From 937a778ea37e129a758c44a3868d3842e5cd62ab Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Sat, 14 Dec 2019 23:18:53 +0100
Subject: [PATCH] re PR preprocessor/92919 (invalid memory access in
wide_str_to_charconst when running ucn2.C testcase (caught by hwasan))
PR preprocessor/92919
* charset.c (wide_str_to_charconst): If str contains just the
NUL terminator, punt quietly.
From-SVN: r279399
---
libcpp/ChangeLog | 6 ++++++
libcpp/charset.c | 11 +++++++++++
2 files changed, 17 insertions(+)
diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 2090bd72103c..69b1c0c49403 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,9 @@
+2019-12-14 Jakub Jelinek <jakub@redhat.com>
+
+ PR preprocessor/92919
+ * charset.c (wide_str_to_charconst): If str contains just the
+ NUL terminator, punt quietly.
+
2019-12-09 David Malcolm <dmalcolm@redhat.com>
* include/line-map.h (label_text::label_text): Make private.
diff --git a/libcpp/charset.c b/libcpp/charset.c
index 956d2dad5c86..a638a1b98fa0 100644
--- a/libcpp/charset.c
+++ b/libcpp/charset.c
@@ -1970,6 +1970,17 @@ wide_str_to_charconst (cpp_reader *pfile, cpp_string str,
size_t off, i;
cppchar_t result = 0, c;
+ if (str.len <= nbwc)
+ {
+ /* Error recovery, if no errors have been diagnosed previously,
+ there should be at least two wide characters. Empty literals
+ are diagnosed earlier and we can get just the zero terminator
+ only if there were errors diagnosed during conversion. */
+ *pchars_seen = 0;
+ *unsignedp = 0;
+ return 0;
+ }
+
/* This is finicky because the string is in the target's byte order,
which may not be our byte order. Only the last character, ignoring
the NUL terminator, is relevant. */
--
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