various fixes

src/libcrun/linux.c

@@ -1144,7 +1144,7 @@ static int
 mount_masked_dir (libcrun_container_t *container, int pathfd, const char *rel_path, libcrun_error_t *err)
 {
   struct private_data_s *private_data = get_private_data (container);
-  cleanup_close int mountfd = -1;
+  cleanup_close int newfd = -1;
   libcrun_error_t tmp_err = NULL;
   int ret;
 
@@ -1160,37 +1160,42 @@ mount_masked_dir (libcrun_container_t *container, int pathfd, const char *rel_pa
       goto fallback_to_tmpfs;
     }
 
-  mountfd = private_data->maskdir_fd;
-  if (mountfd >= 0)
+  if (private_data->maskdir_fd >= 0)
     {
-      int rootfsfd = get_private_data (container)->rootfsfd;
+      int rootfsfd = private_data->rootfsfd;
       struct stat before, after;
 
-      ret = fstat (mountfd, &before);
+      ret = fstat (private_data->maskdir_fd, &before);
       if (UNLIKELY (ret < 0))
         return crun_make_error (err, errno, "fstat masked dir `%s`", rel_path);
 
-      ret = fs_move_mount_to (mountfd, pathfd, NULL);
+      ret = fs_move_mount_to (private_data->maskdir_fd, pathfd, NULL);
       if (LIKELY (ret == 0))
         {
-          mountfd = get_bind_mount (rootfsfd, rel_path, true, true, false, MS_PRIVATE, err);
-          if (UNLIKELY (mountfd < 0))
-            return mountfd;
+          newfd = get_bind_mount (rootfsfd, rel_path, true, true, false, MS_PRIVATE, err);
+          if (UNLIKELY (newfd < 0))
+            return newfd;
 
-          ret = fstat (mountfd, &after);
+          ret = fstat (newfd, &after);
           if (UNLIKELY (ret < 0))
             return crun_make_error (err, errno, "fstat masked dir `%s`", rel_path);
 
           if (before.st_dev != after.st_dev || before.st_ino != after.st_ino)
             return crun_make_error (err, 0, "race condition detected remounting masked path `/%s`", rel_path);
 
           TEMP_FAILURE_RETRY (close (private_data->maskdir_fd));
-          private_data->maskdir_fd = mountfd;
-          mountfd = -1;
+          private_data->maskdir_fd = newfd;
+          newfd = -1;
 
           return 0;
         }
 
+      {
+        int move_errno = errno;
+        crun_error_release (&tmp_err);
+        crun_make_error (&tmp_err, move_errno, "move mount masked dir `%s`", rel_path);
+      }
+
       TEMP_FAILURE_RETRY (close (private_data->maskdir_fd));
       private_data->maskdir_fd = -1;
     }

src/libcrun/utils.c

@@ -815,7 +815,7 @@ libcrun_initialize_apparmor (libcrun_error_t *err)
 {
   cleanup_close int fd = -1;
   int size;
-  char buf[2];
+  char buf[1];
 
   if (apparmor_enabled >= 0)
     return apparmor_enabled;
@@ -832,7 +832,7 @@ libcrun_initialize_apparmor (libcrun_error_t *err)
       return crun_make_error (err, errno, "open `/sys/module/apparmor/parameters/enabled`");
     }
 
-  size = TEMP_FAILURE_RETRY (read (fd, buf, 2));
+  size = TEMP_FAILURE_RETRY (read (fd, buf, sizeof (buf)));
 
   apparmor_enabled = size > 0 && buf[0] == 'Y' ? 1 : 0;
 
@@ -963,9 +963,12 @@ libcrun_is_apparmor_enabled (libcrun_error_t *err)
 static int
 is_current_process_confined (libcrun_container_t *container, libcrun_error_t *err)
 {
+#define UNCONFINED "unconfined"
+#define UNCONFINED_LEN (ssize_t) (sizeof (UNCONFINED) - 1)
   cleanup_free const char *attr_path = lsm_attr_path (container, "apparmor", "current", err);
   cleanup_close int fd = -1;
-  char buf[256];
+  /* Only the "unconfined" token plus one delimiter byte are inspected.  */
+  char buf[UNCONFINED_LEN + 1];
 
   if (UNLIKELY (attr_path == NULL))
     return -1;
@@ -977,13 +980,22 @@ is_current_process_confined (libcrun_container_t *container, libcrun_error_t *er
   if (UNLIKELY (check_proc_super_magic (fd, attr_path, err)))
     return -1;
 
-  ssize_t bytes_read = read (fd, buf, sizeof (buf) - 1);
+  ssize_t bytes_read = TEMP_FAILURE_RETRY (read (fd, buf, sizeof (buf)));
   if (UNLIKELY (bytes_read < 0))
     return crun_make_error (err, errno, "read from `%s`", attr_path);
 
-#define UNCONFINED "unconfined"
-#define UNCONFINED_LEN (ssize_t) (sizeof (UNCONFINED) - 1)
-  return bytes_read >= UNCONFINED_LEN && memcmp (buf, UNCONFINED, UNCONFINED_LEN);
+  /* The process is unconfined only when the attribute is exactly the token
+     "unconfined", optionally followed by a delimiter.  Anything shorter (a
+     short read), or a longer profile name such as "unconfined_foo", means the
+     process is confined.  When in doubt default to confined, which is the safe
+     assumption for the caller.  */
+  if (bytes_read < UNCONFINED_LEN || memcmp (buf, UNCONFINED, UNCONFINED_LEN) != 0)
+    return 1;
+  if (bytes_read == UNCONFINED_LEN || buf[UNCONFINED_LEN] == '\n' || buf[UNCONFINED_LEN] == ' ')
+    return 0;
+  return 1;
+#undef UNCONFINED
+#undef UNCONFINED_LEN
 }
 
 int