From 00e4b59bfb878fb35bcd78d18a51a827689ae6a5 Mon Sep 17 00:00:00 2001
From: wiire <wi7ire@gmail.com>
Date: Mon, 4 Jan 2016 10:05:16 +0100
Subject: [PATCH] Fixed time conversion issue due to different timezones and
 DST

Now UTC is used.
---
 src/pixiewps.c | 37 +++++++++++++++++------------------
 src/utils.h    | 52 +++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 61 insertions(+), 28 deletions(-)

diff --git a/src/pixiewps.c b/src/pixiewps.c
index d3463d5..c1070a4 100644
--- a/src/pixiewps.c
+++ b/src/pixiewps.c
@@ -79,7 +79,7 @@ memory_err:
 		return MEM_ERROR;
 	}
 
-	time_t start_p = 0, end_p = 0;
+	time_t start_p = (time_t) -1, end_p = (time_t) -1;
 	clock_t c_start = 0, c_end;
 
 	int opt = 0;
@@ -185,9 +185,10 @@ memory_err:
 					struct tm ts;
 					char buffer[30];
 					r_time = t_current.tv_sec;
-					ts = *localtime(&r_time);
+					ts = *gmtime(&r_time);
 					strftime(buffer, 30, "%c", &ts);
-					fprintf(stderr, "\n Pixiewps %s\n\n [*] System time: %s\n\n", LONG_VERSION, buffer);
+					fprintf(stderr, "\n Pixiewps %s\n\n [*] System time: %lu (%s UTC)\n\n",
+						LONG_VERSION, (unsigned long) t_current.tv_sec, buffer);
 					free(wps->error);
 					free(wps);
 					return ARG_ERROR;
@@ -290,11 +291,9 @@ usage_err:
 	}
 
 	/* Cannot specify --start or --end if --force is selected */
-	if (wps->bruteforce && (start_p || end_p)) {
-		if (start_p || end_p) {
-			snprintf(wps->error, 256, "\n [!] Cannot specify --start or --end if --force is selected!\n\n");
-			goto usage_err;
-		}
+	if (wps->bruteforce && ((start_p != (time_t) -1) || (end_p != (time_t) -1))) {
+		snprintf(wps->error, 256, "\n [!] Cannot specify --start or --end if --force is selected!\n\n");
+		goto usage_err;
 	}
 
 	if (wps->mode_auto) { /* Mode auto */
@@ -337,8 +336,8 @@ usage_err:
 		wps->end = t_now.tv_sec - MODE3_DAYS * SEC_PER_DAY;
 
 		/* Attributes --start and --end can be switched start > end or end > start */
-		if (start_p) {
-			if (end_p) {
+		if (start_p != (time_t) -1) {
+			if (end_p != (time_t) -1) {
 
 				/* Attributes --start and --end must be different */
 				if (start_p == end_p) {
@@ -361,7 +360,7 @@ usage_err:
 				}
 			}
 		} else {
-			if (end_p) {
+			if (end_p != (time_t) -1) {
 				if (end_p >= wps->start) {
 					snprintf(wps->error, 256, "\n [!] Bad Ending point!\n\n");
 					goto usage_err;
@@ -589,14 +588,14 @@ usage_err:
 						{
 							struct tm ts;
 							char buffer[30];
-							ts = *localtime(&wps->start);
+							ts = *gmtime(&wps->start);
 							strftime(buffer, 30, "%c", &ts);
-							printf("\n [DEBUG] %s:%d:%s(): Start: %10ld (%s)",
-								__FILE__, __LINE__, __func__, (long) wps->start, buffer);
-							ts = *localtime(&wps->end);
+							printf("\n [DEBUG] %s:%d:%s(): Start: %10lu (%s UTC)",
+								__FILE__, __LINE__, __func__, (unsigned long) wps->start, buffer);
+							ts = *gmtime(&wps->end);
 							strftime(buffer, 30, "%c", &ts);
-							printf("\n [DEBUG] %s:%d:%s(): End:   %10ld (%s)",
-								__FILE__, __LINE__, __func__, (long) wps->end, buffer);
+							printf("\n [DEBUG] %s:%d:%s(): End:   %10lu (%s UTC)",
+								__FILE__, __LINE__, __func__, (unsigned long) wps->end, buffer);
 							fflush(stdout);
 						}
 						#endif
@@ -812,9 +811,9 @@ usage_err:
 					char buffer[30];
 
 					seed_time = print_seed;
-					ts = *localtime(&seed_time);
+					ts = *gmtime(&seed_time);
 					strftime(buffer, 30, "%c", &ts);
-					printf(" (%s)", buffer);
+					printf(" (%s UTC)", buffer);
 				}
 			}
 		}
diff --git a/src/utils.h b/src/utils.h
index 0bff934..175e853 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -74,11 +74,43 @@ int get_int(char *in, int *out) {
 	return 0;
 };
 
+/* Custom timegm function made by Eric S Raymond */
+time_t c_timegm(register struct tm *t) {
+	register long year;
+	register time_t result;
+
+	#define MONTHS_PER_YEAR 12 /* Months per calendar year */
+
+	static const int cumdays[MONTHS_PER_YEAR] =
+		{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+
+	year = 1900 + t->tm_year + t->tm_mon / MONTHS_PER_YEAR;
+	result = (year - 1970) * 365 + cumdays[t->tm_mon % MONTHS_PER_YEAR];
+	result += (year - 1968) / 4;
+	result -= (year - 1900) / 100;
+	result += (year - 1600) / 400;
+	if ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0) &&
+		(t->tm_mon % MONTHS_PER_YEAR) < 2) {
+		result--;
+	}
+	result += t->tm_mday - 1;
+	result *= 24;
+	result += t->tm_hour;
+	result *= 60;
+	result += t->tm_min;
+	result *= 60;
+	result += t->tm_sec;
+	if (t->tm_isdst == 1)
+		result -= 3600;
+
+	return result;
+}
+
 /* Converts a [mm/]yyyy string to Unix date time */
 unsigned int get_unix_datetime(char *s, time_t *datetime) {
 	unsigned int len = strlen(s);
 	int month = 0, year;
-	struct tm tm;
+	struct tm t;
 
 	if (len == 4) {
 		if (get_int(s, &year))
@@ -106,18 +138,20 @@ unsigned int get_unix_datetime(char *s, time_t *datetime) {
 
 		if (get_int(s_month, &month) || get_int(s_year, &year))
 			return 1;
+		if ((year < 1970 && year > 2037) || (month < 1 && month > 12))
+			return 1;
 	} else {
 		return 1;
 	}
 
-	tm.tm_sec = 0;
-	tm.tm_min = 0;
-	tm.tm_hour = 0;
-	tm.tm_mday = 1;
-	tm.tm_mon = month - 1;
-	tm.tm_year = year - 1900;
-	tm.tm_isdst = -1;
-	*datetime = mktime(&tm);
+	t.tm_sec = 0;
+	t.tm_min = 0;
+	t.tm_hour = 0;
+	t.tm_mday = 1;
+	t.tm_mon = month - 1;
+	t.tm_year = year - 1900;
+	t.tm_isdst = 0;
+	*datetime = c_timegm(&t);
 
 	if (*datetime < 0)
 		return 1;