date: detect underflow/overflow when parsing dates with timezone offset

Overriding the date of a commit to be close to "1970-01-01 00:00:00"
with a large enough positive timezone for the equivelant GMT time to be
before the epoch is considered valid by `parse_date_basic`. Similar
behaviour occurs when using a date close to "2099-12-31 23:59:59" (the
maximum date allowed by `tm_to_time_t`) with a large enough negative
timezone offset.

This leads to an integer underflow or underflow respectively in the
commit timestamp, which is not caught by `git-commit`, but will cause
other services to fail, such as `git-fsck`, which, for the first case,
reports "badDateOverflow: invalid author/committer line - date causes
integer overflow".

Instead check the timezone offset and fail if the resulting time comes
before the epoch "1970-01-01T00:00:00Z" or after the maximum date
"2099-12-31T23:59:59Z".

Using the REQUIRE_64BIT_TIME prerequisite, make sure that the tests
near the end of Git time (aka end of year 2099) are not attempted on
purely 32-bit systems, as they cannot express timestamp beyond 2038
anyway.

Signed-off-by: Darcy Burke <acednes@gmail.com>
[jc: fixups for 32-bit platforms]
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/t/t0006-date.sh b/t/t0006-date.sh
index 24e8647f26..fd373e1b39 100755
--- a/t/t0006-date.sh
+++ b/t/t0006-date.sh
@@ -123,6 +123,39 @@ check_parse '2008-02-14 20:30:45 -05:00' '2008-02-14 20:30:45 -0500'
 check_parse '2008-02-14 20:30:45' '2008-02-14 20:30:45 -0500' EST5
 check_parse 'Thu, 7 Apr 2005 15:14:13 -0700' '2005-04-07 15:14:13 -0700'
 
+check_parse '1970-01-01 00:00:00' '1970-01-01 00:00:00 +0000'
+check_parse '1970-01-01 00:00:00 +00' '1970-01-01 00:00:00 +0000'
+check_parse '1970-01-01 00:00:00 Z' '1970-01-01 00:00:00 +0000'
+check_parse '1970-01-01 00:00:00 -01' '1970-01-01 00:00:00 -0100'
+check_parse '1970-01-01 00:00:00 +01' bad
+check_parse '1970-01-01 00:00:00 +11' bad
+check_parse '1970-01-01 00:59:59 +01' bad
+check_parse '1970-01-01 01:00:00 +01' '1970-01-01 01:00:00 +0100'
+check_parse '1970-01-01 01:00:00 +11' bad
+check_parse '1970-01-02 00:00:00 +11' '1970-01-02 00:00:00 +1100'
+check_parse '1969-12-31 23:59:59' bad
+check_parse '1969-12-31 23:59:59 +00' bad
+check_parse '1969-12-31 23:59:59 Z' bad
+check_parse '1969-12-31 23:59:59 +11' bad
+check_parse '1969-12-31 23:59:59 -11' bad
+
+REQUIRE_64BIT_TIME=HAVE_64BIT_TIME
+check_parse '2099-12-31 23:59:59' '2099-12-31 23:59:59 +0000'
+check_parse '2099-12-31 23:59:59 +00' '2099-12-31 23:59:59 +0000'
+check_parse '2099-12-31 23:59:59 Z' '2099-12-31 23:59:59 +0000'
+check_parse '2099-12-31 23:59:59 +01' '2099-12-31 23:59:59 +0100'
+check_parse '2099-12-31 23:59:59 -01' bad
+check_parse '2099-12-31 23:59:59 -11' bad
+check_parse '2099-12-31 23:00:00 -01' bad
+check_parse '2099-12-31 22:59:59 -01' '2099-12-31 22:59:59 -0100'
+check_parse '2100-00-00 00:00:00' bad
+check_parse '2099-12-30 00:00:00 -11' '2099-12-30 00:00:00 -1100'
+check_parse '2100-00-00 00:00:00 +00' bad
+check_parse '2100-00-00 00:00:00 Z' bad
+check_parse '2100-00-00 00:00:00 -11' bad
+check_parse '2100-00-00 00:00:00 +11' bad
+REQUIRE_64BIT_TIME=
+
 check_approxidate() {
 	echo "$1 -> $2 +0000" >expect
 	test_expect_${3:-success} "parse approxidate ($1)" "