* 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>
+#ifndef assert
+# include <assert.h>
+#endif
#include "elf32.h"
#include "elf64.h"
#if DEBUG
-# define DEBUGS(v...) SysDebug("ld-acess - " v)
+# define DEBUG_OUT(...) SysDebug(__VA_ARGS__)
#else
-# define DEBUGS(...)
+# define DEBUG_OUT(...) do{}while(0) //((void)(__VA_ARGS__))
#endif
-//#if BITS > 32
+#define WARNING(f,...) SysDebug("WARN: "f ,## __VA_ARGS__) // Malformed file
+#define NOTICE(f,...) SysDebug("NOTICE: "f ,## __VA_ARGS__) // Missing relocation
+#define TRACE(f,...) DEBUG_OUT("TRACE:%s:%i "f, __func__, __LINE__ ,## __VA_ARGS__) // Debugging trace
+
+#ifndef DISABLE_ELF64
# define SUPPORT_ELF64
-//#endif
+#endif
+
+typedef struct
+{
+ void *Base;
+ intptr_t iBaseDiff;
+ const char *strtab;
+ Elf32_Sym *symtab;
+} tElfRelocInfo;
+
+typedef int tElf32RelocFcn(tElfRelocInfo *Info, uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int bRela);
// === CONSTANTS ===
#if DEBUG
//static const char *csaDT_NAMES[] = {"DT_NULL", "DT_NEEDED", "DT_PLTRELSZ", "DT_PLTGOT", "DT_HASH", "DT_STRTAB", "DT_SYMTAB", "DT_RELA", "DT_RELASZ", "DT_RELAENT", "DT_STRSZ", "DT_SYMENT", "DT_INIT", "DT_FINI", "DT_SONAME", "DT_RPATH", "DT_SYMBOLIC", "DT_REL", "DT_RELSZ", "DT_RELENT", "DT_PLTREL", "DT_DEBUG", "DT_TEXTREL", "DT_JMPREL"};
-static const char *csaR_NAMES[] = {"R_386_NONE", "R_386_32", "R_386_PC32", "R_386_GOT32", "R_386_PLT32", "R_386_COPY", "R_386_GLOB_DAT", "R_386_JMP_SLOT", "R_386_RELATIVE", "R_386_GOTOFF", "R_386_GOTPC", "R_386_LAST"};
+//static const char *csaR_NAMES[] = {"R_386_NONE", "R_386_32", "R_386_PC32", "R_386_GOT32", "R_386_PLT32", "R_386_COPY", "R_386_GLOB_DAT", "R_386_JMP_SLOT", "R_386_RELATIVE", "R_386_GOTOFF", "R_386_GOTPC", "R_386_LAST"};
#endif
// === PROTOTYPES ===
void *ElfRelocate(void *Base, char **envp, const char *Filename);
int ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
void *Elf32Relocate(void *Base, char **envp, const char *Filename);
+ int Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff);
+ int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type);
int Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
+tElf32RelocFcn elf_doRelocate_386;
+tElf32RelocFcn elf_doRelocate_arm;
+tElf32RelocFcn elf_doRelocate_unk;
#ifdef SUPPORT_ELF64
+int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
void *Elf64Relocate(void *Base, char **envp, const char *Filename);
int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
#endif
+ int Elf32GetSymbolReloc(tElfRelocInfo *Info, const Elf32_Sym *Symbol, void **Ret, size_t *Size);
uint32_t ElfHashString(const char *name);
// === CODE ===
}
}
+int elf_doRelocate_386(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
+{
+ const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
+ void *symval = (void*)sym->st_value;
+ size_t size = sym->st_size;
+ TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
+ switch( ELF32_R_TYPE(r_info) )
+ {
+ // Standard 32 Bit Relocation (S+A)
+ case R_386_32:
+ TRACE("R_386_32 *0x%x = %p + 0x%x", ptr, symval, addend);
+ *ptr = (intptr_t)symval + addend;
+ break;
+
+ // 32 Bit Relocation wrt. Offset (S+A-P)
+ case R_386_PC32:
+ TRACE("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;
+
+ // Absolute Value of a symbol (S)
+ case R_386_GLOB_DAT:
+ TRACE("R_386_GLOB_DAT *0x%x = %p", ptr, symval); if(0)
+ case R_386_JMP_SLOT:
+ TRACE("R_386_JMP_SLOT *0x%x = %p", ptr, symval);
+ *ptr = (intptr_t)symval;
+ break;
+
+ // Base Address (B+A)
+ case R_386_RELATIVE:
+ TRACE("R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, Info->iBaseDiff, addend);
+ *ptr = Info->iBaseDiff + addend;
+ break;
+
+ case R_386_COPY: {
+ void *old_symval = symval;
+ GetSymbol(Info->strtab + sym->st_name, &symval, &size, Info->Base);
+ if( symval == old_symval )
+ {
+ if( ELF32_ST_BIND(sym->st_info) != STB_WEAK )
+ {
+ WARNING("sym={val:%p,size:0x%x,info:0x%x,other:0x%x,shndx:%i}",
+ sym->st_value, sym->st_size, sym->st_info, sym->st_other, sym->st_shndx);
+ WARNING("Can't find required external symbol '%s' for R_386_COPY", Info->strtab + sym->st_name);
+ return 1;
+ }
+ // Don't bother doing the memcpy
+ TRACE("R_386_COPY (%p, %p, %i)", ptr, symval, size);
+ }
+ else
+ {
+ TRACE("R_386_COPY (%p, %p, %i)", ptr, symval, size);
+ memcpy(ptr, symval, size);
+ }
+ break; }
+
+ default:
+ WARNING("Unknown relocation %i", ELF32_ST_TYPE(r_info));
+ return 2;
+ }
+ return 0;
+}
+
+int elf_doRelocate_arm(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
+{
+ const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
+ void *symval = (void*)sym->st_value;
+ size_t size = sym->st_size;
+ TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
+ uintptr_t val = (uintptr_t)symval;
+ switch( ELF32_R_TYPE(r_info) )
+ {
+ // (S + A) | T
+ case R_ARM_ABS32:
+ TRACE("R_ARM_ABS32 %p (%p + %x)", ptr, symval, addend);
+ *ptr = val + addend;
+ break;
+ case R_ARM_GLOB_DAT:
+ TRACE("R_ARM_GLOB_DAT %p (%p + %x)", ptr, symval, addend);
+ *ptr = val + addend;
+ break;
+ case R_ARM_JUMP_SLOT:
+ if(!bRela) addend = 0;
+ TRACE("R_ARM_JUMP_SLOT %p (%p + %x)", ptr, symval, addend);
+ *ptr = val + addend;
+ break;
+ // Copy
+ case R_ARM_COPY:
+ TRACE("R_ARM_COPY (%p, %p, %i)", ptr, symval, size);
+ memcpy(ptr, symval, size);
+ break;
+ // Delta between link and runtime locations + A
+ case R_ARM_RELATIVE:
+ TRACE("R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, Info->iBaseDiff, addend);
+ if(ELF32_R_SYM(r_info) != 0) {
+ // TODO: Get delta for a symbol
+ WARNING("TODO - Implment R_ARM_RELATIVE for symbols");
+ return 2;
+ }
+ else {
+ *ptr = Info->iBaseDiff + addend;
+ }
+ break;
+ default:
+ WARNING("Unknown Relocation, %i", ELF32_R_TYPE(r_info));
+ return 2;
+ }
+ return 0;
+}
+
+int elf_doRelocate_unk(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
+{
+ return 1;
+}
+
void *Elf32Relocate(void *Base, char **envp, const char *Filename)
{
- Elf32_Ehdr *hdr = Base;
- Elf32_Phdr *phtab;
- int i, j; // Counters
+ const Elf32_Ehdr *hdr = Base;
char *libPath;
intptr_t iRealBase = -1;
intptr_t iBaseDiff;
- int iSegmentCount;
-// int iSymCount;
Elf32_Rel *rel = NULL;
Elf32_Rela *rela = NULL;
void *plt = NULL;
int relaSz=0, relaEntSz=8;
int pltSz=0, pltType=0;
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);
- DEBUGS("ElfRelocate: (Base=0x%x)", Base);
+ TRACE("(Base=0x%x)", Base);
// Check magic header
// Parse Program Header to get Dynamic Table
- phtab = Base + hdr->phoff;
- iSegmentCount = hdr->phentcount;
- for(i=0;i<iSegmentCount;i++)
+ // - Determine the linked base of the executable
+ const Elf32_Phdr *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
+ const int iSegmentCount = hdr->phentcount;
+ for(int i = 0; i < iSegmentCount; i ++)
{
- // Determine linked base address
- if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
- iRealBase = phtab[i].VAddr;
-
- // Find Dynamic Section
- if(phtab[i].Type == PT_DYNAMIC) {
- if(dynamicTab) {
- DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
- continue;
+ switch(phtab[i].Type)
+ {
+ case PT_LOAD:
+ // Determine linked base address
+ if( iRealBase > phtab[i].VAddr)
+ iRealBase = phtab[i].VAddr;
+ break;
+ case PT_DYNAMIC:
+ // Find Dynamic Section
+ if(!dynamicTab) {
+ dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
}
- dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
- j = i; // Save Dynamic Table ID
+ else {
+ WARNING("elf_relocate: Multiple PT_DYNAMIC segments");
+ }
+ break;
}
}
// Page Align real base
iRealBase &= ~0xFFF;
- DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
+ TRACE("True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
// Adjust "Real" Base
iBaseDiff = (intptr_t)Base - iRealBase;
-
-// hdr->entrypoint += iBaseDiff; // Adjust Entrypoint
-
+
// Check if a PT_DYNAMIC segement was found
if(!dynamicTab) {
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( int 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 ===
- for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
+ char *dynstrtab = NULL; // .dynamic String Table
+ Elf32_Sym *dynsymtab = NULL;
+ Elf32_Word *hashtable = NULL;
+ int iSymCount = 0;
+ for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
{
- switch(dynamicTab[j].d_tag)
+ const Elf32_Dyn *dt = &dynamicTab[j];
+ switch(dt->d_tag)
{
// --- Symbol Table ---
case DT_SYMTAB:
- DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
- dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
- if(iBaseDiff != 0) dynamicTab[j].d_val += iBaseDiff;
- dynsymtab = (void*)(intptr_t)dynamicTab[j].d_val;
+ TRACE("DYNAMIC Symbol Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
+ dynsymtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
break;
// --- String Table ---
case DT_STRTAB:
- DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
- dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
- if(iBaseDiff != 0) dynamicTab[j].d_val += iBaseDiff;
- dynstrtab = (void*)(intptr_t)dynamicTab[j].d_val;
+ TRACE("DYNAMIC String Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
+ dynstrtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
break;
// --- Hash Table --
case DT_HASH:
- if(iBaseDiff != 0) dynamicTab[j].d_val += iBaseDiff;
-// iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
+ TRACE("DYNAMIC Hash table %p (%p)", dt->d_val, dt->d_val + iBaseDiff);
+ hashtable = (void*)((intptr_t)dt->d_val + iBaseDiff);
+ iSymCount = hashtable[1];
break;
}
}
SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
}
+
+ // Apply base offset to locally defined symbols
+ // - #0 is defined as ("" SHN_UNDEF), so skip it
+ for( int i = 1; i < iSymCount; i ++ )
+ {
+ Elf32_Sym *sym = &dynsymtab[i];
+ const char *name = dynstrtab + sym->st_name;
+ (void)name;
+ if( sym->st_shndx == SHN_UNDEF )
+ {
+ TRACE("Sym %i'%s' deferred (SHN_UNDEF)", i, name);
+ }
+ else if( sym->st_shndx == SHN_ABS )
+ {
+ // Leave as is
+ SysDebug("Sym %i'%s' untouched", i, name);
+ }
+ else
+ {
+ void *newval;
+ size_t newsize;
+ if( ELF32_ST_BIND(sym->st_info) != STB_WEAK )
+ {
+ TRACE("Sym %i'%s' %p += 0x%x", i, name, sym->st_value, iBaseDiff);
+ sym->st_value += iBaseDiff;
+ }
+ else if( !GetSymbol(name, &newval, &newsize, Base) )
+ {
+ TRACE("Sym %i'%s' %p += 0x%x (Local weak)", i, name, sym->st_value, iBaseDiff);
+ sym->st_value += iBaseDiff;
+ }
+ else
+ {
+ TRACE("Sym %i'%s' %p = %p+0x%x (Extern weak)", i, name, newval, newsize);
+ sym->st_value = (uintptr_t)newval;
+ sym->st_size = newsize;
+ }
+ }
+ }
// === Add to loaded list (can be imported now) ===
AddLoaded( Filename, Base );
// === Parse Relocation Data ===
- DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
- for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
+ TRACE("dynamicTab = 0x%x", dynamicTab);
+ for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
{
- switch(dynamicTab[j].d_tag)
+ const Elf32_Dyn *dt = &dynamicTab[j];
+ switch(dt->d_tag)
{
// --- Shared Library Name ---
case DT_SONAME:
- DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
+ TRACE(".so Name '%s'", dynstrtab + dt->d_val);
break;
// --- Needed Library ---
case DT_NEEDED:
- libPath = dynstrtab + dynamicTab[j].d_val;
- DEBUGS(" Required Library '%s'", libPath);
+ //assert(dt->d_val <= sizeof_dynstrtab);
+ libPath = dynstrtab + dt->d_val;
+ TRACE(" Required Library '%s'", libPath);
if(LoadLibrary(libPath, NULL, envp) == 0) {
- #if DEBUG
- DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
- #else
SysDebug("Unable to load required library '%s'", libPath);
- #endif
return 0;
}
- DEBUGS(" Lib loaded");
+ TRACE(" Lib loaded");
break;
// --- PLT/GOT ---
-// case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
- case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
- case DT_PLTREL: pltType = dynamicTab[j].d_val; break;
- case DT_PLTRELSZ: pltSz = dynamicTab[j].d_val; break;
+// case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dt->d_val); break;
+ case DT_JMPREL: plt = (void*)(iBaseDiff + dt->d_val); break;
+ case DT_PLTREL: pltType = dt->d_val; break;
+ case DT_PLTRELSZ: pltSz = dt->d_val; break;
// --- Relocation ---
- case DT_REL: rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
- case DT_RELSZ: relSz = dynamicTab[j].d_val; break;
- case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
- case DT_RELA: rela = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
- case DT_RELASZ: relaSz = dynamicTab[j].d_val; break;
- case DT_RELAENT: relaEntSz = dynamicTab[j].d_val; break;
+ case DT_REL: rel = (void*)(iBaseDiff + dt->d_val); break;
+ case DT_RELSZ: relSz = dt->d_val; break;
+ case DT_RELENT: relEntSz = dt->d_val; break;
+ case DT_RELA: rela = (void*)(iBaseDiff + dt->d_val); break;
+ case DT_RELASZ: relaSz = dt->d_val; break;
+ case DT_RELAENT: relaEntSz = dt->d_val; break;
// --- Symbol Table ---
case DT_SYMTAB:
// --- Unknown ---
default:
- if(dynamicTab[j].d_tag > DT_JMPREL) continue;
+ if(dt->d_tag > DT_JMPREL) continue;
//DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
// i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
break;
}
}
- DEBUGS(" elf_relocate: Beginning Relocation");
-
- void elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
+ // Resolve symbols (second pass)
+ // - #0 is defined as ("" SHN_UNDEF), so skip it
+ int fail = 0;
+ for( int i = 1; i < iSymCount; i ++ )
{
- intptr_t val;
- switch( type )
+ Elf32_Sym *sym = &dynsymtab[i];
+ const char *name = dynstrtab + sym->st_name;
+ if( sym->st_shndx == SHN_UNDEF )
{
- // 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;
- 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;
- //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
- break;
-
- // Absolute Value of a symbol (S)
- 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;
- break;
-
- // Base Address (B+A)
- case R_386_RELATIVE:
- DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
- *ptr = iBaseDiff + addend;
- break;
-
- 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);
- break; }
-
- default:
- SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
- break;
+ void *newval;
+ size_t newsize;
+ if( !GetSymbol(name, &newval, &newsize, Base) ) {
+ if( ELF32_ST_BIND(sym->st_info) != STB_WEAK ) {
+ // Not a weak binding, set fail and move on
+ WARNING("Elf32Relocate: Can't find required symbol '%s' for '%s'",
+ name, Filename);
+ fail = 1;
+ continue ;
+ }
+ // Leave the symbol value as-is
+ }
+ else {
+ TRACE("Sym %i'%s' bound to %p+0x%x", i, name, newval, newsize);
+ sym->st_value = (intptr_t)newval;
+ sym->st_size = newsize;
+ }
}
- }
-
- void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
- {
- uint32_t val;
- switch(type)
+ else if( sym->st_shndx == SHN_ABS )
{
- // (S + A) | T
- 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);
- *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);
- *ptr = val + addend;
- break;
- default:
- SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
- break;
+ // Leave as is
+ }
+ else
+ {
+ // Handled previously
+ // TODO: What about weak locally-defined symbols?
+ //assert( ELF32_ST_BIND(sym->st_info) != STB_WEAK );
}
}
-
- 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);
+ if( fail ) {
+ WARNING("Relocation of '%s' failed", Filename);
+ return NULL;
}
+
+ TRACE("Beginning Relocation on '%s'", Filename);
+
+ tElf32RelocFcn *do_relocate;
switch(hdr->machine)
{
case EM_386:
break;
default:
SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
+ do_relocate = elf_doRelocate_unk;
+ fail = 1;
break;
}
+ TRACE("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
+
+ #define _doRelocate(r_info, ptr, bRela, addend) \
+ do_relocate(&reloc_info, r_info, ptr, addend, bRela);
+
+ tElfRelocInfo reloc_info = {
+ .Base = Base,
+ .iBaseDiff = iBaseDiff,
+ .strtab = dynstrtab,
+ .symtab = dynsymtab
+ };
+
// Parse Relocation Entries
if(rel && relSz)
{
Elf32_Word *ptr;
- DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
- j = relSz / relEntSz;
- for( i = 0; i < j; i++ )
+ TRACE("rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
+ int max = relSz / relEntSz;
+ for( int i = 0; i < max; i++ )
{
- //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
if(rela && relaSz)
{
Elf32_Word *ptr;
- DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
- j = relaSz / relaEntSz;
- for( i = 0; i < j; i++ )
+ TRACE("rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
+ int count = relaSz / relaEntSz;
+ for( int i = 0; i < count; 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);
}
}
if(plt && pltSz)
{
Elf32_Word *ptr;
- DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
+ TRACE("Relocate PLT, plt=0x%x", plt);
if(pltType == DT_REL)
{
Elf32_Rel *pltRel = plt;
- j = pltSz / sizeof(Elf32_Rel);
- DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
- for(i=0;i<j;i++)
+ int count = pltSz / sizeof(Elf32_Rel);
+ TRACE("PLT Reloc Type = Rel, %i entries", count);
+ for(int i = 0; i < count; 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
{
Elf32_Rela *pltRela = plt;
- j = pltSz / sizeof(Elf32_Rela);
- DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
- for(i=0;i<j;i++)
+ int count = pltSz / sizeof(Elf32_Rela);
+ TRACE("PLT Reloc Type = Rela, %i entries", count);
+ for(int i=0;i<count;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);
}
}
}
-
- DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
+
+ // Re-set readonly
+ for( int 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 ) {
+ TRACE("ElfRelocate: Failure");
+ return NULL;
+ }
+
+ #undef _doRelocate
+
+ TRACE("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)
+int Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff)
{
- Elf32_Ehdr *hdr = Base;
- Elf32_Sym *symtab;
- int nbuckets = 0;
-// int iSymCount = 0;
- int i;
- Elf32_Word *pBuckets;
- Elf32_Word *pChains;
- uint32_t iNameHash;
- const char *dynstrtab;
- uintptr_t iBaseDiff = -1;
- Elf32_Phdr *phtab;
Elf32_Dyn *dynTab = NULL;
-
- // Locate the tables
- phtab = (void*)( Base + hdr->phoff );
- for( i = 0; i < hdr->phentcount; i ++ )
+ uintptr_t iBaseDiff = -1;
+ Elf32_Ehdr *hdr = Base;
+ Elf32_Phdr *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
+ for( int i = 0; i < hdr->phentcount; i ++ )
{
if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
iBaseDiff = phtab[i].VAddr;
}
if( !dynTab ) {
SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
- return 0;
+ return 1;
}
iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
- for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
+ for( int i = 0; dynTab[i].d_tag != DT_NULL; i++)
{
switch(dynTab[i].d_tag)
{
// --- Symbol Table ---
case DT_SYMTAB:
- symtab = (void*)(intptr_t) dynTab[i].d_val; // Rebased in Relocate
+ *symtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff); // Rebased in Relocate
break;
case DT_STRTAB:
- dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
+ *dynstrtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
break;
// --- Hash Table --
case DT_HASH:
- pBuckets = (void*)(intptr_t) dynTab[i].d_val;
+ *pBuckets = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
break;
}
}
- nbuckets = pBuckets[0];
-// iSymCount = pBuckets[1];
+ if( !*symtab ) {
+ SysDebug("ERRO - No DT_SYMTAB in %p", Base);
+ return 1;
+ }
+ if( !*pBuckets ) {
+ SysDebug("ERRO - No DT_HASH in %p", Base);
+ return 1;
+ }
+ if( !*dynstrtab ) {
+ SysDebug("ERRO - No DT_STRTAB in %p", Base);
+ return 1;
+ }
+
+ // ... ok... maybe they haven't been relocated
+ if( (uintptr_t)*symtab < (uintptr_t)Base )
+ {
+ SysDebug("Executable not yet relocated (symtab,pBuckets,dynstrtab = %p,%p,%p + 0x%x)",
+ *symtab,*pBuckets,*dynstrtab, iBaseDiff);
+ *symtab = (void*)( (uintptr_t)*symtab + iBaseDiff );
+ *pBuckets = (void*)( (uintptr_t)*pBuckets + iBaseDiff );
+ *dynstrtab = (void*)( (uintptr_t)*dynstrtab + iBaseDiff );
+ }
+ *piBaseDiff = iBaseDiff;
+ return 0;
+}
+
+int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type)
+{
+ // Locate the tables
+ uintptr_t iBaseDiff = -1;
+ Elf32_Sym *symtab = NULL;
+ Elf32_Word *pBuckets = NULL;
+ const char *dynstrtab = NULL;
+ if( Elf32GetSymbolVars(Base, &symtab, &pBuckets, &dynstrtab, &iBaseDiff) )
+ return 1;
+
+ int nbuckets = pBuckets[0];
+// int iSymCount = pBuckets[1];
pBuckets = &pBuckets[2];
- pChains = &pBuckets[ nbuckets ];
-
+ Elf32_Word* pChains = &pBuckets[ nbuckets ];
+ assert(pChains);
+
// Get hash
- iNameHash = ElfHashString(Name);
+ int 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;
- if(Size) *Size = symtab[i].size;
- return 1;
- }
+ int idx = pBuckets[ iNameHash ];
+ do {
+ const Elf32_Sym *sym = &symtab[idx];
+ assert(sym);
+ if( strcmp(dynstrtab + sym->st_name, Name) == 0 )
+ {
+ TRACE("*sym = {value:0x%x,size:0x%x,info:0x%x,other:0x%x,shndx:%i}",
+ sym->st_value, sym->st_size, sym->st_info,
+ sym->st_other, sym->st_shndx);
+ if(Addr) *Addr = (void*)( sym->st_value );
+ if(Size) *Size = sym->st_size;
+ if(Binding) *Binding = ELF32_ST_BIND(sym->st_info);
+ if(Type) *Type = ELF32_ST_TYPE(sym->st_info);
+ if(Section) *Section = sym->st_shndx;
+ return 0;
+ }
+ } while( (idx = pChains[idx]) != STN_UNDEF && idx != pBuckets[iNameHash] );
- while(pChains[i] != STN_UNDEF)
+ TRACE("No symbol");
+ return 1;
+}
+
+int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
+{
+ int section;
+ TRACE("Elf32GetSymbol(%p,%s,...)", Base, Name);
+ if( Elf32GetSymbolInfo(Base, Name, ret, Size, §ion, NULL, NULL) )
+ return 0;
+ if( section == SHN_UNDEF ) {
+ TRACE("Elf32GetSymbol: Undefined", *ret, (Size?*Size:0), section);
+ return 0;
+ }
+ TRACE("Elf32GetSymbol: Found %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
+ 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 )
{
- i = pChains[i];
- if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
- *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
- if(Size) *Size = symtab[i].size;
- return 1;
- }
+ case R_X86_64_NONE:
+ break;
+ case R_X86_64_64:
+ if( !GetSymbol(symname, &symval, NULL, NULL) ) return 1;
+ *(uint64_t*)ptr = (uintptr_t)symval + addend;
+ break;
+ case R_X86_64_COPY: {
+ size_t size;
+ if( !GetSymbol(symname, &symval, &size, NULL) ) return 1;
+ memcpy(ptr, symval, size);
+ } break;
+ case R_X86_64_GLOB_DAT:
+ if( !GetSymbol(symname, &symval, NULL, NULL) ) return 1;
+ *(uint64_t*)ptr = (uintptr_t)symval;
+ break;
+ case R_X86_64_JUMP_SLOT:
+ if( !GetSymbol(symname, &symval, NULL, 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;
}
-#ifdef SUPPORT_ELF64
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;
void *pltrel = NULL;
int plt_size = 0, plt_type = 0;
- DEBUGS("Elf64Relocate: hdr = {");
- DEBUGS("Elf64Relocate: e_ident = '%.16s'", hdr->e_ident);
- DEBUGS("Elf64Relocate: e_type = 0x%x", hdr->e_type);
- DEBUGS("Elf64Relocate: e_machine = 0x%x", hdr->e_machine);
- DEBUGS("Elf64Relocate: e_version = 0x%x", hdr->e_version);
- DEBUGS("Elf64Relocate: e_entry = %p", hdr->e_entry);
- DEBUGS("Elf64Relocate: e_phoff = 0x%llx", hdr->e_phoff);
- DEBUGS("Elf64Relocate: e_shoff = 0x%llx", hdr->e_shoff);
- DEBUGS("Elf64Relocate: e_flags = 0x%x", hdr->e_flags);
- DEBUGS("Elf64Relocate: e_ehsize = 0x%x", hdr->e_ehsize);
- DEBUGS("Elf64Relocate: e_phentsize = 0x%x", hdr->e_phentsize);
- DEBUGS("Elf64Relocate: e_phnum = %i", hdr->e_phnum);
+ TRACE("hdr = {");
+ TRACE(" e_ident = '%.16s'", hdr->e_ident);
+ TRACE(" e_type = 0x%x", hdr->e_type);
+ TRACE(" e_machine = 0x%x", hdr->e_machine);
+ TRACE(" e_version = 0x%x", hdr->e_version);
+ TRACE(" e_entry = %p", hdr->e_entry);
+ TRACE(" e_phoff = 0x%llx", hdr->e_phoff);
+ TRACE(" e_shoff = 0x%llx", hdr->e_shoff);
+ TRACE(" e_flags = 0x%x", hdr->e_flags);
+ TRACE(" e_ehsize = 0x%x", hdr->e_ehsize);
+ TRACE(" e_phentsize = 0x%x", hdr->e_phentsize);
+ TRACE(" 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)
baseDiff = (uintptr_t)Base - compiledBase;
- DEBUGS("baseDiff = %p", baseDiff);
+ TRACE("baseDiff = %p", baseDiff);
if(dyntab == NULL) {
SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
// Second pass on dynamic table
for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
{
- DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
+ TRACE("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
switch(dyntab[i].d_tag)
{
case DT_SONAME: break;
case DT_NEEDED: {
char *libPath = strtab + dyntab[i].d_un.d_val;
- DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
+ TRACE("Elf64Relocate: libPath = '%s'", libPath);
if(LoadLibrary(libPath, NULL, envp) == 0) {
SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
return NULL;
}
}
+ // TODO: Relocate symbols
+
// 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);
+ TRACE("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);
}
}
if( rela )
{
- DEBUGS("rela_count = %i", rela_count);
+ TRACE("rela_count = %i", rela_count);
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 );
}
}
if( plt_type == DT_REL ) {
Elf64_Rel *plt = pltrel;
int count = plt_size / sizeof(Elf64_Rel);
- DEBUGS("plt rel count = %i", count);
+ TRACE("plt rel count = %i", count);
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 {
Elf64_Rela *plt = pltrel;
int count = plt_size / sizeof(Elf64_Rela);
- DEBUGS("plt rela count = %i", count);
+ TRACE("plt rela count = %i", count);
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 ) {
+ TRACE("Failure");
+ return NULL;
+ }
+
{
void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
- DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
+ TRACE("Relocations done, return %p", ret);
return 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);
+ TRACE("%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);
+ TRACE("%s = %p", Name, *Ret);
return 1;
}
}
}
#endif
-
uint32_t ElfHashString(const char *name)
{
uint32_t h = 0, g;
git.ucc.asn.au / tpg / acess2.git / blobdiff
UCC git Repository :: git.ucc.asn.au