From patchwork Sun Dec 19 23:45:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Wielaard X-Patchwork-Id: 49106 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 DDA12385840C for ; Sun, 19 Dec 2021 23:45:50 +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 396553858C60 for ; Sun, 19 Dec 2021 23:45:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 396553858C60 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 C700E302FBA8; Mon, 20 Dec 2021 00:45:40 +0100 (CET) Received: by reform (Postfix, from userid 1000) id 8F3D02E8374A; Mon, 20 Dec 2021 00:45:40 +0100 (CET) From: Mark Wielaard To: elfutils-devel@sourceware.org Subject: [PATCH] libdwfl: Handle unaligned Phdr in dwfl_segment_report_module Date: Mon, 20 Dec 2021 00:45:38 +0100 Message-Id: <20211219234538.1033805-1-mark@klomp.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Spam-Status: No, score=-10.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, 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 xlate functions only handle correctly aligned buffers. But they do handle src == dest. So if the source buffer isn't aligned correctly just copy it first into the destination (which is already correctly aligned). Signed-off-by: Mark Wielaard --- libdwfl/ChangeLog | 6 ++++++ libdwfl/dwfl_segment_report_module.c | 12 ++++++++++++ 2 files changed, 18 insertions(+) diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 6c7e0c4a..ac0fbe0f 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,9 @@ +2021-12-19 Mark Wielaard + + * dwfl_segment_report_module.c (dwfl_segment_report_module): Copy + ph_buffer and set xlatefrom.d_buf to phdrsp when ph_buffer is not + aligned. + 2021-12-19 Mark Wielaard * dwfl_segment_report_module.c (dwfl_segment_report_module): Copy diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c index 7f756392..de190e90 100644 --- a/libdwfl/dwfl_segment_report_module.c +++ b/libdwfl/dwfl_segment_report_module.c @@ -461,6 +461,18 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name, xlateto.d_buf = phdrsp; xlateto.d_size = phdrsp_bytes; + /* ph_ buffer may be unaligned, in which case xlatetom would not work. + xlatetom does work when the in and out d_buf are equal (but not + for any other overlap). */ + size_t phdr_align = (class32 + ? __alignof__ (Elf32_Phdr) + : __alignof__ (Elf64_Phdr)); + if (((uintptr_t) ph_buffer & (phdr_align - 1)) != 0) + { + memcpy (phdrsp, ph_buffer, phdrsp_bytes); + xlatefrom.d_buf = phdrsp; + } + /* Track the bounds of the file visible in memory. */ GElf_Off file_trimmed_end = 0; /* Proper p_vaddr + p_filesz end. */ GElf_Off file_end = 0; /* Rounded up to effective page size. */