1 files changed, 241 insertions, 0 deletions
diff --git a/weed/s3api/s3api_object_handlers_postpolicy.go b/weed/s3api/s3api_object_handlers_postpolicy.go
new file mode 100644
index 000000000..035302ae6
--- /dev/null
+++ b/weed/s3api/s3api_object_handlers_postpolicy.go
@@ -0,0 +1,241 @@
+package s3api
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/s3api/policy"
+	"github.com/chrislusf/seaweedfs/weed/s3api/s3err"
+	"github.com/dustin/go-humanize"
+	"github.com/gorilla/mux"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+func (s3a *S3ApiServer) PostPolicyBucketHandler(w http.ResponseWriter, r *http.Request) {
+
+	// https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-HTTPPOSTConstructPolicy.html
+	// https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-post-example.html
+
+	bucket := mux.Vars(r)["bucket"]
+
+	reader, err := r.MultipartReader()
+	if err != nil {
+		writeErrorResponse(w, s3err.ErrMalformedPOSTRequest, r.URL)
+		return
+	}
+	form, err := reader.ReadForm(int64(5 * humanize.MiByte))
+	if err != nil {
+		writeErrorResponse(w, s3err.ErrMalformedPOSTRequest, r.URL)
+		return
+	}
+	defer form.RemoveAll()
+
+	fileBody, fileName, fileSize, formValues, err := extractPostPolicyFormValues(form)
+	if err != nil {
+		writeErrorResponse(w, s3err.ErrMalformedPOSTRequest, r.URL)
+		return
+	}
+	if fileBody == nil {
+		writeErrorResponse(w, s3err.ErrPOSTFileRequired, r.URL)
+		return
+	}
+	defer fileBody.Close()
+
+	formValues.Set("Bucket", bucket)
+
+	if fileName != "" && strings.Contains(formValues.Get("Key"), "${filename}") {
+		formValues.Set("Key", strings.Replace(formValues.Get("Key"), "${filename}", fileName, -1))
+	}
+	object := formValues.Get("Key")
+
+	successRedirect := formValues.Get("success_action_redirect")
+	successStatus := formValues.Get("success_action_status")
+	var redirectURL *url.URL
+	if successRedirect != "" {
+		redirectURL, err = url.Parse(successRedirect)
+		if err != nil {
+			writeErrorResponse(w, s3err.ErrMalformedPOSTRequest, r.URL)
+			return
+		}
+	}
+
+	// Verify policy signature.
+	errCode := s3a.iam.doesPolicySignatureMatch(formValues)
+	if errCode != s3err.ErrNone {
+		writeErrorResponse(w, errCode, r.URL)
+		return
+	}
+
+	policyBytes, err := base64.StdEncoding.DecodeString(formValues.Get("Policy"))
+	if err != nil {
+		writeErrorResponse(w, s3err.ErrMalformedPOSTRequest, r.URL)
+		return
+	}
+
+	// Handle policy if it is set.
+	if len(policyBytes) > 0 {
+
+		postPolicyForm, err := policy.ParsePostPolicyForm(string(policyBytes))
+		if err != nil {
+			writeErrorResponse(w, s3err.ErrPostPolicyConditionInvalidFormat, r.URL)
+			return
+		}
+
+		// Make sure formValues adhere to policy restrictions.
+		if err = policy.CheckPostPolicy(formValues, postPolicyForm); err != nil {
+			w.Header().Set("Location", r.URL.Path)
+			w.WriteHeader(http.StatusTemporaryRedirect)
+			return
+		}
+
+		// Ensure that the object size is within expected range, also the file size
+		// should not exceed the maximum single Put size (5 GiB)
+		lengthRange := postPolicyForm.Conditions.ContentLengthRange
+		if lengthRange.Valid {
+			if fileSize < lengthRange.Min {
+				writeErrorResponse(w, s3err.ErrEntityTooSmall, r.URL)
+				return
+			}
+
+			if fileSize > lengthRange.Max {
+				writeErrorResponse(w, s3err.ErrEntityTooLarge, r.URL)
+				return
+			}
+		}
+	}
+
+	uploadUrl := fmt.Sprintf("http://%s%s/%s%s", s3a.option.Filer, s3a.option.BucketsPath, bucket, urlPathEscape(object))
+
+	etag, errCode := s3a.putToFiler(r, uploadUrl, fileBody)
+
+	if errCode != s3err.ErrNone {
+		writeErrorResponse(w, errCode, r.URL)
+		return
+	}
+
+	if successRedirect != "" {
+		// Replace raw query params..
+		redirectURL.RawQuery = getRedirectPostRawQuery(bucket, object, etag)
+		w.Header().Set("Location", redirectURL.String())
+		writeResponse(w, http.StatusSeeOther, nil, mimeNone)
+		return
+	}
+
+	setEtag(w, etag)
+
+	// Decide what http response to send depending on success_action_status parameter
+	switch successStatus {
+	case "201":
+		resp := encodeResponse(PostResponse{
+			Bucket:   bucket,
+			Key:      object,
+			ETag:     `"` + etag + `"`,
+			Location: w.Header().Get("Location"),
+		})
+		writeResponse(w, http.StatusCreated, resp, mimeXML)
+	case "200":
+		writeResponse(w, http.StatusOK, nil, mimeNone)
+	default:
+		writeSuccessResponseEmpty(w)
+	}
+
+}
+
+// Extract form fields and file data from a HTTP POST Policy
+func extractPostPolicyFormValues(form *multipart.Form) (filePart io.ReadCloser, fileName string, fileSize int64, formValues http.Header, err error) {
+	/// HTML Form values
+	fileName = ""
+
+	// Canonicalize the form values into http.Header.
+	formValues = make(http.Header)
+	for k, v := range form.Value {
+		formValues[http.CanonicalHeaderKey(k)] = v
+	}
+
+	// Validate form values.
+	if err = validateFormFieldSize(formValues); err != nil {
+		return nil, "", 0, nil, err
+	}
+
+	// this means that filename="" was not specified for file key and Go has
+	// an ugly way of handling this situation. Refer here
+	// https://golang.org/src/mime/multipart/formdata.go#L61
+	if len(form.File) == 0 {
+		var b = &bytes.Buffer{}
+		for _, v := range formValues["File"] {
+			b.WriteString(v)
+		}
+		fileSize = int64(b.Len())
+		filePart = ioutil.NopCloser(b)
+		return filePart, fileName, fileSize, formValues, nil
+	}
+
+	// Iterator until we find a valid File field and break
+	for k, v := range form.File {
+		canonicalFormName := http.CanonicalHeaderKey(k)
+		if canonicalFormName == "File" {
+			if len(v) == 0 {
+				return nil, "", 0, nil, errors.New("Invalid arguments specified")
+			}
+			// Fetch fileHeader which has the uploaded file information
+			fileHeader := v[0]
+			// Set filename
+			fileName = fileHeader.Filename
+			// Open the uploaded part
+			filePart, err = fileHeader.Open()
+			if err != nil {
+				return nil, "", 0, nil, err
+			}
+			// Compute file size
+			fileSize, err = filePart.(io.Seeker).Seek(0, 2)
+			if err != nil {
+				return nil, "", 0, nil, err
+			}
+			// Reset Seek to the beginning
+			_, err = filePart.(io.Seeker).Seek(0, 0)
+			if err != nil {
+				return nil, "", 0, nil, err
+			}
+			// File found and ready for reading
+			break
+		}
+	}
+	return filePart, fileName, fileSize, formValues, nil
+}
+
+// Validate form field size for s3 specification requirement.
+func validateFormFieldSize(formValues http.Header) error {
+	// Iterate over form values
+	for k := range formValues {
+		// Check if value's field exceeds S3 limit
+		if int64(len(formValues.Get(k))) > int64(1*humanize.MiByte) {
+			return errors.New("Data size larger than expected")
+		}
+	}
+
+	// Success.
+	return nil
+}
+
+func getRedirectPostRawQuery(bucket, key, etag string) string {
+	redirectValues := make(url.Values)
+	redirectValues.Set("bucket", bucket)
+	redirectValues.Set("key", key)
+	redirectValues.Set("etag", "\""+etag+"\"")
+	return redirectValues.Encode()
+}
+
+// Check to see if Policy is signed correctly.
+func (iam *IdentityAccessManagement) doesPolicySignatureMatch(formValues http.Header) s3err.ErrorCode {
+	// For SignV2 - Signature field will be valid
+	if _, ok := formValues["Signature"]; ok {
+		return iam.doesPolicySignatureV2Match(formValues)
+	}
+	return iam.doesPolicySignatureV4Match(formValues)
+}