From patchwork Wed Dec 16 13:26:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vivek Dasmohapatra X-Patchwork-Id: 41446 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 958A8383F879; Wed, 16 Dec 2020 13:27:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 958A8383F879 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1608125272; bh=uLXu/Ed8GnN9IzoC6VN4t4jYqIWzeF0p+x4LFqy2t/8=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=uSuB6Z9z9IHDSdv6PPlxu+ua7YuwVLWxFL4Zdom/i7esKiV37J5GxbkMH6T9XDMT1 gpceqhHMckxaYVhiRAl5BhuJiUo+Hyh4+eYBhxhTl+rkRkKYC2GgQ9Zeir6ewA14b9 puGEhLiJKGQU2mLHZ3gE81pdSCib+WkdjJ1czM20= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by sourceware.org (Postfix) with ESMTPS id 5AA9E3840C1F for ; Wed, 16 Dec 2020 13:27:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 5AA9E3840C1F Received: from noise.cbg.collabora.co.uk (unknown [IPv6:2001:4d48:ad5c:ef00:8e70:5aff:fe59:c29c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vivek) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 84E851F45651 for ; Wed, 16 Dec 2020 13:27:40 +0000 (GMT) To: libc-alpha Subject: [RFC][PATCH v7 00/20] Implementation of RTLD_SHARED for dlmopen Date: Wed, 16 Dec 2020 13:26:30 +0000 Message-Id: <20201216132650.22949-1-vivek@collabora.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00, KAM_ASCII_DIVIDERS, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: =?utf-8?q?Vivek_Das=C2=A0Mohapatra_via_Libc-alpha?= From: Vivek Dasmohapatra Reply-To: =?utf-8?q?Vivek_Das=C2=A0Mohapatra?= Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This is a revision of a previous patchset that I posted here regarding https://sourceware.org/bugzilla/show_bug.cgi?id=22745 Introduction: ======================================================================= As discussed in the URL above dlmopen requires a mechanism for [optionally] sharing some objects between more than one namespace. The following patchset provides an implementation for this: If an object is loaded with the new RTLD_SHARED flag we instead ensure that a "master" copy exists (and is flagged as no-delete) in the main namespace and a thin wrapper or clone is placed in the target namespace. This patch series should address all the comments received on the earlier (v1) series, and fixes a bug in the previous (v2) series which left the r_debug struct in an inconsistent state when creating a proxy triggered the initial load of a DSO into the main namespace. ======================================================================= In addition this patch series implements the following: - dlmopen will implicitly apply RTLD_SHARED to the libc/libpthread group (requires a patched binutils/ld so that the libc family DSOs can be flagged as requiring this behaviour) - binutils patchset accepted upstream; - https://sourceware.org/git/?p=binutils-gdb.git - commit 8a87b2791181eb7fc1533ffaeb95df8d87d41493 - LD_AUDIT paths will NOT apply this implict sharing rule: audit libraries will continue to be completely isolated. - The mechanism for tagging DSOs as implicitly shared has been changed from a DT_FLAGS_1 flag to a DT_VALRNGHI/LO range dynamic section tag. (Based on feedback on the binutils side of this patch series). - DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE - A flag RTLD_ISOLATE which is used inernally to suppress RTLD_SHARED behaviour when audit libraries are being loaded, and is also made available to users who really want a completely separate copy of glibc in their new namespace. - Tests for the new dlmopen behaviour - Adds the unique dso flag to htl/libpthread.so as well as nptl I have not yet implemented, but plan to address once this series is accepted/acceptable: - Sensible RTLD_GLOBAL semantics for dlmopened DSOs in non-base namespaces - dl_iterate_ns_phdr (cf dl_iterate_phdr but taking a namespace argument) Vivek Das Mohapatra (20): Declare and describe the dlmopen RTLD_SHARED flag include/link.h: Update the link_map struct to allow proxies elf/dl-object.c: Implement a helper function to proxy link_map entries elf/dl-load.c, elf-dl-open.c: Implement RTLD_SHARED dlmopen proxying elf/dl-fini.c: Handle proxy link_map entries in the shutdown path elf/dl-init.c: Skip proxied link map entries in the dl init path elf/dl-open.c: Don't try libc linit in namespaces with no libc mapping elf/dl-open.c: when creating a proxy check the libc_map in NS 0 Define a new dynamic section tag - DT_GNU_FLAGS_1 Abstract the loaded-DSO search code into a private helper function Compare loaded DSOs by file ID and check for DF_GNU_1_UNIQUE Use the new DSO finder helper function since we have it Use the DSO search helper to check for preloaded DT_GNU_UNIQUE DSOs When loading DSOs into alternate namespaces check for DT_GNU_UNIQUE Suppress audit calls when a (new) namespace is empty Suppress inter-namespace DSO sharing for audit libraries dlsym, dlvsym should be able to look up symbols via DSO proxies Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE dynamic section+flag to glibc DSOs Add dlmopen / RTLD_SHARED tests Restore separate libc loading for the TLS/namespace storage test Makeconfig | 1 + Makerules | 2 +- bits/dlfcn.h | 10 + elf/Makefile | 97 ++- elf/dl-close.c | 43 +- elf/dl-fini.c | 6 +- elf/dl-init.c | 4 +- elf/dl-load.c | 227 +++++- elf/dl-object.c | 84 +++ elf/dl-open.c | 108 ++- elf/dl-sym.c | 14 + elf/elf.h | 7 +- elf/get-dynamic-info.h | 12 + elf/rtld.c | 2 +- elf/tst-dlmopen-auditmod.c | 23 + elf/tst-dlmopen-common.h | 33 + elf/tst-dlmopen-main.h | 1022 ++++++++++++++++++++++++++ elf/tst-dlmopen-modules.h | 20 + elf/tst-dlmopen-rtld-audit-shared1.c | 11 + elf/tst-dlmopen-rtld-audit-shared2.c | 11 + elf/tst-dlmopen-rtld-audit-shared3.c | 11 + elf/tst-dlmopen-rtld-audit-shared4.c | 11 + elf/tst-dlmopen-rtld-audit-shared5.c | 11 + elf/tst-dlmopen-rtld-audit-shared6.c | 11 + elf/tst-dlmopen-rtld-audit-unique1.c | 11 + elf/tst-dlmopen-rtld-audit-unique2.c | 11 + elf/tst-dlmopen-rtld-audit-unique3.c | 11 + elf/tst-dlmopen-rtld-audit-unique4.c | 11 + elf/tst-dlmopen-rtld-audit-unique5.c | 11 + elf/tst-dlmopen-rtld-audit-unique6.c | 11 + elf/tst-dlmopen-rtld-shared1.c | 11 + elf/tst-dlmopen-rtld-shared1.h | 65 ++ elf/tst-dlmopen-rtld-shared2.c | 11 + elf/tst-dlmopen-rtld-shared2.h | 67 ++ elf/tst-dlmopen-rtld-shared3.c | 11 + elf/tst-dlmopen-rtld-shared3.h | 44 ++ elf/tst-dlmopen-rtld-shared4.c | 11 + elf/tst-dlmopen-rtld-shared4.h | 15 + elf/tst-dlmopen-rtld-shared5.c | 11 + elf/tst-dlmopen-rtld-shared5.h | 26 + elf/tst-dlmopen-rtld-shared6.c | 11 + elf/tst-dlmopen-rtld-shared6.h | 37 + elf/tst-dlmopen-rtld-unique1.c | 11 + elf/tst-dlmopen-rtld-unique1.h | 87 +++ elf/tst-dlmopen-rtld-unique2.c | 11 + elf/tst-dlmopen-rtld-unique2.h | 26 + elf/tst-dlmopen-rtld-unique3.c | 11 + elf/tst-dlmopen-rtld-unique3.h | 14 + elf/tst-dlmopen-rtld-unique4.c | 11 + elf/tst-dlmopen-rtld-unique4.h | 15 + elf/tst-dlmopen-rtld-unique5.c | 11 + elf/tst-dlmopen-rtld-unique5.h | 59 ++ elf/tst-dlmopen-rtld-unique6.c | 11 + elf/tst-dlmopen-rtld-unique6.h | 52 ++ elf/tst-dlmopen-sharedmod-norm.c | 11 + elf/tst-dlmopen-sharedmod-uniq.c | 11 + elf/tst-dlmopen-std-do-test.h | 11 + elf/tst-tls-ie-dlmopen.c | 4 +- htl/Makefile | 2 +- iconvdata/Makefile | 1 + include/elf.h | 2 + include/link.h | 7 +- nptl/Makefile | 2 +- sysdeps/generic/ldsodefs.h | 9 + sysdeps/mips/bits/dlfcn.h | 10 + 65 files changed, 2493 insertions(+), 63 deletions(-) create mode 100644 elf/tst-dlmopen-auditmod.c create mode 100644 elf/tst-dlmopen-common.h create mode 100644 elf/tst-dlmopen-main.h create mode 100644 elf/tst-dlmopen-modules.h create mode 100644 elf/tst-dlmopen-rtld-audit-shared1.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared2.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared3.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared4.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared5.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared6.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique1.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique2.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique3.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique4.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique5.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique6.c create mode 100644 elf/tst-dlmopen-rtld-shared1.c create mode 100644 elf/tst-dlmopen-rtld-shared1.h create mode 100644 elf/tst-dlmopen-rtld-shared2.c create mode 100644 elf/tst-dlmopen-rtld-shared2.h create mode 100644 elf/tst-dlmopen-rtld-shared3.c create mode 100644 elf/tst-dlmopen-rtld-shared3.h create mode 100644 elf/tst-dlmopen-rtld-shared4.c create mode 100644 elf/tst-dlmopen-rtld-shared4.h create mode 100644 elf/tst-dlmopen-rtld-shared5.c create mode 100644 elf/tst-dlmopen-rtld-shared5.h create mode 100644 elf/tst-dlmopen-rtld-shared6.c create mode 100644 elf/tst-dlmopen-rtld-shared6.h create mode 100644 elf/tst-dlmopen-rtld-unique1.c create mode 100644 elf/tst-dlmopen-rtld-unique1.h create mode 100644 elf/tst-dlmopen-rtld-unique2.c create mode 100644 elf/tst-dlmopen-rtld-unique2.h create mode 100644 elf/tst-dlmopen-rtld-unique3.c create mode 100644 elf/tst-dlmopen-rtld-unique3.h create mode 100644 elf/tst-dlmopen-rtld-unique4.c create mode 100644 elf/tst-dlmopen-rtld-unique4.h create mode 100644 elf/tst-dlmopen-rtld-unique5.c create mode 100644 elf/tst-dlmopen-rtld-unique5.h create mode 100644 elf/tst-dlmopen-rtld-unique6.c create mode 100644 elf/tst-dlmopen-rtld-unique6.h create mode 100644 elf/tst-dlmopen-sharedmod-norm.c create mode 100644 elf/tst-dlmopen-sharedmod-uniq.c create mode 100644 elf/tst-dlmopen-std-do-test.h