45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
package auth
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import (
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"context"
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"crypto/rand"
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"encoding/base64"
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"github.com/mediocregopher/radix/v4"
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)
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// numStates is the number of CSRF states stored in Redis at any one time.
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// This must be an integer.
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const numStates = "1000"
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// setCSRFState generates a random string to use as state, then stores that in Redis.
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func (s *Server) setCSRFState(ctx context.Context) (string, error) {
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state := RandBase64(32)
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err := s.DB.MultiCmd(ctx,
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radix.Cmd(nil, "LPUSH", "csrf", state),
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radix.Cmd(nil, "LTRIM", "csrf", "0", numStates),
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)
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return state, err
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}
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// validateCSRFState checks if the given state exists in Redis.
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func (s *Server) validateCSRFState(ctx context.Context, state string) (matched bool, err error) {
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var num int
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err = s.DB.Redis.Do(ctx, radix.Cmd(&num, "LREM", "csrf", "1", state))
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if err != nil {
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return
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}
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return num > 0, nil
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}
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// RandBase64 returns a string of random bytes encoded in raw base 64.
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func RandBase64(size int) string {
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b := make([]byte, size)
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_, err := rand.Read(b)
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if err != nil {
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panic(err)
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}
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return base64.RawURLEncoding.EncodeToString(b)
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}
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