http: reject excessive headers

HTTP::Parser::XS::PP does not reject excessively large
headers like the XS version.  Ensure we reject headers
over 16K since public-inbox should never need such large
request headers.

2 files changed, 17 insertions, 1 deletions

diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index 6c4c20d7..8988e7d2 100644
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -70,7 +70,11 @@ sub rbuf_process {
 
         # We do not support Trailers in chunked requests, for now
         # (they are rarely-used and git (as of 2.7.2) does not use them)
-        return quit($self, 400) if $r == -1 || $env{HTTP_TRAILER};
+        if ($r == -1 || $env{HTTP_TRAILER} ||
+                        # this length-check is necessary for PURE_PERL=1:
+                        ($r == -2 && length($self->{rbuf}) > 0x4000)) {
+                return quit($self, 400);
+        }
         return $self->watch_read(1) if $r < 0; # incomplete
         $self->{rbuf} = substr($self->{rbuf}, $r);
 
diff --git a/t/httpd-corner.t b/t/httpd-corner.t
index 833eb429..8670846c 100644
--- a/t/httpd-corner.t
+++ b/t/httpd-corner.t
@@ -84,6 +84,18 @@ my $spawn_httpd = sub {
         is($body, "hello world\n", 'callback body matches expected');
 }
 
+{
+        my $conn = conn_for($sock, 'excessive header');
+        $SIG{PIPE} = 'IGNORE';
+        $conn->write("GET /callback HTTP/1.0\r\n");
+        foreach my $i (1..500000) {
+                last unless $conn->write("X-xxxxxJunk-$i: omg\r\n");
+        }
+        ok(!$conn->write("\r\n"), 'broken request');
+        ok($conn->read(my $buf, 8192), 'read response');
+        my ($head, $body) = split(/\r\n\r\n/, $buf);
+        like($head, qr/\b400\b/, 'got 400 response');
+}
 
 # Unix domain sockets
 {