Fix potential buffer overflows when calling sprintf

1. Replace sprintf with snprintf, which is safer
2. An unsigned int or unsigned long int requires 11 bytes to print
   (including the null terminator)
3. Use PRIu16 macro to print uint16_t
4. Format string "#%2d %2d:%02d:%02d.%02d\n" in
   StopWatch::stopLapBtnEventHandler() requires at least 17 bytes.
   The 16-byte buffer would clearly be overrun if sprintf were used.

5 files changed, 11 insertions, 11 deletions

diff --git a/src/components/datetime/DateTimeController.cpp b/src/components/datetime/DateTimeController.cpp
index 9e9fb6e4..8d4a834e 100644
--- a/src/components/datetime/DateTimeController.cpp
+++ b/src/components/datetime/DateTimeController.cpp
@@ -140,9 +140,9 @@ std::string DateTime::FormattedTime() {
       hour12 = (hour == 12) ? 12 : hour - 12;
       amPmStr = "PM";
     }
-    sprintf(buff, "%i:%02i %s", hour12, minute, amPmStr);
+    snprintf(buff, sizeof(buff), "%i:%02i %s", hour12, minute, amPmStr);
   } else {
-    sprintf(buff, "%02i:%02i", hour, minute);
+    snprintf(buff, sizeof(buff), "%02i:%02i", hour, minute);
   }
   return std::string(buff);
 }
diff --git a/src/displayapp/screens/StopWatch.cpp b/src/displayapp/screens/StopWatch.cpp
index 239ebe39..d2b81154 100644
--- a/src/displayapp/screens/StopWatch.cpp
+++ b/src/displayapp/screens/StopWatch.cpp
@@ -198,11 +198,11 @@ void StopWatch::stopLapBtnEventHandler() {
         continue;
       }
       TimeSeparated_t times = convertTicksToTimeSegments(laps[i]);
-      char buffer[16];
+      char buffer[17];
       if (times.hours == 0) {
-        sprintf(buffer, "#%2d   %2d:%02d.%02d\n", i + 1, times.mins, times.secs, times.hundredths);
+        snprintf(buffer, sizeof(buffer), "#%2d   %2d:%02d.%02d\n", i + 1, times.mins, times.secs, times.hundredths);
       } else {
-        sprintf(buffer, "#%2d %2d:%02d:%02d.%02d\n", i + 1, times.hours, times.mins, times.secs, times.hundredths);
+        snprintf(buffer, sizeof(buffer), "#%2d %2d:%02d:%02d.%02d\n", i + 1, times.hours, times.mins, times.secs, times.hundredths);
       }
       lv_label_ins_text(lapText, LV_LABEL_POS_LAST, buffer);
     }
diff --git a/src/displayapp/screens/SystemInfo.cpp b/src/displayapp/screens/SystemInfo.cpp
index eea75938..18fb7ad2 100644
--- a/src/displayapp/screens/SystemInfo.cpp
+++ b/src/displayapp/screens/SystemInfo.cpp
@@ -236,9 +236,9 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen4() {
   auto nb = uxTaskGetSystemState(tasksStatus, maxTaskCount, nullptr);
   std::sort(tasksStatus, tasksStatus + nb, sortById);
   for (uint8_t i = 0; i < nb && i < maxTaskCount; i++) {
-    char buffer[7] = {0};
+    char buffer[11] = {0};
 
-    sprintf(buffer, "%lu", tasksStatus[i].xTaskNumber);
+    snprintf(buffer, sizeof(buffer), "%lu", tasksStatus[i].xTaskNumber);
     lv_table_set_cell_value(infoTask, i + 1, 0, buffer);
     switch (tasksStatus[i].eCurrentState) {
       case eReady:
@@ -262,9 +262,9 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen4() {
     lv_table_set_cell_value(infoTask, i + 1, 1, buffer);
     lv_table_set_cell_value(infoTask, i + 1, 2, tasksStatus[i].pcTaskName);
     if (tasksStatus[i].usStackHighWaterMark < 20) {
-      sprintf(buffer, "%d low", tasksStatus[i].usStackHighWaterMark);
+      snprintf(buffer, sizeof(buffer), "%" PRIu16 " low", tasksStatus[i].usStackHighWaterMark);
     } else {
-      sprintf(buffer, "%d", tasksStatus[i].usStackHighWaterMark);
+      snprintf(buffer, sizeof(buffer), "%" PRIu16, tasksStatus[i].usStackHighWaterMark);
     }
     lv_table_set_cell_value(infoTask, i + 1, 3, buffer);
   }
diff --git a/src/displayapp/screens/Twos.cpp b/src/displayapp/screens/Twos.cpp
index 8157a160..6f2eff40 100644
--- a/src/displayapp/screens/Twos.cpp
+++ b/src/displayapp/screens/Twos.cpp
@@ -242,7 +242,7 @@ void Twos::updateGridDisplay() {
     const unsigned int col = i % nCols;
     if (grid[row][col].value > 0) {
       char buffer[7];
-      sprintf(buffer, "%d", grid[row][col].value);
+      snprintf(buffer, sizeof(buffer), "%u", grid[row][col].value);
       lv_table_set_cell_value(gridDisplay, row, col, buffer);
     } else {
       lv_table_set_cell_value(gridDisplay, row, col, "");
diff --git a/src/displayapp/screens/settings/SettingDisplay.cpp b/src/displayapp/screens/settings/SettingDisplay.cpp
index 91f4d590..9abb4c74 100644
--- a/src/displayapp/screens/settings/SettingDisplay.cpp
+++ b/src/displayapp/screens/settings/SettingDisplay.cpp
@@ -46,7 +46,7 @@ SettingDisplay::SettingDisplay(Pinetime::Applications::DisplayApp* app, Pinetime
   char buffer[12];
   for (unsigned int i = 0; i < options.size(); i++) {
     cbOption[i] = lv_checkbox_create(container1, nullptr);
-    sprintf(buffer, "%2ds", options[i] / 1000);
+    snprintf(buffer, sizeof(buffer), "%2" PRIu16 "s", options[i] / 1000);
     lv_checkbox_set_text(cbOption[i], buffer);
     cbOption[i]->user_data = this;
     lv_obj_set_event_cb(cbOption[i], event_handler);