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- Rewritten relocation code to not make invalid assumptions (".reloc" section name) and to not unprotect second page (not needed really).
svn path=/trunk/; revision=9884
This commit is contained in:
Filip Navara
parent
e4c1673f80
commit
399da20296
1 changed files with 68 additions and 167 deletions
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@ -1,4 +1,4 @@
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/* $Id: utils.c,v 1.93 2004/06/26 11:23:32 ekohl Exp $
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/* $Id: utils.c,v 1.94 2004/06/26 14:37:05 navaraf Exp $
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*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS kernel
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@ -1224,187 +1224,88 @@ static NTSTATUS
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LdrPerformRelocations(PIMAGE_NT_HEADERS NTHeaders,
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PVOID ImageBase)
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{
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USHORT NumberOfEntries;
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PUSHORT pValue16;
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ULONG RelocationRVA;
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ULONG Delta32;
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ULONG Offset;
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PULONG pValue32;
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PRELOCATION_DIRECTORY RelocationDir;
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PRELOCATION_ENTRY RelocationBlock;
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int i;
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PIMAGE_DATA_DIRECTORY RelocationDDir;
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ULONG OldProtect;
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PVOID ProtectBase;
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ULONG ProtectSize;
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ULONG OldProtect2;
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PVOID ProtectBase2;
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ULONG ProtectSize2;
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PIMAGE_BASE_RELOCATION RelocationDir, RelocationEnd;
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ULONG Count, ProtectSize, OldProtect, i;
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PVOID Page, ProtectPage;
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PWORD TypeOffset;
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ULONG Delta = (ULONG_PTR)ImageBase - NTHeaders->OptionalHeader.ImageBase;
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NTSTATUS Status;
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PIMAGE_SECTION_HEADER Sections;
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ULONG MaxExtend;
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ULONG RelocationBlockOffset;
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ULONG RelocationSectionSize;
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if (NTHeaders->FileHeader.Characteristics & IMAGE_FILE_RELOCS_STRIPPED)
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{
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return STATUS_UNSUCCESSFUL;
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}
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Sections =
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(PIMAGE_SECTION_HEADER)((PVOID)NTHeaders + sizeof(IMAGE_NT_HEADERS));
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MaxExtend = 0;
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RelocationSectionSize = 0;
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for (i = 0; i < NTHeaders->FileHeader.NumberOfSections; i++)
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{
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if (!(Sections[i].Characteristics & IMAGE_SECTION_NOLOAD))
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{
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ULONG Extend;
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Extend =
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(ULONG)(Sections[i].VirtualAddress + Sections[i].Misc.VirtualSize);
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MaxExtend = max(MaxExtend, Extend);
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}
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if (!memcmp(Sections[i].Name,".reloc", 6))
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{
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RelocationSectionSize = Sections[i].Misc.VirtualSize;
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DPRINT("Relocation section size: %lx\n", RelocationSectionSize);
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}
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}
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RelocationDDir =
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&NTHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC];
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RelocationRVA = RelocationDDir->VirtualAddress;
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if (RelocationRVA)
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if (RelocationDDir->VirtualAddress == 0 || RelocationDDir->Size == 0)
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{
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RelocationDir =
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(PRELOCATION_DIRECTORY)((PCHAR)ImageBase + RelocationRVA);
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return STATUS_SUCCESS;
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}
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ProtectSize = PAGE_SIZE;
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RelocationDir = (IMAGE_BASE_RELOCATION*)((ULONG_PTR)ImageBase +
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RelocationDDir->VirtualAddress);
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RelocationEnd = (IMAGE_BASE_RELOCATION*)((ULONG_PTR)ImageBase +
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RelocationDDir->VirtualAddress + RelocationDDir->Size);
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while (RelocationDir < RelocationEnd &&
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RelocationDir->SizeOfBlock > 0)
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{
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Count = (RelocationDir->SizeOfBlock - sizeof(IMAGE_BASE_RELOCATION)) /
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sizeof(WORD);
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Page = ImageBase + RelocationDir->VirtualAddress;
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TypeOffset = (PWORD)(RelocationDir + 1);
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RelocationBlockOffset = 0;
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while (RelocationBlockOffset < RelocationSectionSize)
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/* Unprotect the page we're about to relocate. */
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ProtectPage = Page;
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Status = NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectPage,
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&ProtectSize,
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PAGE_READWRITE,
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&OldProtect);
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if (!NT_SUCCESS(Status))
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{
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if (RelocationDir->VirtualAddress > MaxExtend)
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{
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RelocationRVA += RelocationDir->SizeOfBlock;
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RelocationDir =
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(PRELOCATION_DIRECTORY) (ImageBase + RelocationRVA);
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RelocationBlockOffset += RelocationDir->SizeOfBlock;
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continue;
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}
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Delta32 = (ULONG)(ImageBase - NTHeaders->OptionalHeader.ImageBase);
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RelocationBlock =
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(PRELOCATION_ENTRY) (RelocationRVA + ImageBase +
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sizeof (RELOCATION_DIRECTORY));
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NumberOfEntries =
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RelocationDir->SizeOfBlock - sizeof (RELOCATION_DIRECTORY);
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NumberOfEntries = NumberOfEntries / sizeof (RELOCATION_ENTRY);
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ProtectBase = ImageBase + RelocationDir->VirtualAddress;
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ProtectSize = PAGE_SIZE;
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Status = NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectBase,
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&ProtectSize,
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PAGE_READWRITE,
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&OldProtect);
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if (!NT_SUCCESS(Status))
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{
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DPRINT1("Failed to unprotect relocation target.\n");
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return(Status);
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}
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if (RelocationDir->VirtualAddress + PAGE_SIZE < MaxExtend)
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{
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ProtectBase2 = ImageBase + RelocationDir->VirtualAddress + PAGE_SIZE;
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ProtectSize2 = PAGE_SIZE;
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Status = NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectBase2,
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&ProtectSize2,
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PAGE_READWRITE,
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&OldProtect2);
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if (!NT_SUCCESS(Status))
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{
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DPRINT1("Failed to unprotect relocation target (2).\n");
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NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectBase,
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&ProtectSize,
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OldProtect,
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&OldProtect);
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return(Status);
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}
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}
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for (i = 0; i < NumberOfEntries; i++)
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{
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Offset = (RelocationBlock[i].TypeOffset & 0xfff);
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Offset += (ULONG)(RelocationDir->VirtualAddress + ImageBase);
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/*
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* What kind of relocations should we perform
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* for the current entry?
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*/
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switch (RelocationBlock[i].TypeOffset >> 12)
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{
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case TYPE_RELOC_ABSOLUTE:
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break;
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case TYPE_RELOC_HIGH:
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pValue16 = (PUSHORT)Offset;
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*pValue16 += Delta32 >> 16;
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break;
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case TYPE_RELOC_LOW:
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pValue16 = (PUSHORT)Offset;
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*pValue16 += Delta32 & 0xffff;
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break;
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case TYPE_RELOC_HIGHLOW:
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pValue32 = (PULONG)Offset;
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*pValue32 += Delta32;
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break;
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case TYPE_RELOC_HIGHADJ:
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/* FIXME: do the highadjust fixup */
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DPRINT("TYPE_RELOC_HIGHADJ fixup not implemented, sorry\n");
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return STATUS_UNSUCCESSFUL;
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default:
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DPRINT("unexpected fixup type\n");
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return STATUS_UNSUCCESSFUL;
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}
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}
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Status = NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectBase,
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&ProtectSize,
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OldProtect,
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&OldProtect);
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if (!NT_SUCCESS(Status))
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{
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DPRINT1("Failed to protect relocation target.\n");
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return(Status);
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}
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if (RelocationDir->VirtualAddress + PAGE_SIZE < MaxExtend)
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{
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Status = NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectBase2,
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&ProtectSize2,
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OldProtect2,
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&OldProtect2);
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if (!NT_SUCCESS(Status))
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{
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DPRINT1("Failed to protect relocation target2.\n");
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return(Status);
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}
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}
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RelocationRVA += RelocationDir->SizeOfBlock;
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RelocationDir =
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(PRELOCATION_DIRECTORY) (ImageBase + RelocationRVA);
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RelocationBlockOffset += RelocationDir->SizeOfBlock;
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DPRINT1("Failed to unprotect relocation target.\n");
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return(Status);
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}
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/* Patch the page. */
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for (i = 0; i < Count; i++)
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{
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SHORT Offset = TypeOffset[i] & 0xFFF;
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USHORT Type = TypeOffset[i] >> 12;
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switch (Type)
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{
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case IMAGE_REL_BASED_ABSOLUTE:
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break;
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case IMAGE_REL_BASED_HIGH:
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*(PUSHORT)(Page + Offset) += HIWORD(Delta);
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break;
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case IMAGE_REL_BASED_LOW:
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*(PUSHORT)(Page + Offset) += LOWORD(Delta);
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break;
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case IMAGE_REL_BASED_HIGHLOW:
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*(PULONG)(Page + Offset) += Delta;
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break;
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case IMAGE_REL_BASED_HIGHADJ:
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default:
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DPRINT("Unknown/unsupported fixup type %d.\n", type);
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return STATUS_UNSUCCESSFUL;
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}
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}
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/* Restore old page protection. */
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NtProtectVirtualMemory(NtCurrentProcess(),
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&ProtectPage,
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&ProtectSize,
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OldProtect,
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&OldProtect);
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RelocationDir = (IMAGE_BASE_RELOCATION*)((ULONG_PTR)RelocationDir +
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RelocationDir->SizeOfBlock);
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}
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return STATUS_SUCCESS;
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