What causes "Invalid RPM package: tag ${tag} data is misaligned" in can1357/oh-my-pi?

Treat the file as corrupt: re-download or rebuild the .rpm package.

can1357/oh-my-pi · error · ArchiveError

Invalid RPM package: tag ${tag} data is misaligned

Error message

Invalid RPM package: tag ${tag} data is misaligned

What it means

Fixed-size numeric RPM tag data (INT16/INT32/INT64) must start at an offset aligned to its element size within the data region. This parser enforces natural alignment before reading multi-byte integers, so a misaligned offset indicates a corrupt or malformed header rather than risking misread values.

Source

Thrown at packages/utils/src/ar/rpm.ts:112

				throw new ArchiveError(`Invalid RPM package: string tag ${tag} has an invalid count`);
			}
			if (stringCount > remaining) {
				throw new ArchiveError(`Invalid RPM package: string tag ${tag} exceeds header data`);
			}
			let cursor = indexSize + offset;
			const limit = indexSize + intro.dataSize;
			for (let stringIndex = 0; stringIndex < stringCount; stringIndex++) {
				while (cursor < limit && body[cursor] !== 0) cursor++;
				if (cursor === limit) {
					throw new ArchiveError(`Invalid RPM package: string tag ${tag} is not NUL-terminated`);
				}
				cursor++;
			}
			continue;
		} else {
			throw new ArchiveError(`Invalid RPM package: tag ${tag} uses unknown data type ${type}`);
		}
		if (offset % elementSize !== 0) throw new ArchiveError(`Invalid RPM package: tag ${tag} data is misaligned`);
		if (count * elementSize > remaining)
			throw new ArchiveError(`Invalid RPM package: tag ${tag} exceeds header data`);
	}
}

function readHeaderString(
	body: Uint8Array,
	indexSize: number,
	dataSize: number,
	offset: number,
	count: number,
	type: number,
	tag: number,
): string {
	if (type !== RPM_TYPE_STRING || count !== 1) {
		throw new ArchiveError(`Invalid RPM package: tag ${tag} must contain one string`);
	}
	const start = indexSize + offset;

View on GitHub (pinned to 9690622007)

Solutions

Treat the file as corrupt: re-download or rebuild the .rpm package.
Verify with an independent RPM tool to confirm the header is malformed.
If your own build tooling writes the header, fix its offset/alignment bookkeeping (data is stored in tag order with natural alignment).
Catch ArchiveError around readRpm and reject the package gracefully.

Defensive patterns

Strategy: try-catch

Try / catch

try {
  const entries = await readRpm(source, options);
} catch (err) {
  if (err instanceof ArchiveError && err.message.includes("misaligned")) {
    return quarantine(file, "corrupt RPM header alignment");
  }
  throw err;
}

Prevention

Verify package checksums before parsing.
Avoid custom tooling that writes RPM headers manually; use rpmbuild.
Quarantine and report files that fail header validation instead of retrying.

When it happens

Trigger: readRpm()/parseMainHeader validates an index entry of type 3/4/5 whose offset field is not divisible by the element size (2/4/8) — e.g. an INT32 tag with offset 3.

Common situations: Bit-level corruption of the offset field; headers hand-assembled by buggy custom tooling; fuzzed inputs targeting integer-reading paths.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/a26d0f71a54e7f08. Report an issue: GitHub.