diff options
Diffstat (limited to 'usr.bin/ssh/nchan.c')
| -rw-r--r-- | usr.bin/ssh/nchan.c | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/usr.bin/ssh/nchan.c b/usr.bin/ssh/nchan.c new file mode 100644 index 00000000000..257eb79717a --- /dev/null +++ b/usr.bin/ssh/nchan.c @@ -0,0 +1,547 @@ +/* + * Copyright (c) 1999 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" +RCSID("$OpenBSD: nchan.c,v 1.28 2001/05/31 10:30:16 markus Exp $"); + +#include "ssh1.h" +#include "ssh2.h" +#include "buffer.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 + */ +/* events concerning the INPUT from socket for channel (istate) */ +chan_event_fn *chan_rcvd_oclose = NULL; +chan_event_fn *chan_read_failed = NULL; +chan_event_fn *chan_ibuf_empty = NULL; +/* events concerning the OUTPUT from channel for socket (ostate) */ +chan_event_fn *chan_rcvd_ieof = NULL; +chan_event_fn *chan_write_failed = NULL; +chan_event_fn *chan_obuf_empty = NULL; +/* + * ACTIONS: should never update the channel states + */ +static void chan_send_ieof1(Channel *c); +static void chan_send_oclose1(Channel *c); +static void chan_send_close2(Channel *c); +static void chan_send_eof2(Channel *c); + +/* helper */ +static void chan_shutdown_write(Channel *c); +static void chan_shutdown_read(Channel *c); + +/* + * SSH1 specific implementation of event functions + */ + +static void +chan_rcvd_oclose1(Channel *c) +{ + debug("channel %d: rcvd oclose", c->self); + switch (c->istate) { + case CHAN_INPUT_WAIT_OCLOSE: + debug("channel %d: input wait_oclose -> closed", c->self); + c->istate = CHAN_INPUT_CLOSED; + break; + case CHAN_INPUT_OPEN: + debug("channel %d: input open -> closed", c->self); + chan_shutdown_read(c); + chan_send_ieof1(c); + c->istate = CHAN_INPUT_CLOSED; + break; + case CHAN_INPUT_WAIT_DRAIN: + /* both local read_failed and remote write_failed */ + log("channel %d: input drain -> closed", c->self); + chan_send_ieof1(c); + c->istate = CHAN_INPUT_CLOSED; + break; + default: + error("channel %d: protocol error: rcvd_oclose for istate %d", + c->self, c->istate); + return; + } +} +static void +chan_read_failed_12(Channel *c) +{ + debug("channel %d: read failed", c->self); + switch (c->istate) { + case CHAN_INPUT_OPEN: + debug("channel %d: input open -> drain", c->self); + chan_shutdown_read(c); + c->istate = CHAN_INPUT_WAIT_DRAIN; +#if 0 + if (buffer_len(&c->input) == 0) { + debug("channel %d: input: no drain shortcut", c->self); + chan_ibuf_empty(c); + } +#endif + break; + default: + error("channel %d: chan_read_failed for istate %d", + c->self, c->istate); + break; + } +} +static void +chan_ibuf_empty1(Channel *c) +{ + debug("channel %d: ibuf empty", c->self); + if (buffer_len(&c->input)) { + error("channel %d: chan_ibuf_empty for non empty buffer", + c->self); + return; + } + switch (c->istate) { + case CHAN_INPUT_WAIT_DRAIN: + debug("channel %d: input drain -> wait_oclose", c->self); + chan_send_ieof1(c); + c->istate = CHAN_INPUT_WAIT_OCLOSE; + break; + default: + error("channel %d: chan_ibuf_empty for istate %d", + c->self, c->istate); + break; + } +} +static void +chan_rcvd_ieof1(Channel *c) +{ + debug("channel %d: rcvd ieof", c->self); + if (c->type != SSH_CHANNEL_OPEN) { + debug("channel %d: non-open", c->self); + if (c->istate == CHAN_INPUT_OPEN) { + debug("channel %d: non-open: input open -> wait_oclose", + c->self); + chan_shutdown_read(c); + chan_send_ieof1(c); + c->istate = CHAN_INPUT_WAIT_OCLOSE; + } else { + error("channel %d: non-open: istate %d != open", + c->self, c->istate); + } + if (c->ostate == CHAN_OUTPUT_OPEN) { + debug("channel %d: non-open: output open -> closed", + c->self); + chan_send_oclose1(c); + c->ostate = CHAN_OUTPUT_CLOSED; + } else { + error("channel %d: non-open: ostate %d != open", + c->self, c->ostate); + } + return; + } + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + debug("channel %d: output open -> drain", c->self); + c->ostate = CHAN_OUTPUT_WAIT_DRAIN; + break; + case CHAN_OUTPUT_WAIT_IEOF: + debug("channel %d: output wait_ieof -> closed", c->self); + c->ostate = CHAN_OUTPUT_CLOSED; + break; + default: + error("channel %d: protocol error: rcvd_ieof for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_write_failed1(Channel *c) +{ + debug("channel %d: write failed", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + debug("channel %d: output open -> wait_ieof", c->self); + chan_send_oclose1(c); + c->ostate = CHAN_OUTPUT_WAIT_IEOF; + break; + case CHAN_OUTPUT_WAIT_DRAIN: + debug("channel %d: output wait_drain -> closed", c->self); + chan_send_oclose1(c); + c->ostate = CHAN_OUTPUT_CLOSED; + break; + default: + error("channel %d: chan_write_failed for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_obuf_empty1(Channel *c) +{ + debug("channel %d: obuf empty", c->self); + if (buffer_len(&c->output)) { + error("channel %d: chan_obuf_empty for non empty buffer", + c->self); + return; + } + switch (c->ostate) { + case CHAN_OUTPUT_WAIT_DRAIN: + debug("channel %d: output drain -> closed", c->self); + chan_send_oclose1(c); + c->ostate = CHAN_OUTPUT_CLOSED; + break; + default: + error("channel %d: internal error: obuf_empty for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_send_ieof1(Channel *c) +{ + debug("channel %d: send ieof", c->self); + switch (c->istate) { + case CHAN_INPUT_OPEN: + case CHAN_INPUT_WAIT_DRAIN: + packet_start(SSH_MSG_CHANNEL_INPUT_EOF); + packet_put_int(c->remote_id); + packet_send(); + break; + default: + error("channel %d: cannot send ieof for istate %d", + c->self, c->istate); + break; + } +} +static void +chan_send_oclose1(Channel *c) +{ + debug("channel %d: send oclose", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + case CHAN_OUTPUT_WAIT_DRAIN: + chan_shutdown_write(c); + buffer_consume(&c->output, buffer_len(&c->output)); + packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + break; + default: + error("channel %d: cannot send oclose for ostate %d", + c->self, c->ostate); + break; + } +} + +/* + * the same for SSH2 + */ +static void +chan_rcvd_oclose2(Channel *c) +{ + debug("channel %d: rcvd close", c->self); + 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 */ + c->ostate = CHAN_OUTPUT_CLOSED; + c->istate = 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 + */ + debug("channel %d: output open -> drain", c->self); + c->ostate = CHAN_OUTPUT_WAIT_DRAIN; + break; + } + switch (c->istate) { + case CHAN_INPUT_OPEN: + debug("channel %d: input open -> closed", c->self); + chan_shutdown_read(c); + break; + case CHAN_INPUT_WAIT_DRAIN: + debug("channel %d: input drain -> closed", c->self); + chan_send_eof2(c); + break; + } + c->istate = CHAN_INPUT_CLOSED; +} +static void +chan_ibuf_empty2(Channel *c) +{ + debug("channel %d: ibuf empty", c->self); + if (buffer_len(&c->input)) { + error("channel %d: chan_ibuf_empty for non empty buffer", + c->self); + return; + } + switch (c->istate) { + case CHAN_INPUT_WAIT_DRAIN: + debug("channel %d: input drain -> closed", c->self); + if (!(c->flags & CHAN_CLOSE_SENT)) + chan_send_eof2(c); + c->istate = CHAN_INPUT_CLOSED; + break; + default: + error("channel %d: chan_ibuf_empty for istate %d", + c->self, c->istate); + break; + } +} +static void +chan_rcvd_ieof2(Channel *c) +{ + debug("channel %d: rcvd eof", c->self); + if (c->ostate == CHAN_OUTPUT_OPEN) { + debug("channel %d: output open -> drain", c->self); + c->ostate = CHAN_OUTPUT_WAIT_DRAIN; + } +} +static void +chan_write_failed2(Channel *c) +{ + debug("channel %d: write failed", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + debug("channel %d: output open -> closed", c->self); + chan_shutdown_write(c); /* ?? */ + c->ostate = CHAN_OUTPUT_CLOSED; + break; + case CHAN_OUTPUT_WAIT_DRAIN: + debug("channel %d: output drain -> closed", c->self); + chan_shutdown_write(c); + c->ostate = CHAN_OUTPUT_CLOSED; + break; + default: + error("channel %d: chan_write_failed for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_obuf_empty2(Channel *c) +{ + debug("channel %d: obuf empty", c->self); + if (buffer_len(&c->output)) { + error("channel %d: chan_obuf_empty for non empty buffer", + c->self); + return; + } + switch (c->ostate) { + case CHAN_OUTPUT_WAIT_DRAIN: + debug("channel %d: output drain -> closed", c->self); + chan_shutdown_write(c); + c->ostate = CHAN_OUTPUT_CLOSED; + break; + default: + error("channel %d: chan_obuf_empty for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_send_eof2(Channel *c) +{ + debug("channel %d: send eof", c->self); + switch (c->istate) { + case CHAN_INPUT_WAIT_DRAIN: + packet_start(SSH2_MSG_CHANNEL_EOF); + packet_put_int(c->remote_id); + packet_send(); + break; + default: + error("channel %d: cannot send eof for istate %d", + c->self, c->istate); + break; + } +} +static void +chan_send_close2(Channel *c) +{ + debug("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 { + packet_start(SSH2_MSG_CHANNEL_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + c->flags |= CHAN_CLOSE_SENT; + } +} + +/* shared */ + +void +chan_mark_dead(Channel *c) +{ + c->type = SSH_CHANNEL_ZOMBIE; +} + +int +chan_is_dead(Channel *c) +{ + if (c->type == SSH_CHANNEL_ZOMBIE) { + debug("channel %d: zombie", c->self); + return 1; + } + if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) + return 0; + if (!compat20) { + debug("channel %d: is dead", c->self); + return 1; + } + /* + * we have to delay the close message if the efd (for stderr) is + * still active + */ + if (((c->extended_usage != CHAN_EXTENDED_IGNORE) && + buffer_len(&c->extended) > 0) +#if 0 + || ((c->extended_usage == CHAN_EXTENDED_READ) && + c->efd != -1) +#endif + ) { + debug2("channel %d: active efd: %d len %d type %s", + c->self, c->efd, buffer_len(&c->extended), + c->extended_usage==CHAN_EXTENDED_READ ? + "read": "write"); + } else { + if (!(c->flags & CHAN_CLOSE_SENT)) { + chan_send_close2(c); + } + if ((c->flags & CHAN_CLOSE_SENT) && + (c->flags & CHAN_CLOSE_RCVD)) { + debug("channel %d: is dead", c->self); + return 1; + } + } + return 0; +} + +void +chan_init_iostates(Channel *c) +{ + c->ostate = CHAN_OUTPUT_OPEN; + c->istate = CHAN_INPUT_OPEN; + c->flags = 0; +} + +/* init */ +void +chan_init(void) +{ + if (compat20) { + chan_rcvd_oclose = chan_rcvd_oclose2; + chan_read_failed = chan_read_failed_12; + chan_ibuf_empty = chan_ibuf_empty2; + + chan_rcvd_ieof = chan_rcvd_ieof2; + chan_write_failed = chan_write_failed2; + chan_obuf_empty = chan_obuf_empty2; + } else { + chan_rcvd_oclose = chan_rcvd_oclose1; + chan_read_failed = chan_read_failed_12; + chan_ibuf_empty = chan_ibuf_empty1; + + chan_rcvd_ieof = chan_rcvd_ieof1; + chan_write_failed = chan_write_failed1; + chan_obuf_empty = chan_obuf_empty1; + } +} + +/* helper */ +static void +chan_shutdown_write(Channel *c) +{ + buffer_consume(&c->output, buffer_len(&c->output)); + if (compat20 && c->type == SSH_CHANNEL_LARVAL) + return; + /* shutdown failure is allowed if write failed already */ + debug("channel %d: close_write", c->self); + if (c->sock != -1) { + if (shutdown(c->sock, SHUT_WR) < 0) + debug("channel %d: chan_shutdown_write: " + "shutdown() failed for fd%d: %.100s", + c->self, c->sock, strerror(errno)); + } else { + if (close(c->wfd) < 0) + log("channel %d: chan_shutdown_write: " + "close() failed for fd%d: %.100s", + c->self, c->wfd, strerror(errno)); + c->wfd = -1; + } +} +static void +chan_shutdown_read(Channel *c) +{ + if (compat20 && c->type == SSH_CHANNEL_LARVAL) + return; + debug("channel %d: close_read", c->self); + if (c->sock != -1) { + if (shutdown(c->sock, SHUT_RD) < 0) + error("channel %d: chan_shutdown_read: " + "shutdown() failed for fd%d [i%d o%d]: %.100s", + c->self, c->sock, c->istate, c->ostate, + strerror(errno)); + } else { + if (close(c->rfd) < 0) + log("channel %d: chan_shutdown_read: " + "close() failed for fd%d: %.100s", + c->self, c->rfd, strerror(errno)); + c->rfd = -1; + } +} |