Make implementations used for AES128-CTR and GHASH configurable.

src/config.c

@@ -37,6 +37,7 @@
 #include <dirent.h>
 #include <libgen.h>
 #include <stdarg.h>
+#include <strings.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -85,6 +86,8 @@ static void default_config(fastd_config *conf) {
 	conf->secret = NULL;
 	conf->key_valid = 3600;		/* 60 minutes */
 	conf->key_refresh = 3300;	/* 55 minutes */
+	conf->alg_impl_aes128ctr = ALG_IMPL_DEFAULT;
+	conf->alg_impl_ghash = ALG_IMPL_DEFAULT;
 
 	conf->peer_dirs = NULL;
 	conf->peers = NULL;
@@ -174,6 +177,32 @@ bool fastd_config_method(fastd_context *ctx, fastd_config *conf, const char *nam
 	exit_bug(ctx, "MAX_METHODS too low");
 }
 
+bool fastd_config_algorithm(fastd_context *ctx, fastd_config *conf, const char *alg, const char *impl) {
+	if (!strcasecmp(alg, "aes128-ctr") || !strcasecmp(alg, "aes128") || !strcasecmp(alg, "aes-ctr") || !strcasecmp(alg, "aes")) {
+		if (!strcasecmp(impl, "default"))
+			conf->alg_impl_aes128ctr = ALG_IMPL_DEFAULT;
+		else if (!strcasecmp(impl, "algif"))
+			conf->alg_impl_aes128ctr = ALG_IMPL_ALGIF;
+		else
+			return false;
+
+		return true;
+	}
+	else if (!strcasecmp(alg, "ghash")) {
+		if (!strcasecmp(impl, "default"))
+			conf->alg_impl_ghash = ALG_IMPL_DEFAULT;
+		else if (!strcasecmp(impl, "algif"))
+			conf->alg_impl_ghash = ALG_IMPL_ALGIF;
+		else
+			return false;
+
+		return true;
+	}
+	else {
+		return false;
+	}
+}
+
 bool fastd_config_add_log_file(fastd_context *ctx, fastd_config *conf, const char *name, int level) {
 	char *name2 = strdup(name);
 	char *name3 = strdup(name);

src/config.l

@@ -97,6 +97,8 @@ yes		{ TOKEN(TOK_YES); }
 no		{ TOKEN(TOK_NO); }
 port		{ TOKEN(TOK_PORT); }
 float		{ TOKEN(TOK_FLOAT); }
+algorithm	{ TOKEN(TOK_ALGORITHM); }
+use		{ TOKEN(TOK_USE); }
 
 [0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3} {
 			UPDATE_LOCATION;

src/config.y

@@ -95,6 +95,8 @@
 %token TOK_NO
 %token TOK_PORT
 %token TOK_FLOAT
+%token TOK_ALGORITHM
+%token TOK_USE
 
 %token <addr> TOK_ADDR
 %token <addr6> TOK_ADDR6
@@ -136,6 +138,7 @@ statement:	TOK_LOG log ';'
 	|	TOK_MODE mode ';'
 	|	TOK_PROTOCOL protocol ';'
 	|	TOK_METHOD method ';'
+	|	TOK_ALGORITHM algorithm ';'
 	|	TOK_SECRET secret ';'
 	|	TOK_ON TOK_UP on_up ';'
 	|	TOK_ON TOK_DOWN on_down ';'
@@ -226,6 +229,14 @@ method:		TOK_STRING {
 		}
 	;
 
+algorithm:	TOK_STRING TOK_USE TOK_STRING {
+			if (!fastd_config_algorithm(ctx, conf, $1->str, $3->str)) {
+				fastd_config_error(&@$, ctx, conf, filename, depth, "invalid algorithm/implementation");
+				YYERROR;
+			}
+		}
+	;
+
 secret:		TOK_STRING	{ free(conf->secret); conf->secret = strdup($1->str); }
 	;
 

src/fastd.h

@@ -163,6 +163,8 @@ struct _fastd_config {
 	char *secret;
 	unsigned key_valid;
 	unsigned key_refresh;
+	fastd_alg_impl alg_impl_aes128ctr;
+	fastd_alg_impl alg_impl_ghash;
 
 	fastd_string_stack *peer_dirs;
 	fastd_peer_config *peers;
@@ -247,6 +249,7 @@ bool fastd_read_config(fastd_context *ctx, fastd_config *conf, const char *filen
 
 bool fastd_config_protocol(fastd_context *ctx, fastd_config *conf, const char *name);
 bool fastd_config_method(fastd_context *ctx, fastd_config *conf, const char *name);
+bool fastd_config_algorithm(fastd_context *ctx, fastd_config *conf, const char *alg, const char *impl);
 bool fastd_config_add_log_file(fastd_context *ctx, fastd_config *conf, const char *name, int level);
 void fastd_configure(fastd_context *ctx, fastd_config *conf, int argc, char *const argv[]);
 void fastd_reconfigure(fastd_context *ctx, fastd_config *conf);

src/linux_alg.c

@@ -36,38 +36,60 @@
 #endif
 
 
-void fastd_linux_alg_init(fastd_context *ctx) {
+static int init_aesctr(fastd_context *ctx) {
-	ctx->algfd_ghash = socket(AF_ALG, SOCK_SEQPACKET, 0);
+	int fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
-	if (ctx->algfd_ghash < 0)
+	if (fd < 0)
-		goto ghash_done;
+		goto error;
+
+	struct sockaddr_alg sa = {};
+	sa.salg_family = AF_ALG;
+	strcpy((char*)sa.salg_type, "skcipher");
+	strcpy((char*)sa.salg_name, "ctr(aes)");
+	if (bind(fd, (struct sockaddr*)&sa, sizeof(sa)) < 0)
+		goto error;
+
+	return fd;
+
+ error:
+	if (fd >= 0)
+		close(fd);
+
+	pr_info(ctx, "no kernel support for AES-CTR was found, falling back to userspace implementation");
+	return -1;
+}
+
+static int init_ghash(fastd_context *ctx) {
+	int fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
+	if (fd < 0)
+		goto error;
 
 	struct sockaddr_alg sa = {};
 	sa.salg_family = AF_ALG;
 	strcpy((char*)sa.salg_type, "hash");
 	strcpy((char*)sa.salg_name, "ghash");
-	if (bind(ctx->algfd_ghash, (struct sockaddr*)&sa, sizeof(sa)) < 0) {
+	if (bind(fd, (struct sockaddr*)&sa, sizeof(sa)) < 0)
-		close(ctx->algfd_ghash);
+		goto error;
-		ctx->algfd_ghash = -1;
+
-	}
+	return fd;
+
+ error:
+	if (fd >= 0)
+		close(fd);
 
- ghash_done:
-	if (ctx->algfd_ghash < 0)
 	pr_info(ctx, "no kernel support for GHASH was found, falling back to userspace implementation");
+	return -1;
+}
 
-	ctx->algfd_aesctr = socket(AF_ALG, SOCK_SEQPACKET, 0);
+void fastd_linux_alg_init(fastd_context *ctx) {
-	if (ctx->algfd_aesctr < 0)
+	if (ctx->conf->alg_impl_aes128ctr == ALG_IMPL_ALGIF)
-		goto aesctr_done;
+		ctx->algfd_aesctr = init_aesctr(ctx);
-
+	else
-	strcpy((char*)sa.salg_type, "skcipher");
-	strcpy((char*)sa.salg_name, "ctr(aes)");
-	if (bind(ctx->algfd_aesctr, (struct sockaddr*)&sa, sizeof(sa)) < 0) {
-		close(ctx->algfd_aesctr);
 		ctx->algfd_aesctr = -1;
-	}
 
- aesctr_done:
+	if (ctx->conf->alg_impl_ghash == ALG_IMPL_ALGIF)
-	if (ctx->algfd_aesctr < 0)
+		ctx->algfd_ghash = init_ghash(ctx);
-		pr_info(ctx, "no kernel support for AES-CTR was found, falling back to userspace implementation");
+	else
+		ctx->algfd_ghash = -1;
 }
 
 void fastd_linux_alg_close(fastd_context *ctx) {
@@ -78,43 +100,6 @@ void fastd_linux_alg_close(fastd_context *ctx) {
 		close(ctx->algfd_aesctr);
 }
 
-
-int fastd_linux_alg_ghash_init(fastd_context *ctx, uint8_t key[16]) {
-	if (ctx->algfd_ghash < 0)
-		return -1;
-
-	if (setsockopt(ctx->algfd_ghash, SOL_ALG, ALG_SET_KEY, key, 16) < 0) {
-		pr_error_errno(ctx, "fastd_linux_alg_ghash_init: setsockopt");
-		return -1;
-	}
-
-	int ret = accept(ctx->algfd_ghash, NULL, NULL);
-
-	if (ret < 0) {
-		pr_error_errno(ctx, "fastd_linux_alg_ghash_init: accept");
-		return -1;
-	}
-
-	return ret;
-}
-
-bool fastd_linux_alg_ghash(fastd_context *ctx, int fd, uint8_t out[16], const void *data, size_t len) {
-	if (!len)
-		return false;
-
-	if (write(fd, data, len) < 0) {
-		pr_error_errno(ctx, "fastd_linux_alg_ghash: write");
-		return false;
-	}
-
-	if (read(fd, out, 16) < 16) {
-		pr_error_errno(ctx, "fastd_linux_alg_ghash: read");
-		return false;
-	}
-
-	return true;
-}
-
 int fastd_linux_alg_aesctr_init(fastd_context *ctx, uint8_t *key, size_t keylen) {
 	if (ctx->algfd_aesctr < 0)
 		return -1;
@@ -173,3 +158,39 @@ bool fastd_linux_alg_aesctr(fastd_context *ctx, int fd, void *out, const void *i
 
 	return true;
 }
+
+int fastd_linux_alg_ghash_init(fastd_context *ctx, uint8_t key[16]) {
+	if (ctx->algfd_ghash < 0)
+		return -1;
+
+	if (setsockopt(ctx->algfd_ghash, SOL_ALG, ALG_SET_KEY, key, 16) < 0) {
+		pr_error_errno(ctx, "fastd_linux_alg_ghash_init: setsockopt");
+		return -1;
+	}
+
+	int ret = accept(ctx->algfd_ghash, NULL, NULL);
+
+	if (ret < 0) {
+		pr_error_errno(ctx, "fastd_linux_alg_ghash_init: accept");
+		return -1;
+	}
+
+	return ret;
+}
+
+bool fastd_linux_alg_ghash(fastd_context *ctx, int fd, uint8_t out[16], const void *data, size_t len) {
+	if (!len)
+		return false;
+
+	if (write(fd, data, len) < 0) {
+		pr_error_errno(ctx, "fastd_linux_alg_ghash: write");
+		return false;
+	}
+
+	if (read(fd, out, 16) < 16) {
+		pr_error_errno(ctx, "fastd_linux_alg_ghash: read");
+		return false;
+	}
+
+	return true;
+}

src/types.h

@@ -38,6 +38,10 @@ typedef enum _fastd_mode {
 	MODE_TUN,
 } fastd_mode;
 
+typedef enum _fastd_alg_impl {
+	ALG_IMPL_DEFAULT,
+	ALG_IMPL_ALGIF,
+} fastd_alg_impl;
 
 typedef struct _fastd_buffer fastd_buffer;