1/*
2 * Copyright (c) 2006-2017 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29#include <sys/errno.h>
30#include <sys/types.h>
31#include <sys/malloc.h>
32#include <sys/buf.h>
33#include <sys/time.h>
34#include <sys/kauth.h>
35#include <sys/mount.h>
36#include <sys/vnode.h>
37#include <sys/syslog.h>
38#include <sys/vnode_internal.h>
39#include <sys/fslog.h>
40#include <sys/mount_internal.h>
41#include <sys/kasl.h>
42
43#include <sys/queue.h>
44#include <kern/kalloc.h>
45
46#include <uuid/uuid.h>
47
48#include <stdarg.h>
49
50/* Log information about external modification of a process,
51 * using MessageTracer formatting. Assumes that both the caller
52 * and target are appropriately locked.
53 * Currently prints following information -
54 * 1. Caller process name (truncated to 16 characters)
55 * 2. Caller process Mach-O UUID
56 * 3. Target process name (truncated to 16 characters)
57 * 4. Target process Mach-O UUID
58 */
59void
60fslog_extmod_msgtracer(proc_t caller, proc_t target)
61{
62 if ((caller != PROC_NULL) && (target != PROC_NULL)) {
63
64 /*
65 * Print into buffer large enough for "ThisIsAnApplicat(BC223DD7-B314-42E0-B6B0-C5D2E6638337)",
66 * including space for escaping, and NUL byte included in sizeof(uuid_string_t).
67 */
68
69 uuid_string_t uuidstr;
70 char c_name[2*MAXCOMLEN + 2 /* () */ + sizeof(uuid_string_t)];
71 char t_name[2*MAXCOMLEN + 2 /* () */ + sizeof(uuid_string_t)];
72
73 strlcpy(c_name, caller->p_comm, sizeof(c_name));
74 uuid_unparse_upper(caller->p_uuid, uuidstr);
75 strlcat(c_name, "(", sizeof(c_name));
76 strlcat(c_name, uuidstr, sizeof(c_name));
77 strlcat(c_name, ")", sizeof(c_name));
78 if (0 != escape_str(c_name, strlen(c_name) + 1, sizeof(c_name))) {
79 return;
80 }
81
82 strlcpy(t_name, target->p_comm, sizeof(t_name));
83 uuid_unparse_upper(target->p_uuid, uuidstr);
84 strlcat(t_name, "(", sizeof(t_name));
85 strlcat(t_name, uuidstr, sizeof(t_name));
86 strlcat(t_name, ")", sizeof(t_name));
87 if (0 != escape_str(t_name, strlen(t_name) + 1, sizeof(t_name))) {
88 return;
89 }
90#if DEBUG
91 printf("EXTMOD: %s(%d) -> %s(%d)\n",
92 c_name,
93 proc_pid(caller),
94 t_name,
95 proc_pid(target));
96#endif
97
98 kern_asl_msg(LOG_DEBUG, "messagetracer",
99 5,
100 "com.apple.message.domain", "com.apple.kernel.external_modification", /* 0 */
101 "com.apple.message.signature", c_name, /* 1 */
102 "com.apple.message.signature2", t_name, /* 2 */
103 "com.apple.message.result", "noop", /* 3 */
104 "com.apple.message.summarize", "YES", /* 4 */
105 NULL);
106 }
107}
108
109#if defined(__x86_64__)
110
111/*
112 * Log information about floating point exception handling
113 */
114
115static lck_mtx_t fpxlock;
116
117void
118fpxlog_init(void)
119{
120 lck_grp_attr_t *lck_grp_attr = lck_grp_attr_alloc_init();
121 lck_grp_t *lck_grp = lck_grp_alloc_init("fpx", lck_grp_attr);
122 lck_mtx_init(&fpxlock, lck_grp, LCK_ATTR_NULL);
123}
124
125struct fpx_event {
126 uuid_t fe_uuid;
127 uint32_t fe_code;
128 uint32_t fe_xcpt;
129 TAILQ_ENTRY(fpx_event) fe_link;
130};
131
132static bool
133match_fpx_event(const struct fpx_event *fe,
134 const uuid_t uuid, const uint32_t code, const uint32_t xcpt)
135{
136 return (code == fe->fe_code && xcpt == fe->fe_xcpt &&
137 0 == memcmp(uuid, fe->fe_uuid, sizeof (uuid_t)));
138}
139
140#if FPX_EVENT_DBG
141static __attribute__((noinline)) void
142print_fpx_event(const char *pfx, const struct fpx_event *fe)
143{
144 uuid_string_t uustr;
145 uuid_unparse_upper(fe->fe_uuid, uustr);
146 printf("%s: code 0x%x xcpt 0x%x uuid '%s'\n",
147 pfx, fe->fe_code, fe->fe_xcpt, uustr);
148}
149#define DPRINTF_FPX_EVENT(pfx, fe) print_fpx_event(pfx, fe)
150#else
151#define DPRINTF_FPX_EVENT(pfx, fe) /* nothing */
152#endif
153
154#define MAX_DISTINCT_FPX_EVENTS 101 /* (approx one page of heap) */
155
156/*
157 * Filter to detect "new" <uuid, code, xcpt> tuples.
158 * Uses limited amount of state, managed LRU.
159 * Optimized to ignore repeated invocation with the same tuple.
160 *
161 * Note that there are 6 exception types, two types of FP, and
162 * many binaries, so don't make the list bound too small.
163 * It's also a linear search, so don't make it too large either.
164 * Next level filtering provided by syslogd, and summarization.
165 */
166static bool
167novel_fpx_event(const uuid_t uuid, uint32_t code, uint32_t xcpt)
168{
169 static TAILQ_HEAD(fpx_event_head, fpx_event) fehead =
170 TAILQ_HEAD_INITIALIZER(fehead);
171 struct fpx_event *fe;
172
173 lck_mtx_lock(&fpxlock);
174
175 fe = TAILQ_FIRST(&fehead);
176 if (NULL != fe &&
177 match_fpx_event(fe, uuid, code, xcpt)) {
178 /* seen before and element already at head */
179 lck_mtx_unlock(&fpxlock);
180 DPRINTF_FPX_EVENT("seen, head", fe);
181 return (false);
182 }
183
184 unsigned int count = 0;
185
186 TAILQ_FOREACH(fe, &fehead, fe_link) {
187 if (match_fpx_event(fe, uuid, code, xcpt)) {
188 /* seen before, now move element to head */
189 TAILQ_REMOVE(&fehead, fe, fe_link);
190 TAILQ_INSERT_HEAD(&fehead, fe, fe_link);
191 lck_mtx_unlock(&fpxlock);
192 DPRINTF_FPX_EVENT("seen, moved to head", fe);
193 return (false);
194 }
195 count++;
196 }
197
198 /* not recorded here => novel */
199
200 if (count >= MAX_DISTINCT_FPX_EVENTS) {
201 /* reuse LRU element */
202 fe = TAILQ_LAST(&fehead, fpx_event_head);
203 TAILQ_REMOVE(&fehead, fe, fe_link);
204 DPRINTF_FPX_EVENT("reusing", fe);
205 } else {
206 /* add a new element to the list */
207 fe = kalloc(sizeof (*fe));
208 }
209 memcpy(fe->fe_uuid, uuid, sizeof (uuid_t));
210 fe->fe_code = code;
211 fe->fe_xcpt = xcpt;
212 TAILQ_INSERT_HEAD(&fehead, fe, fe_link);
213 lck_mtx_unlock(&fpxlock);
214
215 DPRINTF_FPX_EVENT("novel", fe);
216
217 return (true);
218}
219
220void
221fpxlog(
222 int code, /* Mach exception code: e.g. 5 or 8 */
223 uint32_t stat, /* Full FP status register bits */
224 uint32_t ctrl, /* Full FP control register bits */
225 uint32_t xcpt) /* Exception bits from FP status */
226{
227 proc_t p = current_proc();
228 if (PROC_NULL == p)
229 return;
230
231 uuid_t uuid;
232 proc_getexecutableuuid(p, uuid, sizeof (uuid));
233
234 /*
235 * Check to see if an exception with this <uuid, code, xcpt>
236 * has been seen before. If "novel" then log a message.
237 */
238 if (!novel_fpx_event(uuid, code, xcpt))
239 return;
240
241 const size_t nmlen = 2 * MAXCOMLEN + 1;
242 char nm[nmlen] = {};
243 proc_selfname(nm, nmlen);
244 if (escape_str(nm, strlen(nm) + 1, nmlen))
245 snprintf(nm, nmlen, "(a.out)");
246
247 const size_t slen = 8 + 1 + 8 + 1;
248 char xcptstr[slen], csrstr[slen];
249
250 snprintf(xcptstr, slen, "%x.%x", code, xcpt);
251 if (ctrl == stat)
252 snprintf(csrstr, slen, "%x", ctrl);
253 else
254 snprintf(csrstr, slen, "%x.%x", ctrl, stat);
255
256#if DEVELOPMENT || DEBUG
257 printf("%s[%d]: com.apple.kernel.fpx: %s, %s\n",
258 nm, proc_pid(p), xcptstr, csrstr);
259#endif
260 kern_asl_msg(LOG_DEBUG, "messagetracer", 5,
261 /* 0 */ "com.apple.message.domain", "com.apple.kernel.fpx",
262 /* 1 */ "com.apple.message.signature", nm,
263 /* 2 */ "com.apple.message.signature2", xcptstr,
264 /* 3 */ "com.apple.message.value", csrstr,
265 /* 4 */ "com.apple.message.summarize", "YES",
266 NULL);
267}
268
269#else
270
271void
272fpxlog_init(void)
273{}
274
275#endif /* __x86_64__ */
276