parent
c5f0bbc687
commit
a214a7e9e8
GPG Key ID:
1F14E25B7C119FC5
3 changed files with 342 additions and 243 deletions
@ -0,0 +1,159 @@ |
||||
package middleware |
||||
|
||||
import ( |
||||
"bytes" |
||||
"errors" |
||||
"fmt" |
||||
"net/textproto" |
||||
"strings" |
||||
|
||||
http "github.com/valyala/fasthttp" |
||||
) |
||||
|
||||
// ValuesExtractor defines a function for extracting values (keys/tokens) from
|
||||
// the given context.
|
||||
type ValuesExtractor func(ctx *http.RequestCtx) ([][]byte, error) |
||||
|
||||
const ( |
||||
// extractorLimit is arbitrary number to limit values extractor can
|
||||
// return. this limits possible resource exhaustion attack vector.
|
||||
extractorLimit = 20 |
||||
) |
||||
|
||||
var ( |
||||
errHeaderExtractorValueMissing = errors.New("missing value in request header") |
||||
errHeaderExtractorValueInvalid = errors.New("invalid value in request header") |
||||
errQueryExtractorValueMissing = errors.New("missing value in the query string") |
||||
errParamExtractorValueMissing = errors.New("missing value in path params") |
||||
errCookieExtractorValueMissing = errors.New("missing value in cookies") |
||||
errFormExtractorValueMissing = errors.New("missing value in the form") |
||||
) |
||||
|
||||
func createExtractors(lookups, authScheme string) ([]ValuesExtractor, error) { |
||||
if lookups == "" { |
||||
return nil, nil |
||||
} |
||||
|
||||
sources := strings.Split(lookups, ",") |
||||
extractors := make([]ValuesExtractor, 0) |
||||
|
||||
for _, source := range sources { |
||||
parts := strings.Split(source, ":") |
||||
|
||||
if len(parts) < 2 { |
||||
return nil, fmt.Errorf("extractor source for lookup could not be split into needed parts: %s", |
||||
source) |
||||
} |
||||
|
||||
switch parts[0] { |
||||
case "query": |
||||
extractors = append(extractors, valuesFromQuery(parts[1])) |
||||
case "cookie": |
||||
extractors = append(extractors, valuesFromCookie(parts[1])) |
||||
case "form": |
||||
extractors = append(extractors, valuesFromForm(parts[1])) |
||||
case "header": |
||||
prefix := "" |
||||
|
||||
if len(parts) > 2 { |
||||
prefix = parts[2] |
||||
} else if authScheme != "" && parts[1] == http.HeaderAuthorization { |
||||
// backwards compatibility for JWT and KeyAuth:
|
||||
// * we only apply this fix to Authorization as header we use and uses prefixes like "Bearer <token-value>" etc
|
||||
// * previously header extractor assumed that auth-scheme/prefix had a space as suffix we need to retain that
|
||||
// behaviour for default values and Authorization header.
|
||||
prefix = authScheme |
||||
|
||||
if !strings.HasSuffix(prefix, " ") { |
||||
prefix += " " |
||||
} |
||||
} |
||||
|
||||
extractors = append(extractors, valuesFromHeader(parts[1], prefix)) |
||||
} |
||||
} |
||||
|
||||
return extractors, nil |
||||
} |
||||
|
||||
// valuesFromHeader returns a functions that extracts values from the request header.
|
||||
// valuePrefix is parameter to remove first part (prefix) of the extracted value. This is useful if header value has static
|
||||
// prefix like `Authorization: <auth-scheme> <authorisation-parameters>` where part that we want to remove is `<auth-scheme> `
|
||||
// note the space at the end. In case of basic authentication `Authorization: Basic <credentials>` prefix we want to remove
|
||||
// is `Basic `. In case of JWT tokens `Authorization: Bearer <token>` prefix is `Bearer `.
|
||||
// If prefix is left empty the whole value is returned.
|
||||
func valuesFromHeader(header, valuePrefix string) ValuesExtractor { |
||||
prefixLen := len(valuePrefix) |
||||
// standard library parses http.Request header keys in canonical form but we may provide something else so fix this
|
||||
header = textproto.CanonicalMIMEHeaderKey(header) |
||||
|
||||
return func(ctx *http.RequestCtx) ([][]byte, error) { |
||||
value := ctx.Request.Header.Peek(header) |
||||
if len(value) == 0 { |
||||
return nil, errHeaderExtractorValueMissing |
||||
} |
||||
|
||||
if prefixLen == 0 { |
||||
return append([][]byte{}, value), nil |
||||
} |
||||
|
||||
if len(value) > prefixLen && bytes.EqualFold(value[:prefixLen], []byte(valuePrefix)) { |
||||
return append([][]byte{}, value[:prefixLen]), nil |
||||
} |
||||
|
||||
return nil, errHeaderExtractorValueInvalid |
||||
} |
||||
} |
||||
|
||||
// valuesFromQuery returns a function that extracts values from the query string.
|
||||
func valuesFromQuery(param string) ValuesExtractor { |
||||
return func(ctx *http.RequestCtx) ([][]byte, error) { |
||||
if !ctx.QueryArgs().Has(param) { |
||||
return nil, errQueryExtractorValueMissing |
||||
} |
||||
|
||||
result := ctx.QueryArgs().PeekMulti(param) |
||||
if len(result) > extractorLimit-1 { |
||||
result = result[:extractorLimit] |
||||
} |
||||
|
||||
return result, nil |
||||
} |
||||
} |
||||
|
||||
// valuesFromCookie returns a function that extracts values from the named cookie.
|
||||
func valuesFromCookie(name string) ValuesExtractor { |
||||
return func(ctx *http.RequestCtx) ([][]byte, error) { |
||||
if value := ctx.Request.Header.Cookie(name); len(value) != 0 { |
||||
return append([][]byte{}, value), nil |
||||
} |
||||
|
||||
return nil, errCookieExtractorValueMissing |
||||
} |
||||
} |
||||
|
||||
// valuesFromForm returns a function that extracts values from the form field.
|
||||
func valuesFromForm(name string) ValuesExtractor { |
||||
return func(ctx *http.RequestCtx) ([][]byte, error) { |
||||
form, err := ctx.MultipartForm() |
||||
if err != nil { |
||||
return nil, fmt.Errorf("valuesFromForm parse form failed: %w", err) |
||||
} |
||||
|
||||
values := form.Value[name] |
||||
|
||||
switch { |
||||
case len(values) == 0: |
||||
return nil, errFormExtractorValueMissing |
||||
case len(values) > extractorLimit-1: |
||||
values = values[:extractorLimit] |
||||
} |
||||
|
||||
result := make([][]byte, 0) |
||||
for i := range values { |
||||
result = append(result, []byte(values[i])) |
||||
} |
||||
|
||||
return result, nil |
||||
} |
||||
} |
||||
Loading…
Reference in new issue