c0eb4aa41b
Prior to this change the loader self relocation code interpreted amd64's rela relocations as if they were rel relocations, discarding the addend. This "works" because GNU ld 2.17.50 stores the addend value in both the r_addend field of the relocation (as expected) and at the target of the relocation. Other linkers, and possibly other versions of GNU ld, won't have this behaviour, so interpret the relocations correctly. Reported by: George Rimar Reviewed by: andrew MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D8681
125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/*-
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* Copyright (c) 2008-2010 Rui Paulo <rpaulo@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <elf.h>
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#include <bootstrap.h>
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#if defined(__aarch64__) || defined(__amd64__)
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#define ElfW_Rel Elf64_Rela
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#define ElfW_Dyn Elf64_Dyn
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#define ELFW_R_TYPE ELF64_R_TYPE
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#define ELF_RELA
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#elif defined(__arm__) || defined(__i386__)
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#define ElfW_Rel Elf32_Rel
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#define ElfW_Dyn Elf32_Dyn
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#define ELFW_R_TYPE ELF32_R_TYPE
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#else
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#error architecture not supported
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#endif
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#if defined(__aarch64__)
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#define RELOC_TYPE_NONE R_AARCH64_NONE
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#define RELOC_TYPE_RELATIVE R_AARCH64_RELATIVE
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#elif defined(__amd64__)
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#define RELOC_TYPE_NONE R_X86_64_NONE
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#define RELOC_TYPE_RELATIVE R_X86_64_RELATIVE
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#elif defined(__arm__)
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#define RELOC_TYPE_NONE R_ARM_NONE
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#define RELOC_TYPE_RELATIVE R_ARM_RELATIVE
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#elif defined(__i386__)
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#define RELOC_TYPE_NONE R_386_NONE
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#define RELOC_TYPE_RELATIVE R_386_RELATIVE
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#endif
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void self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic);
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/*
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* A simple elf relocator.
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*/
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void
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self_reloc(Elf_Addr baseaddr, ElfW_Dyn *dynamic)
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{
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Elf_Word relsz, relent;
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Elf_Addr *newaddr;
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ElfW_Rel *rel;
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ElfW_Dyn *dynp;
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/*
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* Find the relocation address, its size and the relocation entry.
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*/
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relsz = 0;
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relent = 0;
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for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) {
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switch (dynp->d_tag) {
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case DT_REL:
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case DT_RELA:
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rel = (ElfW_Rel *)(dynp->d_un.d_ptr + baseaddr);
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break;
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case DT_RELSZ:
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case DT_RELASZ:
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relsz = dynp->d_un.d_val;
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break;
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case DT_RELENT:
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case DT_RELAENT:
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relent = dynp->d_un.d_val;
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break;
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default:
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break;
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}
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}
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/*
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* Perform the actual relocation. We rely on the object having been
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* linked at 0, so that the difference between the load and link
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* address is the same as the load address.
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*/
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for (; relsz > 0; relsz -= relent) {
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switch (ELFW_R_TYPE(rel->r_info)) {
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case RELOC_TYPE_NONE:
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/* No relocation needs be performed. */
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break;
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case RELOC_TYPE_RELATIVE:
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newaddr = (Elf_Addr *)(rel->r_offset + baseaddr);
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#ifdef ELF_RELA
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/* Addend relative to the base address. */
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*newaddr = baseaddr + rel->r_addend;
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#else
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/* Address relative to the base address. */
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*newaddr += baseaddr;
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#endif
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break;
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default:
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/* XXX: do we need other relocations ? */
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break;
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}
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rel = (ElfW_Rel *)(void *)((caddr_t) rel + relent);
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}
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}
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