sdpscanner: fix potential unwanted truncation for SDP_TEXT_STR{8,16,32}

QByteArray::resize() treats all negative parameters as a request for
a zero length. So the code

  text.resize(text.indexOf('\0'));

can completely erase the text if there is no '\0' in it.

Fix it by explicitly checking the return value of QByteArray::indexOf().

Change-Id: Idc42bf4b96a9be5b007916263d6cf1e831b96c07
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
(cherry picked from commit 58cb7eeea5c05e42efc806716eb5eb39bd25787b)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/tools/sdpscanner/main.cpp b/src/tools/sdpscanner/main.cpp
index 1f62d2a7..d0c3e2cc 100644
--- a/src/tools/sdpscanner/main.cpp
+++ b/src/tools/sdpscanner/main.cpp
@@ -123,7 +123,9 @@ static void parseAttributeValues(sdp_data_t *data, int indentation, QByteArray &
                 break;
             } else if (!isprint(text[i])) {
                 hasNonPrintableChar = true;
-                text.resize(text.indexOf('\0')); // cut trailing content
+                const auto firstNullIdx = text.indexOf('\0');
+                if (firstNullIdx > 0)
+                    text.resize(firstNullIdx); // cut trailing content
                 break;
             }
         }