Fix: relayd: hostname check is too restrictive

[lttng-tools.git] / src / bin / lttng-relayd / session.c

diff --git a/src/bin/lttng-relayd/session.c b/src/bin/lttng-relayd/session.c
index 8f61e715fe5af8490f2cc8c5e7822a75e3d3bbde..00dfbd7d2e6e5c873b01dd66b80a7d3098198162 100644 (file)
--- a/src/bin/lttng-relayd/session.c
+++ b/src/bin/lttng-relayd/session.c
@@ -23,6 +23,7 @@
 #include <common/time.h>
 #include <common/utils.h>
 #include <common/uuid.h>
+#include <common/compat/path.h>
 #include <urcu/rculist.h>
 
 #include <sys/stat.h>
@@ -185,10 +186,10 @@ static int session_set_anonymous_chunk(struct relay_session *session)
        int ret = 0;
        struct lttng_trace_chunk *chunk = NULL;
        enum lttng_trace_chunk_status status;
-       struct lttng_directory_handle output_directory;
+       struct lttng_directory_handle *output_directory;
 
-       ret = session_init_output_directory_handle(session, &output_directory);
-       if (ret) {
+       output_directory = session_create_output_directory_handle(session);
+       if (!output_directory) {
                goto end;
        }
 
@@ -203,19 +204,51 @@ static int session_set_anonymous_chunk(struct relay_session *session)
                goto end;
        }
 
-       status = lttng_trace_chunk_set_as_owner(chunk, &output_directory);
+       status = lttng_trace_chunk_set_as_owner(chunk, output_directory);
        if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                ret = -1;
                goto end;
        }
+       output_directory = NULL;
        session->current_trace_chunk = chunk;
        chunk = NULL;
 end:
        lttng_trace_chunk_put(chunk);
-       lttng_directory_handle_fini(&output_directory);
+       lttng_directory_handle_put(output_directory);
        return ret;
 }
 
+/*
+ * Check if a name is safe to use in a path.
+ *
+ * A name that is deemed "path-safe":
+ *   - Does not contains a path separator (/ or \, platform dependant),
+ *   - Does not start with a '.' (hidden file/folder),
+ *   - Is not empty.
+ */
+static bool is_name_path_safe(const char *name)
+{
+       const size_t name_len = strlen(name);
+
+       /* Not empty. */
+       if (name_len == 0) {
+               WARN("An empty name is not allowed to be used in a path");
+               return false;
+       }
+       /* Does not start with '.'. */
+       if (name[0] == '.') {
+               WARN("Name \"%s\" is not allowed to be used in a path since it starts with '.'", name);
+               return false;
+       }
+       /* Does not contain a path-separator. */
+       if (strchr(name, LTTNG_PATH_SEPARATOR)) {
+               WARN("Name \"%s\" is not allowed to be used in a path since it contains a path separator", name);
+               return false;
+       }
+
+       return true;
+}
+
 /*
  * Create a new session by assigning a new session ID.
  *
@@ -240,9 +273,12 @@ struct relay_session *session_create(const char *session_name,
        assert(hostname);
        assert(base_path);
 
-       if (strstr(session_name, ".")) {
-               ERR("Illegal character in session name: \"%s\"",
-                               session_name);
+       if (!is_name_path_safe(session_name)) {
+               ERR("Refusing to create session as the provided session name is not path-safe");
+               goto error;
+       }
+       if (!is_name_path_safe(hostname)) {
+               ERR("Refusing to create session as the provided hostname is not path-safe");
                goto error;
        }
        if (strstr(base_path, "../")) {
@@ -250,11 +286,6 @@ struct relay_session *session_create(const char *session_name,
                                base_path);
                goto error;
        }
-       if (strstr(hostname, ".")) {
-               ERR("Invalid character in hostname: \"%s\"",
-                               hostname);
-               goto error;
-       }
 
        session = zmalloc(sizeof(*session));
        if (!session) {
@@ -531,8 +562,8 @@ void print_sessions(void)
        rcu_read_unlock();
 }
 
-int session_init_output_directory_handle(struct relay_session *session,
-               struct lttng_directory_handle *handle)
+struct lttng_directory_handle *session_create_output_directory_handle(
+               struct relay_session *session)
 {
        int ret;
        /*
@@ -540,11 +571,11 @@ int session_init_output_directory_handle(struct relay_session *session,
         * e.g. /home/user/lttng-traces/hostname/session_name
         */
        char *full_session_path = NULL;
+       struct lttng_directory_handle *handle = NULL;
 
        pthread_mutex_lock(&session->lock);
        full_session_path = create_output_path(session->output_path);
        if (!full_session_path) {
-               ret = -1;
                goto end;
        }
 
@@ -556,12 +587,9 @@ int session_init_output_directory_handle(struct relay_session *session,
                goto end;
        }
 
-       ret = lttng_directory_handle_init(handle, full_session_path);
-       if (ret) {
-               goto end;
-       }
+       handle = lttng_directory_handle_create(full_session_path);
 end:
        pthread_mutex_unlock(&session->lock);
        free(full_session_path);
-       return ret;
+       return handle;
 }