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--- dyld/dyld-750.6/src/dyldInitialization.cpp
+++ dyld/dyld-640.2/src/dyldInitialization.cpp
@@ -27,35 +27,76 @@
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
-#include <sys/mman.h>
+#include <Availability.h>
#include <mach/mach.h>
-
-#include "dyld2.h"
+#include <mach-o/loader.h>
+#include <mach-o/ldsyms.h>
+#include <mach-o/reloc.h>
+#if __x86_64__
+ #include <mach-o/x86_64/reloc.h>
+#endif
+#include "dyld.h"
#include "dyldSyscallInterface.h"
-#include "MachOAnalyzer.h"
-#include "Tracing.h"
-
-// from libc.a
-extern "C" void mach_init();
-extern "C" void __guard_setup(const char* apple[]);
-
-
-// from dyld_debugger.cpp
+
+// from dyld_gdb.cpp
+extern void addImagesToAllImages(uint32_t infoCount, const dyld_image_info info[]);
extern void syncProcessInfo();
-const dyld::SyscallHelpers* gSyscallHelpers = NULL;
-
-
-//
-// Code to bootstrap dyld into a runnable state
-//
-//
-
-namespace dyldbootstrap {
-
+#ifndef MH_PIE
+ #define MH_PIE 0x200000
+#endif
// currently dyld has no initializers, but if some come back, set this to non-zero
#define DYLD_INITIALIZER_SUPPORT 0
+
+#if __LP64__
+ #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 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
+
+#ifndef BIND_OPCODE_THREADED
+#define BIND_OPCODE_THREADED 0xD0
+#endif
+
+#ifndef BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB
+#define BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB 0x00
+#endif
+
+#ifndef BIND_SUBOPCODE_THREADED_APPLY
+#define BIND_SUBOPCODE_THREADED_APPLY 0x01
+#endif
+
+
+#if __has_feature(ptrauth_calls)
+#include <ptrauth.h>
+#endif
+
+
+#if TARGET_IPHONE_SIMULATOR
+const dyld::SyscallHelpers* gSyscallHelpers = NULL;
+#endif
+
+
+//
+// Code to bootstrap dyld into a runnable state
+//
+//
+
+namespace dyldbootstrap {
+
#if DYLD_INITIALIZER_SUPPORT
@@ -71,7 +112,7 @@
// dyld (should be static) but is a dynamic executable and needs this hack to run its own initializers.
// We pass argc, argv, etc in case libc.a uses those arguments
//
-static void runDyldInitializers(int argc, const char* argv[], const char* envp[], const char* apple[])
+static void runDyldInitializers(const struct macho_header* mh, intptr_t slide, int argc, const char* argv[], const char* envp[], const char* apple[])
{
for (const Initializer* p = &inits_start; p < &inits_end; ++p) {
(*p)(argc, argv, envp, apple);
@@ -81,48 +122,366 @@
//
-// On disk, all pointers in dyld's DATA segment are chained together.
-// They need to be fixed up to be real pointers to run.
-//
-static void rebaseDyld(const dyld3::MachOLoaded* dyldMH)
+// The kernel may have slid a Position Independent Executable
+//
+static uintptr_t slideOfMainExecutable(const struct macho_header* mh)
{
- // walk all fixups chains and rebase dyld
- const dyld3::MachOAnalyzer* ma = (dyld3::MachOAnalyzer*)dyldMH;
- assert(ma->hasChainedFixups());
- uintptr_t slide = (long)ma; // all fixup chain based images have a base address of zero, so slide == load address
- __block Diagnostics diag;
- ma->withChainStarts(diag, 0, ^(const dyld_chained_starts_in_image* starts) {
- ma->fixupAllChainedFixups(diag, starts, slide, dyld3::Array<const void*>(), nullptr);
- });
- diag.assertNoError();
-
- // now that rebasing done, initialize mach/syscall layer
- mach_init();
-
- // <rdar://47805386> mark __DATA_CONST segment in dyld as read-only (once fixups are done)
- ma->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& info, bool& stop) {
- if ( info.readOnlyData ) {
- ::mprotect(((uint8_t*)(dyldMH))+info.vmAddr, (size_t)info.vmSize, VM_PROT_READ);
+ 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;
+ 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 ( (segCmd->fileoff == 0) && (segCmd->filesize != 0)) {
+ return (uintptr_t)mh - segCmd->vmaddr;
+ }
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+ return 0;
+}
+
+inline uint64_t read_uleb128(const uint8_t*& p, const uint8_t* end) {
+ uint64_t result = 0;
+ int bit = 0;
+ do {
+ if (p == end)
+ throw "malformed uleb128 extends beyond trie";
+ uint64_t slice = *p & 0x7f;
+
+ if (bit >= 64 || slice << bit >> bit != slice)
+ throw "uleb128 too big for 64-bits";
+ else {
+ result |= (slice << bit);
+ bit += 7;
}
- });
-}
-
+ }
+ while (*p++ & 0x80);
+ return result;
+}
+
+inline int64_t read_sleb128(const uint8_t*& p, const uint8_t* end)
+{
+ int64_t result = 0;
+ int bit = 0;
+ uint8_t byte;
+ do {
+ if (p == end)
+ throw "malformed sleb128";
+ byte = *p++;
+ result |= (((int64_t)(byte & 0x7f)) << bit);
+ bit += 7;
+ } while (byte & 0x80);
+ // sign extend negative numbers
+ if ( (byte & 0x40) != 0 )
+ result |= (~0ULL) << bit;
+ return result;
+}
+
+
+//
+// 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
+ 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;
+
+ // First look for compressed info and use it if it exists.
+ const struct macho_segment_command* linkEditSeg = NULL;
+ const dyld_info_command* dyldInfoCmd = NULL;
+ for (uint32_t i = 0; i < cmd_count; ++i) {
+ switch (cmd->cmd) {
+ case LC_SEGMENT_COMMAND:
+ {
+ const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+ if ( strcmp(seg->segname, "__LINKEDIT") == 0 )
+ linkEditSeg = seg;
+ break;
+ }
+ case LC_DYLD_INFO_ONLY:
+ dyldInfoCmd = (struct dyld_info_command*)cmd;
+ break;
+ }
+ if (dyldInfoCmd && linkEditSeg)
+ break;
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+ if ( linkEditSeg == NULL )
+ throw "dyld missing LINKEDIT";
+
+ // Reset the iterator.
+ cmd = cmds;
+
+ auto getSegmentAtIndex = [cmd_count, cmds](unsigned segIndex) -> const struct macho_segment_command* {
+ const struct load_command* cmd = cmds;
+ for (uint32_t i = 0; i < cmd_count; ++i) {
+ switch (cmd->cmd) {
+ case LC_SEGMENT_COMMAND:
+ if (!segIndex) {
+ const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+ return seg;
+ }
+ --segIndex;
+ break;
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+ throw "out of bounds command";
+ return 0;
+ };
+
+ auto segActualLoadAddress = [&](unsigned segIndex) -> uintptr_t {
+ const struct macho_segment_command* seg = getSegmentAtIndex(segIndex);
+ return seg->vmaddr + slide;
+ };
+
+#if __has_feature(ptrauth_calls)
+ auto imageBaseAddress = [cmds, cmd_count]() -> uintptr_t {
+ const struct load_command* cmd = cmds;
+ for (uint32_t i = 0; i < cmd_count; ++i) {
+ switch (cmd->cmd) {
+ case LC_SEGMENT_COMMAND: {
+ const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+ if ( (seg->fileoff == 0) && (seg->filesize != 0) )
+ return seg->vmaddr;
+ break;
+ }
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+ return 0;
+ };
+#endif
+
+ if (dyldInfoCmd && (dyldInfoCmd->bind_size != 0) ) {
+ if ( dyldInfoCmd->rebase_size != 0 )
+ throw "unthreaded rebases are not supported";
+
+ const uint8_t* linkEditBase = (uint8_t*)(linkEditSeg->vmaddr + slide - linkEditSeg->fileoff);
+
+ const uint8_t* const start = linkEditBase + dyldInfoCmd->bind_off;
+ const uint8_t* const end = &start[dyldInfoCmd->bind_size];
+ const uint8_t* p = start;
+
+ uintptr_t segmentStartAddress = 0;
+ uint64_t segOffset = 0;
+ int segIndex = 0;
+#if __has_feature(ptrauth_calls)
+ uintptr_t fBaseAddress = imageBaseAddress();
+#endif
+ bool done = false;
+
+ while ( !done && (p < end) ) {
+ uint8_t immediate = *p & BIND_IMMEDIATE_MASK;
+ uint8_t opcode = *p & BIND_OPCODE_MASK;
+ ++p;
+ switch (opcode) {
+ case BIND_OPCODE_DONE:
+ done = true;
+ break;
+ case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
+ break;
+ case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
+ break;
+ case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
+ break;
+ case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
+ while (*p != '\0')
+ ++p;
+ ++p;
+ break;
+ case BIND_OPCODE_SET_TYPE_IMM:
+ break;
+ case BIND_OPCODE_SET_ADDEND_SLEB:
+ read_sleb128(p, end);
+ break;
+ case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
+ segIndex = immediate;
+ segmentStartAddress = segActualLoadAddress(segIndex);
+ segOffset = read_uleb128(p, end);
+ break;
+ case BIND_OPCODE_ADD_ADDR_ULEB:
+ segOffset += read_uleb128(p, end);
+ break;
+ case BIND_OPCODE_DO_BIND:
+ break;
+ case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
+ break;
+ case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
+ break;
+ case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
+ read_uleb128(p, end);
+ read_uleb128(p, end);
+ break;
+ case BIND_OPCODE_THREADED:
+ // Note the immediate is a sub opcode
+ switch (immediate) {
+ case BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB:
+ read_uleb128(p, end);
+ break;
+ case BIND_SUBOPCODE_THREADED_APPLY: {
+ uint64_t delta = 0;
+ do {
+ uintptr_t address = segmentStartAddress + (uintptr_t)segOffset;
+ uint64_t value = *(uint64_t*)address;
+
+#if __has_feature(ptrauth_calls)
+ uint16_t diversity = (uint16_t)(value >> 32);
+ bool hasAddressDiversity = (value & (1ULL << 48)) != 0;
+ ptrauth_key key = (ptrauth_key)((value >> 49) & 0x3);
+ bool isAuthenticated = (value & (1ULL << 63)) != 0;
+#endif
+ bool isRebase = (value & (1ULL << 62)) == 0;
+ if (isRebase) {
+
+#if __has_feature(ptrauth_calls)
+ if (isAuthenticated) {
+ // The new value for a rebase is the low 32-bits of the threaded value plus the slide.
+ uint64_t newValue = (value & 0xFFFFFFFF) + slide;
+ // Add in the offset from the mach_header
+ newValue += fBaseAddress;
+ // We have bits to merge in to the discriminator
+ uintptr_t discriminator = diversity;
+ if (hasAddressDiversity) {
+ // First calculate a new discriminator using the address of where we are trying to store the value
+ discriminator = __builtin_ptrauth_blend_discriminator((void*)address, discriminator);
+ }
+ switch (key) {
+ case ptrauth_key_asia:
+ newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asia, discriminator);
+ break;
+ case ptrauth_key_asib:
+ newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asib, discriminator);
+ break;
+ case ptrauth_key_asda:
+ newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asda, discriminator);
+ break;
+ case ptrauth_key_asdb:
+ newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asdb, discriminator);
+ break;
+ }
+ *(uint64_t*)address = newValue;
+ } else
+#endif
+ {
+ // Regular pointer which needs to fit in 51-bits of value.
+ // C++ RTTI uses the top bit, so we'll allow the whole top-byte
+ // and the signed-extended bottom 43-bits to be fit in to 51-bits.
+ uint64_t top8Bits = value & 0x0007F80000000000ULL;
+ uint64_t bottom43Bits = value & 0x000007FFFFFFFFFFULL;
+ uint64_t targetValue = ( top8Bits << 13 ) | (((intptr_t)(bottom43Bits << 21) >> 21) & 0x00FFFFFFFFFFFFFF);
+ targetValue = targetValue + slide;
+ *(uint64_t*)address = targetValue;
+ }
+ }
+
+ // The delta is bits [51..61]
+ // And bit 62 is to tell us if we are a rebase (0) or bind (1)
+ value &= ~(1ULL << 62);
+ delta = ( value & 0x3FF8000000000000 ) >> 51;
+ segOffset += delta * sizeof(uintptr_t);
+ } while ( delta != 0 );
+ break;
+ }
+ default:
+ throw "unknown threaded bind subopcode";
+ }
+ break;
+ default:
+ throw "unknown bind opcode";
+ }
+ }
+ return;
+ }
+
+#if __x86_64__
+ const struct macho_segment_command* firstWritableSeg = NULL;
+#endif
+ const struct dysymtab_command* dynamicSymbolTable = NULL;
+ for (uint32_t i = 0; i < cmd_count; ++i) {
+ switch (cmd->cmd) {
+ case LC_SEGMENT_COMMAND:
+ {
+ const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+ const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
+ 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 = (uint32_t)(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 __x86_64__
+ if ( (firstWritableSeg == NULL) && (seg->initprot & VM_PROT_WRITE) )
+ firstWritableSeg = seg;
+#endif
+ }
+ break;
+ case LC_DYSYMTAB:
+ dynamicSymbolTable = (struct dysymtab_command *)cmd;
+ break;
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+
+ // use reloc's to rebase all random data pointers
+#if __x86_64__
+ if ( firstWritableSeg == NULL )
+ throw "no writable segment in dyld";
+ 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 ( 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;
+ }
+}
+
+
+extern "C" void mach_init();
+extern "C" void __guard_setup(const char* apple[]);
//
// 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 dyld3::MachOLoaded* appsMachHeader, int argc, const char* argv[],
- const dyld3::MachOLoaded* dyldsMachHeader, uintptr_t* startGlue)
+uintptr_t start(const struct macho_header* appsMachHeader, int argc, const char* argv[],
+ intptr_t slide, const struct macho_header* dyldsMachHeader,
+ uintptr_t* startGlue)
{
-
- // Emit kdebug tracepoint to indicate dyld bootstrap has started <rdar://46878536>
- dyld3::kdebug_trace_dyld_marker(DBG_DYLD_TIMING_BOOTSTRAP_START, 0, 0, 0, 0);
-
// if kernel had to slide dyld, we need to fix up load sensitive locations
// we have to do this before using any global variables
- rebaseDyld(dyldsMachHeader);
+ slide = slideOfMainExecutable(dyldsMachHeader);
+ bool shouldRebase = slide != 0;
+#if __has_feature(ptrauth_calls)
+ shouldRebase = true;
+#endif
+ if ( shouldRebase ) {
+ rebaseDyld(dyldsMachHeader, slide);
+ }
+
+ // allow dyld to use mach messaging
+ mach_init();
// kernel sets up env pointer to be just past end of agv array
const char** envp = &argv[argc+1];
@@ -137,31 +496,37 @@
#if DYLD_INITIALIZER_SUPPORT
// run all C++ initializers inside dyld
- runDyldInitializers(argc, argv, envp, apple);
+ runDyldInitializers(dyldsMachHeader, slide, argc, argv, envp, apple);
#endif
// now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = appsMachHeader->getSlide();
- return dyld::_main((macho_header*)appsMachHeader, appsSlide, argc, argv, envp, apple, startGlue);
-}
-
-
-#if TARGET_OS_SIMULATOR
+ uintptr_t appsSlide = slideOfMainExecutable(appsMachHeader);
+ return dyld::_main(appsMachHeader, appsSlide, argc, argv, envp, apple, startGlue);
+}
+
+
+#if TARGET_IPHONE_SIMULATOR
extern "C" uintptr_t start_sim(int argc, const char* argv[], const char* envp[], const char* apple[],
- const dyld3::MachOLoaded* mainExecutableMH, const dyld3::MachOLoaded* dyldMH, uintptr_t dyldSlide,
+ const macho_header* mainExecutableMH, const macho_header* dyldMH, uintptr_t dyldSlide,
const dyld::SyscallHelpers*, uintptr_t* startGlue);
-
+
uintptr_t start_sim(int argc, const char* argv[], const char* envp[], const char* apple[],
- const dyld3::MachOLoaded* mainExecutableMH, const dyld3::MachOLoaded* dyldSimMH, uintptr_t dyldSlide,
+ const macho_header* mainExecutableMH, const macho_header* dyldMH, uintptr_t dyldSlide,
const dyld::SyscallHelpers* sc, uintptr_t* startGlue)
{
- // save table of syscall pointers
- gSyscallHelpers = sc;
-
- // dyld_sim uses chained rebases, so it always need to be fixed up
- rebaseDyld(dyldSimMH);
+ // if simulator dyld loaded slid, it needs to rebase itself
+ // we have to do this before using any global variables
+ if ( dyldSlide != 0 ) {
+ rebaseDyld(dyldMH, dyldSlide);
+ }
+
+ // save table of syscall pointers
+ gSyscallHelpers = sc;
+
+ // allow dyld to use mach messaging
+ mach_init();
// set up random value for stack canary
__guard_setup(apple);
@@ -171,8 +536,8 @@
syncProcessInfo();
// now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = mainExecutableMH->getSlide();
- return dyld::_main((macho_header*)mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
+ uintptr_t appsSlide = slideOfMainExecutable(mainExecutableMH);
+ return dyld::_main(mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
}
#endif