Add node modules and compiled JavaScript from main (#54)

Co-authored-by: Oliver King <oking3@uncc.edu>

node_modules/jose/lib/help/ecdsa_signatures.js

@@ -0,0 +1,180 @@
+const MAX_OCTET = 0x80
+const CLASS_UNIVERSAL = 0
+const PRIMITIVE_BIT = 0x20
+const TAG_SEQ = 0x10
+const TAG_INT = 0x02
+const ENCODED_TAG_SEQ = (TAG_SEQ | PRIMITIVE_BIT) | (CLASS_UNIVERSAL << 6)
+const ENCODED_TAG_INT = TAG_INT | (CLASS_UNIVERSAL << 6)
+
+const getParamSize = keySize => ((keySize / 8) | 0) + (keySize % 8 === 0 ? 0 : 1)
+
+const paramBytesForAlg = {
+  ES256: getParamSize(256),
+  ES256K: getParamSize(256),
+  ES384: getParamSize(384),
+  ES512: getParamSize(521)
+}
+
+const countPadding = (buf, start, stop) => {
+  let padding = 0
+  while (start + padding < stop && buf[start + padding] === 0) {
+    ++padding
+  }
+
+  const needsSign = buf[start + padding] >= MAX_OCTET
+  if (needsSign) {
+    --padding
+  }
+
+  return padding
+}
+
+module.exports.derToJose = (signature, alg) => {
+  if (!Buffer.isBuffer(signature)) {
+    throw new TypeError('ECDSA signature must be a Buffer')
+  }
+
+  if (!paramBytesForAlg[alg]) {
+    throw new Error(`Unknown algorithm "${alg}"`)
+  }
+
+  const paramBytes = paramBytesForAlg[alg]
+
+  // the DER encoded param should at most be the param size, plus a padding
+  // zero, since due to being a signed integer
+  const maxEncodedParamLength = paramBytes + 1
+
+  const inputLength = signature.length
+
+  let offset = 0
+  if (signature[offset++] !== ENCODED_TAG_SEQ) {
+    throw new Error('Could not find expected "seq"')
+  }
+
+  let seqLength = signature[offset++]
+  if (seqLength === (MAX_OCTET | 1)) {
+    seqLength = signature[offset++]
+  }
+
+  if (inputLength - offset < seqLength) {
+    throw new Error(`"seq" specified length of ${seqLength}", only ${inputLength - offset}" remaining`)
+  }
+
+  if (signature[offset++] !== ENCODED_TAG_INT) {
+    throw new Error('Could not find expected "int" for "r"')
+  }
+
+  const rLength = signature[offset++]
+
+  if (inputLength - offset - 2 < rLength) {
+    throw new Error(`"r" specified length of "${rLength}", only "${inputLength - offset - 2}" available`)
+  }
+
+  if (maxEncodedParamLength < rLength) {
+    throw new Error(`"r" specified length of "${rLength}", max of "${maxEncodedParamLength}" is acceptable`)
+  }
+
+  const rOffset = offset
+  offset += rLength
+
+  if (signature[offset++] !== ENCODED_TAG_INT) {
+    throw new Error('Could not find expected "int" for "s"')
+  }
+
+  const sLength = signature[offset++]
+
+  if (inputLength - offset !== sLength) {
+    throw new Error(`"s" specified length of "${sLength}", expected "${inputLength - offset}"`)
+  }
+
+  if (maxEncodedParamLength < sLength) {
+    throw new Error(`"s" specified length of "${sLength}", max of "${maxEncodedParamLength}" is acceptable`)
+  }
+
+  const sOffset = offset
+  offset += sLength
+
+  if (offset !== inputLength) {
+    throw new Error(`Expected to consume entire buffer, but "${inputLength - offset}" bytes remain`)
+  }
+
+  const rPadding = paramBytes - rLength
+
+  const sPadding = paramBytes - sLength
+
+  const dst = Buffer.allocUnsafe(rPadding + rLength + sPadding + sLength)
+
+  for (offset = 0; offset < rPadding; ++offset) {
+    dst[offset] = 0
+  }
+  signature.copy(dst, offset, rOffset + Math.max(-rPadding, 0), rOffset + rLength)
+
+  offset = paramBytes
+
+  for (const o = offset; offset < o + sPadding; ++offset) {
+    dst[offset] = 0
+  }
+  signature.copy(dst, offset, sOffset + Math.max(-sPadding, 0), sOffset + sLength)
+
+  return dst
+}
+
+module.exports.joseToDer = (signature, alg) => {
+  if (!Buffer.isBuffer(signature)) {
+    throw new TypeError('ECDSA signature must be a Buffer')
+  }
+
+  if (!paramBytesForAlg[alg]) {
+    throw new TypeError(`Unknown algorithm "${alg}"`)
+  }
+
+  const paramBytes = paramBytesForAlg[alg]
+
+  const signatureBytes = signature.length
+  if (signatureBytes !== paramBytes * 2) {
+    throw new Error(`"${alg}" signatures must be "${paramBytes * 2}" bytes, saw "${signatureBytes}"`)
+  }
+
+  const rPadding = countPadding(signature, 0, paramBytes)
+  const sPadding = countPadding(signature, paramBytes, signature.length)
+  const rLength = paramBytes - rPadding
+  const sLength = paramBytes - sPadding
+
+  const rsBytes = 1 + 1 + rLength + 1 + 1 + sLength
+
+  const shortLength = rsBytes < MAX_OCTET
+
+  const dst = Buffer.allocUnsafe((shortLength ? 2 : 3) + rsBytes)
+
+  let offset = 0
+  dst[offset++] = ENCODED_TAG_SEQ
+  if (shortLength) {
+    // Bit 8 has value "0"
+    // bits 7-1 give the length.
+    dst[offset++] = rsBytes
+  } else {
+    // Bit 8 of first octet has value "1"
+    // bits 7-1 give the number of additional length octets.
+    dst[offset++] = MAX_OCTET	| 1 // eslint-disable-line no-tabs
+    // length, base 256
+    dst[offset++] = rsBytes & 0xff
+  }
+  dst[offset++] = ENCODED_TAG_INT
+  dst[offset++] = rLength
+  if (rPadding < 0) {
+    dst[offset++] = 0
+    offset += signature.copy(dst, offset, 0, paramBytes)
+  } else {
+    offset += signature.copy(dst, offset, rPadding, paramBytes)
+  }
+  dst[offset++] = ENCODED_TAG_INT
+  dst[offset++] = sLength
+  if (sPadding < 0) {
+    dst[offset++] = 0
+    signature.copy(dst, offset, paramBytes)
+  } else {
+    signature.copy(dst, offset, paramBytes + sPadding)
+  }
+
+  return dst
+}