diff options
| -rw-r--r-- | usr.bin/ssh/session.c | 76 | ||||
| -rw-r--r-- | usr.bin/ssh/session.h | 3 |
2 files changed, 77 insertions, 2 deletions
diff --git a/usr.bin/ssh/session.c b/usr.bin/ssh/session.c index 420f0819497..0b1d8b02b58 100644 --- a/usr.bin/ssh/session.c +++ b/usr.bin/ssh/session.c @@ -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 @@ -641,7 +641,9 @@ 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; @@ -1756,6 +1758,76 @@ 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) { @@ -1812,6 +1884,8 @@ 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; diff --git a/usr.bin/ssh/session.h b/usr.bin/ssh/session.h index 54dd1f0ca08..ce59dabd906 100644 --- a/usr.bin/ssh/session.h +++ b/usr.bin/ssh/session.h @@ -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; |