1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include "audit-type.h"
24 #include "string-util.h"
25 #include "journald-audit.h"
27 typedef struct MapField
{
28 const char *audit_field
;
29 const char *journal_field
;
30 int (*map
)(const char *field
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
);
33 static int map_simple_field(const char *field
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
) {
34 _cleanup_free_
char *c
= NULL
;
35 size_t l
= 0, allocated
= 0;
45 c
= malloc(allocated
);
50 for (e
= *p
; *e
!= ' ' && *e
!= 0; e
++) {
51 if (!GREEDY_REALLOC(c
, allocated
, l
+2))
59 if (!GREEDY_REALLOC(*iov
, *n_iov_allocated
, *n_iov
+ 1))
62 (*iov
)[*n_iov
].iov_base
= c
;
63 (*iov
)[*n_iov
].iov_len
= l
;
72 static int map_string_field_internal(const char *field
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
, bool filter_printable
) {
73 _cleanup_free_
char *c
= NULL
;
82 /* The kernel formats string fields in one of two formats. */
85 /* Normal quoted syntax */
91 l
= strlen(field
) + (e
- s
);
96 *((char*) mempcpy(stpcpy(c
, field
), s
, e
- s
)) = 0;
100 } else if (unhexchar(**p
) >= 0) {
101 /* Hexadecimal escaping */
102 size_t allocated
= 0;
106 c
= malloc(allocated
);
111 for (e
= *p
; *e
!= ' ' && *e
!= 0; e
+= 2) {
123 x
= ((uint8_t) a
<< 4 | (uint8_t) b
);
125 if (filter_printable
&& x
< (uint8_t) ' ')
128 if (!GREEDY_REALLOC(c
, allocated
, l
+2))
138 if (!GREEDY_REALLOC(*iov
, *n_iov_allocated
, *n_iov
+ 1))
141 (*iov
)[*n_iov
].iov_base
= c
;
142 (*iov
)[*n_iov
].iov_len
= l
;
151 static int map_string_field(const char *field
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
) {
152 return map_string_field_internal(field
, p
, iov
, n_iov_allocated
, n_iov
, false);
155 static int map_string_field_printable(const char *field
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
) {
156 return map_string_field_internal(field
, p
, iov
, n_iov_allocated
, n_iov
, true);
159 static int map_generic_field(const char *prefix
, const char **p
, struct iovec
**iov
, size_t *n_iov_allocated
, unsigned *n_iov
) {
164 /* Implements fallback mappings for all fields we don't know */
166 for (e
= *p
; e
< *p
+ 16; e
++) {
168 if (*e
== 0 || *e
== ' ')
174 if (!((*e
>= 'a' && *e
<= 'z') ||
175 (*e
>= 'A' && *e
<= 'Z') ||
176 (*e
>= '0' && *e
<= '9') ||
177 *e
== '_' || *e
== '-'))
181 if (e
<= *p
|| e
>= *p
+ 16)
184 c
= alloca(strlen(prefix
) + (e
- *p
) + 2);
186 t
= stpcpy(c
, prefix
);
187 for (f
= *p
; f
< e
; f
++) {
190 if (*f
>= 'a' && *f
<= 'z')
191 x
= (*f
- 'a') + 'A'; /* uppercase */
193 x
= '_'; /* dashes → underscores */
203 r
= map_simple_field(c
, &e
, iov
, n_iov_allocated
, n_iov
);
211 /* Kernel fields are those occurring in the audit string before
212 * msg='. All of these fields are trusted, hence carry the "_" prefix.
213 * We try to translate the fields we know into our native names. The
214 * other's are generically mapped to _AUDIT_FIELD_XYZ= */
215 static const MapField map_fields_kernel
[] = {
217 /* First, we map certain well-known audit fields into native
218 * well-known fields */
219 { "pid=", "_PID=", map_simple_field
},
220 { "ppid=", "_PPID=", map_simple_field
},
221 { "uid=", "_UID=", map_simple_field
},
222 { "euid=", "_EUID=", map_simple_field
},
223 { "fsuid=", "_FSUID=", map_simple_field
},
224 { "gid=", "_GID=", map_simple_field
},
225 { "egid=", "_EGID=", map_simple_field
},
226 { "fsgid=", "_FSGID=", map_simple_field
},
227 { "tty=", "_TTY=", map_simple_field
},
228 { "ses=", "_AUDIT_SESSION=", map_simple_field
},
229 { "auid=", "_AUDIT_LOGINUID=", map_simple_field
},
230 { "subj=", "_SELINUX_CONTEXT=", map_simple_field
},
231 { "comm=", "_COMM=", map_string_field
},
232 { "exe=", "_EXE=", map_string_field
},
233 { "proctitle=", "_CMDLINE=", map_string_field_printable
},
235 /* Some fields don't map to native well-known fields. However,
236 * we know that they are string fields, hence let's undo
237 * string field escaping for them, though we stick to the
238 * generic field names. */
239 { "path=", "_AUDIT_FIELD_PATH=", map_string_field
},
240 { "dev=", "_AUDIT_FIELD_DEV=", map_string_field
},
241 { "name=", "_AUDIT_FIELD_NAME=", map_string_field
},
245 /* Userspace fields are those occurring in the audit string after
246 * msg='. All of these fields are untrusted, hence carry no "_"
247 * prefix. We map the fields we don't know to AUDIT_FIELD_XYZ= */
248 static const MapField map_fields_userspace
[] = {
249 { "cwd=", "AUDIT_FIELD_CWD=", map_string_field
},
250 { "cmd=", "AUDIT_FIELD_CMD=", map_string_field
},
251 { "acct=", "AUDIT_FIELD_ACCT=", map_string_field
},
252 { "exe=", "AUDIT_FIELD_EXE=", map_string_field
},
253 { "comm=", "AUDIT_FIELD_COMM=", map_string_field
},
257 static int map_all_fields(
259 const MapField map_fields
[],
263 size_t *n_iov_allocated
,
270 assert(n_iov_allocated
);
278 p
+= strspn(p
, WHITESPACE
);
284 v
= startswith(p
, "msg='");
289 /* Userspace message. It's enclosed in
290 simple quotation marks, is not
291 escaped, but the last field in the
292 line, hence let's remove the
293 quotation mark, and apply the
294 userspace mapping instead of the
297 e
= endswith(v
, "'");
299 return 0; /* don't continue splitting up if the final quotation mark is missing */
301 c
= strndupa(v
, e
- v
);
302 return map_all_fields(c
, map_fields_userspace
, "AUDIT_FIELD_", false, iov
, n_iov_allocated
, n_iov
);
306 /* Try to map the kernel fields to our own names */
307 for (m
= map_fields
; m
->audit_field
; m
++) {
308 v
= startswith(p
, m
->audit_field
);
312 r
= m
->map(m
->journal_field
, &v
, iov
, n_iov_allocated
, n_iov
);
314 return log_debug_errno(r
, "Failed to parse audit array: %m");
324 r
= map_generic_field(prefix
, &p
, iov
, n_iov_allocated
, n_iov
);
326 return log_debug_errno(r
, "Failed to parse audit array: %m");
329 /* Couldn't process as generic field, let's just skip over it */
330 p
+= strcspn(p
, WHITESPACE
);
335 static void process_audit_string(Server
*s
, int type
, const char *data
, size_t size
) {
336 _cleanup_free_
struct iovec
*iov
= NULL
;
337 size_t n_iov_allocated
= 0;
338 unsigned n_iov
= 0, k
;
339 uint64_t seconds
, msec
, id
;
340 const char *p
, *type_name
;
342 char id_field
[sizeof("_AUDIT_ID=") + DECIMAL_STR_MAX(uint64_t)],
343 type_field
[sizeof("_AUDIT_TYPE=") + DECIMAL_STR_MAX(int)],
344 source_time_field
[sizeof("_SOURCE_REALTIME_TIMESTAMP=") + DECIMAL_STR_MAX(usec_t
)];
355 /* Note that the input buffer is NUL terminated, but let's
356 * check whether there is a spurious NUL byte */
357 if (memchr(data
, 0, size
))
360 p
= startswith(data
, "audit");
364 if (sscanf(p
, "(%" PRIu64
".%" PRIu64
":%" PRIu64
"):%n",
372 p
+= strspn(p
, WHITESPACE
);
377 n_iov_allocated
= N_IOVEC_META_FIELDS
+ 7;
378 iov
= new(struct iovec
, n_iov_allocated
);
384 IOVEC_SET_STRING(iov
[n_iov
++], "_TRANSPORT=audit");
386 sprintf(source_time_field
, "_SOURCE_REALTIME_TIMESTAMP=%" PRIu64
,
387 (usec_t
) seconds
* USEC_PER_SEC
+ (usec_t
) msec
* USEC_PER_MSEC
);
388 IOVEC_SET_STRING(iov
[n_iov
++], source_time_field
);
390 sprintf(type_field
, "_AUDIT_TYPE=%i", type
);
391 IOVEC_SET_STRING(iov
[n_iov
++], type_field
);
393 sprintf(id_field
, "_AUDIT_ID=%" PRIu64
, id
);
394 IOVEC_SET_STRING(iov
[n_iov
++], id_field
);
396 assert_cc(32 == LOG_AUTH
);
397 IOVEC_SET_STRING(iov
[n_iov
++], "SYSLOG_FACILITY=32");
398 IOVEC_SET_STRING(iov
[n_iov
++], "SYSLOG_IDENTIFIER=audit");
400 type_name
= audit_type_name_alloca(type
);
402 m
= strjoina("MESSAGE=", type_name
, " ", p
);
403 IOVEC_SET_STRING(iov
[n_iov
++], m
);
407 map_all_fields(p
, map_fields_kernel
, "_AUDIT_FIELD_", true, &iov
, &n_iov_allocated
, &n_iov
);
409 if (!GREEDY_REALLOC(iov
, n_iov_allocated
, n_iov
+ N_IOVEC_META_FIELDS
)) {
414 server_dispatch_message(s
, iov
, n_iov
, n_iov_allocated
, NULL
, NULL
, NULL
, 0, NULL
, LOG_NOTICE
, 0);
417 /* free() all entries that map_all_fields() added. All others
418 * are allocated on the stack or are constant. */
420 for (; z
< n_iov
; z
++)
421 free(iov
[z
].iov_base
);
424 void server_process_audit_message(
428 const struct ucred
*ucred
,
429 const union sockaddr_union
*sa
,
432 const struct nlmsghdr
*nl
= buffer
;
436 if (buffer_size
< ALIGN(sizeof(struct nlmsghdr
)))
441 /* Filter out fake data */
443 salen
!= sizeof(struct sockaddr_nl
) ||
444 sa
->nl
.nl_family
!= AF_NETLINK
||
445 sa
->nl
.nl_pid
!= 0) {
446 log_debug("Audit netlink message from invalid sender.");
450 if (!ucred
|| ucred
->pid
!= 0) {
451 log_debug("Audit netlink message with invalid credentials.");
455 if (!NLMSG_OK(nl
, buffer_size
)) {
456 log_error("Audit netlink message truncated.");
460 /* Ignore special Netlink messages */
461 if (IN_SET(nl
->nlmsg_type
, NLMSG_NOOP
, NLMSG_ERROR
))
464 /* Below AUDIT_FIRST_USER_MSG theer are only control messages, let's ignore those */
465 if (nl
->nlmsg_type
< AUDIT_FIRST_USER_MSG
)
468 process_audit_string(s
, nl
->nlmsg_type
, NLMSG_DATA(nl
), nl
->nlmsg_len
- ALIGN(sizeof(struct nlmsghdr
)));
471 static int enable_audit(int fd
, bool b
) {
474 struct nlmsghdr header
;
475 uint8_t header_space
[NLMSG_HDRLEN
];
477 struct audit_status body
;
478 } _packed_ request
= {
479 .header
.nlmsg_len
= NLMSG_LENGTH(sizeof(struct audit_status
)),
480 .header
.nlmsg_type
= AUDIT_SET
,
481 .header
.nlmsg_flags
= NLM_F_REQUEST
,
482 .header
.nlmsg_seq
= 1,
483 .header
.nlmsg_pid
= 0,
484 .body
.mask
= AUDIT_STATUS_ENABLED
,
487 union sockaddr_union sa
= {
488 .nl
.nl_family
= AF_NETLINK
,
491 struct iovec iovec
= {
492 .iov_base
= &request
,
493 .iov_len
= NLMSG_LENGTH(sizeof(struct audit_status
)),
499 .msg_namelen
= sizeof(sa
.nl
),
504 n
= sendmsg(fd
, &mh
, MSG_NOSIGNAL
);
507 if (n
!= NLMSG_LENGTH(sizeof(struct audit_status
)))
510 /* We don't wait for the result here, we can't do anything
516 int server_open_audit(Server
*s
) {
517 static const int one
= 1;
520 if (s
->audit_fd
< 0) {
521 static const union sockaddr_union sa
= {
522 .nl
.nl_family
= AF_NETLINK
,
524 .nl
.nl_groups
= AUDIT_NLGRP_READLOG
,
527 s
->audit_fd
= socket(AF_NETLINK
, SOCK_RAW
|SOCK_CLOEXEC
|SOCK_NONBLOCK
, NETLINK_AUDIT
);
528 if (s
->audit_fd
< 0) {
529 if (errno
== EAFNOSUPPORT
|| errno
== EPROTONOSUPPORT
)
530 log_debug("Audit not supported in the kernel.");
532 log_warning_errno(errno
, "Failed to create audit socket, ignoring: %m");
537 if (bind(s
->audit_fd
, &sa
.sa
, sizeof(sa
.nl
)) < 0) {
538 log_warning_errno(errno
,
539 "Failed to join audit multicast group. "
540 "The kernel is probably too old or multicast reading is not supported. "
542 s
->audit_fd
= safe_close(s
->audit_fd
);
546 fd_nonblock(s
->audit_fd
, 1);
548 r
= setsockopt(s
->audit_fd
, SOL_SOCKET
, SO_PASSCRED
, &one
, sizeof(one
));
550 return log_error_errno(errno
, "Failed to set SO_PASSCRED on audit socket: %m");
552 r
= sd_event_add_io(s
->event
, &s
->audit_event_source
, s
->audit_fd
, EPOLLIN
, server_process_datagram
, s
);
554 return log_error_errno(r
, "Failed to add audit fd to event loop: %m");
556 /* We are listening now, try to enable audit */
557 r
= enable_audit(s
->audit_fd
, true);
559 log_warning_errno(r
, "Failed to issue audit enable call: %m");