Adding upstream version 1:9.6p1.upstream/1%9.6p1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 443 insertions, 0 deletions

diff --git a/nchan.c b/nchan.c
new file mode 100644
index 0000000..d33426f
--- /dev/null
+++ b/nchan.c
@@ -0,0 +1,443 @@
+/* $OpenBSD: nchan.c,v 1.74 2022/02/01 23:32:51 djm Exp $ */
+/*
+ * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <errno.h>
+#include <string.h>
+#include <stdarg.h>
+
+#include "openbsd-compat/sys-queue.h"
+#include "ssh2.h"
+#include "sshbuf.h"
+#include "ssherr.h"
+#include "packet.h"
+#include "channels.h"
+#include "compat.h"
+#include "log.h"
+
+/*
+ * SSH Protocol 1.5 aka New Channel Protocol
+ * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
+ * Written by Markus Friedl in October 1999
+ *
+ * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
+ * tear down of channels:
+ *
+ * 1.3:	strict request-ack-protocol:
+ *	CLOSE	->
+ *		<-  CLOSE_CONFIRM
+ *
+ * 1.5:	uses variations of:
+ *	IEOF	->
+ *		<-  OCLOSE
+ *		<-  IEOF
+ *	OCLOSE	->
+ *	i.e. both sides have to close the channel
+ *
+ * 2.0: the EOF messages are optional
+ *
+ * See the debugging output from 'ssh -v' and 'sshd -d' of
+ * ssh-1.2.27 as an example.
+ *
+ */
+
+/* functions manipulating channel states */
+/*
+ * EVENTS update channel input/output states execute ACTIONS
+ */
+/*
+ * ACTIONS: should never update the channel states
+ */
+static void	chan_send_eof2(struct ssh *, Channel *);
+static void	chan_send_eow2(struct ssh *, Channel *);
+
+/* helper */
+static void	chan_shutdown_write(struct ssh *, Channel *);
+static void	chan_shutdown_read(struct ssh *, Channel *);
+static void	chan_shutdown_extended_read(struct ssh *, Channel *);
+
+static const char * const ostates[] = {
+	"open", "drain", "wait_ieof", "closed",
+};
+static const char * const istates[] = {
+	"open", "drain", "wait_oclose", "closed",
+};
+
+static void
+chan_set_istate(Channel *c, u_int next)
+{
+	if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
+		fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
+	debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
+	    istates[next]);
+	c->istate = next;
+}
+
+static void
+chan_set_ostate(Channel *c, u_int next)
+{
+	if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
+		fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
+	debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
+	    ostates[next]);
+	c->ostate = next;
+}
+
+void
+chan_read_failed(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: read failed", c->self);
+	switch (c->istate) {
+	case CHAN_INPUT_OPEN:
+		chan_shutdown_read(ssh, c);
+		chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
+		break;
+	default:
+		error("channel %d: chan_read_failed for istate %d",
+		    c->self, c->istate);
+		break;
+	}
+}
+
+void
+chan_ibuf_empty(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: ibuf empty", c->self);
+	if (sshbuf_len(c->input)) {
+		error("channel %d: chan_ibuf_empty for non empty buffer",
+		    c->self);
+		return;
+	}
+	switch (c->istate) {
+	case CHAN_INPUT_WAIT_DRAIN:
+		if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_LOCAL)))
+			chan_send_eof2(ssh, c);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
+		break;
+	default:
+		error("channel %d: chan_ibuf_empty for istate %d",
+		    c->self, c->istate);
+		break;
+	}
+}
+
+void
+chan_obuf_empty(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: obuf empty", c->self);
+	if (sshbuf_len(c->output)) {
+		error("channel %d: chan_obuf_empty for non empty buffer",
+		    c->self);
+		return;
+	}
+	switch (c->ostate) {
+	case CHAN_OUTPUT_WAIT_DRAIN:
+		chan_shutdown_write(ssh, c);
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
+		break;
+	default:
+		error("channel %d: internal error: obuf_empty for ostate %d",
+		    c->self, c->ostate);
+		break;
+	}
+}
+
+void
+chan_rcvd_eow(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: rcvd eow", c->self);
+	switch (c->istate) {
+	case CHAN_INPUT_OPEN:
+		chan_shutdown_read(ssh, c);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
+		break;
+	}
+}
+
+static void
+chan_send_eof2(struct ssh *ssh, Channel *c)
+{
+	int r;
+
+	debug2("channel %d: send eof", c->self);
+	switch (c->istate) {
+	case CHAN_INPUT_WAIT_DRAIN:
+		if (!c->have_remote_id)
+			fatal_f("channel %d: no remote_id", c->self);
+		if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EOF)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal_fr(r, "send CHANNEL_EOF");
+		c->flags |= CHAN_EOF_SENT;
+		break;
+	default:
+		error("channel %d: cannot send eof for istate %d",
+		    c->self, c->istate);
+		break;
+	}
+}
+
+static void
+chan_send_close2(struct ssh *ssh, Channel *c)
+{
+	int r;
+
+	debug2("channel %d: send close", c->self);
+	if (c->ostate != CHAN_OUTPUT_CLOSED ||
+	    c->istate != CHAN_INPUT_CLOSED) {
+		error("channel %d: cannot send close for istate/ostate %d/%d",
+		    c->self, c->istate, c->ostate);
+	} else if (c->flags & CHAN_CLOSE_SENT) {
+		error("channel %d: already sent close", c->self);
+	} else {
+		if (!c->have_remote_id)
+			fatal_f("channel %d: no remote_id", c->self);
+		if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_CLOSE)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal_fr(r, "send CHANNEL_EOF");
+		c->flags |= CHAN_CLOSE_SENT;
+	}
+}
+
+static void
+chan_send_eow2(struct ssh *ssh, Channel *c)
+{
+	int r;
+
+	debug2("channel %d: send eow", c->self);
+	if (c->ostate == CHAN_OUTPUT_CLOSED) {
+		error("channel %d: must not sent eow on closed output",
+		    c->self);
+		return;
+	}
+	if (!(ssh->compat & SSH_NEW_OPENSSH))
+		return;
+	if (!c->have_remote_id)
+		fatal_f("channel %d: no remote_id", c->self);
+	if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "eow@openssh.com")) != 0 ||
+	    (r = sshpkt_put_u8(ssh, 0)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		fatal_fr(r, "send CHANNEL_EOF");
+}
+
+/* shared */
+
+void
+chan_rcvd_ieof(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: rcvd eof", c->self);
+	c->flags |= CHAN_EOF_RCVD;
+	if (c->ostate == CHAN_OUTPUT_OPEN)
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
+	if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
+	    sshbuf_len(c->output) == 0 &&
+	    !CHANNEL_EFD_OUTPUT_ACTIVE(c))
+		chan_obuf_empty(ssh, c);
+}
+
+void
+chan_rcvd_oclose(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: rcvd close", c->self);
+	if (!(c->flags & CHAN_LOCAL)) {
+		if (c->flags & CHAN_CLOSE_RCVD)
+			error("channel %d: protocol error: close rcvd twice",
+			    c->self);
+		c->flags |= CHAN_CLOSE_RCVD;
+	}
+	if (c->type == SSH_CHANNEL_LARVAL) {
+		/* tear down larval channels immediately */
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
+		return;
+	}
+	switch (c->ostate) {
+	case CHAN_OUTPUT_OPEN:
+		/*
+		 * wait until a data from the channel is consumed if a CLOSE
+		 * is received
+		 */
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
+		break;
+	}
+	switch (c->istate) {
+	case CHAN_INPUT_OPEN:
+		chan_shutdown_read(ssh, c);
+		chan_shutdown_extended_read(ssh, c);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
+		break;
+	case CHAN_INPUT_WAIT_DRAIN:
+		if (!(c->flags & CHAN_LOCAL))
+			chan_send_eof2(ssh, c);
+		chan_shutdown_extended_read(ssh, c);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
+		break;
+	}
+}
+
+void
+chan_write_failed(struct ssh *ssh, Channel *c)
+{
+	debug2("channel %d: write failed", c->self);
+	switch (c->ostate) {
+	case CHAN_OUTPUT_OPEN:
+	case CHAN_OUTPUT_WAIT_DRAIN:
+		chan_shutdown_write(ssh, c);
+		if (strcmp(c->ctype, "session") == 0)
+			chan_send_eow2(ssh, c);
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
+		break;
+	default:
+		error("channel %d: chan_write_failed for ostate %d",
+		    c->self, c->ostate);
+		break;
+	}
+}
+
+void
+chan_mark_dead(struct ssh *ssh, Channel *c)
+{
+	c->type = SSH_CHANNEL_ZOMBIE;
+}
+
+int
+chan_is_dead(struct ssh *ssh, Channel *c, int do_send)
+{
+	if (c->type == SSH_CHANNEL_ZOMBIE) {
+		debug2("channel %d: zombie", c->self);
+		return 1;
+	}
+	if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
+		return 0;
+	if ((ssh->compat & SSH_BUG_EXTEOF) &&
+	    c->extended_usage == CHAN_EXTENDED_WRITE &&
+	    c->efd != -1 &&
+	    sshbuf_len(c->extended) > 0) {
+		debug2("channel %d: active efd: %d len %zu",
+		    c->self, c->efd, sshbuf_len(c->extended));
+		return 0;
+	}
+	if (c->flags & CHAN_LOCAL) {
+		debug2("channel %d: is dead (local)", c->self);
+		return 1;
+	}		
+	if (!(c->flags & CHAN_CLOSE_SENT)) {
+		if (do_send) {
+			chan_send_close2(ssh, c);
+		} else {
+			/* channel would be dead if we sent a close */
+			if (c->flags & CHAN_CLOSE_RCVD) {
+				debug2("channel %d: almost dead",
+				    c->self);
+				return 1;
+			}
+		}
+	}
+	if ((c->flags & CHAN_CLOSE_SENT) &&
+	    (c->flags & CHAN_CLOSE_RCVD)) {
+		debug2("channel %d: is dead", c->self);
+		return 1;
+	}
+	return 0;
+}
+
+/* helper */
+static void
+chan_shutdown_write(struct ssh *ssh, Channel *c)
+{
+	sshbuf_reset(c->output);
+	if (c->type == SSH_CHANNEL_LARVAL)
+		return;
+	/* shutdown failure is allowed if write failed already */
+	debug2_f("channel %d: (i%d o%d sock %d wfd %d efd %d [%s])",
+	    c->self, c->istate, c->ostate, c->sock, c->wfd, c->efd,
+	    channel_format_extended_usage(c));
+	if (c->sock != -1) {
+		if (shutdown(c->sock, SHUT_WR) == -1) {
+			debug2_f("channel %d: shutdown() failed for "
+			    "fd %d [i%d o%d]: %.100s", c->self, c->sock,
+			    c->istate, c->ostate, strerror(errno));
+		}
+	} else {
+		if (channel_close_fd(ssh, c, &c->wfd) < 0) {
+			logit_f("channel %d: close() failed for "
+			    "fd %d [i%d o%d]: %.100s", c->self, c->wfd,
+			    c->istate, c->ostate, strerror(errno));
+		}
+	}
+}
+
+static void
+chan_shutdown_read(struct ssh *ssh, Channel *c)
+{
+	if (c->type == SSH_CHANNEL_LARVAL)
+		return;
+	debug2_f("channel %d: (i%d o%d sock %d wfd %d efd %d [%s])",
+	    c->self, c->istate, c->ostate, c->sock, c->rfd, c->efd,
+	    channel_format_extended_usage(c));
+	if (c->sock != -1) {
+		/*
+		 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
+		 * write side has been closed already. (bug on Linux)
+		 * HP-UX may return ENOTCONN also.
+		 */
+		if (shutdown(c->sock, SHUT_RD) == -1 && errno != ENOTCONN) {
+			error_f("channel %d: shutdown() failed for "
+			    "fd %d [i%d o%d]: %.100s", c->self, c->sock,
+			    c->istate, c->ostate, strerror(errno));
+		}
+	} else {
+		if (channel_close_fd(ssh, c, &c->rfd) < 0) {
+			logit_f("channel %d: close() failed for "
+			    "fd %d [i%d o%d]: %.100s", c->self, c->rfd,
+			    c->istate, c->ostate, strerror(errno));
+		}
+	}
+}
+
+static void
+chan_shutdown_extended_read(struct ssh *ssh, Channel *c)
+{
+	if (c->type == SSH_CHANNEL_LARVAL || c->efd == -1)
+		return;
+	if (c->extended_usage != CHAN_EXTENDED_READ &&
+	    c->extended_usage != CHAN_EXTENDED_IGNORE)
+		return;
+	debug_f("channel %d: (i%d o%d sock %d wfd %d efd %d [%s])",
+	    c->self, c->istate, c->ostate, c->sock, c->rfd, c->efd,
+	    channel_format_extended_usage(c));
+	if (channel_close_fd(ssh, c, &c->efd) < 0) {
+		logit_f("channel %d: close() failed for "
+		    "extended fd %d [i%d o%d]: %.100s", c->self, c->efd,
+		    c->istate, c->ostate, strerror(errno));
+	}
+}