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Add dbclient '-J &fd' option for a file descriptor

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Based on patch by Harald Becker
This commit is contained in:
Matt Johnston 2018-02-18 15:12:15 +08:00
parent 802dace05e
commit 1656db9e58
2 changed files with 26 additions and 0 deletions
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15
cli-main.c
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@ -158,6 +158,21 @@ static void cli_proxy_cmd(int *sock_in, int *sock_out, pid_t *pid_out) {
size_t ex_cmdlen; size_t ex_cmdlen;
int ret; int ret;
/* File descriptor "-j &3" */
if (*cli_opts.proxycmd == '&') {
char *p = cli_opts.proxycmd + 1;
int sock = strtoul(p, &p, 10);
/* must be a single number, and not stdin/stdout/stderr */
if (sock > 2 && sock < 1024 && *p == '\0') {
*sock_in = sock;
*sock_out = sock;
return;
}
}
/* Normal proxycommand */
/* So that spawn_command knows which shell to run */
fill_passwd(cli_opts.own_user); fill_passwd(cli_opts.own_user);
ex_cmdlen = strlen(cli_opts.proxycmd) + 6; /* "exec " + command + '\0' */ ex_cmdlen = strlen(cli_opts.proxycmd) + 6; /* "exec " + command + '\0' */

11
dbclient.1
View File

@ -111,11 +111,22 @@ if 0 disables keepalives. If no response is received for 3 consecutive keepalive
.B \-I \fIidle_timeout .B \-I \fIidle_timeout
Disconnect the session if no traffic is transmitted or received for \fIidle_timeout\fR seconds. Disconnect the session if no traffic is transmitted or received for \fIidle_timeout\fR seconds.
.TP .TP
.\" TODO: how to avoid a line break between these two -J arguments?
.B \-J \fIproxy_command .B \-J \fIproxy_command
.TP
.B \-J \fI&fd
.br
Use the standard input/output of the program \fIproxy_command\fR rather than using Use the standard input/output of the program \fIproxy_command\fR rather than using
a normal TCP connection. A hostname should be still be provided, as this is used for a normal TCP connection. A hostname should be still be provided, as this is used for
comparing saved hostkeys. This command will be executed as "exec proxy_command ..." with the comparing saved hostkeys. This command will be executed as "exec proxy_command ..." with the
default shell. default shell.
The second form &fd will make dbclient use the numeric file descriptor as a socket. This
can be used for more complex tunnelling scenarios. Example usage with socat is
socat EXEC:'dbclient -J &38 ev',fdin=38,fdout=38 TCP4:host.example.com:22
.TP .TP
.B \-B \fIendhost:endport .B \-B \fIendhost:endport
"Netcat-alike" mode, where Dropbear will connect to the given host, then create a "Netcat-alike" mode, where Dropbear will connect to the given host, then create a