1 /* $NetBSD: kern_core.c,v 1.8 2007/12/08 19:29:47 pooka 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 1.8 2007/12/08 19:29:47 pooka Exp $"); 41 42 #include "opt_coredump.h" 43 44 #include <sys/param.h> 45 #include <sys/vnode.h> 46 #include <sys/namei.h> 47 #include <sys/acct.h> 48 #include <sys/file.h> 49 #include <sys/stat.h> 50 #include <sys/proc.h> 51 #include <sys/exec.h> 52 #include <sys/filedesc.h> 53 #include <sys/kauth.h> 54 55 #if !defined(COREDUMP) 56 57 int 58 coredump(struct lwp *l, const char *pattern) 59 { 60 61 return (ENOSYS); 62 } 63 64 #else /* COREDUMP */ 65 66 struct coredump_iostate { 67 struct lwp *io_lwp; 68 struct vnode *io_vp; 69 kauth_cred_t io_cred; 70 off_t io_offset; 71 }; 72 73 static int coredump_buildname(struct proc *, char *, const char *, size_t); 74 75 /* 76 * Dump core, into a file named "progname.core" or "core" (depending on the 77 * value of shortcorename), unless the process was setuid/setgid. 78 */ 79 int 80 coredump(struct lwp *l, const char *pattern) 81 { 82 struct vnode *vp; 83 struct proc *p; 84 struct vmspace *vm; 85 kauth_cred_t cred; 86 struct nameidata nd; 87 struct vattr vattr; 88 struct coredump_iostate io; 89 struct plimit *lim; 90 int error, error1; 91 char *name; 92 93 name = PNBUF_GET(); 94 95 p = l->l_proc; 96 vm = p->p_vmspace; 97 98 mutex_enter(&proclist_lock); /* p_session */ 99 mutex_enter(&p->p_mutex); 100 101 /* 102 * Refuse to core if the data + stack + user size is larger than 103 * the core dump limit. XXX THIS IS WRONG, because of mapped 104 * data. 105 */ 106 if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >= 107 p->p_rlimit[RLIMIT_CORE].rlim_cur) { 108 error = EFBIG; /* better error code? */ 109 mutex_exit(&p->p_mutex); 110 mutex_exit(&proclist_lock); 111 goto done; 112 } 113 114 /* 115 * It may well not be curproc, so grab a reference to its current 116 * credentials. 117 */ 118 kauth_cred_hold(p->p_cred); 119 cred = p->p_cred; 120 121 /* 122 * The core dump will go in the current working directory. Make 123 * sure that the directory is still there and that the mount flags 124 * allow us to write core dumps there. 125 * 126 * XXX: this is partially bogus, it should be checking the directory 127 * into which the file is actually written - which probably needs 128 * a flag on namei() 129 */ 130 vp = p->p_cwdi->cwdi_cdir; 131 if (vp->v_mount == NULL || 132 (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) { 133 error = EPERM; 134 mutex_exit(&p->p_mutex); 135 mutex_exit(&proclist_lock); 136 goto done; 137 } 138 139 /* 140 * Make sure the process has not set-id, to prevent data leaks, 141 * unless it was specifically requested to allow set-id coredumps. 142 */ 143 if (p->p_flag & PK_SUGID) { 144 if (!security_setidcore_dump) { 145 error = EPERM; 146 mutex_exit(&p->p_mutex); 147 mutex_exit(&proclist_lock); 148 goto done; 149 } 150 pattern = security_setidcore_path; 151 } 152 153 /* It is (just) possible for p_limit and pl_corename to change */ 154 lim = p->p_limit; 155 mutex_enter(&lim->pl_lock); 156 if (pattern == NULL) 157 pattern = lim->pl_corename; 158 error = coredump_buildname(p, name, pattern, MAXPATHLEN); 159 mutex_exit(&lim->pl_lock); 160 mutex_exit(&p->p_mutex); 161 mutex_exit(&proclist_lock); 162 if (error) 163 goto done; 164 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); 165 if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, 166 S_IRUSR | S_IWUSR)) != 0) 167 goto done; 168 vp = nd.ni_vp; 169 170 /* Don't dump to non-regular files or files with links. */ 171 if (vp->v_type != VREG || 172 VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1) { 173 error = EINVAL; 174 goto out; 175 } 176 VATTR_NULL(&vattr); 177 vattr.va_size = 0; 178 179 if ((p->p_flag & PK_SUGID) && security_setidcore_dump) { 180 vattr.va_uid = security_setidcore_owner; 181 vattr.va_gid = security_setidcore_group; 182 vattr.va_mode = security_setidcore_mode; 183 } 184 185 VOP_LEASE(vp, cred, LEASE_WRITE); 186 VOP_SETATTR(vp, &vattr, cred); 187 p->p_acflag |= ACORE; 188 189 io.io_lwp = l; 190 io.io_vp = vp; 191 io.io_cred = cred; 192 io.io_offset = 0; 193 194 /* Now dump the actual core file. */ 195 error = (*p->p_execsw->es_coredump)(l, &io); 196 out: 197 VOP_UNLOCK(vp, 0); 198 error1 = vn_close(vp, FWRITE, cred, l); 199 if (error == 0) 200 error = error1; 201 done: 202 if (name != NULL) 203 PNBUF_PUT(name); 204 return error; 205 } 206 207 static int 208 coredump_buildname(struct proc *p, char *dst, const char *src, size_t len) 209 { 210 const char *s; 211 char *d, *end; 212 int i; 213 214 KASSERT(mutex_owned(&proclist_lock)); 215 216 for (s = src, d = dst, end = d + len; *s != '\0'; s++) { 217 if (*s == '%') { 218 switch (*(s + 1)) { 219 case 'n': 220 i = snprintf(d, end - d, "%s", p->p_comm); 221 break; 222 case 'p': 223 i = snprintf(d, end - d, "%d", p->p_pid); 224 break; 225 case 'u': 226 i = snprintf(d, end - d, "%.*s", 227 (int)sizeof p->p_pgrp->pg_session->s_login, 228 p->p_pgrp->pg_session->s_login); 229 break; 230 case 't': 231 i = snprintf(d, end - d, "%ld", 232 p->p_stats->p_start.tv_sec); 233 break; 234 default: 235 goto copy; 236 } 237 d += i; 238 s++; 239 } else { 240 copy: *d = *s; 241 d++; 242 } 243 if (d >= end) 244 return (ENAMETOOLONG); 245 } 246 *d = '\0'; 247 return 0; 248 } 249 250 int 251 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 252 { 253 struct coredump_iostate *io = cookie; 254 int error; 255 256 error = vn_rdwr(UIO_WRITE, io->io_vp, __UNCONST(data), len, 257 io->io_offset, segflg, 258 IO_NODELOCKED|IO_UNIT, io->io_cred, NULL, 259 segflg == UIO_USERSPACE ? io->io_lwp : NULL); 260 if (error) { 261 printf("pid %d (%s): %s write of %zu@%p at %lld failed: %d\n", 262 io->io_lwp->l_proc->p_pid, io->io_lwp->l_proc->p_comm, 263 segflg == UIO_USERSPACE ? "user" : "system", 264 len, data, (long long) io->io_offset, error); 265 return (error); 266 } 267 268 io->io_offset += len; 269 return (0); 270 } 271 272 #endif /* COREDUMP */ 273