104 lines
2.7 KiB
Go
104 lines
2.7 KiB
Go
// SPDX-License-Identifier: MIT
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// SPDX-FileCopyrightText: © 2015 LabStack LLC and Echo contributors
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package middleware
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import (
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"bufio"
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"crypto/rand"
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"io"
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"strings"
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"sync"
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)
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func matchScheme(domain, pattern string) bool {
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didx := strings.Index(domain, ":")
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pidx := strings.Index(pattern, ":")
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return didx != -1 && pidx != -1 && domain[:didx] == pattern[:pidx]
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}
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// matchSubdomain compares authority with wildcard
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func matchSubdomain(domain, pattern string) bool {
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if !matchScheme(domain, pattern) {
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return false
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}
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didx := strings.Index(domain, "://")
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pidx := strings.Index(pattern, "://")
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if didx == -1 || pidx == -1 {
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return false
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}
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domAuth := domain[didx+3:]
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// to avoid long loop by invalid long domain
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if len(domAuth) > 253 {
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return false
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}
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patAuth := pattern[pidx+3:]
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domComp := strings.Split(domAuth, ".")
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patComp := strings.Split(patAuth, ".")
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for i := len(domComp)/2 - 1; i >= 0; i-- {
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opp := len(domComp) - 1 - i
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domComp[i], domComp[opp] = domComp[opp], domComp[i]
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}
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for i := len(patComp)/2 - 1; i >= 0; i-- {
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opp := len(patComp) - 1 - i
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patComp[i], patComp[opp] = patComp[opp], patComp[i]
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}
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for i, v := range domComp {
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if len(patComp) <= i {
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return false
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}
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p := patComp[i]
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if p == "*" {
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return true
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}
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if p != v {
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return false
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}
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}
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return false
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}
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// https://tip.golang.org/doc/go1.19#:~:text=Read%20no%20longer%20buffers%20random%20data%20obtained%20from%20the%20operating%20system%20between%20calls
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var randomReaderPool = sync.Pool{New: func() interface{} {
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return bufio.NewReader(rand.Reader)
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}}
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const randomStringCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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const randomStringCharsetLen = 52 // len(randomStringCharset)
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const randomStringMaxByte = 255 - (256 % randomStringCharsetLen)
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func randomString(length uint8) string {
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reader := randomReaderPool.Get().(*bufio.Reader)
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defer randomReaderPool.Put(reader)
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b := make([]byte, length)
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r := make([]byte, length+(length/4)) // perf: avoid read from rand.Reader many times
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var i uint8 = 0
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// security note:
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// we can't just simply do b[i]=randomStringCharset[rb%len(randomStringCharset)],
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// len(len(randomStringCharset)) is 52, and rb is [0, 255], 256 = 52 * 4 + 48.
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// make the first 48 characters more possibly to be generated then others.
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// So we have to skip bytes when rb > randomStringMaxByte
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for {
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_, err := io.ReadFull(reader, r)
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if err != nil {
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panic("unexpected error happened when reading from bufio.NewReader(crypto/rand.Reader)")
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}
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for _, rb := range r {
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if rb > randomStringMaxByte {
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// Skip this number to avoid bias.
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continue
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}
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b[i] = randomStringCharset[rb%randomStringCharsetLen]
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i++
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if i == length {
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return string(b)
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}
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}
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}
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}
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