71 lines
1.2 KiB
Go
71 lines
1.2 KiB
Go
package sshd
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import "encoding/binary"
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// Helpers below are borrowed from go.crypto circa 2011:
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// parsePtyRequest parses the payload of the pty-req message and extracts the
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// dimensions of the terminal. See RFC 4254, section 6.2.
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func parsePtyRequest(s []byte) (width, height int, ok bool) {
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_, s, ok = parseString(s)
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if !ok {
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return
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}
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width32, s, ok := parseUint32(s)
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if !ok {
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return
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}
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height32, _, ok := parseUint32(s)
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width = int(width32)
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height = int(height32)
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if width < 1 {
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ok = false
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}
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if height < 1 {
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ok = false
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}
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return
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}
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func parseWinchRequest(s []byte) (width, height int, ok bool) {
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width32, _, ok := parseUint32(s)
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if !ok {
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return
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}
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height32, _, ok := parseUint32(s)
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if !ok {
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return
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}
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width = int(width32)
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height = int(height32)
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if width < 1 {
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ok = false
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}
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if height < 1 {
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ok = false
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}
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return
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}
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func parseString(in []byte) (out string, rest []byte, ok bool) {
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if len(in) < 4 {
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return
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}
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length := binary.BigEndian.Uint32(in)
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if uint32(len(in)) < 4+length {
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return
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}
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out = string(in[4 : 4+length])
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rest = in[4+length:]
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ok = true
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return
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}
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func parseUint32(in []byte) (uint32, []byte, bool) {
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if len(in) < 4 {
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return 0, nil, false
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}
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return binary.BigEndian.Uint32(in), in[4:], true
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}
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