X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Usermode%2FLibraries%2Fld-acess.so_src%2Felf.c;h=e3109b4a624eb386ef1534dd0b669880c557aa67;hb=89fa44978be88e59366ee3e8939a1621f1ebc146;hp=995d5ea7386a22500244c5483a594d9f88e35e07;hpb=92e1384ea0be30ae9ab82af6864da2806286e864;p=tpg%2Facess2.git diff --git a/Usermode/Libraries/ld-acess.so_src/elf.c b/Usermode/Libraries/ld-acess.so_src/elf.c index 995d5ea7..e3109b4a 100644 --- a/Usermode/Libraries/ld-acess.so_src/elf.c +++ b/Usermode/Libraries/ld-acess.so_src/elf.c @@ -4,39 +4,72 @@ * * elf.c * - ELF32/ELF64 relocation + * + * TODO: Have GetSymbol() return a symbol "strength" on success. Allows STB_WEAK to be overriden by STB_GLOBAL */ -#define DEBUG 0 +#ifndef KERNEL_VERSION +# define DEBUG 0 +#endif + +#ifndef PAGE_SIZE +# define PAGE_SIZE 4096 +#endif #include "common.h" #include +#ifndef assert +# include +#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 +#define TRACE(f,...) DEBUG_OUT("TRACE:%s "f, __func__,## __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 === @@ -83,112 +116,127 @@ int ElfGetSymbol(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(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela) { - intptr_t val; - switch( type ) + 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: - val = (intptr_t) GetSymbol(Sym, NULL); - DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')", - ptr, val, Sym); - *ptr = val + addend; + 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: - 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; + 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: - 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; + TRACE("R_386_JMP_SLOT *0x%x = %p", ptr, symval); + *ptr = (intptr_t)symval; 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; + TRACE("R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, Info->iBaseDiff, addend); + *ptr = Info->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); + 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: - SysDebug("elf_doRelocate_386: Unknown relocation %i", type); - break; + WARNING("Unknown relocation %i", ELF32_ST_TYPE(r_info)); + 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(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela) { - uint32_t val; - switch(type) + 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: - DEBUGS(" elf_doRelocate_arm: R_ARM_ABS32 %p (%s + %x)", ptr, Sym, addend); - val = (intptr_t)GetSymbol(Sym, NULL); + TRACE("R_ARM_ABS32 %p (%p + %x)", ptr, symval, addend); *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); + TRACE("R_ARM_GLOB_DAT %p (%p + %x)", ptr, symval, addend); *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); + TRACE("R_ARM_JUMP_SLOT %p (%p + %x)", ptr, symval, addend); *ptr = val + addend; break; // Copy - case R_ARM_COPY: { - size_t size; - void *src = GetSymbol(Sym, &size); - DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size); - memcpy(ptr, src, size); - break; } + 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: - if(Sym[0] != '\0') { + 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 - SysDebug("elf_doRelocate_arm: TODO - Implment R_ARM_RELATIVE for symbols"); + WARNING("TODO - Implment R_ARM_RELATIVE for symbols"); + return 2; } else { - *ptr = iBaseDiff + addend; + *ptr = Info->iBaseDiff + addend; } break; default: - SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type); - break; + 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; @@ -196,76 +244,91 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename) 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, intptr_t iBaseDiff); - 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;iphoff ); + 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; + } + else { + WARNING("elf_relocate: Multiple PT_DYNAMIC segments"); } - dynamicTab = (void *) (intptr_t) phtab[i].VAddr; - j = i; // Save Dynamic Table ID + break; } } // Page Align real base iRealBase &= ~0xFFF; - DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase); // Adjust "Real" Base - iBaseDiff = (intptr_t)Base - iRealBase; - -// hdr->entrypoint += iBaseDiff; // Adjust Entrypoint - + const intptr_t iBaseDiff = (intptr_t)Base - iRealBase; + + TRACE("True Base = 0x%x, Compiled Base = 0x%x, Difference = 0x%x", Base, iRealBase, iBaseDiff); + // 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; } } @@ -274,47 +337,85 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename) 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 (local)", i, name, sym->st_value + iBaseDiff); + sym->st_value += iBaseDiff; + } + // If GetSymbol doesn't return a strong/global symbol value + else if( GetSymbol(name, &newval, &newsize, Base) != 1 ) + { + TRACE("Sym %i'%s' = %p (Local weak)", i, name, sym->st_value + iBaseDiff); + sym->st_value += iBaseDiff; + } + else + { + TRACE("Sym %i'%s' = %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: @@ -326,23 +427,60 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename) // --- 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 _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend) + // Resolve symbols (second pass) + // - #0 is defined as ("" SHN_UNDEF), so skip it + int fail = 0; + for( int i = 1; i < iSymCount; i ++ ) { - 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); + Elf32_Sym *sym = &dynsymtab[i]; + const char *name = dynstrtab + sym->st_name; + if( sym->st_shndx == SHN_UNDEF ) + { + 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; + } + } + else if( sym->st_shndx == SHN_ABS ) + { + // Leave as is + } + else + { + // Handled previously + // TODO: What about weak locally-defined symbols? + //assert( ELF32_ST_BIND(sym->st_info) != STB_WEAK ); + } + } + 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: @@ -353,34 +491,45 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename) 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); + 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); } } @@ -388,53 +537,61 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename) 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;ientrypoint + 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; @@ -444,65 +601,163 @@ int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size) } 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, binding; + TRACE("Elf32GetSymbol(%p,%s,...)", Base, Name); + if( Elf32GetSymbolInfo(Base, Name, ret, Size, §ion, &binding, NULL) ) + return 0; + if( section == SHN_UNDEF ) { + TRACE("Elf32GetSymbol: Undefined %p", *ret, (Size?*Size:0), section); + return 0; + } + if( binding == STB_WEAK ) { + TRACE("Elf32GetSymbol: Weak, return %p+0x%x,section=%i", *ret, (Size?*Size:0), section); + return 2; + } + 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; @@ -514,21 +769,21 @@ void *Elf64Relocate(void *Base, char **envp, const char *Filename) 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) @@ -539,7 +794,7 @@ void *Elf64Relocate(void *Base, char **envp, const char *Filename) 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); @@ -580,14 +835,14 @@ void *Elf64Relocate(void *Base, char **envp, const char *Filename) // 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; @@ -636,56 +891,30 @@ void *Elf64Relocate(void *Base, char **envp, const char *Filename) } } + // 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 ); } } @@ -694,28 +923,33 @@ void *Elf64Relocate(void *Base, char **envp, const char *Filename) 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; } } @@ -745,7 +979,7 @@ int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size) 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) @@ -792,9 +1026,9 @@ int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size) // 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; } @@ -802,9 +1036,9 @@ int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size) { 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; } } @@ -813,7 +1047,6 @@ int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size) } #endif - uint32_t ElfHashString(const char *name) { uint32_t h = 0, g;