sync with upstream luatex; sync with upstream metapost.

git-svn-id: svn://tug.org/texlive/trunk@59144 c570f23f-e606-0410-a88d-b1316a301751

2 files changed, 10 insertions, 2 deletions

diff --git a/Build/source/texk/web2c/mplibdir/ChangeLog b/Build/source/texk/web2c/mplibdir/ChangeLog
index 3a421c77907..1ad10d39285 100644
--- a/Build/source/texk/web2c/mplibdir/ChangeLog
+++ b/Build/source/texk/web2c/mplibdir/ChangeLog
@@ -1,3 +1,7 @@
+2021-05-09  Luigi Scarso  <luigi.scarso@gmail.com>
+	* Impose mp->stack_size < 1001 in @d push_input to avoid stack overflow 
+          due infinite recursion of macro expansion (thanks to A. Kakuto).
+
 2021-04-10  Luigi Scarso  <luigi.scarso@gmail.com>
 	* Metapost version 2.01 (needed to mark the patch mpx_copy_mpto).
 
diff --git a/Build/source/texk/web2c/mplibdir/mp.w b/Build/source/texk/web2c/mplibdir/mp.w
index 2a28640c215..acb64feed7f 100644
--- a/Build/source/texk/web2c/mplibdir/mp.w
+++ b/Build/source/texk/web2c/mplibdir/mp.w
@@ -18136,11 +18136,15 @@ new level (having, initially, the same properties as the old).
 @d push_input  { /* enter a new input level, save the old */
   if ( mp->input_ptr>mp->max_in_stack ) {
     mp->max_in_stack=mp->input_ptr;
-    if ( mp->input_ptr==mp->stack_size ) {
+    /* The mp->stack_size < 1001 condition is necessary to prevent stack overflow due infinite recursion. */
+    if ( mp->input_ptr==mp->stack_size && mp->stack_size < 1001) {
       int l = (mp->stack_size+(mp->stack_size/4));
       XREALLOC(mp->input_stack, l, in_state_record);
       mp->stack_size = l;
-    }
+    } else {
+      fprintf(stderr, "input stack overflow\n");
+      exit(EXIT_FAILURE);
+   }
   }
   mp->input_stack[mp->input_ptr]=mp->cur_input; /* stack the record */
   incr(mp->input_ptr);