FC4167B for ; Mon, 24 Jan 2022 22:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1580808AbiAXWKr (ORCPT ); Mon, 24 Jan 2022 17:10:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1443036AbiAXVZK (ORCPT ); Mon, 24 Jan 2022 16:25:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5D86C0A1CF3; Mon, 24 Jan 2022 12:18:02 -0800 (PST) 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 52AC6614CB; Mon, 24 Jan 2022 20:18:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D491C340E5; Mon, 24 Jan 2022 20:18:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643055481; bh=sWrk5jbRVJlqAG402l2iX4Ufc9ZFk7kkEs6gF9yU8fc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pUFu8ZIFli7sXl5+7GB3OMCJ9obIqmgYG76BAjhNtmhKZDPqDj8rR5rvaYda2HmDK pBWXRiAs8ydFb6NY9bWH7JDs2IO8dgg8CmYNmn7Jq0HhjB1mrsSgbiTa0tcCIimuMH UM4OVlPJ7P/ehj3fAjxx9f8q7zTaX+u+QvMKC3+U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrii Nakryiko , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.15 148/846] libbpf: Fix using invalidated memory in bpf_linker Date: Mon, 24 Jan 2022 19:34:25 +0100 Message-Id: <20220124184106.090671883@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@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 593835377f24ca1bb98008ec1dc3baefe491ad6e ] add_dst_sec() can invalidate bpf_linker's section index making dst_symtab pointer pointing into unallocated memory. Reinitialize dst_symtab pointer on each iteration to make sure it's always valid. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211124002325.1737739-7-andrii@kernel.org Signed-off-by: Sasha Levin --- tools/lib/bpf/linker.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 84095a2c2ef2a..6b2f59ddb6918 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -2001,7 +2001,7 @@ add_sym: static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj) { struct src_sec *src_symtab = &obj->secs[obj->symtab_sec_idx]; - struct dst_sec *dst_symtab = &linker->secs[linker->symtab_sec_idx]; + struct dst_sec *dst_symtab; int i, err; for (i = 1; i < obj->sec_cnt; i++) { @@ -2034,6 +2034,9 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob return -1; } + /* add_dst_sec() above could have invalidated linker->secs */ + dst_symtab = &linker->secs[linker->symtab_sec_idx]; + /* shdr->sh_link points to SYMTAB */ dst_sec->shdr->sh_link = linker->symtab_sec_idx; -- 2.34.1