Ban lists: where Guard and fail2ban ban addresses

A program bans an address (every port, or a protocol's ports) for a
time; the ban list says what it is kept from: the firewall, some hosts
behind it, or everything. Bans drop ahead of every rule, close the
address's connections, group IPv6 by /64, are kept in the database
across restarts and audited. Never banned: the inside, the firewall's
own addresses, the caller, the list's never. bans grant (bans:write:LIST),
hc banlist/bans/ban/unban, Traffic -> Bans, a fail2ban action in contrib/,
and failed logins and refused tokens logged for Guard and fail2ban.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/auth/auth.go

@@ -147,13 +147,14 @@ func NewSessionID() (id, csrf string) {
 const (
 	ResConfig = "config" // the firewall configuration, its history and imports
 	ResSets   = "sets"   // dynamic sets' entries (a grant may name the sets)
+	ResBans   = "bans"   // ban lists' bans (a grant may name the lists)
 	ResLog    = "log"    // counters, the drop log and the status
 	ResAudit  = "audit"  // the audit log
 	ResAll    = "*"
 )
 
 // Resources lists them in display order.
-var Resources = []string{ResConfig, ResSets, ResLog, ResAudit}
+var Resources = []string{ResConfig, ResSets, ResBans, ResLog, ResAudit}
 
 // Access levels.
 const (
@@ -163,8 +164,8 @@ const (
 
 // Roles are ready-made sets of grants.
 var Roles = map[string][]model.Grant{
-	"viewer":   {{Resource: ResConfig, Access: Read}, {Resource: ResSets, Access: Read}, {Resource: ResLog, Access: Read}},
-	"operator": {{Resource: ResConfig, Access: Write}, {Resource: ResSets, Access: Write}, {Resource: ResLog, Access: Read}, {Resource: ResAudit, Access: Read}},
+	"viewer":   {{Resource: ResConfig, Access: Read}, {Resource: ResSets, Access: Read}, {Resource: ResBans, Access: Read}, {Resource: ResLog, Access: Read}},
+	"operator": {{Resource: ResConfig, Access: Write}, {Resource: ResSets, Access: Write}, {Resource: ResBans, Access: Write}, {Resource: ResLog, Access: Read}, {Resource: ResAudit, Access: Read}},
 	"log":      {{Resource: ResLog, Access: Read}},
 }
 
@@ -179,12 +180,13 @@ func RoleNames() []string {
 }
 
 // ParseGrant reads "resource:access" ("log:read", "*:write"), and for
-// sets optionally the sets it is limited to ("sets:write:guest,portal").
+// sets and bans optionally the sets or ban lists it is limited to
+// ("sets:write:guest,portal", "bans:write:web").
 func ParseGrant(s string) (model.Grant, error) {
 	parts := strings.SplitN(strings.TrimSpace(s), ":", 3)
 	g := model.Grant{Resource: strings.ToLower(parts[0])}
 	if len(parts) < 2 {
-		return g, fmt.Errorf("grant %q: write it as resource:access, e.g. log:read, or sets:write:SET1,SET2", s)
+		return g, fmt.Errorf("grant %q: write it as resource:access, e.g. log:read, sets:write:SET1,SET2 or bans:write:LIST", s)
 	}
 	g.Access = strings.ToLower(parts[1])
 	if len(parts) == 3 {
@@ -211,8 +213,8 @@ func ValidateGrant(g *model.Grant) error {
 	if g.Access != Read && g.Access != Write {
 		return fmt.Errorf("access must be read or write, not %q", g.Access)
 	}
-	if len(g.Sets) > 0 && g.Resource != ResSets {
-		return fmt.Errorf("only a sets grant can name sets (sets:write:%s)", strings.Join(g.Sets, ","))
+	if len(g.Sets) > 0 && g.Resource != ResSets && g.Resource != ResBans {
+		return fmt.Errorf("only a sets or bans grant can name sets or ban lists (sets:write:%s)", strings.Join(g.Sets, ","))
 	}
 	return nil
 }
@@ -272,20 +274,26 @@ func covers(gs []model.Grant, resource string, write bool) bool {
 
 // CanSet reports whether the principal may read or change the entries of
 // a dynamic set: a sets grant covers it if it names no sets, or names it.
-func (p *Principal) CanSet(name string, write bool) bool {
+func (p *Principal) CanSet(name string, write bool) bool { return p.canNamed(ResSets, name, write) }
+
+// CanBan reports whether the principal may read or change the bans of a
+// ban list: a bans grant covers it if it names no lists, or names it.
+func (p *Principal) CanBan(list string, write bool) bool { return p.canNamed(ResBans, list, write) }
+
+func (p *Principal) canNamed(resource, name string, write bool) bool {
 	if p == nil || p.User == nil {
 		return false
 	}
-	allowed := p.User.Admin || coversSet(p.User.Grants, name, write)
+	allowed := p.User.Admin || coversNamed(p.User.Grants, resource, name, write)
 	if p.Token != nil && p.Token.Grants != nil {
-		allowed = allowed && coversSet(p.Token.Grants, name, write)
+		allowed = allowed && coversNamed(p.Token.Grants, resource, name, write)
 	}
 	return allowed
 }
 
-func coversSet(gs []model.Grant, name string, write bool) bool {
+func coversNamed(gs []model.Grant, resource, name string, write bool) bool {
 	for _, g := range gs {
-		if (g.Resource != ResAll && g.Resource != ResSets) || (write && g.Access != Write) {
+		if (g.Resource != ResAll && g.Resource != resource) || (write && g.Access != Write) {
 			continue
 		}
 		if len(g.Sets) == 0 {