Attachment 1512 Details for Bug 1331 – Process escapes from multiplex slave sessions

[patch] Process escapes from multiplex slave sessions

ssh-mux-escapes.diff (text/plain), 15.46 KB, created by Damien Miller on 2008-06-12 11:41:23 AEST

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Creator: Damien Miller

Created: 2008-06-12 11:41:23 AEST

Size: 15.46 KB

patch

obsolete

>? r
>? sftp-server.c.xxx
>? ssh-proctitle-size.diff
>? ssh-signal-close.broken.diff
>Index: channels.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/channels.c,v
>retrieving revision 1.278
>diff -u -p -r1.278 channels.c
>--- channels.c	10 Jun 2008 04:50:25 -0000	1.278
>+++ channels.c	12 Jun 2008 01:27:00 -0000
>@@ -726,7 +726,7 @@ channel_cancel_cleanup(int id)
> 
> void
> channel_register_filter(int id, channel_infilter_fn *ifn,
>-    channel_outfilter_fn *ofn)
>+    channel_outfilter_fn *ofn, void *ctx)
> {
> 	Channel *c = channel_lookup(id);
> 
>@@ -736,6 +736,7 @@ channel_register_filter(int id, channel_
> 	}
> 	c->input_filter = ifn;
> 	c->output_filter = ofn;
>+	c->filter_ctx = ctx;
> }
> 
> void
>Index: channels.h
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/channels.h,v
>retrieving revision 1.93
>diff -u -p -r1.93 channels.h
>--- channels.h	10 Jun 2008 04:50:25 -0000	1.93
>+++ channels.h	12 Jun 2008 01:27:00 -0000
>@@ -130,6 +130,7 @@ struct Channel {
> 	/* filter */
> 	channel_infilter_fn	*input_filter;
> 	channel_outfilter_fn	*output_filter;
>+	void			*filter_ctx;
> 
> 	/* keep boundaries */
> 	int     		datagram;
>@@ -194,7 +195,7 @@ void	 channel_request_start(int, char *,
> void	 channel_register_cleanup(int, channel_callback_fn *, int);
> void	 channel_register_open_confirm(int, channel_callback_fn *, void *);
> void	 channel_register_filter(int, channel_infilter_fn *,
>-    channel_outfilter_fn *);
>+    channel_outfilter_fn *, void *);
> void	 channel_register_status_confirm(int, channel_confirm_cb *,
>     channel_confirm_abandon_cb *, void *);
> void	 channel_cancel_cleanup(int);
>Index: clientloop.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/clientloop.c,v
>retrieving revision 1.194
>diff -u -p -r1.194 clientloop.c
>--- clientloop.c	19 May 2008 20:53:52 -0000	1.194
>+++ clientloop.c	12 Jun 2008 01:27:00 -0000
>@@ -136,8 +136,8 @@ static int in_non_blocking_mode = 0;
> 
> /* Common data for the client loop code. */
> static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
>-static int escape_char;		/* Escape character. */
>-static int escape_pending;	/* Last character was the escape character */
>+static int escape_char1;	/* Escape character. (proto1 only) */
>+static int escape_pending1;	/* Last character was an escape (proto1 only) */
> static int last_was_cr;		/* Last character was a newline. */
> static int exit_status;		/* Used to store the exit status of the command. */
> static int stdin_eof;		/* EOF has been encountered on standard error. */
>@@ -154,6 +154,13 @@ static int session_closed = 0;	/* In SSH
> static void client_init_dispatch(void);
> int	session_ident = -1;
> 
>+/* Track escape per proto2 channel */
>+struct escape_filter_ctx {
>+	int escape_pending;
>+	int escape_char;
>+};
>+
>+/* Context for channel confirmation replies */
> struct channel_reply_ctx {
> 	const char *request_type;
> 	int id, do_close;
>@@ -377,8 +384,8 @@ client_check_initial_eof_on_stdin(void)
> 			 * and also process it as an escape character if
> 			 * appropriate.
> 			 */
>-			if ((u_char) buf[0] == escape_char)
>-				escape_pending = 1;
>+			if ((u_char) buf[0] == escape_char1)
>+				escape_pending1 = 1;
> 			else
> 				buffer_append(&stdin_buffer, buf, 1);
> 		}
>@@ -805,9 +812,12 @@ out:
> 		xfree(fwd.connect_host);
> }
> 
>-/* process the characters one by one */
>+/* 
>+ * Process the characters one by one, call with c==NULL for proto1 case.
>+ */
> static int
>-process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
>+process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
>+    char *buf, int len)
> {
> 	char string[1024];
> 	pid_t pid;
>@@ -815,7 +825,20 @@ process_escapes(Buffer *bin, Buffer *bou
> 	u_int i;
> 	u_char ch;
> 	char *s;
>+	int *escape_pendingp, escape_char;
>+	struct escape_filter_ctx *efc;
> 
>+	if (c == NULL) {
>+		escape_pendingp = &escape_pending1;
>+		escape_char = escape_char1;
>+	} else {
>+		if (c->filter_ctx == NULL)
>+			return 0;
>+		efc = (struct escape_filter_ctx *)c->filter_ctx;
>+		escape_pendingp = &efc->escape_pending;
>+		escape_char = efc->escape_char;
>+	}
>+	
> 	if (len <= 0)
> 		return (0);
> 
>@@ -823,25 +846,42 @@ process_escapes(Buffer *bin, Buffer *bou
> 		/* Get one character at a time. */
> 		ch = buf[i];
> 
>-		if (escape_pending) {
>+		if (*escape_pendingp) {
> 			/* We have previously seen an escape character. */
> 			/* Clear the flag now. */
>-			escape_pending = 0;
>+			*escape_pendingp = 0;
> 
> 			/* Process the escaped character. */
> 			switch (ch) {
> 			case '.':
> 				/* Terminate the connection. */
>-				snprintf(string, sizeof string, "%c.\r\n", escape_char);
>+				snprintf(string, sizeof string, "%c.\r\n",
>+				    escape_char);
> 				buffer_append(berr, string, strlen(string));
> 
>-				quit_pending = 1;
>+				if (c && c->ctl_fd != -1) {
>+					chan_read_failed(c);
>+					chan_write_failed(c);
>+				} else
>+					quit_pending = 1;
> 				return -1;
> 
> 			case 'Z' - 64:
>+				/* XXX support this for mux clients */
>+				if (c && c->ctl_fd != -1) {
>+ noescape:
>+					snprintf(string, sizeof string,
>+					    "%c%c escape not available to "
>+					    "multiplexed sessions\r\n",
>+					    escape_char, ch);
>+					buffer_append(berr, string,
>+					    strlen(string));
>+					continue;
>+				}
> 				/* Suspend the program. */
> 				/* Print a message to that effect to the user. */
>-				snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
>+				snprintf(string, sizeof string,
>+				    "%c^Z [suspend ssh]\r\n", escape_char);
> 				buffer_append(berr, string, strlen(string));
> 
> 				/* Restore terminal modes and suspend. */
>@@ -873,6 +913,8 @@ process_escapes(Buffer *bin, Buffer *bou
> 				continue;
> 
> 			case '&':
>+				if (c && c->ctl_fd != -1)
>+					goto noescape;
> 				/*
> 				 * Detach the program (continue to serve connections,
> 				 * but put in background and no more new connections).
>@@ -921,27 +963,50 @@ process_escapes(Buffer *bin, Buffer *bou
> 				continue;
> 
> 			case '?':
>-				snprintf(string, sizeof string,
>+				if (c && c->ctl_fd != -1) {
>+					snprintf(string, sizeof string,
>+"%c?\r\n\
>+Supported escape sequences:\r\n\
>+  %c.  - terminate session\r\n\
>+  %cB  - send a BREAK to the remote system\r\n\
>+  %cC  - open a command line\r\n\
>+  %cR  - Request rekey (SSH protocol 2 only)\r\n\
>+  %c#  - list forwarded connections\r\n\
>+  %c?  - this message\r\n\
>+  %c%c  - send the escape character by typing it twice\r\n\
>+(Note that escapes are only recognized immediately after newline.)\r\n",
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char);
>+				} else {
>+					snprintf(string, sizeof string,
> "%c?\r\n\
> Supported escape sequences:\r\n\
>-%c.  - terminate connection\r\n\
>-%cB  - send a BREAK to the remote system\r\n\
>-%cC  - open a command line\r\n\
>-%cR  - Request rekey (SSH protocol 2 only)\r\n\
>-%c^Z - suspend ssh\r\n\
>-%c#  - list forwarded connections\r\n\
>-%c&  - background ssh (when waiting for connections to terminate)\r\n\
>-%c?  - this message\r\n\
>-%c%c  - send the escape character by typing it twice\r\n\
>+  %c.  - terminate connection (and any multiplexed sessions)\r\n\
>+  %cB  - send a BREAK to the remote system\r\n\
>+  %cC  - open a command line\r\n\
>+  %cR  - Request rekey (SSH protocol 2 only)\r\n\
>+  %c^Z - suspend ssh\r\n\
>+  %c#  - list forwarded connections\r\n\
>+  %c&  - background ssh (when waiting for connections to terminate)\r\n\
>+  %c?  - this message\r\n\
>+  %c%c  - send the escape character by typing it twice\r\n\
> (Note that escapes are only recognized immediately after newline.)\r\n",
>-				    escape_char, escape_char, escape_char, escape_char,
>-				    escape_char, escape_char, escape_char, escape_char,
>-				    escape_char, escape_char, escape_char);
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char, escape_char,
>+					    escape_char);
>+				}
> 				buffer_append(berr, string, strlen(string));
> 				continue;
> 
> 			case '#':
>-				snprintf(string, sizeof string, "%c#\r\n", escape_char);
>+				snprintf(string, sizeof string, "%c#\r\n",
>+				    escape_char);
> 				buffer_append(berr, string, strlen(string));
> 				s = channel_open_message();
> 				buffer_append(berr, s, strlen(s));
>@@ -967,7 +1032,7 @@ Supported escape sequences:\r\n\
> 			 */
> 			if (last_was_cr && ch == escape_char) {
> 				/* It is. Set the flag and continue to next character. */
>-				escape_pending = 1;
>+				*escape_pendingp = 1;
> 				continue;
> 			}
> 		}
>@@ -1018,7 +1083,7 @@ client_process_input(fd_set *readset)
> 				packet_start(SSH_CMSG_EOF);
> 				packet_send();
> 			}
>-		} else if (escape_char == SSH_ESCAPECHAR_NONE) {
>+		} else if (escape_char1 == SSH_ESCAPECHAR_NONE) {
> 			/*
> 			 * Normal successful read, and no escape character.
> 			 * Just append the data to buffer.
>@@ -1029,8 +1094,8 @@ client_process_input(fd_set *readset)
> 			 * Normal, successful read.  But we have an escape character
> 			 * and have to process the characters one by one.
> 			 */
>-			if (process_escapes(&stdin_buffer, &stdout_buffer,
>-			    &stderr_buffer, buf, len) == -1)
>+			if (process_escapes(NULL, &stdin_buffer,
>+			    &stdout_buffer, &stderr_buffer, buf, len) == -1)
> 				return;
> 		}
> 	}
>@@ -1105,13 +1170,26 @@ client_process_buffered_input_packets(vo
> 
> /* scan buf[] for '~' before sending data to the peer */
> 
>-static int
>-simple_escape_filter(Channel *c, char *buf, int len)
>+/* Helper: allocate a new escape_filter_ctx and fill in its escape char */
>+void *
>+client_new_escape_filter_ctx(int escape_char)
>+{
>+	struct escape_filter_ctx *ret;
>+
>+	ret = xmalloc(sizeof(*ret));
>+	ret->escape_pending = 0;
>+	ret->escape_char = escape_char;
>+	return (void *)ret;
>+}
>+
>+int
>+client_simple_escape_filter(Channel *c, char *buf, int len)
> {
> 	if (c->extended_usage != CHAN_EXTENDED_WRITE)
> 		return 0;
> 
>-	return process_escapes(&c->input, &c->output, &c->extended, buf, len);
>+	return process_escapes(c, &c->input, &c->output, &c->extended,
>+	    buf, len);
> }
> 
> static void
>@@ -1143,7 +1221,7 @@ client_loop(int have_pty, int escape_cha
> 	start_time = get_current_time();
> 
> 	/* Initialize variables. */
>-	escape_pending = 0;
>+	escape_pending1 = 0;
> 	last_was_cr = 1;
> 	exit_status = -1;
> 	stdin_eof = 0;
>@@ -1170,7 +1248,7 @@ client_loop(int have_pty, int escape_cha
> 	stdout_bytes = 0;
> 	stderr_bytes = 0;
> 	quit_pending = 0;
>-	escape_char = escape_char_arg;
>+	escape_char1 = escape_char_arg;
> 
> 	/* Initialize buffers. */
> 	buffer_init(&stdin_buffer);
>@@ -1198,9 +1276,10 @@ client_loop(int have_pty, int escape_cha
> 
> 	if (compat20) {
> 		session_ident = ssh2_chan_id;
>-		if (escape_char != SSH_ESCAPECHAR_NONE)
>+		if (escape_char_arg != SSH_ESCAPECHAR_NONE)
> 			channel_register_filter(session_ident,
>-			    simple_escape_filter, NULL);
>+			    client_simple_escape_filter, NULL,
>+			    client_new_escape_filter_ctx(escape_char_arg));
> 		if (session_ident != -1)
> 			channel_register_cleanup(session_ident,
> 			    client_channel_closed, 0);
>Index: clientloop.h
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/clientloop.h,v
>retrieving revision 1.19
>diff -u -p -r1.19 clientloop.h
>--- clientloop.h	9 May 2008 14:18:44 -0000	1.19
>+++ clientloop.h	12 Jun 2008 01:27:00 -0000
>@@ -46,8 +46,12 @@ void	 client_session2_setup(int, int, in
> 	    int, Buffer *, char **);
> int	 client_request_tun_fwd(int, int, int);
> 
>+/* Escape filter for protocol 2 sessions */
>+void	*client_new_escape_filter_ctx(int);
>+int	 client_simple_escape_filter(Channel *, char *, int);
>+
> /* Multiplexing protocol version */
>-#define SSHMUX_VER			1
>+#define SSHMUX_VER			2
> 
> /* Multiplexing control protocol flags */
> #define SSHMUX_COMMAND_OPEN		1	/* Open new connection */
>@@ -59,20 +63,6 @@ int	 client_request_tun_fwd(int, int, in
> #define SSHMUX_FLAG_X11_FWD		(1<<2)	/* Request X11 forwarding */
> #define SSHMUX_FLAG_AGENT_FWD		(1<<3)	/* Request agent forwarding */
> 
>-/* Multiplexing routines */
>-
>-struct mux_session_confirm_ctx {
>-	int want_tty;
>-	int want_subsys;
>-	int want_x_fwd;
>-	int want_agent_fwd;
>-	Buffer cmd;
>-	char *term;
>-	struct termios tio;
>-	char **env;
>-};
>-
>-/* mux.c */
> void	muxserver_listen(void);
> int	muxserver_accept_control(void);
> void	muxclient(const char *);
>Index: mux.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/mux.c,v
>retrieving revision 1.1
>diff -u -p -r1.1 mux.c
>--- mux.c	9 May 2008 14:18:44 -0000	1.1
>+++ mux.c	12 Jun 2008 01:27:00 -0000
>@@ -60,6 +60,18 @@ extern char *host;
> int subsystem_flag;
> extern Buffer command;
> 
>+/* Context for session open confirmation callback */
>+struct mux_session_confirm_ctx {
>+	int want_tty;
>+	int want_subsys;
>+	int want_x_fwd;
>+	int want_agent_fwd;
>+	Buffer cmd;
>+	char *term;
>+	struct termios tio;
>+	char **env;
>+};
>+
> /* fd to control socket */
> int muxserver_sock = -1;
> 
>@@ -178,7 +190,7 @@ muxserver_accept_control(void)
> 	struct sockaddr_storage addr;
> 	struct mux_session_confirm_ctx *cctx;
> 	char *cmd;
>-	u_int i, j, len, env_len, mux_command, flags;
>+	u_int i, j, len, env_len, mux_command, flags, escape_char;
> 	uid_t euid;
> 	gid_t egid;
> 	int start_close = 0;
>@@ -305,6 +317,7 @@ muxserver_accept_control(void)
> 	cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0;
> 	cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0;
> 	cctx->term = buffer_get_string(&m, &len);
>+	escape_char = buffer_get_int(&m);
> 
> 	cmd = buffer_get_string(&m, &len);
> 	buffer_init(&cctx->cmd);
>@@ -390,8 +403,12 @@ muxserver_accept_control(void)
> 	    new_fd[0], new_fd[1], new_fd[2], window, packetmax,
> 	    CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
> 
>-	/* XXX */
> 	c->ctl_fd = client_fd;
>+	if (cctx->want_tty && escape_char != 0xffffffff) {
>+		channel_register_filter(c->self,
>+		    client_simple_escape_filter, NULL,
>+		    client_new_escape_filter_ctx((int)escape_char));
>+	}
> 
> 	debug3("%s: channel_new: %d", __func__, c->self);
> 
>@@ -549,33 +566,34 @@ muxclient(const char *path)
> 		fprintf(stderr, "Exit request sent.\r\n");
> 		exit(0);
> 	case SSHMUX_COMMAND_OPEN:
>-		/* continue below */
>+		buffer_put_cstring(&m, term ? term : "");
>+		if (options.escape_char == SSH_ESCAPECHAR_NONE)
>+			buffer_put_int(&m, 0xffffffff);
>+		else
>+			buffer_put_int(&m, options.escape_char);
>+		buffer_append(&command, "\0", 1);
>+		buffer_put_cstring(&m, buffer_ptr(&command));
>+
>+		if (options.num_send_env == 0 || environ == NULL) {
>+			buffer_put_int(&m, 0);
>+		} else {
>+			/* Pass environment */
>+			num_env = 0;
>+			for (i = 0; environ[i] != NULL; i++) {
>+				if (env_permitted(environ[i]))
>+					num_env++; /* Count */
>+			}
>+			buffer_put_int(&m, num_env);
>+		for (i = 0; environ[i] != NULL && num_env >= 0; i++) {
>+				if (env_permitted(environ[i])) {
>+					num_env--;
>+					buffer_put_cstring(&m, environ[i]);
>+				}
>+			}
>+		}
> 		break;
> 	default:
>-		fatal("silly muxclient_command %d", muxclient_command);
>-	}
>-
>-	/* SSHMUX_COMMAND_OPEN */
>-	buffer_put_cstring(&m, term ? term : "");
>-	buffer_append(&command, "\0", 1);
>-	buffer_put_cstring(&m, buffer_ptr(&command));
>-
>-	if (options.num_send_env == 0 || environ == NULL) {
>-		buffer_put_int(&m, 0);
>-	} else {
>-		/* Pass environment */
>-		num_env = 0;
>-		for (i = 0; environ[i] != NULL; i++)
>-			if (env_permitted(environ[i]))
>-				num_env++; /* Count */
>-
>-		buffer_put_int(&m, num_env);
>-
>-		for (i = 0; environ[i] != NULL && num_env >= 0; i++)
>-			if (env_permitted(environ[i])) {
>-				num_env--;
>-				buffer_put_cstring(&m, environ[i]);
>-			}
>+		fatal("unrecognised muxclient_command %d", muxclient_command);
> 	}
> 
> 	if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)

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Attachments on bug 1331: 1512 | 1854