From 98682c7a8792e7e79e487fea5024d25cee5aa310 Mon Sep 17 00:00:00 2001
From: nsfisis contained unnecessary whitespaces inside it
---
.../phperkaigi-2023-unused-token-quiz-2/index.html | 36 +++++++---------------
1 file changed, 11 insertions(+), 25 deletions(-)
(limited to 'public/posts/2022-11-19/phperkaigi-2023-unused-token-quiz-2')
diff --git a/public/posts/2022-11-19/phperkaigi-2023-unused-token-quiz-2/index.html b/public/posts/2022-11-19/phperkaigi-2023-unused-token-quiz-2/index.html
index 7aa97a9..808f1b4 100644
--- a/public/posts/2022-11-19/phperkaigi-2023-unused-token-quiz-2/index.html
+++ b/public/posts/2022-11-19/phperkaigi-2023-unused-token-quiz-2/index.html
@@ -72,8 +72,7 @@
注意: これはボツ問なので、得られたトークンを PHPerKaigi で入力してもポイントにはならない。
- <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
+ <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
@@ -82,8 +81,7 @@
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
- <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
-
+ <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
"And Then There Were None" (そして誰もいなくなった) と名付けた作品。変則 quine (自分自身と同じソースコードを出力するプログラム) になっている。 @@ -96,8 +94,7 @@ 実行してみると、次のような出力が得られる。
-
- #
+ #
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
@@ -106,15 +103,13 @@
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
- <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
-
+ <?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
1 行目を除き、先ほどのコードとほぼ同じものが出てきた。もう一度実行してみる。
-
- #
+ #
W
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
@@ -123,15 +118,13 @@ W
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
-<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
-
+<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s='<?php printf((isset($s)?fn($s)=>trim($s,""):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
今度は 2 行目が書き換えられた。すべての行が変化するまで繰り返すと次のようになる。
-
- #
+ #
W
E
L
@@ -140,8 +133,7 @@ V
E
P
H
-P
-
+P
トークン「#WELOVEPHP」が手に入った。 @@ -158,9 +150,7 @@ P Vim で開くと次のようになる (1 行目を抜粋)。
-
- <?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s='<200b><?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
-
+ <?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s='<200b><?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>')."\n","\x27$s\x27");?>
<200b>と表示されているのは、Unicode の U+200b で、ゼロ幅スペースである。
@@ -185,17 +175,13 @@ P
続いて、トークンへの変換ロジックを解析する。注目すべきはこの部分だ。以下、ゼロ幅スペースは Vim での表示に合わせて<200b>と記載する。
- fn($s)=>chr(strlen($s)/3)
-
+ fn($s)=>chr(strlen($s)/3)
PHP のstrlen()は文字列のバイト数を返す。1 行目の$sは以下の内容となっており、
- $s='<200b><?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>'
-
+ $s='<200b><?php printf((isset($s)?fn($s)=>trim($s,"<200b>"):fn($s)=>chr(strlen($s)/3))($s=%s)."\n","\x27$s\x27");?>'
このソースコードは UTF-8 で書かれているので、105 バイトになる。それを 3 で割ると 35 となり、これは#の ASCII コードと一致する。他の行も、同様にしてゼロ幅スペースを詰めることで文字列長を調整し、トークンをエンコードしている。
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cgit v1.2.3-70-g09d2