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 B3CF9C433FE for ; Mon, 24 Jan 2022 21:08:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376581AbiAXVH5 (ORCPT ); Mon, 24 Jan 2022 16:07:57 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:53848 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1444634AbiAXVBO (ORCPT ); Mon, 24 Jan 2022 16:01:14 -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 A5DC061368; Mon, 24 Jan 2022 21:01:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4E10C340E5; Mon, 24 Jan 2022 21:01:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643058073; bh=WYGVexxiQzWsmwuFARY5sLnWD4LDm3nwZavgR065GQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ybugiiHT5Hbw073FMy7P+nlWmCucYzdSzD/sxbU+BPEbVl1y2feW2J6eOc4ZsIHJ5 vJKHw6mgXS37G46UW6K1D3tbKLmlD5nxNgTyW3R/E0aetga0HKdJ1A1B2XF04hv5dT yD+8toHP6A/+wQMu2HgwWqsDTTlay3TpRV2AzOho= 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 5.16 0173/1039] libbpf: Fix using invalidated memory in bpf_linker Date: Mon, 24 Jan 2022 19:32:42 +0100 Message-Id: <20220124184131.070872399@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: stable@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 94bdd97859285..6923a0ab3b127 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -2000,7 +2000,7 @@ 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++) { @@ -2033,6 +2033,9 @@ 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