archive

Documentation

Overview

Package archive handles unpacking .deb files (a Unix "ar" archive containing debian-binary, control.tar.*, and data.tar.*) and safely extracting the compressed tarballs inside, guarding against path traversal, symlink escapes, and decompression bombs.

Index

• func Decompress(name string, r io.Reader) (io.Reader, error)
• func SafeExtractTar(r io.Reader, destDir string, filter FilterFunc) ([]string, error)
• type ArEntry
  • func FindMember(entries []ArEntry, prefixes ...string) (*ArEntry, bool)
  • func ParseAr(data []byte) ([]ArEntry, error)
• type FilterFunc

Functions

func Decompress

func Decompress(name string, r io.Reader) (io.Reader, error)

Decompress wraps r with the decompressor matching the data.tar.* suffix found on member.Name (.gz, .xz, .zst), or returns r unchanged for a plain .tar member.

func SafeExtractTar

func SafeExtractTar(r io.Reader, destDir string, filter FilterFunc) ([]string, error)

SafeExtractTar reads a tar stream and writes selected entries under destDir, rejecting anything that would escape destDir (path traversal, absolute paths, symlink/hardlink targets outside destDir) and enforcing a total-size cap.

Types

type ArEntry

type ArEntry struct {
	Name string
	Data []byte
}

ArEntry is one member of a Unix ar archive.

func FindMember

func FindMember(entries []ArEntry, prefixes ...string) (*ArEntry, bool)

FindMember returns the first member whose name starts with any of the given prefixes (used to locate "data.tar" regardless of its compression suffix: .gz, .xz, .zst).

func ParseAr

func ParseAr(data []byte) ([]ArEntry, error)

ParseAr splits a .deb (or any ar archive) into its named members.

type FilterFunc

type FilterFunc func(tarName string) (relDest string, ok bool)

FilterFunc decides whether a tar entry should be extracted and, if so, the destination path (relative to destDir) to write it to.