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propagate from branch 'au.asn.ucc.matt.dropbear' (head 924b731b50d4147eed8e9382c98a2573259a6cad)

Browse Source 
to branch 'au.asn.ucc.matt.dropbear.channel-fix' (head e73ee8f7ae404a9355685c30828a0ad4524031bc)

--HG--
branch : channel-fix
extra : convert_revision : be0d837816e2e985c7b2d80614d5df3496028e94
This commit is contained in:
Matt Johnston 2007-02-11 09:55:00 +00:00
commit 674b4d013d
7 changed files with 285 additions and 272 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
channel.h
View File

@ -73,10 +73,9 @@ struct Channel {
circbuffer *extrabuf; /* extended-data for the program - used like writebuf
but for stderr */
int sentclosed, recvclosed;
/* this is set when we receive/send a channel eof packet */
int recveof, senteof;
/* whether close/eof messages have been exchanged */
int sent_close, recv_close;
int recv_eof, sent_eof;
int initconn; /* used for TCP forwarding, whether the channel has been
fully initialised */
@ -85,6 +84,8 @@ struct Channel {
for this channel (and are awaiting a confirmation
or failure). */
int flushing;
const struct ChanType* type;
};
@ -94,7 +95,7 @@ struct ChanType {
int sepfds; /* Whether this channel has seperate pipes for in/out or not */
char *name;
int (*inithandler)(struct Channel*);
int (*checkclose)(struct Channel*);
int (*check_close)(struct Channel*);
void (*reqhandler)(struct Channel*);
void (*closehandler)(struct Channel*);

3
cli-channel.c
View File

@ -39,9 +39,6 @@ void recv_msg_channel_extended_data() {
TRACE(("enter recv_msg_channel_extended_data"))
channel = getchannel();
if (channel == NULL) {
dropbear_exit("Unknown channel");
}
if (channel->type != &clichansess) {
TRACE(("leave recv_msg_channel_extended_data: chantype is wrong"))

467
common-channel.c
View File

@ -43,22 +43,22 @@ static void send_msg_channel_open_confirmation(struct Channel* channel,
static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf);
static void send_msg_channel_window_adjust(struct Channel *channel,
unsigned int incr);
static void send_msg_channel_data(struct Channel *channel, int isextended,
unsigned int exttype);
static void send_msg_channel_data(struct Channel *channel, int isextended);
static void send_msg_channel_eof(struct Channel *channel);
static void send_msg_channel_close(struct Channel *channel);
static void removechannel(struct Channel *channel);
static void deletechannel(struct Channel *channel);
static void checkinitdone(struct Channel *channel);
static void checkclose(struct Channel *channel);
static void closewritefd(struct Channel * channel);
static void closereadfd(struct Channel * channel, int fd);
static void closechanfd(struct Channel *channel, int fd, int how);
static void remove_channel(struct Channel *channel);
static void delete_channel(struct Channel *channel);
static void check_in_progress(struct Channel *channel);
static unsigned int write_pending(struct Channel * channel);
static void check_close(struct Channel *channel);
static void close_chan_fd(struct Channel *channel, int fd, int how);
#define FD_UNINIT (-2)
#define FD_CLOSED (-1)
#define ERRFD_IS_READ(channel) ((channel)->extrabuf == NULL)
#define ERRFD_IS_WRITE(channel) (!ERRFD_IS_READ(channel))
/* Initialise all the channels */
void chaninitialise(const struct ChanType *chantypes[]) {
@ -85,7 +85,7 @@ void chancleanup() {
for (i = 0; i < ses.chansize; i++) {
if (ses.channels[i] != NULL) {
TRACE(("channel %d closing", i))
removechannel(ses.channels[i]);
remove_channel(ses.channels[i]);
}
}
m_free(ses.channels);
@ -135,8 +135,8 @@ struct Channel* newchannel(unsigned int remotechan,
newchan = (struct Channel*)m_malloc(sizeof(struct Channel));
newchan->type = type;
newchan->index = i;
newchan->sentclosed = newchan->recvclosed = 0;
newchan->senteof = newchan->recveof = 0;
newchan->sent_close = newchan->recv_close = 0;
newchan->sent_eof = newchan->recv_eof = 0;
newchan->remotechan = remotechan;
newchan->transwindow = transwindow;
@ -148,6 +148,7 @@ struct Channel* newchannel(unsigned int remotechan,
newchan->errfd = FD_CLOSED; /* this isn't always set to start with */
newchan->initconn = 0;
newchan->await_open = 0;
newchan->flushing = 0;
newchan->writebuf = cbuf_new(RECV_MAXWINDOW);
newchan->extrabuf = NULL; /* The user code can set it up */
@ -164,25 +165,35 @@ struct Channel* newchannel(unsigned int remotechan,
}
/* Returns the channel structure corresponding to the channel in the current
* data packet (ses.payload must be positioned appropriately) */
struct Channel* getchannel() {
* data packet (ses.payload must be positioned appropriately).
* A valid channel is always returns, it will fail fatally with an unknown
* channel */
static struct Channel* getchannel_msg(const char* kind) {
unsigned int chan;
chan = buf_getint(ses.payload);
if (chan >= ses.chansize || ses.channels[chan] == NULL) {
return NULL;
if (kind) {
dropbear_exit("%s for unknown channel %d", kind, chan);
} else {
dropbear_exit("Unknown channel %d", chan);
}
}
return ses.channels[chan];
}
struct Channel* getchannel() {
return getchannel_msg(NULL);
}
/* Iterate through the channels, performing IO if available */
void channelio(fd_set *readfds, fd_set *writefds) {
struct Channel *channel;
unsigned int i;
/* iterate through all the possible channels */
/* foreach channel */
for (i = 0; i < ses.chansize; i++) {
channel = ses.channels[i];
@ -193,35 +204,38 @@ void channelio(fd_set *readfds, fd_set *writefds) {
/* read data and send it over the wire */
if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) {
send_msg_channel_data(channel, 0, 0);
TRACE(("send normal readfd"))
send_msg_channel_data(channel, 0);
}
/* read stderr data and send it over the wire */
if (channel->extrabuf == NULL &&
channel->errfd >= 0 && FD_ISSET(channel->errfd, readfds)) {
send_msg_channel_data(channel, 1, SSH_EXTENDED_DATA_STDERR);
if (ERRFD_IS_READ(channel) && channel->errfd >= 0
&& FD_ISSET(channel->errfd, readfds)) {
TRACE(("send normal errfd"))
send_msg_channel_data(channel, 1);
}
/* write to program/pipe stdin */
if (channel->writefd >= 0 && FD_ISSET(channel->writefd, writefds)) {
if (channel->initconn) {
checkinitdone(channel);
/* XXX should this go somewhere cleaner? */
check_in_progress(channel);
continue; /* Important not to use the channel after
checkinitdone(), as it may be NULL */
check_in_progress(), as it may be NULL */
}
writechannel(channel, channel->writefd, channel->writebuf);
}
/* stderr for client mode */
if (channel->extrabuf != NULL
if (ERRFD_IS_WRITE(channel)
&& channel->errfd >= 0 && FD_ISSET(channel->errfd, writefds)) {
writechannel(channel, channel->errfd, channel->extrabuf);
}
/* now handle any of the channel-closing type stuff */
checkclose(channel);
/* handle any channel closing etc */
check_close(channel);
} /* foreach channel */
}
/* Listeners such as TCP, X11, agent-auth */
#ifdef USING_LISTENERS
@ -230,94 +244,113 @@ void channelio(fd_set *readfds, fd_set *writefds) {
}
/* do all the EOF/close type stuff checking for a channel */
static void checkclose(struct Channel *channel) {
/* Returns true if there is data remaining to be written to stdin or
* stderr of a channel's endpoint. */
static unsigned int write_pending(struct Channel * channel) {
TRACE(("checkclose: writefd %d, readfd %d, errfd %d, sentclosed %d, recvclosed %d",
if (channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0) {
return 1;
} else if (channel->errfd >= 0 && channel->extrabuf &&
cbuf_getused(channel->extrabuf) > 0) {
return 1;
}
return 0;
}
/* EOF/close handling */
static void check_close(struct Channel *channel) {
TRACE(("check_close: writefd %d, readfd %d, errfd %d, sent_close %d, recv_close %d",
channel->writefd, channel->readfd,
channel->errfd, channel->sentclosed, channel->recvclosed))
TRACE(("writebuf size %d extrabuf ptr 0x%x extrabuf size %d",
channel->errfd, channel->sent_close, channel->recv_close))
TRACE(("writebuf size %d extrabuf size %d",
cbuf_getused(channel->writebuf),
channel->writebuf,
channel->writebuf ? 0 : cbuf_getused(channel->extrabuf)))
channel->extrabuf ? cbuf_getused(channel->extrabuf) : 0))
if (!channel->sentclosed) {
/* check for exited - currently only used for server sessions,
* if the shell has exited etc */
if (channel->type->checkclose) {
if (channel->type->checkclose(channel)) {
closewritefd(channel);
}
}
if (!channel->senteof
&& channel->readfd == FD_CLOSED
&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
send_msg_channel_eof(channel);
}
if (channel->writefd == FD_CLOSED
&& channel->readfd == FD_CLOSED
&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
send_msg_channel_close(channel);
}
if (!channel->flushing && channel->type->check_close
&& channel->type->check_close(channel))
{
channel->flushing = 1;
}
/* When either party wishes to terminate the channel, it sends
* SSH_MSG_CHANNEL_CLOSE. Upon receiving this message, a party MUST
* send back a SSH_MSG_CHANNEL_CLOSE unless it has already sent this
* message for the channel. The channel is considered closed for a
* party when it has both sent and received SSH_MSG_CHANNEL_CLOSE, and
* the party may then reuse the channel number. A party MAY send
* SSH_MSG_CHANNEL_CLOSE without having sent or received
* SSH_MSG_CHANNEL_EOF.
* (from draft-ietf-secsh-connect)
*/
if (channel->recvclosed) {
if (! channel->sentclosed) {
if (channel->recv_close && !write_pending(channel)) {
if (!channel->sent_close) {
TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
send_msg_channel_close(channel);
}
removechannel(channel);
remove_channel(channel);
return;
}
if (channel->recv_eof && !write_pending(channel)) {
close_chan_fd(channel, channel->writefd, SHUT_WR);
}
/* Special handling for flushing read data after an exit. We
read regardless of whether the select FD was set,
and if there isn't data available, the channel will get closed. */
if (channel->flushing) {
TRACE(("might send data, flushing"))
if (channel->readfd >= 0 && channel->transwindow > 0) {
TRACE(("send data readfd"))
send_msg_channel_data(channel, 0);
}
if (ERRFD_IS_READ(channel) && channel->readfd >= 0
&& channel->transwindow > 0) {
TRACE(("send data errfd"))
send_msg_channel_data(channel, 1);
}
}
/* If we're not going to send any more data, send EOF */
if (!channel->sent_eof
&& channel->readfd == FD_CLOSED
&& (ERRFD_IS_WRITE(channel) || channel->errfd == FD_CLOSED)) {
send_msg_channel_eof(channel);
}
/* And if we can't receive any more data from them either, close up */
if (!channel->sent_close
&& channel->readfd == FD_CLOSED
&& !write_pending(channel)) {
TRACE(("sending close, readfd is closed"))
send_msg_channel_close(channel);
}
}
/* Check whether a deferred (EINPROGRESS) connect() was successful, and
* if so, set up the channel properly. Otherwise, the channel is cleaned up, so
* it is important that the channel reference isn't used after a call to this
* function */
static void checkinitdone(struct Channel *channel) {
static void check_in_progress(struct Channel *channel) {
int val;
socklen_t vallen = sizeof(val);
TRACE(("enter checkinitdone"))
TRACE(("enter check_in_progress"))
if (getsockopt(channel->writefd, SOL_SOCKET, SO_ERROR, &val, &vallen)
|| val != 0) {
send_msg_channel_open_failure(channel->remotechan,
SSH_OPEN_CONNECT_FAILED, "", "");
close(channel->writefd);
deletechannel(channel);
TRACE(("leave checkinitdone: fail"))
delete_channel(channel);
TRACE(("leave check_in_progress: fail"))
} else {
send_msg_channel_open_confirmation(channel, channel->recvwindow,
channel->recvmaxpacket);
channel->readfd = channel->writefd;
channel->initconn = 0;
TRACE(("leave checkinitdone: success"))
TRACE(("leave check_in_progress: success"))
}
}
/* Send the close message and set the channel as closed */
static void send_msg_channel_close(struct Channel *channel) {
TRACE(("enter send_msg_channel_close"))
/* XXX server */
if (channel->type->closehandler) {
channel->type->closehandler(channel);
}
@ -329,8 +362,11 @@ static void send_msg_channel_close(struct Channel *channel) {
encrypt_packet();
channel->senteof = 1;
channel->sentclosed = 1;
channel->sent_eof = 1;
channel->sent_close = 1;
close_chan_fd(channel, channel->readfd, SHUT_RD);
close_chan_fd(channel, channel->errfd, SHUT_RDWR);
close_chan_fd(channel, channel->writefd, SHUT_WR);
TRACE(("leave send_msg_channel_close"))
}
@ -345,7 +381,7 @@ static void send_msg_channel_eof(struct Channel *channel) {
encrypt_packet();
channel->senteof = 1;
channel->sent_eof = 1;
TRACE(("leave send_msg_channel_eof"))
}
@ -357,32 +393,25 @@ static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf) {
int len, maxlen;
TRACE(("enter writechannel"))
TRACE(("enter writechannel fd %d", fd))
maxlen = cbuf_readlen(cbuf);
/* Write the data out */
len = write(fd, cbuf_readptr(cbuf, maxlen), maxlen);
if (len <= 0) {
TRACE(("errno %d len %d", errno, len))
if (len < 0 && errno != EINTR) {
/* no more to write - we close it even if the fd was stderr, since
* that's a nasty failure too */
closewritefd(channel);
close_chan_fd(channel, fd, SHUT_WR);
}
TRACE(("leave writechannel: len <= 0"))
return;
}
TRACE(("writechannel wrote %d", len))
cbuf_incrread(cbuf, len);
channel->recvdonelen += len;
if (fd == channel->writefd && cbuf_getused(cbuf) == 0 && channel->recveof) {
/* Check if we're closing up */
closewritefd(channel);
TRACE(("leave writechannel: recveof set"))
return;
}
/* Window adjust handling */
if (channel->recvdonelen >= RECV_WINDOWEXTEND) {
/* Set it back to max window */
@ -396,7 +425,6 @@ static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf) {
dropbear_assert(channel->extrabuf == NULL ||
channel->recvwindow <= cbuf_getavail(channel->extrabuf));
TRACE(("leave writechannel"))
}
@ -421,7 +449,7 @@ void setchannelfds(fd_set *readfds, fd_set *writefds) {
FD_SET(channel->readfd, readfds);
}
if (channel->extrabuf == NULL && channel->errfd >= 0) {
if (ERRFD_IS_READ(channel) && channel->errfd >= 0) {
FD_SET(channel->errfd, readfds);
}
}
@ -429,11 +457,10 @@ void setchannelfds(fd_set *readfds, fd_set *writefds) {
/* Stuff from the wire */
if ((channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0 )
|| channel->initconn) {
FD_SET(channel->writefd, writefds);
}
if (channel->extrabuf != NULL && channel->errfd >= 0
if (ERRFD_IS_WRITE(channel) != NULL && channel->errfd >= 0
&& cbuf_getused(channel->extrabuf) > 0 ) {
FD_SET(channel->errfd, writefds);
}
@ -455,18 +482,11 @@ void recv_msg_channel_eof() {
TRACE(("enter recv_msg_channel_eof"))
channel = getchannel();
if (channel == NULL) {
dropbear_exit("EOF for unknown channel");
}
channel = getchannel_msg("EOF");
channel->recveof = 1;
if (cbuf_getused(channel->writebuf) == 0
&& (channel->extrabuf == NULL
|| cbuf_getused(channel->extrabuf) == 0)) {
closewritefd(channel);
}
channel->recv_eof = 1;
check_close(channel);
TRACE(("leave recv_msg_channel_eof"))
}
@ -478,27 +498,20 @@ void recv_msg_channel_close() {
TRACE(("enter recv_msg_channel_close"))
channel = getchannel();
if (channel == NULL) {
/* disconnect ? */
dropbear_exit("Close for unknown channel");
}
channel = getchannel_msg("Close");
channel->recveof = 1;
channel->recvclosed = 1;
if (channel->sentclosed) {
removechannel(channel);
}
channel->recv_eof = 1;
channel->recv_close = 1;
check_close(channel);
TRACE(("leave recv_msg_channel_close"))
}
/* Remove a channel entry, this is only executed after both sides have sent
* channel close */
static void removechannel(struct Channel * channel) {
static void remove_channel(struct Channel * channel) {
TRACE(("enter removechannel"))
TRACE(("enter remove_channel"))
TRACE(("channel index is %d", channel->index))
cbuf_free(channel->writebuf);
@ -511,20 +524,23 @@ static void removechannel(struct Channel * channel) {
/* close the FDs in case they haven't been done
* yet (ie they were shutdown etc */
* yet (they might have been shutdown etc) */
TRACE(("CLOSE writefd %d", channel->writefd))
close(channel->writefd);
TRACE(("CLOSE readfd %d", channel->readfd))
close(channel->readfd);
TRACE(("CLOSE errfd %d", channel->errfd))
close(channel->errfd);
channel->typedata = NULL;
deletechannel(channel);
delete_channel(channel);
TRACE(("leave removechannel"))
TRACE(("leave remove_channel"))
}
/* Remove a channel entry */
static void deletechannel(struct Channel *channel) {
static void delete_channel(struct Channel *channel) {
ses.channels[channel->index] = NULL;
m_free(channel);
@ -542,10 +558,6 @@ void recv_msg_channel_request() {
TRACE(("enter recv_msg_channel_request"))
channel = getchannel();
if (channel == NULL) {
/* disconnect ? */
dropbear_exit("Unknown channel");
}
if (channel->type->reqhandler) {
channel->type->reqhandler(channel);
@ -562,26 +574,23 @@ void recv_msg_channel_request() {
* chan is the remote channel, isextended is 0 if it is normal data, 1
* if it is extended data. if it is extended, then the type is in
* exttype */
static void send_msg_channel_data(struct Channel *channel, int isextended,
unsigned int exttype) {
static void send_msg_channel_data(struct Channel *channel, int isextended) {
buffer *buf;
int len;
unsigned int maxlen;
size_t maxlen, size_pos;
int fd;
/* TRACE(("enter send_msg_channel_data"))
TRACE(("extended = %d type = %d", isextended, exttype))*/
CHECKCLEARTOWRITE();
dropbear_assert(!channel->sentclosed);
TRACE(("enter send_msg_channel_data"))
dropbear_assert(!channel->sent_close);
if (isextended) {
fd = channel->errfd;
} else {
fd = channel->readfd;
}
TRACE(("enter send_msg_channel_data isextended %d fd %d", isextended, fd))
dropbear_assert(fd >= 0);
maxlen = MIN(channel->transwindow, channel->transmaxpacket);
@ -589,44 +598,52 @@ static void send_msg_channel_data(struct Channel *channel, int isextended,
* exttype if is extended */
maxlen = MIN(maxlen,
ses.writepayload->size - 1 - 4 - 4 - (isextended ? 4 : 0));
TRACE(("maxlen %d", maxlen))
if (maxlen == 0) {
TRACE(("leave send_msg_channel_data: no window"))
return; /* the data will get written later */
}
/* read the data */
TRACE(("maxlen %d", maxlen))
buf = buf_new(maxlen);
TRACE(("buf pos %d data %x", buf->pos, buf->data))
len = read(fd, buf_getwriteptr(buf, maxlen), maxlen);
if (len <= 0) {
/* on error/eof, send eof */
if (len == 0 || errno != EINTR) {
closereadfd(channel, fd);
}
buf_free(buf);
buf = NULL;
TRACE(("leave send_msg_channel_data: read err or EOF for fd %d",
channel->index));
return;
}
buf_incrlen(buf, len);
buf_putbyte(ses.writepayload,
isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA);
buf_putint(ses.writepayload, channel->remotechan);
if (isextended) {
buf_putint(ses.writepayload, exttype);
buf_putint(ses.writepayload, SSH_EXTENDED_DATA_STDERR);
}
/* a dummy size first ...*/
size_pos = ses.writepayload->pos;
buf_putint(ses.writepayload, 0);
buf_putstring(ses.writepayload, buf_getptr(buf, len), len);
buf_free(buf);
buf = NULL;
/* read the data */
len = read(fd, buf_getwriteptr(ses.writepayload, maxlen), maxlen);
if (len <= 0) {
if (len == 0 || errno != EINTR) {
/* This will also get hit in the case of EAGAIN. The only
time we expect to receive EAGAIN is when we're flushing a FD,
in which case it can be treated the same as EOF */
close_chan_fd(channel, fd, SHUT_RD);
}
ses.writepayload->len = ses.writepayload->pos = 0;
TRACE(("leave send_msg_channel_data: len %d read err or EOF for fd %d",
len, channel->index));
return;
}
buf_incrwritepos(ses.writepayload, len);
/* ... real size here */
buf_setpos(ses.writepayload, size_pos);
buf_putint(ses.writepayload, len);
channel->transwindow -= len;
encrypt_packet();
/* If we receive less data than we requested when flushing, we've
reached the equivalent of EOF */
if (channel->flushing && len < maxlen)
{
TRACE(("closing from channel, flushing out."))
close_chan_fd(channel, fd, SHUT_RD);
}
TRACE(("leave send_msg_channel_data"))
}
@ -636,9 +653,6 @@ void recv_msg_channel_data() {
struct Channel *channel;
channel = getchannel();
if (channel == NULL) {
dropbear_exit("Unknown channel");
}
common_recv_msg_channel_data(channel, channel->writefd, channel->writebuf);
}
@ -655,16 +669,19 @@ void common_recv_msg_channel_data(struct Channel *channel, int fd,
TRACE(("enter recv_msg_channel_data"))
if (channel->recveof) {
if (channel->recv_eof) {
dropbear_exit("received data after eof");
}
if (fd < 0) {
dropbear_exit("received data with bad writefd");
/* If we have encountered failed write, the far side might still
* be sending data without having yet received our close notification.
* We just drop the data. */
return;
}
datalen = buf_getint(ses.payload);
TRACE(("length %d", datalen))
maxdata = cbuf_getavail(cbuf);
@ -706,9 +723,6 @@ void recv_msg_channel_window_adjust() {
unsigned int incr;
channel = getchannel();
if (channel == NULL) {
dropbear_exit("Unknown channel");
}
incr = buf_getint(ses.payload);
TRACE(("received window increment %d", incr))
@ -735,7 +749,6 @@ static void send_msg_channel_window_adjust(struct Channel* channel,
}
/* Handle a new channel request, performing any channel-type-specific setup */
/* XXX server */
void recv_msg_channel_open() {
unsigned char *type;
@ -792,13 +805,13 @@ void recv_msg_channel_open() {
if (channel->type->inithandler) {
ret = channel->type->inithandler(channel);
if (ret == SSH_OPEN_IN_PROGRESS) {
/* We'll send the confirmation later */
goto cleanup;
}
if (ret > 0) {
if (ret == SSH_OPEN_IN_PROGRESS) {
/* We'll send the confirmation later */
goto cleanup;
}
errtype = ret;
deletechannel(channel);
delete_channel(channel);
TRACE(("inithandler returned failure %d", ret))
goto failure;
}
@ -882,6 +895,49 @@ static void send_msg_channel_open_confirmation(struct Channel* channel,
TRACE(("leave send_msg_channel_open_confirmation"))
}
/* close a fd, how is SHUT_RD or SHUT_WR */
static void close_chan_fd(struct Channel *channel, int fd, int how) {
int closein = 0, closeout = 0;
if (channel->type->sepfds) {
TRACE(("SHUTDOWN(%d, %d)", fd, how))
shutdown(fd, how);
if (how == 0) {
closeout = 1;
} else {
closein = 1;
}
} else {
TRACE(("CLOSE some fd %d", fd))
close(fd);
closein = closeout = 1;
}
if (closeout && (fd == channel->readfd)) {
channel->readfd = FD_CLOSED;
}
if (closeout && ERRFD_IS_READ(channel) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
if (closein && fd == channel->writefd) {
channel->writefd = FD_CLOSED;
}
if (closein && ERRFD_IS_WRITE(channel) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
/* if we called shutdown on it and all references are gone, then we
* need to close() it to stop it lingering */
if (channel->type->sepfds && channel->readfd == FD_CLOSED
&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
TRACE(("CLOSE (finally) of %d", fd))
close(fd);
}
}
#if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT)
/* Create a new channel, and start the open request. This is intended
* for X11, agent, tcp forwarding, and should be filled with channel-specific
@ -930,9 +986,6 @@ void recv_msg_channel_open_confirmation() {
TRACE(("enter recv_msg_channel_open_confirmation"))
channel = getchannel();
if (channel == NULL) {
dropbear_exit("Unknown channel");
}
if (!channel->await_open) {
dropbear_exit("unexpected channel reply");
@ -950,7 +1003,7 @@ void recv_msg_channel_open_confirmation() {
if (channel->type->inithandler) {
ret = channel->type->inithandler(channel);
if (ret > 0) {
removechannel(channel);
remove_channel(channel);
TRACE(("inithandler returned failure %d", ret))
}
}
@ -965,74 +1018,12 @@ void recv_msg_channel_open_failure() {
struct Channel * channel;
channel = getchannel();
if (channel == NULL) {
dropbear_exit("Unknown channel");
}
if (!channel->await_open) {
dropbear_exit("unexpected channel reply");
}
channel->await_open = 0;
removechannel(channel);
remove_channel(channel);
}
#endif /* USING_LISTENERS */
/* close a stdout/stderr fd */
static void closereadfd(struct Channel * channel, int fd) {
/* don't close it if it is the same as writefd,
* unless writefd is already set -1 */
TRACE(("enter closereadfd"))
closechanfd(channel, fd, 0);
TRACE(("leave closereadfd"))
}
/* close a stdin fd */
static void closewritefd(struct Channel * channel) {
TRACE(("enter closewritefd"))
closechanfd(channel, channel->writefd, 1);
TRACE(("leave closewritefd"))
}
/* close a fd, how is 0 for stdout/stderr, 1 for stdin */
static void closechanfd(struct Channel *channel, int fd, int how) {
int closein = 0, closeout = 0;
/* XXX server */
if (channel->type->sepfds) {
TRACE(("shutdown((%d), %d)", fd, how))
shutdown(fd, how);
if (how == 0) {
closeout = 1;
} else {
closein = 1;
}
} else {
close(fd);
closein = closeout = 1;
}
if (closeout && fd == channel->readfd) {
channel->readfd = FD_CLOSED;
}
if (closeout && (channel->extrabuf == NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
if (closein && fd == channel->writefd) {
channel->writefd = FD_CLOSED;
}
if (closein && (channel->extrabuf != NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
/* if we called shutdown on it and all references are gone, then we
* need to close() it to stop it lingering */
if (channel->type->sepfds && channel->readfd == FD_CLOSED
&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
close(fd);
}
}

47
common-session.c
View File

@ -61,6 +61,12 @@ void common_session_init(int sock, char* remotehost) {
ses.connecttimeout = 0;
if (pipe(ses.signal_pipe) < 0) {
dropbear_exit("signal pipe failed");
}
setnonblocking(ses.signal_pipe[0]);
setnonblocking(ses.signal_pipe[1]);
kexfirstinitialise(); /* initialise the kex state */
ses.writepayload = buf_new(MAX_TRANS_PAYLOAD_LEN);
@ -108,7 +114,6 @@ void common_session_init(int sock, char* remotehost) {
ses.allowprivport = 0;
TRACE(("leave session_init"))
}
@ -132,6 +137,10 @@ void session_loop(void(*loophandler)()) {
FD_SET(ses.sock, &writefd);
}
}
/* We get woken up when signal handlers write to this pipe.
SIGCHLD in svr-chansession is the only one currently. */
FD_SET(ses.signal_pipe[0], &readfd);
/* set up for channels which require reading/writing */
if (ses.dataallowed) {
@ -143,27 +152,29 @@ void session_loop(void(*loophandler)()) {
dropbear_exit("Terminated by signal");
}
if (val < 0) {
if (errno == EINTR) {
/* This must happen even if we've been interrupted, so that
* changed signal-handler vars can take effect etc */
if (loophandler) {
loophandler();
}
continue;
} else {
dropbear_exit("Error in select");
}
if (val < 0 && errno != EINTR) {
dropbear_exit("Error in select");
}
if (val <= 0) {
/* If we were interrupted or the select timed out, we still
* want to iterate over channels etc for reading, to handle
* server processes exiting etc.
* We don't want to read/write FDs. */
FD_ZERO(&writefd);
FD_ZERO(&readfd);
}
/* We'll just empty out the pipe if required. We don't do
any thing with the data, since the pipe's purpose is purely to
wake up the select() above. */
if (FD_ISSET(ses.signal_pipe[0], &readfd)) {
char x;
while (read(ses.signal_pipe[0], &x, 1) > 0) {}
}
/* check for auth timeout, rekeying required etc */
checktimeouts();
if (val == 0) {
/* timeout */
TRACE(("select timeout"))
continue;
}
/* process session socket's incoming/outgoing data */
if (ses.sock != -1) {

2
debug.h
View File

@ -39,7 +39,7 @@
* Caution: Don't use this in an unfriendly environment (ie unfirewalled),
* since the printing may not sanitise strings etc. This will add a reasonable
* amount to your executable size. */
/*#define DEBUG_TRACE */
#define DEBUG_TRACE
/* All functions writing to the cleartext payload buffer call
* CHECKCLEARTOWRITE() before writing. This is only really useful if you're

3
session.h
View File

@ -123,7 +123,8 @@ struct sshsession {
unsigned char lastpacket; /* What the last received packet type was */
int signal_pipe[2]; /* stores endpoints of a self-pipe used for
race-free signal handling */
/* KEX/encryption related */
struct KEXState kexstate;

24
svr-chansession.c
View File

@ -59,7 +59,6 @@ static void send_msg_chansess_exitstatus(struct Channel * channel,
struct ChanSess * chansess);
static void send_msg_chansess_exitsignal(struct Channel * channel,
struct ChanSess * chansess);
static int sesscheckclose(struct Channel *channel);
static void get_termmodes(struct ChanSess *chansess);
@ -68,7 +67,7 @@ extern char** environ;
static int sesscheckclose(struct Channel *channel) {
struct ChanSess *chansess = (struct ChanSess*)channel->typedata;
return chansess->exit.exitpid >= 0;
return chansess->exit.exitpid != -1;
}
/* Handler for childs exiting, store the state for return to the client */
@ -121,9 +120,21 @@ static void sesssigchild_handler(int UNUSED(dummy)) {
/* we use this to determine how pid exited */
exit->exitsignal = -1;
}
/* Make sure that the main select() loop wakes up */
while (1) {
/* EAGAIN means the pipe's full, so don't need to write anything */
/* isserver is just a random byte to write */
if (write(ses.signal_pipe[1], &ses.isserver, 1) == 1 || errno == EAGAIN) {
break;
}
if (errno == EINTR) {
continue;
}
dropbear_exit("error writing signal pipe");
}
}
sa_chld.sa_handler = sesssigchild_handler;
sa_chld.sa_flags = SA_NOCLDSTOP;
sigaction(SIGCHLD, &sa_chld, NULL);
@ -245,16 +256,17 @@ static void closechansess(struct Channel *channel) {
unsigned int i;
struct logininfo *li;
TRACE(("enter closechansess"))
chansess = (struct ChanSess*)channel->typedata;
send_exitsignalstatus(channel);
TRACE(("enter closechansess"))
if (chansess == NULL) {
TRACE(("leave closechansess: chansess == NULL"))
return;
}
send_exitsignalstatus(channel);
m_free(chansess->cmd);
m_free(chansess->term);