From patchwork Fri Dec 1 18:24:36 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 24679 Received: (qmail 130695 invoked by alias); 1 Dec 2017 18:24:47 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 130675 invoked by uid 89); 1 Dec 2017 18:24:47 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-25.2 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, KB_WAM_FROM_NAME_SINGLEWORD, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-oi0-f54.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=YPhcGDMKO074FUIzDqLc7Icqo2+hHW3TUnX+vIwVe60=; b=b79XXQQbt4UdKaISEIMlKuN+239GBGz9kZ1YO7mOx7ld1kja9w6XBsq2K687NOdrGR 175XBWEI/zNgqCAb7t3hFcVyyr2NE8gnw+a65NYp2tFAnKrBI/BenLdWyx/itLWkKCzc +f0Yk778rlqMretNF5yrblzIF1BPx0LuwgWHZIp6bToYMaC8Rd5SuVNeLzkn/8qKGxCM 6wU/80aanjz0lB8bv29Sa0cm+x8K+am5HGrWFGyjA4NyhPXkX1JfozVeTbPrWXtZn5Zu LJowx/7Ltnfo8TrOGQ9b1MZgy7bFggSG+ahZYrWFKwInF0wlua+0Pczf/TKwx74JQQ0N 20DA== X-Gm-Message-State: AJaThX6s6md/tO1GC4ZUBSx5hJis6mWAjnxjRZNoa3BuZWGl156ckx71 eWs3HaQm6E+sX0y/P17vKsgaxQ7k5LBFYepaoYk= X-Google-Smtp-Source: AGs4zMZ4tf7ZnETOeU5xiPUTLGK/N0LfbmNwNeH62Kwn2KPCvM9/GqOBcmYc/pmuL8h2HXH5zhiiTZXt0U2vcRzUPk0= X-Received: by 10.202.187.212 with SMTP id l203mr8152136oif.316.1512152677280; Fri, 01 Dec 2017 10:24:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <02278c7c-ade4-c8f2-c978-e66f77a101bd@redhat.com> References: <5A12C781.3030700@arm.com> <5A18196C.90208@arm.com> <02278c7c-ade4-c8f2-c978-e66f77a101bd@redhat.com> From: "H.J. Lu" Date: Fri, 1 Dec 2017 10:24:36 -0800 Message-ID: Subject: Re: PING^N: [PATCH] Add --enable-static-pie to build static PIE [BZ #19574] To: "Carlos O'Donell" Cc: Szabolcs Nagy , nd , Joseph Myers , GNU C Library On Thu, Nov 30, 2017 at 1:44 PM, Carlos O'Donell wrote: > H.J., > > High Level: > > At a high level I have no objection with the idea of static PIE executables, > it makes sense to support such things. Thanks for your feedbacks. > My only nit is that we need to do a better job of explaining to users why > they would use them and under what circumstances. To that end you have a bit > more work to do in the commit message, install.texit, and NEWS entry. > > Design: > > I have one design question below which around testing static non-PIE executables > in a --enable-static-pie build. See below. > > Implementation: > > Everything looks good except the use of firstword in +link-static-before-libc, > which I describe below. I think this is a hack and should be changed to better > represent the expected semantics and structure you are looking to support. Fixed. > Thank you for your work in this area. > > Look forward to a v2. > >> From 7026a79c1f71f5decd135208503fd4186193ffb8 Mon Sep 17 00:00:00 2001 >> From: "H.J. Lu" >> Date: Mon, 17 Jul 2017 08:17:32 -0700 >> Subject: [PATCH] Add --enable-static-pie configure option to build static PIE >> [BZ #19574] >> >> Dynamic linker, ld.so, is a standalone program which can be loaded at >> any address. This patch adds a configure option, --enable-static-pie, >> to embed the part of ld.so in static executable to create static position >> independent executable (static PIE). A static PIE is similar to static >> executable, but can be loaded at any address without help from a dynamic >> linker. When --enable-static-pie is used to configure glibc, libc.a is >> built as PIE and all static executables, including tests, are built as >> static PIE. The resulting libc.a can be used together with GCC 8 or >> above to build static PIE with the compiler option, -static-pie. But >> GCC 8 isn't required to build glibc with --enable-static-pie. When an >> older GCC is used to build glibc with --enable-static-pie, proper input >> files are passed to linker to create static executables as static PIE, >> together with "-z text" to prevent dynamic relocations in read-only >> segments, which are allowed in static PIE. > > You write "which are allowed", shouldn't that be "which are not allowed"? Fixed. > The commit message must explain the following: > > * Why would a user use this feature? > - What does it provide over and beyond existing static executables > > * How does a user decide to use this feature? > - Should everyone use it? > - Should you use it if you care about security, and what does it cost? > > Please include the answers to these questions in a the next versions > commit message. I added : Static PIE extends address space layout randomization to static executables. It provides additional security hardening benefits at the cost of some memory and performance. Is this OK? >> @@ -420,7 +440,7 @@ endif >> # Command for statically linking programs with the C library. >> ifndef +link-static >> +link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \ >> - $(DEFAULT-LDFLAGS-$(@F)) \ >> + $(firstword $(DEFAULT-LDFLAGS-$(@F)) $(default-pie-ldflag)) \ > > Is the use of firstword here just a hack to put $(no-pie-ldflag) first so > you can override it with the subsequent $(default-pie-ldflag)? > > It is not a robust design to use firstword here because it implies that the > DEFAUTL-LDFLAGS-$(@F) has some structure that we are not documenting. > > I would like to see this done some other way. My preference would be for a new > value other than DEFAULT-LDFLAGS to control the PIE-ness of the built progarm. > I replaced DEFAUTL-LDFLAGS-$(@F) with $($(@F)-no-pie). Now I have # Command for statically linking programs with the C library. ifndef +link-static +link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \ - $(DEFAULT-LDFLAGS-$(@F)) \ + $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)) \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ >> >> diff --git a/NEWS b/NEWS >> index ab14d1eb1b..61598be94d 100644 >> --- a/NEWS >> +++ b/NEWS >> @@ -9,6 +9,11 @@ Version 2.27 >> >> Major new features: >> >> +* Add --enable-static-pie configure option to build static PIE. The >> + resulting libc.a can be used with the GCC option, -static-pie, which >> + is available with GCC 8 or above, to create static position independent >> + executable (static PIE). >> + > > The description of a new configure option is relevant only to INSTALL. > > We must explain when users would use this feature and why. NEWS entries are > user facing and must explain the function of the new feature. Does it improve > security for static binaries? Should users switch to using them instead of > normal static binaries? > > Lastly, we must explain which machines are supported in this initial release > of the feature. Only x86_64? You need not check all machines, other maintainers > can check and adjust the NEWS entry, but we have to commit to at least one > machine supporting this feature, which I assume is x86_64. > > For example: > > * The GNU C Library can now be compiled with support for building static > PIE executables (See --enable-static-pie in INSTALL). These static PIE > exectuables are like static executables but can be loaded at any address > and provide additional security hardening benefits at the cost of some > memory and performance. When the library is built with --enable-static-pie > the resulting libc.a is usable with GCC 8 and above to create static PIE > executables using the GCC option '-static-pie'. This feature is currently > supported on x86_64. > I took your example. Thanks. > >> diff --git a/configure.ac b/configure.ac >> index 8ebc490a55..ae219f8fe0 100644 >> --- a/configure.ac >> +++ b/configure.ac >> @@ -176,6 +176,11 @@ AC_ARG_ENABLE([profile], >> [build profiled library @<:@default=no@:>@]), >> [profile=$enableval], >> [profile=no]) >> +AC_ARG_ENABLE([static-pie], >> + AC_HELP_STRING([--enable-static-pie], >> + [build static executables as PIE @<:@default=no@:>@]), > > This does 2 things: > * It enables support for building static PIE executables. > * It builds all static binaries and tests in the testsuite as static PIE executables. > > It should say that e.g. > > "Enable static PIE executable support and use it in the testsuite." > > I understand the desire to use such a functionality to test static PIE executables > by converting the entire testsuite to use them, but we still need to test non-PIE > static executables? How are we still doing that after this change? > > How are we testing non-PIE static executables after this change? This is similar to PIE vs non-PIE. When you build glibc with GCC defaulting to PIE, most of dynamic tests are built as PIE, except for a couple of them linked with $(no-pie-ldflag). I added elf/tst-tls1-static-non-pie.c which is always built as non-PIE static executable, regardless if --enable-static-pie is used to configure glibc. To get better coverage for non-PIE, we need to build glibc with GCC defaulting to non-PIE and configure glibc without --enable-static-pie. >> diff --git a/manual/install.texi b/manual/install.texi >> index f1fa28c937..86193ade3f 100644 >> --- a/manual/install.texi >> +++ b/manual/install.texi >> @@ -120,6 +120,13 @@ Don't build shared libraries even if it is possible. Not all systems >> support shared libraries; you need ELF support and (currently) the GNU >> linker. >> >> +@item --enable-static-pie > > This should be rewritten to explain the feature that it enables first, > and then the ancilliary benefits like turning it on in the testsuite. > >> +Build static executables, including tests, as position independent >> +executable (static PIE) which is similar to static executable, but can >> +be loaded at any address without help from a dynamic linker. The >> +resulting libc.a can be used with the GCC option, -static-pie, which >> +is available with GCC 8 or above, to create static PIE. >> + I changed it to '--enable-static-pie' Enable static position independent executable (static PIE) support. Static PIE is similar to static executable, but can be loaded at any address without help from a dynamic linker. All static programs as well as static tests are built as static PIE, except for those marked with no-pie. The resulting glibc can be used with the GCC option, -static-pie, which is available with GCC 8 or above, to create static PIE. Here is the updated patch. Using GCC 7 and binutils master branch, build-many-glibcs.py with --enable-static-pie with all patches for static PIE applied have the following build successes: PASS: glibcs-aarch64_be-linux-gnu build PASS: glibcs-aarch64-linux-gnu build PASS: glibcs-armeb-linux-gnueabi-be8 build PASS: glibcs-armeb-linux-gnueabi build PASS: glibcs-armeb-linux-gnueabihf-be8 build PASS: glibcs-armeb-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabi build PASS: glibcs-arm-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabihf-v7a build PASS: glibcs-arm-linux-gnueabihf-v7a-disable-multi-arch build PASS: glibcs-m68k-linux-gnu build PASS: glibcs-microblazeel-linux-gnu build PASS: glibcs-microblaze-linux-gnu build PASS: glibcs-mips64el-linux-gnu-n32 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n32-soft build PASS: glibcs-mips64el-linux-gnu-n64 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n64-soft build PASS: glibcs-mips64-linux-gnu-n32 build PASS: glibcs-mips64-linux-gnu-n32-nan2008 build PASS: glibcs-mips64-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n32-soft build PASS: glibcs-mips64-linux-gnu-n64 build PASS: glibcs-mips64-linux-gnu-n64-nan2008 build PASS: glibcs-mips64-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n64-soft build PASS: glibcs-mipsel-linux-gnu build PASS: glibcs-mipsel-linux-gnu-nan2008 build PASS: glibcs-mipsel-linux-gnu-nan2008-soft build PASS: glibcs-mipsel-linux-gnu-soft build PASS: glibcs-mips-linux-gnu build PASS: glibcs-mips-linux-gnu-nan2008 build PASS: glibcs-mips-linux-gnu-nan2008-soft build PASS: glibcs-mips-linux-gnu-soft build PASS: glibcs-nios2-linux-gnu build PASS: glibcs-powerpc64le-linux-gnu build PASS: glibcs-powerpc64-linux-gnu build PASS: glibcs-tilegxbe-linux-gnu-32 build PASS: glibcs-tilegxbe-linux-gnu build PASS: glibcs-tilegx-linux-gnu-32 build PASS: glibcs-tilegx-linux-gnu build PASS: glibcs-tilepro-linux-gnu build I don't know how many of them actually work, except for aarch64. Thanks. From 86d8013ccc24e4c07fdc6da04dac0448c4f5fc29 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 17 Jul 2017 08:17:32 -0700 Subject: [PATCH] Add --enable-static-pie configure option to build static PIE [BZ #19574] Dynamic linker, ld.so, is a standalone program which can be loaded at any address. This patch adds a configure option, --enable-static-pie, to embed the part of ld.so in static executable to create static position independent executable (static PIE). A static PIE is similar to static executable, but can be loaded at any address without help from a dynamic linker. When --enable-static-pie is used to configure glibc, libc.a is built as PIE and all static executables, including tests, are built as static PIE. The resulting libc.a can be used together with GCC 8 or above to build static PIE with the compiler option, -static-pie. But GCC 8 isn't required to build glibc with --enable-static-pie. Only GCC with PIE support is needed. When an older GCC is used to build glibc with --enable-static-pie, proper input files are passed to linker to create static executables as static PIE, together with "-z text" to prevent dynamic relocations in read-only segments, which are not allowed in static PIE. Static PIE extends address space layout randomization to static executables. It provides additional security hardening benefits at the cost of some memory and performance. The following changes are made for static PIE: 1. Add a new function, _dl_relocate_static_pie, to: a. Get the run-time load address. b. Read the dynamic section. c. Perform dynamic relocations. Dynamic linker also performs these steps. But static PIE doesn't load any shared objects. 2. Call _dl_relocate_static_pie at entrance of LIBC_START_MAIN in libc.a. crt1.o, which is used to create dynamic and non-PIE static executables, is updated to include a dummy _dl_relocate_static_pie. rcrt1.o is added to create static PIE, which will link in the real _dl_relocate_static_pie. grcrt1.o is also added to create static PIE with -pg. GCC 8 has been updated to support rcrt1.o and grcrt1.o for static PIE. Static PIE can work on all architectures which support PIE, provided: 1. Target must support accessing of local functions without dynamic relocations, which is needed in start.S to call __libc_start_main with function addresses of __libc_csu_init, __libc_csu_fini and main. All functions in static PIE are local functions. If PIE start.S can't reach main () defined in a shared object, the code sequence: pass addess of local_main to __libc_start_main ... local_main: tail call to main via PLT can be used. 2. start.S is updated to check PIC instead SHARED for PIC code path and avoid dynamic relocation, when PIC is defined and SHARED isn't defined, to support static PIE. Patches are submitted for aarch64, hppa, m68k, microblaze and sparc. 3. All assembly codes are updated check PIC instead SHARED for PIC code path to avoid dynamic relocations in read-only sections. 4. All assembly codes are updated check SHARED instead PIC for static symbol name. A patch is submitted for tile. 5. elf_machine_load_address in dl-machine.h are updated to support static PIE. Patches are submitted for aarch64, s390 and sh. 6. __brk works without TLS nor dynamic relocations in read-only section so that it can be used by __libc_setup_tls to initializes TLS in static PIE. NB: When glibc is built with GCC defaulted to PIE, libc.a is compiled with -fPIE, regardless if --enable-static-pie is used to configure glibc. When glibc is configured with --enable-static-pie, libc.a is compiled with -fPIE, regardless wether GCC defaults to PIE or not. The same libc.a can be used to build both static executable and static PIE. There is no need for separate PIE copy of libc.a. On x86-64, the normal static sln: text data bss dec hex filename 625425 8284 5456 639165 9c0bd elf/sln the static PIE sln: text data bss dec hex filename 657626 20636 5392 683654 a6e86 elf/sln The code size is increased by 5% and the binary size is increased by 7%. Linker requirements to build glibc with --enable-static-pie: 1. Linker supports --no-dynamic-linker to remove PT_INTERP segment from static PIE. 2. Linker can create working static PIE. The x86-64 linker needs the fix for https://sourceware.org/bugzilla/show_bug.cgi?id=21782 The i386 linker needs to be able to convert "movl main@GOT(%ebx), %eax" to "leal main@GOTOFF(%ebx), %eax" if main is defined locally. Binutils 2.29 or above are OK for i686 and x86-64. But linker status for other targets need to be verified. 3. Linker should resolve undefined weak symbols to 0 in static PIE: https://sourceware.org/bugzilla/show_bug.cgi?id=22269 4. Many ELF backend linkers incorrectly check bfd_link_pic for TLS relocations, which should check bfd_link_executable instead: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 Tested on aarch64, i686 and x86-64. Using GCC 7 and binutils master branch, build-many-glibcs.py with --enable-static-pie with all patches for static PIE applied have the following build successes: PASS: glibcs-aarch64_be-linux-gnu build PASS: glibcs-aarch64-linux-gnu build PASS: glibcs-armeb-linux-gnueabi-be8 build PASS: glibcs-armeb-linux-gnueabi build PASS: glibcs-armeb-linux-gnueabihf-be8 build PASS: glibcs-armeb-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabi build PASS: glibcs-arm-linux-gnueabihf build PASS: glibcs-arm-linux-gnueabihf-v7a build PASS: glibcs-arm-linux-gnueabihf-v7a-disable-multi-arch build PASS: glibcs-m68k-linux-gnu build PASS: glibcs-microblazeel-linux-gnu build PASS: glibcs-microblaze-linux-gnu build PASS: glibcs-mips64el-linux-gnu-n32 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008 build PASS: glibcs-mips64el-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n32-soft build PASS: glibcs-mips64el-linux-gnu-n64 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008 build PASS: glibcs-mips64el-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64el-linux-gnu-n64-soft build PASS: glibcs-mips64-linux-gnu-n32 build PASS: glibcs-mips64-linux-gnu-n32-nan2008 build PASS: glibcs-mips64-linux-gnu-n32-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n32-soft build PASS: glibcs-mips64-linux-gnu-n64 build PASS: glibcs-mips64-linux-gnu-n64-nan2008 build PASS: glibcs-mips64-linux-gnu-n64-nan2008-soft build PASS: glibcs-mips64-linux-gnu-n64-soft build PASS: glibcs-mipsel-linux-gnu build PASS: glibcs-mipsel-linux-gnu-nan2008 build PASS: glibcs-mipsel-linux-gnu-nan2008-soft build PASS: glibcs-mipsel-linux-gnu-soft build PASS: glibcs-mips-linux-gnu build PASS: glibcs-mips-linux-gnu-nan2008 build PASS: glibcs-mips-linux-gnu-nan2008-soft build PASS: glibcs-mips-linux-gnu-soft build PASS: glibcs-nios2-linux-gnu build PASS: glibcs-powerpc64le-linux-gnu build PASS: glibcs-powerpc64-linux-gnu build PASS: glibcs-tilegxbe-linux-gnu-32 build PASS: glibcs-tilegxbe-linux-gnu build PASS: glibcs-tilegx-linux-gnu-32 build PASS: glibcs-tilegx-linux-gnu build PASS: glibcs-tilepro-linux-gnu build and the following build failures: FAIL: glibcs-alpha-linux-gnu build elf/sln is failed to link due to: assertion fail bfd/elf64-alpha.c:4125 This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-hppa-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault] https://sourceware.org/bugzilla/show_bug.cgi?id=22537 FAIL: glibcs-ia64-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault] FAIL: glibcs-powerpc-linux-gnu build FAIL: glibcs-powerpc-linux-gnu-soft build FAIL: glibcs-powerpc-linux-gnuspe build FAIL: glibcs-powerpc-linux-gnuspe-e500v1 build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22264 FAIL: glibcs-powerpc-linux-gnu-power4 build elf/sln is failed to link due to: findlocale.c:96:(.text+0x22c): @local call to ifunc memchr This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-s390-linux-gnu build elf/sln is failed to link due to: collect2: fatal error: ld terminated with signal 11 [Segmentation fault], core dumped assertion fail bfd/elflink.c:14299 This is caused by linker bug and/or non-PIC code in PIE libc.a. FAIL: glibcs-sh3eb-linux-gnu build FAIL: glibcs-sh3-linux-gnu build FAIL: glibcs-sh4eb-linux-gnu build FAIL: glibcs-sh4eb-linux-gnu-soft build FAIL: glibcs-sh4-linux-gnu build FAIL: glibcs-sh4-linux-gnu-soft build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 Also TLS code sequence in SH assembly syscalls in glibc doesn't match TLS code sequence expected by ld: https://sourceware.org/bugzilla/show_bug.cgi?id=22270 FAIL: glibcs-sparc64-linux-gnu build FAIL: glibcs-sparcv9-linux-gnu build FAIL: glibcs-tilegxbe-linux-gnu build FAIL: glibcs-tilegxbe-linux-gnu-32 build FAIL: glibcs-tilegx-linux-gnu build FAIL: glibcs-tilegx-linux-gnu-32 build FAIL: glibcs-tilepro-linux-gnu build elf/sln is failed to link due to: ld: read-only segment has dynamic relocations. This is caused by linker bug and/or non-PIC code in PIE libc.a. See: https://sourceware.org/bugzilla/show_bug.cgi?id=22263 [BZ #19574] * INSTALL: Regenerated. * Makeconfig (real-static-start-installed-name): New. (pic-default): Updated for --enable-static-pie. (pie-default): New for --enable-static-pie. (default-pie-ldflag): Likewise. (+link-static-before-libc): Replace $(DEFAULT-LDFLAGS-$(@F)) with $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)). Replace $(static-start-installed-name) with $(real-static-start-installed-name). (+prectorT): Updated for --enable-static-pie. (+postctorT): Likewise. (CFLAGS-.o): Add $(pie-default). (CFLAGS-.op): Likewise. * NEWS: Mention --enable-static-pie. * config.h.in (ENABLE_STATIC_PIE): New. * configure.ac (--enable-static-pie): New configure option. (have-no-dynamic-linker): New LIBC_CONFIG_VAR. (have-static-pie): Likewise. Enable static PIE if linker supports --no-dynamic-linker. (ENABLE_STATIC_PIE): New AC_DEFINE. (enable-static-pie): New LIBC_CONFIG_VAR. * configure: Regenerated. * csu/Makefile (omit-deps): Add r$(start-installed-name) and gr$(start-installed-name) for --enable-static-pie. (extra-objs): Likewise. (install-lib): Likewise. (extra-objs): Add static-reloc.o and static-reloc.os ($(objpfx)$(start-installed-name)): Also depend on $(objpfx)static-reloc.o. ($(objpfx)r$(start-installed-name)): New. ($(objpfx)g$(start-installed-name)): Also depend on $(objpfx)static-reloc.os. ($(objpfx)gr$(start-installed-name)): New. * csu/libc-start.c (LIBC_START_MAIN): Call _dl_relocate_static_pie in libc.a. * csu/libc-tls.c (__libc_setup_tls): Add main_map->l_addr to initimage. * csu/static-reloc.c: New file. * elf/Makefile (routines): Add dl-reloc-static-pie. (elide-routines.os): Likewise. (DEFAULT-LDFLAGS-tst-tls1-static-non-pie): Removed. (tst-tls1-static-non-pie-no-pie): New. * elf/dl-reloc-static-pie.c: New file. * elf/dl-support.c (_dl_get_dl_main_map): New function. * elf/dynamic-link.h (ELF_DURING_STARTUP): Also check STATIC_PIE_BOOTSTRAP. * elf/get-dynamic-info.h (elf_get_dynamic_info): Likewise. * gmon/Makefile (tests): Add tst-gmon-static-pie. (tests-static): Likewise. (DEFAULT-LDFLAGS-tst-gmon-static): Removed. (tst-gmon-static-no-pie): New. (CFLAGS-tst-gmon-static-pie.c): Likewise. (CRT-tst-gmon-static-pie): Likewise. (tst-gmon-static-pie-ENV): Likewise. (tests-special): Likewise. ($(objpfx)tst-gmon-static-pie.out): Likewise. (clean-tst-gmon-static-pie-data): Likewise. ($(objpfx)tst-gmon-static-pie-gprof.out): Likewise. * gmon/tst-gmon-static-pie.c: New file. * manual/install.texi: Document --enable-static-pie. * sysdeps/generic/ldsodefs.h (_dl_relocate_static_pie): New. (_dl_get_dl_main_map): Likewise. * sysdeps/i386/configure.ac: Check if linker supports static PIE. * sysdeps/x86_64/configure.ac: Likewise. * sysdeps/i386/configure: Regenerated. * sysdeps/x86_64/configure: Likewise. * sysdeps/mips/Makefile (ASFLAGS-.o): Add $(pie-default). (ASFLAGS-.op): Likewise. --- INSTALL | 9 ++++++ Makeconfig | 38 +++++++++++++++++++--- NEWS | 9 ++++++ config.h.in | 3 ++ configure | 79 +++++++++++++++++++++++++++++++++++++++++++++ configure.ac | 29 +++++++++++++++++ csu/Makefile | 24 ++++++++++++-- csu/libc-start.c | 2 ++ csu/libc-tls.c | 6 ++-- csu/static-reloc.c | 26 +++++++++++++++ elf/Makefile | 7 ++-- elf/dl-reloc-static-pie.c | 52 +++++++++++++++++++++++++++++ elf/dl-support.c | 11 +++++++ elf/dynamic-link.h | 2 +- elf/get-dynamic-info.h | 6 ++-- gmon/Makefile | 25 +++++++++++++- gmon/tst-gmon-static-pie.c | 1 + manual/install.texi | 9 ++++++ sysdeps/generic/ldsodefs.h | 11 +++++++ sysdeps/i386/configure | 33 +++++++++++++++++++ sysdeps/i386/configure.ac | 23 +++++++++++++ sysdeps/mips/Makefile | 3 ++ sysdeps/x86_64/configure | 33 +++++++++++++++++++ sysdeps/x86_64/configure.ac | 25 ++++++++++++++ 24 files changed, 449 insertions(+), 17 deletions(-) create mode 100644 csu/static-reloc.c create mode 100644 elf/dl-reloc-static-pie.c create mode 100644 gmon/tst-gmon-static-pie.c diff --git a/INSTALL b/INSTALL index d1a34c2a90..30804eca38 100644 --- a/INSTALL +++ b/INSTALL @@ -90,6 +90,15 @@ will be used, and CFLAGS sets optimization options for the compiler. systems support shared libraries; you need ELF support and (currently) the GNU linker. +'--enable-static-pie' + Enable static position independent executable (static PIE) support. + Static PIE is similar to static executable, but can be loaded at + any address without help from a dynamic linker. All static + programs as well as static tests are built as static PIE, except + for those marked with no-pie. The resulting glibc can be used with + the GCC option, -static-pie, which is available with GCC 8 or + above, to create static PIE. + '--disable-profile' Don't build libraries with profiling information. You may want to use this option if you don't plan to do profiling. diff --git a/Makeconfig b/Makeconfig index 1346109ac0..99cc136bfa 100644 --- a/Makeconfig +++ b/Makeconfig @@ -352,6 +352,14 @@ ifndef static-start-installed-name static-start-installed-name = $(start-installed-name) endif +ifeq (yes,$(enable-static-pie)) +# Link with rcrt1.o, instead of crt1.o, to call _dl_relocate_static_pie +# to relocate static PIE. +real-static-start-installed-name = r$(static-start-installed-name) +else +real-static-start-installed-name = $(static-start-installed-name) +endif + ifeq (yesyes,$(build-shared)$(have-z-combreloc)) combreloc-LDFLAGS = -Wl,-z,combreloc LDFLAGS.so += $(combreloc-LDFLAGS) @@ -371,6 +379,20 @@ LDFLAGS.so += $(hashstyle-LDFLAGS) LDFLAGS-rtld += $(hashstyle-LDFLAGS) endif +ifeq (yes,$(enable-static-pie)) +pic-default = -DPIC +# Compile libc.a and libc_p.a with -fPIE/-fpie for static PIE. +pie-default = $(pie-ccflag) +ifeq (yes,$(have-static-pie)) +default-pie-ldflag = -static-pie +else +# Static PIE can't have dynamic relocations in read-only segments since +# static PIE is mapped into memory by kernel. --eh-frame-hdr is needed +# for PIE to support exception. +default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text +endif +endif + # If lazy relocations are disabled, add the -z now flag. Use # LDFLAGS-lib.so instead of LDFLAGS.so, to avoid adding the flag to # test modules. @@ -420,9 +442,9 @@ endif # Command for statically linking programs with the C library. ifndef +link-static +link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \ - $(DEFAULT-LDFLAGS-$(@F)) \ + $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)) \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ - $(firstword $(CRT-$(@F)) $(csu-objpfx)$(static-start-installed-name)) \ + $(firstword $(CRT-$(@F)) $(csu-objpfx)$(real-static-start-installed-name)) \ $(+preinit) $(+prectorT) \ $(filter-out $(addprefix $(csu-objpfx),start.o \ $(start-installed-name))\ @@ -637,8 +659,14 @@ endif +prectorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginS.o` +postctorS = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtendS.o` # Variants of the two previous definitions for statically linking programs. +ifeq (yes,$(enable-static-pie)) +# Static PIE must use PIE variants. ++prectorT = $(+prectorS) ++postctorT = $(+postctorS) +else +prectorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtbeginT.o` +postctorT = `$(CC) $(sysdep-LDFLAGS) --print-file-name=crtend.o` +endif csu-objpfx = $(common-objpfx)csu/ elf-objpfx = $(common-objpfx)elf/ @@ -959,7 +987,8 @@ libtypes = $(foreach o,$(object-suffixes-for-libc),$(libtype$o)) all-object-suffixes := .o .os .oS object-suffixes := CPPFLAGS-.o = $(pic-default) -CFLAGS-.o = $(filter %frame-pointer,$(+cflags)) +# libc.a must be compiled with -fPIE/-fpie for static PIE. +CFLAGS-.o = $(filter %frame-pointer,$(+cflags)) $(pie-default) libtype.o := lib%.a object-suffixes += .o ifeq (yes,$(build-shared)) @@ -984,7 +1013,8 @@ ifeq (yes,$(build-profile)) all-object-suffixes += .op object-suffixes += .op CPPFLAGS-.op = -DPROF $(pic-default) -CFLAGS-.op = -pg +# libc_p.a must be compiled with -fPIE/-fpie for static PIE. +CFLAGS-.op = -pg $(pie-default) libtype.op = lib%_p.a endif diff --git a/NEWS b/NEWS index 48af4acaea..5b09359f2c 100644 --- a/NEWS +++ b/NEWS @@ -9,6 +9,15 @@ Version 2.27 Major new features: +* The GNU C Library can now be compiled with support for building static + PIE executables (See --enable-static-pie in INSTALL). These static PIE + exectuables are like static executables but can be loaded at any address + and provide additional security hardening benefits at the cost of some + memory and performance. When the library is built with --enable-static-pie + the resulting libc.a is usable with GCC 8 and above to create static PIE + executables using the GCC option '-static-pie'. This feature is currently + supported on i386, x86_64 and x32. + * Optimized x86-64 asin, atan2, exp, expf, log, pow, atan, sin and tan with FMA, contributed by Arjan van de Ven and H.J. Lu from Intel. diff --git a/config.h.in b/config.h.in index 8d76dadca2..0ecb10939f 100644 --- a/config.h.in +++ b/config.h.in @@ -241,6 +241,9 @@ /* Build glibc with tunables support. */ #define HAVE_TUNABLES 0 +/* Define if static PIE is enabled. */ +#define ENABLE_STATIC_PIE 0 + /* Some compiler options may now allow to use ebp in __asm__ (used mainly in i386 6 argument syscall issue). */ #define CAN_USE_REGISTER_ASM_EBP 0 diff --git a/configure b/configure index caba102846..d4dfb90a38 100755 --- a/configure +++ b/configure @@ -765,6 +765,7 @@ with_default_link enable_sanity_checks enable_shared enable_profile +enable_static_pie enable_timezone_tools enable_hardcoded_path_in_tests enable_stackguard_randomization @@ -1420,6 +1421,8 @@ Optional Features: in special situations) [default=yes] --enable-shared build shared library [default=yes if GNU ld] --enable-profile build profiled library [default=no] + --enable-static-pie enable static PIE support and use it in the + testsuite [default=no] --disable-timezone-tools do not install timezone tools [default=install] --enable-hardcoded-path-in-tests @@ -3365,6 +3368,13 @@ else profile=no fi +# Check whether --enable-static-pie was given. +if test "${enable_static_pie+set}" = set; then : + enableval=$enable_static_pie; static_pie=$enableval +else + static_pie=no +fi + # Check whether --enable-timezone-tools was given. if test "${enable_timezone_tools+set}" = set; then : enableval=$enable_timezone_tools; enable_timezone_tools=$enableval @@ -5805,6 +5815,62 @@ fi $as_echo "$libc_linker_feature" >&6; } +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker that supports --no-dynamic-linker" >&5 +$as_echo_n "checking for linker that supports --no-dynamic-linker... " >&6; } +libc_linker_feature=no +if test x"$gnu_ld" = x"yes"; then + libc_linker_check=`$LD -v --help 2>/dev/null | grep "\--no-dynamic-linker"` + if test -n "$libc_linker_check"; then + cat > conftest.c <&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; } + then + libc_linker_feature=yes + fi + rm -f conftest* + fi +fi +if test $libc_linker_feature = yes; then + libc_cv_no_dynamic_linker=yes +else + libc_cv_no_dynamic_linker=no +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 +$as_echo "$libc_linker_feature" >&6; } +config_vars="$config_vars +have-no-dynamic-linker = $libc_cv_no_dynamic_linker" + +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -static-pie" >&5 +$as_echo_n "checking for -static-pie... " >&6; } +if ${libc_cv_static_pie+:} false; then : + $as_echo_n "(cached) " >&6 +else + if { ac_try='${CC-cc} -static-pie -xc /dev/null -S -o /dev/null' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; }; then : + libc_cv_static_pie=yes +else + libc_cv_static_pie=no +fi + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie" >&5 +$as_echo "$libc_cv_static_pie" >&6; } +config_vars="$config_vars +have-static-pie = $libc_cv_static_pie" + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -fpie" >&5 $as_echo_n "checking for -fpie... " >&6; } if ${libc_cv_fpie+:} false; then : @@ -6704,6 +6770,19 @@ $as_echo "$libc_cv_pie_default" >&6; } libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` +if test "$static_pie" = yes; then + # The linker must support --no-dynamic-linker. + if test "$libc_cv_no_dynamic_linker" != yes; then + as_fn_error $? "linker support for --no-dynamic-linker needed" "$LINENO" 5 + fi + # Default to PIE. + libc_cv_pie_default=yes + $as_echo "#define ENABLE_STATIC_PIE 1" >>confdefs.h + +fi +config_vars="$config_vars +enable-static-pie = $static_pie" + diff --git a/configure.ac b/configure.ac index 9707ae4d8e..78564f3746 100644 --- a/configure.ac +++ b/configure.ac @@ -176,6 +176,11 @@ AC_ARG_ENABLE([profile], [build profiled library @<:@default=no@:>@]), [profile=$enableval], [profile=no]) +AC_ARG_ENABLE([static-pie], + AC_HELP_STRING([--enable-static-pie], + [enable static PIE support and use it in the testsuite @<:@default=no@:>@]), + [static_pie=$enableval], + [static_pie=no]) AC_ARG_ENABLE([timezone-tools], AC_HELP_STRING([--disable-timezone-tools], [do not install timezone tools @<:@default=install@:>@]), @@ -1280,6 +1285,19 @@ LIBC_LINKER_FEATURE([-z execstack], [-Wl,-z,execstack], [libc_cv_z_execstack=yes], [libc_cv_z_execstack=no]) AC_SUBST(libc_cv_z_execstack) +LIBC_LINKER_FEATURE([--no-dynamic-linker], + [-Wl,--no-dynamic-linker], + [libc_cv_no_dynamic_linker=yes], + [libc_cv_no_dynamic_linker=no]) +LIBC_CONFIG_VAR([have-no-dynamic-linker], [$libc_cv_no_dynamic_linker]) + +AC_CACHE_CHECK(for -static-pie, libc_cv_static_pie, [dnl +LIBC_TRY_CC_OPTION([-static-pie], + [libc_cv_static_pie=yes], + [libc_cv_static_pie=no]) +]) +LIBC_CONFIG_VAR([have-static-pie], [$libc_cv_static_pie]) + AC_CACHE_CHECK(for -fpie, libc_cv_fpie, [dnl LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no]) ]) @@ -1787,6 +1805,17 @@ AC_SUBST(libc_cv_pie_default) libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` AC_SUBST(libc_cv_multidir) +if test "$static_pie" = yes; then + # The linker must support --no-dynamic-linker. + if test "$libc_cv_no_dynamic_linker" != yes; then + AC_MSG_ERROR([linker support for --no-dynamic-linker needed]) + fi + # Default to PIE. + libc_cv_pie_default=yes + AC_DEFINE(ENABLE_STATIC_PIE) +fi +LIBC_CONFIG_VAR([enable-static-pie], [$static_pie]) + AC_SUBST(profile) AC_SUBST(static_nss) diff --git a/csu/Makefile b/csu/Makefile index e42a32b3eb..86b95a9759 100644 --- a/csu/Makefile +++ b/csu/Makefile @@ -37,7 +37,9 @@ extra-objs = start.o \ S$(start-installed-name) omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \ b$(start-installed-name) $(csu-dummies) \ - S$(start-installed-name)) + S$(start-installed-name) \ + r$(start-installed-name) \ + gr$(start-installed-name)) install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies) # No tests are allowed in the csu/ subdirectory because the startup @@ -60,10 +62,17 @@ extra-objs += gmon-start.o endif ifneq ($(start-installed-name),$(static-start-installed-name)) +# FIXME: Only Hurd defines static-start-installed-name. Hurd needs to +# provide special rules to support static PIE. extra-objs += $(static-start-installed-name) g$(static-start-installed-name) omit-deps += $(patsubst %.o,%,$(static-start-installed-name) \ g$(static-start-installed-name)) install-lib += $(static-start-installed-name) g$(static-start-installed-name) +else +ifeq (yes,$(enable-static-pie)) +extra-objs += r$(start-installed-name) gr$(start-installed-name) +install-lib += r$(start-installed-name) gr$(start-installed-name) +endif endif before-compile += $(objpfx)abi-tag.h @@ -82,7 +91,10 @@ multilib-extra-objs = $(addprefix $(multidir)/, $(install-lib)) extra-objs += $(multilib-extra-objs) endif -extra-objs += abi-note.o init.o +extra-objs += abi-note.o init.o static-reloc.o +ifeq (yes,$(build-shared)) +extra-objs += static-reloc.os +endif asm-CPPFLAGS += -I$(objpfx). # Enable unwinding so backtrace unwinds to __libc_start_main @@ -101,6 +113,9 @@ ifndef start-installed-name-rule # We link the ELF startfile along with a SHT_NOTE section indicating # the kernel ABI the binaries linked with this library will require. $(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \ + $(objpfx)init.o $(objpfx)static-reloc.o + $(link-relocatable) +$(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \ $(objpfx)init.o $(link-relocatable) $(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \ @@ -113,7 +128,10 @@ endif # to turn on profiling code at startup. ifeq (yes,$(build-shared)) $(objpfx)g$(start-installed-name): \ - $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os + $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os $(objpfx)static-reloc.os + $(link-relocatable) +$(objpfx)gr$(start-installed-name): \ + $(objpfx)gr%: $(objpfx)r% $(objpfx)gmon-start.o $(link-relocatable) ifneq ($(start-installed-name),$(static-start-installed-name)) $(objpfx)g$(static-start-installed-name): \ diff --git a/csu/libc-start.c b/csu/libc-start.c index 24c63be02f..34dd125260 100644 --- a/csu/libc-start.c +++ b/csu/libc-start.c @@ -141,6 +141,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up; #ifndef SHARED + _dl_relocate_static_pie (); + char **ev = &argv[argc + 1]; __environ = ev; diff --git a/csu/libc-tls.c b/csu/libc-tls.c index 00138eb43a..1f8ddaf543 100644 --- a/csu/libc-tls.c +++ b/csu/libc-tls.c @@ -114,6 +114,8 @@ __libc_setup_tls (void) size_t tcb_offset; const ElfW(Phdr) *phdr; + struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; + /* Look through the TLS segment if there is any. */ if (_dl_phdr != NULL) for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr) @@ -122,7 +124,7 @@ __libc_setup_tls (void) /* Remember the values we need. */ memsz = phdr->p_memsz; filesz = phdr->p_filesz; - initimage = (void *) phdr->p_vaddr; + initimage = (void *) phdr->p_vaddr + main_map->l_addr; align = phdr->p_align; if (phdr->p_align > max_align) max_align = phdr->p_align; @@ -163,8 +165,6 @@ __libc_setup_tls (void) _dl_static_dtv[0].counter = (sizeof (_dl_static_dtv) / sizeof (_dl_static_dtv[0])) - 2; // _dl_static_dtv[1].counter = 0; would be needed if not already done - struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; - /* Initialize the TLS block. */ #if TLS_TCB_AT_TP _dl_static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset diff --git a/csu/static-reloc.c b/csu/static-reloc.c new file mode 100644 index 0000000000..37be72c8ea --- /dev/null +++ b/csu/static-reloc.c @@ -0,0 +1,26 @@ +/* Special startup support for non-PIE static executables. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#if ENABLE_STATIC_PIE +#include + +void +_dl_relocate_static_pie (void) +{ +} +#endif diff --git a/elf/Makefile b/elf/Makefile index d49fd4673d..4c6f9e0a49 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -24,7 +24,8 @@ include ../Makeconfig headers = elf.h bits/elfclass.h link.h bits/link.h routines = $(all-dl-routines) dl-support dl-iteratephdr \ dl-addr dl-addr-obj enbl-secure dl-profstub \ - dl-origin dl-libc dl-sym dl-sysdep dl-error + dl-origin dl-libc dl-sym dl-sysdep dl-error \ + dl-reloc-static-pie # The core dynamic linking functions are in libc for the static and # profiled libraries. @@ -52,7 +53,7 @@ endif all-dl-routines = $(dl-routines) $(sysdep-dl-routines) # But they are absent from the shared libc, because that code is in ld.so. elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \ - dl-sysdep dl-exception + dl-sysdep dl-exception dl-reloc-static-pie shared-only-routines += dl-caller # ld.so uses those routines, plus some special stuff for being the program @@ -153,7 +154,7 @@ tests-static-internal := tst-tls1-static tst-tls2-static \ tst-tls1-static-non-pie CRT-tst-tls1-static-non-pie := $(csu-objpfx)crt1.o -DEFAULT-LDFLAGS-tst-tls1-static-non-pie = $(no-pie-ldflag) +tst-tls1-static-non-pie-no-pie = yes tests := tst-tls9 tst-leaks1 \ tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \ diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c new file mode 100644 index 0000000000..6e43aea76a --- /dev/null +++ b/elf/dl-reloc-static-pie.c @@ -0,0 +1,52 @@ +/* Support for relocating static PIE. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#if ENABLE_STATIC_PIE +#include +#include +#include "dynamic-link.h" + +/* Relocate static executable with PIE. */ + +void +_dl_relocate_static_pie (void) +{ + struct link_map *main_map = _dl_get_dl_main_map (); + +# define STATIC_PIE_BOOTSTRAP +# define BOOTSTRAP_MAP (main_map) +# define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP +# include "dynamic-link.h" + + /* Figure out the run-time load address of static PIE. */ + main_map->l_addr = elf_machine_load_address (); + + /* Read our own dynamic section and fill in the info array. */ + main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); + elf_get_dynamic_info (main_map, NULL); + +# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC + ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info); +# endif + + /* Relocate ourselves so we can do normal function calls and + data access using the global offset table. */ + ELF_DYNAMIC_RELOCATE (main_map, 0, 0, 0); + main_map->l_relocated = 1; +} +#endif diff --git a/elf/dl-support.c b/elf/dl-support.c index 235d3a7f46..b9fc1a66fe 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -385,3 +385,14 @@ _dl_non_dynamic_init (void) #ifdef DL_SYSINFO_IMPLEMENTATION DL_SYSINFO_IMPLEMENTATION #endif + +#if ENABLE_STATIC_PIE +/* Since relocation to hidden _dl_main_map causes relocation overflow on + aarch64, a function is used to get the address of _dl_main_map. */ + +struct link_map * +_dl_get_dl_main_map (void) +{ + return &_dl_main_map; +} +#endif diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h index ebea7567cd..6278649711 100644 --- a/elf/dynamic-link.h +++ b/elf/dynamic-link.h @@ -94,7 +94,7 @@ elf_machine_lazy_rel (struct link_map *map, #ifdef RESOLVE_MAP -# ifdef RTLD_BOOTSTRAP +# if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP # define ELF_DURING_STARTUP (1) # else # define ELF_DURING_STARTUP (0) diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h index 7525c3a5b2..eb26d23649 100644 --- a/elf/get-dynamic-info.h +++ b/elf/get-dynamic-info.h @@ -38,7 +38,7 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp) typedef Elf64_Xword d_tag_utype; #endif -#ifndef RTLD_BOOTSTRAP +#if !defined RTLD_BOOTSTRAP && !defined STATIC_PIE_BOOTSTRAP if (dyn == NULL) return; #endif @@ -139,9 +139,11 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp) /* Only the bind now flags are allowed. */ assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0); + /* Flags must not be set for ld.so. */ assert (info[DT_FLAGS] == NULL || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0); - /* Flags must not be set for ld.so. */ +#endif +#if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP assert (info[DT_RUNPATH] == NULL); assert (info[DT_RPATH] == NULL); #else diff --git a/gmon/Makefile b/gmon/Makefile index 89ab3fc7da..29e746723e 100644 --- a/gmon/Makefile +++ b/gmon/Makefile @@ -39,6 +39,10 @@ tests-static += tst-gmon-static ifeq (yesyes,$(have-fpie)$(build-shared)) tests += tst-gmon-pie tests-pie += tst-gmon-pie +ifeq (yes,$(enable-static-pie)) +tests += tst-gmon-static-pie +tests-static += tst-gmon-static-pie +endif endif # The mcount code won't work without a frame pointer. @@ -54,7 +58,7 @@ endif CFLAGS-tst-gmon-static.c := $(PIE-ccflag) -fno-omit-frame-pointer -pg CRT-tst-gmon-static := $(csu-objpfx)gcrt1.o -DEFAULT-LDFLAGS-tst-gmon-static = $(no-pie-ldflag) +tst-gmon-static-no-pie = yes tst-gmon-static-ENV := GMON_OUT_PREFIX=$(objpfx)tst-gmon-static.data ifeq ($(run-built-tests),yes) tests-special += $(objpfx)tst-gmon-static-gprof.out @@ -67,6 +71,15 @@ ifeq ($(run-built-tests),yes) tests-special += $(objpfx)tst-gmon-pie-gprof.out endif +ifeq (yes,$(enable-static-pie)) +CFLAGS-tst-gmon-static-pie.c := $(PIE-ccflag) -fno-omit-frame-pointer -pg +CRT-tst-gmon-static-pie := $(csu-objpfx)grcrt1.o +tst-gmon-static-pie-ENV := GMON_OUT_PREFIX=$(objpfx)tst-gmon-static-pie.data +ifeq ($(run-built-tests),yes) +tests-special += $(objpfx)tst-gmon-static-pie-gprof.out +endif +endif + include ../Rules @@ -111,3 +124,13 @@ clean-tst-gmon-pie-data: $(objpfx)tst-gmon-pie-gprof.out: tst-gmon-gprof.sh $(objpfx)tst-gmon-pie.out $(SHELL) $< $(GPROF) $(objpfx)tst-gmon-pie $(objpfx)tst-gmon-pie.data.* > $@; \ $(evaluate-test) + +$(objpfx)tst-gmon-static-pie.out: clean-tst-gmon-static-pie-data +clean-tst-gmon-static-pie-data: + rm -f $(objpfx)tst-gmon-static-pie.data.* + +$(objpfx)tst-gmon-static-pie-gprof.out: tst-gmon-static-gprof.sh \ + $(objpfx)tst-gmon-static-pie.out + $(SHELL) $< $(GPROF) $(objpfx)tst-gmon-static-pie \ + $(objpfx)tst-gmon-static-pie.data.* > $@; \ + $(evaluate-test) diff --git a/gmon/tst-gmon-static-pie.c b/gmon/tst-gmon-static-pie.c new file mode 100644 index 0000000000..1eef2583b6 --- /dev/null +++ b/gmon/tst-gmon-static-pie.c @@ -0,0 +1 @@ +#include "tst-gmon.c" diff --git a/manual/install.texi b/manual/install.texi index ea559e4e72..0efa8572df 100644 --- a/manual/install.texi +++ b/manual/install.texi @@ -120,6 +120,15 @@ Don't build shared libraries even if it is possible. Not all systems support shared libraries; you need ELF support and (currently) the GNU linker. +@item --enable-static-pie +Enable static position independent executable (static PIE) support. +Static PIE is similar to static executable, but can be loaded at any +address without help from a dynamic linker. All static programs as +well as static tests are built as static PIE, except for those marked +with no-pie. The resulting glibc can be used with the GCC option, +-static-pie, which is available with GCC 8 or above, to create static +PIE. + @item --disable-profile Don't build libraries with profiling information. You may want to use this option if you don't plan to do profiling. diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 7a65dc641c..196513851f 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -1051,6 +1051,17 @@ extern void _dl_determine_tlsoffset (void) attribute_hidden; stack protector, among other things). */ void __libc_setup_tls (void); +# if ENABLE_STATIC_PIE +/* Relocate static executable with PIE. */ +extern void _dl_relocate_static_pie (void) attribute_hidden; + +/* Get a pointer to _dl_main_map. */ +extern struct link_map * _dl_get_dl_main_map (void) + __attribute__ ((visibility ("hidden"))); +# else +# define _dl_relocate_static_pie() +# endif + /* Initialization of libpthread for statically linked applications. If libpthread is not linked in, this is an empty function. */ void __pthread_initialize_minimal (void) weak_function; diff --git a/sysdeps/i386/configure b/sysdeps/i386/configure index 4cf968d8bc..90c63caf35 100644 --- a/sysdeps/i386/configure +++ b/sysdeps/i386/configure @@ -50,6 +50,39 @@ fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_compiler_builtin_inlined" >&5 $as_echo "$libc_compiler_builtin_inlined" >&6; } +if test "$static_pie" = yes; then + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker static PIE support" >&5 +$as_echo_n "checking for linker static PIE support... " >&6; } +if ${libc_cv_ld_static_pie+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat > conftest.s <<\EOF + .text + .global _start +_start: + movl _start@GOT(%ebx), %eax +EOF + libc_cv_pie_option="-Wl,-pie" + libc_cv_ld_static_pie=no + if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&5' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; }; then + if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then + libc_cv_ld_static_pie=yes + fi + fi +rm -f conftest* +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_static_pie" >&5 +$as_echo "$libc_cv_ld_static_pie" >&6; } + if test "$libc_cv_ld_static_pie" != yes; then + as_fn_error $? "linker support for static PIE needed" "$LINENO" 5 + fi +fi + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for Intel MPX support" >&5 $as_echo_n "checking for Intel MPX support... " >&6; } if ${libc_cv_asm_mpx+:} false; then : diff --git a/sysdeps/i386/configure.ac b/sysdeps/i386/configure.ac index b598b120bc..6d2068d2b3 100644 --- a/sysdeps/i386/configure.ac +++ b/sysdeps/i386/configure.ac @@ -30,6 +30,29 @@ LIBC_COMPILER_BUILTIN_INLINED( *** Please use host i786, i686, i586, or i486. *** For example: /source/glibc/configure CFLAGS='-O2 -march=i686' ...])]) +dnl Check if linker can convert "movl main@GOT(%ebx), %eax" to +dnl "leal main@GOTOFF(%ebx), %eax" for static PIE. +if test "$static_pie" = yes; then + AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl +cat > conftest.s <<\EOF + .text + .global _start +_start: + movl _start@GOT(%ebx), %eax +EOF + libc_cv_pie_option="-Wl,-pie" + libc_cv_ld_static_pie=no + if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then + if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then + libc_cv_ld_static_pie=yes + fi + fi +rm -f conftest*]) + if test "$libc_cv_ld_static_pie" != yes; then + AC_MSG_ERROR([linker support for static PIE needed]) + fi +fi + dnl Check whether asm supports Intel MPX AC_CACHE_CHECK(for Intel MPX support, libc_cv_asm_mpx, [dnl cat > conftest.s <<\EOF diff --git a/sysdeps/mips/Makefile b/sysdeps/mips/Makefile index fd891ddf09..7ac6fa5031 100644 --- a/sysdeps/mips/Makefile +++ b/sysdeps/mips/Makefile @@ -23,6 +23,9 @@ CPPFLAGS-crtn.S += $(pic-ccflag) endif ASFLAGS-.os += $(pic-ccflag) +# libc.a and libc_p.a must be compiled with -fPIE/-fpie for static PIE. +ASFLAGS-.o += $(pie-default) +ASFLAGS-.op += $(pie-default) ifeq ($(subdir),elf) ifneq ($(o32-fpabi),) diff --git a/sysdeps/x86_64/configure b/sysdeps/x86_64/configure index efef46b1b7..8674d14569 100644 --- a/sysdeps/x86_64/configure +++ b/sysdeps/x86_64/configure @@ -85,6 +85,39 @@ if test x"$build_mathvec" = xnotset; then build_mathvec=yes fi +if test "$static_pie" = yes; then + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker static PIE support" >&5 +$as_echo_n "checking for linker static PIE support... " >&6; } +if ${libc_cv_ld_static_pie+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat > conftest.s <<\EOF + .text + .global _start + .weak foo +_start: + leaq foo(%rip), %rax +EOF + libc_cv_pie_option="-Wl,-pie" + if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&5' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; }; then + libc_cv_ld_static_pie=yes + else + libc_cv_ld_static_pie=no + fi +rm -f conftest* +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_static_pie" >&5 +$as_echo "$libc_cv_ld_static_pie" >&6; } + if test "$libc_cv_ld_static_pie" != yes; then + as_fn_error $? "linker support for static PIE needed" "$LINENO" 5 + fi +fi + $as_echo "#define PI_STATIC_AND_HIDDEN 1" >>confdefs.h diff --git a/sysdeps/x86_64/configure.ac b/sysdeps/x86_64/configure.ac index fa86e953ee..b7d2c0124f 100644 --- a/sysdeps/x86_64/configure.ac +++ b/sysdeps/x86_64/configure.ac @@ -44,6 +44,31 @@ if test x"$build_mathvec" = xnotset; then build_mathvec=yes fi +dnl Check if linker supports static PIE with the fix for +dnl +dnl https://sourceware.org/bugzilla/show_bug.cgi?id=21782 +dnl +if test "$static_pie" = yes; then + AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl +cat > conftest.s <<\EOF + .text + .global _start + .weak foo +_start: + leaq foo(%rip), %rax +EOF + libc_cv_pie_option="-Wl,-pie" + if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then + libc_cv_ld_static_pie=yes + else + libc_cv_ld_static_pie=no + fi +rm -f conftest*]) + if test "$libc_cv_ld_static_pie" != yes; then + AC_MSG_ERROR([linker support for static PIE needed]) + fi +fi + dnl It is always possible to access static and hidden symbols in an dnl position independent way. AC_DEFINE(PI_STATIC_AND_HIDDEN) -- 2.14.3