Add support for PBKDF2-SHA512 password hashing.

ChangeLog.txt

@@ -46,6 +46,7 @@ Broker:
 - Add `mosquitto_kick_client_by_clientid()` and `mosquitto_kick_client_by_username()`
   functions, which can be used by plugins to disconnect clients.
 - Add support for handling $CONTROL/ topics in plugins.
+- Add support for PBKDF2-SHA512 password hashing.
 
 Client library:
 - Client no longer generates random client ids for v3.1.1 clients, these are

man/mosquitto_passwd.1.xml

@@ -17,6 +17,9 @@
 	<refsynopsisdiv>
 		<cmdsynopsis>
 			<command>mosquitto_passwd</command>
+			<group>
+				<arg choice='plain'><option>-H</option> <replaceable>hash</replaceable></arg>
+			</group>
 			<group>
 				<arg choice='plain'><option>-c</option></arg>
 				<arg choice='plain'><option>-D</option></arg>
@@ -26,6 +29,9 @@
 		</cmdsynopsis>
 		<cmdsynopsis>
 			<command>mosquitto_passwd</command>
+			<group>
+				<arg choice='plain'><option>-H</option> <replaceable>hash</replaceable></arg>
+			</group>
 			<arg choice='plain'><option>-b</option></arg>
 			<arg choice='plain'><replaceable>passwordfile</replaceable></arg>
 			<arg choice='plain'><replaceable>username</replaceable></arg>
@@ -74,6 +80,18 @@
 						file.</para>
 				</listitem>
 			</varlistentry>
+			<varlistentry>
+				<term><option>-H</option></term>
+				<listitem>
+					<para>Choose the hash to use. Can be one of
+						<replaceable>sha512-pbkdf2</replaceable> or
+						<replaceable>sha512</replaceable>. Defaults to
+						<replaceable>sha512-pbkdf2</replaceable>. The
+						<replaceable>sha512</replaceable> option is provided for
+						creating password files for use with Mosquitto 1.6
+						and earlier.</para>
+				</listitem>
+			</varlistentry>
 			<varlistentry>
 				<term><option>-U</option></term>
 				<listitem>

src/mosquitto_broker_internal.h

@@ -174,6 +174,11 @@ enum mosquitto_msg_origin{
 	mosq_mo_broker = 1
 };
 
+enum mosquitto_pwhash_type{
+	pw_sha512 = 6,
+	pw_sha512_pbkdf2 = 7
+};
+
 struct mosquitto__auth_plugin{
 	void *lib;
 	void *user_data;
@@ -449,14 +454,15 @@ struct mosquitto_client_msg{
 };
 
 struct mosquitto__unpwd{
+	UT_hash_handle hh;
 	char *username;
 	char *password;
 #ifdef WITH_TLS
+	unsigned char *salt;
 	unsigned int password_len;
 	unsigned int salt_len;
-	unsigned char *salt;
 #endif
-	UT_hash_handle hh;
+	enum mosquitto_pwhash_type hashtype;
 };
 
 struct mosquitto__acl{

src/mosquitto_passwd.c

@@ -54,6 +54,11 @@ Contributors:
 
 #include "misc_mosq.h"
 
+enum pwhash{
+	pw_sha512 = 6,
+	pw_sha512_pbkdf2 = 7,
+};
+
 struct cb_helper {
 	const char *line;
 	const char *username;
@@ -69,6 +74,7 @@ static FILE *mpw_tmpfile(void)
 #else
 
 static char alphanum[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+static enum pwhash hashtype = pw_sha512_pbkdf2;
 
 static unsigned char tmpfile_path[36];
 static FILE *mpw_tmpfile(void)
@@ -132,12 +138,14 @@ int base64_encode(unsigned char *in, unsigned int in_len, char **encoded)
 void print_usage(void)
 {
 	printf("mosquitto_passwd is a tool for managing password files for mosquitto.\n\n");
-	printf("Usage: mosquitto_passwd [-c | -D] passwordfile username\n");
+	printf("Usage: mosquitto_passwd [-H sha512 | -H sha512-pbkdf2] [-c | -D] passwordfile username\n");
-	printf("       mosquitto_passwd -b passwordfile username password\n");
+	printf("       mosquitto_passwd [-H sha512 | -H sha512-pbkdf2] -b passwordfile username password\n");
 	printf("       mosquitto_passwd -U passwordfile\n");
 	printf(" -b : run in batch mode to allow passing passwords on the command line.\n");
 	printf(" -c : create a new password file. This will overwrite existing files.\n");
 	printf(" -D : delete the username rather than adding/updating its password.\n");
+	printf(" -H : specify the hashing algorithm. Defaults to sha512-pbkdf2, which is recommended.\n");
+	printf("      Mosquitto 1.6 and earlier defaulted to sha512.\n");
 	printf(" -U : update a plain text password file to use hashed passwords.\n");
 	printf("\nSee https://mosquitto.org/ for more information.\n\n");
 }
@@ -177,6 +185,7 @@ int output_new_password(FILE *fptr, const char *username, const char *password)
 		return 1;
 	}
 
+	if(hashtype == pw_sha512){
 #if OPENSSL_VERSION_NUMBER < 0x10100000L
 		EVP_MD_CTX_init(&context);
 		EVP_DigestInit_ex(&context, digest, NULL);
@@ -192,6 +201,12 @@ int output_new_password(FILE *fptr, const char *username, const char *password)
 		EVP_DigestFinal_ex(context, hash, &hash_len);
 		EVP_MD_CTX_free(context);
 #endif
+	}else{
+		hash_len = sizeof(hash);
+		PKCS5_PBKDF2_HMAC(password, strlen(password),
+			salt, SALT_LEN, 20000,
+			digest, hash_len, hash);
+	}
 
 	rc = base64_encode(hash, hash_len, &hash64);
 	if(rc){
@@ -201,7 +216,7 @@ int output_new_password(FILE *fptr, const char *username, const char *password)
 		return 1;
 	}
 
-	fprintf(fptr, "%s:$6$%s$%s\n", username, salt64, hash64);
+	fprintf(fptr, "%s:$%d$%s$%s\n", username, hashtype, salt64, hash64);
 	free(salt64);
 	free(hash64);
 
@@ -331,10 +346,8 @@ static int update_pwuser_cb(FILE *fptr, FILE *ftmp, const char *username, const
 {
 	int rc = 0;
 
-	printf("%s\n", username);
 	if(strcmp(username, helper->username)){
 		/* If this isn't the matching user, then writing out the exiting line */
-		printf("%s\n", line);
 		fprintf(ftmp, "%s", line);
 	}else{
 		/* Write out a new line for our matching username */
@@ -520,6 +533,7 @@ int main(int argc, char *argv[])
 	int rc;
 	bool do_update_file = false;
 	char *backup_file;
+	int idx;
 
 	signal(SIGINT, handle_sigint);
 	signal(SIGTERM, handle_sigint);
@@ -537,45 +551,63 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
-	if(!strcmp(argv[1], "-c")){
+	idx = 1;
+	if(!strcmp(argv[1], "-H")){
+		if(argc < 5){
+			fprintf(stderr, "Error: -H argument given but not enough other arguments.\n");
+			return 1;
+		}
+		if(!strcmp(argv[2], "sha512")){
+			hashtype = pw_sha512;
+		}else if(!strcmp(argv[2], "sha512-pbkdf2")){
+			hashtype = pw_sha512_pbkdf2;
+		}else{
+			fprintf(stderr, "Error: Unknown hash type '%s'\n", argv[2]);
+			return 1;
+		}
+		idx += 2;
+		argc -= 2;
+	}
+
+	if(!strcmp(argv[idx], "-c")){
 		create_new = true;
 		if(argc != 4){
 			fprintf(stderr, "Error: -c argument given but password file or username missing.\n");
 			return 1;
 		}else{
-			password_file_tmp = argv[2];
+			password_file_tmp = argv[idx+1];
-			username = argv[3];
+			username = argv[idx+2];
 		}
-	}else if(!strcmp(argv[1], "-D")){
+	}else if(!strcmp(argv[idx], "-D")){
 		delete_user = true;
 		if(argc != 4){
 			fprintf(stderr, "Error: -D argument given but password file or username missing.\n");
 			return 1;
 		}else{
-			password_file_tmp = argv[2];
+			password_file_tmp = argv[idx+1];
-			username = argv[3];
+			username = argv[idx+2];
 		}
-	}else if(!strcmp(argv[1], "-b")){
+	}else if(!strcmp(argv[idx], "-b")){
 		batch_mode = true;
 		if(argc != 5){
 			fprintf(stderr, "Error: -b argument given but password file, username or password missing.\n");
 			return 1;
 		}else{
-			password_file_tmp = argv[2];
+			password_file_tmp = argv[idx+1];
-			username = argv[3];
+			username = argv[idx+2];
-			password_cmd = argv[4];
+			password_cmd = argv[idx+3];
 		}
-	}else if(!strcmp(argv[1], "-U")){
+	}else if(!strcmp(argv[idx], "-U")){
 		if(argc != 3){
 			fprintf(stderr, "Error: -U argument given but password file missing.\n");
 			return 1;
 		}else{
 			do_update_file = true;
-			password_file_tmp = argv[2];
+			password_file_tmp = argv[idx+1];
 		}
 	}else if(argc == 3){
-		password_file_tmp = argv[1];
+		password_file_tmp = argv[idx];
-		username = argv[2];
+		username = argv[idx+1];
 	}else{
 		print_usage();
 		return 1;

src/security_default.c

@@ -33,7 +33,7 @@ static int acl__cleanup(struct mosquitto_db *db, bool reload);
 static int unpwd__cleanup(struct mosquitto__unpwd **unpwd, bool reload);
 static int psk__file_parse(struct mosquitto_db *db, struct mosquitto__unpwd **psk_id, const char *psk_file);
 #ifdef WITH_TLS
-static int pw__digest(const char *password, const unsigned char *salt, unsigned int salt_len, unsigned char *hash, unsigned int *hash_len);
+static int pw__digest(const char *password, const unsigned char *salt, unsigned int salt_len, unsigned char *hash, unsigned int *hash_len, enum mosquitto_pwhash_type hashtype);
 static int base64__decode(char *in, unsigned char **decoded, unsigned int *decoded_len);
 static int mosquitto__memcmp_const(const void *ptr1, const void *b, size_t len);
 #endif
@@ -773,12 +773,22 @@ static int unpwd__decode_passwords(struct mosquitto__unpwd **unpwd)
 	unsigned char *password;
 	unsigned int password_len;
 	int rc;
+	int hashtype;
 
 	HASH_ITER(hh, *unpwd, u, tmp){
 		/* Need to decode password into hashed data + salt. */
 		if(u->password){
 			token = strtok(u->password, "$");
-			if(token && !strcmp(token, "6")){
+			if(token){
+				if(!strcmp(token, "6")){
+					hashtype = pw_sha512;
+				}else if(!strcmp(token, "7")){
+					hashtype = pw_sha512_pbkdf2;
+				}else{
+					log__printf(NULL, MOSQ_LOG_ERR, "Error: Invalid password hash type for user %s, removing entry.", u->username);
+					unpwd__free_item(unpwd, u);
+					continue;
+				}
 				token = strtok(NULL, "$");
 				if(token){
 					rc = base64__decode(token, &salt, &salt_len);
@@ -792,6 +802,7 @@ static int unpwd__decode_passwords(struct mosquitto__unpwd **unpwd)
 								mosquitto__free(u->password);
 								u->password = (char *)password;
 								u->password_len = password_len;
+								u->hashtype = hashtype;
 							}else{
 								log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to decode password for user %s, removing entry.", u->username);
 								unpwd__free_item(unpwd, u);
@@ -953,7 +964,7 @@ int mosquitto_unpwd_check_default(struct mosquitto_db *db, struct mosquitto *con
 		if(u->password){
 			if(context->password){
 #ifdef WITH_TLS
-				rc = pw__digest(context->password, u->salt, u->salt_len, hash, &hash_len);
+				rc = pw__digest(context->password, u->salt, u->salt_len, hash, &hash_len, u->hashtype);
 				if(rc == MOSQ_ERR_SUCCESS){
 					if(hash_len == u->password_len && !mosquitto__memcmp_const(u->password, hash, hash_len)){
 						return MOSQ_ERR_SUCCESS;
@@ -1250,11 +1261,14 @@ int mosquitto_psk_key_get_default(struct mosquitto_db *db, struct mosquitto *con
 }
 
 #ifdef WITH_TLS
-int pw__digest(const char *password, const unsigned char *salt, unsigned int salt_len, unsigned char *hash, unsigned int *hash_len)
+int pw__digest(const char *password, const unsigned char *salt, unsigned int salt_len, unsigned char *hash, unsigned int *hash_len, enum mosquitto_pwhash_type hashtype)
 {
 	const EVP_MD *digest;
 #if OPENSSL_VERSION_NUMBER < 0x10100000L
 	EVP_MD_CTX context;
+#else
+	EVP_MD_CTX *context;
+#endif
 
 	digest = EVP_get_digestbyname("sha512");
 	if(!digest){
@@ -1262,6 +1276,8 @@ int pw__digest(const char *password, const unsigned char *salt, unsigned int sal
 		return 1;
 	}
 
+	if(hashtype == pw_sha512){
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
 		EVP_MD_CTX_init(&context);
 		EVP_DigestInit_ex(&context, digest, NULL);
 		EVP_DigestUpdate(&context, password, strlen(password));
@@ -1270,14 +1286,6 @@ int pw__digest(const char *password, const unsigned char *salt, unsigned int sal
 		EVP_DigestFinal_ex(&context, hash, hash_len);
 		EVP_MD_CTX_cleanup(&context);
 #else
-	EVP_MD_CTX *context;
-
-	digest = EVP_get_digestbyname("sha512");
-	if(!digest){
-		// FIXME fprintf(stderr, "Error: Unable to create openssl digest.\n");
-		return 1;
-	}
-
 		context = EVP_MD_CTX_new();
 		EVP_DigestInit_ex(context, digest, NULL);
 		EVP_DigestUpdate(context, password, strlen(password));
@@ -1286,6 +1294,12 @@ int pw__digest(const char *password, const unsigned char *salt, unsigned int sal
 		EVP_DigestFinal_ex(context, hash, hash_len);
 		EVP_MD_CTX_free(context);
 #endif
+	}else{
+		*hash_len = EVP_MAX_MD_SIZE;
+		PKCS5_PBKDF2_HMAC(password, strlen(password),
+			salt, salt_len, 20000,
+			digest, *hash_len, hash);
+	}
 
 	return MOSQ_ERR_SUCCESS;
 }