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putty-source/unix/uxpeer.c

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Log identifying information for the other end of connections. When anyone connects to a PuTTY tool's listening socket - whether it's a user of a local->remote port forwarding, a connection-sharing downstream or a client of Pageant - we'd like to log as much information as we can find out about where the connection came from. To that end, I've implemented a function sk_peer_info() in the socket abstraction, which returns a freeform text string as best it can (or NULL, if it can't get anything at all) describing the thing at the other end of the connection. For TCP connections, this is done using getpeername() to get an IP address and port in the obvious way; for Unix-domain sockets, we attempt SO_PEERCRED (conditionalised on some moderately hairy autoconfery) to get the pid and owner of the peer. I haven't implemented anything for Windows named pipes, but I will if I hear of anything useful.
2015-05-18 13:57:45 +01:00
/*
* Unix: wrapper for getsockopt(SO_PEERCRED), conditionalised on
* appropriate autoconfery.
*/
#ifdef HAVE_CONFIG_H
# include "uxconfig.h" /* leading space prevents mkfiles.pl trying to follow */
#endif
#ifdef HAVE_SO_PEERCRED
#define _GNU_SOURCE
#include <features.h>
#endif
#include <sys/socket.h>
#include "putty.h"
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 19:23:19 +00:00
bool so_peercred(int fd, int *pid, int *uid, int *gid)
Log identifying information for the other end of connections. When anyone connects to a PuTTY tool's listening socket - whether it's a user of a local->remote port forwarding, a connection-sharing downstream or a client of Pageant - we'd like to log as much information as we can find out about where the connection came from. To that end, I've implemented a function sk_peer_info() in the socket abstraction, which returns a freeform text string as best it can (or NULL, if it can't get anything at all) describing the thing at the other end of the connection. For TCP connections, this is done using getpeername() to get an IP address and port in the obvious way; for Unix-domain sockets, we attempt SO_PEERCRED (conditionalised on some moderately hairy autoconfery) to get the pid and owner of the peer. I haven't implemented anything for Windows named pipes, but I will if I hear of anything useful.
2015-05-18 13:57:45 +01:00
{
#ifdef HAVE_SO_PEERCRED
struct ucred cr;
socklen_t crlen = sizeof(cr);
if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &crlen) == 0) {
*pid = cr.pid;
*uid = cr.uid;
*gid = cr.gid;
Adopt C99 <stdbool.h>'s true/false. This commit includes <stdbool.h> from defs.h and deletes my traditional definitions of TRUE and FALSE, but other than that, it's a 100% mechanical search-and-replace transforming all uses of TRUE and FALSE into the C99-standardised lowercase spellings. No actual types are changed in this commit; that will come next. This is just getting the noise out of the way, so that subsequent commits can have a higher proportion of signal.
2018-10-29 19:50:29 +00:00
return true;
Log identifying information for the other end of connections. When anyone connects to a PuTTY tool's listening socket - whether it's a user of a local->remote port forwarding, a connection-sharing downstream or a client of Pageant - we'd like to log as much information as we can find out about where the connection came from. To that end, I've implemented a function sk_peer_info() in the socket abstraction, which returns a freeform text string as best it can (or NULL, if it can't get anything at all) describing the thing at the other end of the connection. For TCP connections, this is done using getpeername() to get an IP address and port in the obvious way; for Unix-domain sockets, we attempt SO_PEERCRED (conditionalised on some moderately hairy autoconfery) to get the pid and owner of the peer. I haven't implemented anything for Windows named pipes, but I will if I hear of anything useful.
2015-05-18 13:57:45 +01:00
}
#endif
Adopt C99 <stdbool.h>'s true/false. This commit includes <stdbool.h> from defs.h and deletes my traditional definitions of TRUE and FALSE, but other than that, it's a 100% mechanical search-and-replace transforming all uses of TRUE and FALSE into the C99-standardised lowercase spellings. No actual types are changed in this commit; that will come next. This is just getting the noise out of the way, so that subsequent commits can have a higher proportion of signal.
2018-10-29 19:50:29 +00:00
return false;
Log identifying information for the other end of connections. When anyone connects to a PuTTY tool's listening socket - whether it's a user of a local->remote port forwarding, a connection-sharing downstream or a client of Pageant - we'd like to log as much information as we can find out about where the connection came from. To that end, I've implemented a function sk_peer_info() in the socket abstraction, which returns a freeform text string as best it can (or NULL, if it can't get anything at all) describing the thing at the other end of the connection. For TCP connections, this is done using getpeername() to get an IP address and port in the obvious way; for Unix-domain sockets, we attempt SO_PEERCRED (conditionalised on some moderately hairy autoconfery) to get the pid and owner of the peer. I haven't implemented anything for Windows named pipes, but I will if I hear of anything useful.
2015-05-18 13:57:45 +01:00
}
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