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Code Issues Releases Wiki Activity

GP-4737 - Improve ELF relocation handling of unresolved symbol

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ghidra1 2024-06-26 12:50:25 -04:00
parent 72d4a342a6
commit 036ef9d0db
20 changed files with 529 additions and 306 deletions
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53
Ghidra/Processors/ARM/src/main/java/ghidra/app/util/bin/format/elf/relocation/ARM_ElfRelocationHandler.java
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@ -62,7 +62,6 @@ public class ARM_ElfRelocationHandler
boolean instructionBigEndian =
program.getLanguage().getLanguageDescription().getInstructionEndian().isBigEndian();
boolean isThumb = isThumb(sym);
long addend = relocation.getAddend(); // will be 0 for REL case
@ -71,6 +70,32 @@ public class ARM_ElfRelocationHandler
int newValue = 0;
int byteLength = 4; // most relocations affect 4-bytes (change if different)
// Handle relative relocations that do not require symbolAddr or symbolValue
switch (type) {
case R_ARM_RELATIVE: // Target class: Data
if (elfRelocationContext.extractAddend()) {
addend = memory.getInt(relocationAddress);
}
newValue =
(int) elfRelocationContext.getImageBaseWordAdjustmentOffset() + (int) addend;
memory.setInt(relocationAddress, newValue);
return new RelocationResult(Status.APPLIED, byteLength);
case R_ARM_COPY:
markAsUnsupportedCopy(program, relocationAddress, type, symbolName, symbolIndex,
sym.getSize(), elfRelocationContext.getLog());
return RelocationResult.UNSUPPORTED;
default:
break;
}
// Check for unresolved symbolAddr and symbolValue required by remaining relocation types handled below
if (handleUnresolvedSymbol(elfRelocationContext, relocation, relocationAddress)) {
return RelocationResult.FAILURE;
}
boolean isThumb = isThumb(sym);
switch (type) {
case R_ARM_PC24: { // Target class: ARM Instruction
int oldValue = memory.getInt(relocationAddress, instructionBigEndian);
@ -260,20 +285,19 @@ public class ARM_ElfRelocationHandler
case R_ARM_JUMP_SLOT: { // Target class: Data
// Corresponds to lazy dynamically linked external symbols within
// GOT/PLT symbolValue corresponds to PLT entry for which we need to
// create and external function location. Don't bother changing
// create an external function location. Don't bother changing
// GOT entry bytes if it refers to .plt block
Address symAddress = elfRelocationContext.getSymbolAddress(sym);
MemoryBlock block = memory.getBlock(symAddress);
MemoryBlock block = memory.getBlock(symbolAddr);
// TODO: jump slots are always in GOT - not sure why PLT check is done
boolean isPltSym = block != null && block.getName().startsWith(".plt");
boolean isExternalSym =
block != null && MemoryBlock.EXTERNAL_BLOCK_NAME.equals(block.getName());
if (!isPltSym) {
memory.setInt(relocationAddress, (int) symAddress.getOffset());
memory.setInt(relocationAddress, (int) symbolValue);
}
if (isPltSym || isExternalSym) {
Function extFunction = elfRelocationContext.getLoadHelper()
.createExternalFunctionLinkage(symbolName, symAddress, null);
.createExternalFunctionLinkage(symbolName, symbolAddr, null);
if (extFunction == null) {
markAsError(program, relocationAddress, type, symbolName, symbolIndex,
"Failed to create external function", elfRelocationContext.getLog());
@ -282,16 +306,7 @@ public class ARM_ElfRelocationHandler
}
break;
}
case R_ARM_RELATIVE: { // Target class: Data
if (elfRelocationContext.extractAddend()) {
addend = memory.getInt(relocationAddress);
}
newValue =
(int) elfRelocationContext.getImageBaseWordAdjustmentOffset() + (int) addend;
memory.setInt(relocationAddress, newValue);
break;
}
/*
case R_ARM_GOTOFF32: {
break;
@ -680,12 +695,6 @@ public class ARM_ElfRelocationHandler
}
*/
case R_ARM_COPY: {
markAsUnsupportedCopy(program, relocationAddress, type, symbolName, symbolIndex,
sym.getSize(), elfRelocationContext.getLog());
return RelocationResult.UNSUPPORTED;
}
default: {
markAsUnhandled(program, relocationAddress, type, symbolIndex, symbolName,
elfRelocationContext.getLog());