mattermost/server/channels/app/bot.go
David Krauser c0c2ff2ad9
[MM-67314] Fix system bot DM restriction bypass (#35477)
When TeamSettings.RestrictDirectMessage is set to "team", the system bot could not create DM channels with users on different teams (or no shared team). This broke SendTestMessage, CheckPostReminders, and other background jobs that use an empty session context.

The existing bypass in GetOrCreateDirectChannel only covered bots owned by the current session user or a plugin. The system bot is owned by a system admin, so it failed the ownership check and hit the common-team guard.

Changes:
- Rename IsBotOwnedByCurrentUserOrPlugin to IsBotExemptFromDMRestrictions to better reflect its purpose
- Add an explicit system bot exemption (bot.Username == BotSystemBotUsername) as the first check in the function
- Add tests covering the system bot exemption with both empty and user sessions
2026-03-09 14:08:30 -04:00

686 lines
22 KiB
Go

// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
package app
import (
"context"
"errors"
"fmt"
"net/http"
"github.com/mattermost/mattermost/server/public/model"
"github.com/mattermost/mattermost/server/public/shared/i18n"
"github.com/mattermost/mattermost/server/public/shared/mlog"
"github.com/mattermost/mattermost/server/public/shared/request"
"github.com/mattermost/mattermost/server/v8/channels/store"
)
const (
internalKeyPrefix = "mmi_"
botUserKey = internalKeyPrefix + "botid"
)
// EnsureBot provides similar functionality with the plugin-api BotService. It doesn't accept
// any ensureBotOptions hence it is not required for now.
func (a *App) EnsureBot(rctx request.CTX, pluginID string, bot *model.Bot) (string, error) {
if bot == nil {
return "", errors.New("passed a nil bot")
}
if bot.Username == "" {
return "", errors.New("passed a bot with no username")
}
botIDBytes, appErr := a.GetPluginKey(pluginID, botUserKey)
if appErr != nil {
return "", appErr
}
// If the bot has already been created, check whether it still exists and use it
if botIDBytes != nil {
botID := string(botIDBytes)
if _, appErr = a.GetBot(rctx, botID, true); appErr != nil {
rctx.Logger().Debug("Unable to get bot.", mlog.String("bot_id", botID), mlog.Err(appErr))
} else {
// ensure existing bot is synced with what is being created
botPatch := &model.BotPatch{
Username: &bot.Username,
DisplayName: &bot.DisplayName,
Description: &bot.Description,
}
if _, appErr = a.PatchBot(rctx, botID, botPatch); appErr != nil {
return "", fmt.Errorf("failed to patch bot: %w", appErr)
}
return botID, nil
}
}
// Check for an existing bot user with that username. If one exists, then use that.
if user, appErr := a.GetUserByUsername(bot.Username); appErr == nil && user != nil {
if user.IsBot {
if appErr := a.SetPluginKey(pluginID, botUserKey, []byte(user.Id)); appErr != nil {
return "", fmt.Errorf("failed to set plugin key: %w", appErr)
}
} else {
rctx.Logger().Error("Plugin attempted to use an account that already exists. Convert user to a bot "+
"account in the CLI by running 'mattermost user convert <username> --bot'. If the user is an "+
"existing user account you want to preserve, change its username and restart the Mattermost server, "+
"after which the plugin will create a bot account with that name. For more information about bot "+
"accounts, see https://mattermost.com/pl/default-bot-accounts", mlog.String("username",
bot.Username),
mlog.String("user_id",
user.Id),
)
}
return user.Id, nil
}
createdBot, err := a.CreateBot(rctx, bot)
if err != nil {
return "", fmt.Errorf("failed to create bot: %w", err)
}
if appErr := a.SetPluginKey(pluginID, botUserKey, []byte(createdBot.UserId)); appErr != nil {
return "", fmt.Errorf("failed to set plugin key: %w", appErr)
}
return createdBot.UserId, nil
}
// CreateBot creates the given bot and corresponding user.
func (a *App) CreateBot(rctx request.CTX, bot *model.Bot) (*model.Bot, *model.AppError) {
vErr := bot.IsValidCreate()
if vErr != nil {
return nil, vErr
}
user, nErr := a.Srv().Store().User().Save(rctx, model.UserFromBot(bot))
if nErr != nil {
var appErr *model.AppError
var invErr *store.ErrInvalidInput
switch {
case errors.As(nErr, &appErr):
return nil, appErr
case errors.As(nErr, &invErr):
code := ""
switch invErr.Field {
case "email":
code = "app.user.save.email_exists.app_error"
case "username":
code = "app.user.save.username_exists.app_error"
default:
code = "app.user.save.existing.app_error"
}
return nil, model.NewAppError("CreateBot", code, nil, "", http.StatusBadRequest).Wrap(nErr)
default:
return nil, model.NewAppError("CreateBot", "app.user.save.app_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
bot.UserId = user.Id
savedBot, nErr := a.Srv().Store().Bot().Save(bot)
if nErr != nil {
if err := a.Srv().Store().User().PermanentDelete(rctx, bot.UserId); err != nil {
rctx.Logger().Error("Failed to permanently delete the user after bot save failure", mlog.Err(err))
}
var appErr *model.AppError
switch {
case errors.As(nErr, &appErr): // in case we haven't converted to plain error.
return nil, appErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("CreateBot", "app.bot.createbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
// Get the owner of the bot, if one exists. If not, don't send a message
ownerUser, err := a.Srv().Store().User().Get(context.Background(), bot.OwnerId)
var nfErr *store.ErrNotFound
if err != nil && !errors.As(err, &nfErr) {
return nil, model.NewAppError("CreateBot", "app.user.get.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
} else if ownerUser != nil {
// Send a message to the bot's creator to inform them that the bot needs to be added
// to a team and channel after it's created
channel, err := a.getOrCreateDirectChannelWithUser(rctx, user, ownerUser)
if err != nil {
return nil, err
}
T := i18n.GetUserTranslations(ownerUser.Locale)
botAddPost := &model.Post{
Type: model.PostTypeAddBotTeamsChannels,
UserId: savedBot.UserId,
ChannelId: channel.Id,
Message: T("api.bot.teams_channels.add_message_mobile"),
}
if _, _, err := a.CreatePostAsUser(rctx, botAddPost, rctx.Session().Id, true); err != nil {
return nil, err
}
}
return savedBot, nil
}
func (a *App) GetSystemBot(rctx request.CTX) (*model.Bot, *model.AppError) {
return a.GetOrCreateSystemOwnedBot(rctx, model.BotSystemBotUsername, i18n.T("app.system.system_bot.bot_displayname"))
}
func (a *App) GetOrCreateSystemOwnedBot(rctx request.CTX, botUsername, botDisplayName string) (*model.Bot, *model.AppError) {
perPage := 1
userOptions := &model.UserGetOptions{
Page: 0,
PerPage: perPage,
Role: model.SystemAdminRoleId,
Inactive: false,
}
sysAdminList, err := a.GetUsersFromProfiles(userOptions)
if err != nil {
return nil, err
}
if len(sysAdminList) == 0 {
return nil, model.NewAppError("GetSystemBot", "app.bot.get_system_bot.empty_admin_list.app_error", nil, "", http.StatusInternalServerError)
}
systemBot := &model.Bot{
Username: botUsername,
DisplayName: botDisplayName,
Description: "",
OwnerId: sysAdminList[0].Id,
}
return a.getOrCreateBot(rctx, systemBot)
}
func (a *App) getOrCreateBot(rctx request.CTX, botDef *model.Bot) (*model.Bot, *model.AppError) {
botUser, appErr := a.GetUserByUsername(botDef.Username)
if appErr != nil {
if appErr.StatusCode != http.StatusNotFound {
return nil, appErr
}
// cannot find this bot user, save the user
user, nErr := a.Srv().Store().User().Save(rctx, model.UserFromBot(botDef))
if nErr != nil {
var appError *model.AppError
var invErr *store.ErrInvalidInput
switch {
case errors.As(nErr, &appError):
return nil, appError
case errors.As(nErr, &invErr):
code := ""
switch invErr.Field {
case "email":
code = "app.user.save.email_exists.app_error"
case "username":
code = "app.user.save.username_exists.app_error"
default:
code = "app.user.save.existing.app_error"
}
return nil, model.NewAppError("getOrCreateBot", code, nil, "", http.StatusBadRequest).Wrap(nErr)
default:
return nil, model.NewAppError("getOrCreateBot", "app.user.save.app_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
botDef.UserId = user.Id
//save the bot
savedBot, nErr := a.Srv().Store().Bot().Save(botDef)
if nErr != nil {
if err := a.Srv().Store().User().PermanentDelete(rctx, savedBot.UserId); err != nil {
rctx.Logger().Error("Failed to permanently delete the user after bot save failure", mlog.Err(err))
}
var nAppErr *model.AppError
switch {
case errors.As(nErr, &nAppErr): // in case we haven't converted to plain error.
return nil, nAppErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("getOrCreateBot", "app.bot.createbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
return savedBot, nil
}
if botUser == nil {
return nil, model.NewAppError("getOrCreateBot", "app.bot.createbot.internal_error", nil, "", http.StatusInternalServerError)
}
//return the bot for this user
savedBot, appErr := a.GetBot(rctx, botUser.Id, false)
if appErr != nil {
return nil, appErr
}
return savedBot, nil
}
// PatchBot applies the given patch to the bot and corresponding user.
func (a *App) PatchBot(rctx request.CTX, botUserId string, botPatch *model.BotPatch) (*model.Bot, *model.AppError) {
bot, err := a.GetBot(rctx, botUserId, true)
if err != nil {
return nil, err
}
if !bot.WouldPatch(botPatch) {
return bot, nil
}
bot.Patch(botPatch)
user, nErr := a.Srv().Store().User().Get(context.Background(), botUserId)
if nErr != nil {
var nfErr *store.ErrNotFound
switch {
case errors.As(nErr, &nfErr):
return nil, model.NewAppError("PatchBot", MissingAccountError, nil, "", http.StatusNotFound).Wrap(nErr)
default:
return nil, model.NewAppError("PatchBot", "app.user.get.app_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
patchedUser := model.UserFromBot(bot)
user.Id = patchedUser.Id
user.Username = patchedUser.Username
user.Email = patchedUser.Email
user.FirstName = patchedUser.FirstName
userUpdate, nErr := a.Srv().Store().User().Update(rctx, user, true)
if nErr != nil {
var appErr *model.AppError
var invErr *store.ErrInvalidInput
var conErr *store.ErrConflict
switch {
case errors.As(nErr, &appErr):
return nil, appErr
case errors.As(nErr, &invErr):
return nil, model.NewAppError("PatchBot", "app.user.update.find.app_error", nil, "", http.StatusBadRequest).Wrap(nErr)
case errors.As(nErr, &conErr):
if conErr.Resource == "Username" {
return nil, model.NewAppError("PatchBot", "app.user.save.username_exists.app_error", nil, "", http.StatusBadRequest).Wrap(nErr)
}
return nil, model.NewAppError("PatchBot", "app.user.save.email_exists.app_error", nil, "", http.StatusBadRequest).Wrap(nErr)
default:
return nil, model.NewAppError("PatchBot", "app.user.update.finding.app_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
a.InvalidateCacheForUser(user.Id)
ruser := userUpdate.New
a.sendUpdatedUserEvent(ruser)
bot, nErr = a.Srv().Store().Bot().Update(bot)
if nErr != nil {
var nfErr *store.ErrNotFound
var appErr *model.AppError
switch {
case errors.As(nErr, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(nErr)
case errors.As(nErr, &appErr): // in case we haven't converted to plain error.
return nil, appErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("PatchBot", "app.bot.patchbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
return bot, nil
}
// GetBot returns the given bot.
func (a *App) GetBot(rctx request.CTX, botUserId string, includeDeleted bool) (*model.Bot, *model.AppError) {
bot, err := a.Srv().Store().Bot().Get(botUserId, includeDeleted)
if err != nil {
var nfErr *store.ErrNotFound
switch {
case errors.As(err, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(err)
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("GetBot", "app.bot.getbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
}
return bot, nil
}
// GetBots returns the requested page of bots.
func (a *App) GetBots(rctx request.CTX, options *model.BotGetOptions) (model.BotList, *model.AppError) {
bots, err := a.Srv().Store().Bot().GetAll(options)
if err != nil {
return nil, model.NewAppError("GetBots", "app.bot.getbots.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
return bots, nil
}
// IsBotExemptFromDMRestrictions checks if the given user ID is a bot that is
// exempt from the RestrictDirectMessage=team enforcement. This includes the
// system bot, bots owned by the current session's user, and plugin-owned bots.
func (a *App) IsBotExemptFromDMRestrictions(rctx request.CTX, userID string) (bool, *model.AppError) {
bot, appErr := a.GetBot(rctx, userID, false)
if appErr != nil {
return false, appErr
}
// The system bot must be able to send messages to any user regardless of
// team membership (e.g. push notification tests, post reminders, etc.)
if bot.Username == model.BotSystemBotUsername {
return true, nil
}
if session := rctx.Session(); session != nil && bot.OwnerId == session.UserId {
return true, nil
}
pluginsEnvironment := a.GetPluginsEnvironment()
if pluginsEnvironment == nil {
return false, nil
}
availablePlugins, err := pluginsEnvironment.Available()
if err != nil {
return false, model.NewAppError("IsBotExemptFromDMRestrictions", "app.plugin.get_plugins.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
pluginIDs := make(map[string]bool, len(availablePlugins))
for _, plugin := range availablePlugins {
if plugin.Manifest != nil {
pluginIDs[plugin.Manifest.Id] = true
}
}
return pluginIDs[bot.OwnerId], nil
}
// UpdateBotActive marks a bot as active or inactive, along with its corresponding user.
func (a *App) UpdateBotActive(rctx request.CTX, botUserId string, active bool) (*model.Bot, *model.AppError) {
user, nErr := a.Srv().Store().User().Get(context.Background(), botUserId)
if nErr != nil {
var nfErr *store.ErrNotFound
switch {
case errors.As(nErr, &nfErr):
return nil, model.NewAppError("PatchBot", MissingAccountError, nil, "", http.StatusNotFound).Wrap(nErr)
default:
return nil, model.NewAppError("PatchBot", "app.user.get.app_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
if _, err := a.UpdateActive(rctx, user, active); err != nil {
return nil, err
}
bot, nErr := a.Srv().Store().Bot().Get(botUserId, true)
if nErr != nil {
var nfErr *store.ErrNotFound
switch {
case errors.As(nErr, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(nErr)
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("UpdateBotActive", "app.bot.getbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
changed := true
if active && bot.DeleteAt != 0 {
bot.DeleteAt = 0
} else if !active && bot.DeleteAt == 0 {
bot.DeleteAt = model.GetMillis()
} else {
changed = false
}
if changed {
bot, nErr = a.Srv().Store().Bot().Update(bot)
if nErr != nil {
var nfErr *store.ErrNotFound
var appErr *model.AppError
switch {
case errors.As(nErr, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(nErr)
case errors.As(nErr, &appErr): // in case we haven't converted to plain error.
return nil, appErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("PatchBot", "app.bot.patchbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
}
}
}
return bot, nil
}
// PermanentDeleteBot permanently deletes a bot and its corresponding user.
func (a *App) PermanentDeleteBot(rctx request.CTX, botUserId string) *model.AppError {
if err := a.Srv().Store().Bot().PermanentDelete(botUserId); err != nil {
var invErr *store.ErrInvalidInput
switch {
case errors.As(err, &invErr):
return model.NewAppError("PermanentDeleteBot", "app.bot.permenent_delete.bad_id", map[string]any{"user_id": invErr.Value}, "", http.StatusBadRequest).Wrap(err)
default: // last fallback in case it doesn't map to an existing app error.
return model.NewAppError("PatchBot", "app.bot.permanent_delete.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
}
if err := a.Srv().Store().User().PermanentDelete(rctx, botUserId); err != nil {
return model.NewAppError("PermanentDeleteBot", "app.user.permanent_delete.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
return nil
}
// UpdateBotOwner changes a bot's owner to the given value.
func (a *App) UpdateBotOwner(rctx request.CTX, botUserId, newOwnerId string) (*model.Bot, *model.AppError) {
bot, err := a.Srv().Store().Bot().Get(botUserId, true)
if err != nil {
var nfErr *store.ErrNotFound
switch {
case errors.As(err, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(err)
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("UpdateBotOwner", "app.bot.getbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
}
bot.OwnerId = newOwnerId
bot, err = a.Srv().Store().Bot().Update(bot)
if err != nil {
var nfErr *store.ErrNotFound
var appErr *model.AppError
switch {
case errors.As(err, &nfErr):
return nil, model.MakeBotNotFoundError("SqlBotStore.Get", nfErr.ID).Wrap(err)
case errors.As(err, &appErr): // in case we haven't converted to plain error.
return nil, appErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("PatchBot", "app.bot.patchbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
}
return bot, nil
}
// disableUserBots disables all bots owned by the given user.
func (a *App) disableUserBots(rctx request.CTX, userID string) *model.AppError {
perPage := 20
for {
options := &model.BotGetOptions{
OwnerId: userID,
IncludeDeleted: false,
OnlyOrphaned: false,
Page: 0,
PerPage: perPage,
}
userBots, err := a.GetBots(rctx, options)
if err != nil {
return err
}
for _, bot := range userBots {
_, err := a.UpdateBotActive(rctx, bot.UserId, false)
if err != nil {
rctx.Logger().Warn("Unable to deactivate bot.", mlog.String("bot_user_id", bot.UserId), mlog.Err(err))
}
}
// Get next set of bots if we got the max number of bots
if len(userBots) == perPage {
options.Page += 1
continue
}
break
}
return nil
}
func (a *App) notifySysadminsBotOwnerDeactivated(rctx request.CTX, userID string) *model.AppError {
perPage := 25
botOptions := &model.BotGetOptions{
OwnerId: userID,
IncludeDeleted: false,
OnlyOrphaned: false,
Page: 0,
PerPage: perPage,
}
// get owner bots
var userBots []*model.Bot
for {
bots, err := a.GetBots(rctx, botOptions)
if err != nil {
return err
}
userBots = append(userBots, bots...)
if len(bots) < perPage {
break
}
botOptions.Page += 1
}
// user does not own bots
if len(userBots) == 0 {
return nil
}
userOptions := &model.UserGetOptions{
Page: 0,
PerPage: perPage,
Role: model.SystemAdminRoleId,
Inactive: false,
}
// get sysadmins
var sysAdmins []*model.User
for {
sysAdminsList, err := a.GetUsersFromProfiles(userOptions)
if err != nil {
return err
}
sysAdmins = append(sysAdmins, sysAdminsList...)
if len(sysAdminsList) < perPage {
break
}
userOptions.Page += 1
}
// user being disabled
user, err := a.GetUser(userID)
if err != nil {
return err
}
// for each sysadmin, notify user that owns bots was disabled
for _, sysAdmin := range sysAdmins {
channel, appErr := a.GetOrCreateDirectChannel(rctx, sysAdmin.Id, sysAdmin.Id)
if appErr != nil {
return appErr
}
post := &model.Post{
UserId: sysAdmin.Id,
ChannelId: channel.Id,
Message: a.getDisableBotSysadminMessage(user, userBots),
Type: model.PostTypeSystemGeneric,
}
_, _, appErr = a.CreatePost(rctx, post, channel, model.CreatePostFlags{SetOnline: true})
if appErr != nil {
return appErr
}
}
return nil
}
func (a *App) getDisableBotSysadminMessage(user *model.User, userBots model.BotList) string {
disableBotsSetting := *a.Config().ServiceSettings.DisableBotsWhenOwnerIsDeactivated
var printAllBots = true
numBotsToPrint := len(userBots)
if numBotsToPrint > 10 {
numBotsToPrint = 10
printAllBots = false
}
var message, botList string
for _, bot := range userBots[:numBotsToPrint] {
botList += fmt.Sprintf("* %v\n", bot.Username)
}
T := i18n.GetUserTranslations(user.Locale)
message = T("app.bot.get_disable_bot_sysadmin_message",
map[string]any{
"UserName": user.Username,
"NumBots": len(userBots),
"BotNames": botList,
"disableBotsSetting": disableBotsSetting,
"printAllBots": printAllBots,
})
return message
}
// ConvertUserToBot converts a user to bot.
func (a *App) ConvertUserToBot(rctx request.CTX, user *model.User) (*model.Bot, *model.AppError) {
// Clear OAuth credentials before converting to bot
if user.AuthService != "" {
emptyString := ""
userAuth := &model.UserAuth{
AuthService: "",
AuthData: &emptyString,
}
_, err := a.UpdateUserAuth(rctx, user.Id, userAuth)
if err != nil {
return nil, err
}
// Refresh user data
updatedUser, err := a.GetUser(user.Id)
if err != nil {
return nil, err
}
user = updatedUser
}
bot, err := a.Srv().Store().Bot().Save(model.BotFromUser(user))
if err != nil {
var appErr *model.AppError
switch {
case errors.As(err, &appErr): // in case we haven't converted to plain error.
return nil, appErr
default: // last fallback in case it doesn't map to an existing app error.
return nil, model.NewAppError("CreateBot", "app.bot.createbot.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
}
}
if err := a.RevokeAllSessions(rctx, user.Id); err != nil {
return nil, err
}
a.InvalidateCacheForUser(user.Id)
return bot, nil
}