index: support --max-size / publicinbox.indexMaxSize

In normal mail paths, we can rely on MTAs being configured with
reasonable limits in the -watch and -mda mail injection paths.

However, the MTA is bypassed in a git-only delivery path, a BOFH
could inject a large message and DoS users attempting to mirror
a public-inbox.

This doesn't protect unindexed WWW interfaces from Email::MIME
memory explosions on v1 inboxes.  Probably nobody cares about
unindexed WWW interfaces anymore, especially now that Xapian is
optional for indexing.

1 files changed, 20 insertions, 0 deletions

diff --git a/t/admin.t b/t/admin.t
index a9d67d25..c25667b2 100644
--- a/t/admin.t
+++ b/t/admin.t
@@ -78,4 +78,24 @@ SKIP: {
 }
 
 chdir '/';
+
+my @pairs = (
+        '1g' => 1024 ** 3,
+        666 => 666,
+        '1500K' => 1500 * 1024,
+        '15m' => 15 * (1024 ** 2),
+);
+
+while (@pairs) {
+        my ($in, $out) = splice(@pairs, 0, 2);
+        my $orig = $in;
+        ok(PublicInbox::Admin::parse_unsigned(\$in), "parse_unsigned $orig");
+        is($in, $out, "got $orig => ($in == $out)");
+}
+
+for my $v ('', 'bogus', '1p', '1gig') {
+        ok(!PublicInbox::Admin::parse_unsigned(\$v),
+                "parse_unsigned rejects $v");
+}
+
 done_testing();