Git Sagar
829ca73b1b
Built-in DHCP (raw Ethernet frames through tunnel), automatic reconnection, host route management, classless static routes (option 121/249), DNS config. Single static binary, Linux only. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
137 lines
3.5 KiB
Go
137 lines
3.5 KiB
Go
// SHA-0 implementation for SoftEther VPN password authentication.
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//
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// SoftEther uses SHA-0 (the original, withdrawn FIPS-180 hash — NOT SHA-1) for
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// password hashing and the SecurePassword challenge-response. SHA-0 differs from
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// SHA-1 only in that the message schedule expansion does NOT include a left-rotate
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// by 1 bit (see transform() below).
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//
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// Auth flow:
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// 1. Client hashes the plaintext password: HashedPassword = SHA0(password)
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// 2. Server sends a 20-byte random challenge in the Hello pack
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// 3. Client computes: SecurePassword = SHA0(HashedPassword + ServerRandom)
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// 4. Client sends SecurePassword in the auth pack
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//
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// Reference C implementation:
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// https://github.com/SoftEtherVPN/SoftEtherVPN/blob/v5.02.5187/src/Mayaqua/Encrypt.c#L1088 (Sha0)
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// https://github.com/SoftEtherVPN/SoftEtherVPN/blob/v5.02.5187/src/Cedar/Sam.c#L105 (SecurePassword)
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package client
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const sha1Size = 20
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func rol(bits int, value uint32) uint32 {
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return (value << bits) | (value >> (32 - bits))
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}
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type sha0ctx struct {
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count uint64
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buf [64]byte
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state [8]uint32
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}
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func (c *sha0ctx) init() {
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c.state[0] = 0x67452301
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c.state[1] = 0xEFCDAB89
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c.state[2] = 0x98BADCFE
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c.state[3] = 0x10325476
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c.state[4] = 0xC3D2E1F0
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c.count = 0
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}
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func (c *sha0ctx) transform() {
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var W [80]uint32
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p := 0
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t := 0
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for ; t < 16; t++ {
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W[t] = uint32(c.buf[p])<<24 | uint32(c.buf[p+1])<<16 | uint32(c.buf[p+2])<<8 | uint32(c.buf[p+3])
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p += 4
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}
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// SHA-0: W[t] = W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16] (NO rotate)
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// SHA-1 would be: W[t] = rol(1, W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16])
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for ; t < 80; t++ {
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W[t] = W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]
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}
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A, B, C, D, E := c.state[0], c.state[1], c.state[2], c.state[3], c.state[4]
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for t = 0; t < 80; t++ {
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tmp := rol(5, A) + E + W[t]
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if t < 20 {
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tmp += (D ^ (B & (C ^ D))) + 0x5A827999
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} else if t < 40 {
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tmp += (B ^ C ^ D) + 0x6ED9EBA1
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} else if t < 60 {
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tmp += ((B & C) | (D & (B | C))) + 0x8F1BBCDC
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} else {
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tmp += (B ^ C ^ D) + 0xCA62C1D6
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}
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E = D
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D = C
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C = rol(30, B)
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B = A
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A = tmp
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}
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c.state[0] += A
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c.state[1] += B
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c.state[2] += C
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c.state[3] += D
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c.state[4] += E
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}
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func (c *sha0ctx) update(data []byte) {
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i := int(c.count & 63)
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c.count += uint64(len(data))
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for _, d := range data {
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c.buf[i] = d
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i++
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if i == 64 {
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c.transform()
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i = 0
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}
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}
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}
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func (c *sha0ctx) final() {
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cnt := c.count * 8
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c.update([]byte{0x80})
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for c.count&63 != 56 {
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c.update([]byte{0x0})
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}
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for i := 0; i < 8; i++ {
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c.update([]byte{byte(cnt >> ((7 - i) * 8))})
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}
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p := 0
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for i := 0; i < 5; i++ {
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c.buf[p] = byte(c.state[i] >> 24)
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c.buf[p+1] = byte(c.state[i] >> 16)
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c.buf[p+2] = byte(c.state[i] >> 8)
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c.buf[p+3] = byte(c.state[i])
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p += 4
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}
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}
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func sha0(data []byte) [sha1Size]byte {
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var c sha0ctx
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c.init()
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c.update(data)
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c.final()
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var out [sha1Size]byte
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copy(out[:], c.buf[:sha1Size])
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return out
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}
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// SecurePassword computes the challenge-response: SHA0(HashedPassword + ServerRandom).
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// See: https://github.com/SoftEtherVPN/SoftEtherVPN/blob/v5.02.5187/src/Cedar/Sam.c#L105
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func SecurePassword(hashedPassword, random [sha1Size]byte) [sha1Size]byte {
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buf := make([]byte, sha1Size*2)
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copy(buf, hashedPassword[:])
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copy(buf[sha1Size:], random[:])
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return sha0(buf)
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}
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// HashPassword computes SHA0(password) — the first step of SoftEther password auth.
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// The result is what SoftEther stores server-side as "HashedPassword".
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// See: https://github.com/SoftEtherVPN/SoftEtherVPN/blob/v5.02.5187/src/Cedar/Sam.c#L91 (HashPassword)
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func HashPassword(password string) [sha1Size]byte {
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return sha0([]byte(password))
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}
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