Host Volumes Support: Rollup Edition

acl/acl.go

@@ -51,6 +51,13 @@ type ACL struct {
 	// We use an iradix for the purposes of ordered iteration.
 	wildcardNamespaces *iradix.Tree
 
+	// hostVolumes maps a named host volume to a capabilitySet
+	hostVolumes *iradix.Tree
+
+	// wildcardHostVolumes maps a glob pattern of host volume names to a capabilitySet
+	// We use an iradix for the purposes of ordered iteration.
+	wildcardHostVolumes *iradix.Tree
+
 	agent    string
 	node     string
 	operator string
@@ -83,6 +90,8 @@ func NewACL(management bool, policies []*Policy) (*ACL, error) {
 	acl := &ACL{}
 	nsTxn := iradix.New().Txn()
 	wnsTxn := iradix.New().Txn()
+	hvTxn := iradix.New().Txn()
+	whvTxn := iradix.New().Txn()
 
 	for _, policy := range policies {
 	NAMESPACES:
@@ -128,6 +137,49 @@ func NewACL(management bool, policies []*Policy) (*ACL, error) {
 			}
 		}
 
+	HOSTVOLUMES:
+		for _, hv := range policy.HostVolumes {
+			// Should the volume be matched using a glob?
+			globDefinition := strings.Contains(hv.Name, "*")
+
+			// Check for existing capabilities
+			var capabilities capabilitySet
+
+			if globDefinition {
+				raw, ok := whvTxn.Get([]byte(hv.Name))
+				if ok {
+					capabilities = raw.(capabilitySet)
+				} else {
+					capabilities = make(capabilitySet)
+					whvTxn.Insert([]byte(hv.Name), capabilities)
+				}
+			} else {
+				raw, ok := hvTxn.Get([]byte(hv.Name))
+				if ok {
+					capabilities = raw.(capabilitySet)
+				} else {
+					capabilities = make(capabilitySet)
+					hvTxn.Insert([]byte(hv.Name), capabilities)
+				}
+			}
+
+			// Deny always takes precedence
+			if capabilities.Check(HostVolumeCapabilityDeny) {
+				continue
+			}
+
+			// Add in all the capabilities
+			for _, cap := range hv.Capabilities {
+				if cap == HostVolumeCapabilityDeny {
+					// Overwrite any existing capabilities
+					capabilities.Clear()
+					capabilities.Set(HostVolumeCapabilityDeny)
+					continue HOSTVOLUMES
+				}
+				capabilities.Set(cap)
+			}
+		}
+
 		// Take the maximum privilege for agent, node, and operator
 		if policy.Agent != nil {
 			acl.agent = maxPrivilege(acl.agent, policy.Agent.Policy)
@@ -146,6 +198,9 @@ func NewACL(management bool, policies []*Policy) (*ACL, error) {
 	// Finalize the namespaces
 	acl.namespaces = nsTxn.Commit()
 	acl.wildcardNamespaces = wnsTxn.Commit()
+	acl.hostVolumes = hvTxn.Commit()
+	acl.wildcardHostVolumes = whvTxn.Commit()
+
 	return acl, nil
 }
 
@@ -162,7 +217,7 @@ func (a *ACL) AllowNamespaceOperation(ns string, op string) bool {
 	}
 
 	// Check for a matching capability set
-	capabilities, ok := a.matchingCapabilitySet(ns)
+	capabilities, ok := a.matchingNamespaceCapabilitySet(ns)
 	if !ok {
 		return false
 	}
@@ -179,7 +234,45 @@ func (a *ACL) AllowNamespace(ns string) bool {
 	}
 
 	// Check for a matching capability set
-	capabilities, ok := a.matchingCapabilitySet(ns)
+	capabilities, ok := a.matchingNamespaceCapabilitySet(ns)
+	if !ok {
+		return false
+	}
+
+	// Check if the capability has been granted
+	if len(capabilities) == 0 {
+		return false
+	}
+
+	return !capabilities.Check(PolicyDeny)
+}
+
+// AllowHostVolumeOperation checks if a given operation is allowed for a host volume
+func (a *ACL) AllowHostVolumeOperation(hv string, op string) bool {
+	// Hot path management tokens
+	if a.management {
+		return true
+	}
+
+	// Check for a matching capability set
+	capabilities, ok := a.matchingHostVolumeCapabilitySet(hv)
+	if !ok {
+		return false
+	}
+
+	// Check if the capability has been granted
+	return capabilities.Check(op)
+}
+
+// AllowHostVolume checks if any operations are allowed for a HostVolume
+func (a *ACL) AllowHostVolume(ns string) bool {
+	// Hot path management tokens
+	if a.management {
+		return true
+	}
+
+	// Check for a matching capability set
+	capabilities, ok := a.matchingHostVolumeCapabilitySet(ns)
 	if !ok {
 		return false
 	}
@@ -192,31 +285,47 @@ func (a *ACL) AllowNamespace(ns string) bool {
 	return !capabilities.Check(PolicyDeny)
 }
 
-// matchingCapabilitySet looks for a capabilitySet that matches the namespace,
+// matchingNamespaceCapabilitySet looks for a capabilitySet that matches the namespace,
 // if no concrete definitions are found, then we return the closest matching
 // glob.
 // The closest matching glob is the one that has the smallest character
 // difference between the namespace and the glob.
-func (a *ACL) matchingCapabilitySet(ns string) (capabilitySet, bool) {
+func (a *ACL) matchingNamespaceCapabilitySet(ns string) (capabilitySet, bool) {
 	// Check for a concrete matching capability set
 	raw, ok := a.namespaces.Get([]byte(ns))
 	if ok {
 		return raw.(capabilitySet), true
 	}
 
 	// We didn't find a concrete match, so lets try and evaluate globs.
-	return a.findClosestMatchingGlob(ns)
+	return a.findClosestMatchingGlob(a.wildcardNamespaces, ns)
+}
+
+// matchingHostVolumeCapabilitySet looks for a capabilitySet that matches the host volume name,
+// if no concrete definitions are found, then we return the closest matching
+// glob.
+// The closest matching glob is the one that has the smallest character
+// difference between the volume name and the glob.
+func (a *ACL) matchingHostVolumeCapabilitySet(name string) (capabilitySet, bool) {
+	// Check for a concrete matching capability set
+	raw, ok := a.hostVolumes.Get([]byte(name))
+	if ok {
+		return raw.(capabilitySet), true
+	}
+
+	// We didn't find a concrete match, so lets try and evaluate globs.
+	return a.findClosestMatchingGlob(a.wildcardHostVolumes, name)
 }
 
 type matchingGlob struct {
-	ns            string
+	name          string
 	difference    int
 	capabilitySet capabilitySet
 }
 
-func (a *ACL) findClosestMatchingGlob(ns string) (capabilitySet, bool) {
+func (a *ACL) findClosestMatchingGlob(radix *iradix.Tree, ns string) (capabilitySet, bool) {
 	// First, find all globs that match.
-	matchingGlobs := a.findAllMatchingWildcards(ns)
+	matchingGlobs := findAllMatchingWildcards(radix, ns)
 
 	// If none match, let's return.
 	if len(matchingGlobs) == 0 {
@@ -238,19 +347,19 @@ func (a *ACL) findClosestMatchingGlob(ns string) (capabilitySet, bool) {
 	return matchingGlobs[0].capabilitySet, true
 }
 
-func (a *ACL) findAllMatchingWildcards(ns string) []matchingGlob {
+func findAllMatchingWildcards(radix *iradix.Tree, name string) []matchingGlob {
 	var matches []matchingGlob
 
-	nsLen := len(ns)
+	nsLen := len(name)
 
-	a.wildcardNamespaces.Root().Walk(func(bk []byte, iv interface{}) bool {
+	radix.Root().Walk(func(bk []byte, iv interface{}) bool {
 		k := string(bk)
 		v := iv.(capabilitySet)
 
-		isMatch := glob.Glob(k, ns)
+		isMatch := glob.Glob(k, name)
 		if isMatch {
 			pair := matchingGlob{
-				ns:            k,
+				name:          k,
 				difference:    nsLen - len(k) + strings.Count(k, glob.GLOB),
 				capabilitySet: v,
 			}

acl/acl_test.go

@@ -314,6 +314,56 @@ func TestWildcardNamespaceMatching(t *testing.T) {
 	}
 }
 
+func TestWildcardHostVolumeMatching(t *testing.T) {
+	tests := []struct {
+		Policy string
+		Allow  bool
+	}{
+		{ // Wildcard matches
+			Policy: `host_volume "prod-api-*" { policy = "write" }`,
+			Allow:  true,
+		},
+		{ // Non globbed volumes are not wildcards
+			Policy: `host_volume "prod-api" { policy = "write" }`,
+			Allow:  false,
+		},
+		{ // Concrete matches take precedence
+			Policy: `host_volume "prod-api-services" { policy = "deny" }
+			         host_volume "prod-api-*" { policy = "write" }`,
+			Allow: false,
+		},
+		{
+			Policy: `host_volume "prod-api-*" { policy = "deny" }
+			         host_volume "prod-api-services" { policy = "write" }`,
+			Allow: true,
+		},
+		{ // The closest character match wins
+			Policy: `host_volume "*-api-services" { policy = "deny" }
+			         host_volume "prod-api-*" { policy = "write" }`, // 4 vs 8 chars
+			Allow: false,
+		},
+		{
+			Policy: `host_volume "prod-api-*" { policy = "write" }
+               host_volume "*-api-services" { policy = "deny" }`, // 4 vs 8 chars
+			Allow: false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.Policy, func(t *testing.T) {
+			assert := assert.New(t)
+
+			policy, err := Parse(tc.Policy)
+			assert.NoError(err)
+			assert.NotNil(policy.HostVolumes)
+
+			acl, err := NewACL(false, []*Policy{policy})
+			assert.Nil(err)
+
+			assert.Equal(tc.Allow, acl.AllowHostVolume("prod-api-services"))
+		})
+	}
+}
 func TestACL_matchingCapabilitySet_returnsAllMatches(t *testing.T) {
 	tests := []struct {
 		Policy        string
@@ -351,8 +401,8 @@ func TestACL_matchingCapabilitySet_returnsAllMatches(t *testing.T) {
 			assert.Nil(err)
 
 			var namespaces []string
-			for _, cs := range acl.findAllMatchingWildcards(tc.NS) {
-				namespaces = append(namespaces, cs.ns)
+			for _, cs := range findAllMatchingWildcards(acl.wildcardNamespaces, tc.NS) {
+				namespaces = append(namespaces, cs.name)
 			}
 
 			assert.Equal(tc.MatchingGlobs, namespaces)
@@ -404,7 +454,7 @@ func TestACL_matchingCapabilitySet_difference(t *testing.T) {
 			acl, err := NewACL(false, []*Policy{policy})
 			assert.Nil(err)
 
-			matches := acl.findAllMatchingWildcards(tc.NS)
+			matches := findAllMatchingWildcards(acl.wildcardNamespaces, tc.NS)
 			assert.Equal(tc.Difference, matches[0].difference)
 		})
 	}