1 files changed, 216 insertions, 0 deletions
diff --git a/vespajlib/src/main/java/com/yahoo/compress/ArchiveStreamReader.java b/vespajlib/src/main/java/com/yahoo/compress/ArchiveStreamReader.java
new file mode 100644
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+++ b/vespajlib/src/main/java/com/yahoo/compress/ArchiveStreamReader.java
@@ -0,0 +1,216 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.compress;
+
+import com.yahoo.path.Path;
+import com.yahoo.yolean.Exceptions;
+import org.apache.commons.compress.archivers.ArchiveEntry;
+import org.apache.commons.compress.archivers.ArchiveInputStream;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
+import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
+import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
+import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.UncheckedIOException;
+import java.util.Objects;
+import java.util.OptionalLong;
+import java.util.function.Predicate;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * Helper class for safely reading files from a compressed archive.
+ *
+ * @author mpolden
+ */
+public class ArchiveStreamReader implements AutoCloseable {
+
+    private final ArchiveInputStream archiveInputStream;
+    private final Options options;
+
+    private long totalRead = 0;
+    private long entriesRead = 0;
+
+    private ArchiveStreamReader(ArchiveInputStream archiveInputStream, Options options) {
+        this.archiveInputStream = Objects.requireNonNull(archiveInputStream);
+        this.options = Objects.requireNonNull(options);
+    }
+
+    /** Create reader for an inputStream containing a tar.gz file */
+    public static ArchiveStreamReader ofTarGzip(InputStream inputStream, Options options) {
+        return new ArchiveStreamReader(new TarArchiveInputStream(Exceptions.uncheck(() -> new GZIPInputStream(inputStream))), options);
+    }
+
+    /** Create reader for an inputStream containing a ZIP file */
+    public static ArchiveStreamReader ofZip(InputStream inputStream, Options options) {
+        return new ArchiveStreamReader(new ZipArchiveInputStream(inputStream), options);
+    }
+
+    /**
+     * Read the next file in this archive and write it to given outputStream. Returns information about the read archive
+     * file, or null if there are no more files to read.
+     */
+    public ArchiveFile readNextTo(OutputStream outputStream) {
+        ArchiveEntry entry;
+        try {
+            while ((entry = archiveInputStream.getNextEntry()) != null) {
+                Path path = Path.fromString(requireNormalized(entry.getName(), options.allowDotSegment));
+                if (isSymlink(entry)) throw new IllegalArgumentException("Archive entry " + path + " is a symbolic link, which is unsupported");
+                if (entry.isDirectory()) continue;
+                if (!options.pathPredicate.test(path.toString())) continue;
+                if (++entriesRead > options.maxEntries) throw new IllegalArgumentException("Attempted to read more entries than entry limit of " + options.maxEntries);
+
+                long size = 0;
+                byte[] buffer = new byte[2048];
+                int read;
+                while ((read = archiveInputStream.read(buffer)) != -1) {
+                    totalRead += read;
+                    size += read;
+                    if (totalRead > options.maxSize) throw new IllegalArgumentException("Total size of archive exceeds size limit of " + options.maxSize + " bytes");
+                    if (read > options.maxEntrySize) {
+                        if (!options.truncateEntry) throw new IllegalArgumentException("Size of entry " + path + " exceeded entry size limit of " + options.maxEntrySize + " bytes");
+                    } else {
+                        outputStream.write(buffer, 0, read);
+                    }
+                }
+                return new ArchiveFile(path, crc32(entry), size);
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+        return null;
+    }
+
+    @Override
+    public void close() {
+        Exceptions.uncheck(archiveInputStream::close);
+    }
+
+    /** Information about a file extracted from a compressed archive */
+    public static class ArchiveFile {
+
+        private final Path path;
+        private final OptionalLong crc32;
+        private final long size;
+
+        public ArchiveFile(Path name, OptionalLong crc32, long size) {
+            this.path = Objects.requireNonNull(name);
+            this.crc32 = Objects.requireNonNull(crc32);
+            if (crc32.isPresent()) {
+                requireNonNegative("crc32", crc32.getAsLong());
+            }
+            this.size = requireNonNegative("size", size);
+        }
+
+        /** The path of this file inside its containing archive */
+        public Path path() {
+            return path;
+        }
+
+        /** The CRC-32 checksum of this file, if any */
+        public OptionalLong crc32() {
+            return crc32;
+        }
+
+        /** The decompressed size of this file */
+        public long size() {
+            return size;
+        }
+
+    }
+
+    /** Get the CRC-32 checksum of given archive entry, if any */
+    private static OptionalLong crc32(ArchiveEntry entry) {
+        long crc32 = -1;
+        if (entry instanceof ZipArchiveEntry) {
+            crc32 = ((ZipArchiveEntry) entry).getCrc();
+        }
+        return crc32 > -1 ? OptionalLong.of(crc32) : OptionalLong.empty();
+    }
+
+    private static boolean isSymlink(ArchiveEntry entry) {
+        // Symlinks inside ZIP files are not part of the ZIP spec and are only supported by some implementations, such
+        // as Info-ZIP.
+        //
+        // Commons Compress only has limited support for symlinks as they are only detected when the ZIP file is read
+        // through org.apache.commons.compress.archivers.zip.ZipFile. This is not the case in this class, because it must
+        // support reading ZIP files from generic input streams. The check below thus always returns false.
+        if (entry instanceof ZipArchiveEntry) return ((ZipArchiveEntry) entry).isUnixSymlink();
+        if (entry instanceof TarArchiveEntry) return ((TarArchiveEntry) entry).isSymbolicLink();
+        throw new IllegalArgumentException("Unsupported archive entry " + entry.getClass().getSimpleName() + ", cannot check for symbolic link");
+    }
+
+    private static String requireNormalized(String name, boolean allowDotSegment) {
+        for (var part : name.split("/")) {
+            if (part.isEmpty() || (!allowDotSegment && part.equals(".")) || part.equals("..")) {
+                throw new IllegalArgumentException("Unexpected non-normalized path found in zip content: '" + name + "'");
+            }
+        }
+        return name;
+    }
+
+    private static long requireNonNegative(String field, long n) {
+        if (n < 0) throw new IllegalArgumentException(field + " cannot be negative, got " + n);
+        return n;
+    }
+
+    /** Options for reading entries of an archive */
+    public static class Options {
+
+        private long maxSize = 8 * (long) Math.pow(1024, 3); // 8 GB
+        private long maxEntrySize = Long.MAX_VALUE;
+        private long maxEntries = Long.MAX_VALUE;
+        private boolean truncateEntry = false;
+        private boolean allowDotSegment = false;
+        private Predicate<String> pathPredicate = (path) -> true;
+
+        private Options() {}
+
+        /** Returns the standard set of read options */
+        public static Options standard() {
+            return new Options();
+        }
+
+        /** Set the maximum total size of decompressed entries. Default is 8 GB */
+        public Options maxSize(long size) {
+            this.maxSize = requireNonNegative("size", size);
+            return this;
+        }
+
+        /** Set the maximum size a decompressed entry. Default is no limit */
+        public Options maxEntrySize(long size) {
+            this.maxEntrySize = requireNonNegative("size", size);
+            return this;
+        }
+
+        /** Set the maximum number of entries to decompress. Default is no limit */
+        public Options maxEntries(long count) {
+            this.maxEntries = requireNonNegative("count", count);
+            return this;
+        }
+
+        /**
+         * Set whether to truncate the content of an entry exceeding the configured size limit, instead of throwing.
+         * Default is to throw.
+         */
+        public Options truncateEntry(boolean truncate) {
+            this.truncateEntry = truncate;
+            return this;
+        }
+
+        /** Set a predicate that an entry path must match in order to be extracted. Default is to extract all entries */
+        public Options pathPredicate(Predicate<String> predicate) {
+            this.pathPredicate = predicate;
+            return this;
+        }
+
+        /** Set whether to allow single-dot segments in entry paths. Default is false */
+        public Options allowDotSegment(boolean allow) {
+            this.allowDotSegment = allow;
+            return this;
+        }
+
+    }
+
+}