forked from hashicorp/vault
/
validation.go
424 lines (365 loc) · 14.4 KB
/
validation.go
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package approle
import (
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"fmt"
"net"
"strings"
"sync"
"time"
"github.com/hashicorp/go-uuid"
"github.com/hashicorp/vault/logical"
"github.com/hashicorp/vault/logical/framework"
)
// secretIDStorageEntry represents the information stored in storage
// when a SecretID is created. The structure of the SecretID storage
// entry is the same for all the types of SecretIDs generated.
type secretIDStorageEntry struct {
// Accessor for the SecretID. It is a random UUID serving as
// a secondary index for the SecretID. This uniquely identifies
// the SecretID it belongs to, and hence can be used for listing
// and deleting SecretIDs. Accessors cannot be used as valid
// SecretIDs during login.
SecretIDAccessor string `json:"secret_id_accessor" structs:"secret_id_accessor" mapstructure:"secret_id_accessor"`
// Number of times this SecretID can be used to perform the login operation
SecretIDNumUses int `json:"secret_id_num_uses" structs:"secret_id_num_uses" mapstructure:"secret_id_num_uses"`
// Duration after which this SecretID should expire. This is
// croleed by the backend mount's max TTL value.
SecretIDTTL time.Duration `json:"secret_id_ttl" structs:"secret_id_ttl" mapstructure:"secret_id_ttl"`
// The time when the SecretID was created
CreationTime time.Time `json:"creation_time" structs:"creation_time" mapstructure:"creation_time"`
// The time when the SecretID becomes eligible for tidy
// operation. Tidying is performed by the PeriodicFunc of the
// backend which is 1 minute apart.
ExpirationTime time.Time `json:"expiration_time" structs:"expiration_time" mapstructure:"expiration_time"`
// The time representing the last time this storage entry was modified
LastUpdatedTime time.Time `json:"last_updated_time" structs:"last_updated_time" mapstructure:"last_updated_time"`
// Metadata that belongs to the SecretID.
Metadata map[string]string `json:"metadata" structs:"metadata" mapstructure:"metadata"`
}
// Represents the payload of the storage entry of the accessor that maps to a unique
// SecretID. Note that SecretIDs should never be stored in plaintext anywhere in the
// backend. SecretIDHMAC will be used as an index to fetch the properties of the
// SecretID and to delete the SecretID.
type secretIDAccessorStorageEntry struct {
// Hash of the SecretID which can be used to find the storage index at which
// properties of SecretID is stored.
SecretIDHMAC string `json:"secret_id_hmac" structs:"secret_id_hmac" mapstructure:"secret_id_hmac"`
}
// Checks if all the CIDR blocks in the comma separated list are valid by parsing it.
func validateCIDRList(cidrList string) error {
if cidrList == "" {
return nil
}
cidrBlocks := strings.Split(cidrList, ",")
for _, block := range cidrBlocks {
if _, _, err := net.ParseCIDR(strings.TrimSpace(block)); err != nil {
return err
}
}
return nil
}
// Checks if the Role represented by the RoleID still exists
func (b *backend) validateRoleID(s logical.Storage, roleID string) (*roleStorageEntry, string, error) {
// Look for the storage entry that maps the roleID to role
roleIDIndex, err := b.roleIDEntry(s, roleID)
if err != nil {
return nil, "", err
}
if roleIDIndex == nil {
return nil, "", fmt.Errorf("failed to find secondary index for role_id:%s\n", roleID)
}
role, err := b.roleEntry(s, roleIDIndex.Name)
if err != nil {
return nil, "", err
}
if role == nil {
return nil, "", fmt.Errorf("role %s referred by the SecretID does not exist", roleIDIndex.Name)
}
return role, roleIDIndex.Name, nil
}
// Validates the supplied RoleID and SecretID
func (b *backend) validateCredentials(req *logical.Request, data *framework.FieldData) (*roleStorageEntry, string, map[string]string, error) {
var metadata map[string]string
// RoleID must be supplied during every login
roleID := strings.TrimSpace(data.Get("role_id").(string))
if roleID == "" {
return nil, "", metadata, fmt.Errorf("missing role_id")
}
// Validate the RoleID and get the Role entry
role, roleName, err := b.validateRoleID(req.Storage, roleID)
if err != nil {
return nil, "", metadata, err
}
if role == nil || roleName == "" {
return nil, "", metadata, fmt.Errorf("failed to validate role_id")
}
// Calculate the TTL boundaries since this reflects the properties of the token issued
if role.TokenTTL, role.TokenMaxTTL, err = b.SanitizeTTL(role.TokenTTL, role.TokenMaxTTL); err != nil {
return nil, "", metadata, err
}
if role.BindSecretID {
// If 'bind_secret_id' was set on role, look for the field 'secret_id'
// to be specified and validate it.
secretID := strings.TrimSpace(data.Get("secret_id").(string))
if secretID == "" {
return nil, "", metadata, fmt.Errorf("missing secret_id")
}
// Check if the SecretID supplied is valid. If use limit was specified
// on the SecretID, it will be decremented in this call.
var valid bool
valid, metadata, err = b.validateBindSecretID(req.Storage, roleName, secretID, role.HMACKey)
if err != nil {
return nil, "", metadata, err
}
if !valid {
return nil, "", metadata, fmt.Errorf("invalid secret_id: %s\n", secretID)
}
}
if role.BoundCIDRList != "" {
// If 'bound_cidr_list' was set, verify the CIDR restrictions
cidrBlocks := strings.Split(role.BoundCIDRList, ",")
for _, block := range cidrBlocks {
_, cidr, err := net.ParseCIDR(block)
if err != nil {
return nil, "", metadata, fmt.Errorf("invalid cidr: %s", err)
}
var addr string
if req.Connection != nil {
addr = req.Connection.RemoteAddr
}
if addr == "" || !cidr.Contains(net.ParseIP(addr)) {
return nil, "", metadata, fmt.Errorf("unauthorized source address")
}
}
}
return role, roleName, metadata, nil
}
// validateBindSecretID is used to determine if the given SecretID is a valid one.
func (b *backend) validateBindSecretID(s logical.Storage, roleName, secretID, hmacKey string) (bool, map[string]string, error) {
secretIDHMAC, err := createHMAC(hmacKey, secretID)
if err != nil {
return false, nil, fmt.Errorf("failed to create HMAC of secret_id: %s", err)
}
roleNameHMAC, err := createHMAC(hmacKey, roleName)
if err != nil {
return false, nil, fmt.Errorf("failed to create HMAC of role_name: %s", err)
}
entryIndex := fmt.Sprintf("secret_id/%s/%s", roleNameHMAC, secretIDHMAC)
// SecretID locks are always index based on secretIDHMACs. This helps
// acquiring the locks when the SecretIDs are listed. This allows grabbing
// the correct locks even if the SecretIDs are not known in plaintext.
lock := b.secretIDLock(secretIDHMAC)
lock.RLock()
result := secretIDStorageEntry{}
if entry, err := s.Get(entryIndex); err != nil {
lock.RUnlock()
return false, nil, err
} else if entry == nil {
lock.RUnlock()
return false, nil, nil
} else if err := entry.DecodeJSON(&result); err != nil {
lock.RUnlock()
return false, nil, err
}
// SecretIDNumUses will be zero only if the usage limit was not set at all,
// in which case, the SecretID will remain to be valid as long as it is not
// expired.
if result.SecretIDNumUses == 0 {
lock.RUnlock()
return true, result.Metadata, nil
}
// If the SecretIDNumUses is non-zero, it means that its use-count should be updated
// in the storage. Switch the lock from a `read` to a `write` and update
// the storage entry.
lock.RUnlock()
lock.Lock()
defer lock.Unlock()
// Lock switching may change the data. Refresh the contents.
result = secretIDStorageEntry{}
if entry, err := s.Get(entryIndex); err != nil {
return false, nil, err
} else if entry == nil {
return false, nil, nil
} else if err := entry.DecodeJSON(&result); err != nil {
return false, nil, err
}
// If there exists a single use left, delete the SecretID entry from
// the storage but do not fail the validation request. Subsequest
// requests to use the same SecretID will fail.
if result.SecretIDNumUses == 1 {
accessorEntryIndex := "accessor/" + b.salt.SaltID(result.SecretIDAccessor)
if err := s.Delete(accessorEntryIndex); err != nil {
return false, nil, fmt.Errorf("failed to delete accessor storage entry: %s", err)
}
if err := s.Delete(entryIndex); err != nil {
return false, nil, fmt.Errorf("failed to delete SecretID: %s", err)
}
} else {
// If the use count is greater than one, decrement it and update the last updated time.
result.SecretIDNumUses -= 1
result.LastUpdatedTime = time.Now()
if entry, err := logical.StorageEntryJSON(entryIndex, &result); err != nil {
return false, nil, fmt.Errorf("failed to decrement the use count for SecretID:%s", secretID)
} else if err = s.Put(entry); err != nil {
return false, nil, fmt.Errorf("failed to decrement the use count for SecretID:%s", secretID)
}
}
return true, result.Metadata, nil
}
// Creates a SHA256 HMAC of the given 'value' using the given 'key'
// and returns a hex encoded string.
func createHMAC(key, value string) (string, error) {
if key == "" {
return "", fmt.Errorf("invalid HMAC key")
}
hm := hmac.New(sha256.New, []byte(key))
hm.Write([]byte(value))
return hex.EncodeToString(hm.Sum(nil)), nil
}
// secretIDLock is used to get a lock from the pre-initialized map
// of locks. Map is indexed based on the first 2 characters of the
// secretIDHMAC. If the input is not hex encoded or if empty, a
// "custom" lock will be returned.
func (b *backend) secretIDLock(secretIDHMAC string) *sync.RWMutex {
var lock *sync.RWMutex
var ok bool
if len(secretIDHMAC) >= 2 {
lock, ok = b.secretIDLocksMap[secretIDHMAC[0:2]]
}
if !ok || lock == nil {
// Fall back for custom SecretIDs
lock = b.secretIDLocksMap["custom"]
}
return lock
}
// registerSecretIDEntry creates a new storage entry for the given SecretID.
func (b *backend) registerSecretIDEntry(s logical.Storage, roleName, secretID, hmacKey string, secretEntry *secretIDStorageEntry) (*secretIDStorageEntry, error) {
secretIDHMAC, err := createHMAC(hmacKey, secretID)
if err != nil {
return nil, fmt.Errorf("failed to create HMAC of secret_id: %s", err)
}
roleNameHMAC, err := createHMAC(hmacKey, roleName)
if err != nil {
return nil, fmt.Errorf("failed to create HMAC of role_name: %s", err)
}
entryIndex := fmt.Sprintf("secret_id/%s/%s", roleNameHMAC, secretIDHMAC)
lock := b.secretIDLock(secretIDHMAC)
lock.RLock()
entry, err := s.Get(entryIndex)
if err != nil {
lock.RUnlock()
return nil, err
}
if entry != nil {
lock.RUnlock()
return nil, fmt.Errorf("SecretID is already registered")
}
// If there isn't an entry for the secretID already, switch the read lock
// with a write lock and create an entry.
lock.RUnlock()
lock.Lock()
defer lock.Unlock()
// But before saving a new entry, check if the secretID entry was created during the lock switch.
entry, err = s.Get(entryIndex)
if err != nil {
return nil, err
}
if entry != nil {
return nil, fmt.Errorf("SecretID is already registered")
}
// Create a new entry for the SecretID
// Set the creation time for the SecretID
currentTime := time.Now()
secretEntry.CreationTime = currentTime
secretEntry.LastUpdatedTime = currentTime
// If SecretIDTTL is not specified or if it crosses the backend mount's limit,
// cap the expiration to backend's max. Otherwise, use it to determine the
// expiration time.
if secretEntry.SecretIDTTL < time.Duration(0) || secretEntry.SecretIDTTL > b.System().MaxLeaseTTL() {
secretEntry.ExpirationTime = currentTime.Add(b.System().MaxLeaseTTL())
} else if secretEntry.SecretIDTTL != time.Duration(0) {
// Set the ExpirationTime only if SecretIDTTL was set. SecretIDs should not
// expire by default.
secretEntry.ExpirationTime = currentTime.Add(secretEntry.SecretIDTTL)
}
// Before storing the SecretID, store its accessor.
if err := b.createAccessor(s, secretEntry, secretIDHMAC); err != nil {
return nil, err
}
if entry, err := logical.StorageEntryJSON(entryIndex, secretEntry); err != nil {
return nil, err
} else if err = s.Put(entry); err != nil {
return nil, err
}
return secretEntry, nil
}
// secretIDAccessorEntry is used to read the storage entry that maps an
// accessor to a secret_id. This method should be called when the lock
// for the corresponding SecretID is held.
func (b *backend) secretIDAccessorEntry(s logical.Storage, secretIDAccessor string) (*secretIDAccessorStorageEntry, error) {
if secretIDAccessor == "" {
return nil, fmt.Errorf("missing secretIDAccessor")
}
var result secretIDAccessorStorageEntry
// Create index entry, mapping the accessor to the token ID
entryIndex := "accessor/" + b.salt.SaltID(secretIDAccessor)
if entry, err := s.Get(entryIndex); err != nil {
return nil, err
} else if entry == nil {
return nil, nil
} else if err := entry.DecodeJSON(&result); err != nil {
return nil, err
}
return &result, nil
}
// createAccessor creates an identifier for the SecretID. A storage index,
// mapping the accessor to the SecretID is also created. This method should
// be called when the lock for the corresponding SecretID is held.
func (b *backend) createAccessor(s logical.Storage, entry *secretIDStorageEntry, secretIDHMAC string) error {
// Create a random accessor
accessorUUID, err := uuid.GenerateUUID()
if err != nil {
return err
}
entry.SecretIDAccessor = accessorUUID
// Create index entry, mapping the accessor to the token ID
entryIndex := "accessor/" + b.salt.SaltID(entry.SecretIDAccessor)
if entry, err := logical.StorageEntryJSON(entryIndex, &secretIDAccessorStorageEntry{
SecretIDHMAC: secretIDHMAC,
}); err != nil {
return err
} else if err = s.Put(entry); err != nil {
return fmt.Errorf("failed to persist accessor index entry: %s", err)
}
return nil
}
// flushRoleSecrets deletes all the SecretIDs that belong to the given
// RoleID.
func (b *backend) flushRoleSecrets(s logical.Storage, roleName, hmacKey string) error {
roleNameHMAC, err := createHMAC(hmacKey, roleName)
if err != nil {
return fmt.Errorf("failed to create HMAC of role_name: %s", err)
}
// Acquire the custom lock to perform listing of SecretIDs
customLock := b.secretIDLock("")
customLock.RLock()
defer customLock.RUnlock()
secretIDHMACs, err := s.List(fmt.Sprintf("secret_id/%s/", roleNameHMAC))
if err != nil {
return err
}
for _, secretIDHMAC := range secretIDHMACs {
// Acquire the lock belonging to the SecretID
lock := b.secretIDLock(secretIDHMAC)
lock.Lock()
entryIndex := fmt.Sprintf("secret_id/%s/%s", roleNameHMAC, secretIDHMAC)
if err := s.Delete(entryIndex); err != nil {
lock.Unlock()
return fmt.Errorf("error deleting SecretID %s from storage: %s", secretIDHMAC, err)
}
lock.Unlock()
}
return nil
}