From dd136858f1ea40ad3c94191d647487fa4f31926c Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel@debian.org>
Date: Fri, 18 Oct 2024 20:33:49 +0200
Subject: Adding upstream version 9.0.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>
---
 routers/web/auth/webauthn.go | 177 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 177 insertions(+)
 create mode 100644 routers/web/auth/webauthn.go

(limited to 'routers/web/auth/webauthn.go')

diff --git a/routers/web/auth/webauthn.go b/routers/web/auth/webauthn.go
new file mode 100644
index 0000000..5c93c14
--- /dev/null
+++ b/routers/web/auth/webauthn.go
@@ -0,0 +1,177 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package auth
+
+import (
+	"errors"
+	"net/http"
+
+	"code.gitea.io/gitea/models/auth"
+	user_model "code.gitea.io/gitea/models/user"
+	wa "code.gitea.io/gitea/modules/auth/webauthn"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/context"
+	"code.gitea.io/gitea/services/externalaccount"
+
+	"github.com/go-webauthn/webauthn/protocol"
+	"github.com/go-webauthn/webauthn/webauthn"
+)
+
+var tplWebAuthn base.TplName = "user/auth/webauthn"
+
+// WebAuthn shows the WebAuthn login page
+func WebAuthn(ctx *context.Context) {
+	ctx.Data["Title"] = ctx.Tr("twofa")
+
+	if CheckAutoLogin(ctx) {
+		return
+	}
+
+	// Ensure user is in a 2FA session.
+	if ctx.Session.Get("twofaUid") == nil {
+		ctx.ServerError("UserSignIn", errors.New("not in WebAuthn session"))
+		return
+	}
+
+	hasTwoFactor, err := auth.HasTwoFactorByUID(ctx, ctx.Session.Get("twofaUid").(int64))
+	if err != nil {
+		ctx.ServerError("HasTwoFactorByUID", err)
+		return
+	}
+
+	ctx.Data["HasTwoFactor"] = hasTwoFactor
+
+	ctx.HTML(http.StatusOK, tplWebAuthn)
+}
+
+// WebAuthnLoginAssertion submits a WebAuthn challenge to the browser
+func WebAuthnLoginAssertion(ctx *context.Context) {
+	// Ensure user is in a WebAuthn session.
+	idSess, ok := ctx.Session.Get("twofaUid").(int64)
+	if !ok || idSess == 0 {
+		ctx.ServerError("UserSignIn", errors.New("not in WebAuthn session"))
+		return
+	}
+
+	user, err := user_model.GetUserByID(ctx, idSess)
+	if err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+
+	exists, err := auth.ExistsWebAuthnCredentialsForUID(ctx, user.ID)
+	if err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+	if !exists {
+		ctx.ServerError("UserSignIn", errors.New("no device registered"))
+		return
+	}
+
+	assertion, sessionData, err := wa.WebAuthn.BeginLogin((*wa.User)(user))
+	if err != nil {
+		ctx.ServerError("webauthn.BeginLogin", err)
+		return
+	}
+
+	if err := ctx.Session.Set("webauthnAssertion", sessionData); err != nil {
+		ctx.ServerError("Session.Set", err)
+		return
+	}
+	ctx.JSON(http.StatusOK, assertion)
+}
+
+// WebAuthnLoginAssertionPost validates the signature and logs the user in
+func WebAuthnLoginAssertionPost(ctx *context.Context) {
+	idSess, ok := ctx.Session.Get("twofaUid").(int64)
+	sessionData, okData := ctx.Session.Get("webauthnAssertion").(*webauthn.SessionData)
+	if !ok || !okData || sessionData == nil || idSess == 0 {
+		ctx.ServerError("UserSignIn", errors.New("not in WebAuthn session"))
+		return
+	}
+	defer func() {
+		_ = ctx.Session.Delete("webauthnAssertion")
+	}()
+
+	// Load the user from the db
+	user, err := user_model.GetUserByID(ctx, idSess)
+	if err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+
+	log.Trace("Finishing webauthn authentication with user: %s", user.Name)
+
+	// Now we do the equivalent of webauthn.FinishLogin using a combination of our session data
+	// (from webauthnAssertion) and verify the provided request.0
+	parsedResponse, err := protocol.ParseCredentialRequestResponse(ctx.Req)
+	if err != nil {
+		// Failed authentication attempt.
+		log.Info("Failed authentication attempt for %s from %s: %v", user.Name, ctx.RemoteAddr(), err)
+		ctx.Status(http.StatusForbidden)
+		return
+	}
+
+	dbCred, err := auth.GetWebAuthnCredentialByCredID(ctx, user.ID, parsedResponse.RawID)
+	if err != nil {
+		ctx.ServerError("GetWebAuthnCredentialByCredID", err)
+		return
+	}
+
+	// If the credential is legacy, assume the values are correct. The
+	// specification mandates these flags don't change.
+	if dbCred.Legacy {
+		dbCred.BackupEligible = parsedResponse.Response.AuthenticatorData.Flags.HasBackupEligible()
+		dbCred.BackupState = parsedResponse.Response.AuthenticatorData.Flags.HasBackupState()
+		dbCred.Legacy = false
+
+		if err := dbCred.UpdateFromLegacy(ctx); err != nil {
+			ctx.ServerError("UpdateFromLegacy", err)
+			return
+		}
+	}
+
+	// Validate the parsed response.
+	cred, err := wa.WebAuthn.ValidateLogin((*wa.User)(user), *sessionData, parsedResponse)
+	if err != nil {
+		// Failed authentication attempt.
+		log.Info("Failed authentication attempt for %s from %s: %v", user.Name, ctx.RemoteAddr(), err)
+		ctx.Status(http.StatusForbidden)
+		return
+	}
+
+	// Ensure that the credential wasn't cloned by checking if CloneWarning is set.
+	// (This is set if the sign counter is less than the one we have stored.)
+	if cred.Authenticator.CloneWarning {
+		log.Info("Failed authentication attempt for %s from %s: cloned credential", user.Name, ctx.RemoteAddr())
+		ctx.Status(http.StatusForbidden)
+		return
+	}
+
+	dbCred.SignCount = cred.Authenticator.SignCount
+	if err := dbCred.UpdateSignCount(ctx); err != nil {
+		ctx.ServerError("UpdateSignCount", err)
+		return
+	}
+
+	// Now handle account linking if that's requested
+	if ctx.Session.Get("linkAccount") != nil {
+		if err := externalaccount.LinkAccountFromStore(ctx, ctx.Session, user); err != nil {
+			ctx.ServerError("LinkAccountFromStore", err)
+			return
+		}
+	}
+
+	remember := ctx.Session.Get("twofaRemember").(bool)
+	redirect := handleSignInFull(ctx, user, remember, false)
+	if redirect == "" {
+		redirect = setting.AppSubURL + "/"
+	}
+	_ = ctx.Session.Delete("twofaUid")
+
+	ctx.JSONRedirect(redirect)
+}
-- 
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