browser icon indicating copy to clipboard operation
browser copied to clipboard

Published 20 hours ago • verified publisher icon fnando

user_agent_size_limit of 2048 causes exceptions on some requests

Open tomash opened this issue 8 months ago • 0 comments

A real User-Agent header I've encountered in an appplication:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (Macintosh; Intel Mac OS X 14.7; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (X11; Linux i686; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0Mozilla/5.0 (Macintosh; Intel Mac OS X 14_7_1) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/605.1.15Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0)Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0)Mozilla/4.0 (compatible; MSIE 9.0; Windows NT 6.0; Trident/5.0)Mozilla/4.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)Mozilla/5.0 (Windows NT 6.1; Trident/7.0; rv:11.0) like GeckoMozilla/5.0 (Windows NT 6.2; Trident/7.0; rv:11.0) like GeckoMozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like GeckoMozilla/5.0 (Windows NT 10.0; Trident/7.0; rv:11.0) like GeckoMozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/130.0.2849.80Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/130.0.2849.80Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/114.0.0.0Mozilla/5.0 (Windows NT 10.0; WOW64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/114.0.0.0Mozilla/5.0 (Macintosh; Intel Mac OS X 14_7_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/114.0.0.0Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/114.0.0.0Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Vivaldi/7.0.3495.14Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Vivaldi/7.0.3495.14Mozilla/5.0 (Macintosh; Intel Mac OS X 14_7_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Vivaldi/7.0.3495.14Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Vivaldi/7.0.3495.14Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Vivaldi/7.0.3495.14Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 YaBrowser/24.10.1.669 Yowser/2.5 Safari/537.36Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 YaBrowser/24.10.1.669 Yowser/2.5 Safari/537.36

...is 3251 bytes in length, so causes exceptions when trying to Browser.new(user_agent_string).

I am aware that such user agent string is at least fishy and stupid, and I don't expect browser to accurately tell me which actual browser should I treat it as. But I'd like my application not broken in such cases.

Quick monkeypatch shows that increasing user_agent_size_limit in Browser module to 4096 does not break the gem and allows such behemoths to be processed.

tomash avatar Feb 04 '25 15:02 tomash