Description: fix buffer overflow in XBM parser

Origin: upstream, https://code.qt.io/cgit/qt/qtbase.git/commit/?id=1616c71921b73b22

Last-Update: 2020-08-18

---

 src/gui/image/qxbmhandler.cpp |    4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/src/gui/image/qxbmhandler.cpp

+++ b/src/gui/image/qxbmhandler.cpp

@@ -154,7 +154,9 @@ static bool read_xbm_body(QIODevice *dev

     w = (w+7)/8;                                // byte width

     while (y < h) {                                // for all encoded bytes...

-        if (p) {                                // p = "0x.."

+        if (p && p < (buf + readBytes - 3)) {      // p = "0x.."

+            if (!isxdigit(p[2]) || !isxdigit(p[3]))

+                return false;

             *b++ = hex2byte(p+2);

             p += 2;

             if (++x == w && ++y < h) {