From: Eric Wong (Contractor, The Linux Foundation) <e@80x24.org>
Date: Tue, 27 Mar 2018 20:09:06 +0000 (+0000)
Subject: http: fix modification of read-only value
X-Git-Tag: v1.1.0-pre1~118
X-Git-Url: http://www.git.stargrave.org/?p=public-inbox.git;a=commitdiff_plain;h=cc615e445899ad719b7b84babae0cf7907b2a3e3

http: fix modification of read-only value

This fails in the rare case we get a partial send() on "\r\n"
when writing chunked HTTP responses out.
---

diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index 3dd49be3..bc10814e 100644
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -316,9 +316,12 @@ sub more ($$) {
 	if (MSG_MORE && !$self->{write_buf_size}) {
 		my $n = send($self->{sock}, $_[1], MSG_MORE);
 		if (defined $n) {
-			my $dlen = length($_[1]);
-			return 1 if $n == $dlen; # all done!
-			$_[1] = substr($_[1], $n, $dlen - $n);
+			my $nlen = length($_[1]) - $n;
+			return 1 if $nlen == 0; # all done!
+			eval { $_[1] = substr($_[1], $n, $nlen) };
+			if ($@) { # modification of read-only value:
+				return $self->write(substr($_[1], $n, $nlen));
+			}
 			# fall through to normal write:
 		}
 	}