ext/pcre: fix mdata_used race conditions in PCRE functions #21291
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,58 @@ | ||
| --TEST-- | ||
| PCRE re-entrancy: nested calls should not corrupt global match data | ||
| --EXTENSIONS-- | ||
| pcre | ||
| --FILE-- | ||
| <?php | ||
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| echo "Testing nested PCRE calls..." . PHP_EOL; | ||
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| $subject = 'abc'; | ||
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| // preg_replace_callback is the most common way to trigger re-entrancy | ||
| $result = preg_replace_callback('/./', function($m) { | ||
| $char = $m[0]; | ||
| echo "Outer match: $char" . PHP_EOL; | ||
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| // 1. Nested preg_match | ||
| preg_match('/./', 'inner', $inner_m); | ||
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| // 2. Nested preg_replace (string version) | ||
| preg_replace('/n/', 'N', 'inner'); | ||
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| // 3. Nested preg_split | ||
| preg_split('/n/', 'inner'); | ||
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| // 4. Nested preg_grep | ||
| preg_grep('/n/', ['inner']); | ||
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| // If any of the above stole the global mdata buffer without setting mdata_used, | ||
| // the 'offsets' used by this outer preg_replace_callback loop would be corrupted. | ||
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| return strtoupper($char); | ||
| }, $subject); | ||
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| var_dump($result); | ||
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| echo PHP_EOL . "Testing deep nesting..." . PHP_EOL; | ||
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| $result = preg_replace_callback('/a/', function($m) { | ||
| return preg_replace_callback('/b/', function($m) { | ||
| return preg_replace_callback('/c/', function($m) { | ||
| return "SUCCESS"; | ||
| }, 'c'); | ||
| }, 'b'); | ||
| }, 'a'); | ||
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| var_dump($result); | ||
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| ?> | ||
| --EXPECT-- | ||
| Testing nested PCRE calls... | ||
| Outer match: a | ||
| Outer match: b | ||
| Outer match: c | ||
| string(3) "ABC" | ||
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| Testing deep nesting... | ||
| string(7) "SUCCESS" |
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Please just use true for the assignments to mdata_used
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sure I was just trying to be "consistent" within stable branch :)
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I don't think that's necessary when talking about new code. As a follow-up you can make things consistent.