merge revision(s) 0846c2da457e7523819236ac7da492029b3ef73d,6c7cb00c094332a208cf36e5cd723a9ba60c41b8: [Backport #16376]

	Check backref number buffer overrun [Bug #16376]

	---
	 regcomp.c                | 21 ++++++++++++---------
	 test/ruby/test_regexp.rb |  6 ++++++
	 2 files changed, 18 insertions(+), 9 deletions(-)

	test/ruby/test_regexp.rb: Avoid "ambiguity between regexp and two
	 divisions"

	---
	 test/ruby/test_regexp.rb | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

3 files changed, 19 insertions, 10 deletions

diff --git a/regcomp.c b/regcomp.c
index df7f73bac5..00d3746348 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -1914,7 +1914,7 @@ noname_disable_map(Node** plink, GroupNumRemap* map, int* counter)
 }
 
 static int
-renumber_node_backref(Node* node, GroupNumRemap* map)
+renumber_node_backref(Node* node, GroupNumRemap* map, const int num_mem)
 {
   int i, pos, n, old_num;
   int *backs;
@@ -1930,6 +1930,7 @@ renumber_node_backref(Node* node, GroupNumRemap* map)
     backs = bn->back_dynamic;
 
   for (i = 0, pos = 0; i < old_num; i++) {
+    if (backs[i] > num_mem)  return ONIGERR_INVALID_BACKREF;
     n = map[backs[i]].new_val;
     if (n > 0) {
       backs[pos] = n;
@@ -1942,7 +1943,7 @@ renumber_node_backref(Node* node, GroupNumRemap* map)
 }
 
 static int
-renumber_by_map(Node* node, GroupNumRemap* map)
+renumber_by_map(Node* node, GroupNumRemap* map, const int num_mem)
 {
   int r = 0;
 
@@ -1950,28 +1951,30 @@ renumber_by_map(Node* node, GroupNumRemap* map)
   case NT_LIST:
   case NT_ALT:
     do {
-      r = renumber_by_map(NCAR(node), map);
+      r = renumber_by_map(NCAR(node), map, num_mem);
     } while (r == 0 && IS_NOT_NULL(node = NCDR(node)));
     break;
   case NT_QTFR:
-    r = renumber_by_map(NQTFR(node)->target, map);
+    r = renumber_by_map(NQTFR(node)->target, map, num_mem);
     break;
   case NT_ENCLOSE:
     {
       EncloseNode* en = NENCLOSE(node);
-      if (en->type == ENCLOSE_CONDITION)
+      if (en->type == ENCLOSE_CONDITION) {
+	if (en->regnum > num_mem)  return ONIGERR_INVALID_BACKREF;
 	en->regnum = map[en->regnum].new_val;
-      r = renumber_by_map(en->target, map);
+      }
+      r = renumber_by_map(en->target, map, num_mem);
     }
     break;
 
   case NT_BREF:
-    r = renumber_node_backref(node, map);
+    r = renumber_node_backref(node, map, num_mem);
     break;
 
   case NT_ANCHOR:
     if (NANCHOR(node)->target)
-      r = renumber_by_map(NANCHOR(node)->target, map);
+      r = renumber_by_map(NANCHOR(node)->target, map, num_mem);
     break;
 
   default:
@@ -2033,7 +2036,7 @@ disable_noname_group_capture(Node** root, regex_t* reg, ScanEnv* env)
   r = noname_disable_map(root, map, &counter);
   if (r != 0) return r;
 
-  r = renumber_by_map(*root, map);
+  r = renumber_by_map(*root, map, env->num_mem);
   if (r != 0) return r;
 
   for (i = 1, pos = 1; i <= env->num_mem; i++) {
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 5c7d205185..8709d05752 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -1293,6 +1293,12 @@ class TestRegexp < Test::Unit::TestCase
     assert_nil($1)
   end
 
+  def test_backref_overrun
+    assert_raise_with_message(SyntaxError, /invalid backref number/) do
+      eval(%["".match(/(())(?<X>)((?(90000)))/)])
+    end
+  end
+
   # This assertion is for porting x2() tests in testpy.py of Onigmo.
   def assert_match_at(re, str, positions, msg = nil)
     re = Regexp.new(re) unless re.is_a?(Regexp)
diff --git a/version.h b/version.h
index cf0de1076e..dc3d527107 100644
--- a/version.h
+++ b/version.h
@@ -2,7 +2,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 6
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 207
+#define RUBY_PATCHLEVEL 208
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 12