From 02d2d8927d2fd3815a9f3c5c767aa71a8a33408e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 3 Oct 2017 17:48:55 -0700 Subject: [PATCH] Revert x86: Allow undefined _DYNAMIC in static executable This code is used in non-PIE static executable and static PIE. It checks if _DYNAMIC is undefined before using it to compute load address. But not all targets can convert access _DYNAMIC via GOT, which needs dynamic relocation, to PC-relative at link-time. * sysdeps/i386/dl-machine.h (elf_machine_load_address): Don't allow undefined _DYNAMIC in PIE libc.a. * sysdeps/x86_64/dl-machine.h (elf_machine_load_address): Likewse. --- ChangeLog | 7 +++++++ sysdeps/i386/dl-machine.h | 11 ++--------- sysdeps/x86_64/dl-machine.h | 11 ++--------- 3 files changed, 11 insertions(+), 18 deletions(-) diff --git a/ChangeLog b/ChangeLog index 581a926106c..01517c5514d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2017-10-03 H.J. Lu + + * sysdeps/i386/dl-machine.h (elf_machine_load_address): Don't + allow undefined _DYNAMIC in PIE libc.a. + * sysdeps/x86_64/dl-machine.h (elf_machine_load_address): + Likewse. + 2017-10-03 H.J. Lu * sysdeps/mips/dl-machine.h (elf_machine_load_address): Don't diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h index 242c692c17a..2e17eba5c08 100644 --- a/sysdeps/i386/dl-machine.h +++ b/sysdeps/i386/dl-machine.h @@ -54,15 +54,8 @@ elf_machine_load_address (void) /* Compute the difference between the runtime address of _DYNAMIC as seen by a GOTOFF reference, and the link-time address found in the special unrelocated first GOT entry. */ -#ifndef SHARED - extern Elf32_Dyn _DYNAMIC[] __attribute__((weak, visibility ("hidden"))); - if (!_DYNAMIC) - return 0; -#endif - /* The address of dynamic must be taken as non-weak to avoid dynamic - relocation. */ - extern Elf32_Dyn dynamic[] asm ("_DYNAMIC") attribute_hidden; - return (Elf32_Addr) &dynamic - elf_machine_dynamic (); + extern Elf32_Dyn bygotoff[] asm ("_DYNAMIC") attribute_hidden; + return (Elf32_Addr) &bygotoff - elf_machine_dynamic (); } /* Set up the loaded object described by L so its unrelocated PLT diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h index a79e5ca2f9e..6a04cbcdc98 100644 --- a/sysdeps/x86_64/dl-machine.h +++ b/sysdeps/x86_64/dl-machine.h @@ -55,15 +55,8 @@ elf_machine_load_address (void) /* Compute the difference between the runtime address of _DYNAMIC as seen by an IP-relative reference, and the link-time address found in the special unrelocated first GOT entry. */ -#ifndef SHARED - extern ElfW(Dyn) _DYNAMIC[] __attribute__((weak, visibility ("hidden"))); - if (!_DYNAMIC) - return 0; -#endif - /* The address of dynamic must be taken as non-weak to avoid dynamic - relocation. */ - extern ElfW(Dyn) dynamic[] asm ("_DYNAMIC") attribute_hidden; - return (ElfW(Addr)) &dynamic - elf_machine_dynamic (); + extern ElfW(Dyn) _DYNAMIC[] attribute_hidden; + return (ElfW(Addr)) &_DYNAMIC - elf_machine_dynamic (); } /* Set up the loaded object described by L so its unrelocated PLT -- 2.47.2