consul/agent/xds/rbac.go

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package xds
import (
"fmt"
"sort"
"strings"
envoy_listener_v3 "github.com/envoyproxy/go-control-plane/envoy/config/listener/v3"
envoy_rbac_v3 "github.com/envoyproxy/go-control-plane/envoy/config/rbac/v3"
envoy_route_v3 "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
envoy_http_header_to_meta_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/header_to_metadata/v3"
envoy_http_rbac_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/rbac/v3"
envoy_http_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/network/http_connection_manager/v3"
envoy_network_rbac_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/network/rbac/v3"
envoy_matcher_v3 "github.com/envoyproxy/go-control-plane/envoy/type/matcher/v3"
"github.com/hashicorp/consul/agent/connect"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/proto/private/pbpeering"
)
func makeRBACNetworkFilter(
intentions structs.Intentions,
intentionDefaultAllow bool,
localInfo rbacLocalInfo,
peerTrustBundles []*pbpeering.PeeringTrustBundle,
) (*envoy_listener_v3.Filter, error) {
rules := makeRBACRules(intentions, intentionDefaultAllow, localInfo, false, peerTrustBundles)
cfg := &envoy_network_rbac_v3.RBAC{
StatPrefix: "connect_authz",
Rules: rules,
}
return makeFilter("envoy.filters.network.rbac", cfg)
}
func makeRBACHTTPFilter(
intentions structs.Intentions,
intentionDefaultAllow bool,
localInfo rbacLocalInfo,
peerTrustBundles []*pbpeering.PeeringTrustBundle,
) (*envoy_http_v3.HttpFilter, error) {
rules := makeRBACRules(intentions, intentionDefaultAllow, localInfo, true, peerTrustBundles)
cfg := &envoy_http_rbac_v3.RBAC{
Rules: rules,
}
return makeEnvoyHTTPFilter("envoy.filters.http.rbac", cfg)
}
func intentionListToIntermediateRBACForm(
intentions structs.Intentions,
localInfo rbacLocalInfo,
isHTTP bool,
trustBundlesByPeer map[string]*pbpeering.PeeringTrustBundle,
) []*rbacIntention {
sort.Sort(structs.IntentionPrecedenceSorter(intentions))
// Omit any lower-precedence intentions that share the same source.
intentions = removeSameSourceIntentions(intentions)
rbacIxns := make([]*rbacIntention, 0, len(intentions))
for _, ixn := range intentions {
// trustBundle is only applicable to imported services
trustBundle, ok := trustBundlesByPeer[ixn.SourcePeer]
if ixn.SourcePeer != "" && !ok {
// If the intention defines a source peer, we expect to
// see a trust bundle. Otherwise the config snapshot may
// not have yet received the bundles and we fail silently
continue
}
rixn := intentionToIntermediateRBACForm(ixn, localInfo, isHTTP, trustBundle)
rbacIxns = append(rbacIxns, rixn)
}
return rbacIxns
}
func removeSourcePrecedence(rbacIxns []*rbacIntention, intentionDefaultAction intentionAction, localInfo rbacLocalInfo) []*rbacIntention {
if len(rbacIxns) == 0 {
return nil
}
// Remove source precedence:
//
// First walk backwards and add each intention to all subsequent statements
// (via AND NOT $x).
//
// If it is L4 and has the same action as the default intention action then
// mark the rule itself for erasure.
numRetained := 0
for i := len(rbacIxns) - 1; i >= 0; i-- {
for j := i + 1; j < len(rbacIxns); j++ {
if rbacIxns[j].Skip {
continue
}
// [i] is the intention candidate that we are distributing
// [j] is the thing to maybe NOT [i] from
if ixnSourceMatches(rbacIxns[i].Source, rbacIxns[j].Source) {
rbacIxns[j].NotSources = append(rbacIxns[j].NotSources, rbacIxns[i].Source)
}
}
if rbacIxns[i].Action == intentionDefaultAction {
// Lower precedence intentions that match the default intention
// action are skipped, since they're handled by the default
// catch-all.
rbacIxns[i].Skip = true // mark for deletion
} else {
numRetained++
}
}
// At this point precedence doesn't matter for the source element.
// Remove skipped intentions and also compute the final Principals for each
// intention.
out := make([]*rbacIntention, 0, numRetained)
for _, rixn := range rbacIxns {
if rixn.Skip {
continue
}
rixn.ComputedPrincipal = rixn.FlattenPrincipal(localInfo)
out = append(out, rixn)
}
return out
}
func removeIntentionPrecedence(rbacIxns []*rbacIntention, intentionDefaultAction intentionAction, localInfo rbacLocalInfo) []*rbacIntention {
// Remove source precedence. After this completes precedence doesn't matter
// between any two intentions.
rbacIxns = removeSourcePrecedence(rbacIxns, intentionDefaultAction, localInfo)
numRetained := 0
for _, rbacIxn := range rbacIxns {
// Remove permission precedence. After this completes precedence
// doesn't matter between any two permissions on this intention.
rbacIxn.Permissions = removePermissionPrecedence(rbacIxn.Permissions, intentionDefaultAction)
if rbacIxn.Action == intentionActionLayer7 && len(rbacIxn.Permissions) == 0 {
// All of the permissions must have had the default action type and
// were removed. Mark this for removal below.
rbacIxn.Skip = true
} else {
numRetained++
}
}
if numRetained == len(rbacIxns) {
return rbacIxns
}
// We previously used the absence of permissions (above) as a signal to
// mark the entire intention for removal. Now do the deletions.
out := make([]*rbacIntention, 0, numRetained)
for _, rixn := range rbacIxns {
if !rixn.Skip {
out = append(out, rixn)
}
}
return out
}
func removePermissionPrecedence(perms []*rbacPermission, intentionDefaultAction intentionAction) []*rbacPermission {
if len(perms) == 0 {
return nil
}
// First walk backwards and add each permission to all subsequent
// statements (via AND NOT $x).
//
// If it has the same action as the default intention action then mark the
// permission itself for erasure.
numRetained := 0
for i := len(perms) - 1; i >= 0; i-- {
for j := i + 1; j < len(perms); j++ {
if perms[j].Skip {
continue
}
// [i] is the permission candidate that we are distributing
// [j] is the thing to maybe NOT [i] from
perms[j].NotPerms = append(
perms[j].NotPerms,
perms[i].Perm,
)
}
if perms[i].Action == intentionDefaultAction {
// Lower precedence permissions that match the default intention
// action are skipped, since they're handled by the default
// catch-all.
perms[i].Skip = true // mark for deletion
} else {
numRetained++
}
}
// Remove skipped permissions and also compute the final Permissions for each item.
out := make([]*rbacPermission, 0, numRetained)
for _, perm := range perms {
if perm.Skip {
continue
}
perm.ComputedPermission = perm.Flatten()
out = append(out, perm)
}
return out
}
func intentionToIntermediateRBACForm(
ixn *structs.Intention,
localInfo rbacLocalInfo,
isHTTP bool,
bundle *pbpeering.PeeringTrustBundle,
) *rbacIntention {
rixn := &rbacIntention{
Source: rbacService{
ServiceName: ixn.SourceServiceName(),
Peer: ixn.SourcePeer,
TrustDomain: localInfo.trustDomain,
},
Precedence: ixn.Precedence,
}
// imported services will have addition metadata used to override SpiffeID creation
if bundle != nil {
rixn.Source.ExportedPartition = bundle.ExportedPartition
rixn.Source.TrustDomain = bundle.TrustDomain
}
if len(ixn.Permissions) > 0 {
if isHTTP {
rixn.Action = intentionActionLayer7
rixn.Permissions = make([]*rbacPermission, 0, len(ixn.Permissions))
for _, perm := range ixn.Permissions {
rixn.Permissions = append(rixn.Permissions, &rbacPermission{
Definition: perm,
Action: intentionActionFromString(perm.Action),
Perm: convertPermission(perm),
})
}
} else {
// In case L7 intentions slip through to here, treat them as deny intentions.
rixn.Action = intentionActionDeny
}
} else {
rixn.Action = intentionActionFromString(ixn.Action)
}
return rixn
}
type intentionAction int
const (
intentionActionDeny intentionAction = iota
intentionActionAllow
intentionActionLayer7
)
func intentionActionFromBool(v bool) intentionAction {
if v {
return intentionActionAllow
} else {
return intentionActionDeny
}
}
func intentionActionFromString(s structs.IntentionAction) intentionAction {
if s == structs.IntentionActionAllow {
return intentionActionAllow
}
return intentionActionDeny
}
type rbacService struct {
structs.ServiceName
// Peer, ExportedPartition, and TrustDomain are
// only applicable to imported services and are
// used to override SPIFFEID fields.
Peer string
ExportedPartition string
TrustDomain string
}
type rbacIntention struct {
Source rbacService
NotSources []rbacService
Action intentionAction
Permissions []*rbacPermission
Precedence int
// Skip is field used to indicate that this intention can be deleted in the
// final pass. Items marked as true should generally not escape the method
// that marked them.
Skip bool
ComputedPrincipal *envoy_rbac_v3.Principal
}
func (r *rbacIntention) FlattenPrincipal(localInfo rbacLocalInfo) *envoy_rbac_v3.Principal {
if !localInfo.expectXFCC {
return r.flattenPrincipalFromCert()
} else if r.Source.Peer == "" {
// NOTE: ixnSourceMatches should enforce that all of Source and NotSources
// are peered or not-peered, so we only need to look at the Source element.
return r.flattenPrincipalFromCert() // intention is not relevant to peering
}
// If this intention is an L7 peered one, then it is exclusively resolvable
// using XFCC, rather than the TLS SAN field.
fromXFCC := r.flattenPrincipalFromXFCC()
// Use of the XFCC one is gated on coming directly from our own gateways.
gwIDPattern := makeSpiffeMeshGatewayPattern(localInfo.trustDomain, localInfo.partition)
return andPrincipals([]*envoy_rbac_v3.Principal{
authenticatedPatternPrincipal(gwIDPattern),
fromXFCC,
})
}
func (r *rbacIntention) flattenPrincipalFromCert() *envoy_rbac_v3.Principal {
r.NotSources = simplifyNotSourceSlice(r.NotSources)
if len(r.NotSources) == 0 {
return idPrincipal(r.Source)
}
andIDs := make([]*envoy_rbac_v3.Principal, 0, len(r.NotSources)+1)
andIDs = append(andIDs, idPrincipal(r.Source))
for _, src := range r.NotSources {
andIDs = append(andIDs, notPrincipal(
idPrincipal(src),
))
}
return andPrincipals(andIDs)
}
func (r *rbacIntention) flattenPrincipalFromXFCC() *envoy_rbac_v3.Principal {
r.NotSources = simplifyNotSourceSlice(r.NotSources)
if len(r.NotSources) == 0 {
return xfccPrincipal(r.Source)
}
andIDs := make([]*envoy_rbac_v3.Principal, 0, len(r.NotSources)+1)
andIDs = append(andIDs, xfccPrincipal(r.Source))
for _, src := range r.NotSources {
andIDs = append(andIDs, notPrincipal(
xfccPrincipal(src),
))
}
return andPrincipals(andIDs)
}
type rbacPermission struct {
Definition *structs.IntentionPermission
Action intentionAction
Perm *envoy_rbac_v3.Permission
NotPerms []*envoy_rbac_v3.Permission
// Skip is field used to indicate that this permission can be deleted in
// the final pass. Items marked as true should generally not escape the
// method that marked them.
Skip bool
ComputedPermission *envoy_rbac_v3.Permission
}
func (p *rbacPermission) Flatten() *envoy_rbac_v3.Permission {
if len(p.NotPerms) == 0 {
return p.Perm
}
parts := make([]*envoy_rbac_v3.Permission, 0, len(p.NotPerms)+1)
parts = append(parts, p.Perm)
for _, notPerm := range p.NotPerms {
parts = append(parts, notPermission(notPerm))
}
return andPermissions(parts)
}
// simplifyNotSourceSlice will collapse NotSources elements together if any element is
// a subset of another.
// For example "default/web" is a subset of "default/*" because it is covered by the wildcard.
func simplifyNotSourceSlice(notSources []rbacService) []rbacService {
if len(notSources) <= 1 {
return notSources
}
// Sort, keeping the least wildcarded elements first.
// More specific elements have a higher precedence over more wildcarded elements.
sort.SliceStable(notSources, func(i, j int) bool {
return countWild(notSources[i]) < countWild(notSources[j])
})
keep := make([]rbacService, 0, len(notSources))
for i := 0; i < len(notSources); i++ {
si := notSources[i]
remove := false
for j := i + 1; j < len(notSources); j++ {
sj := notSources[j]
if ixnSourceMatches(si, sj) {
remove = true
break
}
}
if !remove {
keep = append(keep, si)
}
}
return keep
}
type rbacLocalInfo struct {
trustDomain string
datacenter string
partition string
expectXFCC bool
}
// makeRBACRules translates Consul intentions into RBAC Policies for Envoy.
//
// Consul lets you define up to 9 different kinds of intentions that apply at
// different levels of precedence (this is limited to 4 if not using Consul
// Enterprise). Each intention in this flat list (sorted by precedence) can either
// be an allow rule or a deny rule. Heres a concrete example of this at work:
//
// intern/trusted-app => billing/payment-svc : ALLOW (prec=9)
// intern/* => billing/payment-svc : DENY (prec=8)
// */* => billing/payment-svc : ALLOW (prec=7)
// ::: ACL default policy ::: : DENY (prec=N/A)
//
// In contrast, Envoy lets you either configure a filter to be based on an
// allow-list or a deny-list based on the action attribute of the RBAC rules
// struct.
//
// On the surface it would seem that the configuration model of Consul
// intentions is incompatible with that of Envoys RBAC engine. For any given
// destination service Consuls model requires evaluating a list of rules and
// short circuiting later rules once an earlier rule matches. After a rule is
// found to match then we decide if it is allow/deny. Envoy on the other hand
// requires the rules to express all conditions to allow access or all conditions
// to deny access.
//
// Despite the surface incompatibility it is possible to marry these two
// models. For clarity Ill rewrite the earlier example intentions in an
// abbreviated form:
//
// A : ALLOW
// B : DENY
// C : ALLOW
// <default> : DENY
//
// 1. Given that the overall intention default is set to deny, we start by
// choosing to build an allow-list in Envoy (this is also the variant that I find
// easier to think about).
// 2. Next we traverse the list in precedence order (top down) and any DENY
// intentions are combined with later intentions using logical operations.
// 3. Now that all of the intentions result in the same action (allow) we have
// successfully removed precedence and we can express this in as a set of Envoy
// RBAC policies.
//
// After this the earlier A/B/C/default list becomes:
//
// A : ALLOW
// C AND NOT(B) : ALLOW
// <default> : DENY
//
// Which really is just an allow-list of [A, C AND NOT(B)]
func makeRBACRules(
intentions structs.Intentions,
intentionDefaultAllow bool,
localInfo rbacLocalInfo,
isHTTP bool,
peerTrustBundles []*pbpeering.PeeringTrustBundle,
) *envoy_rbac_v3.RBAC {
// TODO(banks,rb): Implement revocation list checking?
// TODO(peering): mkeeler asked that these maps come from proxycfg instead of
// being constructed in xds to save memory allocation and gc pressure. Low priority.
trustBundlesByPeer := make(map[string]*pbpeering.PeeringTrustBundle, len(peerTrustBundles))
for _, ptb := range peerTrustBundles {
trustBundlesByPeer[ptb.PeerName] = ptb
}
if isHTTP && len(peerTrustBundles) > 0 {
for _, ixn := range intentions {
if ixn.SourcePeer != "" {
localInfo.expectXFCC = true
break
}
}
}
// First build up just the basic principal matches.
rbacIxns := intentionListToIntermediateRBACForm(intentions, localInfo, isHTTP, trustBundlesByPeer)
// Normalize: if we are in default-deny then all intentions must be allows and vice versa
intentionDefaultAction := intentionActionFromBool(intentionDefaultAllow)
var rbacAction envoy_rbac_v3.RBAC_Action
if intentionDefaultAllow {
// The RBAC policies deny access to principals. The rest is allowed.
// This is block-list style access control.
rbacAction = envoy_rbac_v3.RBAC_DENY
} else {
// The RBAC policies grant access to principals. The rest is denied.
// This is safe-list style access control. This is the default type.
rbacAction = envoy_rbac_v3.RBAC_ALLOW
}
// Remove source and permissions precedence.
rbacIxns = removeIntentionPrecedence(rbacIxns, intentionDefaultAction, localInfo)
// For L4: we should generate one big Policy listing all Principals
// For L7: we should generate one Policy per Principal and list all of the Permissions
rbac := &envoy_rbac_v3.RBAC{
Action: rbacAction,
Policies: make(map[string]*envoy_rbac_v3.Policy),
}
var principalsL4 []*envoy_rbac_v3.Principal
for i, rbacIxn := range rbacIxns {
if rbacIxn.Action == intentionActionLayer7 {
if len(rbacIxn.Permissions) == 0 {
panic("invalid state: L7 intention has no permissions")
}
if !isHTTP {
panic("invalid state: L7 permissions present for TCP service")
}
// For L7: we should generate one Policy per Principal and list all of the Permissions
policy := &envoy_rbac_v3.Policy{
Principals: optimizePrincipals([]*envoy_rbac_v3.Principal{rbacIxn.ComputedPrincipal}),
Permissions: make([]*envoy_rbac_v3.Permission, 0, len(rbacIxn.Permissions)),
}
for _, perm := range rbacIxn.Permissions {
policy.Permissions = append(policy.Permissions, perm.ComputedPermission)
}
rbac.Policies[fmt.Sprintf("consul-intentions-layer7-%d", i)] = policy
} else {
// For L4: we should generate one big Policy listing all Principals
principalsL4 = append(principalsL4, rbacIxn.ComputedPrincipal)
}
}
if len(principalsL4) > 0 {
rbac.Policies["consul-intentions-layer4"] = &envoy_rbac_v3.Policy{
Principals: optimizePrincipals(principalsL4),
Permissions: []*envoy_rbac_v3.Permission{anyPermission()},
}
}
if len(rbac.Policies) == 0 {
rbac.Policies = nil
}
return rbac
}
func optimizePrincipals(orig []*envoy_rbac_v3.Principal) []*envoy_rbac_v3.Principal {
// If they are all ORs, then OR them together.
var orIds []*envoy_rbac_v3.Principal
for _, p := range orig {
or, ok := p.Identifier.(*envoy_rbac_v3.Principal_OrIds)
if !ok {
return orig
}
orIds = append(orIds, or.OrIds.Ids...)
}
return []*envoy_rbac_v3.Principal{orPrincipals(orIds)}
}
// removeSameSourceIntentions will iterate over intentions and remove any lower precedence
// intentions that share the same source. Intentions are sorted by descending precedence
// so once a source has been seen, additional intentions with the same source can be dropped.
//
// Example for the default/web service:
// input: [(backend/* -> default/web), (backend/* -> default/*)]
// output: [(backend/* -> default/web)]
//
// (backend/* -> default/*) was dropped because it is already known that any service
// in the backend namespace can target default/web.
func removeSameSourceIntentions(intentions structs.Intentions) structs.Intentions {
if len(intentions) < 2 {
return intentions
}
var (
out = make(structs.Intentions, 0, len(intentions))
changed = false
seenSource = make(map[structs.PeeredServiceName]struct{})
)
for _, ixn := range intentions {
psn := structs.PeeredServiceName{
ServiceName: ixn.SourceServiceName(),
Peer: ixn.SourcePeer,
}
if _, ok := seenSource[psn]; ok {
// A higher precedence intention already used this exact source
// definition with a different destination.
changed = true
continue
}
seenSource[psn] = struct{}{}
out = append(out, ixn)
}
if !changed {
return intentions
}
return out
}
// ixnSourceMatches determines if the 'tester' service name is matched by the
// 'against' service name via wildcard rules.
//
// For instance:
// - (web, api) => false, because these have no wildcards
// - (web, *) => true, because "all services" includes "web"
// - (default/web, default/*) => true, because "all services in the default NS" includes "default/web"
// - (default/*, */*) => true, "any service in any NS" includes "all services in the default NS"
// - (default/default/*, other/*/*) => false, "any service in "other" partition" does NOT include services in the default partition"
//
// Peer and partition must be exact names and cannot be compared with wildcards.
func ixnSourceMatches(tester, against rbacService) bool {
// We assume that we can't have the same intention twice before arriving
// here.
numWildTester := countWild(tester)
numWildAgainst := countWild(against)
if numWildTester == numWildAgainst {
return false
} else if numWildTester > numWildAgainst {
return false
}
matchesAP := tester.PartitionOrDefault() == against.PartitionOrDefault()
matchesPeer := tester.Peer == against.Peer
matchesNS := tester.NamespaceOrDefault() == against.NamespaceOrDefault() || against.NamespaceOrDefault() == structs.WildcardSpecifier
matchesName := tester.Name == against.Name || against.Name == structs.WildcardSpecifier
return matchesAP && matchesPeer && matchesNS && matchesName
}
// countWild counts the number of wildcard values in the given namespace and name.
func countWild(src rbacService) int {
// If Partition is wildcard, panic because it's not supported
if src.PartitionOrDefault() == structs.WildcardSpecifier {
panic("invalid state: intention references wildcard partition")
}
if src.Peer == structs.WildcardSpecifier {
panic("invalid state: intention references wildcard peer")
}
// If NS is wildcard, it must be 2 since wildcards only follow exact
if src.NamespaceOrDefault() == structs.WildcardSpecifier {
return 2
}
// Same reasoning as above, a wildcard can only follow an exact value
// and an exact value cannot follow a wildcard, so if name is a wildcard
// we must have exactly one.
if src.Name == structs.WildcardSpecifier {
return 1
}
return 0
}
func andPrincipals(ids []*envoy_rbac_v3.Principal) *envoy_rbac_v3.Principal {
return &envoy_rbac_v3.Principal{
Identifier: &envoy_rbac_v3.Principal_AndIds{
AndIds: &envoy_rbac_v3.Principal_Set{
Ids: ids,
},
},
}
}
func orPrincipals(ids []*envoy_rbac_v3.Principal) *envoy_rbac_v3.Principal {
return &envoy_rbac_v3.Principal{
Identifier: &envoy_rbac_v3.Principal_OrIds{
OrIds: &envoy_rbac_v3.Principal_Set{
Ids: ids,
},
},
}
}
func notPrincipal(id *envoy_rbac_v3.Principal) *envoy_rbac_v3.Principal {
return &envoy_rbac_v3.Principal{
Identifier: &envoy_rbac_v3.Principal_NotId{
NotId: id,
},
}
}
func idPrincipal(src rbacService) *envoy_rbac_v3.Principal {
pattern := makeSpiffePattern(src)
return authenticatedPatternPrincipal(pattern)
}
func authenticatedPatternPrincipal(pattern string) *envoy_rbac_v3.Principal {
return &envoy_rbac_v3.Principal{
Identifier: &envoy_rbac_v3.Principal_Authenticated_{
Authenticated: &envoy_rbac_v3.Principal_Authenticated{
PrincipalName: &envoy_matcher_v3.StringMatcher{
MatchPattern: &envoy_matcher_v3.StringMatcher_SafeRegex{
SafeRegex: makeEnvoyRegexMatch(pattern),
},
},
},
},
}
}
func xfccPrincipal(src rbacService) *envoy_rbac_v3.Principal {
// Same match we normally would use.
idPattern := makeSpiffePattern(src)
// Remove the leading ^ and trailing $.
idPattern = idPattern[1 : len(idPattern)-1]
// Anchor to the first XFCC component
pattern := `^[^,]+;URI=` + idPattern + `(?:,.*)?$`
// By=spiffe://8c7db6d3-e4ee-aa8c-488c-dbedd3772b78.consul/gateway/mesh/dc/dc2;
// Hash=2a2db78ac351a05854a0abd350631bf98cc0eb827d21f4ed5935ccd287779eb6;
// Cert="-----BEGIN%20CERTIFICATE-----<SNIP>";
// Chain="-----BEGIN%20CERTIFICATE-----<SNIP>";
// Subject="";
// URI=spiffe://5583c38e-c1c0-fd1e-2079-170bb2f396ad.consul/ns/default/dc/dc1/svc/pong,
return &envoy_rbac_v3.Principal{
Identifier: &envoy_rbac_v3.Principal_Header{
Header: &envoy_route_v3.HeaderMatcher{
Name: "x-forwarded-client-cert",
HeaderMatchSpecifier: &envoy_route_v3.HeaderMatcher_StringMatch{
StringMatch: &envoy_matcher_v3.StringMatcher{
MatchPattern: &envoy_matcher_v3.StringMatcher_SafeRegex{
SafeRegex: makeEnvoyRegexMatch(pattern),
},
},
},
},
},
}
}
const anyPath = `[^/]+`
const trustDomain = anyPath + "." + anyPath
// downstreamServiceIdentityMatcher needs to match XFCC headers in two cases:
// 1. Requests to cluster peered services through a mesh gateway. In this case, the XFCC header looks like the following (I added a new line after each ; for readability)
// By=spiffe://950df996-caef-ddef-ec5f-8d18a153b7b2.consul/gateway/mesh/dc/alpha;
// Hash=...;
// Cert=...;
// Chain=...;
// Subject="";
// URI=spiffe://c7e1d24a-eed8-10a3-286a-52bdb6b6a6fd.consul/ns/default/dc/primary/svc/s1,By=spiffe://950df996-caef-ddef-ec5f-8d18a153b7b2.consul/ns/default/dc/alpha/svc/s2;
// Hash=...;
// Cert=...;
// Chain=...;
// Subject="";
// URI=spiffe://950df996-caef-ddef-ec5f-8d18a153b7b2.consul/gateway/mesh/dc/alpha
//
// 2. Requests directly to another service
// By=spiffe://ae9dbea8-c1dd-7356-b211-c564f7917100.consul/ns/default/dc/primary/svc/s2;
// Hash=396218588ebc1655d32a49b68cedd6b66b9de7b3d69d0c0451bc5818132377d0;
// Cert=...;
// Chain=...;
// Subject="";
// URI=spiffe://ae9dbea8-c1dd-7356-b211-c564f7917100.consul/ns/default/dc/primary/svc/s1
//
// In either case, the regex matches the downstream service's spiffe id because mesh gateways use a different spiffe id format.
// Envoy requires us to include the trailing and leading .* to properly extract the properly submatch.
const downstreamServiceIdentityMatcher = ".*URI=spiffe://(" + trustDomain +
")(?:/ap/(" + anyPath +
"))?/ns/(" + anyPath +
")/dc/(" + anyPath +
")/svc/([^/;,]+).*"
func parseXFCCToDynamicMetaHTTPFilter() (*envoy_http_v3.HttpFilter, error) {
var rules []*envoy_http_header_to_meta_v3.Config_Rule
fields := []struct {
name string
sub string
}{
{
name: "trust-domain",
sub: `\1`,
},
{
name: "partition",
sub: `\2`,
},
{
name: "namespace",
sub: `\3`,
},
{
name: "datacenter",
sub: `\4`,
},
{
name: "service",
sub: `\5`,
},
}
for _, f := range fields {
rules = append(rules, &envoy_http_header_to_meta_v3.Config_Rule{
Header: "x-forwarded-client-cert",
OnHeaderPresent: &envoy_http_header_to_meta_v3.Config_KeyValuePair{
MetadataNamespace: "consul",
Key: f.name,
RegexValueRewrite: &envoy_matcher_v3.RegexMatchAndSubstitute{
Pattern: &envoy_matcher_v3.RegexMatcher{
Regex: downstreamServiceIdentityMatcher,
EngineType: &envoy_matcher_v3.RegexMatcher_GoogleRe2{
GoogleRe2: &envoy_matcher_v3.RegexMatcher_GoogleRE2{},
},
},
Substitution: f.sub,
},
},
})
}
cfg := &envoy_http_header_to_meta_v3.Config{RequestRules: rules}
return makeEnvoyHTTPFilter("envoy.filters.http.header_to_metadata", cfg)
}
func makeSpiffePattern(src rbacService) string {
var (
host = src.TrustDomain
ap = src.PartitionOrDefault()
ns = src.NamespaceOrDefault()
svc = src.Name
)
// Validate proper wildcarding
if ns == structs.WildcardSpecifier && svc != structs.WildcardSpecifier {
panic(fmt.Sprintf("not possible to have a wildcarded namespace %q but an exact service %q", ns, svc))
}
if ap == structs.WildcardSpecifier {
panic("not possible to have a wildcarded source partition")
}
if src.Peer == structs.WildcardSpecifier {
panic("not possible to have a wildcarded source peer")
}
// Match on any namespace or service if it is a wildcard, or on a specific value otherwise.
if ns == structs.WildcardSpecifier {
ns = anyPath
}
if svc == structs.WildcardSpecifier {
svc = anyPath
}
// If service is imported from a peer, the SpiffeID must
// refer to its remote partition and trust domain.
if src.Peer != "" {
ap = src.ExportedPartition
host = src.TrustDomain
}
id := connect.SpiffeIDService{
Namespace: ns,
Service: svc,
Host: host,
// Datacenter is not verified by RBAC, so we match on any value.
Datacenter: anyPath,
// Partition can only ever be an exact value.
Partition: ap,
}
return fmt.Sprintf(`^%s://%s%s$`, id.URI().Scheme, id.Host, id.URI().Path)
}
func makeSpiffeMeshGatewayPattern(gwTrustDomain, gwPartition string) string {
id := connect.SpiffeIDMeshGateway{
Host: gwTrustDomain,
Partition: gwPartition,
// Datacenter is not verified by RBAC, so we match on any value.
Datacenter: anyPath,
}
return fmt.Sprintf(`^%s://%s%s$`, id.URI().Scheme, id.Host, id.URI().Path)
}
func anyPermission() *envoy_rbac_v3.Permission {
return &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_Any{Any: true},
}
}
func convertPermission(perm *structs.IntentionPermission) *envoy_rbac_v3.Permission {
// NOTE: this does not do anything with perm.Action
if perm.HTTP == nil {
return anyPermission()
}
var parts []*envoy_rbac_v3.Permission
switch {
case perm.HTTP.PathExact != "":
parts = append(parts, &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_UrlPath{
UrlPath: &envoy_matcher_v3.PathMatcher{
Rule: &envoy_matcher_v3.PathMatcher_Path{
Path: &envoy_matcher_v3.StringMatcher{
MatchPattern: &envoy_matcher_v3.StringMatcher_Exact{
Exact: perm.HTTP.PathExact,
},
},
},
},
},
})
case perm.HTTP.PathPrefix != "":
parts = append(parts, &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_UrlPath{
UrlPath: &envoy_matcher_v3.PathMatcher{
Rule: &envoy_matcher_v3.PathMatcher_Path{
Path: &envoy_matcher_v3.StringMatcher{
MatchPattern: &envoy_matcher_v3.StringMatcher_Prefix{
Prefix: perm.HTTP.PathPrefix,
},
},
},
},
},
})
case perm.HTTP.PathRegex != "":
parts = append(parts, &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_UrlPath{
UrlPath: &envoy_matcher_v3.PathMatcher{
Rule: &envoy_matcher_v3.PathMatcher_Path{
Path: &envoy_matcher_v3.StringMatcher{
MatchPattern: &envoy_matcher_v3.StringMatcher_SafeRegex{
SafeRegex: makeEnvoyRegexMatch(perm.HTTP.PathRegex),
},
},
},
},
},
})
}
for _, hdr := range perm.HTTP.Header {
eh := &envoy_route_v3.HeaderMatcher{
Name: hdr.Name,
}
switch {
case hdr.Exact != "":
eh.HeaderMatchSpecifier = &envoy_route_v3.HeaderMatcher_ExactMatch{
ExactMatch: hdr.Exact,
}
case hdr.Regex != "":
eh.HeaderMatchSpecifier = &envoy_route_v3.HeaderMatcher_SafeRegexMatch{
SafeRegexMatch: makeEnvoyRegexMatch(hdr.Regex),
}
case hdr.Prefix != "":
eh.HeaderMatchSpecifier = &envoy_route_v3.HeaderMatcher_PrefixMatch{
PrefixMatch: hdr.Prefix,
}
case hdr.Suffix != "":
eh.HeaderMatchSpecifier = &envoy_route_v3.HeaderMatcher_SuffixMatch{
SuffixMatch: hdr.Suffix,
}
case hdr.Present:
eh.HeaderMatchSpecifier = &envoy_route_v3.HeaderMatcher_PresentMatch{
PresentMatch: true,
}
default:
continue // skip this impossible situation
}
if hdr.Invert {
eh.InvertMatch = true
}
parts = append(parts, &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_Header{
Header: eh,
},
})
}
if len(perm.HTTP.Methods) > 0 {
methodHeaderRegex := strings.Join(perm.HTTP.Methods, "|")
eh := &envoy_route_v3.HeaderMatcher{
Name: ":method",
HeaderMatchSpecifier: &envoy_route_v3.HeaderMatcher_SafeRegexMatch{
SafeRegexMatch: makeEnvoyRegexMatch(methodHeaderRegex),
},
}
parts = append(parts, &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_Header{
Header: eh,
},
})
}
// NOTE: if for some reason we errantly allow a permission to be defined
// with a body of "http{}" then we'll end up treating that like "ANY" here.
return andPermissions(parts)
}
func notPermission(perm *envoy_rbac_v3.Permission) *envoy_rbac_v3.Permission {
return &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_NotRule{NotRule: perm},
}
}
func andPermissions(perms []*envoy_rbac_v3.Permission) *envoy_rbac_v3.Permission {
switch len(perms) {
case 0:
return anyPermission()
case 1:
return perms[0]
default:
return &envoy_rbac_v3.Permission{
Rule: &envoy_rbac_v3.Permission_AndRules{
AndRules: &envoy_rbac_v3.Permission_Set{
Rules: perms,
},
},
}
}
}