kern_core.c revision 1.33.2.1
1 /* $NetBSD: kern_core.c,v 1.33.2.1 2020/12/14 14:38:13 thorpej Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 37 */ 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: kern_core.c,v 1.33.2.1 2020/12/14 14:38:13 thorpej Exp $"); 41 42 #ifdef _KERNEL_OPT 43 #include "opt_execfmt.h" 44 #include "opt_compat_netbsd32.h" 45 #endif 46 47 #include <sys/param.h> 48 #include <sys/vnode.h> 49 #include <sys/namei.h> 50 #include <sys/acct.h> 51 #include <sys/file.h> 52 #include <sys/stat.h> 53 #include <sys/proc.h> 54 #include <sys/exec.h> 55 #include <sys/filedesc.h> 56 #include <sys/kauth.h> 57 #include <sys/module.h> 58 #include <sys/compat_stub.h> 59 #include <sys/exec_elf.h> 60 61 MODULE(MODULE_CLASS_MISC, coredump, NULL); 62 63 struct coredump_iostate { 64 struct lwp *io_lwp; 65 struct vnode *io_vp; 66 kauth_cred_t io_cred; 67 off_t io_offset; 68 }; 69 70 static int coredump(struct lwp *, const char *); 71 static int coredump_buildname(struct proc *, char *, const char *, size_t); 72 static int coredump_write(struct coredump_iostate *, enum uio_seg segflg, 73 const void *, size_t); 74 static off_t coredump_offset(struct coredump_iostate *); 75 76 static int 77 coredump_modcmd(modcmd_t cmd, void *arg) 78 { 79 80 switch (cmd) { 81 case MODULE_CMD_INIT: 82 MODULE_HOOK_SET(coredump_hook, coredump); 83 MODULE_HOOK_SET(coredump_write_hook, coredump_write); 84 MODULE_HOOK_SET(coredump_offset_hook, coredump_offset); 85 MODULE_HOOK_SET(coredump_netbsd_hook, real_coredump_netbsd); 86 #if defined(EXEC_ELF64) 87 MODULE_HOOK_SET(coredump_elf64_hook, real_coredump_elf64); 88 #elif defined(EXEC_ELF32) 89 MODULE_HOOK_SET(coredump_elf32_hook, real_coredump_elf32); 90 #endif 91 MODULE_HOOK_SET(uvm_coredump_walkmap_hook, 92 uvm_coredump_walkmap); 93 MODULE_HOOK_SET(uvm_coredump_count_segs_hook, 94 uvm_coredump_count_segs); 95 return 0; 96 case MODULE_CMD_FINI: 97 MODULE_HOOK_UNSET(uvm_coredump_count_segs_hook); 98 MODULE_HOOK_UNSET(uvm_coredump_walkmap_hook); 99 #if defined(EXEC_ELF64) 100 MODULE_HOOK_UNSET(coredump_elf64_hook); 101 #elif defined(EXEC_ELF32) 102 MODULE_HOOK_UNSET(coredump_elf32_hook); 103 #endif 104 MODULE_HOOK_UNSET(coredump_netbsd_hook); 105 MODULE_HOOK_UNSET(coredump_offset_hook); 106 MODULE_HOOK_UNSET(coredump_write_hook); 107 MODULE_HOOK_UNSET(coredump_hook); 108 return 0; 109 default: 110 return ENOTTY; 111 } 112 } 113 114 /* 115 * Dump core, into a file named "progname.core" or "core" (depending on the 116 * value of shortcorename), unless the process was setuid/setgid. 117 */ 118 static int 119 coredump(struct lwp *l, const char *pattern) 120 { 121 struct vnode *vp; 122 struct proc *p; 123 struct vmspace *vm; 124 kauth_cred_t cred; 125 struct pathbuf *pb; 126 struct nameidata nd; 127 struct vattr vattr; 128 struct coredump_iostate io; 129 struct plimit *lim; 130 int error, error1; 131 char *name, *lastslash; 132 133 name = PNBUF_GET(); 134 135 p = l->l_proc; 136 vm = p->p_vmspace; 137 138 mutex_enter(&proc_lock); /* p_session */ 139 mutex_enter(p->p_lock); 140 141 /* 142 * Refuse to core if the data + stack + user size is larger than 143 * the core dump limit. XXX THIS IS WRONG, because of mapped 144 * data. 145 */ 146 if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >= 147 p->p_rlimit[RLIMIT_CORE].rlim_cur) { 148 error = EFBIG; /* better error code? */ 149 mutex_exit(p->p_lock); 150 mutex_exit(&proc_lock); 151 goto done; 152 } 153 154 /* 155 * It may well not be curproc, so grab a reference to its current 156 * credentials. 157 */ 158 kauth_cred_hold(p->p_cred); 159 cred = p->p_cred; 160 161 /* 162 * Make sure the process has not set-id, to prevent data leaks, 163 * unless it was specifically requested to allow set-id coredumps. 164 */ 165 if (p->p_flag & PK_SUGID) { 166 if (!security_setidcore_dump) { 167 error = EPERM; 168 mutex_exit(p->p_lock); 169 mutex_exit(&proc_lock); 170 goto done; 171 } 172 pattern = security_setidcore_path; 173 } 174 175 /* Lock, as p_limit and pl_corename might change. */ 176 lim = p->p_limit; 177 mutex_enter(&lim->pl_lock); 178 if (pattern == NULL) { 179 pattern = lim->pl_corename; 180 } 181 error = coredump_buildname(p, name, pattern, MAXPATHLEN); 182 mutex_exit(&lim->pl_lock); 183 184 if (error) { 185 mutex_exit(p->p_lock); 186 mutex_exit(&proc_lock); 187 goto done; 188 } 189 190 /* 191 * On a simple filename, see if the filesystem allow us to write 192 * core dumps there. 193 */ 194 lastslash = strrchr(name, '/'); 195 if (!lastslash) { 196 vp = p->p_cwdi->cwdi_cdir; 197 if (vp->v_mount == NULL || 198 (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) 199 error = EPERM; 200 } 201 202 mutex_exit(p->p_lock); 203 mutex_exit(&proc_lock); 204 if (error) 205 goto done; 206 207 /* 208 * On a complex filename, see if the filesystem allow us to write 209 * core dumps there. 210 * 211 * XXX: We should have an API that avoids double lookups 212 */ 213 if (lastslash) { 214 char c[2]; 215 216 if (lastslash - name >= MAXPATHLEN - 2) { 217 error = EPERM; 218 goto done; 219 } 220 221 c[0] = lastslash[1]; 222 c[1] = lastslash[2]; 223 lastslash[1] = '.'; 224 lastslash[2] = '\0'; 225 error = namei_simple_kernel(name, NSM_FOLLOW_NOEMULROOT, &vp); 226 if (error) 227 goto done; 228 if (vp->v_mount == NULL || 229 (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) 230 error = EPERM; 231 vrele(vp); 232 if (error) 233 goto done; 234 lastslash[1] = c[0]; 235 lastslash[2] = c[1]; 236 } 237 238 pb = pathbuf_create(name); 239 if (pb == NULL) { 240 error = ENOMEM; 241 goto done; 242 } 243 NDINIT(&nd, LOOKUP, NOFOLLOW, pb); 244 if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, 245 S_IRUSR | S_IWUSR)) != 0) { 246 pathbuf_destroy(pb); 247 goto done; 248 } 249 vp = nd.ni_vp; 250 pathbuf_destroy(pb); 251 252 /* 253 * Don't dump to: 254 * - non-regular files 255 * - files with links 256 * - files we don't own 257 */ 258 if (vp->v_type != VREG || 259 VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1 || 260 vattr.va_uid != kauth_cred_geteuid(cred)) { 261 error = EACCES; 262 goto out; 263 } 264 vattr_null(&vattr); 265 vattr.va_size = 0; 266 267 if ((p->p_flag & PK_SUGID) && security_setidcore_dump) { 268 vattr.va_uid = security_setidcore_owner; 269 vattr.va_gid = security_setidcore_group; 270 vattr.va_mode = security_setidcore_mode; 271 } 272 273 VOP_SETATTR(vp, &vattr, cred); 274 p->p_acflag |= ACORE; 275 276 io.io_lwp = l; 277 io.io_vp = vp; 278 io.io_cred = cred; 279 io.io_offset = 0; 280 281 /* Now dump the actual core file. */ 282 error = (*p->p_execsw->es_coredump)(l, &io); 283 out: 284 VOP_UNLOCK(vp); 285 error1 = vn_close(vp, FWRITE, cred); 286 if (error == 0) 287 error = error1; 288 done: 289 if (name != NULL) 290 PNBUF_PUT(name); 291 return error; 292 } 293 294 static int 295 coredump_buildname(struct proc *p, char *dst, const char *src, size_t len) 296 { 297 const char *s; 298 char *d, *end; 299 int i; 300 301 KASSERT(mutex_owned(&proc_lock)); 302 303 for (s = src, d = dst, end = d + len; *s != '\0'; s++) { 304 if (*s == '%') { 305 switch (*(s + 1)) { 306 case 'n': 307 i = snprintf(d, end - d, "%s", p->p_comm); 308 break; 309 case 'p': 310 i = snprintf(d, end - d, "%d", p->p_pid); 311 break; 312 case 'u': 313 i = snprintf(d, end - d, "%.*s", 314 (int)sizeof p->p_pgrp->pg_session->s_login, 315 p->p_pgrp->pg_session->s_login); 316 break; 317 case 't': 318 i = snprintf(d, end - d, "%lld", 319 (long long)p->p_stats->p_start.tv_sec); 320 break; 321 default: 322 goto copy; 323 } 324 d += i; 325 s++; 326 } else { 327 copy: *d = *s; 328 d++; 329 } 330 if (d >= end) 331 return (ENAMETOOLONG); 332 } 333 *d = '\0'; 334 return 0; 335 } 336 337 static int 338 coredump_write(struct coredump_iostate *io, enum uio_seg segflg, 339 const void *data, size_t len) 340 { 341 int error; 342 343 error = vn_rdwr(UIO_WRITE, io->io_vp, __UNCONST(data), len, 344 io->io_offset, segflg, 345 IO_NODELOCKED|IO_UNIT, io->io_cred, NULL, 346 segflg == UIO_USERSPACE ? io->io_lwp : NULL); 347 if (error) { 348 printf("pid %d (%s): %s write of %zu@%p at %lld failed: %d\n", 349 io->io_lwp->l_proc->p_pid, io->io_lwp->l_proc->p_comm, 350 segflg == UIO_USERSPACE ? "user" : "system", 351 len, data, (long long) io->io_offset, error); 352 return (error); 353 } 354 355 io->io_offset += len; 356 return (0); 357 } 358 359 static off_t 360 coredump_offset(struct coredump_iostate *io) 361 { 362 return io->io_offset; 363 } 364
Indexes created Wed Sep 24 05:09:52 GMT 2025