From patchwork Thu Dec 23 22:19:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Wielaard X-Patchwork-Id: 49227 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 3BEEB3858407 for ; Thu, 23 Dec 2021 22:22:38 +0000 (GMT) X-Original-To: elfutils-devel@sourceware.org Delivered-To: elfutils-devel@sourceware.org Received: from gnu.wildebeest.org (gnu.wildebeest.org [45.83.234.184]) by sourceware.org (Postfix) with ESMTPS id EB4E53858406 for ; Thu, 23 Dec 2021 22:22:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org EB4E53858406 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=klomp.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=klomp.org Received: from reform (deer0x12.wildebeest.org [172.31.17.148]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id 26677302FBA8; Thu, 23 Dec 2021 23:22:03 +0100 (CET) Received: by reform (Postfix, from userid 1000) id B51002E8372E; Thu, 23 Dec 2021 23:22:02 +0100 (CET) From: Mark Wielaard To: elfutils-devel@sourceware.org Subject: [PATCH] libdwfl: Make sure dwfl_elf_phdr_memory_callback returns at least minread Date: Thu, 23 Dec 2021 23:19:31 +0100 Message-Id: <20211223221931.1183675-1-mark@klomp.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Spam-Status: No, score=-9.8 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , Cc: Mark Wielaard Errors-To: elfutils-devel-bounces+patchwork=sourceware.org@sourceware.org Sender: "Elfutils-devel" The callers of dwfl_elf_phdr_memory_callback assume at least minread bytes are read and available. Make sure to check start is smaller than elf->maximum_size before reading more. Return false if end - start is smaller than minread. Found by afl-fuzz. Signed-off-by: Mark Wielaard --- libdwfl/ChangeLog | 5 +++++ libdwfl/core-file.c | 6 +++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index abd5c34a..49a35e41 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,8 @@ +2021-12-23 Mark Wielaard + + * core-file.c (dwfl_elf_phdr_memory_callback): Check start < + elf->maximum_size and end - start < minread. + 2021-12-20 Mark Wielaard * dwfl_segment_report_module.c (dwfl_segment_report_module): Move diff --git a/libdwfl/core-file.c b/libdwfl/core-file.c index b04d1d18..d5be771f 100644 --- a/libdwfl/core-file.c +++ b/libdwfl/core-file.c @@ -1,5 +1,6 @@ /* Core file handling. Copyright (C) 2008-2010, 2013, 2015 Red Hat, Inc. + Copyright (C) 2011 Mark J. Wielaard This file is part of elfutils. This file is free software; you can redistribute it and/or modify @@ -320,7 +321,7 @@ dwfl_elf_phdr_memory_callback (Dwfl *dwfl, int ndx, (void) more (*buffer_available); /* If it's already on hand anyway, use as much as there is. */ - if (elf->map_address != NULL) + if (elf->map_address != NULL && start < elf->maximum_size) (void) more (elf->maximum_size - start); /* Make sure we don't look past the end of the actual file, @@ -332,6 +333,9 @@ dwfl_elf_phdr_memory_callback (Dwfl *dwfl, int ndx, if (unlikely (start >= end)) return false; + if (end - start < minread) + return false; + if (elf->map_address != NULL) { void *contents = elf->map_address + elf->start_offset + start;