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Code Issues Releases Wiki Activity

GP-1403 only treat stored pointer offset as signed for "relative"

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pointer-type
This commit is contained in:
ghidra1 2022-04-11 22:09:33 -04:00
parent 6bcb417104
commit 17534b9c3f
1 changed files with 33 additions and 19 deletions
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52
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/PointerDataType.java
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@ -396,9 +396,13 @@ public class PointerDataType extends BuiltIn implements Pointer {
Memory mem = buf.getMemory();
// FIXME! Use signed offset for relative, unsigned by default
boolean signedOffset = false;
PointerType pointerType = PointerTypeSettingsDefinition.DEF.getType(settings);
if (pointerType == PointerType.RELATIVE) {
signedOffset = true;
}
Long offset = getStoredOffset(buf, size);
Long offset = getStoredOffset(buf, size, signedOffset);
if (offset == null) {
errorHandler.accept("Insufficient data");
return null;
@ -413,20 +417,24 @@ public class PointerDataType extends BuiltIn implements Pointer {
int shift = (int) OffsetShiftSettingsDefinition.DEF.getValue(settings);
if (shift < 0) {
addrOffset >>>= -shift; // avoid sign-extension
if (signedOffset) {
addrOffset >>= -shift; // signed right-shift
}
else {
addrOffset >>>= -shift; // unsigned right-shift
}
}
else {
addrOffset <<= shift;
addrOffset <<= shift; // left-shift
}
try {
PointerType choice = PointerTypeSettingsDefinition.DEF.getType(settings);
if (choice != PointerType.DEFAULT && spaceName != null) {
if (pointerType != PointerType.DEFAULT && spaceName != null) {
errorHandler.accept("Address Space and Pointer Type settings conflict");
return null;
}
// Address space setting ignored if Pointer Type has been specified
if (choice == PointerType.IMAGE_BASE_RELATIVE) {
if (pointerType == PointerType.IMAGE_BASE_RELATIVE) {
if (addrOffset == 0) {
// Done for consistency with old ImageBaseOffsetDataType.
// A 0 relative offset is considerd invalid (NaP)
@ -440,13 +448,13 @@ public class PointerDataType extends BuiltIn implements Pointer {
targetSpace = imageBase.getAddressSpace();
return imageBase.addWrap(addrOffset * targetSpace.getAddressableUnitSize());
}
else if (choice == PointerType.RELATIVE) {
else if (pointerType == PointerType.RELATIVE) {
// must ignore AddressSpaceSettingsDefinition
Address base = buf.getAddress();
targetSpace = base.getAddressSpace();
return base.addWrap(addrOffset * targetSpace.getAddressableUnitSize());
}
else if (choice == PointerType.FILE_OFFSET) {
else if (pointerType == PointerType.FILE_OFFSET) {
if (mem == null) {
errorHandler.accept("Memory not specified");
}
@ -469,8 +477,8 @@ public class PointerDataType extends BuiltIn implements Pointer {
}
return null;
}
else if (choice != PointerType.DEFAULT) {
errorHandler.accept("Unsupported pointer type: " + choice.toString());
else if (pointerType != PointerType.DEFAULT) {
errorHandler.accept("Unsupported pointer type: " + pointerType.toString());
return null;
}
@ -503,6 +511,8 @@ public class PointerDataType extends BuiltIn implements Pointer {
return getSegmentedAddressValue(buf, size, addrOffset);
}
// addrOffset treated as word offset when targetSpace addressable unitsize > 1
// TODO: May need setting to force treatment as byte-offset
return targetSpace.getAddress(addrOffset, true);
}
catch (IllegalArgumentException | AddressOutOfBoundsException e) {
@ -519,24 +529,30 @@ public class PointerDataType extends BuiltIn implements Pointer {
}
/**
* Get signed offset value based upon bytes stored at the specified buf
* location
* Get an offset value based upon bytes stored at the specified buf
* location.
*
* @param buf memory buffer and stored pointer location
* @param size store pointer size in bytes
* @param signed true if signed offset or false for unsigned
* @return stored offset value or null if unusable buf or data
*/
private static Long getStoredOffset(MemBuffer buf, int size) {
private static Long getStoredOffset(MemBuffer buf, int size, boolean signed) {
byte[] bytes = new byte[size];
if (buf.getBytes(bytes, 0) != size) {
return null;
}
return DataConverter.getInstance(buf.isBigEndian()).getSignedValue(bytes, size);
DataConverter converter = DataConverter.getInstance(buf.isBigEndian());
if (signed) {
return converter.getSignedValue(bytes, size);
}
return converter.getValue(bytes, size);
}
/**
* Generate an address value based upon bytes stored at the specified buf
* location
* location. The stored bytes will be interpreted as an unsigned byte
* offset into the specified targetSpace.
*
* @param buf memory buffer and stored pointer location
* @param size pointer size in bytes
@ -549,9 +565,7 @@ public class PointerDataType extends BuiltIn implements Pointer {
return null;
}
// FIXME! Use signed offset for relative, unsigned by default
Long offset = getStoredOffset(buf, size);
Long offset = getStoredOffset(buf, size, false);
if (offset == null) {
// Insufficient bytes
return null;