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2f98197857
This fork golang.org/x/crypto/ssh (at upstream x/crypto git rev e47973b1c1) into tailscale.com/tempfork/sshtest/ssh so we can hack up the client in weird ways to simulate other SSH clients seen in the wild. Two changes were made to the files when they were copied from x/crypto: * internal/poly1305 imports were replaced by the non-internal version; no code changes otherwise. It didn't need the internal one. * all decode-with-passphrase funcs were deleted, to avoid using the internal package x/crypto/ssh/internal/bcrypt_pbkdf Then the tests passed. Updates #14969 Change-Id: Ibf1abebfe608c75fef4da0255314f65e54ce5077 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
98 lines
2.1 KiB
Go
98 lines
2.1 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ssh
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import (
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"io"
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"sync"
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)
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// buffer provides a linked list buffer for data exchange
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// between producer and consumer. Theoretically the buffer is
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// of unlimited capacity as it does no allocation of its own.
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type buffer struct {
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// protects concurrent access to head, tail and closed
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*sync.Cond
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head *element // the buffer that will be read first
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tail *element // the buffer that will be read last
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closed bool
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}
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// An element represents a single link in a linked list.
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type element struct {
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buf []byte
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next *element
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}
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// newBuffer returns an empty buffer that is not closed.
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func newBuffer() *buffer {
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e := new(element)
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b := &buffer{
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Cond: newCond(),
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head: e,
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tail: e,
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}
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return b
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}
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// write makes buf available for Read to receive.
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// buf must not be modified after the call to write.
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func (b *buffer) write(buf []byte) {
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b.Cond.L.Lock()
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e := &element{buf: buf}
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b.tail.next = e
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b.tail = e
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b.Cond.Signal()
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b.Cond.L.Unlock()
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}
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// eof closes the buffer. Reads from the buffer once all
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// the data has been consumed will receive io.EOF.
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func (b *buffer) eof() {
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b.Cond.L.Lock()
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b.closed = true
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b.Cond.Signal()
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b.Cond.L.Unlock()
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}
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// Read reads data from the internal buffer in buf. Reads will block
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// if no data is available, or until the buffer is closed.
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func (b *buffer) Read(buf []byte) (n int, err error) {
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b.Cond.L.Lock()
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defer b.Cond.L.Unlock()
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for len(buf) > 0 {
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// if there is data in b.head, copy it
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if len(b.head.buf) > 0 {
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r := copy(buf, b.head.buf)
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buf, b.head.buf = buf[r:], b.head.buf[r:]
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n += r
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continue
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}
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// if there is a next buffer, make it the head
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if len(b.head.buf) == 0 && b.head != b.tail {
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b.head = b.head.next
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continue
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}
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// if at least one byte has been copied, return
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if n > 0 {
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break
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}
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// if nothing was read, and there is nothing outstanding
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// check to see if the buffer is closed.
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if b.closed {
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err = io.EOF
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break
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}
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// out of buffers, wait for producer
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b.Cond.Wait()
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}
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return
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}
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