open-vault/builtin/logical/transit/path_encrypt.go
Jeff Mitchell 76b0d11793
Redo transit locking (#4720)
This massively simplifies transit locking behavior by pushing some
locking down to the Policy level, and embedding either a local or global
lock in the Policy depending on whether caching is enabled or not.
2018-06-12 12:24:12 -04:00

315 lines
9.9 KiB
Go

package transit
import (
"context"
"encoding/base64"
"fmt"
"github.com/hashicorp/errwrap"
"github.com/hashicorp/vault/helper/errutil"
"github.com/hashicorp/vault/helper/keysutil"
"github.com/hashicorp/vault/logical"
"github.com/hashicorp/vault/logical/framework"
"github.com/mitchellh/mapstructure"
)
// BatchRequestItem represents a request item for batch processing
type BatchRequestItem struct {
// Context for key derivation. This is required for derived keys.
Context string `json:"context" structs:"context" mapstructure:"context"`
// DecodedContext is the base64 decoded version of Context
DecodedContext []byte
// Plaintext for encryption
Plaintext string `json:"plaintext" structs:"plaintext" mapstructure:"plaintext"`
// Ciphertext for decryption
Ciphertext string `json:"ciphertext" structs:"ciphertext" mapstructure:"ciphertext"`
// Nonce to be used when v1 convergent encryption is used
Nonce string `json:"nonce" structs:"nonce" mapstructure:"nonce"`
// The key version to be used for encryption
KeyVersion int `json:"key_version" structs:"key_version" mapstructure:"key_version"`
// DecodedNonce is the base64 decoded version of Nonce
DecodedNonce []byte
}
// BatchResponseItem represents a response item for batch processing
type BatchResponseItem struct {
// Ciphertext for the plaintext present in the corresponding batch
// request item
Ciphertext string `json:"ciphertext,omitempty" structs:"ciphertext" mapstructure:"ciphertext"`
// Plaintext for the ciphertext present in the corresponding batch
// request item
Plaintext string `json:"plaintext,omitempty" structs:"plaintext" mapstructure:"plaintext"`
// Error, if set represents a failure encountered while encrypting a
// corresponding batch request item
Error string `json:"error,omitempty" structs:"error" mapstructure:"error"`
}
func (b *backend) pathEncrypt() *framework.Path {
return &framework.Path{
Pattern: "encrypt/" + framework.GenericNameRegex("name"),
Fields: map[string]*framework.FieldSchema{
"name": &framework.FieldSchema{
Type: framework.TypeString,
Description: "Name of the policy",
},
"plaintext": &framework.FieldSchema{
Type: framework.TypeString,
Description: "Base64 encoded plaintext value to be encrypted",
},
"context": &framework.FieldSchema{
Type: framework.TypeString,
Description: "Base64 encoded context for key derivation. Required if key derivation is enabled",
},
"nonce": &framework.FieldSchema{
Type: framework.TypeString,
Description: `
Base64 encoded nonce value. Must be provided if convergent encryption is
enabled for this key and the key was generated with Vault 0.6.1. Not required
for keys created in 0.6.2+. The value must be exactly 96 bits (12 bytes) long
and the user must ensure that for any given context (and thus, any given
encryption key) this nonce value is **never reused**.
`,
},
"type": &framework.FieldSchema{
Type: framework.TypeString,
Default: "aes256-gcm96",
Description: `
This parameter is required when encryption key is expected to be created.
When performing an upsert operation, the type of key to create. Currently,
"aes256-gcm96" (symmetric) is the only type supported. Defaults to
"aes256-gcm96".`,
},
"convergent_encryption": &framework.FieldSchema{
Type: framework.TypeBool,
Description: `
This parameter will only be used when a key is expected to be created. Whether
to support convergent encryption. This is only supported when using a key with
key derivation enabled and will require all requests to carry both a context
and 96-bit (12-byte) nonce. The given nonce will be used in place of a randomly
generated nonce. As a result, when the same context and nonce are supplied, the
same ciphertext is generated. It is *very important* when using this mode that
you ensure that all nonces are unique for a given context. Failing to do so
will severely impact the ciphertext's security.`,
},
"key_version": &framework.FieldSchema{
Type: framework.TypeInt,
Description: `The version of the key to use for encryption.
Must be 0 (for latest) or a value greater than or equal
to the min_encryption_version configured on the key.`,
},
},
Callbacks: map[logical.Operation]framework.OperationFunc{
logical.CreateOperation: b.pathEncryptWrite,
logical.UpdateOperation: b.pathEncryptWrite,
},
ExistenceCheck: b.pathEncryptExistenceCheck,
HelpSynopsis: pathEncryptHelpSyn,
HelpDescription: pathEncryptHelpDesc,
}
}
func (b *backend) pathEncryptExistenceCheck(ctx context.Context, req *logical.Request, d *framework.FieldData) (bool, error) {
name := d.Get("name").(string)
p, _, err := b.lm.GetPolicy(ctx, keysutil.PolicyRequest{
Storage: req.Storage,
Name: name,
})
if err != nil {
return false, err
}
if p != nil && b.System().CachingDisabled() {
p.Unlock()
}
return p != nil, nil
}
func (b *backend) pathEncryptWrite(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
name := d.Get("name").(string)
var err error
batchInputRaw := d.Raw["batch_input"]
var batchInputItems []BatchRequestItem
if batchInputRaw != nil {
err = mapstructure.Decode(batchInputRaw, &batchInputItems)
if err != nil {
return nil, errwrap.Wrapf("failed to parse batch input: {{err}}", err)
}
if len(batchInputItems) == 0 {
return logical.ErrorResponse("missing batch input to process"), logical.ErrInvalidRequest
}
} else {
valueRaw, ok := d.GetOk("plaintext")
if !ok {
return logical.ErrorResponse("missing plaintext to encrypt"), logical.ErrInvalidRequest
}
batchInputItems = make([]BatchRequestItem, 1)
batchInputItems[0] = BatchRequestItem{
Plaintext: valueRaw.(string),
Context: d.Get("context").(string),
Nonce: d.Get("nonce").(string),
KeyVersion: d.Get("key_version").(int),
}
}
batchResponseItems := make([]BatchResponseItem, len(batchInputItems))
contextSet := len(batchInputItems[0].Context) != 0
// Before processing the batch request items, get the policy. If the
// policy is supposed to be upserted, then determine if 'derived' is to
// be set or not, based on the presence of 'context' field in all the
// input items.
for i, item := range batchInputItems {
if (len(item.Context) == 0 && contextSet) || (len(item.Context) != 0 && !contextSet) {
return logical.ErrorResponse("context should be set either in all the request blocks or in none"), logical.ErrInvalidRequest
}
_, err := base64.StdEncoding.DecodeString(item.Plaintext)
if err != nil {
batchResponseItems[i].Error = err.Error()
continue
}
// Decode the context
if len(item.Context) != 0 {
batchInputItems[i].DecodedContext, err = base64.StdEncoding.DecodeString(item.Context)
if err != nil {
batchResponseItems[i].Error = err.Error()
continue
}
}
// Decode the nonce
if len(item.Nonce) != 0 {
batchInputItems[i].DecodedNonce, err = base64.StdEncoding.DecodeString(item.Nonce)
if err != nil {
batchResponseItems[i].Error = err.Error()
continue
}
}
}
// Get the policy
var p *keysutil.Policy
var upserted bool
var polReq keysutil.PolicyRequest
if req.Operation == logical.CreateOperation {
convergent := d.Get("convergent_encryption").(bool)
if convergent && !contextSet {
return logical.ErrorResponse("convergent encryption requires derivation to be enabled, so context is required"), nil
}
polReq = keysutil.PolicyRequest{
Upsert: true,
Storage: req.Storage,
Name: name,
Derived: contextSet,
Convergent: convergent,
}
keyType := d.Get("type").(string)
switch keyType {
case "aes256-gcm96":
polReq.KeyType = keysutil.KeyType_AES256_GCM96
case "chacha20-poly1305":
polReq.KeyType = keysutil.KeyType_ChaCha20_Poly1305
case "ecdsa-p256":
return logical.ErrorResponse(fmt.Sprintf("key type %v not supported for this operation", keyType)), logical.ErrInvalidRequest
default:
return logical.ErrorResponse(fmt.Sprintf("unknown key type %v", keyType)), logical.ErrInvalidRequest
}
} else {
polReq = keysutil.PolicyRequest{
Storage: req.Storage,
Name: name,
}
}
p, upserted, err = b.lm.GetPolicy(ctx, polReq)
if err != nil {
return nil, err
}
if p == nil {
return logical.ErrorResponse("encryption key not found"), logical.ErrInvalidRequest
}
if !b.System().CachingDisabled() {
p.Lock(false)
}
// Process batch request items. If encryption of any request
// item fails, respectively mark the error in the response
// collection and continue to process other items.
for i, item := range batchInputItems {
if batchResponseItems[i].Error != "" {
continue
}
ciphertext, err := p.Encrypt(item.KeyVersion, item.DecodedContext, item.DecodedNonce, item.Plaintext)
if err != nil {
switch err.(type) {
case errutil.UserError:
batchResponseItems[i].Error = err.Error()
continue
default:
p.Unlock()
return nil, err
}
}
if ciphertext == "" {
p.Unlock()
return nil, fmt.Errorf("empty ciphertext returned for input item %d", i)
}
batchResponseItems[i].Ciphertext = ciphertext
}
resp := &logical.Response{}
if batchInputRaw != nil {
resp.Data = map[string]interface{}{
"batch_results": batchResponseItems,
}
} else {
if batchResponseItems[0].Error != "" {
p.Unlock()
return logical.ErrorResponse(batchResponseItems[0].Error), logical.ErrInvalidRequest
}
resp.Data = map[string]interface{}{
"ciphertext": batchResponseItems[0].Ciphertext,
}
}
if req.Operation == logical.CreateOperation && !upserted {
resp.AddWarning("Attempted creation of the key during the encrypt operation, but it was created beforehand")
}
p.Unlock()
return resp, nil
}
const pathEncryptHelpSyn = `Encrypt a plaintext value or a batch of plaintext
blocks using a named key`
const pathEncryptHelpDesc = `
This path uses the named key from the request path to encrypt a user provided
plaintext or a batch of plaintext blocks. The plaintext must be base64 encoded.
`