From 661b504df9bfb8d7c5d669091720e1dc0079c05e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 8 Jul 2021 13:49:17 -0700 Subject: [PATCH] x86-64: Disallow PC reloc against weak undefined symbols in PIE Disallow PC relocations against weak undefined symbols in PIE since they can lead to non-zero address at run-time. bfd/ PR ld/21782 * elf64-x86-64.c (elf_x86_64_relocate_section): Disallow PC relocations against weak undefined symbols in PIE. ld/ PR ld/21782 * testsuite/ld-x86-64/pie3.d: Expect linker error. --- bfd/elf64-x86-64.c | 7 +++++-- ld/testsuite/ld-x86-64/pie3.d | 11 +---------- 2 files changed, 6 insertions(+), 12 deletions(-) diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index 4c55c5999c3..8deb62dba5c 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -3161,6 +3161,8 @@ elf_x86_64_relocate_section (bfd *output_bfd, || (no_copyreloc_p && h->def_dynamic && !(h->root.u.def.section->flags & SEC_CODE)))) + || (bfd_link_pie (info) + && h->root.type == bfd_link_hash_undefweak) || bfd_link_dll (info))) { bool fail = false; @@ -3174,8 +3176,9 @@ elf_x86_64_relocate_section (bfd *output_bfd, { /* We can only use PC-relative relocations in PIE from non-code sections. */ - if (h->type == STT_FUNC - && (sec->flags & SEC_CODE) != 0) + if (h->root.type == bfd_link_hash_undefweak + || (h->type == STT_FUNC + && (sec->flags & SEC_CODE) != 0)) fail = true; } else if (no_copyreloc_p || bfd_link_dll (info)) diff --git a/ld/testsuite/ld-x86-64/pie3.d b/ld/testsuite/ld-x86-64/pie3.d index b943837bf64..a20029c63ba 100644 --- a/ld/testsuite/ld-x86-64/pie3.d +++ b/ld/testsuite/ld-x86-64/pie3.d @@ -1,12 +1,3 @@ #as: --64 #ld: -pie -melf_x86_64 --hash-style=sysv -z max-page-size=0x200000 -z noseparate-code -#objdump: -dw - -.*: +file format .* - - -Disassembly of section .text: - -0+191 <_start>: - +191: 48 8d 05 68 fe ff ff lea -0x198\(%rip\),%rax # 0 <_start-0x191> -#pass +#error: .*relocation R_X86_64_PC32 against undefined symbol `foo' can not be used when making a PIE object; recompile with -fPIE -- 2.30.2