nhyatt/putty-source
1
0
Fork 0
mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
Code Issues Projects Releases Wiki Activity
a48e897f26
putty-source/sshppl.h

150 lines
6.2 KiB
C
Raw Normal View History

Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
/*
* Abstraction of the various layers of SSH packet-level protocol,
* general enough to take in all three of the main SSH-2 layers and
* both of the SSH-1 phases.
*/
#ifndef PUTTY_SSHPPL_H
#define PUTTY_SSHPPL_H
typedef void (*packet_handler_fn_t)(PacketProtocolLayer *ppl, PktIn *pktin);
struct PacketProtocolLayerVtable {
void (*free)(PacketProtocolLayer *);
void (*process_queue)(PacketProtocolLayer *ppl);
int (*get_specials)(
PacketProtocolLayer *ppl, add_special_fn_t add_special, void *ctx);
void (*special_cmd)(
PacketProtocolLayer *ppl, SessionSpecialCode code, int arg);
int (*want_user_input)(PacketProtocolLayer *ppl);
void (*got_user_input)(PacketProtocolLayer *ppl);
void (*reconfigure)(PacketProtocolLayer *ppl, Conf *conf);
/* Protocol-level name of this layer. */
const char *name;
};
struct PacketProtocolLayer {
const struct PacketProtocolLayerVtable *vt;
/* Link to the underlying SSH BPP. */
BinaryPacketProtocol *bpp;
/* Queue from which the layer receives its input packets, and one
* to put its output packets on. */
PktInQueue *in_pq;
PktOutQueue *out_pq;
/* Idempotent callback that in_pq will be linked to, causing a
* call to the process_queue method. in_pq points to this, so it
* will be automatically triggered by pushing things on the
* layer's input queue, but it can also be triggered on purpose. */
IdempotentCallback ic_process_queue;
/* Owner's pointer to this layer. Permits a layer to unilaterally
* abdicate in favour of a replacement, by overwriting this
* pointer and then freeing itself. */
PacketProtocolLayer **selfptr;
/* Bufchain of keyboard input from the user, for login prompts and
* similar. */
bufchain *user_input;
/* Logging and error-reporting facilities. */
Refactor the LogContext type. LogContext is now the owner of the logevent() function that back ends and so forth are constantly calling. Previously, logevent was owned by the Frontend, which would store the message into its list for the GUI Event Log dialog (or print it to standard error, or whatever) and then pass it _back_ to LogContext to write to the currently open log file. Now it's the other way round: LogContext gets the message from the back end first, writes it to its log file if it feels so inclined, and communicates it back to the front end. This means that lots of parts of the back end system no longer need to have a pointer to a full-on Frontend; the only thing they needed it for was logging, so now they just have a LogContext (which many of them had to have anyway, e.g. for logging SSH packets or session traffic). LogContext itself also doesn't get a full Frontend pointer any more: it now talks back to the front end via a little vtable of its own called LogPolicy, which contains the method that passes Event Log entries through, the old askappend() function that decides whether to truncate a pre-existing log file, and an emergency function for printing an especially prominent message if the log file can't be created. One minor nice effect of this is that console and GUI apps can implement that last function subtly differently, so that Unix console apps can write it with a plain \n instead of the \r\n (harmless but inelegant) that the old centralised implementation generated. One other consequence of this is that the LogContext has to be provided to backend_init() so that it's available to backends from the instant of creation, rather than being provided via a separate API call a couple of function calls later, because backends have typically started doing things that need logging (like making network connections) before the call to backend_provide_logctx. Fortunately, there's no case in the whole code base where we don't already have logctx by the time we make a backend (so I don't actually remember why I ever delayed providing one). So that shortens the backend API by one function, which is always nice. While I'm tidying up, I've also moved the printf-style logeventf() and the handy logevent_and_free() into logging.c, instead of having copies of them scattered around other places. This has also let me remove some stub functions from a couple of outlying applications like Pageant. Finally, I've removed the pointless "_tag" at the end of LogContext's official struct name.
2018-10-10 18:26:18 +00:00
LogContext *logctx;
New abstraction 'Seat', to pass to backends. This is a new vtable-based abstraction which is passed to a backend in place of Frontend, and it implements only the subset of the Frontend functions needed by a backend. (Many other Frontend functions still exist, notably the wide range of things called by terminal.c providing platform-independent operations on the GUI terminal window.) The purpose of making it a vtable is that this opens up the possibility of creating a backend as an internal implementation detail of some other activity, by providing just that one backend with a custom Seat that implements the methods differently. For example, this refactoring should make it feasible to directly implement an SSH proxy type, aka the 'jump host' feature supported by OpenSSH, aka 'open a secondary SSH session in MAINCHAN_DIRECT_TCP mode, and then expose the main channel of that as the Socket for the primary connection'. (Which of course you can already do by spawning 'plink -nc' as a separate proxy process, but this would permit it in the _same_ process without anything getting confused.) I've centralised a full set of stub methods in misc.c for the new abstraction, which allows me to get rid of several annoying stubs in the previous code. Also, while I'm here, I've moved a lot of duplicated modalfatalbox() type functions from application main program files into wincons.c / uxcons.c, which I think saves duplication overall. (A minor visible effect is that the prefixes on those console-based fatal error messages will now be more consistent between applications.)
2018-10-11 18:58:42 +00:00
Seat *seat; /* for dialog boxes, session output etc */
Get rid of lots of implicit pointer types. All the main backend structures - Ssh, Telnet, Pty, Serial etc - now describe structure types themselves rather than pointers to them. The same goes for the codebase-wide trait types Socket and Plug, and the supporting types SockAddr and Pinger. All those things that were typedefed as pointers are older types; the newer ones have the explicit * at the point of use, because that's what I now seem to be preferring. But whichever one of those is better, inconsistently using a mixture of the two styles is worse, so let's make everything consistent. A few types are still implicitly pointers, such as Bignum and some of the GSSAPI types; generally this is either because they have to be void *, or because they're typedefed differently on different platforms and aren't always pointers at all. Can't be helped. But I've got rid of the main ones, at least.
2018-10-04 18:10:23 +00:00
Ssh *ssh; /* for session termination + assorted connection-layer ops */
Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
/* Known bugs in the remote implementation. */
unsigned remote_bugs;
};
#define ssh_ppl_process_queue(ppl) ((ppl)->vt->process_queue(ppl))
#define ssh_ppl_get_specials(ppl, add, ctx) \
((ppl)->vt->get_specials(ppl, add, ctx))
#define ssh_ppl_special_cmd(ppl, code, arg) \
((ppl)->vt->special_cmd(ppl, code, arg))
#define ssh_ppl_want_user_input(ppl) ((ppl)->vt->want_user_input(ppl))
#define ssh_ppl_got_user_input(ppl) ((ppl)->vt->got_user_input(ppl))
#define ssh_ppl_reconfigure(ppl, conf) ((ppl)->vt->reconfigure(ppl, conf))
/* ssh_ppl_free is more than just a macro wrapper on the vtable; it
* does centralised parts of the freeing too. */
void ssh_ppl_free(PacketProtocolLayer *ppl);
/* Helper routine to point a PPL at its input and output queues. Also
* sets up the IdempotentCallback on the input queue to trigger a call
* to process_queue whenever packets are added to it. */
void ssh_ppl_setup_queues(PacketProtocolLayer *ppl,
PktInQueue *inq, PktOutQueue *outq);
/* Routine a PPL can call to abdicate in favour of a replacement, by
* overwriting ppl->selfptr. Has the side effect of freeing 'old', so
* if 'old' actually called this (which is likely) then it should
* avoid dereferencing itself on return from this function! */
void ssh_ppl_replace(PacketProtocolLayer *old, PacketProtocolLayer *new);
PacketProtocolLayer *ssh1_login_new(
Conf *conf, const char *host, int port,
PacketProtocolLayer *successor_layer);
PacketProtocolLayer *ssh1_connection_new(
Get rid of lots of implicit pointer types. All the main backend structures - Ssh, Telnet, Pty, Serial etc - now describe structure types themselves rather than pointers to them. The same goes for the codebase-wide trait types Socket and Plug, and the supporting types SockAddr and Pinger. All those things that were typedefed as pointers are older types; the newer ones have the explicit * at the point of use, because that's what I now seem to be preferring. But whichever one of those is better, inconsistently using a mixture of the two styles is worse, so let's make everything consistent. A few types are still implicitly pointers, such as Bignum and some of the GSSAPI types; generally this is either because they have to be void *, or because they're typedefed differently on different platforms and aren't always pointers at all. Can't be helped. But I've got rid of the main ones, at least.
2018-10-04 18:10:23 +00:00
Ssh *ssh, Conf *conf, ConnectionLayer **cl_out);
Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
struct DataTransferStats;
struct ssh_connection_shared_gss_state;
PacketProtocolLayer *ssh2_transport_new(
Conf *conf, const char *host, int port, const char *fullhostname,
const char *client_greeting, const char *server_greeting,
struct ssh_connection_shared_gss_state *shgss,
struct DataTransferStats *stats,
PacketProtocolLayer *higher_layer);
PacketProtocolLayer *ssh2_userauth_new(
PacketProtocolLayer *successor_layer,
const char *hostname, const char *fullhostname,
Filename *keyfile, int tryagent,
const char *default_username, int change_username,
int try_ki_auth,
int try_gssapi_auth, int try_gssapi_kex_auth,
int gssapi_fwd, struct ssh_connection_shared_gss_state *shgss);
PacketProtocolLayer *ssh2_connection_new(
Get rid of lots of implicit pointer types. All the main backend structures - Ssh, Telnet, Pty, Serial etc - now describe structure types themselves rather than pointers to them. The same goes for the codebase-wide trait types Socket and Plug, and the supporting types SockAddr and Pinger. All those things that were typedefed as pointers are older types; the newer ones have the explicit * at the point of use, because that's what I now seem to be preferring. But whichever one of those is better, inconsistently using a mixture of the two styles is worse, so let's make everything consistent. A few types are still implicitly pointers, such as Bignum and some of the GSSAPI types; generally this is either because they have to be void *, or because they're typedefed differently on different platforms and aren't always pointers at all. Can't be helped. But I've got rid of the main ones, at least.
2018-10-04 18:10:23 +00:00
Ssh *ssh, ssh_sharing_state *connshare, int is_simple,
Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
Conf *conf, const char *peer_verstring, ConnectionLayer **cl_out);
/* Can't put this in the userauth constructor without having a
* dependency loop at setup time (transport and userauth can't _both_
* be constructed second and given a pointer to the other). */
void ssh2_userauth_set_transport_layer(PacketProtocolLayer *userauth,
PacketProtocolLayer *transport);
/* Convenience macro for protocol layers to send formatted strings to
* the Event Log. Assumes a function parameter called 'ppl' is in
* scope, and takes a double pair of parens because it passes a whole
* argument list to dupprintf. */
#define ppl_logevent(params) ( \
Refactor the LogContext type. LogContext is now the owner of the logevent() function that back ends and so forth are constantly calling. Previously, logevent was owned by the Frontend, which would store the message into its list for the GUI Event Log dialog (or print it to standard error, or whatever) and then pass it _back_ to LogContext to write to the currently open log file. Now it's the other way round: LogContext gets the message from the back end first, writes it to its log file if it feels so inclined, and communicates it back to the front end. This means that lots of parts of the back end system no longer need to have a pointer to a full-on Frontend; the only thing they needed it for was logging, so now they just have a LogContext (which many of them had to have anyway, e.g. for logging SSH packets or session traffic). LogContext itself also doesn't get a full Frontend pointer any more: it now talks back to the front end via a little vtable of its own called LogPolicy, which contains the method that passes Event Log entries through, the old askappend() function that decides whether to truncate a pre-existing log file, and an emergency function for printing an especially prominent message if the log file can't be created. One minor nice effect of this is that console and GUI apps can implement that last function subtly differently, so that Unix console apps can write it with a plain \n instead of the \r\n (harmless but inelegant) that the old centralised implementation generated. One other consequence of this is that the LogContext has to be provided to backend_init() so that it's available to backends from the instant of creation, rather than being provided via a separate API call a couple of function calls later, because backends have typically started doing things that need logging (like making network connections) before the call to backend_provide_logctx. Fortunately, there's no case in the whole code base where we don't already have logctx by the time we make a backend (so I don't actually remember why I ever delayed providing one). So that shortens the backend API by one function, which is always nice. While I'm tidying up, I've also moved the printf-style logeventf() and the handy logevent_and_free() into logging.c, instead of having copies of them scattered around other places. This has also let me remove some stub functions from a couple of outlying applications like Pageant. Finally, I've removed the pointless "_tag" at the end of LogContext's official struct name.
2018-10-10 18:26:18 +00:00
logevent_and_free((ppl)->logctx, dupprintf params))
Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
/* Convenience macro for protocol layers to send formatted strings to
* the terminal. Also expects 'ppl' to be in scope and takes double
* parens. */
#define ppl_printf(params) \
ssh_ppl_user_output_string_and_free(ppl, dupprintf params)
void ssh_ppl_user_output_string_and_free(PacketProtocolLayer *ppl, char *text);
/* Methods for userauth to communicate back to the transport layer */
ptrlen ssh2_transport_get_session_id(PacketProtocolLayer *ssh2_transport_ptr);
void ssh2_transport_notify_auth_done(PacketProtocolLayer *ssh2_transport_ptr);
/* Methods for ssh1login to pass protocol flags to ssh1connection */
void ssh1_connection_set_local_protoflags(PacketProtocolLayer *ppl, int flags);
/* Shared get_specials method between the two ssh1 layers */
int ssh1_common_get_specials(PacketProtocolLayer *, add_special_fn_t, void *);
Move client-specific SSH code into new files. This is a major code reorganisation in preparation for making this code base into one that can build an SSH server as well as a client. (Mostly for purposes of using the server as a regression test suite for the client, though I have some other possible uses in mind too. However, it's currently no part of my plan to harden the server to the point where it can sensibly be deployed in a hostile environment.) In this preparatory commit, I've broken up the SSH-2 transport and connection layers, and the SSH-1 connection layer, into multiple source files, with each layer having its own header file containing the shared type definitions. In each case, the new source file contains code that's specific to the client side of the protocol, so that a new file can be swapped in in its place when building the server. Mostly this is just a straightforward moving of code without changing it very much, but there are a couple of actual changes in the process: The parsing of SSH-2 global-request and channel open-messages is now done by a new pair of functions in the client module. For channel opens, I've invented a new union data type to be the return value from that function, representing either failure (plus error message), success (plus Channel instance to manage the new channel), or an instruction to hand the channel over to a sharing downstream (plus a pointer to the downstream in question). Also, the tree234 of remote port forwardings in ssh2connection is now initialised on first use by the client-specific code, so that's where its compare function lives. The shared ssh2connection_free() still takes responsibility for freeing it, but now has to check if it's non-null first. The outer shell of the ssh2_lportfwd_open method, for making a local-to-remote port forwarding, is still centralised in ssh2connection.c, but the part of it that actually constructs the outgoing channel-open message has moved into the client code, because that will have to change depending on whether the channel-open has to have type direct-tcpip or forwarded-tcpip. In the SSH-1 connection layer, half the filter_queue method has moved out into the new client-specific code, but not all of it - bidirectional channel maintenance messages are still handled centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in both directions, but with subtly different semantics - from server to client, it's referring to a previously established remote forwarding (and must be rejected if there isn't one that matches it), but from client to server it's just a "direct-tcpip" request with no prior context. So that one is in the client-specific module, and when I add the server code it will have its own different handler.
2018-10-20 16:57:37 +00:00
/* Other shared functions between ssh1 layers */
int ssh1_common_filter_queue(PacketProtocolLayer *ppl);
void ssh1_compute_session_id(
unsigned char *session_id, const unsigned char *cookie,
struct RSAKey *hostkey, struct RSAKey *servkey);
Move most of ssh.c out into separate source files. I've tried to separate out as many individually coherent changes from this work as I could into their own commits, but here's where I run out and have to commit the rest of this major refactoring as a big-bang change. Most of ssh.c is now no longer in ssh.c: all five of the main coroutines that handle layers of the SSH-1 and SSH-2 protocols now each have their own source file to live in, and a lot of the supporting functions have moved into the appropriate one of those too. The new abstraction is a vtable called 'PacketProtocolLayer', which has an input and output packet queue. Each layer's main coroutine is invoked from the method ssh_ppl_process_queue(), which is usually (though not exclusively) triggered automatically when things are pushed on the input queue. In SSH-2, the base layer is the transport protocol, and it contains a pair of subsidiary queues by which it passes some of its packets to the higher SSH-2 layers - first userauth and then connection, which are peers at the same level, with the former abdicating in favour of the latter at the appropriate moment. SSH-1 is simpler: the whole login phase of the protocol (crypto setup and authentication) is all in one module, and since SSH-1 has no repeat key exchange, that setup layer abdicates in favour of the connection phase when it's done. ssh.c itself is now about a tenth of its old size (which all by itself is cause for celebration!). Its main job is to set up all the layers, hook them up to each other and to the BPP, and to funnel data back and forth between that collection of modules and external things such as the network and the terminal. Once it's set up a collection of packet protocol layers, it communicates with them partly by calling methods of the base layer (and if that's ssh2transport then it will delegate some functionality to the corresponding methods of its higher layer), and partly by talking directly to the connection layer no matter where it is in the stack by means of the separate ConnectionLayer vtable which I introduced in commit 8001dd4cb, and to which I've now added quite a few extra methods replacing services that used to be internal function calls within ssh.c. (One effect of this is that the SSH-1 and SSH-2 channel storage is now no longer shared - there are distinct struct types ssh1_channel and ssh2_channel. That means a bit more code duplication, but on the plus side, a lot fewer confusing conditionals in the middle of half-shared functions, and less risk of a piece of SSH-1 escaping into SSH-2 or vice versa, which I remember has happened at least once in the past.) The bulk of this commit introduces the five new source files, their common header sshppl.h and some shared supporting routines in sshcommon.c, and rewrites nearly all of ssh.c itself. But it also includes a couple of other changes that I couldn't separate easily enough: Firstly, there's a new handling for socket EOF, in which ssh.c sets an 'input_eof' flag in the BPP, and that responds by checking a flag that tells it whether to report the EOF as an error or not. (This is the main reason for those new BPP_READ / BPP_WAITFOR macros - they can check the EOF flag every time the coroutine is resumed.) Secondly, the error reporting itself is changed around again. I'd expected to put some data fields in the public PacketProtocolLayer structure that it could set to report errors in the same way as the BPPs have been doing, but in the end, I decided propagating all those data fields around was a pain and that even the BPPs shouldn't have been doing it that way. So I've reverted to a system where everything calls back to functions in ssh.c itself to report any connection- ending condition. But there's a new family of those functions, categorising the possible such conditions by semantics, and each one has a different set of detailed effects (e.g. how rudely to close the network connection, what exit status should be passed back to the whole application, whether to send a disconnect message and/or display a GUI error box). I don't expect this to be immediately perfect: of course, the code has been through a big upheaval, new bugs are expected, and I haven't been able to do a full job of testing (e.g. I haven't tested every auth or kex method). But I've checked that it _basically_ works - both SSH protocols, all the different kinds of forwarding channel, more than one auth method, Windows and Linux, connection sharing - and I think it's now at the point where the easiest way to find further bugs is to let it out into the wild and see what users can spot.
2018-09-24 17:28:16 +00:00
#endif /* PUTTY_SSHPPL_H */
Reference in New Issue Copy Permalink