132 lines
3.6 KiB
Go
132 lines
3.6 KiB
Go
package server
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import (
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"crypto/rand"
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"crypto/subtle"
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"errors"
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"fmt"
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"math/big"
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"strings"
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"time"
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"github.com/go-redis/redis"
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)
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func (r *RedisRouter) StoreInvitation(invitation []byte, timeout int, password string, serverTimeout int, urlLen int) (string, time.Time, error) {
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id, err := r.createShortId(urlLen)
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if err != nil {
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return "", time.Time{}, fmt.Errorf("failed to create invitation ID: %w", err)
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}
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if timeout > serverTimeout {
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timeout = serverTimeout
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}
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r.Client.Set("mwiv:"+id, invitation, 0) //, time.Duration(timeout*1000000))
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if len(password) > 0 {
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r.Client.Set("mwpw:"+id, password, 0) //, time.Duration(timeout*1000000))
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}
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return id, time.Now().Add(time.Duration(timeout * 1000000)).UTC(), nil
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}
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func (r *RedisRouter) GetInvitation(id string, password string) ([]byte, error) {
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// Check failed attempts counter
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failedAttemptsKey := "mwfa:" + id
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failedAttempts := 0 // Default when key doesn't exist
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val, err := r.Client.Get(failedAttemptsKey).Int()
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if err == nil {
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failedAttempts = val
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} else if err != redis.Nil {
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return nil, fmt.Errorf("failed to check attempts: %w", err)
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}
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// If err == redis.Nil, key doesn't exist, so failedAttempts stays 0
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// If already hit the limit, delete invitation and fail
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if failedAttempts >= 3 {
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r.deleteInvitation(id)
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return nil, errors.New("invitation locked due to too many failed attempts")
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}
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// Check if password is required
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passRequired := false
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expectedpass, err := r.Client.Get("mwpw:" + id).Result()
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if err != nil {
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passRequired = false
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} else {
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passRequired = true
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}
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// Validate password with constant-time comparison
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if passRequired {
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if subtle.ConstantTimeCompare([]byte(password), []byte(expectedpass)) != 1 {
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// Increment failed attempts
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newCount := failedAttempts + 1
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r.Client.Set(failedAttemptsKey, newCount, 0)
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// If this was the 3rd attempt, delete invitation
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if newCount >= 3 {
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r.deleteInvitation(id)
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return nil, errors.New("auth failed - invitation destroyed after 3 attempts")
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}
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return nil, errors.New("auth failed")
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}
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}
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// Success - get invitation data
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mwiv, err := r.Client.Get("mwiv:" + id).Result()
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if err != nil {
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return nil, err
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}
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// Clear failed attempts counter on successful access
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r.Client.Del(failedAttemptsKey)
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return []byte(mwiv), nil
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}
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// deleteInvitation removes all invitation-related keys from Redis
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func (r *RedisRouter) deleteInvitation(id string) {
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r.Client.Del("mwiv:" + id) // invitation data
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r.Client.Del("mwpw:" + id) // password
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r.Client.Del("mwfa:" + id) // failed attempts
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r.Client.Del("mwan:" + id) // answer to invitation
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}
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func (r *RedisRouter) StoreAnswerToInvitation(id string, timeout int, invitation []byte, serverTimeout int) time.Time {
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if timeout > serverTimeout {
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timeout = serverTimeout
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}
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r.Client.Set("mwan:"+id, invitation, time.Duration(timeout*1000000))
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return time.Now().Add(time.Duration(timeout * 1000000)).UTC()
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}
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func (r *RedisRouter) GetAnswerToInvitation(id string) ([]byte, error) {
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mwan, err := r.Client.Get("mwan:" + id).Result()
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if err != nil {
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return nil, err
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}
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return []byte(mwan), nil
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}
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func (r *RedisRouter) createShortId(length int) (string, error) {
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alphabet := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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alphabetLen := big.NewInt(int64(len(alphabet)))
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// for not in redis
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for {
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var id strings.Builder
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id.Grow(length)
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for i := 0; i < length; i++ {
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n, err := rand.Int(rand.Reader, alphabetLen)
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if err != nil {
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return "", fmt.Errorf("random generation failed: %w", err)
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}
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id.WriteByte(alphabet[n.Int64()])
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}
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idStr := id.String()
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if r.Client.Get("mwiv:"+idStr).Err() == redis.Nil {
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return idStr, nil
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}
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}
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}
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