[Python-checkins] bpo-36495: Fix two out-of-bounds array reads (GH-12641)

[Guido van Rossum]

https://github.com/python/cpython/commit/a4d78362397fc3bced6ea80fbc7b5f4827aec55e
commit: a4d78362397fc3bced6ea80fbc7b5f4827aec55e
branch: master
author: Brad Larsen <brad at bradfordlarsen.com>
committer: Guido van Rossum <guido at python.org>
date: 2019-04-01T07:36:05-07:00
summary:

bpo-36495: Fix two out-of-bounds array reads (GH-12641)

Research and fix by @bradlarsen.

files:
M Python/ast.c

diff --git a/Python/ast.c b/Python/ast.c
index e9154fecff06..913e53ad7937 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1400,7 +1400,7 @@ handle_keywordonly_args(struct compiling *c, const node *n, int start,
                     goto error;
                 asdl_seq_SET(kwonlyargs, j++, arg);
                 i += 1; /* the name */
-                if (TYPE(CHILD(n, i)) == COMMA)
+                if (i < NCH(n) && TYPE(CHILD(n, i)) == COMMA)
                     i += 1; /* the comma, if present */
                 break;
             case TYPE_COMMENT:
@@ -1599,7 +1599,7 @@ ast_for_arguments(struct compiling *c, const node *n)
                 if (!kwarg)
                     return NULL;
                 i += 2; /* the double star and the name */
-                if (TYPE(CHILD(n, i)) == COMMA)
+                if (i < NCH(n) && TYPE(CHILD(n, i)) == COMMA)
                     i += 1; /* the comma, if present */
                 break;
             case TYPE_COMMENT: