Dump: add output format tar and output to stdout (#10376)

* Dump: Use mholt/archive/v3 to support tar including many compressions

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Allow dump output to stdout

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Fixed bug present since #6677 where SessionConfig.Provider is never "file"

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never pack RepoRootPath, LFS.ContentPath and LogRootPath when they are below AppDataPath

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: also dump LFS (fixes #10058)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never dump CustomPath if CustomPath is a subdir of or equal to AppDataPath (fixes #10365)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Use log.Info instead of fmt.Fprintf

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* import ordering

* make fmt

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Matti R <matti@mdranta.net>

vendor/github.com/nwaples/rardecode/decrypt_reader.go

@@ -0,0 +1,126 @@
+package rardecode
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"io"
+)
+
+// cipherBlockReader implements Block Mode decryption of an io.Reader object.
+type cipherBlockReader struct {
+	r      io.Reader
+	mode   cipher.BlockMode
+	inbuf  []byte // input buffer for partial data block
+	outbuf []byte // output buffer used when output slice < block size
+	n      int    // bytes read from outbuf
+	err    error
+}
+
+// read reads and decrypts one or more input blocks into p.
+// len(p) must be >= cipher block size.
+func (cr *cipherBlockReader) read(p []byte) (n int, err error) {
+	bs := cr.mode.BlockSize()
+	// round p down to a multiple of the block size
+	l := len(p) - len(p)%bs
+	p = p[:l]
+
+	l = len(cr.inbuf)
+	if l > 0 {
+		// copy any buffered input into p
+		copy(p, cr.inbuf)
+		cr.inbuf = cr.inbuf[:0]
+	}
+	// read data for at least one block
+	n, err = io.ReadAtLeast(cr.r, p[l:], bs-l)
+	n += l
+	p = p[:n]
+
+	l = n % bs
+	// check if p is a multiple of the cipher block size
+	if l > 0 {
+		n -= l
+		// save trailing partial block to process later
+		cr.inbuf = append(cr.inbuf, p[n:]...)
+		p = p[:n]
+	}
+
+	if err != nil {
+		if err == io.ErrUnexpectedEOF || err == io.ErrShortBuffer {
+			// ignore trailing bytes < block size length
+			err = io.EOF
+		}
+		return 0, err
+	}
+	cr.mode.CryptBlocks(p, p) // decrypt block(s)
+	return n, nil
+}
+
+// Read reads and decrypts data into p.
+// If the input is not a multiple of the cipher block size,
+// the trailing bytes will be ignored.
+func (cr *cipherBlockReader) Read(p []byte) (n int, err error) {
+	for {
+		if cr.n < len(cr.outbuf) {
+			// return buffered output
+			n = copy(p, cr.outbuf[cr.n:])
+			cr.n += n
+			return n, nil
+		}
+		if cr.err != nil {
+			err = cr.err
+			cr.err = nil
+			return 0, err
+		}
+		if len(p) >= cap(cr.outbuf) {
+			break
+		}
+		// p is not large enough to process a block, use outbuf instead
+		n, cr.err = cr.read(cr.outbuf[:cap(cr.outbuf)])
+		cr.outbuf = cr.outbuf[:n]
+		cr.n = 0
+	}
+	// read blocks into p
+	return cr.read(p)
+}
+
+// ReadByte returns the next decrypted byte.
+func (cr *cipherBlockReader) ReadByte() (byte, error) {
+	for {
+		if cr.n < len(cr.outbuf) {
+			c := cr.outbuf[cr.n]
+			cr.n++
+			return c, nil
+		}
+		if cr.err != nil {
+			err := cr.err
+			cr.err = nil
+			return 0, err
+		}
+		// refill outbuf
+		var n int
+		n, cr.err = cr.read(cr.outbuf[:cap(cr.outbuf)])
+		cr.outbuf = cr.outbuf[:n]
+		cr.n = 0
+	}
+}
+
+// newCipherBlockReader returns a cipherBlockReader that decrypts the given io.Reader using
+// the provided block mode cipher.
+func newCipherBlockReader(r io.Reader, mode cipher.BlockMode) *cipherBlockReader {
+	cr := &cipherBlockReader{r: r, mode: mode}
+	cr.outbuf = make([]byte, 0, mode.BlockSize())
+	cr.inbuf = make([]byte, 0, mode.BlockSize())
+	return cr
+}
+
+// newAesDecryptReader returns a cipherBlockReader that decrypts input from a given io.Reader using AES.
+// It will panic if the provided key is invalid.
+func newAesDecryptReader(r io.Reader, key, iv []byte) *cipherBlockReader {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+	mode := cipher.NewCBCDecrypter(block, iv)
+
+	return newCipherBlockReader(r, mode)
+}