Merge pull request #13 from gazoo74/fix-warnings

Fix warnings

11 files changed, 51 insertions, 28 deletions

diff --git a/cli-runopts.c b/cli-runopts.c
index 467776b..5bd4c55 100644
--- a/cli-runopts.c
+++ b/cli-runopts.c
@@ -447,7 +447,7 @@ void cli_getopts(int argc, char ** argv) {
 	}
 #endif
 
-#ifdef DROPBEAR_DEFAULT_CLI_AUTHKEY
+#if defined(DROPBEAR_DEFAULT_CLI_AUTHKEY) && defined(ENABLE_CLI_PUBKEY_AUTH)
 	{
 		char *expand_path = expand_tilde(DROPBEAR_DEFAULT_CLI_AUTHKEY);
 		loadidentityfile(expand_path, 0);
@@ -498,11 +498,14 @@ multihop_passthrough_args() {
 	m_list_elem *iter;
 	/* Fill out -i, -y, -W options that make sense for all
 	 * the intermediate processes */
+#ifdef ENABLE_CLI_PUBKEY_AUTH
 	for (iter = cli_opts.privkeys->first; iter; iter = iter->next)
 	{
 		sign_key * key = (sign_key*)iter->item;
 		len += 3 + strlen(key->filename);
 	}
+#endif /* ENABLE_CLI_PUBKEY_AUTH */
+
 	len += 30; /* space for -W <size>, terminator. */
 	ret = m_malloc(len);
 	total = 0;
@@ -524,6 +527,7 @@ multihop_passthrough_args() {
 		total += written;
 	}
 
+#ifdef ENABLE_CLI_PUBKEY_AUTH
 	for (iter = cli_opts.privkeys->first; iter; iter = iter->next)
 	{
 		sign_key * key = (sign_key*)iter->item;
@@ -532,6 +536,7 @@ multihop_passthrough_args() {
 		dropbear_assert((unsigned int)written < size);
 		total += written;
 	}
+#endif /* ENABLE_CLI_PUBKEY_AUTH */
 
 	/* if args were passed, total will be not zero, and it will have a space at the end, so remove that */
 	if (total > 0) 
diff --git a/cli-session.c b/cli-session.c
index 8bf530c..843c944 100644
--- a/cli-session.c
+++ b/cli-session.c
@@ -124,6 +124,8 @@ void cli_session(int sock_in, int sock_out, struct dropbear_progress_connection
 	/* Exchange identification */
 	send_session_identification();
 
+	kexfirstinitialise(); /* initialise the kex state */
+
 	send_msg_kexinit();
 
 	session_loop(cli_sessionloop);
diff --git a/common-algo.c b/common-algo.c
index 76d3977..8970523 100644
--- a/common-algo.c
+++ b/common-algo.c
@@ -144,12 +144,15 @@ algo_type sshciphers[] = {
 #ifdef DROPBEAR_AES256
 	{"aes256-ctr", 0, &dropbear_aes256, 1, &dropbear_mode_ctr},
 #endif
+#ifdef DROPBEAR_TWOFISH_CTR
+/* twofish ctr is conditional as it hasn't been tested for interoperability, see options.h */
 #ifdef DROPBEAR_TWOFISH256
 	{"twofish256-ctr", 0, &dropbear_twofish256, 1, &dropbear_mode_ctr},
 #endif
 #ifdef DROPBEAR_TWOFISH128
 	{"twofish128-ctr", 0, &dropbear_twofish128, 1, &dropbear_mode_ctr},
 #endif
+#endif /* DROPBEAR_TWOFISH_CTR */
 #endif /* DROPBEAR_ENABLE_CTR_MODE */
 
 #ifdef DROPBEAR_ENABLE_CBC_MODE
diff --git a/common-session.c b/common-session.c
index e565570..b712f05 100644
--- a/common-session.c
+++ b/common-session.c
@@ -90,8 +90,6 @@ void common_session_init(int sock_in, int sock_out) {
 	ses.maxfd = MAX(ses.maxfd, ses.signal_pipe[0]);
 	ses.maxfd = MAX(ses.maxfd, ses.signal_pipe[1]);
 	
-	kexfirstinitialise(); /* initialise the kex state */
-
 	ses.writepayload = buf_new(TRANS_MAX_PAYLOAD_LEN);
 	ses.transseq = 0;
 
diff --git a/netio.c b/netio.c
index af34a14..74eea7b 100644
--- a/netio.c
+++ b/netio.c
@@ -70,7 +70,7 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 	struct addrinfo *r;
 	int res = 0;
 	int fastopen = 0;
-#ifdef DROPBEAR_TCP_FAST_OPEN
+#ifdef DROPBEAR_CLIENT_TCP_FAST_OPEN
 	struct msghdr message;
 #endif
 
@@ -91,14 +91,13 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 		set_piggyback_ack(c->sock);
 #endif
 
-#ifdef DROPBEAR_TCP_FAST_OPEN
+#ifdef DROPBEAR_CLIENT_TCP_FAST_OPEN
 		fastopen = (c->writequeue != NULL);
 
-		memset(&message, 0x0, sizeof(message));
-		message.msg_name = r->ai_addr;
-		message.msg_namelen = r->ai_addrlen;
-
-		if (c->writequeue) {
+		if (fastopen) {
+			memset(&message, 0x0, sizeof(message));
+			message.msg_name = r->ai_addr;
+			message.msg_namelen = r->ai_addrlen;
 			/* 6 is arbitrary, enough to hold initial packets */
 			unsigned int iovlen = 6; /* Linux msg_iovlen is a size_t */
 			struct iovec iov[6];
@@ -106,18 +105,22 @@ static void connect_try_next(struct dropbear_progress_connection *c) {
 			message.msg_iov = iov;
 			message.msg_iovlen = iovlen;
 			res = sendmsg(c->sock, &message, MSG_FASTOPEN);
-			if (res < 0 && errno != EINPROGRESS) {
-				m_free(c->errstring);
-				c->errstring = m_strdup(strerror(errno));
-				/* Not entirely sure which kind of errors are normal - 2.6.32 seems to 
-				return EPIPE for any (nonblocking?) sendmsg(). just fall back */
-				TRACE(("sendmsg tcp_fastopen failed, falling back. %s", strerror(errno)));
-				/* No kernel MSG_FASTOPEN support. Fall back below */
-				fastopen = 0;
-				/* Set to NULL to avoid trying again */
-				c->writequeue = NULL;
+			/* Returns EINPROGRESS if FASTOPEN wasn't available */
+			if (res < 0) {
+				if (errno != EINPROGRESS) {
+					m_free(c->errstring);
+					c->errstring = m_strdup(strerror(errno));
+					/* Not entirely sure which kind of errors are normal - 2.6.32 seems to 
+					return EPIPE for any (nonblocking?) sendmsg(). just fall back */
+					TRACE(("sendmsg tcp_fastopen failed, falling back. %s", strerror(errno)));
+					/* No kernel MSG_FASTOPEN support. Fall back below */
+					fastopen = 0;
+					/* Set to NULL to avoid trying again */
+					c->writequeue = NULL;
+				}
+			} else {
+				packet_queue_consume(c->writequeue, res);
 			}
-			packet_queue_consume(c->writequeue, res);
 		}
 #endif
 
@@ -310,7 +313,7 @@ void set_sock_nodelay(int sock) {
 	setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void*)&val, sizeof(val));
 }
 
-#ifdef DROPBEAR_TCP_FAST_OPEN
+#ifdef DROPBEAR_SERVER_TCP_FAST_OPEN
 void set_listen_fast_open(int sock) {
 	int qlen = MAX(MAX_UNAUTH_PER_IP, 5);
 	if (setsockopt(sock, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen)) != 0) {
diff --git a/netio.h b/netio.h
index 5d9f799..b413bdc 100644
--- a/netio.h
+++ b/netio.h
@@ -48,7 +48,7 @@ void connect_set_writequeue(struct dropbear_progress_connection *c, struct Queue
 void packet_queue_to_iovec(struct Queue *queue, struct iovec *iov, unsigned int *iov_count);
 void packet_queue_consume(struct Queue *queue, ssize_t written);
 
-#ifdef DROPBEAR_TCP_FAST_OPEN
+#ifdef DROPBEAR_SERVER_TCP_FAST_OPEN
 /* Try for any Linux builds, will fall back if the kernel doesn't support it */
 void set_listen_fast_open(int sock);
 /* Define values which may be supported by the kernel even if the libc is too old */
diff --git a/options.h b/options.h
index e2d69a9..41cc129 100644
--- a/options.h
+++ b/options.h
@@ -103,10 +103,15 @@ much traffic. */
 #define DROPBEAR_ENABLE_CBC_MODE
 
 /* Enable "Counter Mode" for ciphers. This is more secure than normal
- * CBC mode against certain attacks. This adds around 1kB to binary 
- * size and is recommended for most cases */
+ * CBC mode against certain attacks. It is recommended for security
+ * and forwards compatibility */
 #define DROPBEAR_ENABLE_CTR_MODE
 
+/* Twofish counter mode is disabled by default because it 
+has not been tested for interoperability with other SSH implementations.
+If you test it please contact the Dropbear author */
+/* #define DROPBEAR_TWOFISH_CTR */
+
 /* You can compile with no encryption if you want. In some circumstances
  * this could be safe security-wise, though make sure you know what
  * you're doing. Anyone can see everything that goes over the wire, so
diff --git a/svr-authpasswd.c b/svr-authpasswd.c
index 7a5a121..0153a53 100644
--- a/svr-authpasswd.c
+++ b/svr-authpasswd.c
@@ -33,6 +33,8 @@
 
 #ifdef ENABLE_SVR_PASSWORD_AUTH
 
+/* not constant time when strings are differing lengths. 
+ string content isn't leaked, and crypt hashes are predictable length. */
 static int constant_time_strcmp(const char* a, const char* b) {
 	size_t la = strlen(a);
 	size_t lb = strlen(b);
diff --git a/svr-main.c b/svr-main.c
index 5234086..cc59332 100644
--- a/svr-main.c
+++ b/svr-main.c
@@ -429,7 +429,7 @@ static size_t listensockets(int *socks, size_t sockcount, int *maxfd) {
 		for (n = 0; n < (unsigned int)nsock; n++) {
 			int sock = socks[sockpos + n];
 			set_sock_priority(sock, DROPBEAR_PRIO_LOWDELAY);
-#ifdef DROPBEAR_TCP_FAST_OPEN
+#ifdef DROPBEAR_SERVER_TCP_FAST_OPEN
 			set_listen_fast_open(sock);
 #endif
 		}
diff --git a/svr-session.c b/svr-session.c
index 8485905..d638d59 100644
--- a/svr-session.c
+++ b/svr-session.c
@@ -138,6 +138,8 @@ void svr_session(int sock, int childpipe) {
 
 	/* exchange identification, version etc */
 	send_session_identification();
+	
+	kexfirstinitialise(); /* initialise the kex state */
 
 	/* start off with key exchange */
 	send_msg_kexinit();
diff --git a/sysoptions.h b/sysoptions.h
index 11dc10d..185c8e6 100644
--- a/sysoptions.h
+++ b/sysoptions.h
@@ -262,9 +262,12 @@
 /* Use this string since some implementations might special-case it */
 #define DROPBEAR_KEEPALIVE_STRING "keepalive@openssh.com"
 
-/* Linux will attempt TCP fast open, falling back if not supported by the kernel */
+/* Linux will attempt TCP fast open, falling back if not supported by the kernel.
+ * Currently server is enabled but client is disabled by default until there
+ * is further compatibility testing */
 #ifdef __linux__
-#define DROPBEAR_TCP_FAST_OPEN 1
+#define DROPBEAR_SERVER_TCP_FAST_OPEN
+/* #define DROPBEAR_CLIENT_TCP_FAST_OPEN */
 #endif
 
 /* no include guard for this file */