upstream commit

refactor channels.c

Move static state to a "struct ssh_channels" that is allocated at
runtime and tracked as a member of struct ssh.

Explicitly pass "struct ssh" to all channels functions.

Replace use of the legacy packet APIs in channels.c.

Rework sshd_config PermitOpen handling: previously the configuration
parser would call directly into the channels layer. After the refactor
this is not possible, as the channels structures are allocated at
connection time and aren't available when the configuration is parsed.
The server config parser now tracks PermitOpen itself and explicitly
configures the channels code later.

ok markus@

Upstream-ID: 11828f161656b965cc306576422613614bea2d8f

1 files changed, 101 insertions, 79 deletions

diff --git a/channels.h b/channels.h
index 5ecb4d7c..f04c43af 100644
--- a/channels.h
+++ b/channels.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.127 2017/08/30 03:59:08 djm Exp $ */
+/* $OpenBSD: channels.h,v 1.128 2017/09/12 06:32:07 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -64,16 +64,18 @@
 struct ssh;
 struct Channel;
 typedef struct Channel Channel;
+struct fwd_perm_list;
 
-typedef void channel_open_fn(int, int, void *);
-typedef void channel_callback_fn(int, void *);
-typedef int channel_infilter_fn(struct Channel *, char *, int);
-typedef void channel_filter_cleanup_fn(int, void *);
-typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
+typedef void channel_open_fn(struct ssh *, int, int, void *);
+typedef void channel_callback_fn(struct ssh *, int, void *);
+typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
+typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
+typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
+    u_char **, size_t *);
 
 /* Channel success/failure callbacks */
-typedef void channel_confirm_cb(int, struct Channel *, void *);
-typedef void channel_confirm_abandon_cb(struct Channel *, void *);
+typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
+typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
 struct channel_confirm {
 	TAILQ_ENTRY(channel_confirm) entry;
 	channel_confirm_cb *cb;
@@ -90,12 +92,13 @@ struct channel_connect {
 };
 
 /* Callbacks for mux channels back into client-specific code */
-typedef int mux_callback_fn(struct Channel *);
+typedef int mux_callback_fn(struct ssh *, struct Channel *);
 
 struct Channel {
 	int     type;		/* channel type/state */
 	int     self;		/* my own channel identifier */
 	int     remote_id;	/* channel identifier for remote peer */
+				/* XXX should be uint32_t */
 	u_int   istate;		/* input from channel (state of receive half) */
 	u_int   ostate;		/* output to channel  (state of transmit half) */
 	int     flags;		/* close sent/rcvd */
@@ -116,11 +119,12 @@ struct Channel {
 				 * to a matching pre-select handler.
 				 * this way post-select handlers are not
 				 * accidentally called if a FD gets reused */
-	Buffer  input;		/* data read from socket, to be sent over
+	struct sshbuf *input;	/* data read from socket, to be sent over
 				 * encrypted connection */
-	Buffer  output;		/* data received over encrypted connection for
+	struct sshbuf *output;	/* data received over encrypted connection for
 				 * send on socket */
-	Buffer  extended;
+	struct sshbuf *extended;
+
 	char    *path;
 		/* path for unix domain sockets, or host name for forwards */
 	int     listening_port;	/* port being listened for forwards */
@@ -156,6 +160,7 @@ struct Channel {
 	int     		datagram;
 
 	/* non-blocking connect */
+	/* XXX make this a pointer so the structure can be opaque */
 	struct channel_connect	connect_ctx;
 
 	/* multiplexing protocol hook, called for each packet received */
@@ -195,44 +200,55 @@ struct Channel {
 #define CHAN_EOF_RCVD			0x08
 #define CHAN_LOCAL			0x10
 
-#define CHAN_RBUF	16*1024
+/* Read buffer size */
+#define CHAN_RBUF	(16*1024)
+
+/* Hard limit on number of channels */
+#define CHANNELS_MAX_CHANNELS	(16*1024)
 
 /* check whether 'efd' is still in use */
 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 	(c->extended_usage == CHAN_EXTENDED_READ && \
 	(c->efd != -1 || \
-	buffer_len(&c->extended) > 0))
+	sshbuf_len(c->extended) > 0))
 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 	(c->extended_usage == CHAN_EXTENDED_WRITE && \
 	c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
-	buffer_len(&c->extended) > 0))
+	sshbuf_len(c->extended) > 0))
+
+/* Add channel management structures to SSH transport instance */
+void channel_init_channels(struct ssh *ssh);
 
 /* channel management */
 
-Channel	*channel_by_id(int);
-Channel	*channel_by_remote_id(int);
-Channel	*channel_lookup(int);
-Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
-void	 channel_set_fds(int, int, int, int, int, int, int, u_int);
-void	 channel_free(Channel *);
-void	 channel_free_all(void);
-void	 channel_stop_listening(void);
-
-void	 channel_send_open(int);
-void	 channel_request_start(int, char *, int);
-void	 channel_register_cleanup(int, channel_callback_fn *, int);
-void	 channel_register_open_confirm(int, channel_open_fn *, void *);
-void	 channel_register_filter(int, channel_infilter_fn *,
-    channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
-void	 channel_register_status_confirm(int, channel_confirm_cb *,
-    channel_confirm_abandon_cb *, void *);
-void	 channel_cancel_cleanup(int);
-int	 channel_close_fd(int *);
-void	 channel_send_window_changes(void);
+Channel	*channel_by_id(struct ssh *, int);
+Channel	*channel_by_remote_id(struct ssh *, int);
+Channel	*channel_lookup(struct ssh *, int);
+Channel *channel_new(struct ssh *, char *, int, int, int, int,
+	    u_int, u_int, int, char *, int);
+void	 channel_set_fds(struct ssh *, int, int, int, int, int,
+	    int, int, u_int);
+void	 channel_free(struct ssh *, Channel *);
+void	 channel_free_all(struct ssh *);
+void	 channel_stop_listening(struct ssh *);
+
+void	 channel_send_open(struct ssh *, int);
+void	 channel_request_start(struct ssh *, int, char *, int);
+void	 channel_register_cleanup(struct ssh *, int,
+	    channel_callback_fn *, int);
+void	 channel_register_open_confirm(struct ssh *, int,
+	    channel_open_fn *, void *);
+void	 channel_register_filter(struct ssh *, int, channel_infilter_fn *,
+	    channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
+void	 channel_register_status_confirm(struct ssh *, int,
+	    channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
+void	 channel_cancel_cleanup(struct ssh *, int);
+int	 channel_close_fd(struct ssh *, int *);
+void	 channel_send_window_changes(struct ssh *);
 
 /* mux proxy support */
 
-int	 channel_proxy_downstream(Channel *mc);
+int	 channel_proxy_downstream(struct ssh *, Channel *mc);
 int	 channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
 
 /* protocol handler */
@@ -252,63 +268,69 @@ int	 channel_input_status_confirm(int, u_int32_t, struct ssh *);
 void	 channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *,
 	     u_int*, time_t*);
 void     channel_after_select(struct ssh *, fd_set *, fd_set *);
-void     channel_output_poll(void);
+void     channel_output_poll(struct ssh *);
 
-int      channel_not_very_much_buffered_data(void);
-void     channel_close_all(void);
-int      channel_still_open(void);
-char	*channel_open_message(void);
-int	 channel_find_open(void);
+int      channel_not_very_much_buffered_data(struct ssh *);
+void     channel_close_all(struct ssh *);
+int      channel_still_open(struct ssh *);
+char	*channel_open_message(struct ssh *);
+int	 channel_find_open(struct ssh *);
 
 /* tcp forwarding */
 struct Forward;
 struct ForwardOptions;
-void	 channel_set_af(int af);
-void     channel_permit_all_opens(void);
-void	 channel_add_permitted_opens(char *, int);
-int	 channel_add_adm_permitted_opens(char *, int);
-void	 channel_disable_adm_local_opens(void);
-void	 channel_update_permitted_opens(int, int);
-void	 channel_clear_permitted_opens(void);
-void	 channel_clear_adm_permitted_opens(void);
-void 	 channel_print_adm_permitted_opens(void);
-Channel	*channel_connect_to_port(const char *, u_short, char *, char *, int *,
-	     const char **);
-Channel *channel_connect_to_path(const char *, char *, char *);
-Channel	*channel_connect_stdio_fwd(const char*, u_short, int, int);
-Channel	*channel_connect_by_listen_address(const char *, u_short,
-	     char *, char *);
-Channel	*channel_connect_by_listen_path(const char *, char *, char *);
-int	 channel_request_remote_forwarding(struct Forward *);
-int	 channel_setup_local_fwd_listener(struct Forward *, struct ForwardOptions *);
-int	 channel_request_rforward_cancel(struct Forward *);
-int	 channel_setup_remote_fwd_listener(struct Forward *, int *, struct ForwardOptions *);
-int	 channel_cancel_rport_listener(struct Forward *);
-int	 channel_cancel_lport_listener(struct Forward *, int, struct ForwardOptions *);
+void	 channel_set_af(struct ssh *, int af);
+void     channel_permit_all_opens(struct ssh *);
+void	 channel_add_permitted_opens(struct ssh *, char *, int);
+int	 channel_add_adm_permitted_opens(struct ssh *, char *, int);
+void	 channel_copy_adm_permitted_opens(struct ssh *,
+	    const struct fwd_perm_list *);
+void	 channel_disable_adm_local_opens(struct ssh *);
+void	 channel_update_permitted_opens(struct ssh *, int, int);
+void	 channel_clear_permitted_opens(struct ssh *);
+void	 channel_clear_adm_permitted_opens(struct ssh *);
+void 	 channel_print_adm_permitted_opens(struct ssh *);
+Channel	*channel_connect_to_port(struct ssh *, const char *, u_short,
+	    char *, char *, int *, const char **);
+Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
+Channel	*channel_connect_stdio_fwd(struct ssh *, const char*,
+	    u_short, int, int);
+Channel	*channel_connect_by_listen_address(struct ssh *, const char *,
+	    u_short, char *, char *);
+Channel	*channel_connect_by_listen_path(struct ssh *, const char *,
+	    char *, char *);
+int	 channel_request_remote_forwarding(struct ssh *, struct Forward *);
+int	 channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
+	    struct ForwardOptions *);
+int	 channel_request_rforward_cancel(struct ssh *, struct Forward *);
+int	 channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
+	    int *, struct ForwardOptions *);
+int	 channel_cancel_rport_listener(struct ssh *, struct Forward *);
+int	 channel_cancel_lport_listener(struct ssh *, struct Forward *,
+	    int, struct ForwardOptions *);
 int	 permitopen_port(const char *);
 
 /* x11 forwarding */
 
-void	 channel_set_x11_refuse_time(u_int);
-int	 x11_connect_display(void);
-int	 x11_create_display_inet(int, int, int, u_int *, int **);
-void	 x11_request_forwarding_with_spoofing(int, const char *, const char *,
-	     const char *, int);
+void	 channel_set_x11_refuse_time(struct ssh *, u_int);
+int	 x11_connect_display(struct ssh *);
+int	 x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
+void	 x11_request_forwarding_with_spoofing(struct ssh *, int,
+	    const char *, const char *, const char *, int);
 
 /* channel close */
 
-int	 chan_is_dead(Channel *, int);
-void	 chan_mark_dead(Channel *);
+int	 chan_is_dead(struct ssh *, Channel *, int);
+void	 chan_mark_dead(struct ssh *, Channel *);
 
 /* channel events */
 
-void	 chan_rcvd_oclose(Channel *);
-void	 chan_rcvd_eow(Channel *);	/* SSH2-only */
-void	 chan_read_failed(Channel *);
-void	 chan_ibuf_empty(Channel *);
-
-void	 chan_rcvd_ieof(Channel *);
-void	 chan_write_failed(Channel *);
-void	 chan_obuf_empty(Channel *);
+void	 chan_rcvd_oclose(struct ssh *, Channel *);
+void	 chan_rcvd_eow(struct ssh *, Channel *);
+void	 chan_read_failed(struct ssh *, Channel *);
+void	 chan_ibuf_empty(struct ssh *, Channel *);
+void	 chan_rcvd_ieof(struct ssh *, Channel *);
+void	 chan_write_failed(struct ssh *, Channel *);
+void	 chan_obuf_empty(struct ssh *, Channel *);
 
 #endif