1 /* $NetBSD: kern_core.c,v 1.16 2010/06/24 13:03:11 hannken 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 1.16 2010/06/24 13:03:11 hannken Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/vnode.h> 44 #include <sys/namei.h> 45 #include <sys/acct.h> 46 #include <sys/file.h> 47 #include <sys/stat.h> 48 #include <sys/proc.h> 49 #include <sys/exec.h> 50 #include <sys/filedesc.h> 51 #include <sys/kauth.h> 52 #include <sys/module.h> 53 54 MODULE(MODULE_CLASS_MISC, coredump, NULL); 55 56 struct coredump_iostate { 57 struct lwp *io_lwp; 58 struct vnode *io_vp; 59 kauth_cred_t io_cred; 60 off_t io_offset; 61 }; 62 63 static int coredump(struct lwp *, const char *); 64 static int coredump_buildname(struct proc *, char *, const char *, size_t); 65 66 static int 67 coredump_modcmd(modcmd_t cmd, void *arg) 68 { 69 70 switch (cmd) { 71 case MODULE_CMD_INIT: 72 coredump_vec = coredump; 73 return 0; 74 case MODULE_CMD_FINI: 75 /* 76 * In theory we don't need to patch this, as the various 77 * exec formats depend on this module. If this module has 78 * no references, and so can be unloaded, no user programs 79 * can be running and so nothing can call *coredump_vec. 80 */ 81 coredump_vec = (int (*)(struct lwp *, const char *))enosys; 82 return 0; 83 default: 84 return ENOTTY; 85 } 86 } 87 88 /* 89 * Dump core, into a file named "progname.core" or "core" (depending on the 90 * value of shortcorename), unless the process was setuid/setgid. 91 */ 92 static int 93 coredump(struct lwp *l, const char *pattern) 94 { 95 struct vnode *vp; 96 struct proc *p; 97 struct vmspace *vm; 98 kauth_cred_t cred; 99 struct nameidata nd; 100 struct vattr vattr; 101 struct coredump_iostate io; 102 struct plimit *lim; 103 int error, error1; 104 char *name; 105 106 name = PNBUF_GET(); 107 108 p = l->l_proc; 109 vm = p->p_vmspace; 110 111 mutex_enter(proc_lock); /* p_session */ 112 mutex_enter(p->p_lock); 113 114 /* 115 * Refuse to core if the data + stack + user size is larger than 116 * the core dump limit. XXX THIS IS WRONG, because of mapped 117 * data. 118 */ 119 if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >= 120 p->p_rlimit[RLIMIT_CORE].rlim_cur) { 121 error = EFBIG; /* better error code? */ 122 mutex_exit(p->p_lock); 123 mutex_exit(proc_lock); 124 goto done; 125 } 126 127 /* 128 * It may well not be curproc, so grab a reference to its current 129 * credentials. 130 */ 131 kauth_cred_hold(p->p_cred); 132 cred = p->p_cred; 133 134 /* 135 * The core dump will go in the current working directory. Make 136 * sure that the directory is still there and that the mount flags 137 * allow us to write core dumps there. 138 * 139 * XXX: this is partially bogus, it should be checking the directory 140 * into which the file is actually written - which probably needs 141 * a flag on namei() 142 */ 143 vp = p->p_cwdi->cwdi_cdir; 144 if (vp->v_mount == NULL || 145 (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) { 146 error = EPERM; 147 mutex_exit(p->p_lock); 148 mutex_exit(proc_lock); 149 goto done; 150 } 151 152 /* 153 * Make sure the process has not set-id, to prevent data leaks, 154 * unless it was specifically requested to allow set-id coredumps. 155 */ 156 if (p->p_flag & PK_SUGID) { 157 if (!security_setidcore_dump) { 158 error = EPERM; 159 mutex_exit(p->p_lock); 160 mutex_exit(proc_lock); 161 goto done; 162 } 163 pattern = security_setidcore_path; 164 } 165 166 /* It is (just) possible for p_limit and pl_corename to change */ 167 lim = p->p_limit; 168 mutex_enter(&lim->pl_lock); 169 if (pattern == NULL) 170 pattern = lim->pl_corename; 171 error = coredump_buildname(p, name, pattern, MAXPATHLEN); 172 mutex_exit(&lim->pl_lock); 173 mutex_exit(p->p_lock); 174 mutex_exit(proc_lock); 175 if (error) 176 goto done; 177 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); 178 if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, 179 S_IRUSR | S_IWUSR)) != 0) 180 goto done; 181 vp = nd.ni_vp; 182 183 /* Don't dump to non-regular files or files with links. */ 184 if (vp->v_type != VREG || 185 VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1) { 186 error = EINVAL; 187 goto out; 188 } 189 vattr_null(&vattr); 190 vattr.va_size = 0; 191 192 if ((p->p_flag & PK_SUGID) && security_setidcore_dump) { 193 vattr.va_uid = security_setidcore_owner; 194 vattr.va_gid = security_setidcore_group; 195 vattr.va_mode = security_setidcore_mode; 196 } 197 198 VOP_SETATTR(vp, &vattr, cred); 199 p->p_acflag |= ACORE; 200 201 io.io_lwp = l; 202 io.io_vp = vp; 203 io.io_cred = cred; 204 io.io_offset = 0; 205 206 /* Now dump the actual core file. */ 207 error = (*p->p_execsw->es_coredump)(l, &io); 208 out: 209 VOP_UNLOCK(vp); 210 error1 = vn_close(vp, FWRITE, cred); 211 if (error == 0) 212 error = error1; 213 done: 214 if (name != NULL) 215 PNBUF_PUT(name); 216 return error; 217 } 218 219 static int 220 coredump_buildname(struct proc *p, char *dst, const char *src, size_t len) 221 { 222 const char *s; 223 char *d, *end; 224 int i; 225 226 KASSERT(mutex_owned(proc_lock)); 227 228 for (s = src, d = dst, end = d + len; *s != '\0'; s++) { 229 if (*s == '%') { 230 switch (*(s + 1)) { 231 case 'n': 232 i = snprintf(d, end - d, "%s", p->p_comm); 233 break; 234 case 'p': 235 i = snprintf(d, end - d, "%d", p->p_pid); 236 break; 237 case 'u': 238 i = snprintf(d, end - d, "%.*s", 239 (int)sizeof p->p_pgrp->pg_session->s_login, 240 p->p_pgrp->pg_session->s_login); 241 break; 242 case 't': 243 i = snprintf(d, end - d, "%lld", 244 (long long)p->p_stats->p_start.tv_sec); 245 break; 246 default: 247 goto copy; 248 } 249 d += i; 250 s++; 251 } else { 252 copy: *d = *s; 253 d++; 254 } 255 if (d >= end) 256 return (ENAMETOOLONG); 257 } 258 *d = '\0'; 259 return 0; 260 } 261 262 int 263 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 264 { 265 struct coredump_iostate *io = cookie; 266 int error; 267 268 error = vn_rdwr(UIO_WRITE, io->io_vp, __UNCONST(data), len, 269 io->io_offset, segflg, 270 IO_NODELOCKED|IO_UNIT, io->io_cred, NULL, 271 segflg == UIO_USERSPACE ? io->io_lwp : NULL); 272 if (error) { 273 printf("pid %d (%s): %s write of %zu@%p at %lld failed: %d\n", 274 io->io_lwp->l_proc->p_pid, io->io_lwp->l_proc->p_comm, 275 segflg == UIO_USERSPACE ? "user" : "system", 276 len, data, (long long) io->io_offset, error); 277 return (error); 278 } 279 280 io->io_offset += len; 281 return (0); 282 } 283