diff options
authorMarc Mutz <>2020-05-08 22:46:44 +0200
committerMarc Mutz <>2020-05-09 08:24:39 +0200
commitf6b96bc34749e4478e75c081bbd0af406cd737b5 (patch)
parentc3b5efa250ee29413d348fea96e11b7e6f94e54f (diff)
QString: fix UB in replace()
Comparing with <, >, <= or >= such pointers as are not pointing into the same array is UB. A clever compiler could look at the code, determine that the only valid execution is for it to return true, and just always take the copy. While that would be benign, it's not guaranteed that this would be the outcome (it's UB, after all), and, of course, we don't want to take the performance hit if we don't need it. Pick-to: 5.15 Change-Id: I48cda232ff10a3c9fd4babcd7e7103a3aed126e8 Reviewed-by: Ville Voutilainen <>
1 files changed, 2 insertions, 1 deletions
diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index fea5fb00df..49ddb9279b 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -3038,7 +3038,8 @@ QChar *textCopy(const QChar *start, int len)
bool pointsIntoRange(const QChar *ptr, const ushort *base, int len)
const QChar *const start = reinterpret_cast<const QChar *>(base);
- return start <= ptr && ptr < start + len;
+ const std::less<const QChar *> less;
+ return !less(ptr, start) && less(ptr, start + len);
} // end namespace