packet: Fix ssh_packet_socket_callback() return value

According to the documentation the return value is the number of
processed bytes, so the returned value is never negative. We should not
use ssize_t in public headers as it isn't available on Windows! We only
have it defined in priv.h!

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

include/libssh/callbacks.h

@@ -56,7 +56,7 @@ typedef void (*ssh_callback_int) (int code, void *user);
  * @returns number of bytes processed by the callee. The remaining bytes will
  * be sent in the next callback message, when more data is available.
  */
-typedef ssize_t (*ssh_callback_data) (const void *data, size_t len, void *user);
+typedef size_t (*ssh_callback_data) (const void *data, size_t len, void *user);
 
 typedef void (*ssh_callback_int_int) (int code, int errno_code, void *user);
 

include/libssh/packet.h

@@ -67,7 +67,7 @@ int ssh_packet_send_unimplemented(ssh_session session, uint32_t seqnum);
 int ssh_packet_parse_type(ssh_session session);
 //int packet_flush(ssh_session session, int enforce_blocking);
 
-ssize_t ssh_packet_socket_callback(const void *data, size_t len, void *user);
+size_t ssh_packet_socket_callback(const void *data, size_t len, void *user);
 void ssh_packet_register_socket_callback(ssh_session session, struct ssh_socket_struct *s);
 void ssh_packet_set_callbacks(ssh_session session, ssh_packet_callbacks callbacks);
 void ssh_packet_remove_callbacks(ssh_session session, ssh_packet_callbacks callbacks);

src/client.c

@@ -94,7 +94,7 @@ static void socket_callback_connected(int code, int errno_code, void *user)
  * @param  user is a pointer to session
  * @returns Number of bytes processed, or zero if the banner is not complete.
  */
-static ssize_t callback_receive_banner(const void *data, size_t len, void *user)
+static size_t callback_receive_banner(const void *data, size_t len, void *user)
 {
     char *buffer = (char *)data;
     ssh_session session = (ssh_session) user;
@@ -107,7 +107,7 @@ static ssize_t callback_receive_banner(const void *data, size_t len, void *user)
                       "Wrong state in callback_receive_banner : %d",
                       session->session_state);
 
-        return SSH_ERROR;
+        return 0;
     }
     for (i = 0; i < len; ++i) {
 #ifdef WITH_PCAP

src/packet.c

@@ -1054,7 +1054,7 @@ static bool ssh_packet_need_rekey(ssh_session session,
  * @len length of data received. It might not be enough for a complete packet
  * @returns number of bytes read and processed.
  */
-ssize_t ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user)
+size_t ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user)
 {
     ssh_session session = (ssh_session)user;
     uint32_t blocksize = 8;
@@ -1069,7 +1069,7 @@ ssize_t ssh_packet_socket_callback(const void *data, size_t receivedlen, void *u
     size_t packet_remaining;
     uint32_t packet_len, compsize, payloadsize;
     uint8_t padding;
-    uint32_t processed = 0; /* number of bytes processed from the callback */
+    size_t processed = 0; /* number of bytes processed from the callback */
     enum ssh_packet_filter_result_e filter_result;
     struct ssh_crypto_struct *crypto = NULL;
     bool etm = false;
@@ -1382,7 +1382,7 @@ ssize_t ssh_packet_socket_callback(const void *data, size_t receivedlen, void *u
 
 error:
     session->session_state= SSH_SESSION_STATE_ERROR;
-    SSH_LOG(SSH_LOG_PACKET,"Packet: processed %u bytes", processed);
+    SSH_LOG(SSH_LOG_PACKET,"Packet: processed %zu bytes", processed);
     return processed;
 }
 

src/server.c

@@ -459,12 +459,12 @@ error:
  * @param  user is a pointer to session
  * @returns Number of bytes processed, or zero if the banner is not complete.
  */
-static ssize_t callback_receive_banner(const void *data, size_t len, void *user) {
+static size_t callback_receive_banner(const void *data, size_t len, void *user) {
     char *buffer = (char *) data;
     ssh_session session = (ssh_session) user;
     char *str = NULL;
     size_t i;
-    ssize_t ret = 0;
+    size_t processed = 0;
 
     for (i = 0; i < len; i++) {
 #ifdef WITH_PCAP
@@ -485,13 +485,13 @@ static ssize_t callback_receive_banner(const void *data, size_t len, void *user)
 
             str = strdup(buffer);
             /* number of bytes read */
-            ret = i + 1;
+            processed = i + 1;
             session->clientbanner = str;
             session->session_state = SSH_SESSION_STATE_BANNER_RECEIVED;
             SSH_LOG(SSH_LOG_PACKET, "Received banner: %s", str);
             session->ssh_connection_callback(session);
 
-            return ret;
+            return processed;
         }
 
         if(i > 127) {
@@ -503,7 +503,7 @@ static ssize_t callback_receive_banner(const void *data, size_t len, void *user)
         }
     }
 
-    return ret;
+    return processed;
 }
 
 /* returns 0 until the key exchange is not finished */