feat: add path movement control

Author: Dawoox

include/server.h

@@ -26,6 +26,7 @@ typedef struct {
     struct sockaddr_in data_sock;
     int data_trf_fd;
     bool is_auth;
+    char home[PATH_MAX];
 } client_t;
 
 typedef struct {

src/commands/dir.c

@@ -13,6 +13,14 @@
 
 #include "server.h"
 
+static bool is_path_allowed(char const *home, char const *newpath)
+{
+    char const *real_newpath = realpath(newpath, NULL);
+    if (real_newpath == NULL)
+        return false;
+    return strncmp(home, real_newpath, strlen(home)) == 0;
+}
+
 void cmd_pwd_handler(client_t *client, __attribute__((unused)) const char *_)
 {
     char buffer[512];
@@ -37,6 +45,10 @@ static int check_for_path_errors(const char *args, const char *realpath_buff,
         write_msg_to_client(client->control_fd, "550 Error occurred.");
         return -1;
     }
+    if (!is_path_allowed(client->home, realpath_buff)) {
+        write_msg_to_client(client->control_fd, "550 Requested action not taken.");
+        return -1;
+    }
     return 0;
 }
 

src/server.c

@@ -27,6 +27,14 @@ static client_t *get_empty_client_slot(server_t *server)
     return NULL;
 }
 
+static void init_client(client_t *client, const server_t *server)
+{
+    client->data_fd = -1;
+    client->data_trf_fd = -1;
+    strcpy(client->username, "");
+    strcpy(client->home, server->anonymous_default_path);
+}
+
 static void searching_new_clients(server_t *server)
 {
     const struct sockaddr_in client_addr = {0};
@@ -41,9 +49,7 @@ static void searching_new_clients(server_t *server)
         client = get_empty_client_slot(server);
         client->control_fd = accept(server->server_fd,
             (struct sockaddr*) &client_addr, &client_len);
-        client->data_fd = -1;
-        client->data_trf_fd = -1;
-        strcpy(client->username, "");
+        init_client(client, server);
         strcpy(client->currPath, realpath(server->anonymous_default_path,
             NULL));
         printf("[INFO] New client connection\n");