commento/api/oauth_sso_redirect.go

83 lines
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package main
import (
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"fmt"
"net/http"
"net/url"
)
func ssoRedirectHandler(w http.ResponseWriter, r *http.Request) {
commenterToken := r.FormValue("commenterToken")
domain := r.Header.Get("Referer")
if commenterToken == "" {
fmt.Fprintf(w, "Error: %s\n", errorMissingField.Error())
return
}
domain = domainStrip(domain)
if domain == "" {
fmt.Fprintf(w, "Error: No Referer header found in request\n")
return
}
_, err := commenterGetByCommenterToken(commenterToken)
if err != nil && err != errorNoSuchToken {
fmt.Fprintf(w, "Error: %s\n", err.Error())
return
}
d, err := domainGet(domain)
if err != nil {
fmt.Fprintf(w, "Error: %s\n", errorNoSuchDomain.Error())
return
}
if !d.SsoProvider {
fmt.Fprintf(w, "Error: SSO not configured for %s\n", domain)
return
}
if d.SsoSecret == "" || d.SsoUrl == "" {
fmt.Fprintf(w, "Error: %s\n", errorMissingConfig.Error())
return
}
key, err := hex.DecodeString(d.SsoSecret)
if err != nil {
logger.Errorf("cannot decode SSO secret as hex: %v", err)
fmt.Fprintf(w, "Error: %s\n", err.Error())
return
}
tokenBytes, err := hex.DecodeString(commenterToken)
if err != nil {
logger.Errorf("cannot decode hex commenterToken: %v", err)
fmt.Fprintf(w, "Error: %s\n", errorInternal.Error())
return
}
h := hmac.New(sha256.New, key)
h.Write(tokenBytes)
signature := hex.EncodeToString(h.Sum(nil))
u, err := url.Parse(d.SsoUrl)
if err != nil {
// this should really not be happening; we're checking if the
// passed URL is valid at domain update
logger.Errorf("cannot parse URL: %v", err)
fmt.Fprintf(w, "Error: %s\n", errorInternal.Error())
return
}
q := u.Query()
q.Set("token", commenterToken)
q.Set("hmac", signature)
u.RawQuery = q.Encode()
http.Redirect(w, r, u.String(), http.StatusFound)
}