- Change a check of securelevel to securelevel_gt() call in order to help

  against users within a jail attempting to load kernel modules.
- Add a check of securelevel_gt() to vfs_mount() in order to chop some
  low hanging fruit for the repair of securelevel checking of linking and
  unlinking files from within jails.  There is more to be done here.

Reviewed by: rwatson

1 files changed, 5 insertions, 0 deletions

diff --git a/sys/kern/vfs_extattr.c b/sys/kern/vfs_extattr.c
index 915e26a..8247f8d 100644
--- a/sys/kern/vfs_extattr.c
+++ b/sys/kern/vfs_extattr.c
@@ -307,6 +307,11 @@ vfs_mount(td, fstype, fspath, fsflags, fsdata)
 			vput(vp);
 			return error;
 		}
+		error = securelevel_gt(td->td_ucred, 0);
+		if (error == 0) {
+			vput(vp);
+			return (EPERM);
+		}
 		error = linker_load_file(fstype, &lf);
 		if (error || lf == NULL) {
 			vput(vp);