-
Notifications
You must be signed in to change notification settings - Fork 260
/
kern_core.c
361 lines (325 loc) · 9.29 KB
/
kern_core.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/* $NetBSD: kern_core.c,v 1.35 2021/06/29 22:40:53 dholland Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_sig.c 8.14 (Berkeley) 5/14/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_core.c,v 1.35 2021/06/29 22:40:53 dholland Exp $");
#ifdef _KERNEL_OPT
#include "opt_execfmt.h"
#include "opt_compat_netbsd32.h"
#endif
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/acct.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/proc.h>
#include <sys/exec.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <sys/module.h>
#include <sys/compat_stub.h>
#include <sys/exec_elf.h>
MODULE(MODULE_CLASS_MISC, coredump, NULL);
struct coredump_iostate {
struct lwp *io_lwp;
struct vnode *io_vp;
kauth_cred_t io_cred;
off_t io_offset;
};
static int coredump(struct lwp *, const char *);
static int coredump_buildname(struct proc *, char *, const char *, size_t);
static int coredump_write(struct coredump_iostate *, enum uio_seg segflg,
const void *, size_t);
static off_t coredump_offset(struct coredump_iostate *);
static int
coredump_modcmd(modcmd_t cmd, void *arg)
{
switch (cmd) {
case MODULE_CMD_INIT:
MODULE_HOOK_SET(coredump_hook, coredump);
MODULE_HOOK_SET(coredump_write_hook, coredump_write);
MODULE_HOOK_SET(coredump_offset_hook, coredump_offset);
MODULE_HOOK_SET(coredump_netbsd_hook, real_coredump_netbsd);
#if defined(EXEC_ELF64)
MODULE_HOOK_SET(coredump_elf64_hook, real_coredump_elf64);
#elif defined(EXEC_ELF32)
MODULE_HOOK_SET(coredump_elf32_hook, real_coredump_elf32);
#endif
MODULE_HOOK_SET(uvm_coredump_walkmap_hook,
uvm_coredump_walkmap);
MODULE_HOOK_SET(uvm_coredump_count_segs_hook,
uvm_coredump_count_segs);
return 0;
case MODULE_CMD_FINI:
MODULE_HOOK_UNSET(uvm_coredump_count_segs_hook);
MODULE_HOOK_UNSET(uvm_coredump_walkmap_hook);
#if defined(EXEC_ELF64)
MODULE_HOOK_UNSET(coredump_elf64_hook);
#elif defined(EXEC_ELF32)
MODULE_HOOK_UNSET(coredump_elf32_hook);
#endif
MODULE_HOOK_UNSET(coredump_netbsd_hook);
MODULE_HOOK_UNSET(coredump_offset_hook);
MODULE_HOOK_UNSET(coredump_write_hook);
MODULE_HOOK_UNSET(coredump_hook);
return 0;
default:
return ENOTTY;
}
}
/*
* Dump core, into a file named "progname.core" or "core" (depending on the
* value of shortcorename), unless the process was setuid/setgid.
*/
static int
coredump(struct lwp *l, const char *pattern)
{
struct vnode *vp;
struct proc *p;
struct vmspace *vm;
kauth_cred_t cred;
struct pathbuf *pb;
struct vattr vattr;
struct coredump_iostate io;
struct plimit *lim;
int error, error1;
char *name, *lastslash;
name = PNBUF_GET();
p = l->l_proc;
vm = p->p_vmspace;
mutex_enter(&proc_lock); /* p_session */
mutex_enter(p->p_lock);
/*
* Refuse to core if the data + stack + user size is larger than
* the core dump limit. XXX THIS IS WRONG, because of mapped
* data.
*/
if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >=
p->p_rlimit[RLIMIT_CORE].rlim_cur) {
error = EFBIG; /* better error code? */
mutex_exit(p->p_lock);
mutex_exit(&proc_lock);
goto done;
}
/*
* It may well not be curproc, so grab a reference to its current
* credentials.
*/
kauth_cred_hold(p->p_cred);
cred = p->p_cred;
/*
* Make sure the process has not set-id, to prevent data leaks,
* unless it was specifically requested to allow set-id coredumps.
*/
if (p->p_flag & PK_SUGID) {
if (!security_setidcore_dump) {
error = EPERM;
mutex_exit(p->p_lock);
mutex_exit(&proc_lock);
goto done;
}
pattern = security_setidcore_path;
}
/* Lock, as p_limit and pl_corename might change. */
lim = p->p_limit;
mutex_enter(&lim->pl_lock);
if (pattern == NULL) {
pattern = lim->pl_corename;
}
error = coredump_buildname(p, name, pattern, MAXPATHLEN);
mutex_exit(&lim->pl_lock);
if (error) {
mutex_exit(p->p_lock);
mutex_exit(&proc_lock);
goto done;
}
/*
* On a simple filename, see if the filesystem allow us to write
* core dumps there.
*/
lastslash = strrchr(name, '/');
if (!lastslash) {
vp = p->p_cwdi->cwdi_cdir;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
error = EPERM;
}
mutex_exit(p->p_lock);
mutex_exit(&proc_lock);
if (error)
goto done;
/*
* On a complex filename, see if the filesystem allow us to write
* core dumps there.
*
* XXX: We should have an API that avoids double lookups
*/
if (lastslash) {
char c[2];
if (lastslash - name >= MAXPATHLEN - 2) {
error = EPERM;
goto done;
}
c[0] = lastslash[1];
c[1] = lastslash[2];
lastslash[1] = '.';
lastslash[2] = '\0';
error = namei_simple_kernel(name, NSM_FOLLOW_NOEMULROOT, &vp);
if (error)
goto done;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
error = EPERM;
vrele(vp);
if (error)
goto done;
lastslash[1] = c[0];
lastslash[2] = c[1];
}
pb = pathbuf_create(name);
if (pb == NULL) {
error = ENOMEM;
goto done;
}
error = vn_open(NULL, pb, 0, O_CREAT | O_NOFOLLOW | FWRITE,
S_IRUSR | S_IWUSR, &vp, NULL, NULL);
if (error != 0) {
pathbuf_destroy(pb);
goto done;
}
pathbuf_destroy(pb);
/*
* Don't dump to:
* - non-regular files
* - files with links
* - files we don't own
*/
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1 ||
vattr.va_uid != kauth_cred_geteuid(cred)) {
error = EACCES;
goto out;
}
vattr_null(&vattr);
vattr.va_size = 0;
if ((p->p_flag & PK_SUGID) && security_setidcore_dump) {
vattr.va_uid = security_setidcore_owner;
vattr.va_gid = security_setidcore_group;
vattr.va_mode = security_setidcore_mode;
}
VOP_SETATTR(vp, &vattr, cred);
p->p_acflag |= ACORE;
io.io_lwp = l;
io.io_vp = vp;
io.io_cred = cred;
io.io_offset = 0;
/* Now dump the actual core file. */
error = (*p->p_execsw->es_coredump)(l, &io);
out:
VOP_UNLOCK(vp);
error1 = vn_close(vp, FWRITE, cred);
if (error == 0)
error = error1;
done:
if (name != NULL)
PNBUF_PUT(name);
return error;
}
static int
coredump_buildname(struct proc *p, char *dst, const char *src, size_t len)
{
const char *s;
char *d, *end;
int i;
KASSERT(mutex_owned(&proc_lock));
for (s = src, d = dst, end = d + len; *s != '\0'; s++) {
if (*s == '%') {
switch (*(s + 1)) {
case 'n':
i = snprintf(d, end - d, "%s", p->p_comm);
break;
case 'p':
i = snprintf(d, end - d, "%d", p->p_pid);
break;
case 'u':
i = snprintf(d, end - d, "%.*s",
(int)sizeof p->p_pgrp->pg_session->s_login,
p->p_pgrp->pg_session->s_login);
break;
case 't':
i = snprintf(d, end - d, "%lld",
(long long)p->p_stats->p_start.tv_sec);
break;
default:
goto copy;
}
d += i;
s++;
} else {
copy: *d = *s;
d++;
}
if (d >= end)
return (ENAMETOOLONG);
}
*d = '\0';
return 0;
}
static int
coredump_write(struct coredump_iostate *io, enum uio_seg segflg,
const void *data, size_t len)
{
int error;
error = vn_rdwr(UIO_WRITE, io->io_vp, __UNCONST(data), len,
io->io_offset, segflg,
IO_NODELOCKED|IO_UNIT, io->io_cred, NULL,
segflg == UIO_USERSPACE ? io->io_lwp : NULL);
if (error) {
printf("pid %d (%s): %s write of %zu@%p at %lld failed: %d\n",
io->io_lwp->l_proc->p_pid, io->io_lwp->l_proc->p_comm,
segflg == UIO_USERSPACE ? "user" : "system",
len, data, (long long) io->io_offset, error);
return (error);
}
io->io_offset += len;
return (0);
}
static off_t
coredump_offset(struct coredump_iostate *io)
{
return io->io_offset;
}