rhel 6 - apache httpd - php5.3.3

Also got this error -

preg_match(): Compilation failed: range out of order in character class at offset 11 [popup_httpstep.php:55 → check_fields() → check_field() → calc_exp() → calc_exp2() → eval() → preg_match() in /wawa_mnt1/apache_httpd/httpd-2.2.31/htdocs/zabbix/include/validate.inc.php(105) : eval()'d code:1]
Incorrect value "Zabbix Homepage" for "Name" field.

It seems to complain about the following regular expression:

preg_grep('/([^\x{00}-\x{1F}]+?)?/i', $stepNames)

Have you installed Zabbix for the first time? Has it ever worked in prior versions? Have you upgraded Web server or PHP packages recently?

While we still need to figure out your original problem, there is something to be fixed anyway.

In particular, there is the following code in CHttpTest.php:

$stepNames = zbx_objectValues($httpTest['steps'], 'name');
if (!empty($stepNames) && !preg_grep('/'.ZBX_PREG_PARAMS.'/i', $stepNames)) {
	self::exception(ZBX_API_ERROR_PARAMETERS, _('Web scenario step name should contain only printable characters.'));
}

This is true - Web scenario step name should only contain printable characters. However, it verifies the name using the regular expression in the previous comment, but not all ASCII characters from 0 to 127 are printable! Also, why ^ symbol is needed there?

That regular expression is defined in the following way:

define('ZBX_PREG_PRINT', '^\x{00}-\x{1F}');

Apparently, this is a misnomer.

iivs The ^ means not in the range. The particular example doesn't say that, but we have to look at it this way

[^\x{00}-\x{1F}]

. But the problem might with curly braces. They are optional since there are only two hexadecimal digits. Not sure whether it's a bug in PCRE library or what, because

[^\x{00}-\x{1F}]

and

[^\x00-\x1F]

are both correct syntaxes. I think the curly braces are used only because we use eval() function in frontend while checking through check_fields() all that complex chain of other functions. If we remove them, we need to change
this

return 'preg_match("/'.ZBX_PREG_PARAMS.'/",{'.$var.'})&&';

to this

return 'preg_match(\'/'.ZBX_PREG_PARAMS.'/\',{'.$var.'})&&';

in KEY_PARAM()
to work with eval() correctly. Otherwise there will be new problems. However, I understood that the validation for non-printable characters is not actually needed, since we allow anything inside item key. But if we remove the validation, we could then have problems with trigger expressions. There is another complex expression using ZBX_PREG_PRINT. So maybe removing validation is not a good option. And here's the catch. We can write the expression like this

/([^\x00-\x1F]+?)?/i

, but it somehow passes through the validation. I'm not quite sure why. But there is another function checkNames() that uses same expression. We could use the same regular expression for step names used in scenario names and it will look like this

/^([^\x00-\x1F])+$/u

Or maybe just add ^ and $? It could look like this

^([^\x00-\x1F]+?)?${noformat} Any thoughts on this matter? I'm still puzzled by this.

iivs In the end we have decided to remove the non-printable character restriction for scenario names and change the regular expression so that it doesn't use curly braces.

Hello Aleksandrs,

Quick update on this - the main error I receive repedtly now is the following - I have been unable to reproduce the initial error that I posted with this bug.

preg_match(): Compilation failed: range out of order in character class at offset 11 [popup_httpstep.php:55 → check_fields() → check_field() → calc_exp() → calc_exp2() → eval() → preg_match() in /wawa_mnt1/apache_httpd/httpd-2.2.31/htdocs/zabbix/include/validate.inc.php(105) : eval()'d code:1]
Incorrect value "Zabbix Homepage" for "Name" field.

To answer your questions - This is a brand new install of Zabbix installed from source - 2.4.7. I have never been able to get this work and also have not upgraded or changed apache or php.
Thanks!

Hello, Brian!

I'm just curious what is the version of PCRE library? I doubt that the problem is due to old version, but still would be interesting to know since I could only reproduce the error with that regular expression on PHP 5.0.4 and PHP 5.0.5. And the PCRE library for those PHP versions is very, very old (4.5 01-December-2003). Also I'm, 99.99% positive that the same error might be also in tr_logform.php, because it uses same regular expression there. I cannot check if that's true, since Zabbix requires PHP >= 5.1.6 (for v2.0).

Ivo,

Here you go -

PCRE version 7.8 2008-09-05
Compiled with
UTF-8 support
Unicode properties support
Newline sequence is LF
\R matches all Unicode newlines
Internal link size = 2
POSIX malloc threshold = 10
Default match limit = 10000000
Default recursion depth limit = 10000000
Match recursion uses stack

(1) Removed translation strings:

• Scenario step name should contain only printable characters.

gunarspujats CLOSED

RESOLVED in svn://svn.zabbix.com/branches/dev/ZBX-10316

Successfully tested!

Fixed in:

• pre-2.0.17rc1 r59024
• pre-2.2.12rc1 r59026
• pre-3.0.2rc1 r59027
• pre-3.1.0 (trunk) r59028

(2) API changelogs: 2.0, 2.2 and 3.0 updated. Please, review.

sasha CLOSED