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

Adds nextcloud.conf, the thirteenth change. Nextcloud's WebDAV paths allow
PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, REPORT, SEARCH, LOCK and UNLOCK. 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, a share's note, a status and a document's text also skip the rules
that refused ordinary sentences, and the document the two that refused a shell
code block, so "; wget" reaches Nextcloud there. Requests recorded from
Nextcloud 35.0.2, its web pages, sync client 3.16.7 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 twelve changes sww
+// body while SWW_WAF_BODY_LIMIT is set, with the thirteen 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.
@@ -34,8 +34,9 @@ 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, mediawikiExclusions for the sixth, and
-// mastodonExclusions for the seventh.
+// drupalExclusions for the fifth, mediawikiExclusions for the sixth,
+// mastodonExclusions for the seventh, and nextcloudExclusions for the
+// eighth.
 // 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
@@ -95,7 +96,10 @@ SecRule ARGUMENTS_LIMIT_REACHED "@eq 1" "id:900300,phase:2,pass,\
 # So does the eleventh.
 %s
 
-# And the twelfth.
+# So does the twelfth.
+%s
+
+# And the thirteenth.
 %s
 
 # The sixth: only the rules for requests are loaded, and no response is
@@ -217,6 +221,14 @@ var mediawikiExclusions string
 //go:embed mastodon.conf
 var mastodonExclusions string
 
+// nextcloudExclusions are the thirteenth 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.
 //
@@ -330,7 +342,7 @@ type CoreRuleSet struct {
 	bodyLimit int64
 }
 
-// New returns the Core Rule Set with the twelve changes, at params'
+// New returns the Core Rule Set with the thirteen 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
@@ -359,7 +371,7 @@ func New(params Params) (*CoreRuleSet, error) {
 
 	text := fmt.Sprintf(directives, params.ParanoiaLevel, body, exclusions,
 		giteaExclusions, wordpressExclusions, drupalExclusions,
-		mediawikiExclusions, mastodonExclusions)
+		mediawikiExclusions, mastodonExclusions, nextcloudExclusions)
 
 	if len(params.DisabledRules) > 0 {
 		ids := make([]string, len(params.DisabledRules))