mirror of
https://github.com/rls-moe/nyx
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102 lines
2.0 KiB
Go
102 lines
2.0 KiB
Go
// +build !go1.7
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package nosurf
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import (
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"net/http"
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"sync"
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)
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// This file implements a context similar to one found
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// in gorilla/context, but tailored specifically for our use case
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// and not using gorilla's package just because.
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type csrfContext struct {
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// The masked, base64 encoded token
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// That's suitable for use in form fields, etc.
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token string
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// reason for the failure of CSRF check
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reason error
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}
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var (
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contextMap = make(map[*http.Request]*csrfContext)
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cmMutex = new(sync.RWMutex)
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)
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// Token() takes an HTTP request and returns
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// the CSRF token for that request
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// or an empty string if the token does not exist.
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//
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// Note that the token won't be available after
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// CSRFHandler finishes
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// (that is, in another handler that wraps it,
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// or after the request has been served)
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func Token(req *http.Request) string {
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cmMutex.RLock()
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defer cmMutex.RUnlock()
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ctx, ok := contextMap[req]
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if !ok {
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return ""
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}
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return ctx.token
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}
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// Reason() takes an HTTP request and returns
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// the reason of failure of the CSRF check for that request
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//
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// Note that the same availability restrictions apply for Reason() as for Token().
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func Reason(req *http.Request) error {
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cmMutex.RLock()
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defer cmMutex.RUnlock()
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ctx, ok := contextMap[req]
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if !ok {
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return nil
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}
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return ctx.reason
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}
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// Takes a raw token, masks it with a per-request key,
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// encodes in base64 and makes it available to the wrapped handler
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func ctxSetToken(req *http.Request, token []byte) *http.Request {
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cmMutex.Lock()
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defer cmMutex.Unlock()
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ctx, ok := contextMap[req]
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if !ok {
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ctx = new(csrfContext)
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contextMap[req] = ctx
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}
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ctx.token = b64encode(maskToken(token))
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return req
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}
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func ctxSetReason(req *http.Request, reason error) *http.Request {
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cmMutex.Lock()
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defer cmMutex.Unlock()
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ctx, ok := contextMap[req]
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if !ok {
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panic("Reason should never be set when there's no token" +
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" (context) yet.")
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}
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ctx.reason = reason
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return req
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}
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func ctxClear(req *http.Request) {
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cmMutex.Lock()
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defer cmMutex.Unlock()
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delete(contextMap, req)
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}
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