resolve callback crash

examples/sample.c

@@ -40,6 +40,7 @@ char *user;
 int sftp;
 char *cmds[MAXCMD];
 struct termios terminal;
+
 void do_sftp(ssh_session session);
 
 static int auth_callback(const char *prompt, char *buf, size_t len,
@@ -68,6 +69,11 @@ static int auth_callback(const char *prompt, char *buf, size_t len,
   return 0;
 }
 
+struct ssh_callbacks_struct cb = {
+		.auth_function=auth_callback,
+		.userdata=NULL
+};
+
 static void add_cmd(char *cmd){
     int n;
     for(n=0;cmds[n] && (n<MAXCMD);n++);
@@ -537,17 +543,10 @@ int main(int argc, char **argv){
     char buf[10];
     unsigned char *hash = NULL;
     int hlen;
-    ssh_callbacks cb;
-
     session = ssh_new();
 
-    cb = malloc(sizeof(ssh_callbacks));
-
-    cb->auth_function = auth_callback;
-    cb->userdata = NULL;
-
-    ssh_callbacks_init(cb);
-    ssh_set_callbacks(session, cb);
+    ssh_callbacks_init(&cb);
+    ssh_set_callbacks(session,&cb);
 
     if(ssh_options_getopt(session, &argc, argv)) {
       fprintf(stderr, "error parsing command line :%s\n",

include/libssh/callbacks.h

@@ -79,7 +79,7 @@ typedef struct ssh_callbacks_struct * ssh_callbacks;
  * evolves with time.
  */
 #define ssh_callbacks_init(p) do {\
-	p->size=sizeof(*p); \
+	(p)->size=sizeof(*(p)); \
 } while(0);
 
 LIBSSH_API int ssh_set_callbacks(ssh_session session, ssh_callbacks cb);