fix: stop parsing printf buffer after invalid string index

- IGC stores invalid string index at the end of printf buffer,
invalid index is equal to (int32_t)-1 extended to (char*)
- printKernelOutput() should not parse buffer after invalid index was
found to avoid invalid string pointer dereference

Related-To: NEO-5753

Signed-off-by: Mateusz Hoppe <mateusz.hoppe@intel.com>

shared/source/program/print_formatter.cpp

@@ -45,6 +45,9 @@ void PrintFormatter::printKernelOutput(const std::function<void(char *)> &print)
         while (currentOffset + sizeof(char *) <= printfOutputBufferSize) {
             char *formatString = nullptr;
             read(&formatString);
+            if (formatString == reinterpret_cast<char *>(static_cast<uintptr_t>(0xffffffff))) {
+                break;
+            }
             if (formatString != nullptr) {
                 printString(formatString, print);
             }

shared/test/unit_test/program/printf_helper_tests.cpp

@@ -985,6 +985,25 @@ TEST_F(PrintFormatterTest, GivenNoStringMapAndBufferWithFormatStringAnd2StringsT
     EXPECT_STREQ(expectedOutput, output);
 }
 
+TEST_F(PrintFormatterTest, GivenNoStringMapAndInvalidStringIndexStoredWhenPrintingOutputThenBufferParsingStopsAfterInvalidIndex) {
+    printFormatter.reset(new PrintFormatter(static_cast<uint8_t *>(data->getUnderlyingBuffer()), printfBufferSize, true));
+
+    const char *string1 = "str1";
+    storeData(string1);
+    const int invalidIndex = -1;
+    const int zero = 0;
+    storeData(invalidIndex);
+    storeData(zero);
+
+    const char *string2 = "str2";
+    storeData(string2);
+
+    const char *expectedOutput = "str1";
+    char output[maxPrintfOutputLength];
+    printFormatter->printKernelOutput([&output](char *str) { strncpy_s(output, maxPrintfOutputLength, str, maxPrintfOutputLength - 1); });
+    EXPECT_STREQ(expectedOutput, output);
+}
+
 TEST_F(PrintFormatterTest, GivenTypeSmallerThan4BThenItIsReadAs4BValue) {
     printFormatter.reset(new PrintFormatter(static_cast<uint8_t *>(data->getUnderlyingBuffer()), printfBufferSize, true));
     const char *formatString = "%c %hd %d";