aarch64: Fix missing BTI protection from dependencies [BZ #26926]

The _dl_open_check and _rtld_main_check hooks are not called on the
dependencies of a loaded module, so BTI protection was missed on
every module other than the main executable and directly dlopened
libraries.

The fix just iterates over dependencies to enable BTI.

Fixes bug 26926.

diff --git a/sysdeps/aarch64/dl-bti.c b/sysdeps/aarch64/dl-bti.c
index 196e462520e0dc49bac57996eaaac5972635204e..56c097210ad4968ba40e1366f5925a845f15d4a0 100644 (file)
--- a/sysdeps/aarch64/dl-bti.c
+++ b/sysdeps/aarch64/dl-bti.c
@@ -51,11 +51,24 @@ enable_bti (struct link_map *map, const char *program)
   return 0;
 }
 
-/* Enable BTI for L if required.  */
+/* Enable BTI for L and its dependencies.  */
 
 void
 _dl_bti_check (struct link_map *l, const char *program)
 {
-  if (GLRO(dl_aarch64_cpu_features).bti && l->l_mach.bti)
+  if (!GLRO(dl_aarch64_cpu_features).bti)
+    return;
+
+  if (l->l_mach.bti)
     enable_bti (l, program);
+
+  unsigned int i = l->l_searchlist.r_nlist;
+  while (i-- > 0)
+    {
+      struct link_map *dep = l->l_initfini[i];
+      if (dep->l_init_called)
+       continue;
+      if (dep->l_mach.bti)
+       enable_bti (dep, program);
+    }
 }