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(localhost [IPv6:::1]) by gnu-tgl-3.localdomain (Postfix) with ESMTP id 1BBF1C0322 for ; Mon, 16 May 2022 06:17:14 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v2] Enable DT_RELR in glibc shared libraries and PIEs automatically Date: Mon, 16 May 2022 06:17:14 -0700 Message-Id: <20220516131714.37463-1-hjl.tools@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 X-Spam-Status: No, score=-3028.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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: "H.J. Lu via Libc-alpha" From: "H.J. Lu" Reply-To: "H.J. Lu" Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" Enable DT_RELR in glibc shared libraries and position independent executables (PIE) automatically if linker supports -z pack-relative-relocs. Reviewed-by: Florian Weimer --- Makeconfig | 12 ++++++++++++ Makerules | 2 ++ elf/Makefile | 5 ++++- 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/Makeconfig b/Makeconfig index 760f14e92f..c87d644044 100644 --- a/Makeconfig +++ b/Makeconfig @@ -362,6 +362,15 @@ relro-LDFLAGS = -Wl,-z,relro LDFLAGS.so += $(relro-LDFLAGS) LDFLAGS-rtld += $(relro-LDFLAGS) +# Linker options to enable and disable DT_RELR. +ifeq ($(have-dt-relr),yes) +dt-relr-ldflag = -Wl,-z,pack-relative-relocs +no-dt-relr-ldflag = -Wl,-z,nopack-relative-relocs +else +dt-relr-ldflag = +no-dt-relr-ldflag = +endif + ifeq (no,$(build-pie-default)) pie-default = $(no-pie-ccflag) else # build-pie-default @@ -370,6 +379,7 @@ pic-default = -DPIC pie-default = $(pie-ccflag) ifeq (yes,$(enable-static-pie)) +static-pie-dt-relr-ldflag = $(dt-relr-ldflag) ifeq (yes,$(have-static-pie)) static-pie-ldflag = -static-pie else @@ -404,6 +414,7 @@ link-extra-libs-tests = $(libsupport) # Command for linking PIE programs with the C library. ifndef +link-pie +link-pie-before-inputs = $(if $($(@F)-no-pie),$(no-pie-ldflag),-pie) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(dt-relr-ldflag)) \ -Wl,-O1 -nostdlib -nostartfiles \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \ @@ -436,6 +447,7 @@ endif ifndef +link-static +link-static-before-inputs = -nostdlib -nostartfiles -static \ $(if $($(@F)-no-pie),$(no-pie-ldflag),$(static-pie-ldflag)) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(static-pie-dt-relr-ldflag)) \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ $(firstword $(CRT-$(@F)) $(csu-objpfx)$(real-static-start-installed-name)) \ $(+preinit) $(+prectorT) diff --git a/Makerules b/Makerules index 354528b8c7..dfe89e9e39 100644 --- a/Makerules +++ b/Makerules @@ -536,6 +536,7 @@ lib%.so: lib%_pic.a $(+preinit) $(+postinit) $(link-libc-deps) define build-shlib-helper $(LINK.o) -shared -static-libgcc -Wl,-O1 $(sysdep-LDFLAGS) \ $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) $(rtld-LDFLAGS) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(dt-relr-ldflag)) \ $(extra-B-$(@F:lib%.so=%).so) -B$(csu-objpfx) \ $(extra-B-$(@F:lib%.so=%).so) $(load-map-file) \ -Wl,-soname=lib$(libprefix)$(@F:lib%.so=%).so$($(@F)-version) \ @@ -588,6 +589,7 @@ endef define build-module-helper $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \ $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(dt-relr-ldflag)) \ -B$(csu-objpfx) $(load-map-file) \ $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \ $(link-test-modules-rpath-link) \ diff --git a/elf/Makefile b/elf/Makefile index fc9860edee..fa98e188df 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1335,6 +1335,7 @@ $(objpfx)ld.so: $(objpfx)librtld.os $(ld-map) # if the sanity check below fails. $(LINK.o) -nostdlib -nostartfiles -shared -o $@.new \ $(LDFLAGS-rtld) -Wl,-z,defs $(z-now-$(bind-now)) \ + $(dt-relr-ldflag) \ $(filter-out $(map-file),$^) $(load-map-file) \ -Wl,-soname=$(rtld-installed-name) $(call after-link,$@.new) @@ -1659,6 +1660,7 @@ $(objpfx)nodlopen2.out: $(objpfx)nodlopenmod2.so $(objpfx)filtmod1.so: $(objpfx)filtmod1.os $(objpfx)filtmod2.so $(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \ + $(dt-relr-ldflag) \ -L$(subst :, -L,$(rpath-link)) \ -Wl,-rpath-link=$(rpath-link) \ $< -Wl,-F,$(objpfx)filtmod2.so @@ -2462,7 +2464,7 @@ $(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so # artificial, large note in tst-big-note-lib.o and invalidate the # test. $(objpfx)tst-big-note-lib.so: $(objpfx)tst-big-note-lib.o - $(LINK.o) -shared -o $@ $(LDFLAGS.so) $< + $(LINK.o) -shared -o $@ $(LDFLAGS.so) $(dt-relr-ldflag) $< $(objpfx)tst-unwind-ctor: $(objpfx)tst-unwind-ctor-lib.so @@ -2771,6 +2773,7 @@ $(objpfx)tst-ro-dynamic: $(objpfx)tst-ro-dynamic-mod.so $(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \ tst-ro-dynamic-mod.map $(LINK.o) -nostdlib -nostartfiles -shared -o $@ \ + $(dt-relr-ldflag) \ -Wl,--script=tst-ro-dynamic-mod.map \ $(objpfx)tst-ro-dynamic-mod.os