Bug #77193 [Opn->Asn]: Infinite loop in preg_replace_callback

Edit report at https://bugs.php.net/bug.php?id=77193&edit=1 ID: 77193 Updated by: cmb@php.net Reported by: mlocati at gmail dot com Summary: Infinite loop in preg_replace_callback -Status: Open +Status: Assigned Type: Bug Package: PCRE related PHP Version: 7.3.0RC6 -Assigned To: +Assigned To: ab Block user comment: N Private report: N New Comment: Thanks for testing, Michele! Then we should go with Anatol's patch. Not sure if it should go into PHP-7.3.0. Previous Comments: ------------------------------------------------------------------------ [2018-11-29 13:39:06] mlocati at gmail dot com Just for the records, I'm compiling a 32-bit PHP under Windows with configure --disable-all --with-all-shared --enable-cli --enable-phar --enable-json --enable-filter --with-iconv --enable-pdo --with-mysqli --with-mysqlnd --with-pdo-mysql --with-openssl --with-simplexml --with-libxml --with-gd --enable-mbstring --enable-tokenizer --with-dom --with-xml --enable-xmlreader --enable-xmlwriter --enable-hash --enable-fileinfo --enable-session --enable-zip nmake ------------------------------------------------------------------------ [2018-11-29 13:33:56] mlocati at gmail dot com @cmb I just tried your patch instead of the @ab one, but with it we still have the infinite loop... ------------------------------------------------------------------------ [2018-11-29 11:34:17] cmb@php.net I wonder whether we don't have to call pcre2_get_mark() before calling pcre2_get_ovector_pointer(), i.e. partly reverting commit b81d712. I mean something like this instead the patch above: ext/pcre/php_pcre.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/ext/pcre/php_pcre.c b/ext/pcre/php_pcre.c index 5165209b85..4277ffb6aa 100644 --- a/ext/pcre/php_pcre.c +++ b/ext/pcre/php_pcre.c @@ -1792,6 +1792,7 @@ static zend_string *php_pcre_replace_func_impl(pcre_cache_entry *pce, zend_strin char *match, /* The current match */ *piece; /* The current piece of subject */ size_t result_len; /* Length of result */ + PCRE2_SPTR mark = NULL; /* Target for MARK name */ zend_string *result; /* Result of replacement */ zend_string *eval_result; /* Result of custom function */ pcre2_match_data *match_data; @@ -1852,6 +1853,8 @@ static zend_string *php_pcre_replace_func_impl(pcre_cache_entry *pce, zend_strin while (1) { piece = subject + start_offset; + mark = pcre2_get_mark(match_data); + if (count >= 0 && limit) { /* Check for too many substrings condition. */ if (UNEXPECTED(count == 0)) { @@ -1881,8 +1884,7 @@ matched: new_len = result_len + offsets[0] - start_offset; /* part before the match */ /* Use custom function to get replacement string and its length. */ - eval_result = preg_do_repl_func(fci, fcc, subject, offsets, subpat_names, count, - pcre2_get_mark(match_data)); + eval_result = preg_do_repl_func(fci, fcc, subject, offsets, subpat_names, count, mark); ZEND_ASSERT(eval_result); new_len = zend_safe_address_guarded(1, ZSTR_LEN(eval_result), new_len); [1] <http://git.php.net/?p=php-src.git;a=commit;h=b81d712961aa3cbc64dc8bb521f2427cf443e550> ------------------------------------------------------------------------ [2018-11-29 09:04:48] mlocati at gmail dot com @ab Yes! That patch fixed the issue: C:\MyPath>composer test -- --filter=ContentPageTranslateTest::testFrom > phpunit "--filter=ContentPageTranslateTest::testFrom" PHPUnit 4.8.36 by Sebastian Bergmann and contributors. Runtime: PHP 7.3.0-dev Configuration: C:\MyPath\phpunit.xml . Time: 4.68 seconds, Memory: 30.00MB OK (1 test, 1 assertion) Great job, Anatol! ------------------------------------------------------------------------ [2018-11-28 20:32:20] ab@php.net @mlocati thanks, with the docker way reproduced it as well. I still can't repro it on a reduced snippet. I guess, the method call inside the callback somehow resets the match context (so somewhere in the call trace is a PCRE API call), thus preventing loop termination. Could you please check, whether this fixes it? diff --git a/ext/pcre/php_pcre.c b/ext/pcre/php_pcre.c index 5165209b85..f8fc721d81 100644 --- a/ext/pcre/php_pcre.c +++ b/ext/pcre/php_pcre.c @@ -1880,6 +1880,9 @@ matched: new_len = result_len + offsets[0] - start_offset; /* part before the match */ + /* Advance to the next piece. */ + start_offset = offsets[1]; + /* Use custom function to get replacement string and its length. */ eval_result = preg_do_repl_func(fci, fcc, subject, offsets, subpat_names, count, pcre2_get_mark(match_data)); @@ -1908,9 +1911,6 @@ matched: limit--; - /* Advance to the next piece. */ - start_offset = offsets[1]; - /* If we have matched an empty string, mimic what Perl's /g options does. This turns out to be rather cunning. First we set PCRE2_NOTEMPTY_ATSTART and try the match again at the same point. If this fails (picked up above) we ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=77193 -- Edit this bug report at https://bugs.php.net/bug.php?id=77193&edit=1