content-length-range policy should be honored for the uploaded object sizes. (#3076)

cmd/bucket-handlers.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"encoding/base64"
 	"encoding/xml"
 	"io"
 	"net/http"
@@ -450,11 +451,35 @@ func (api objectAPIHandlers) PostPolicyBucketHandler(w http.ResponseWriter, r *h
 		writeErrorResponse(w, r, apiErr, r.URL.Path)
 		return
 	}
-	if apiErr = checkPostPolicy(formValues); apiErr != ErrNone {
+
+	policyBytes, err := base64.StdEncoding.DecodeString(formValues["Policy"])
+	if err != nil {
+		writeErrorResponse(w, r, ErrMalformedPOSTRequest, r.URL.Path)
+		return
+	}
+
+	postPolicyForm, err := parsePostPolicyFormV4(string(policyBytes))
+	if err != nil {
+		writeErrorResponse(w, r, ErrMalformedPOSTRequest, r.URL.Path)
+		return
+	}
+
+	// Make sure formValues adhere to policy restrictions.
+	if apiErr = checkPostPolicy(formValues, postPolicyForm); apiErr != ErrNone {
 		writeErrorResponse(w, r, apiErr, r.URL.Path)
 		return
 	}
 
+	// Use limitReader to ensure that object size is within expected range.
+	lengthRange := postPolicyForm.Conditions.ContentLengthRange
+	if lengthRange.Valid {
+		// If policy restricted the size of the object.
+		fileBody = limitReader(fileBody, int64(lengthRange.Min), int64(lengthRange.Max))
+	} else {
+		// Default values of min/max size of the object.
+		fileBody = limitReader(fileBody, 0, maxObjectSize)
+	}
+
 	// Save metadata.
 	metadata := make(map[string]string)
 	// Nothing to store right now.

cmd/handler-utils.go

@@ -114,7 +114,7 @@ func extractPostPolicyFormValues(reader *multipart.Reader) (filePart io.Reader,
 				}
 				formValues[canonicalFormName] = string(buffer)
 			} else {
-				filePart = limitReader(part, maxObjectSize)
+				filePart = part
 				fileName = part.FileName()
 				// As described in S3 spec, we expect file to be the last form field
 				break

cmd/object-errors.go

@@ -81,6 +81,13 @@ func toObjectErr(err error, params ...string) error {
 				Object: params[1],
 			}
 		}
+	case errDataTooSmall:
+		if len(params) >= 2 {
+			err = ObjectTooSmall{
+				Bucket: params[0],
+				Object: params[1],
+			}
+		}
 	case errXLReadQuorum:
 		err = InsufficientReadQuorum{}
 	case errXLWriteQuorum:
@@ -266,6 +273,13 @@ func (e ObjectTooLarge) Error() string {
 	return "size of the object greater than what is allowed(5G)"
 }
 
+// ObjectTooSmall error returned when the size of the object < what is expected.
+type ObjectTooSmall GenericError
+
+func (e ObjectTooSmall) Error() string {
+	return "size of the object less than what is expected"
+}
+
 /// Multipart related errors.
 
 // MalformedUploadID malformed upload id.

cmd/object-utils.go

@@ -169,17 +169,22 @@ func (d byBucketName) Less(i, j int) bool { return d[i].Name < d[j].Name }
 // The underlying implementation is a *LimitedReader.
 type limitedReader struct {
 	R io.Reader // underlying reader
+	M int64     // min bytes remaining
 	N int64     // max bytes remaining
 }
 
-func limitReader(r io.Reader, n int64) io.Reader { return &limitedReader{r, n} }
+func limitReader(r io.Reader, m, n int64) io.Reader { return &limitedReader{r, m, n} }
 
 func (l *limitedReader) Read(p []byte) (n int, err error) {
 	n, err = l.R.Read(p)
 	l.N -= int64(n)
+	l.M -= int64(n)
 	if l.N < 0 {
 		// If more data is available than what is expected we return error.
 		return 0, errDataTooLarge
 	}
+	if err == io.EOF && l.M > 0 {
+		return 0, errDataTooSmall
+	}
 	return
 }

cmd/object-utils_test.go

@@ -120,17 +120,20 @@ func TestIsValidObjectName(t *testing.T) {
 func TestLimitReader(t *testing.T) {
 	testCases := []struct {
 		data   string
+		minLen int64
 		maxLen int64
 		err    error
 	}{
-		{"1234567890", 15, nil},
-		{"1234567890", 10, nil},
-		{"1234567890", 5, errDataTooLarge},
+		{"1234567890", 0, 15, nil},
+		{"1234567890", 0, 10, nil},
+		{"1234567890", 0, 5, errDataTooLarge},
+		{"123", 5, 10, errDataTooSmall},
+		{"123", 2, 10, nil},
 	}
 
 	for i, test := range testCases {
 		r := strings.NewReader(test.data)
-		_, err := ioutil.ReadAll(limitReader(r, test.maxLen))
+		_, err := ioutil.ReadAll(limitReader(r, test.minLen, test.maxLen))
 		if err != test.err {
 			t.Fatalf("test %d failed: expected %v, got %v", i+1, test.err, err)
 		}

cmd/signature-v4-postpolicyform.go

@@ -17,7 +17,6 @@
 package cmd
 
 import (
-	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"reflect"
@@ -52,6 +51,13 @@ func isString(val interface{}) bool {
 	return false
 }
 
+// ContentLengthRange - policy content-length-range field.
+type contentLengthRange struct {
+	Min   int
+	Max   int
+	Valid bool // If content-length-range was part of policy
+}
+
 // PostPolicyForm provides strict static type conversion and validation for Amazon S3's POST policy JSON string.
 type PostPolicyForm struct {
 	Expiration time.Time // Expiration date and time of the POST policy.
@@ -60,10 +66,7 @@ type PostPolicyForm struct {
 			Operator string
 			Value    string
 		}
-		ContentLengthRange struct {
-			Min int
-			Max int
-		}
+		ContentLengthRange contentLengthRange
 	}
 }
 
@@ -133,13 +136,7 @@ func parsePostPolicyFormV4(policy string) (PostPolicyForm, error) {
 					Value:    value,
 				}
 			case "content-length-range":
-				parsedPolicy.Conditions.ContentLengthRange = struct {
-					Min int
-					Max int
-				}{
-					Min: toInteger(condt[1]),
-					Max: toInteger(condt[2]),
-				}
+				parsedPolicy.Conditions.ContentLengthRange = contentLengthRange{toInteger(condt[1]), toInteger(condt[2]), true}
 			default:
 				// Condition should be valid.
 				return parsedPolicy, fmt.Errorf("Unknown type %s of conditional field value %s found in POST policy form.", reflect.TypeOf(condt).String(), condt)
@@ -152,16 +149,7 @@ func parsePostPolicyFormV4(policy string) (PostPolicyForm, error) {
 }
 
 // checkPostPolicy - apply policy conditions and validate input values.
-func checkPostPolicy(formValues map[string]string) APIErrorCode {
-	/// Decoding policy
-	policyBytes, err := base64.StdEncoding.DecodeString(formValues["Policy"])
-	if err != nil {
-		return ErrMalformedPOSTRequest
-	}
-	postPolicyForm, err := parsePostPolicyFormV4(string(policyBytes))
-	if err != nil {
-		return ErrMalformedPOSTRequest
-	}
+func checkPostPolicy(formValues map[string]string, postPolicyForm PostPolicyForm) APIErrorCode {
 	if !postPolicyForm.Expiration.After(time.Now().UTC()) {
 		return ErrPolicyAlreadyExpired
 	}

cmd/signature-v4-postpolicyform_test.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"encoding/base64"
 	"testing"
 )
 
@@ -33,8 +34,6 @@ func TestPostPolicyForm(t *testing.T) {
 		ErrCode       APIErrorCode
 	}
 	testCases := []testCase{
-		// Mal formed policy document
-		{Bucket: "testbucket", Key: "user/user1/filename/${filename}/myfile.txt", XAmzDate: "20160727T000000Z", XAmzAlgorithm: "AWS4-HMAC-SHA256", ContentType: "image/jpeg", Policy: "==", ErrCode: ErrMalformedPOSTRequest},
 		// Different AMZ date
 		{Bucket: "testbucket", Key: "user/user1/filename/${filename}/myfile.txt", XAmzDate: "20160727T000000Z", XAmzAlgorithm: "AWS4-HMAC-SHA256", ContentType: "image/jpeg", Policy: "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", ErrCode: ErrAccessDenied},
 		// Key which doesn't start with user/user1/filename
@@ -51,10 +50,18 @@ func TestPostPolicyForm(t *testing.T) {
 		formValues["X-Amz-Algorithm"] = tt.XAmzAlgorithm
 		formValues["Content-Type"] = tt.ContentType
 		formValues["Policy"] = tt.Policy
+		policyBytes, err := base64.StdEncoding.DecodeString(tt.Policy)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-		err := checkPostPolicy(formValues)
-		if tt.ErrCode != err {
-			t.Errorf("Test %d:, Expected %d, got %d", i+1, tt.ErrCode, err)
+		postPolicyForm, err := parsePostPolicyFormV4(string(policyBytes))
+		if err != nil {
+			t.Fatal(err)
+		}
+		errCode := checkPostPolicy(formValues, postPolicyForm)
+		if tt.ErrCode != errCode {
+			t.Errorf("Test %d:, Expected %d, got %d", i+1, tt.ErrCode, errCode)
 		}
 	}
 }

cmd/typed-errors.go

@@ -38,3 +38,6 @@ var errSizeUnexpected = errors.New("Data size larger than expected")
 
 // When upload object size is greater than 5G in a single PUT/POST operation.
 var errDataTooLarge = errors.New("Object size larger than allowed limit")
+
+// When upload object size is less than what was expected.
+var errDataTooSmall = errors.New("Object size smaller than expected")