[PATCH 2/2] parse_date: fix signedness in timezone calculation
- From
Jeff King <peff@peff.net>
- Date
- Jul 4, 2010, 11:00 UTC
- Message-ID
- <20100704110017.GA23121@sigill.intra.peff.net>
- In-Reply-To
- <20100704104834.GA23070@sigill.intra.peff.net>
When no timezone is specified, we deduce the offset by subtracting the result of mktime from our calculated timestamp.
However, our timestamp is stored as an unsigned integer, meaning we perform the subtraction as unsigned. For a negative offset, this means we wrap to a very high number, and our numeric timezone is in the millions of hours. You can see this bug by doing:
$ TZ=EST \
GIT_AUTHOR_DATE='2010-06-01 10:00' \
git commit -a -m foo
$ git cat-file -p HEAD | grep author
author Jeff King <peff@peff.net> 1275404416 +119304128Instead, we should perform this subtraction as a time_t, the same type that mktime returns.
Signed-off-by: Jeff King <peff@peff.net> --- Are there any platforms with an unsigned time_t? In that case, we would need to use a regular "long" to get signedness. Presumably on such platforms "long" will grow with time_t to 64-bits so we don't create a Y2038 problem (though most of the rest of the code uses "unsigned long" interchangeably with time_t, so we have a Y2106 problem in that case anyway).
date.c | 2 +- t/t0006-date.sh | 1 + 2 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/date.c b/date.c index 68cdcaa..3c981f7 100644 --- a/date.c +++ b/date.c @@ -635,7 +635,7 @@ int parse_date_toffset(const char *date, unsigned long *timestamp, int *offset) /* mktime uses local timezone */ *timestamp = tm_to_time_t(&tm); if (*offset == -1) - *offset = (*timestamp - mktime(&tm)) / 60; + *offset = ((time_t)*timestamp - mktime(&tm)) / 60; if (*timestamp == -1) return -1; diff --git a/t/t0006-date.sh b/t/t0006-date.sh index 3ea4f9e..b2df4fe 100755 --- a/t/t0006-date.sh +++ b/t/t0006-date.sh @@ -39,6 +39,7 @@ check_parse 2008-02 bad check_parse 2008-02-14 bad check_parse '2008-02-14 20:30:45' '2008-02-14 20:30:45 +0000' check_parse '2008-02-14 20:30:45 -0500' '2008-02-14 20:30:45 -0500' +check_parse '2008-02-14 20:30:45' '2008-02-14 20:30:45 -0500' EST check_approxidate() { echo "$1 -> $2 +0000" >expect
-- 1.7.2.rc1.209.g2a36c