sick

commit a6d6dd7c102aeed81bed2c7806880a5169072103
parent 2d6981d14b013ef2b573a349dc2bd41a560af285
Author: z3bra <willyatmailoodotorg>
Date:   Mon May  9 13:43:11 +12000

Implement signing in base64 format

The whole stream will be stored in a buffer and used for the signature.
Signature will be appended at the end of the stream in base64 format,
between two lines:

    -----BEGIN ED25519 SIGNATURE-----
    -----END ED25519 SIGNATURE-----

The base64 encoded lines are wrapped at char 76, as defined by posix.

Diffstat:
mkfile
 | 
2
+-
sick.c
 | 
56
+++++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 56 insertions(+), 2 deletions(-)
diff --git a/mkfile b/mkfile
@@ -2,7 +2,7 @@
 
 ED25519_SRC = `{find ed25519/src -name '*.c'}
 
-SRC = sick.c ${ED25519_SRC}
+SRC = sick.c base64.c ${ED25519_SRC}
 OBJ = ${SRC:%.c=%.o}
 
 sick: $OBJ
diff --git a/sick.c b/sick.c
@@ -5,8 +5,18 @@
 #include <string.h>
 
 #include "arg.h"
+#include "base64.h"
 #include "ed25519.h"
 
+#define SIGBEGIN "-----BEGIN ED25519 SIGNATURE-----\n"
+#define SIGEND "-----END ED25519 SIGNATURE-----\n"
+
+enum {
+	ACT_NONE,
+	ACT_SIGN,
+	ACT_CHCK
+};
+
 static void usage();
 static int createkeypair(const char *);
 
@@ -15,7 +25,7 @@ char *argv0;
 static void
 usage()
 {
-	fprintf(stderr, "usage: %s [-g ALIAS]\n", argv0);
+	fprintf(stderr, "usage: %s [-g ALIAS] [-f KEY] [-s [FILE..]]\n", argv0);
 	exit(EXIT_FAILURE);
 }
 
@@ -41,6 +51,7 @@ createkeypair(const char *alias)
 	ed25519_create_keypair(pub, priv, seed);
 
 	/* write private key to "<alias>.key" */
+	memset(fn, 0, PATH_MAX);
 	memcpy(fn, alias, len);
 	memcpy(fn+len, ".key", 4);
 	if ((fp = fopen(fn, "w")) == NULL) {
@@ -71,15 +82,58 @@ createkeypair(const char *alias)
 }
 
 int
+sign(FILE *fp, FILE *key)
+{
+	size_t len, siz = 0;
+	char tmp[64], *base64;
+	unsigned char sig[64], priv[64], *msg = NULL;
+
+	while((len = fread(tmp, 1, 64, fp)) > 0) {
+		siz += len;
+		msg = realloc(msg, siz);
+		memcpy(msg + siz - len, tmp, len);
+	}
+
+	fread(priv, 1, 64, key);
+	ed25519_sign(sig, msg, siz, priv);
+
+	len = base64_encode(&base64, sig, 64);
+	fwrite(msg, 1, siz, stdout);
+	fwrite(SIGBEGIN, 1, sizeof(SIGBEGIN), stdout);
+	base64_fold(stdout, base64, len, 0);
+	fwrite(SIGEND, 1, sizeof(SIGEND), stdout);
+
+	return 0;
+}
+
+int
 main(int argc, char *argv[])
 {
+	FILE *key = NULL, *fp = NULL;
+	int action = ACT_NONE;
+
 	ARGBEGIN{
+	case 'f':
+		key = fopen(EARGF(usage()), "r");
+		break;
 	case 'g':
 		createkeypair(EARGF(usage()));
 		break;
+	case 's':
+		action = ACT_SIGN;
+		break;
 	default:
 		usage();
 	}ARGEND;
 
+	if (!argc) {
+		fp = stdin;
+		switch (action) {
+		case ACT_SIGN:
+			sign(fp, key);
+			break;
+		}
+	}
+
 	return 0;
 }