* time.c (time_overflow_p): Avoid signed integer overflow.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42445 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 14 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 2eee3cd6af..0e2b49d9c4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Aug  8 21:10:05 2013  Tanaka Akira  <akr@fsij.org>
+
+	* time.c (time_overflow_p): Avoid signed integer overflow.
+
 Thu Aug  8 19:58:02 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* thread.c (rb_threadptr_pending_interrupt_check_mask):
diff --git a/time.c b/time.c
index 211fcead07..de914e36e3 100644
--- a/time.c
+++ b/time.c
@@ -2217,24 +2217,25 @@ time_init(int argc, VALUE *argv, VALUE time)
 static void
 time_overflow_p(time_t *secp, long *nsecp)
 {
-    time_t tmp, sec = *secp;
+    time_t sec = *secp;
     long nsec = *nsecp;
+    long sec2;
 
     if (nsec >= 1000000000) {	/* nsec positive overflow */
-	tmp = sec + nsec / 1000000000;
-	nsec %= 1000000000;
-	if (sec > 0 && tmp < 0) {
+        sec2 = nsec / 1000000000;
+	if (TIMET_MAX - sec2 < sec) {
 	    rb_raise(rb_eRangeError, "out of Time range");
 	}
-	sec = tmp;
+	nsec %= 1000000000;
+	sec += sec2;
     }
     if (nsec < 0) {		/* nsec negative overflow */
-	tmp = sec + NDIV(nsec,1000000000); /* negative div */
-	nsec = NMOD(nsec,1000000000);      /* negative mod */
-	if (sec < 0 && tmp > 0) {
+	sec2 = NDIV(nsec,1000000000); /* negative div */
+	if (sec < TIMET_MAX - sec2) {
 	    rb_raise(rb_eRangeError, "out of Time range");
 	}
-	sec = tmp;
+	nsec = NMOD(nsec,1000000000);      /* negative mod */
+	sec = sec + sec2;
     }
 #ifndef NEGATIVE_TIME_T
     if (sec < 0)