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Fix elf loading

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This commit is contained in:
Alex
2023-04-21 17:47:09 +03:00
parent 96a27f7bc8
commit f2eab6c64f
5 changed files with 119 additions and 24 deletions
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18
Execute/Elf/Parse.cpp
View File

@ -51,7 +51,7 @@ namespace Execute
return StringTable + Offset;
}
void *ELFLookupSymbol(Elf64_Ehdr *Header, const char *Name)
Elf64_Sym *ELFLookupSymbol(Elf64_Ehdr *Header, const char *Name)
{
Elf64_Shdr *SymbolTable = nullptr;
Elf64_Shdr *StringTable = nullptr;
@ -82,7 +82,7 @@ namespace Execute
Symbol = (Elf64_Sym *)((uintptr_t)Header + SymbolTable->sh_offset + (i * sizeof(Elf64_Sym)));
String = (char *)((uintptr_t)Header + StringTable->sh_offset + Symbol->st_name);
if (strcmp(String, Name) == 0)
return (void *)Symbol->st_value;
return Symbol;
}
return nullptr;
}
@ -108,7 +108,7 @@ namespace Execute
Elf64_Shdr *StringTable = GetELFSection(Header, SymbolTable->sh_link);
const char *Name = (const char *)Header + StringTable->sh_offset + Symbol->st_name;
void *Target = ELFLookupSymbol(Header, Name);
void *Target = (void *)ELFLookupSymbol(Header, Name)->st_value;
if (Target == nullptr)
{
if (ELF64_ST_BIND(Symbol->st_info) & STB_WEAK)
@ -165,6 +165,8 @@ namespace Execute
{
void *MemoryImage = nullptr;
Elf64_Ehdr *ELFHeader = (Elf64_Ehdr *)ElfFile;
bool IsPIC = ELFHeader->e_type == ET_DYN;
debug("Elf %s PIC", IsPIC ? "is" : "is not");
/* TODO: Not sure what I am supposed to do with this.
* It is supposed to detect if it's PIC or not but I
@ -195,15 +197,17 @@ namespace Execute
if (ItrPhdr.p_type == PT_LOAD && ItrPhdr.p_vaddr == 0)
{
debug("p_vaddr is 0, allocating %ld pages for image", TO_PAGES(Length));
MemoryImage = mem->RequestPages(TO_PAGES(Length + 1), true);
debug("p_vaddr is 0, allocating %ld pages for image (size: %#lx)", TO_PAGES(Length), Length);
MemoryImage = mem->RequestPages(TO_PAGES(Length), true);
debug("MemoryImage: %#lx-%#lx", MemoryImage, (uintptr_t)MemoryImage + Length);
memset(MemoryImage, 0, Length);
return {MemoryImage, (void *)FirstProgramHeaderVirtualAddress};
}
}
debug("Allocating %ld pages for image", TO_PAGES(Length));
MemoryImage = mem->RequestPages(TO_PAGES(Length + 1));
debug("Allocating %ld pages for image (size: %#lx)", TO_PAGES(Length), Length);
MemoryImage = mem->RequestPages(TO_PAGES(Length));
debug("MemoryImage: %#lx-%#lx", MemoryImage, (uintptr_t)MemoryImage + Length);
memset(MemoryImage, 0, Length);
if (FirstProgramHeaderVirtualAddress != 0)

89
Execute/Elf/SharedObjects.cpp
View File

@ -127,6 +127,95 @@ namespace Execute
debug("memcpy: %#lx => %#lx (%ld bytes)", (uint8_t *)LibFile + ItrProgramHeader.p_offset, (uintptr_t)MAddr, ItrProgramHeader.p_filesz);
break;
}
struct Elf64_Dyn *JmpRel = ELFGetDynamicTag((void *)LibFile, DT_JMPREL);
struct Elf64_Dyn *SymTab = ELFGetDynamicTag((void *)LibFile, DT_SYMTAB);
struct Elf64_Dyn *StrTab = ELFGetDynamicTag((void *)LibFile, DT_STRTAB);
if (!JmpRel)
{
debug("No DT_JMPREL");
}
if (!SymTab)
{
debug("No DT_SYMTAB");
}
if (!StrTab)
{
debug("No DT_STRTAB");
}
if (JmpRel && SymTab && StrTab)
{
debug("JmpRel: %#lx, SymTab: %#lx, StrTab: %#lx", JmpRel->d_un.d_ptr, SymTab->d_un.d_ptr, StrTab->d_un.d_ptr);
Elf64_Rela *_JmpRel = (Elf64_Rela *)(sl.MemoryImage + (JmpRel->d_un.d_ptr - BaseAddress));
Elf64_Sym *_SymTab = (Elf64_Sym *)(sl.MemoryImage + (SymTab->d_un.d_ptr - BaseAddress));
char *_DynStr = (char *)(sl.MemoryImage + (StrTab->d_un.d_ptr - BaseAddress));
Elf64_Shdr *gotSection = nullptr;
for (Elf64_Half i = 0; i < ((Elf64_Ehdr *)LibFile)->e_shnum; i++)
{
Elf64_Shdr *shdr = (Elf64_Shdr *)((uint8_t *)LibFile + ((Elf64_Ehdr *)LibFile)->e_shoff + i * sizeof(Elf64_Shdr));
if (shdr->sh_type == SHT_PROGBITS && (shdr->sh_flags & SHF_WRITE) && (shdr->sh_flags & SHF_ALLOC))
{
gotSection = shdr;
break;
}
}
debug("LIB_DBG");
if (gotSection)
{
Elf64_Xword numEntries = gotSection->sh_size / sizeof(Elf64_Addr);
for (Elf64_Xword i = 0; i < numEntries - 3; i++)
{
Elf64_Rela *Rel = _JmpRel + i;
Elf64_Addr *GOTEntry = (Elf64_Addr *)(Rel->r_offset + sl.MemoryImage);
Elf64_Xword RelType = ELF64_R_TYPE(Rel->r_info);
debug("r_offset: %#lx RelType: %d", Rel->r_offset, RelType);
switch (RelType)
{
case R_X86_64_NONE:
break;
case R_X86_64_JUMP_SLOT:
{
Elf64_Xword SymIndex = ELF64_R_SYM(Rel->r_info);
Elf64_Sym *Sym = _SymTab + SymIndex;
if (Sym->st_name)
{
char *SymName = _DynStr + Sym->st_name;
debug("SymName: %s", SymName);
Elf64_Sym *LibSym = ELFLookupSymbol((Elf64_Ehdr *)LibFile, SymName);
if (LibSym)
{
*GOTEntry = (Elf64_Addr)(sl.MemoryImage + LibSym->st_value);
debug("GOT[%ld]: %#lx + %#lx = %#lx", i, sl.MemoryImage, LibSym->st_value, *GOTEntry);
}
}
break;
}
default:
{
fixme("RelType %d not supported", RelType);
break;
}
}
debug("GOT[%ld](%#lx): %#lx", i, GOTEntry, *GOTEntry);
}
}
else
debug("GOT section not found");
}
}
sl.Address = r_cst(uint64_t, LibFile);