Pcre_exec() failed: -10

Hello,

I’ve a rule below in nginx config to 404 if the argument of search query
is
a non printable ascii character. Nginx is compiled with pcre and pcre
seem** (refer 4.d below) to have utf8 support and unicode support
enabled
but nginx fails with “pcre_exec() failed: -10” error when it encounters
the
regex.

Any pointers, please? Please refer below for more details.

TIA,

Krishna!

1. from nginx config

if ($args ~ “(UTF8)^.[^\x21-\x7E].*$”) {

     return 404;

 }

2. from access log:

54.169.206.188 [26/Jan/2016:20:29:10
/search?userQuery=Taurm\xE9+Taurme+Corporate+Casual+Slip+On+Shoe+()

3. from error log:

2016/01/26 20:29:10 [alert] 27700#0: 43933484 on
“userQuery=Taurm+Taurme+Corporate+Casual+Slip+On+Shoe+()” using
"(UTF8)^.[^\x00-\x7F].
$", client: 54.169.206.188, server:
search.paytm.com, request: “GET
/search?userQuery=Taurm+Taurme+Corporate+Casual+Slip+On+Shoe+()
HTTP/1.1”,
host: “search.paytm.com

*4. nginx and pcre *

a) nginx -V

nginx version: openresty/1.7.2.1

b) ldd /usr/sbin/nginx|grep pcre

    lib*pcre*.so.3 => /lib/x86_64-linux-gnu/lib*pcre*.so.3

(0x00007fbdb64a7000)
c) dpkg -l|grep pcre

ii libpcre3:amd64 1:8.31-2ubuntu2.1
amd64
Perl 5 Compatible Regular Expression Library - runtime files

**d) Since ubuntu no longer ships with pcretest, there was no easy way
to
see if utf8 support is enabled but from ubuntu package build logs for
our
version, I can see that is how it is built. Also, can confirm the same
from
config.log when building the debian package locally on my machine:

https://launchpadlibrarian.net/212590020/buildlog_ubuntu-trusty-amd64.pcre3_1%3A8.31-2ubuntu2.1_BUILDING.txt.gz

Hello!

On Tue, Jan 26, 2016 at 10:03:16PM +0530, Krishna PMV wrote:

TIA,

2016/01/26 20:29:10 [alert] 27700#0: 43933484 on
“userQuery=Taurm+Taurme+Corporate+Casual+Slip+On+Shoe+()” using
"(UTF8)^.[^\x00-\x7F].
$", client: 54.169.206.188, server:
search.paytm.com, request: “GET
/search?userQuery=Taurm+Taurme+Corporate+Casual+Slip+On+Shoe+() HTTP/1.1”,
host: “search.paytm.com

The error is returned by PCRE due to an invalid UTF-8 string being
checked as UTF-8 one. Note “\xE9” in the access log entry. Some
additional information can be found in the pcreunicode manpage.


Maxim D.
http://nginx.org/

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