Add support for Fulcio and Rekor, and --sign-by-sigstore=param-file

(skopeo copy) and (skopeo sync) now support --sign-by-sigstore=param-file,
using the containers-sigstore-signing-params.yaml(5) file format.

That notably adds support for Fulcio and Rekor signing.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/segmentio/ksuid/uint128.go

@@ -0,0 +1,141 @@
+package ksuid
+
+import "fmt"
+
+// uint128 represents an unsigned 128 bits little endian integer.
+type uint128 [2]uint64
+
+func uint128Payload(ksuid KSUID) uint128 {
+	return makeUint128FromPayload(ksuid[timestampLengthInBytes:])
+}
+
+func makeUint128(high uint64, low uint64) uint128 {
+	return uint128{low, high}
+}
+
+func makeUint128FromPayload(payload []byte) uint128 {
+	return uint128{
+		// low
+		uint64(payload[8])<<56 |
+			uint64(payload[9])<<48 |
+			uint64(payload[10])<<40 |
+			uint64(payload[11])<<32 |
+			uint64(payload[12])<<24 |
+			uint64(payload[13])<<16 |
+			uint64(payload[14])<<8 |
+			uint64(payload[15]),
+		// high
+		uint64(payload[0])<<56 |
+			uint64(payload[1])<<48 |
+			uint64(payload[2])<<40 |
+			uint64(payload[3])<<32 |
+			uint64(payload[4])<<24 |
+			uint64(payload[5])<<16 |
+			uint64(payload[6])<<8 |
+			uint64(payload[7]),
+	}
+}
+
+func (v uint128) ksuid(timestamp uint32) KSUID {
+	return KSUID{
+		// time
+		byte(timestamp >> 24),
+		byte(timestamp >> 16),
+		byte(timestamp >> 8),
+		byte(timestamp),
+
+		// high
+		byte(v[1] >> 56),
+		byte(v[1] >> 48),
+		byte(v[1] >> 40),
+		byte(v[1] >> 32),
+		byte(v[1] >> 24),
+		byte(v[1] >> 16),
+		byte(v[1] >> 8),
+		byte(v[1]),
+
+		// low
+		byte(v[0] >> 56),
+		byte(v[0] >> 48),
+		byte(v[0] >> 40),
+		byte(v[0] >> 32),
+		byte(v[0] >> 24),
+		byte(v[0] >> 16),
+		byte(v[0] >> 8),
+		byte(v[0]),
+	}
+}
+
+func (v uint128) bytes() [16]byte {
+	return [16]byte{
+		// high
+		byte(v[1] >> 56),
+		byte(v[1] >> 48),
+		byte(v[1] >> 40),
+		byte(v[1] >> 32),
+		byte(v[1] >> 24),
+		byte(v[1] >> 16),
+		byte(v[1] >> 8),
+		byte(v[1]),
+
+		// low
+		byte(v[0] >> 56),
+		byte(v[0] >> 48),
+		byte(v[0] >> 40),
+		byte(v[0] >> 32),
+		byte(v[0] >> 24),
+		byte(v[0] >> 16),
+		byte(v[0] >> 8),
+		byte(v[0]),
+	}
+}
+
+func (v uint128) String() string {
+	return fmt.Sprintf("0x%016X%016X", v[0], v[1])
+}
+
+const wordBitSize = 64
+
+func cmp128(x, y uint128) int {
+	if x[1] < y[1] {
+		return -1
+	}
+	if x[1] > y[1] {
+		return 1
+	}
+	if x[0] < y[0] {
+		return -1
+	}
+	if x[0] > y[0] {
+		return 1
+	}
+	return 0
+}
+
+func add128(x, y uint128) (z uint128) {
+	x0 := x[0]
+	y0 := y[0]
+	z0 := x0 + y0
+	z[0] = z0
+
+	c := (x0&y0 | (x0|y0)&^z0) >> (wordBitSize - 1)
+
+	z[1] = x[1] + y[1] + c
+	return
+}
+
+func sub128(x, y uint128) (z uint128) {
+	x0 := x[0]
+	y0 := y[0]
+	z0 := x0 - y0
+	z[0] = z0
+
+	c := (y0&^x0 | (y0|^x0)&z0) >> (wordBitSize - 1)
+
+	z[1] = x[1] - y[1] - c
+	return
+}
+
+func incr128(x uint128) uint128 {
+	return add128(x, uint128{1, 0})
+}