tyler.durden
/
openssh-portable
mirror of https://github.com/PowerShell/openssh-portable.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

upstream: Add server support for signalling sessions via the SSH 

channel/ session protocol. Signalling is only supported to sesssions that are
not subsystems and were not started with a forced command.

Long requested in bz#1424

Based on a patch from markus@ and reworked by dtucker@;
ok markus@ dtucker@

OpenBSD-Commit-ID: 4bea826f575862eaac569c4bedd1056a268be1c3
This commit is contained in:
djm@openbsd.org 2018-10-02 12:40:07 +00:00 committed by Damien Miller
parent dba5025833
commit cd98925c64
2 changed files with 77 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
session.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: session.c,v 1.305 2018/07/25 13:56:23 deraadt Exp $ */
/* $OpenBSD: session.c,v 1.306 2018/10/02 12:40:07 djm Exp $ */
/*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
@ -705,7 +705,9 @@ do_exec(struct ssh *ssh, Session *s, const char *command)
command = auth_opts->force_command;
forced = "(key-option)";
}
s->forced = 0;
if (forced != NULL) {
s->forced = 1;
if (IS_INTERNAL_SFTP(command)) {
s->is_subsystem = s->is_subsystem ?
SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
@ -2101,6 +2103,76 @@ session_env_req(struct ssh *ssh, Session *s)
return (0);
}
/*
* Conversion of signals from ssh channel request names.
* Subset of signals from RFC 4254 section 6.10C, with SIGINFO as
* local extension.
*/
static int
name2sig(char *name)
{
#define SSH_SIG(x) if (strcmp(name, #x) == 0) return SIG ## x
SSH_SIG(HUP);
SSH_SIG(INT);
SSH_SIG(KILL);
SSH_SIG(QUIT);
SSH_SIG(TERM);
SSH_SIG(USR1);
SSH_SIG(USR2);
#undef SSH_SIG
if (strcmp(name, "INFO@openssh.com") == 0)
return SIGINFO;
return -1;
}
static int
session_signal_req(struct ssh *ssh, Session *s)
{
char *signame = NULL;
int r, sig, success = 0;
if ((r = sshpkt_get_cstring(ssh, &signame, NULL)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0) {
error("%s: parse packet: %s", __func__, ssh_err(r));
goto out;
}
if ((sig = name2sig(signame)) == -1) {
error("%s: unsupported signal \"%s\"", __func__, signame);
goto out;
}
if (s->pid <= 0) {
error("%s: no pid for session %d", __func__, s->self);
goto out;
}
if (s->forced || s->is_subsystem) {
error("%s: refusing to send signal %s to %s session", __func__,
signame, s->forced ? "forced-command" : "subsystem");
goto out;
}
if (!use_privsep || mm_is_monitor()) {
error("%s: session signalling requires privilege separation",
__func__);
goto out;
}
debug("%s: signal %s, killpg(%ld, %d)", __func__, signame,
(long)s->pid, sig);
temporarily_use_uid(s->pw);
r = killpg(s->pid, sig);
restore_uid();
if (r != 0) {
error("%s: killpg(%ld, %d): %s", __func__, (long)s->pid,
sig, strerror(errno));
goto out;
}
/* success */
success = 1;
out:
free(signame);
return success;
}
static int
session_auth_agent_req(struct ssh *ssh, Session *s)
{
@ -2157,6 +2229,8 @@ session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype)
success = session_window_change_req(ssh, s);
} else if (strcmp(rtype, "break") == 0) {
success = session_break_req(ssh, s);
} else if (strcmp(rtype, "signal") == 0) {
success = session_signal_req(ssh, s);
}
return success;

3
session.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: session.h,v 1.35 2017/09/12 06:32:07 djm Exp $ */
/* $OpenBSD: session.h,v 1.36 2018/10/02 12:40:07 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
@ -35,6 +35,7 @@ struct Session {
struct passwd *pw;
Authctxt *authctxt;
pid_t pid;
int forced;
/* tty */
char *term;