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https://github.com/netbirdio/netbird.git
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1aa1f915a2
Extract the dial-then-handshake sequence into nbssh.Handshake, which applies the context deadline to the socket for the duration of the handshake. Previously only the Android client did this; the CLI, wasm and SSH proxy paths could block forever on a peer that accepts the TCP connection and then goes silent, since ClientConfig.Timeout is not used by NewClientConn.
46 lines
1.4 KiB
Go
46 lines
1.4 KiB
Go
package ssh
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import (
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"context"
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"fmt"
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"io"
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"net"
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"time"
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log "github.com/sirupsen/logrus"
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"golang.org/x/crypto/ssh"
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)
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// Handshake runs the SSH client handshake on an already dialed conn and
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// returns the resulting client. Dialing bounds only the TCP establishment;
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// without a deadline on the socket a peer that accepts and then goes silent
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// blocks the handshake forever, so the context deadline is applied to conn
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// for the duration of the handshake. conn is closed on any error.
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func Handshake(ctx context.Context, conn net.Conn, addr string, config *ssh.ClientConfig) (*ssh.Client, error) {
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if deadline, ok := ctx.Deadline(); ok {
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if err := conn.SetDeadline(deadline); err != nil {
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closeHandshake(conn, "conn after deadline error")
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return nil, fmt.Errorf("set handshake deadline: %w", err)
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}
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}
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sshConn, chans, reqs, err := ssh.NewClientConn(conn, addr, config)
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if err != nil {
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closeHandshake(conn, "conn after handshake error")
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return nil, fmt.Errorf("ssh handshake: %w", err)
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}
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if err := conn.SetDeadline(time.Time{}); err != nil {
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closeHandshake(sshConn, "ssh conn after deadline clear error")
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return nil, fmt.Errorf("clear handshake deadline: %w", err)
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}
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return ssh.NewClient(sshConn, chans, reqs), nil
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}
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func closeHandshake(c io.Closer, label string) {
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if err := c.Close(); err != nil {
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log.Debugf("ssh: close %s: %v", label, err)
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}
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}
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