that passes my test and GCC's -Wstrict-overflow=5 no longer complains about those two lines (though it does still have several other complaints about localtime.c). committed to Android's C library as 713fe6463e6ff8cb9689aa8ead88c885d25d03aa (https://android-review.googlesource.com/#/c/64140/).

thanks!


On Thu, Aug 22, 2013 at 12:53 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
On 08/22/13 11:35, enh wrote:

> looking at the Android AOSP git history, it looks like we found and
> fixed this bug years ago but never talked to upstream about it:

Thanks for the heads-up.  If I understand all those patches aright,
the following patch (which I've pushed to the experimental github
repository) should fix things.  I've fixed some other integer-overflow
issues in the past few months, but I missed this one (and there are
probably others I've missed).

>From 943a6621866e9d6e654f5cfe1494378c1fb8957a Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 22 Aug 2013 12:47:51 -0700
Subject: [PATCH] * localtime.c: Fix another integer overflow bug in mktime.

(time2sub): Avoid undefined behavior on time_t overflow.
Reported by Elliott Hughes in
<http://mm.icann.org/pipermail/tz/2013-August/019580.html>.
---
 localtime.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/localtime.c b/localtime.c
index f58b20a..a0a4e5e 100644
--- a/localtime.c
+++ b/localtime.c
@@ -1789,14 +1789,14 @@ time2sub(struct tm *const tmp,
                } else  dir = tmcomp(&mytm, &yourtm);
                if (dir != 0) {
                        if (t == lo) {
-                               ++t;
-                               if (t <= lo)
+                               if (t == time_t_max)
                                        return WRONG;
+                               ++t;
                                ++lo;
                        } else if (t == hi) {
-                               --t;
-                               if (t >= hi)
+                               if (t == time_t_min)
                                        return WRONG;
+                               --t;
                                --hi;
                        }
                        if (lo > hi)
--
1.7.11.7





--
Elliott Hughes - http://who/enh - http://jessies.org/~enh/
Java i18n/JNI/NIO, or bionic questions? Mail me/drop by/add me as a reviewer.