Use params->version == 0 for implicit specification of version 1.0

Signed-off-by: Mattias Andrée <maandree@kth.se>

7 files changed, 84 insertions, 11 deletions

diff --git a/libar2.h b/libar2.h
index 144b430..8915a1a 100644
--- a/libar2.h
+++ b/libar2.h
@@ -55,7 +55,7 @@
 #define LIBAR2_MIN_HASHLEN ((size_t)LIBAR2_UINT_LEAST32_C__(4))
 #define LIBAR2_MAX_HASHLEN ((size_t)LIBAR2_UINT_LEAST32_C__(0xFFFFffff))
 #define LIBAR2_IS_TYPE_OK(T) ((T) == LIBAR2_ARGON2D || (T) == LIBAR2_ARGON2I || (T) == LIBAR2_ARGON2ID || (T) == LIBAR2_ARGON2DS)
-#define LIBAR2_IS_VERSION_OK(V) ((V) == LIBAR2_ARGON2_VERSION_10 || (V) == LIBAR2_ARGON2_VERSION_13)
+#define LIBAR2_IS_VERSION_OK(V) (!(V) || (V) == LIBAR2_ARGON2_VERSION_10 || (V) == LIBAR2_ARGON2_VERSION_13)
 
 /* } */
 
@@ -180,7 +180,8 @@ struct libar2_argon2_parameters {
 	enum libar2_argon2_type type;
 
 	/**
-	 * Version number
+	 * Version number; or 0 if not specified
+	 * (which is equivalent to `LIBAR2_ARGON2_VERSION_10`)
 	 * 
 	 * `libar2_latest_argon2_version` is recommended
 	 */
diff --git a/libar2_decode_params.c b/libar2_decode_params.c
index cc90c24..fa59ab2 100644
--- a/libar2_decode_params.c
+++ b/libar2_decode_params.c
@@ -65,7 +65,7 @@ libar2_decode_params(const char *str, struct libar2_argon2_parameters *params, c
 		if (*str++ != '$')
 			goto einval;
 	} else {
-		params->version = LIBAR2_ARGON2_VERSION_10;
+		params->version = 0; /* implicit LIBAR2_ARGON2_VERSION_10 */
 	}
 
 	while (*str && *str != '$') {
diff --git a/libar2_encode_params.3 b/libar2_encode_params.3
index 9f654a4..ad86115 100644
--- a/libar2_encode_params.3
+++ b/libar2_encode_params.3
@@ -72,7 +72,7 @@ with an allocation size of at least the number
 of bytes that was returned by the function in
 the previous call to it.
 .PP
-The created string will have the following format:
+The created string will have the following format
 
 .RS
 .B \(dq$%s$v=%i$m=%lu,t=%lu,p=%lu$%s$\(dq,
@@ -84,6 +84,17 @@ The created string will have the following format:
 .RI < "base64 encoded salt" >
 .RE
 
+if the version is explicitly specified, and otherwise
+
+.RS
+.B \(dq$%s$m=%lu,t=%lu,p=%lu$%s$\(dq,
+.RI < type >\fB,\fP
+.RI < "memory cost" >\fB,\fP
+.RI < "time cost" >\fB,\fP
+.RI < "parallelism" >\fB,\fP
+.RI < "base64 encoded salt" >
+.RE
+
 The string does not encode the \(dqsecret\(dq
 (pepper), \(dqassociated data\(dq, or the
 \(dqtag\(dq (message hash) length. This string
diff --git a/libar2_encode_params.c b/libar2_encode_params.c
index 498de9c..bcc46b8 100644
--- a/libar2_encode_params.c
+++ b/libar2_encode_params.c
@@ -7,22 +7,34 @@ libar2_encode_params(char *buf, const struct libar2_argon2_parameters *params)
 {
 	size_t off;
 
-#define FMT_AND_ARGS\
-	"$%s$v=%i$m=%lu,t=%lu,p=%lu$",\
-	libar2_type_to_string(params->type, LIBAR2_LOWER_CASE),\
-	(int)params->version,\
+#define FMT_AND_ARGS_HEAD\
+	"$%s$",\
+	libar2_type_to_string(params->type, LIBAR2_LOWER_CASE)
+
+#define FMT_AND_ARGS_VERSION\
+	"v=%i$",\
+	(int)params->version
+
+#define FMT_AND_ARGS_TAIL\
+	"m=%lu,t=%lu,p=%lu$",\
 	(unsigned long int)params->m_cost,\
 	(unsigned long int)params->t_cost,\
 	(unsigned long int)params->lanes
 
 	if (buf) {
-		off = (size_t)sprintf(buf, FMT_AND_ARGS);
+		off = (size_t)sprintf(buf, FMT_AND_ARGS_HEAD);
+		if (params->version)
+			off += (size_t)sprintf(&buf[off], FMT_AND_ARGS_VERSION);
+		off += (size_t)sprintf(&buf[off], FMT_AND_ARGS_TAIL);
 		off += libar2_encode_base64(&buf[off], params->salt, params->saltlen) - 1;
 		buf[off++] = '$';
 		buf[off++] = '\0';
 
 	} else {
-		off = (size_t)snprintf(NULL, 0, FMT_AND_ARGS);
+		off = (size_t)snprintf(NULL, 0, FMT_AND_ARGS_HEAD);
+		if (params->version)
+			off += (size_t)snprintf(NULL, 0, FMT_AND_ARGS_VERSION);
+		off += (size_t)snprintf(NULL, 0, FMT_AND_ARGS_TAIL);
 		off += libar2_encode_base64(NULL, params->salt, params->saltlen) - 1;
 		off += 2;
 	}
diff --git a/libar2_hash.3 b/libar2_hash.3
index da5af43..3240508 100644
--- a/libar2_hash.3
+++ b/libar2_hash.3
@@ -127,6 +127,7 @@ submission to the Password Hashing Competition).
 .B params->version
 Argon2 version number.
 .I LIBAR2_ARGON2_VERSION_10
+or 0 (implicit specification)
 for verison 1.0 and
 .I LIBAR2_ARGON2_VERSION_13
 for version 1.3.
diff --git a/libar2_hash.c b/libar2_hash.c
index 0eb9211..7f3cf3b 100644
--- a/libar2_hash.c
+++ b/libar2_hash.c
@@ -339,7 +339,7 @@ initial_hash(unsigned char hash[static 64], void *msg, size_t msglen,
 	n += store32(&block[n], (uint_least32_t)params->hashlen);
 	n += store32(&block[n], params->m_cost);
 	n += store32(&block[n], params->t_cost);
-	n += store32(&block[n], (uint_least32_t)params->version);
+	n += store32(&block[n], (uint_least32_t)(params->version ? params->version : LIBAR2_ARGON2_VERSION_10));
 	n += store32(&block[n], (uint_least32_t)params->type);
 	n += store32(&block[n], (uint_least32_t)msglen);
 	if (msglen) {
diff --git a/test.c b/test.c
index 8172e16..a799b2e 100644
--- a/test.c
+++ b/test.c
@@ -526,6 +526,54 @@ check_libar2_encode_params_libar2_decode_params(void)
 	sbuf = NULL;
 #undef PARAMSTR
 
+#define PARAMSTR "$argon2i$v=16$m=4096,t=3,p=1$fn5/f35+f38$"
+	memset(&params, 0xFF, sizeof(params));
+	assert_zueq(DECODE(PARAMSTR, "1234"), sizeof(PARAMSTR) - 1);
+	assert(params.type == LIBAR2_ARGON2I);
+	assert(params.version == LIBAR2_ARGON2_VERSION_10);
+	assert(params.t_cost == 3);
+	assert(params.m_cost == 4096);
+	assert(params.lanes == 1);
+	assert(params.salt != NULL);
+	assert(params.saltlen == 8);
+	assert(!memcmp(params.salt, "~~\x7f\x7f~~\x7f\x7f", params.saltlen));
+	assert(!params.key);
+	assert(!params.keylen);
+	assert(!params.ad);
+	assert(!params.adlen);
+	assert(params.hashlen == 3);
+	assert_zueq(libar2_encode_params(NULL, &params), sizeof(PARAMSTR));
+	assert_zueq(libar2_encode_params(pbuf, &params), sizeof(PARAMSTR));
+	assert_streq(pbuf, PARAMSTR);
+	assert(sbuf != NULL);
+	ctx_st.deallocate(sbuf, &ctx_st);
+	sbuf = NULL;
+#undef PARAMSTR
+
+#define PARAMSTR "$argon2i$m=4096,t=3,p=1$fn5/f35+f38$"
+	memset(&params, 0xFF, sizeof(params));
+	assert_zueq(DECODE(PARAMSTR, "1234"), sizeof(PARAMSTR) - 1);
+	assert(params.type == LIBAR2_ARGON2I);
+	assert(params.version == 0);
+	assert(params.t_cost == 3);
+	assert(params.m_cost == 4096);
+	assert(params.lanes == 1);
+	assert(params.salt != NULL);
+	assert(params.saltlen == 8);
+	assert(!memcmp(params.salt, "~~\x7f\x7f~~\x7f\x7f", params.saltlen));
+	assert(!params.key);
+	assert(!params.keylen);
+	assert(!params.ad);
+	assert(!params.adlen);
+	assert(params.hashlen == 3);
+	assert_zueq(libar2_encode_params(NULL, &params), sizeof(PARAMSTR));
+	assert_zueq(libar2_encode_params(pbuf, &params), sizeof(PARAMSTR));
+	assert_streq(pbuf, PARAMSTR);
+	assert(sbuf != NULL);
+	ctx_st.deallocate(sbuf, &ctx_st);
+	sbuf = NULL;
+#undef PARAMSTR
+
 #undef DECODE
 }