1/* $OpenBSD: log.c,v 1.61 2023/12/06 21:06:48 djm Exp $ */
2/*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 *                    All rights reserved
6 *
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose.  Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
12 */
13/*
14 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include "includes.h"
38
39#include <sys/types.h>
40
41#include <fcntl.h>
42#include <stdarg.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <syslog.h>
47#include <unistd.h>
48#include <errno.h>
49#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
50# include <vis.h>
51#endif
52
53#include "log.h"
54#include "match.h"
55
56static LogLevel log_level = SYSLOG_LEVEL_INFO;
57static int log_on_stderr = 1;
58static int log_stderr_fd = STDERR_FILENO;
59static int log_facility = LOG_AUTH;
60static const char *argv0;
61static log_handler_fn *log_handler;
62static void *log_handler_ctx;
63static char **log_verbose;
64static size_t nlog_verbose;
65
66extern char *__progname;
67
68#define LOG_SYSLOG_VIS	(VIS_CSTYLE|VIS_NL|VIS_TAB|VIS_OCTAL)
69#define LOG_STDERR_VIS	(VIS_SAFE|VIS_OCTAL)
70
71/* textual representation of log-facilities/levels */
72
73static struct {
74	const char *name;
75	SyslogFacility val;
76} log_facilities[] = {
77	{ "DAEMON",	SYSLOG_FACILITY_DAEMON },
78	{ "USER",	SYSLOG_FACILITY_USER },
79	{ "AUTH",	SYSLOG_FACILITY_AUTH },
80#ifdef LOG_AUTHPRIV
81	{ "AUTHPRIV",	SYSLOG_FACILITY_AUTHPRIV },
82#endif
83	{ "LOCAL0",	SYSLOG_FACILITY_LOCAL0 },
84	{ "LOCAL1",	SYSLOG_FACILITY_LOCAL1 },
85	{ "LOCAL2",	SYSLOG_FACILITY_LOCAL2 },
86	{ "LOCAL3",	SYSLOG_FACILITY_LOCAL3 },
87	{ "LOCAL4",	SYSLOG_FACILITY_LOCAL4 },
88	{ "LOCAL5",	SYSLOG_FACILITY_LOCAL5 },
89	{ "LOCAL6",	SYSLOG_FACILITY_LOCAL6 },
90	{ "LOCAL7",	SYSLOG_FACILITY_LOCAL7 },
91	{ NULL,		SYSLOG_FACILITY_NOT_SET }
92};
93
94static struct {
95	const char *name;
96	LogLevel val;
97} log_levels[] =
98{
99	{ "QUIET",	SYSLOG_LEVEL_QUIET },
100	{ "FATAL",	SYSLOG_LEVEL_FATAL },
101	{ "ERROR",	SYSLOG_LEVEL_ERROR },
102	{ "INFO",	SYSLOG_LEVEL_INFO },
103	{ "VERBOSE",	SYSLOG_LEVEL_VERBOSE },
104	{ "DEBUG",	SYSLOG_LEVEL_DEBUG1 },
105	{ "DEBUG1",	SYSLOG_LEVEL_DEBUG1 },
106	{ "DEBUG2",	SYSLOG_LEVEL_DEBUG2 },
107	{ "DEBUG3",	SYSLOG_LEVEL_DEBUG3 },
108	{ NULL,		SYSLOG_LEVEL_NOT_SET }
109};
110
111LogLevel
112log_level_get(void)
113{
114	return log_level;
115}
116
117SyslogFacility
118log_facility_number(char *name)
119{
120	int i;
121
122	if (name != NULL)
123		for (i = 0; log_facilities[i].name; i++)
124			if (strcasecmp(log_facilities[i].name, name) == 0)
125				return log_facilities[i].val;
126	return SYSLOG_FACILITY_NOT_SET;
127}
128
129const char *
130log_facility_name(SyslogFacility facility)
131{
132	u_int i;
133
134	for (i = 0;  log_facilities[i].name; i++)
135		if (log_facilities[i].val == facility)
136			return log_facilities[i].name;
137	return NULL;
138}
139
140LogLevel
141log_level_number(char *name)
142{
143	int i;
144
145	if (name != NULL)
146		for (i = 0; log_levels[i].name; i++)
147			if (strcasecmp(log_levels[i].name, name) == 0)
148				return log_levels[i].val;
149	return SYSLOG_LEVEL_NOT_SET;
150}
151
152const char *
153log_level_name(LogLevel level)
154{
155	u_int i;
156
157	for (i = 0; log_levels[i].name != NULL; i++)
158		if (log_levels[i].val == level)
159			return log_levels[i].name;
160	return NULL;
161}
162
163void
164log_verbose_add(const char *s)
165{
166	char **tmp;
167
168	/* Ignore failures here */
169	if ((tmp = recallocarray(log_verbose, nlog_verbose, nlog_verbose + 1,
170	    sizeof(*log_verbose))) != NULL) {
171		log_verbose = tmp;
172		if ((log_verbose[nlog_verbose] = strdup(s)) != NULL)
173			nlog_verbose++;
174	}
175}
176
177void
178log_verbose_reset(void)
179{
180	size_t i;
181
182	for (i = 0; i < nlog_verbose; i++)
183		free(log_verbose[i]);
184	free(log_verbose);
185	log_verbose = NULL;
186	nlog_verbose = 0;
187}
188
189/*
190 * Initialize the log.
191 */
192
193void
194log_init(const char *av0, LogLevel level, SyslogFacility facility,
195    int on_stderr)
196{
197#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
198	struct syslog_data sdata = SYSLOG_DATA_INIT;
199#endif
200
201	argv0 = av0;
202
203	if (log_change_level(level) != 0) {
204		fprintf(stderr, "Unrecognized internal syslog level code %d\n",
205		    (int) level);
206		exit(1);
207	}
208
209	log_handler = NULL;
210	log_handler_ctx = NULL;
211
212	log_on_stderr = on_stderr;
213	if (on_stderr)
214		return;
215
216	switch (facility) {
217	case SYSLOG_FACILITY_DAEMON:
218		log_facility = LOG_DAEMON;
219		break;
220	case SYSLOG_FACILITY_USER:
221		log_facility = LOG_USER;
222		break;
223	case SYSLOG_FACILITY_AUTH:
224		log_facility = LOG_AUTH;
225		break;
226#ifdef LOG_AUTHPRIV
227	case SYSLOG_FACILITY_AUTHPRIV:
228		log_facility = LOG_AUTHPRIV;
229		break;
230#endif
231	case SYSLOG_FACILITY_LOCAL0:
232		log_facility = LOG_LOCAL0;
233		break;
234	case SYSLOG_FACILITY_LOCAL1:
235		log_facility = LOG_LOCAL1;
236		break;
237	case SYSLOG_FACILITY_LOCAL2:
238		log_facility = LOG_LOCAL2;
239		break;
240	case SYSLOG_FACILITY_LOCAL3:
241		log_facility = LOG_LOCAL3;
242		break;
243	case SYSLOG_FACILITY_LOCAL4:
244		log_facility = LOG_LOCAL4;
245		break;
246	case SYSLOG_FACILITY_LOCAL5:
247		log_facility = LOG_LOCAL5;
248		break;
249	case SYSLOG_FACILITY_LOCAL6:
250		log_facility = LOG_LOCAL6;
251		break;
252	case SYSLOG_FACILITY_LOCAL7:
253		log_facility = LOG_LOCAL7;
254		break;
255	default:
256		fprintf(stderr,
257		    "Unrecognized internal syslog facility code %d\n",
258		    (int) facility);
259		exit(1);
260	}
261
262	/*
263	 * If an external library (eg libwrap) attempts to use syslog
264	 * immediately after reexec, syslog may be pointing to the wrong
265	 * facility, so we force an open/close of syslog here.
266	 */
267#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
268	openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
269	closelog_r(&sdata);
270#else
271	openlog(argv0 ? argv0 : __progname, LOG_PID, log_facility);
272	closelog();
273#endif
274}
275
276int
277log_change_level(LogLevel new_log_level)
278{
279	/* no-op if log_init has not been called */
280	if (argv0 == NULL)
281		return 0;
282
283	switch (new_log_level) {
284	case SYSLOG_LEVEL_QUIET:
285	case SYSLOG_LEVEL_FATAL:
286	case SYSLOG_LEVEL_ERROR:
287	case SYSLOG_LEVEL_INFO:
288	case SYSLOG_LEVEL_VERBOSE:
289	case SYSLOG_LEVEL_DEBUG1:
290	case SYSLOG_LEVEL_DEBUG2:
291	case SYSLOG_LEVEL_DEBUG3:
292		log_level = new_log_level;
293		return 0;
294	default:
295		return -1;
296	}
297}
298
299int
300log_is_on_stderr(void)
301{
302	return log_on_stderr && log_stderr_fd == STDERR_FILENO;
303}
304
305/* redirect what would usually get written to stderr to specified file */
306void
307log_redirect_stderr_to(const char *logfile)
308{
309	int fd;
310
311	if (logfile == NULL) {
312		if (log_stderr_fd != STDERR_FILENO) {
313			close(log_stderr_fd);
314			log_stderr_fd = STDERR_FILENO;
315		}
316		return;
317	}
318
319	if ((fd = open(logfile, O_WRONLY|O_CREAT|O_APPEND, 0600)) == -1) {
320		fprintf(stderr, "Couldn't open logfile %s: %s\n", logfile,
321		    strerror(errno));
322		exit(1);
323	}
324	log_stderr_fd = fd;
325}
326
327#define MSGBUFSIZ 1024
328
329void
330set_log_handler(log_handler_fn *handler, void *ctx)
331{
332	log_handler = handler;
333	log_handler_ctx = ctx;
334}
335
336static void
337do_log(LogLevel level, int force, const char *suffix, const char *fmt,
338    va_list args)
339{
340#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
341	struct syslog_data sdata = SYSLOG_DATA_INIT;
342#endif
343	char msgbuf[MSGBUFSIZ];
344	char fmtbuf[MSGBUFSIZ];
345	char *txt = NULL;
346	int pri = LOG_INFO;
347	int saved_errno = errno;
348	log_handler_fn *tmp_handler;
349	const char *progname = argv0 != NULL ? argv0 : __progname;
350
351	if (!force && level > log_level)
352		return;
353
354	switch (level) {
355	case SYSLOG_LEVEL_FATAL:
356		if (!log_on_stderr)
357			txt = "fatal";
358		pri = LOG_CRIT;
359		break;
360	case SYSLOG_LEVEL_ERROR:
361		if (!log_on_stderr)
362			txt = "error";
363		pri = LOG_ERR;
364		break;
365	case SYSLOG_LEVEL_INFO:
366		pri = LOG_INFO;
367		break;
368	case SYSLOG_LEVEL_VERBOSE:
369		pri = LOG_INFO;
370		break;
371	case SYSLOG_LEVEL_DEBUG1:
372		txt = "debug1";
373		pri = LOG_DEBUG;
374		break;
375	case SYSLOG_LEVEL_DEBUG2:
376		txt = "debug2";
377		pri = LOG_DEBUG;
378		break;
379	case SYSLOG_LEVEL_DEBUG3:
380		txt = "debug3";
381		pri = LOG_DEBUG;
382		break;
383	default:
384		txt = "internal error";
385		pri = LOG_ERR;
386		break;
387	}
388	if (txt != NULL && log_handler == NULL) {
389		snprintf(fmtbuf, sizeof(fmtbuf), "%s: %s", txt, fmt);
390		vsnprintf(msgbuf, sizeof(msgbuf), fmtbuf, args);
391	} else {
392		vsnprintf(msgbuf, sizeof(msgbuf), fmt, args);
393	}
394	if (suffix != NULL) {
395		snprintf(fmtbuf, sizeof(fmtbuf), "%s: %s", msgbuf, suffix);
396		strlcpy(msgbuf, fmtbuf, sizeof(msgbuf));
397	}
398	strnvis(fmtbuf, msgbuf, sizeof(fmtbuf),
399	    log_on_stderr ? LOG_STDERR_VIS : LOG_SYSLOG_VIS);
400	if (log_handler != NULL) {
401		/* Avoid recursion */
402		tmp_handler = log_handler;
403		log_handler = NULL;
404		tmp_handler(level, force, fmtbuf, log_handler_ctx);
405		log_handler = tmp_handler;
406	} else if (log_on_stderr) {
407		snprintf(msgbuf, sizeof msgbuf, "%s%s%.*s\r\n",
408		    (log_on_stderr > 1) ? progname : "",
409		    (log_on_stderr > 1) ? ": " : "",
410		    (int)sizeof msgbuf - 3, fmtbuf);
411		(void)write(log_stderr_fd, msgbuf, strlen(msgbuf));
412	} else {
413#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
414		openlog_r(progname, LOG_PID, log_facility, &sdata);
415		syslog_r(pri, &sdata, "%.500s", fmtbuf);
416		closelog_r(&sdata);
417#else
418		openlog(progname, LOG_PID, log_facility);
419		syslog(pri, "%.500s", fmtbuf);
420		closelog();
421#endif
422	}
423	errno = saved_errno;
424}
425
426void
427sshlog(const char *file, const char *func, int line, int showfunc,
428    LogLevel level, const char *suffix, const char *fmt, ...)
429{
430	va_list args;
431
432	va_start(args, fmt);
433	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
434	va_end(args);
435}
436
437void
438sshlogdie(const char *file, const char *func, int line, int showfunc,
439    LogLevel level, const char *suffix, const char *fmt, ...)
440{
441	va_list args;
442
443	va_start(args, fmt);
444	sshlogv(file, func, line, showfunc, SYSLOG_LEVEL_INFO,
445	    suffix, fmt, args);
446	va_end(args);
447	cleanup_exit(255);
448}
449
450void
451sshsigdie(const char *file, const char *func, int line, int showfunc,
452    LogLevel level, const char *suffix, const char *fmt, ...)
453{
454	va_list args;
455
456	va_start(args, fmt);
457	sshlogv(file, func, line, showfunc, SYSLOG_LEVEL_FATAL,
458	    suffix, fmt, args);
459	va_end(args);
460	_exit(1);
461}
462
463void
464sshlogv(const char *file, const char *func, int line, int showfunc,
465    LogLevel level, const char *suffix, const char *fmt, va_list args)
466{
467	char tag[128], fmt2[MSGBUFSIZ + 128];
468	int forced = 0;
469	const char *cp;
470	size_t i;
471
472	/* short circuit processing early if we're not going to log anything */
473	if (nlog_verbose == 0 && level > log_level)
474		return;
475
476	snprintf(tag, sizeof(tag), "%.48s:%.48s():%d (pid=%ld)",
477	    (cp = strrchr(file, '/')) == NULL ? file : cp + 1, func, line,
478	    (long)getpid());
479	for (i = 0; i < nlog_verbose; i++) {
480		if (match_pattern_list(tag, log_verbose[i], 0) == 1) {
481			forced = 1;
482			break;
483		}
484	}
485
486	if (forced)
487		snprintf(fmt2, sizeof(fmt2), "%s: %s", tag, fmt);
488	else if (showfunc)
489		snprintf(fmt2, sizeof(fmt2), "%s: %s", func, fmt);
490	else
491		strlcpy(fmt2, fmt, sizeof(fmt2));
492
493	do_log(level, forced, suffix, fmt2, args);
494}
495
496void
497sshlogdirect(LogLevel level, int forced, const char *fmt, ...)
498{
499	va_list args;
500
501	va_start(args, fmt);
502	do_log(level, forced, NULL, fmt, args);
503	va_end(args);
504}
505