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OcAppleKernelLib: Process indirect symbols.

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This commit is contained in:
Download-Fritz 2019-03-28 19:18:05 +01:00
parent 25ea29a92d
commit eee3a46295
1 changed files with 91 additions and 1 deletions
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92
Library/OcAppleKernelLib/Link.c
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@ -947,7 +947,6 @@ InternalRelocateAndCopyRelocations64 (
ASSERT (Kext != NULL);
ASSERT (SourceRelocations != NULL);
ASSERT (NumRelocations != NULL);
ASSERT (NumRelocations > 0);
ASSERT (TargetRelocations != NULL);
PreservedRelocations = 0;
@ -1089,6 +1088,92 @@ InternalRelocateSymbols (
return TRUE;
}
/**
process_symbol_pointers
**/
STATIC
BOOLEAN
InternalProcessSymbolPointers (
IN OC_MACHO_CONTEXT *MachoContext,
IN CONST MACH_DYSYMTAB_COMMAND *DySymtab,
IN UINT64 LoadAddress
)
{
CONST MACH_HEADER_64 *MachHeader;
UINT32 MachSize;
CONST MACH_SECTION_64 *Section;
UINT32 NumSymbols;
UINT32 FirstSym;
BOOLEAN Result;
UINT32 OffsetTop;
CONST UINT32 *SymIndex;
CHAR8 *SymPtr;
UINT32 Index;
CONST MACH_NLIST_64 *Symbol;
Section = MachoGetSegmentSectionByName64 (
MachoContext,
"__DATA",
"__nl_symbol_ptr"
);
if (Section == NULL) {
return TRUE;
}
NumSymbols = (Section->Size / sizeof (MACH_NLIST_64));
FirstSym = Section->Reserved1;
Result = OcOverflowAddU32 (FirstSym, NumSymbols, &OffsetTop);
if (Result || (OffsetTop > DySymtab->NumIndirectSymbols)) {
return FALSE;
}
MachSize = MachoGetFileSize (MachoContext);
Result = OcOverflowMulAddU32 (
DySymtab->NumIndirectSymbols,
sizeof (MACH_NLIST_64),
DySymtab->IndirectSymbolsOffset,
&OffsetTop
);
if (Result || (OffsetTop > MachSize)) {
return FALSE;
}
MachHeader = MachoGetMachHeader64 (MachoContext);
ASSERT (MachHeader != NULL);
//
// Iterate through the indirect symbol table and fill in the section of
// symbol pointers. There are three cases:
// 1) A normal symbol - put its value directly in the table
// 2) An INDIRECT_SYMBOL_LOCAL - symbols that are local and already have
// their offset from the start of the file in the section. Simply
// add the file's link address to fill this entry.
// 3) An INDIRECT_SYMBOL_ABS - prepopulated absolute symbols. No
// action is required.
//
SymIndex = (UINT32 *)((UINTN)MachHeader + DySymtab->IndirectSymbolsOffset);
SymIndex += FirstSym;
SymPtr = (CHAR8 *)((UINTN)MachHeader + Section->Offset);
for (Index = 0; Index < NumSymbols; ++Index, SymPtr += sizeof (MACH_NLIST_64)) {
if ((*SymIndex & MACH_INDIRECT_SYMBOL_LOCAL) != 0) {
if ((*SymIndex & MACH_INDIRECT_SYMBOL_ABS) != 0) {
continue;
}
*(UINT64 *)SymPtr += LoadAddress;
} else {
Symbol = MachoGetSymbolByIndex64 (MachoContext, *SymIndex);
if (Symbol == NULL) {
return FALSE;
}
*(UINT64 *)SymPtr += Symbol->Value;
}
}
return TRUE;
}
/**
Prelinks the specified KEXT against the specified LoadAddress and the data
@ -1322,6 +1407,11 @@ InternalPrelinkKext64 (
if (FirstSegment == NULL) {
return RETURN_UNSUPPORTED;
}
Result = InternalProcessSymbolPointers (MachoContext, DySymtab, LoadAddress);
if (!Result) {
return RETURN_LOAD_ERROR;
}
//
// Copy the relocations to be reserved and adapt the symbol number they
// reference in case it has been relocated above.