NationalSecurityAgency/ghidra · error · IllegalArgumentException

Byte arrays cannot exceed length of variable

Error message

Byte arrays cannot exceed length of variable

What it means

Thrown by AbstractDebuggerVariableViewerVarValue.setRawValueBytes when the supplied byte array is longer than the variable's own value buffer. The variable has a fixed length; the caller must truncate or pad to fit, never exceed.

Source

Thrown at Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/gui/variable/AbstractDebuggerVariableViewerVarValue.java:121

					new ByteMemBufferImpl(address, value, language.isBigEndian()), NO_SETTINGS,
					value.length);
			setRawValueBytes(encoded);
		}
		catch (final DataTypeEncodeException e) {
			Msg.error(this, e.getMessage());
		}
	}

	abstract DataType getDataType();

	abstract void setDataType(DataType dataType);

	private void setRawValueBytes(byte[] bytes) {
		if (address == null) {
			throw new IllegalStateException("Cannot write to variable without an address");
		}
		if (bytes.length > value.length) {
			throw new IllegalArgumentException("Byte arrays cannot exceed length of variable");
		}
		if (bytes.length < value.length) {
			final byte[] fillOld = Arrays.copyOf(value, value.length);
			System.arraycopy(bytes, 0, fillOld, 0, bytes.length);
			bytes = fillOld;
		}
		final DebuggerControlService controlService = provider.controlService;
		if (controlService == null) {
			throw new AssertionError("No control service");
		}
		final DebuggerControlService.StateEditor editor =
				controlService.createStateEditor(provider.currentCoordinates);
		editor.setVariable(address, bytes).exceptionally(ex -> {
			Msg.showError(this, null, "Write Failed", "Could not modify value (on target)", ex);
			return null;
		});

	}

View on GitHub (pinned to d5f144c24d)

Solutions

1. Truncate or resize the byte array to the variable's length (value.length) before calling setRawValueBytes.
2. Validate input length against the variable's DataType length in the UI before submission.
3. Change the variable's declared type to a wider one if more bytes are genuinely required.
4. Use NumericUtilities to convert a number to a fixed-width byte array of the correct length.

Example fix

// before
byte[] bytes = ...; // possibly too long
setRawValueBytes(bytes); // throws if bytes.length > value.length

// after
if (bytes.length > value.length) {
    bytes = Arrays.copyOf(bytes, value.length);
}
setRawValueBytes(bytes);

boolean ok = bytes.length <= value.length;

static boolean fitsVariable(byte[] bytes, byte[] value) {
    return bytes.length <= value.length;
}

try {
    varValue.setRawValueBytes(bytes);
} catch (IllegalArgumentException e) {
    bytes = Arrays.copyOf(bytes, value.length);
}

When it happens

Trigger: Calling setRawValueBytes(bytes) where bytes.length > value.length (value is the variable's fixed-size backing buffer derived from its DataType length).

Common situations: Paste of a hex string that decodes to more bytes than the variable's type; programming error converting a wider integer into a narrower variable; mismatch between the declared variable size and the bytes supplied by the UI.

Related errors

• Byte arrays cannot exceed length of variable
• Byte array values must be hex enclosed in {}
• data and mask must have same capacity
• Length must match the register
• Space must be a memory, register, or NO_ADDRESS space

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/123640f38584c624. Report an issue: GitHub.