diff options
Diffstat (limited to 'crypto/openssh/nchan.c')
| -rw-r--r-- | crypto/openssh/nchan.c | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/crypto/openssh/nchan.c b/crypto/openssh/nchan.c new file mode 100644 index 0000000..ad461f4 --- /dev/null +++ b/crypto/openssh/nchan.c @@ -0,0 +1,490 @@ +/* $OpenBSD: nchan.c,v 1.57 2006/08/03 03:34:42 deraadt 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 "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 + */ +/* + * ACTIONS: should never update the channel states + */ +static void chan_send_ieof1(Channel *); +static void chan_send_oclose1(Channel *); +static void chan_send_close2(Channel *); +static void chan_send_eof2(Channel *); + +/* helper */ +static void chan_shutdown_write(Channel *); +static void chan_shutdown_read(Channel *); + +static char *ostates[] = { "open", "drain", "wait_ieof", "closed" }; +static char *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; +} + +/* + * SSH1 specific implementation of event functions + */ + +static void +chan_rcvd_oclose1(Channel *c) +{ + debug2("channel %d: rcvd oclose", c->self); + switch (c->istate) { + case CHAN_INPUT_WAIT_OCLOSE: + chan_set_istate(c, CHAN_INPUT_CLOSED); + break; + case CHAN_INPUT_OPEN: + chan_shutdown_read(c); + chan_send_ieof1(c); + chan_set_istate(c, CHAN_INPUT_CLOSED); + break; + case CHAN_INPUT_WAIT_DRAIN: + /* both local read_failed and remote write_failed */ + chan_send_ieof1(c); + chan_set_istate(c, CHAN_INPUT_CLOSED); + break; + default: + error("channel %d: protocol error: rcvd_oclose for istate %d", + c->self, c->istate); + return; + } +} +void +chan_read_failed(Channel *c) +{ + debug2("channel %d: read failed", c->self); + switch (c->istate) { + case CHAN_INPUT_OPEN: + chan_shutdown_read(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(Channel *c) +{ + debug2("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: + if (compat20) { + if (!(c->flags & CHAN_CLOSE_SENT)) + chan_send_eof2(c); + chan_set_istate(c, CHAN_INPUT_CLOSED); + } else { + chan_send_ieof1(c); + chan_set_istate(c, 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) +{ + debug2("channel %d: rcvd ieof", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); + break; + case CHAN_OUTPUT_WAIT_IEOF: + chan_set_ostate(c, 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) +{ + debug2("channel %d: write failed", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + chan_shutdown_write(c); + chan_send_oclose1(c); + chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF); + break; + case CHAN_OUTPUT_WAIT_DRAIN: + chan_shutdown_write(c); + chan_send_oclose1(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_obuf_empty(Channel *c) +{ + debug2("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: + chan_shutdown_write(c); + if (!compat20) + chan_send_oclose1(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; + } +} +static void +chan_send_ieof1(Channel *c) +{ + debug2("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) +{ + debug2("channel %d: send oclose", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + case CHAN_OUTPUT_WAIT_DRAIN: + buffer_clear(&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_close2(Channel *c) +{ + debug2("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 */ + 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(c); + chan_set_istate(c, CHAN_INPUT_CLOSED); + break; + case CHAN_INPUT_WAIT_DRAIN: + chan_send_eof2(c); + chan_set_istate(c, CHAN_INPUT_CLOSED); + break; + } +} +static void +chan_rcvd_eof2(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); +} +static void +chan_write_failed2(Channel *c) +{ + debug2("channel %d: write failed", c->self); + switch (c->ostate) { + case CHAN_OUTPUT_OPEN: + case CHAN_OUTPUT_WAIT_DRAIN: + chan_shutdown_write(c); + chan_set_ostate(c, CHAN_OUTPUT_CLOSED); + break; + default: + error("channel %d: chan_write_failed for ostate %d", + c->self, c->ostate); + break; + } +} +static void +chan_send_eof2(Channel *c) +{ + debug2("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(); + 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(Channel *c) +{ + 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 { + packet_start(SSH2_MSG_CHANNEL_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + c->flags |= CHAN_CLOSE_SENT; + } +} + +/* shared */ + +void +chan_rcvd_ieof(Channel *c) +{ + if (compat20) + chan_rcvd_eof2(c); + else + chan_rcvd_ieof1(c); + if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN && + buffer_len(&c->output) == 0 && + !CHANNEL_EFD_OUTPUT_ACTIVE(c)) + chan_obuf_empty(c); +} +void +chan_rcvd_oclose(Channel *c) +{ + if (compat20) + chan_rcvd_close2(c); + else + chan_rcvd_oclose1(c); +} +void +chan_write_failed(Channel *c) +{ + if (compat20) + chan_write_failed2(c); + else + chan_write_failed1(c); +} + +void +chan_mark_dead(Channel *c) +{ + c->type = SSH_CHANNEL_ZOMBIE; +} + +int +chan_is_dead(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 (!compat20) { + debug2("channel %d: is dead", c->self); + return 1; + } + if ((datafellows & SSH_BUG_EXTEOF) && + c->extended_usage == CHAN_EXTENDED_WRITE && + c->efd != -1 && + buffer_len(&c->extended) > 0) { + debug2("channel %d: active efd: %d len %d", + c->self, c->efd, buffer_len(&c->extended)); + return 0; + } + if (!(c->flags & CHAN_CLOSE_SENT)) { + if (do_send) { + chan_send_close2(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(Channel *c) +{ + buffer_clear(&c->output); + if (compat20 && c->type == SSH_CHANNEL_LARVAL) + return; + /* shutdown failure is allowed if write failed already */ + debug2("channel %d: close_write", c->self); + if (c->sock != -1) { + if (shutdown(c->sock, SHUT_WR) < 0) + debug2("channel %d: chan_shutdown_write: " + "shutdown() failed for fd%d: %.100s", + c->self, c->sock, strerror(errno)); + } else { + if (channel_close_fd(&c->wfd) < 0) + logit("channel %d: chan_shutdown_write: " + "close() failed for fd%d: %.100s", + c->self, c->wfd, strerror(errno)); + } +} +static void +chan_shutdown_read(Channel *c) +{ + if (compat20 && c->type == SSH_CHANNEL_LARVAL) + return; + debug2("channel %d: close_read", c->self); + 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) < 0 + && errno != ENOTCONN) + 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 (channel_close_fd(&c->rfd) < 0) + logit("channel %d: chan_shutdown_read: " + "close() failed for fd%d: %.100s", + c->self, c->rfd, strerror(errno)); + } +} |
