Nginx: deny requests based on certain conditions

Question

In Apache I have a bunch of rules to block certain unwanted requests.

# Block libwww-perl/5.805 from attempting to exploit security vulnerabilities  
RewriteCond %{HTTP_USER_AGENT} ^libwww\-perl/.+ [NC]     
RewriteCond %{QUERY_STRING} .
RewriteRule . - [F,L] 

# Block generic Java-based clients
RewriteCond %{HTTP_USER_AGENT} ^Java/1\.6\.0_04 [NC]
RewriteRule . - [F,L]

# Block generic Mozilla clients
RewriteCond %{HTTP_USER_AGENT} ^Mozilla/5\.0$ [NC]
RewriteRule . - [F,L]

What is the most efficient way to accomplish the same task in nginx?

Answer 1

# Block libwww-perl/5.805 from attempting to exploit security vulnerabilities
if ($http_user_agent ~* ^libwww\-perl/.+) {
    if ($query_string ~ \.) {
        return 403;
    }
}

# Block generic Java-based clients
if ($http_user_agent ~* ^Java/1\.6\.0_04) {
    return 403;
}

# Block generic Mozilla clients
if ($http_user_agent ~* ^Mozilla/5\.0$) {
    return 403;
}

~ is a case-sensitive match, ~* is case-insensitive, & !~ & !~* are their negations.

Unfortunately neither && nor || are valid in nginx if statements, so nesting is the way to go.