From: Jeff King Date: Wed, 18 Jun 2014 19:51:17 GMT Subject: [PATCH 12/16] stat_opt: check extra strlen call Message-ID: <20140618195117.GL22622@sigill.intra.peff.net> In-Reply-To: <20140618194117.GA22269@sigill.intra.peff.net> As in earlier commits, the diff option parser uses starts_with to find that an argument starts with "--stat-", and then adds strlen("stat-") to find the rest of the option. However, in this case the starts_with and the strlen are separated across functions, making it easy to call the latter without the former. Let's use skip_prefix instead of raw pointer arithmetic to catch such a case. Signed-off-by: Jeff King --- Another possibility would be for stat_opt to take only the prefix-skipped part of the string. But that would involve refactoring its use of "av" (it needs the whole array because it may need to grab a follow-on argument). diff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/diff.c b/diff.c index 2378ae4..06bdfb8 100644 --- a/diff.c +++ b/diff.c @@ -3422,7 +3422,8 @@ static int stat_opt(struct diff_options *options, const char **av) int count = options->stat_count; int argcount = 1; - arg += strlen("--stat"); + if (!skip_prefix(arg, "--stat", &arg)) + die("BUG: stat option does not begin with --stat: %s", arg); end = (char *)arg; switch (*arg) { -- 2.0.0.566.gfe3e6b2