kconfig: delay symbol direct dependency initialization

This fixes the use-after-free and associated crash in kconfig introduced
in commit 246cf9c26bf11f2bffbecea6e5bd222eee7b1df8.

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

2 files changed, 2 insertions, 6 deletions

diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 6ee2e4fb1481..170459c224a1 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -165,7 +165,6 @@ struct menu {
         struct symbol *sym;
         struct property *prompt;
         struct expr *dep;
-        struct expr *dir_dep;
         unsigned int flags;
         char *help;
         struct file *file;
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 4fb590247f33..edda8b49619d 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -107,7 +107,6 @@ static struct expr *menu_check_dep(struct expr *e)
 void menu_add_dep(struct expr *dep)
 {
         current_entry->dep = expr_alloc_and(current_entry->dep, menu_check_dep(dep));
-        current_entry->dir_dep = current_entry->dep;
 }
 
 void menu_set_type(int type)
@@ -291,10 +290,6 @@ void menu_finalize(struct menu *parent)
                 for (menu = parent->list; menu; menu = menu->next)
                         menu_finalize(menu);
         } else if (sym) {
-                /* ignore inherited dependencies for dir_dep */
-                sym->dir_dep.expr = expr_transform(expr_copy(parent->dir_dep));
-                sym->dir_dep.expr = expr_eliminate_dups(sym->dir_dep.expr);
-
                 basedep = parent->prompt ? parent->prompt->visible.expr : NULL;
                 basedep = expr_trans_compare(basedep, E_UNEQUAL, &symbol_no);
                 basedep = expr_eliminate_dups(expr_transform(basedep));
@@ -325,6 +320,8 @@ void menu_finalize(struct menu *parent)
                         parent->next = last_menu->next;
                         last_menu->next = NULL;
                 }
+
+                sym->dir_dep.expr = parent->dep;
         }
         for (menu = parent->list; menu; menu = menu->next) {
                 if (sym && sym_is_choice(sym) &&