mirror of https://github.com/grafana/grafana.git
54 lines
1.6 KiB
Go
54 lines
1.6 KiB
Go
package middleware
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import (
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"crypto/rand"
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"encoding/base64"
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"fmt"
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"io"
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"net/http"
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"regexp"
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"strings"
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"github.com/grafana/grafana/pkg/infra/log"
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"github.com/grafana/grafana/pkg/services/contexthandler"
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"github.com/grafana/grafana/pkg/setting"
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)
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// AddCSPHeader adds the Content Security Policy header.
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func AddCSPHeader(cfg *setting.Cfg, logger log.Logger) func(http.Handler) http.Handler {
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return func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
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if !cfg.CSPEnabled {
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next.ServeHTTP(rw, req)
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return
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}
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logger.Debug("Adding CSP header to response", "cfg", fmt.Sprintf("%p", cfg))
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ctx := contexthandler.FromContext(req.Context())
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if cfg.CSPTemplate == "" {
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logger.Debug("CSP template not configured, so returning 500")
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ctx.JsonApiErr(500, "CSP template has to be configured", nil)
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return
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}
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var buf [16]byte
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if _, err := io.ReadFull(rand.Reader, buf[:]); err != nil {
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logger.Error("Failed to generate CSP nonce", "err", err)
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ctx.JsonApiErr(500, "Failed to generate CSP nonce", err)
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}
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nonce := base64.RawStdEncoding.EncodeToString(buf[:])
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val := strings.ReplaceAll(cfg.CSPTemplate, "$NONCE", fmt.Sprintf("'nonce-%s'", nonce))
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re := regexp.MustCompile(`^\w+:(//)?`)
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rootPath := re.ReplaceAllString(cfg.AppURL, "")
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val = strings.ReplaceAll(val, "$ROOT_PATH", rootPath)
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rw.Header().Set("Content-Security-Policy", val)
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ctx.RequestNonce = nonce
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logger.Debug("Successfully generated CSP nonce", "nonce", nonce)
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next.ServeHTTP(rw, req)
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})
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}
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}
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