* elf.c
* - ELF32/ELF64 relocation
*/
-#define DEBUG 0
+#ifndef DEBUG // This code is #include'd from the kernel, so DEBUG may already be defined
+# define DEBUG 0
+#endif
+
+#ifndef PAGE_SIZE
+# define PAGE_SIZE 4096
+#endif
#include "common.h"
#include <stdint.h>
# define DEBUGS(...)
#endif
-//#if BITS > 32
+#ifndef DISABLE_ELF64
# define SUPPORT_ELF64
-//#endif
+#endif
// === CONSTANTS ===
#if DEBUG
int ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
void *Elf32Relocate(void *Base, char **envp, const char *Filename);
int Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
+ int elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
+ int elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
+ int elf_doRelocate_unk(uint32_t , uint32_t *, Elf32_Addr , int , int , const char *, intptr_t);
#ifdef SUPPORT_ELF64
void *Elf64Relocate(void *Base, char **envp, const char *Filename);
int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
}
}
-void elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
+int elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type,
+ int bRela, const char *Sym, intptr_t iBaseDiff)
{
- intptr_t val;
+ void *symval;
switch( type )
{
// Standard 32 Bit Relocation (S+A)
case R_386_32:
- val = (intptr_t) GetSymbol(Sym, NULL);
- DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
- ptr, val, Sym);
- *ptr = val + addend;
+ if( !GetSymbol(Sym, &symval, NULL) )
+ return 1;
+ DEBUGS(" elf_doRelocate: R_386_32 *0x%x += %p('%s')",
+ ptr, symval, Sym);
+ *ptr = (intptr_t)symval + addend;
break;
// 32 Bit Relocation wrt. Offset (S+A-P)
case R_386_PC32:
DEBUGS(" elf_doRelocate: '%s'", Sym);
- val = (intptr_t) GetSymbol(Sym, NULL);
- DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
- ptr, *ptr, val, (intptr_t)ptr );
- *ptr = val + addend - (intptr_t)ptr;
+ if( !GetSymbol(Sym, &symval, NULL) ) return 1;
+ DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%p - 0x%x",
+ ptr, *ptr, symval, (intptr_t)ptr );
+ *ptr = (intptr_t)symval + addend - (intptr_t)ptr;
//*ptr = val + addend - ((Uint)ptr - iBaseDiff);
break;
case R_386_GLOB_DAT:
case R_386_JMP_SLOT:
DEBUGS(" elf_doRelocate: '%s'", Sym);
- val = (intptr_t) GetSymbol( Sym, NULL );
- DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
- *ptr = val;
+ if( !GetSymbol(Sym, &symval, NULL) ) return 1;
+ DEBUGS(" elf_doRelocate: %s *0x%x = %p", csaR_NAMES[type], ptr, symval);
+ *ptr = (intptr_t)symval;
break;
// Base Address (B+A)
case R_386_COPY: {
size_t size;
- void *src = GetSymbol(Sym, &size);
- DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, src, size);
- memcpy(ptr, src, size);
+ if( !GetSymbol(Sym, &symval, &size) ) return 1;
+ DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, symval, size);
+ memcpy(ptr, symval, size);
break; }
default:
SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
- break;
+ return 2;
}
+ return 0;
}
-void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
+int elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
{
uint32_t val;
switch(type)
// (S + A) | T
case R_ARM_ABS32:
DEBUGS(" elf_doRelocate_arm: R_ARM_ABS32 %p (%s + %x)", ptr, Sym, addend);
- val = (intptr_t)GetSymbol(Sym, NULL);
+ if( !GetSymbol(Sym, (void**)&val, NULL) ) return 1;
*ptr = val + addend;
break;
case R_ARM_GLOB_DAT:
DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
- val = (intptr_t)GetSymbol(Sym, NULL);
+ if( !GetSymbol(Sym, (void**)&val, NULL) ) return 1;
*ptr = val + addend;
break;
case R_ARM_JUMP_SLOT:
if(!bRela) addend = 0;
DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
- val = (intptr_t)GetSymbol(Sym, NULL);
+ if( !GetSymbol(Sym, (void**)&val, NULL) ) return 1;
*ptr = val + addend;
break;
// Copy
case R_ARM_COPY: {
size_t size;
- void *src = GetSymbol(Sym, &size);
+ void *src;
+ if( !GetSymbol(Sym, &src, &size) ) return 1;
DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size);
memcpy(ptr, src, size);
break; }
// Delta between link and runtime locations + A
case R_ARM_RELATIVE:
+ DEBUGS(" elf_doRelocate_arm: R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, iBaseDiff, addend);
if(Sym[0] != '\0') {
// TODO: Get delta for a symbol
SysDebug("elf_doRelocate_arm: TODO - Implment R_ARM_RELATIVE for symbols");
+ return 2;
}
else {
*ptr = iBaseDiff + addend;
break;
default:
SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
- break;
+ return 2;
}
+ return 0;
+}
+
+int elf_doRelocate_unk(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
+{
+ return 1;
}
void *Elf32Relocate(void *Base, char **envp, const char *Filename)
Elf32_Dyn *dynamicTab = NULL; // Dynamic Table Pointer
char *dynstrtab = NULL; // .dynamic String Table
Elf32_Sym *dynsymtab;
- void (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym, intptr_t iBaseDiff);
+ int (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym, intptr_t iBaseDiff);
DEBUGS("ElfRelocate: (Base=0x%x)", Base);
// Parse Program Header to get Dynamic Table
- phtab = Base + hdr->phoff;
+ phtab = (void*)( (uintptr_t)Base + hdr->phoff );
iSegmentCount = hdr->phentcount;
for(i=0;i<iSegmentCount;i++)
{
// Adjust "Real" Base
iBaseDiff = (intptr_t)Base - iRealBase;
-
+
// hdr->entrypoint += iBaseDiff; // Adjust Entrypoint
// Check if a PT_DYNAMIC segement was found
SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
}
-
+
+ // Allow writing to read-only segments, just in case they need to be relocated
+ // - Will be reversed at the end of the function
+ for( i = 0; i < iSegmentCount; i ++ )
+ {
+ if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
+ uintptr_t addr = phtab[i].VAddr + iBaseDiff;
+ uintptr_t end = addr + phtab[i].MemSize;
+ for( ; addr < end; addr += PAGE_SIZE )
+ _SysSetMemFlags(addr, 0, 1); // Unset RO
+ }
+ }
+
// Adjust Dynamic Table
dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
// === Get Symbol table and String Table ===
+ dynsymtab = NULL;
for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
{
switch(dynamicTab[j].d_tag)
DEBUGS(" elf_relocate: Beginning Relocation");
- void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend)
- {
- int type = ELF32_R_TYPE(r_info);
- int sym = ELF32_R_SYM(r_info);
- const char *symname = dynstrtab + dynsymtab[sym].nameOfs;
- do_relocate(r_info, ptr, addend, type, bRela, symname, iBaseDiff);
- }
+ int fail = 0;
switch(hdr->machine)
{
break;
default:
SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
+ do_relocate = elf_doRelocate_unk;
+ fail = 1;
break;
}
DEBUGS("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
+ #define _doRelocate(r_info, ptr, bRela, addend) \
+ do_relocate(r_info, ptr, addend, ELF32_R_TYPE(r_info), bRela, \
+ dynstrtab + dynsymtab[ELF32_R_SYM(r_info)].nameOfs, iBaseDiff);
+
// Parse Relocation Entries
if(rel && relSz)
{
{
//DEBUGS(" Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
ptr = (void*)(iBaseDiff + rel[i].r_offset);
- _doRelocate(rel[i].r_info, ptr, 0, *ptr);
+ fail |= _doRelocate(rel[i].r_info, ptr, 0, *ptr);
}
}
// Parse Relocation Entries
for( i = 0; i < j; i++ )
{
ptr = (void*)(iBaseDiff + rela[i].r_offset);
- _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
+ fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
}
}
for(i=0;i<j;i++)
{
ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
- _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
+ fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
}
}
else
for(i=0;i<j;i++)
{
ptr = (void*)(iRealBase + pltRela[i].r_offset);
- _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
+ fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
}
}
}
-
+
+ // Re-set readonly
+ for( i = 0; i < iSegmentCount; i ++ )
+ {
+ // If load and not writable
+ if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
+ uintptr_t addr = phtab[i].VAddr + iBaseDiff;
+ uintptr_t end = addr + phtab[i].MemSize;
+ for( ; addr < end; addr += PAGE_SIZE )
+ _SysSetMemFlags(addr, 1, 1); // Unset RO
+ }
+ }
+
+ if( fail ) {
+ DEBUGS("ElfRelocate: Failure");
+ return NULL;
+ }
+
+ #undef _doRelocate
+
DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
}
int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
{
Elf32_Ehdr *hdr = Base;
- Elf32_Sym *symtab;
+ Elf32_Sym *symtab = NULL;
int nbuckets = 0;
-// int iSymCount = 0;
- int i;
- Elf32_Word *pBuckets;
+ Elf32_Word *pBuckets = NULL;
Elf32_Word *pChains;
uint32_t iNameHash;
- const char *dynstrtab;
+ const char *dynstrtab = NULL;
uintptr_t iBaseDiff = -1;
Elf32_Phdr *phtab;
Elf32_Dyn *dynTab = NULL;
+ int i;
// Locate the tables
- phtab = (void*)( Base + hdr->phoff );
+ phtab = (void*)( (uintptr_t)Base + hdr->phoff );
for( i = 0; i < hdr->phentcount; i ++ )
{
if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
}
}
+ if( !symtab ) {
+ SysDebug("ERRO - No DT_SYMTAB in %p", Base);
+ return 0;
+ }
+ if( !pBuckets ) {
+ SysDebug("ERRO - No DT_HASH in %p", Base);
+ return 0;
+ }
+ if( !dynstrtab ) {
+ SysDebug("ERRO - No DT_STRTAB in %p", Base);
+ return 0;
+ }
+
+ // ... ok... maybe they haven't been relocated
+ if( (uintptr_t)symtab < (uintptr_t)Base )
+ {
+ symtab = (void*)( (uintptr_t)symtab + iBaseDiff );
+ pBuckets = (void*)( (uintptr_t)pBuckets + iBaseDiff );
+ dynstrtab = (void*)( (uintptr_t)dynstrtab + iBaseDiff );
+ SysDebug("Executable not yet relocated");
+ }
+
nbuckets = pBuckets[0];
// iSymCount = pBuckets[1];
pBuckets = &pBuckets[2];
pChains = &pBuckets[ nbuckets ];
-
+
// Get hash
iNameHash = ElfHashString(Name);
iNameHash %= nbuckets;
// Walk Chain
i = pBuckets[ iNameHash ];
if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
- *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
+ *ret = (void*)( (uintptr_t) symtab[ i ].value + iBaseDiff );
if(Size) *Size = symtab[i].size;
return 1;
}
{
i = pChains[i];
if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
- *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
+ *ret = (void*)( (uintptr_t)symtab[ i ].value + iBaseDiff );
if(Size) *Size = symtab[i].size;
return 1;
}
}
#ifdef SUPPORT_ELF64
+typedef int (*t_elf64_doreloc)(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
+
+int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
+{
+ int sym = ELF64_R_SYM(r_info);
+ int type = ELF64_R_TYPE(r_info);
+ const char *symname = strtab + symtab[sym].st_name;
+ void *symval;
+ //DEBUGS("_Elf64DoReloc: %s", symname);
+ switch( type )
+ {
+ case R_X86_64_NONE:
+ break;
+ case R_X86_64_64:
+ if( !GetSymbol(symname, &symval, NULL) ) return 1;
+ *(uint64_t*)ptr = (uintptr_t)symval + addend;
+ break;
+ case R_X86_64_COPY: {
+ size_t size;
+ if( !GetSymbol(symname, &symval, &size) ) return 1;
+ memcpy(ptr, symval, size);
+ } break;
+ case R_X86_64_GLOB_DAT:
+ if( !GetSymbol(symname, &symval, NULL) ) return 1;
+ *(uint64_t*)ptr = (uintptr_t)symval;
+ break;
+ case R_X86_64_JUMP_SLOT:
+ if( !GetSymbol(symname, &symval, NULL) ) return 1;
+ *(uint64_t*)ptr = (uintptr_t)symval;
+ break;
+ case R_X86_64_RELATIVE:
+ *(uint64_t*)ptr = (uintptr_t)Base + addend;
+ break;
+ default:
+ SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
+ return 2;
+ }
+ //DEBUGS("_Elf64DoReloc: - Good");
+ return 0;
+}
+
void *Elf64Relocate(void *Base, char **envp, const char *Filename)
{
int i;
Elf64_Ehdr *hdr = Base;
Elf64_Phdr *phtab;
- Elf64_Dyn *dyntab;
+ Elf64_Dyn *dyntab = NULL;
Elf64_Addr compiledBase = -1, baseDiff;
Elf64_Sym *symtab = NULL;
char *strtab = NULL;
DEBUGS("Elf64Relocate: e_phnum = %i", hdr->e_phnum);
// Scan for the dynamic table (and find the compiled base)
- phtab = Base + hdr->e_phoff;
+ phtab = (void*)((uintptr_t)Base + (uintptr_t)hdr->e_phoff);
for( i = 0; i < hdr->e_phnum; i ++ )
{
if(phtab[i].p_type == PT_DYNAMIC)
}
// Relocation function
- void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
- {
- int sym = ELF64_R_SYM(r_info);
- int type = ELF64_R_TYPE(r_info);
- const char *symname = strtab + symtab[sym].st_name;
- switch( type )
- {
- case R_X86_64_NONE:
- break;
- case R_X86_64_64:
- *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL) + addend;
- break;
- case R_X86_64_COPY: {
- size_t size;
- void *sym = GetSymbol(symname, &size);
- memcpy(ptr, sym, size);
- } break;
- case R_X86_64_GLOB_DAT:
- *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
- break;
- case R_X86_64_JUMP_SLOT:
- *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
- break;
- case R_X86_64_RELATIVE:
- *(uint64_t*)ptr = (uintptr_t)Base + addend;
- break;
- default:
- SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
- break;
- }
- }
+ t_elf64_doreloc fpElf64DoReloc = &_Elf64DoReloc_X86_64;
+ #define _Elf64DoReloc(info, ptr, addend) fpElf64DoReloc(Base, strtab, symtab, info, ptr, addend)
+ int fail = 0;
if( rel )
{
DEBUGS("rel_count = %i", rel_count);
for( i = 0; i < rel_count; i ++ )
{
uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
- _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
+ fail |= _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
}
}
for( i = 0; i < rela_count; i ++ )
{
uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
- _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
+ fail |= _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
}
}
for( i = 0; i < count; i ++ )
{
uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
- _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
+ fail |= _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
}
}
else {
for( i = 0; i < count; i ++ )
{
uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
- _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
+ fail |= _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
}
}
}
+ if( fail ) {
+ DEBUGS("Elf64Relocate: Failure");
+ return NULL;
+ }
+
{
void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
int j;
// Locate the tables
- phtab = (void*)( Base + hdr->e_phoff );
+ phtab = (void*)( (intptr_t)Base + (uintptr_t)hdr->e_phoff );
for( i = 0; i < hdr->e_phnum; i ++ )
{
if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
// Walk Chain
i = pBuckets[ iNameHash ];
if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
- *Ret = (void*) (intptr_t) symtab[i].st_value + iBaseDiff;
+ *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
if(Size) *Size = symtab[i].st_size;
DEBUGS("%s = %p", Name, *Ret);
return 1;
{
i = pChains[i];
if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
- *Ret = (void*)(intptr_t)symtab[i].st_value + iBaseDiff;
+ *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
if(Size) *Size = symtab[i].st_size;
DEBUGS("%s = %p", Name, *Ret);
return 1;
git.ucc.asn.au / tpg / acess2.git / blobdiff
UCC git Repository :: git.ucc.asn.au