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--- dyld/dyld-132.13/src/dyldInitialization.cpp
+++ dyld/dyld-43.1/src/dyldInitialization.cpp
@@ -1,6 +1,6 @@
/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
*
- * Copyright (c) 2004-2008 Apple Inc. All rights reserved.
+ * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
@@ -22,11 +22,8 @@
* @APPLE_LICENSE_HEADER_END@
*/
-#define __STDC_LIMIT_MACROS
-#include <stdint.h>
#include <stddef.h>
#include <string.h>
-#include <stdlib.h>
#include <mach/mach.h>
#include <mach-o/loader.h>
#include <mach-o/ldsyms.h>
@@ -34,36 +31,21 @@
#if __ppc__ || __ppc64__
#include <mach-o/ppc/reloc.h>
#endif
-#if __x86_64__
- #include <mach-o/x86_64/reloc.h>
-#endif
#include "dyld.h"
-#ifndef MH_PIE
- #define MH_PIE 0x200000
-#endif
-
-
#if __LP64__
+ #define macho_header mach_header_64
#define LC_SEGMENT_COMMAND LC_SEGMENT_64
#define macho_segment_command segment_command_64
#define macho_section section_64
#define RELOC_SIZE 3
#else
+ #define macho_header mach_header
#define LC_SEGMENT_COMMAND LC_SEGMENT
#define macho_segment_command segment_command
#define macho_section section
#define RELOC_SIZE 2
#endif
-
-#if __x86_64__
- #define POINTER_RELOC X86_64_RELOC_UNSIGNED
-#else
- #define POINTER_RELOC GENERIC_RELOC_VANILLA
-#endif
-
-// from dyld.cpp
-namespace dyld { extern bool isRosetta(); };
//
@@ -112,22 +94,20 @@
}
}
+
//
// If the kernel does not load dyld at its preferred address, we need to apply
// fixups to various initialized parts of the __DATA segment
//
static void rebaseDyld(const struct macho_header* mh, intptr_t slide)
{
- // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
- // and get interesting pointers into dyld
+ // get interesting pointers into dyld
const uint32_t cmd_count = mh->ncmds;
const struct load_command* const cmds = (struct load_command*)(((char*)mh)+sizeof(macho_header));
const struct load_command* cmd = cmds;
const struct macho_segment_command* linkEditSeg = NULL;
-#if __x86_64__
- const struct macho_segment_command* firstWritableSeg = NULL;
-#endif
const struct dysymtab_command* dynamicSymbolTable = NULL;
+ const struct macho_section* nonLazySection = NULL;
for (uint32_t i = 0; i < cmd_count; ++i) {
switch (cmd->cmd) {
case LC_SEGMENT_COMMAND:
@@ -139,19 +119,9 @@
const struct macho_section* const sectionsEnd = §ionsStart[seg->nsects];
for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
const uint8_t type = sect->flags & SECTION_TYPE;
- if ( type == S_NON_LAZY_SYMBOL_POINTERS ) {
- // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
- const uint32_t pointerCount = sect->size / sizeof(uintptr_t);
- uintptr_t* const symbolPointers = (uintptr_t*)(sect->addr + slide);
- for (uint32_t j=0; j < pointerCount; ++j) {
- symbolPointers[j] += slide;
- }
- }
+ if ( type == S_NON_LAZY_SYMBOL_POINTERS )
+ nonLazySection = sect;
}
-#if __x86_64__
- if ( (firstWritableSeg == NULL) && (seg->initprot & VM_PROT_WRITE) )
- firstWritableSeg = seg;
-#endif
}
break;
case LC_DYSYMTAB:
@@ -162,29 +132,50 @@
}
// use reloc's to rebase all random data pointers
-#if __x86_64__
- const uintptr_t relocBase = firstWritableSeg->vmaddr + slide;
-#else
const uintptr_t relocBase = (uintptr_t)mh;
-#endif
const relocation_info* const relocsStart = (struct relocation_info*)(linkEditSeg->vmaddr + slide + dynamicSymbolTable->locreloff - linkEditSeg->fileoff);
const relocation_info* const relocsEnd = &relocsStart[dynamicSymbolTable->nlocrel];
for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
- #if __ppc__ || __ppc64__ || __i36__
- if ( (reloc->r_address & R_SCATTERED) != 0 )
- throw "scattered relocation in dyld";
- #endif
- if ( reloc->r_length != RELOC_SIZE )
- throw "relocation in dyld has wrong size";
-
- if ( reloc->r_type != POINTER_RELOC )
- throw "relocation in dyld has wrong type";
-
- // update pointer by amount dyld slid
- *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
- }
-}
-
+ if ( (reloc->r_address & R_SCATTERED) == 0 ) {
+ if (reloc->r_length == RELOC_SIZE) {
+ switch(reloc->r_type) {
+ case GENERIC_RELOC_VANILLA:
+ *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
+ break;
+ }
+ }
+ }
+ else {
+ const struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
+ if (sreloc->r_length == RELOC_SIZE) {
+ uintptr_t* locationToFix = (uintptr_t*)(sreloc->r_address + relocBase);
+ switch(sreloc->r_type) {
+ case GENERIC_RELOC_VANILLA:
+ #if __ppc__ || __ppc64__
+ case PPC_RELOC_PB_LA_PTR:
+ #elif __i386__
+ case GENERIC_RELOC_PB_LA_PTR:
+ #endif
+ // Note the use of PB_LA_PTR is unique here. Seems like ld should strip out all lazy pointers
+ // but it does not. But, since all lazy-pointers point within dyld, they can be slid too
+ *locationToFix += slide;
+ break;
+ }
+ }
+ }
+ }
+
+ // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
+ if ( nonLazySection != NULL ) {
+ const uint32_t pointerCount = nonLazySection->size / sizeof(uintptr_t);
+ uintptr_t* const symbolPointers = (uintptr_t*)(nonLazySection->addr + slide);
+ for (uint32_t j=0; j < pointerCount; ++j) {
+ symbolPointers[j] += slide;
+ }
+ }
+
+
+}
//
// For some reason the kernel loads dyld with __TEXT and __LINKEDIT writable
@@ -204,7 +195,7 @@
vm_size_t size = seg->vmsize;
const bool setCurrentPermissions = false;
vm_protect(mach_task_self(), addr, size, setCurrentPermissions, seg->initprot);
- //dyld::log("dyld: segment %s, 0x%08X -> 0x%08X, set to %d\n", seg->segname, addr, addr+size-1, seg->initprot);
+ //fprintf(stderr, "dyld: segment %s, 0x%08X -> 0x%08X, set to %d\n", seg->segname, addr, addr+size-1, seg->initprot);
}
break;
}
@@ -212,130 +203,15 @@
}
}
-
-
-//
-// re-map the main executable to a new random address
-//
-static const struct macho_header* randomizeExecutableLoadAddress(const struct macho_header* orgMH, const char* envp[], uintptr_t* appsSlide)
-{
-#if __ppc__
- // don't slide PIE programs running under rosetta
- if ( dyld::isRosetta() )
- return orgMH;
-#endif
- // environment variable DYLD_NO_PIE can disable PIE
- for(const char** p = envp; *p != NULL; p++) {
- if ( strncmp(*p, "DYLD_NO_PIE=", 12) == 0 )
- return orgMH;
- }
-
- // count segments
- uint32_t segCount = 0;
- const uint32_t cmd_count = orgMH->ncmds;
- const struct load_command* const cmds = (struct load_command*)(((char*)orgMH)+sizeof(macho_header));
- const struct load_command* cmd = cmds;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
- const struct macho_segment_command* segCmd = (struct macho_segment_command*)cmd;
- // page-zero and custom stacks don't move
- if ( (strcmp(segCmd->segname, "__PAGEZERO") != 0) && (strcmp(segCmd->segname, "__UNIXSTACK") != 0) )
- ++segCount;
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
-
- // make copy of segment info
- macho_segment_command segs[segCount];
- uint32_t index = 0;
- uintptr_t highestAddressUsed = 0;
- uintptr_t lowestAddressUsed = UINTPTR_MAX;
- cmd = cmds;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
- const struct macho_segment_command* segCmd = (struct macho_segment_command*)cmd;
- if ( (strcmp(segCmd->segname, "__PAGEZERO") != 0) && (strcmp(segCmd->segname, "__UNIXSTACK") != 0) ) {
- segs[index++] = *segCmd;
- if ( (segCmd->vmaddr + segCmd->vmsize) > highestAddressUsed )
- highestAddressUsed = ((segCmd->vmaddr + segCmd->vmsize) + 4095) & -4096;
- if ( segCmd->vmaddr < lowestAddressUsed )
- lowestAddressUsed = segCmd->vmaddr;
- // do nothing if kernel has already randomized load address
- if ( (strcmp(segCmd->segname, "__TEXT") == 0) && (segCmd->vmaddr != (uintptr_t)orgMH) )
- return orgMH;
- }
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
-
- // choose a random new base address
-#if __LP64__
- uintptr_t highestAddressPossible = highestAddressUsed + 0x100000000ULL;
-#elif __arm__
- uintptr_t highestAddressPossible = 0x2fe00000;
-#else
- uintptr_t highestAddressPossible = 0x80000000;
-#endif
- uintptr_t sizeNeeded = highestAddressUsed-lowestAddressUsed;
- if ( (highestAddressPossible-sizeNeeded) < highestAddressUsed ) {
- // new and old segments will overlap
- // need better algorithm for remapping
- // punt and don't re-map
- return orgMH;
- }
- uintptr_t possibleRange = (highestAddressPossible-sizeNeeded) - highestAddressUsed;
- uintptr_t newBaseAddress = highestAddressUsed + ((arc4random() % possibleRange) & -4096);
-
- vm_address_t addr = newBaseAddress;
- // reserve new address range
- if ( vm_allocate(mach_task_self(), &addr, sizeNeeded, VM_FLAGS_FIXED) == KERN_SUCCESS ) {
- // copy each segment to new address
- for (uint32_t i = 0; i < segCount; ++i) {
- uintptr_t newSegAddress = segs[i].vmaddr - lowestAddressUsed + newBaseAddress;
- if ( (vm_copy(mach_task_self(), segs[i].vmaddr, segs[i].vmsize, newSegAddress) != KERN_SUCCESS)
- #if !__arm__ // work around for <rdar://problem/5736393>
- || (vm_protect(mach_task_self(), newSegAddress, segs[i].vmsize, true, segs[i].maxprot) != KERN_SUCCESS)
- #endif
- || (vm_protect(mach_task_self(), newSegAddress, segs[i].vmsize, false, segs[i].initprot) != KERN_SUCCESS) ) {
- // can't copy so dealloc new region and run with original base address
- vm_deallocate(mach_task_self(), newBaseAddress, sizeNeeded);
- dyld::warn("could not relocate position independent executable\n");
- return orgMH;
- }
- }
- // unmap original segments
- vm_deallocate(mach_task_self(), lowestAddressUsed, highestAddressUsed-lowestAddressUsed);
-
- // run with newly mapped executable
- *appsSlide = newBaseAddress - lowestAddressUsed;
- return (const struct macho_header*)newBaseAddress;
- }
-
- // can't get new range, so don't slide to random address
- return orgMH;
-}
-
extern "C" void dyld_exceptions_init(const struct macho_header*, uintptr_t slide); // in dyldExceptions.cpp
extern "C" void mach_init();
//
-// _pthread_keys is partitioned in a lower part that dyld will use; libSystem
-// will use the upper part. We set __pthread_tsd_first to 1 as the start of
-// the lower part. Libc will take #1 and c++ exceptions will take #2. There
-// is one free key=3 left.
-//
-extern "C" {
- extern int __pthread_tsd_first;
- extern void _pthread_keys_init();
-}
-
-
-//
// This is code to bootstrap dyld. This work in normally done for a program by dyld and crt.
// In dyld we have to do this manually.
//
-uintptr_t start(const struct macho_header* appsMachHeader, int argc, const char* argv[], intptr_t slide)
+uintptr_t start(const struct mach_header* appsMachHeader, int argc, const char* argv[], intptr_t slide)
{
// _mh_dylinker_header is magic symbol defined by static linker (ld), see <mach-o/ldsyms.h>
const struct macho_header* dyldsMachHeader = (const struct macho_header*)(((char*)&_mh_dylinker_header)+slide);
@@ -346,8 +222,6 @@
rebaseDyld(dyldsMachHeader, slide);
}
- uintptr_t appsSlide = 0;
-
// enable C++ exceptions to work inside dyld
dyld_exceptions_init(dyldsMachHeader, slide);
@@ -368,12 +242,8 @@
// run all C++ initializers inside dyld
runDyldInitializers(dyldsMachHeader, slide, argc, argv, envp, apple);
- // if main executable was linked -pie, then randomize its load address
- if ( appsMachHeader->flags & MH_PIE )
- appsMachHeader = randomizeExecutableLoadAddress(appsMachHeader, envp, &appsSlide);
-
// now that we are done bootstrapping dyld, call dyld's main
- return dyld::_main(appsMachHeader, appsSlide, argc, argv, envp, apple);
+ return dyld::_main(appsMachHeader, argc, argv, envp, apple);
}