From: Eugene Crosser <crosser@average.org>
Date: Sat, 30 Nov 2013 22:05:43 +0000 (+0400)
Subject: wip on struct authobj interface
X-Git-Url: http://www.average.org/gitweb/?p=pam_pcsc_cr.git;a=commitdiff_plain;h=67023db2952f4c3ec55a247dec401366f6b92e99

wip on struct authobj interface
---

diff --git a/README_CR b/README_CR
index a55e916..96e24f5 100644
--- a/README_CR
+++ b/README_CR
@@ -7,13 +7,18 @@ user record:
 		data:
 			shared-secret
 			payload
-			crc
+			sha1(
+				shared-secret
+				payload
+			)
 		key:
 			hmac-sha1:
 				data:
-					userid
-					password
-					seqno
+					sha1(
+						userid
+						password
+						seqno
+					)
 				key:
 					shared-secret
 
diff --git a/authobj.c b/authobj.c
index d2b6b7d..eefc92b 100644
--- a/authobj.c
+++ b/authobj.c
@@ -7,70 +7,125 @@
 #include "serial.h"
 #include "crypto.h"
 #include "authobj.h"
+#include "pcsc_cr.h"
 
-int make_challenge(const char *id, const char *pass, const char *nonce,
-		unsigned char *challenge, int *challengesize)
+struct _hash_obj {
+	const char *err;
+	unsigned char hash[HASHSIZE];
+};
+
+static struct _hash_obj
+make_challenge(const char *uid, const char *pass, const char *nonce)
 {
+	struct _hash_obj ho = {0};
+	unsigned long rc;
 	serializer_t srl;
+	int datasize = strlen(uid) + strlen(pass) + strlen(nonce) +
+			4 * sizeof(short);
+	unsigned char *data = alloca(datasize);
+	int hashsize = sizeof(ho.hash);
 
-	serial_init(&srl, challenge, *challengesize);
-	if (serial_put(&srl, id, strlen(id)) != strlen(id))
-		return aoe_serial;
-	if (serial_put(&srl, pass, strlen(pass)) != strlen(pass))
-		return aoe_serial;
-	if (serial_put(&srl, nonce, strlen(nonce)) != strlen(nonce))
-		return aoe_serial;
-	if (serial_put(&srl, NULL, 0) != 0)
-		return aoe_serial;
-	*challengesize = serial_size(&srl);
-	return 0;
+	serial_init(&srl, data, datasize);
+	if (serial_put(&srl, uid, strlen(uid)) != strlen(uid)) {
+		ho.err = "challenge: serialization of uid failed";
+	} else if (serial_put(&srl, pass, strlen(pass)) != strlen(pass)) {
+		ho.err = "challenge: serialization of pass failed";
+	} else if (serial_put(&srl, nonce, strlen(nonce)) != strlen(nonce)) {
+		ho.err = "challenge: serialization of nonce failed";
+	} else if (serial_put(&srl, NULL, 0) != 0) {
+		ho.err = "challenge: serialization of terminator failed";
+	}
+	if (!ho.err) {
+		if ((rc = hash(data, serial_size(&srl), &ho.hash, &hashsize))) {
+			ho.err = crypto_errstr(rc);
+		} else if (hashsize != sizeof(ho.hash)) {
+			ho.err = "challenge: hash size is wrong";
+		}
+	}
+	memset(data, 0, datasize);
+	return ho;
+}
+
+static struct _hash_obj
+make_key(const unsigned char *challenge, const int challengesize,
+	const unsigned char *secret, const int secsize)
+{
+	struct _hash_obj ho = {0};
+	unsigned long rc;
+	int keysize = sizeof(ho.hash);
+
+	if ((rc = hmac(secret, secsize, challenge, challengesize,
+			&ho.hash, &keysize))) {
+		ho.err = crypto_errstr(rc);
+	} else if (keysize != sizeof(ho.hash)) {
+		ho.err = "make_key: hash size is wrong";
+	}
+	return ho;
 }
 
-int make_authobj(const char *id, const char *pass, const char *nonce,
+static struct _hash_obj
+fetch_key(const unsigned char *challenge, const int challengesize)
+{
+	struct _hash_obj ho = {0};
+	int rc;
+	int keysize = sizeof(ho.hash);
+
+	if ((rc = pcsc_cr(challenge, challengesize, ho.hash, &keysize))) {
+		ho.err = pcsc_errstr(rc);
+	}
+	return ho;
+}
+
+static struct _auth_obj
+make_authobj(const unsigned char *key, const int keysize,
 		const unsigned char *secret, const int secsize,
-		const unsigned char *payload, const int paysize,
-		unsigned char *buffer, int *bufsize)
+		const unsigned char *payload, const int paysize)
 {
+	struct _auth_obj ao = {0};
+	unsigned long rc;
 	unsigned char *data;
 	int datasize;
 	unsigned char datahash[HASHSIZE];
 	int datahashsize = HASHSIZE;
-	unsigned char *challenge;
-	int challengesize;
-	unsigned char key[HASHSIZE];
-	int keysize = HASHSIZE;
 	serializer_t srl;
 
 	datasize = ((secsize + paysize + HASHSIZE + 4 * sizeof(short) - 1) /
 			CBLKSIZE + 1) * CBLKSIZE;
 	data = alloca(datasize);
 	serial_init(&srl, data, datasize);
-	if (serial_put(&srl, secret, secsize) != secsize) return aoe_serial;
-	if (serial_put(&srl, payload, paysize) != paysize) return aoe_serial;
-	if (hash(data, serial_size(&srl), datahash, &datahashsize))
-		return aoe_size;
-	if (serial_put(&srl, datahash, datahashsize) != datahashsize)
-		return aoe_serial;
-	if (serial_put(&srl, NULL, 0) != 0) return aoe_serial;
-	datasize = ((serial_size(&srl) -1) / CBLKSIZE + 1) * CBLKSIZE;
-
-	challengesize = ((strlen(id) + strlen(pass) + strlen(nonce) +
-			4 * sizeof(short) - 1) / CBLKSIZE + 1) * CBLKSIZE;
-	challenge = alloca(challengesize);
-	if (make_challenge(id, pass, nonce, challenge, &challengesize))
-		return aoe_serial;
-
-	if (hmac(secret, secsize, challenge, challengesize,
-		key, &keysize)) return aoe_crypt;
-
-	if (*bufsize < datasize) return aoe_size;
-	if (encrypt(key, CBLKSIZE, data, buffer, datasize)) return aoe_crypt;
-	*bufsize = datasize;
+	if (serial_put(&srl, secret, secsize) != secsize) {
+		ao.err = "authobj: serialization of secret failed";
+	} else if (serial_put(&srl, payload, paysize) != paysize) {
+		ao.err = "authobj: serialization of payload failed";
+	} else if ((rc = hash(data, serial_size(&srl),
+				datahash, &datahashsize))) {
+		ao.err = crypto_errstr(rc);
+	} else if (serial_put(&srl, datahash, datahashsize) != datahashsize) {
+		ao.err = "authobj: serialization of hash failed";
+	} else if (serial_put(&srl, NULL, 0) != 0) {
+		ao.err = "authobj: serialization of terminator failed";
+	}
 
-	return 0;
+	if (!ao.err) {
+		unsigned long lrc;
+		int osize = ((serial_size(&srl) -1) / CBLKSIZE + 1) * CBLKSIZE;
+
+		if ((ao.buffer = malloc(osize)) == NULL) {
+			ao.err = "authobj: malloc failed";
+		} else if ((lrc = encrypt(key, CBLKSIZE, data,
+					ao.buffer, osize))) {
+			ao.err = crypto_errstr(lrc);
+		} else {
+			ao.authobj = ao.buffer;
+			ao.authsize = osize;
+		}
+	}
+
+	memset(data, 0, datasize);
+	return ao;
 }
 
-int parse_authobj(const unsigned char *key, const int keysize,
+static int parse_authobj(const unsigned char *key, const int keysize,
 		const unsigned char *buffer, const int bufsize,
 		unsigned char *secret, int *secsize,
 		unsigned char *payload, int *paysize)
@@ -85,20 +140,90 @@ int parse_authobj(const unsigned char *key, const int keysize,
 	int theirhashsize = HASHSIZE;
 
 	if (decrypt(key, CBLKSIZE, buffer, data, datasize))
-		return aoe_crypt;
+		return 1;
 	serial_init(&srl, data, datasize);
 	tsize = *secsize;
 	*secsize = serial_get(&srl, secret, tsize);
-	if (*secsize > tsize || *secsize <= 0) return aoe_serial;
+	if (*secsize > tsize || *secsize <= 0) return 1;
 	tsize = *paysize;
 	*paysize = serial_get(&srl, payload, tsize);
-	if (*paysize > tsize || *paysize <= 0) return aoe_serial;
+	if (*paysize > tsize || *paysize <= 0) return 1;
 	if (hash(data, serial_size(&srl), myhash, &myhashsize))
-		return aoe_crypt;
+		return 1;
 	theirhashsize = serial_get(&srl, theirhash, theirhashsize);
-	if (theirhashsize != HASHSIZE) return aoe_data;
+	if (theirhashsize != HASHSIZE) return 1;
 	if ((myhashsize != theirhashsize) ||
 	    memcmp(myhash, theirhash, myhashsize))
-		return aoe_data;
+		return 1;
 	return 0;
 }
+
+struct _auth_obj new_authobj(const char *userid, const char *password,
+				const char *nonce,
+			const unsigned char *secret, const int secsize,
+			const unsigned char *payload, const int paysize)
+{
+	struct _auth_obj ao = {0};
+	struct _hash_obj ho_chal, ho_key;
+
+	ho_chal = make_challenge(userid, password, nonce);
+	if (ho_chal.err) {
+		ao.err = ho_chal.err;
+		return ao;
+	}
+	ho_key = make_key(ho_chal.hash, sizeof(ho_chal.hash), secret, secsize);
+	if (ho_key.err) {
+		ao.err = ho_key.err;
+		return ao;
+	}
+	ao = make_authobj(ho_key.hash, sizeof(ho_key.hash),
+			secret, secsize, payload, paysize);
+	memset(&ho_chal, 0, sizeof(ho_chal));
+	memset(&ho_key, 0, sizeof(ho_key));
+	return ao;
+}
+
+struct _auth_obj verify_authobj(const char *userid, const char *password,
+				const char *oldnonce, const char *newnonce,
+			const unsigned char *authobj, const int authsize)
+{
+	struct _auth_obj ao = {0};
+	struct _hash_obj ho_chal, ho_key;
+
+	ho_chal = make_challenge(userid, password, oldnonce);
+	if (ho_chal.err) {
+		ao.err = ho_chal.err;
+		return ao;
+	}
+	ho_key = fetch_key(ho_chal.hash, sizeof(ho_chal.hash));
+	if (ho_key.err) {
+		ao.err = ho_key.err;
+		return ao;
+	}
+	memset(&ho_chal, 0, sizeof(ho_chal));
+	memset(&ho_key, 0, sizeof(ho_key));
+	return ao;
+}
+
+struct _auth_obj reload_authobj(const char *userid, const char *password,
+				const char *oldnonce, const char *newnonce,
+			const unsigned char *authobj, const int authsize,
+			const unsigned char *payload, const int paysize)
+{
+	struct _auth_obj ao = {0};
+	struct _hash_obj ho_chal, ho_key;
+
+	ho_chal = make_challenge(userid, password, oldnonce);
+	if (ho_chal.err) {
+		ao.err = ho_chal.err;
+		return ao;
+	}
+	ho_key = fetch_key(ho_chal.hash, sizeof(ho_chal.hash));
+	if (ho_key.err) {
+		ao.err = ho_key.err;
+		return ao;
+	}
+	memset(&ho_chal, 0, sizeof(ho_chal));
+	memset(&ho_key, 0, sizeof(ho_key));
+	return ao;
+}
diff --git a/authobj.h b/authobj.h
index cc5baed..b075654 100644
--- a/authobj.h
+++ b/authobj.h
@@ -1,17 +1,30 @@
 #ifndef _AUTHOBJ_H
 #define _AUTHOBJ_H
 
-enum aobj_err {aoe_serial, aoe_size, aoe_crypt, aoe_data};
+struct _auth_obj {
+	unsigned char *buffer;	/* to be free()'d if not NULL */
+	const char *err;	/* non-NULL if failed */
+	unsigned char *authobj;
+	int authsize;
+	unsigned char *payload;
+	int paylsize;
+};
 
-int make_challenge(const char *id, const char *pass, const char *nonce,
-		unsigned char *challenge, int *challengesize);
-int make_authobj(const char *id, const char *pass, const char *nonce,
-		const unsigned char *secret, const int secsize,
-		const unsigned char *payload, const int paysize,
-		unsigned char *buffer, int *bufsize);
-int parse_authobj(const unsigned char *key, const int keysize,
-		const unsigned char *buffer, const int bufsize,
-		unsigned char *secret, int *secsize,
-		unsigned char *payload, int *paysize);
+/* Construct new authobj from the given secret and other data */
+struct _auth_obj new_authobj(const char *userid, const char *password,
+				const char *nonce,
+			const unsigned char *secret, const int secsize,
+			const unsigned char *payload, const int paysize);
+
+/* Unwrap old authobj, extract payload, construct new one with newnonce */
+struct _auth_obj verify_authobj(const char *userid, const char *password,
+				const char *oldnonce, const char *newnonce,
+			const unsigned char *authobj, const int authsize);
+
+/* Unwrap old authobj, replace the payload, construct new one with newnonce */
+struct _auth_obj reload_authobj(const char *userid, const char *password,
+				const char *oldnonce, const char *newnonce,
+			const unsigned char *authobj, const int authsize,
+			const unsigned char *payload, const int paysize);
 
 #endif