From 8aa6e81f43c652ccf337910e8803cb69022f3e46 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matthias=20G=C3=B6rgens?= Date: Tue, 13 Sep 2022 21:14:35 +0800 Subject: [PATCH] gh-96678: Fix UB of null pointer arithmetic (GH-96782) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Automerge-Triggered-By: GH:pablogsal (cherry picked from commit 81e36f350b75d2ed2668825f7df6e059b57f859c) Co-authored-by: Matthias Görgens --- .../2022-09-13-12-06-46.gh-issue-96678.NqGFyb.rst | 1 + Parser/tokenizer.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-09-13-12-06-46.gh-issue-96678.NqGFyb.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-09-13-12-06-46.gh-issue-96678.NqGFyb.rst b/Misc/NEWS.d/next/Core and Builtins/2022-09-13-12-06-46.gh-issue-96678.NqGFyb.rst new file mode 100644 index 00000000000000..bdd33c8d2ca914 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2022-09-13-12-06-46.gh-issue-96678.NqGFyb.rst @@ -0,0 +1 @@ +Fix undefined behaviour in C code of null pointer arithmetic. diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c index 8d9fbf5cf9596a..a5cfb659b430a4 100644 --- a/Parser/tokenizer.c +++ b/Parser/tokenizer.c @@ -1542,7 +1542,7 @@ tok_get(struct tok_state *tok, const char **p_start, const char **p_end) } while (c == ' ' || c == '\t' || c == '\014'); /* Set start of current token */ - tok->start = tok->cur - 1; + tok->start = tok->cur == NULL ? NULL : tok->cur - 1; /* Skip comment, unless it's a type comment */ if (c == '#') {