[vim] 27/139: patch 7.4.1715 Problem: Double free when a partial is in a cycle with a list or dict. (Nikolai Pavlov) Solution: Do not free a nested list or dict used by the partial.

[James McCoy]

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jamessan pushed a commit to branch debian/sid
in repository vim.

commit ddecc25947dbdd689d5bcaed32f298a08abdd497
Author: Bram Moolenaar <Bram at vim.org>
Date:   Wed Apr 6 22:59:37 2016 +0200

    patch 7.4.1715
    Problem:    Double free when a partial is in a cycle with a list or dict.
                (Nikolai Pavlov)
    Solution:   Do not free a nested list or dict used by the partial.
---
 src/eval.c                   | 110 ++++++++++++++++++++++++++-----------------
 src/testdir/test_partial.vim |  18 +++++++
 src/version.c                |   2 +
 3 files changed, 88 insertions(+), 42 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index 070485f..e7fbeaa 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5929,6 +5929,57 @@ get_lit_string_tv(char_u **arg, typval_T *rettv, int evaluate)
     return OK;
 }
 
+    static void
+partial_free(partial_T *pt, int recursive)
+{
+    int i;
+
+    for (i = 0; i < pt->pt_argc; ++i)
+    {
+	typval_T *tv = &pt->pt_argv[i];
+
+	if (recursive || (tv->v_type != VAR_DICT && tv->v_type != VAR_LIST))
+	    clear_tv(tv);
+    }
+    vim_free(pt->pt_argv);
+    if (recursive)
+	dict_unref(pt->pt_dict);
+    func_unref(pt->pt_name);
+    vim_free(pt->pt_name);
+    vim_free(pt);
+}
+
+/*
+ * Unreference a closure: decrement the reference count and free it when it
+ * becomes zero.
+ */
+    void
+partial_unref(partial_T *pt)
+{
+    if (pt != NULL && --pt->pt_refcount <= 0)
+	partial_free(pt, TRUE);
+}
+
+/*
+ * Like clear_tv(), but do not free lists or dictionaries.
+ * This is when called via free_unref_items().
+ */
+    static void
+clear_tv_no_recurse(typval_T *tv)
+{
+    if (tv->v_type == VAR_PARTIAL)
+    {
+	partial_T *pt = tv->vval.v_partial;
+
+	/* We unref the partial but not the dict or any list it
+	 * refers to. */
+	if (pt != NULL && --pt->pt_refcount == 0)
+	    partial_free(pt, FALSE);
+    }
+    else if (tv->v_type != VAR_LIST && tv->v_type != VAR_DICT)
+	clear_tv(tv);
+}
+
 /*
  * Allocate a variable for a List and fill it from "*arg".
  * Return OK or FAIL.
@@ -6070,9 +6121,10 @@ list_free(
     {
 	/* Remove the item before deleting it. */
 	l->lv_first = item->li_next;
-	if (recurse || (item->li_tv.v_type != VAR_LIST
-					   && item->li_tv.v_type != VAR_DICT))
+	if (recurse)
 	    clear_tv(&item->li_tv);
+	else
+	    clear_tv_no_recurse(&item->li_tv);
 	vim_free(item);
     }
     vim_free(l);
@@ -7185,6 +7237,16 @@ set_ref_in_item(
 		}
 	    }
 	}
+	if (tv->v_type == VAR_PARTIAL)
+	{
+	    partial_T	*pt = tv->vval.v_partial;
+	    int		i;
+
+	    if (pt != NULL)
+		for (i = 0; i < pt->pt_argc; ++i)
+		    set_ref_in_item(&pt->pt_argv[i], copyID,
+							ht_stack, list_stack);
+	}
     }
     else if (tv->v_type == VAR_LIST)
     {
@@ -7215,32 +7277,6 @@ set_ref_in_item(
     return abort;
 }
 
-    static void
-partial_free(partial_T *pt, int free_dict)
-{
-    int i;
-
-    for (i = 0; i < pt->pt_argc; ++i)
-	clear_tv(&pt->pt_argv[i]);
-    vim_free(pt->pt_argv);
-    if (free_dict)
-	dict_unref(pt->pt_dict);
-    func_unref(pt->pt_name);
-    vim_free(pt->pt_name);
-    vim_free(pt);
-}
-
-/*
- * Unreference a closure: decrement the reference count and free it when it
- * becomes zero.
- */
-    void
-partial_unref(partial_T *pt)
-{
-    if (pt != NULL && --pt->pt_refcount <= 0)
-	partial_free(pt, TRUE);
-}
-
 /*
  * Allocate an empty header for a dictionary.
  */
@@ -7331,20 +7367,10 @@ dict_free(
 	     * something recursive causing trouble. */
 	    di = HI2DI(hi);
 	    hash_remove(&d->dv_hashtab, hi);
-	    if (recurse || (di->di_tv.v_type != VAR_LIST
-					     && di->di_tv.v_type != VAR_DICT))
-	    {
-		if (!recurse && di->di_tv.v_type == VAR_PARTIAL)
-		{
-		    partial_T *pt = di->di_tv.vval.v_partial;
-
-		    /* We unref the partial but not the dict it refers to. */
-		    if (pt != NULL && --pt->pt_refcount == 0)
-			partial_free(pt, FALSE);
-		}
-		else
-		    clear_tv(&di->di_tv);
-	    }
+	    if (recurse)
+		clear_tv(&di->di_tv);
+	    else
+		clear_tv_no_recurse(&di->di_tv);
 	    vim_free(di);
 	    --todo;
 	}
diff --git a/src/testdir/test_partial.vim b/src/testdir/test_partial.vim
index 08958de..2d53e82 100644
--- a/src/testdir/test_partial.vim
+++ b/src/testdir/test_partial.vim
@@ -220,3 +220,21 @@ func Test_bind_in_python()
     endtry
   endif
 endfunc
+
+" This causes double free on exit if EXITFREE is defined.
+func Test_cyclic_list_arg()
+  let l = []
+  let Pt = function('string', [l])
+  call add(l, Pt)
+  unlet l
+  unlet Pt
+endfunc
+
+" This causes double free on exit if EXITFREE is defined.
+func Test_cyclic_dict_arg()
+  let d = {}
+  let Pt = function('string', [d])
+  let d.Pt = Pt
+  unlet d
+  unlet Pt
+endfunc
diff --git a/src/version.c b/src/version.c
index d420eba..5c89d6b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -749,6 +749,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1715,
+/**/
     1714,
 /**/
     1713,

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