Qt: Fix null pointer dereference

Rework existing code to avoid unsafe localtime

Change-Id: I266ae7e006c6aeed42af39fea07c888874d0f588
Reviewed-on: https://code.wireshark.org/review/34329
Petri-Dish: Roland Knall <rknall@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Roland Knall <rknall@gmail.com>

1 files changed, 17 insertions, 45 deletions

diff --git a/ui/qt/utils/wireshark_zip_helper.cpp b/ui/qt/utils/wireshark_zip_helper.cpp
index 88e13cf098..f2035dda53 100644
--- a/ui/qt/utils/wireshark_zip_helper.cpp
+++ b/ui/qt/utils/wireshark_zip_helper.cpp
@@ -148,58 +148,30 @@ bool WireSharkZipHelper::unzip(QString zipFile, QString directory, bool (*fileCh
 #define UINT32_MAX  (0xffffffff)
 #endif
 
-/* The following methods are being taken from https://github.com/nmoinvaz/minizip/blob/1.2/minishared.c */
-int invalid_date(const struct tm *ptm)
+unsigned long qDateToDosDate(QDateTime time)
 {
-#define datevalue_in_range(min, max, value) ((min) <= (value) && (value) <= (max))
-    return (!datevalue_in_range(0, 207, ptm->tm_year) ||
-            !datevalue_in_range(0, 11, ptm->tm_mon) ||
-            !datevalue_in_range(1, 31, ptm->tm_mday) ||
-            !datevalue_in_range(0, 23, ptm->tm_hour) ||
-            !datevalue_in_range(0, 59, ptm->tm_min) ||
-            !datevalue_in_range(0, 59, ptm->tm_sec));
-#undef datevalue_in_range
-}
+    QDate ld = time.toLocalTime().date();
 
-uint32_t tm_to_dosdate(const struct tm *ptm)
-{
-    struct tm fixed_tm;
-
-    /* Years supported:
-    * [00, 79]      (assumed to be between 2000 and 2079)
-    * [80, 207]     (assumed to be between 1980 and 2107, typical output of old
-                     software that does 'year-1900' to get a double digit year)
-    * [1980, 2107]  (due to the date format limitations, only years between 1980 and 2107 can be stored.)
-    */
-
-    memcpy(&fixed_tm, ptm, sizeof(struct tm));
-    if (fixed_tm.tm_year >= 1980) /* range [1980, 2107] */
-        fixed_tm.tm_year -= 1980;
-    else if (fixed_tm.tm_year >= 80) /* range [80, 99] */
-        fixed_tm.tm_year -= 80;
-    else /* range [00, 79] */
-        fixed_tm.tm_year += 20;
-
-    if (invalid_date(ptm))
-        return 0;
+    int year = ld.year() - 1900;
+    if ( year >= 1980 )
+        year -= 1980;
+    else if ( year >= 80 )
+        year -= 80;
+    else
+        year += 20;
 
-    return (uint32_t)(((fixed_tm.tm_mday) + (32 * (fixed_tm.tm_mon + 1)) + (512 * fixed_tm.tm_year)) << 16) |
-        ((fixed_tm.tm_sec / 2) + (32 * fixed_tm.tm_min) + (2048 * (uint32_t)fixed_tm.tm_hour));
-}
+    int month = ld.month() - 1;
+    int day = ld.day();
 
-unsigned long qDateToDosDate(QDateTime time)
-{
-    time_t rawtime = time.toTime_t();
-    struct tm * timeinfo;
+    if ( year < 0 || year > 207 || month < 1 || month > 31 )
+        return 0;
 
-    timeinfo = localtime(&rawtime);
-    timeinfo->tm_year = time.date().year() - 1900;
-    timeinfo->tm_mon = time.date().month() - 1;
-    timeinfo->tm_mday = time.date().day();
+    QTime lt = time.toLocalTime().time();
 
-    mktime(timeinfo);
+    unsigned int dosDate = static_cast<unsigned int>((day + (32 * (month + 1)) + (512 * year)));
+    unsigned int dosTime = static_cast<unsigned int>((lt.second() / 2) + (32 * lt.minute()) + (2048 * lt.hour()));
 
-    return tm_to_dosdate(timeinfo);
+    return dosDate << 16 | dosTime;
 }
 
 void WireSharkZipHelper::addFileToZip(zipFile zf, QString filepath, QString fileInZip)