extend stream capabilities

With this commit, both signing and verification get stream/file support
to read and write messages and signatures from and to files.

2 files changed, 115 insertions, 12 deletions

diff --git a/sign_input.go b/sign_input.go
index 6a264dc..c1ab9e0 100644
--- a/sign_input.go
+++ b/sign_input.go
@@ -4,10 +4,12 @@ import (
   "crypto"
   "crypto/rand"
   "crypto/sha256"
+  "encoding/base64"
   "errors"
   "flag"
   "fmt"
   "io"
+  "io/ioutil"
   "os"
 //  "crypto/ecdsa"
 //  "crypto/rsa"
@@ -16,16 +18,22 @@ import (
 type (
   SignInputFlags struct {
     Message        string // the message to sign
+    MessageStream  string // the message stream to sign
     PrivateKeyPath string // path to the private key
     Output         string // a path or stream to output the private key to
+    Format         string // the format of the output
 
     private_key crypto.Signer
     output_stream io.Writer // the output stream for the CSR
+    input_stream  io.Reader // the input stream to read the message from
   }
 )
 
 func sign_input() {
   flags := parse_sign_input_flags()
+  if flags.Message != "" && flags.MessageStream != "" {
+    crash_with_help(2, "Only message or message file can be signed!")
+  }
   flags.private_key = load_private_key(flags.PrivateKeyPath)
 
   output_stream, err := open_output_stream(flags.Output)
@@ -35,6 +43,15 @@ func sign_input() {
   flags.output_stream = output_stream
   defer output_stream.Close()
 
+  if flags.MessageStream != "" {
+    input_stream, err := open_input_stream(flags.MessageStream)
+    if err != nil {
+      crash_with_help(2, fmt.Sprintf("Error when opening stream %s: %s", flags.MessageStream, err))
+    }
+    flags.input_stream = input_stream
+    defer input_stream.Close()
+  }
+
   if err := create_signature(flags); err != nil {
     fmt.Fprintln(os.Stderr, "Error when creating signature", err)
     os.Exit(3)
@@ -45,15 +62,25 @@ func parse_sign_input_flags() SignInputFlags {
   flags := SignInputFlags{}
   fs := flag.NewFlagSet("sign-input", flag.ExitOnError)
   fs.StringVar(&flags.PrivateKeyPath, "private-key", "", "path to the private key file")
-  fs.StringVar(&flags.Output, "output", "STDOUT", "path where the generated signature should be stored")
+  fs.StringVar(&flags.Output, "output", "STDOUT", "path where the generated signature should be stored (STDOUT, STDERR, file)")
   fs.StringVar(&flags.Message, "message", "", "the message to sign")
+  fs.StringVar(&flags.MessageStream, "message-stream", "STDIN", "the path to the stream to sign (file, STDIN)")
+  fs.StringVar(&flags.Format, "format", "base64", "the output format (binary, base64)")
   fs.Parse(os.Args[2:])
 
   return flags
 }
 
 func create_signature(flags SignInputFlags) error {
-  message := []byte(flags.Message)
+  var message []byte
+  var err error
+
+  if flags.MessageStream != "" {
+    message, err = ioutil.ReadAll(flags.input_stream)
+    if err != nil { return err }
+  } else {
+    message = []byte(flags.Message)
+  }
   // compute sha256 of the message
   hash := sha256.New()
   length, _ := hash.Write(message)
@@ -66,6 +93,11 @@ func create_signature(flags SignInputFlags) error {
     nil,
   )
   if err != nil { return err }
-  flags.output_stream.Write(signature)
+  if flags.Format == "base64" {
+    flags.output_stream.Write([]byte(base64.StdEncoding.EncodeToString(signature)))
+  } else {
+    flags.output_stream.Write(signature)
+  }
+  flags.output_stream.Write([]byte("\n"))
   return nil
 }
diff --git a/verify_signature.go b/verify_signature.go
index 76020bb..b661e9a 100644
--- a/verify_signature.go
+++ b/verify_signature.go
@@ -6,19 +6,28 @@ import (
   "crypto/x509"
   "encoding/asn1"
   "encoding/pem"
+  "encoding/base64"
   "errors"
   "flag"
   "fmt"
+  "io"
   "io/ioutil"
   "math/big"
   "os"
+  "strings"
 )
 
 type (
   VerifySignatureFlags struct {
     Message        string // the message to sign
+    MessageStream  string // the path to the input stream
     PublicKeyPath  string // path to the private key
     Signature      string // a path or stream to output the private key to
+    SignatureStream string // read signature from an input stream
+    Format         string // the format of the signature
+
+    message_stream   io.Reader // the message stream
+    signature_stream io.Reader // the signature stream
   }
   // struct to load the signature into (which is basically two bigint in byte form)
   Signature struct {
@@ -28,16 +37,40 @@ type (
 
 func verify_signature() {
   flags := parse_verify_signature_flags()
+  if flags.SignatureStream == flags.MessageStream &&
+     ( flags.Message == "" && flags.Signature == "") {
+    crash_with_help(2, "Signature and Message stream can't be the same source!")
+  }
+
+  // open streams
+  if flags.Message == "" && flags.MessageStream != "" {
+    message_stream, err := open_input_stream(flags.MessageStream)
+    if err != nil {
+      crash_with_help(2, fmt.Sprintf("Error when opening stream %s: %s", flags.MessageStream, err))
+    }
+    defer message_stream.Close()
+    flags.message_stream = message_stream
+  }
+  if flags.Signature == "" && flags.SignatureStream != "" {
+    signature_stream, err := open_input_stream(flags.SignatureStream)
+    if err != nil {
+      crash_with_help(2, fmt.Sprintf("Error when opening stream %s: %s", flags.SignatureStream, err))
+    }
+    defer signature_stream.Close()
+    flags.signature_stream = signature_stream
+  }
+
   public_key, err := load_public_key_ecdsa(flags.PublicKeyPath)
   if err != nil {
     crash_with_help(2, fmt.Sprintf("Error when loading public key: %s", err))
   }
-  signature, err := load_signature(flags.Signature)
+  signature, err := load_signature(flags)
   if err != nil {
     crash_with_help(2, fmt.Sprintf("Error when loading the signature: %s", err))
   }
+  message, err := load_message(flags)
   hash := sha256.New()
-  hash.Write([]byte(flags.Message))
+  hash.Write([]byte(message))
 
   success := ecdsa.Verify(public_key, hash.Sum(nil), signature.R, signature.S)
   fmt.Println(success)
@@ -49,7 +82,10 @@ func parse_verify_signature_flags() VerifySignatureFlags {
   fs := flag.NewFlagSet("verify-signature", flag.ExitOnError)
   fs.StringVar(&flags.PublicKeyPath, "public-key", "", "path to the public key file")
   fs.StringVar(&flags.Signature, "signature", "", "path where the signature file can be found")
-  fs.StringVar(&flags.Message, "message", "", "the message to be validated")
+  fs.StringVar(&flags.SignatureStream, "signature-stream", "", "the path to the stream of the signature (file, STDIN)")
+  fs.StringVar(&flags.Format, "format", "auto", "the input format of the signature (auto, binary, base64)")
+  fs.StringVar(&flags.Message, "message", "", "the message to validate")
+  fs.StringVar(&flags.MessageStream, "message-stream", "STDIN", "the path to the stream to validate (file, STDIN)")
   fs.Parse(os.Args[2:])
 
   return flags
@@ -74,15 +110,50 @@ func load_public_key_ecdsa(path string) (*ecdsa.PublicKey, error) {
 }
 
 // parse the signature from asn1 file
-func load_signature(path string) (*Signature, error) {
-  signature_file, err := os.Open(path)
-  if err != nil { return nil, err }
-  signature_raw, err := ioutil.ReadAll(signature_file)
+func load_signature(flags VerifySignatureFlags) (*Signature, error) {
+  var signature_raw []byte
+  var err error
+  if flags.Message != "" {
+    signature_raw = []byte(flags.Message)
+  } else {
+    signature_raw, err = ioutil.ReadAll(flags.signature_stream)
+    if err != nil { return nil, err }
+  }
+
+  switch strings.ToLower(flags.Format) {
+  case "auto":
+    sig, err := load_signature_base64(signature_raw)
+    if err != nil {
+      sig, err = load_signature_binary(signature_raw)
+      if err != nil { return nil, err }
+      return sig, nil
+    }
+    return sig, nil
+  case "base64": return load_signature_base64(signature_raw)
+  case "binary": return load_signature_binary(signature_raw)
+  default: return nil, errors.New("Unknown format!")
+  }
+}
+
+// convert the signature from base64 into a signature
+func load_signature_base64(signature_raw []byte) (*Signature, error) {
+  asn1_sig, err := base64.StdEncoding.DecodeString(string(signature_raw))
   if err != nil { return nil, err }
-  signature_file.Close()
+  return load_signature_binary(asn1_sig)
+}
 
+// convert the signature from asn1 into a signature
+func load_signature_binary(signature_raw []byte) (*Signature, error) {
   var signature Signature
-  _, err = asn1.Unmarshal(signature_raw, &signature)
+  _, err := asn1.Unmarshal(signature_raw, &signature)
   if err != nil { return nil, err }
   return &signature, nil
 }
+
+// load the message from a stream or the parameter
+func load_message(flags VerifySignatureFlags) (string, error) {
+  if flags.Message != "" { return flags.Message, nil }
+  message, err := ioutil.ReadAll(flags.message_stream)
+  if err != nil { return "", err }
+  return string(message), nil
+}