support multiple policies for temporary users (#9550)

cmd/api-errors.go

@@ -1649,7 +1649,7 @@ func toAPIErrorCode(ctx context.Context, err error) (apiErr APIErrorCode) {
 	if err == nil {
 		return ErrNone
 	}
-	// Verify if the underlying error is signature mismatch.
+
 	switch err {
 	case errInvalidArgument:
 		apiErr = ErrAdminInvalidArgument

cmd/iam.go

@@ -22,6 +22,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	"github.com/minio/minio-go/v6/pkg/set"
 	"github.com/minio/minio/cmd/config"
@@ -166,6 +167,10 @@ type MappedPolicy struct {
 	Policy  string `json:"policy"`
 }
 
+func (mp MappedPolicy) policySet() set.StringSet {
+	return set.CreateStringSet(strings.Split(mp.Policy, ",")...)
+}
+
 func newMappedPolicy(policy string) MappedPolicy {
 	return MappedPolicy{Version: 1, Policy: policy}
 }
@@ -591,11 +596,26 @@ func (sys *IAMSys) SetTempUser(accessKey string, cred auth.Credentials, policyNa
 	// temporary user which match with pre-configured canned
 	// policies for this server.
 	if globalPolicyOPA == nil && policyName != "" {
-		p, ok := sys.iamPolicyDocsMap[policyName]
-		if !ok {
-			return errInvalidArgument
+		var availablePolicies []iampolicy.Policy
+		for _, pname := range strings.Split(policyName, ",") {
+			pname = strings.TrimSpace(pname)
+			if pname == "" {
+				continue
+			}
+			p, found := sys.iamPolicyDocsMap[pname]
+			if !found {
+				return fmt.Errorf("%w: (%s)", errNoSuchPolicy, pname)
+			}
+			availablePolicies = append(availablePolicies, p)
 		}
-		if p.IsEmpty() {
+
+		combinedPolicy := availablePolicies[0]
+		for i := 1; i < len(availablePolicies); i++ {
+			combinedPolicy.Statements = append(combinedPolicy.Statements,
+				availablePolicies[i].Statements...)
+		}
+
+		if combinedPolicy.IsEmpty() {
 			delete(sys.iamUserPolicyMap, accessKey)
 			return nil
 		}
@@ -1265,13 +1285,10 @@ func (sys *IAMSys) PolicyDBSet(name, policy string, isGroup bool) error {
 
 // policyDBSet - sets a policy for user in the policy db. Assumes that caller
 // has sys.Lock(). If policy == "", then policy mapping is removed.
-func (sys *IAMSys) policyDBSet(name, policy string, userType IAMUserType, isGroup bool) error {
+func (sys *IAMSys) policyDBSet(name, policyName string, userType IAMUserType, isGroup bool) error {
 	if name == "" {
 		return errInvalidArgument
 	}
-	if _, ok := sys.iamPolicyDocsMap[policy]; !ok && policy != "" {
-		return errNoSuchPolicy
-	}
 
 	if sys.usersSysType == MinIOUsersSysType {
 		if !isGroup {
@@ -1286,7 +1303,7 @@ func (sys *IAMSys) policyDBSet(name, policy string, userType IAMUserType, isGrou
 	}
 
 	// Handle policy mapping removal
-	if policy == "" {
+	if policyName == "" {
 		if err := sys.store.deleteMappedPolicy(name, userType, isGroup); err != nil && err != errNoSuchPolicy {
 			return err
 		}
@@ -1298,8 +1315,19 @@ func (sys *IAMSys) policyDBSet(name, policy string, userType IAMUserType, isGrou
 		return nil
 	}
 
+	for _, pname := range strings.Split(policyName, ",") {
+		pname = strings.TrimSpace(pname)
+		if pname == "" {
+			continue
+		}
+		if _, found := sys.iamPolicyDocsMap[pname]; !found {
+			logger.LogIf(GlobalContext, fmt.Errorf("%w: (%s)", errNoSuchPolicy, pname))
+			return errNoSuchPolicy
+		}
+	}
+
 	// Handle policy mapping set/update
-	mp := newMappedPolicy(policy)
+	mp := newMappedPolicy(policyName)
 	if err := sys.store.saveMappedPolicy(name, userType, isGroup, mp); err != nil {
 		return err
 	}
@@ -1644,14 +1672,15 @@ func (sys *IAMSys) IsAllowedSTS(args iampolicy.Args) bool {
 		return combinedPolicy.IsAllowed(args)
 	}
 
-	pnameSlice, ok := args.GetPolicies(iamPolicyClaimNameOpenID())
+	policies, ok := args.GetPolicies(iamPolicyClaimNameOpenID())
 	if !ok {
 		// When claims are set, it should have a policy claim field.
 		return false
 	}
 
-	// When claims are set, it should have a policy claim field.
-	if len(pnameSlice) == 0 {
+	// When claims are set, it should have policies as claim.
+	if policies.IsEmpty() {
+		// No policy, no access!
 		return false
 	}
 
@@ -1661,18 +1690,33 @@ func (sys *IAMSys) IsAllowedSTS(args iampolicy.Args) bool {
 	// If policy is available for given user, check the policy.
 	mp, ok := sys.iamUserPolicyMap[args.AccountName]
 	if !ok {
-		// No policy available reject.
+		// No policy set for the user that we can find, no access!
 		return false
 	}
-	name := mp.Policy
 
-	if pnameSlice[0] != name {
+	if !policies.Equals(mp.policySet()) {
 		// When claims has a policy, it should match the
 		// policy of args.AccountName which server remembers.
 		// if not reject such requests.
 		return false
 	}
 
+	var availablePolicies []iampolicy.Policy
+	for pname := range policies {
+		p, found := sys.iamPolicyDocsMap[pname]
+		if !found {
+			logger.LogIf(GlobalContext, fmt.Errorf("%w: (%s)", errNoSuchPolicy, pname))
+			return false
+		}
+		availablePolicies = append(availablePolicies, p)
+	}
+
+	combinedPolicy := availablePolicies[0]
+	for i := 1; i < len(availablePolicies); i++ {
+		combinedPolicy.Statements = append(combinedPolicy.Statements,
+			availablePolicies[i].Statements...)
+	}
+
 	// Now check if we have a sessionPolicy.
 	spolicy, ok := args.Claims[iampolicy.SessionPolicyName]
 	if ok {
@@ -1697,14 +1741,12 @@ func (sys *IAMSys) IsAllowedSTS(args iampolicy.Args) bool {
 		}
 
 		// Sub policy is set and valid.
-		p, ok := sys.iamPolicyDocsMap[pnameSlice[0]]
-		return ok && p.IsAllowed(args) && subPolicy.IsAllowed(args)
+		return combinedPolicy.IsAllowed(args) && subPolicy.IsAllowed(args)
 	}
 
 	// Sub policy not set, this is most common since subPolicy
-	// is optional, use the top level policy only.
-	p, ok := sys.iamPolicyDocsMap[pnameSlice[0]]
-	return ok && p.IsAllowed(args)
+	// is optional, use the inherited policies.
+	return combinedPolicy.IsAllowed(args)
 }
 
 // IsAllowed - checks given policy args is allowed to continue the Rest API.

pkg/iam/policy/policy.go

@@ -21,6 +21,7 @@ import (
 	"io"
 	"strings"
 
+	"github.com/minio/minio-go/v6/pkg/set"
 	"github.com/minio/minio/pkg/bucket/policy"
 )
 
@@ -39,17 +40,31 @@ type Args struct {
 }
 
 // GetPolicies get policies
-func (a Args) GetPolicies(policyClaimName string) ([]string, bool) {
+func (a Args) GetPolicies(policyClaimName string) (set.StringSet, bool) {
+	s := set.NewStringSet()
 	pname, ok := a.Claims[policyClaimName]
 	if !ok {
-		return nil, false
+		return s, false
 	}
-	pnameStr, ok := pname.(string)
-	if ok {
-		return strings.Split(pnameStr, ","), true
+	pnames, ok := pname.([]string)
+	if !ok {
+		pnameStr, ok := pname.(string)
+		if ok {
+			pnames = strings.Split(pnameStr, ",")
+		} else {
+			return s, false
+		}
 	}
-	pnameSlice, ok := pname.([]string)
-	return pnameSlice, ok
+	for _, pname := range pnames {
+		pname = strings.TrimSpace(pname)
+		if pname == "" {
+			// ignore any empty strings, considerate
+			// towards some user errors.
+			continue
+		}
+		s.Add(pname)
+	}
+	return s, true
 }
 
 // Policy - iam bucket iamp.