Core Rule Set: Nextcloud's ordinary requests pass by default (closes #240)

Adds nextcloud.conf, the twelfth change. Nextcloud's WebDAV paths allow
PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, REPORT and SEARCH. The account-name
cookie nc_username, and the fields that carry a search, a name, a file name or
a folder on the sign-in page, the Files app, public shares and the OCS API,
skip the four rules that read them as commands or system files. Comments and
the text editor's document skip the two rules for a command after a ";" too;
932235 keeps "; wget" refused. Requests recorded from Nextcloud 35.0.2, its
web pages, sync client 3.16.7 with chunked uploads and the OCS API, pass at
the defaults and while bodies are read.

Model: opus-5-5

internal/coreruleset/coreruleset.go

@@ -1,6 +1,6 @@
 // Package coreruleset runs the OWASP Core Rule Set 4.25.0, through Coraza, on the
 // method, the URL with its query and the headers of a request, and on its
-// body while SWW_WAF_BODY_LIMIT is set, with the eleven changes sww
+// body while SWW_WAF_BODY_LIMIT is set, with the twelve changes sww
 // makes to it and the exclusions in SWW_CORE_RULE_SET_EXCLUSIONS_FILE, as
 // "Attack detection" under "Settings" in SPEC.md describes them. It reads no
 // response.
@@ -34,7 +34,8 @@ import (
 // paranoia level for %d, bodyDirectives for the first %s while
 // SWW_WAF_BODY_LIMIT is set, the exclusions file for the second,
 // giteaExclusions for the third, wordpressExclusions for the fourth,
-// drupalExclusions for the fifth, and mediawikiExclusions for the sixth.
+// drupalExclusions for the fifth, mediawikiExclusions for the sixth, and
+// nextcloudExclusions for the seventh.
 // Each rule sww adds has an id from 900000 to 900999, the ids the
 // Core Rule Set keeps for the rules that set it up, which
 // SWW_WAF_DISABLED_RULES and the exclusions file refuse, so that no
@@ -91,7 +92,10 @@ SecRule ARGUMENTS_LIMIT_REACHED "@eq 1" "id:900300,phase:2,pass,\
 # So does the tenth.
 %s
 
-# And the eleventh.
+# So does the eleventh.
+%s
+
+# And the twelfth.
 %s
 
 # The sixth: only the rules for requests are loaded, and no response is
@@ -206,6 +210,14 @@ var drupalExclusions string
 //go:embed mediawiki.conf
 var mediawikiExclusions string
 
+// nextcloudExclusions are the twelfth change: the fields of Nextcloud's
+// own requests that skip the rules that refused them there, the WebDAV
+// methods it uses, and its cookie of the account's name, as Coraza
+// directives.
+//
+//go:embed nextcloud.conf
+var nextcloudExclusions string
+
 // cookiesNotRead are the cookies the Core Rule Set reads a request
 // without, the rest of the fifth change.
 //
@@ -319,7 +331,7 @@ type CoreRuleSet struct {
 	bodyLimit int64
 }
 
-// New returns the Core Rule Set with the eleven changes, at params'
+// New returns the Core Rule Set with the twelve changes, at params'
 // paranoia level, without the rules it switches off, reading request
 // bodies up to params' limit, and with params' exclusions file loaded
 // before the Core Rule Set's rules. An exclusions file is an error if it
@@ -348,7 +360,7 @@ func New(params Params) (*CoreRuleSet, error) {
 
 	text := fmt.Sprintf(directives, params.ParanoiaLevel, body, exclusions,
 		giteaExclusions, wordpressExclusions, drupalExclusions,
-		mediawikiExclusions)
+		mediawikiExclusions, nextcloudExclusions)
 
 	if len(params.DisabledRules) > 0 {
 		ids := make([]string, len(params.DisabledRules))