Need help with an irule to drop the request if pattern is not matched. The link and pattern is always as below whereby only the values will change....such as vid, height, quality values etc http://myserver.com/getimage.aspx?vid=84687usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=90&type=jpg&width=&height=&id=470746 http://myserver.com/getimage.aspx?vid=8461&usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=100&type=jpg&width=&height=&id=470784

Tested this with tclsh through the CLI with success. You could use the tcl string match command to build your filter Good A: Proper pattern set goodA "/getimage.aspx?vid=84687usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=90&type=jpg&width=&height=&id=470746" Bad A: Removed vid parameter set badA "/getimage.aspx?usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=90&type=jpg&width=&height=&id=470746" Good B: Proper pattern set goodB "/getimage.aspx?vid=8461&usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=100&type=jpg&width=&height=&id=470784" Bad B: Swapped parameter location (usehttp & vid) set badB "/getimage.aspx?usehttp=0&vid=8461&cat=default&class=books&size=custom&resize=1&dpi=300&quality=100&type=jpg&width=&height=&id=470784" Match pattern set pattern "/getimage.aspx\?vid=*usehttp=?&cat=*&class=*&size=*&resize=?&dpi=*&quality=*&type=*&width=*&height=*&id=*" echo "A (Good): [string match $pattern $goodA]" echo "A (Bad) : [string match $pattern $badA]" echo "B (Good): [string match $pattern $goodB]" echo "B (Bad) : [string match $pattern $badB]" so an iRule might look like this when HTTP_REQUEST { You don't have to set the pattern to a variable. you could just as easily paste it in the string match command, but this is a little clean (though not as performant) set pattern "/getimage.aspx\?vid=*usehttp=?&cat=*&class=*&size=*&resize=?&dpi=*&quality=*&type=*&width=*&height=*&id=*" if { not ([string match $pattern [string tolower [HTTP::uri]]]) } { Drop the request drop } }

Thanks Michael - initial testing here looks good

Michael Can you help again, I now need to have 2 different patterns and if not match on any of them then drop. I set pattern1 and pattern2 but Seem to be getting the if statement wrong as get a syntax error, or do I now need to use -glob

You may be better off using a switch statement for multiple patterns. something like this when HTTP_REQUEST { switch -glob -- [string tolower [HTTP::uri]] { "/getimage.aspx\?vid=*usehttp=?&cat=*&class=*&size=*&resize=?&dpi=*&quality=*&type=*&width=*&height=*&id=*" - "Insert another pattern here" { Looks good. Do nothing } default { Drop the request drop } }

when HTTP_REQUEST { set pattern1 "/getimage.aspx?vid=&usehttp=&cat=&class=&size=&resize=&dpi=&quality=&type=&width=&height=&id=" set pattern2 "/getimage.aspx?vid=&usehttp=&cat=&shade=&background=&colour=" if { not ([string match "$pattern1" or "$pattern2" [string tolower [HTTP::uri]]]) } { HTTP::respond 400 } } it does not like the OR

Forum Discussion

mikey_webb

Cirrus

Jan 07, 2015

Help with pattern match irule required

Need help with an irule to drop the request if pattern is not matched. The link and pattern is always as below whereby only the values will change....such as vid, height, quality values etc

http://myserver.com/getimage.aspx?vid=84687usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=90&type=jpg&width=&height=&id=470746

http://myserver.com/getimage.aspx?vid=8461&usehttp=0&cat=default&class=books&size=custom&resize=1&dpi=300&quality=100&type=jpg&width=&height=&id=470784

12 Replies

mikey_webb
Cirrus
Jan 22, 2015
Internal IP logs correctly and works External IP and pattern match logs correctly and works External IP and non-pattern match logs correctly but does not return the bad request page
mikey_webb
Cirrus
Jan 22, 2015
Return a blank page but works better and displays if I add content " 400 Bad request " I never had this issue prior to adding ip match as it use to return a 400 bad request in the tab