1 /* $OpenBSD: sys_process.c,v 1.25 2003/06/02 23:28:06 millert Exp $ */ 2 /* $NetBSD: sys_process.c,v 1.55 1996/05/15 06:17:47 tls Exp $ */ 3 4 /*- 5 * Copyright (c) 1994 Christopher G. Demetriou. All rights reserved. 6 * Copyright (c) 1982, 1986, 1989, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93 39 */ 40 41 /* 42 * References: 43 * (1) Bach's "The Design of the UNIX Operating System", 44 * (2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution, 45 * (3) the "4.4BSD Programmer's Reference Manual" published 46 * by USENIX and O'Reilly & Associates. 47 * The 4.4BSD PRM does a reasonably good job of documenting what the various 48 * ptrace() requests should actually do, and its text is quoted several times 49 * in this file. 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/proc.h> 55 #include <sys/signalvar.h> 56 #include <sys/errno.h> 57 #include <sys/ptrace.h> 58 #include <sys/uio.h> 59 #include <sys/user.h> 60 61 #include <sys/mount.h> 62 #include <sys/syscallargs.h> 63 64 #include <uvm/uvm_extern.h> 65 66 #include <machine/reg.h> 67 68 #include <miscfs/procfs/procfs.h> 69 70 /* 71 * Process debugging system call. 72 */ 73 int 74 sys_ptrace(p, v, retval) 75 struct proc *p; 76 void *v; 77 register_t *retval; 78 { 79 struct sys_ptrace_args /* { 80 syscallarg(int) req; 81 syscallarg(pid_t) pid; 82 syscallarg(caddr_t) addr; 83 syscallarg(int) data; 84 } */ *uap = v; 85 struct proc *t; /* target process */ 86 struct uio uio; 87 struct iovec iov; 88 struct ptrace_io_desc piod; 89 int error, write; 90 int temp; 91 92 /* "A foolish consistency..." XXX */ 93 if (SCARG(uap, req) == PT_TRACE_ME) 94 t = p; 95 else { 96 97 /* Find the process we're supposed to be operating on. */ 98 if ((t = pfind(SCARG(uap, pid))) == NULL) 99 return (ESRCH); 100 } 101 102 if ((t->p_flag & P_INEXEC) != 0) 103 return (EAGAIN); 104 105 /* Make sure we can operate on it. */ 106 switch (SCARG(uap, req)) { 107 case PT_TRACE_ME: 108 /* Saying that you're being traced is always legal. */ 109 break; 110 111 case PT_ATTACH: 112 /* 113 * You can't attach to a process if: 114 * (1) it's the process that's doing the attaching, 115 */ 116 if (t->p_pid == p->p_pid) 117 return (EINVAL); 118 119 /* 120 * (2) it's a system process 121 */ 122 if (ISSET(t->p_flag, P_SYSTEM)) 123 return (EPERM); 124 125 /* 126 * (3) it's already being traced, or 127 */ 128 if (ISSET(t->p_flag, P_TRACED)) 129 return (EBUSY); 130 131 /* 132 * (4) it's not owned by you, or the last exec 133 * gave us setuid/setgid privs (unless 134 * you're root), or... 135 * 136 * [Note: once P_SUGID or P_SUGIDEXEC gets set in 137 * execve(), they stay set until the process does 138 * another execve(). Hence this prevents a setuid 139 * process which revokes it's special privileges using 140 * setuid() from being traced. This is good security.] 141 */ 142 if ((t->p_cred->p_ruid != p->p_cred->p_ruid || 143 ISSET(t->p_flag, P_SUGIDEXEC) || 144 ISSET(t->p_flag, P_SUGID)) && 145 (error = suser(p->p_ucred, &p->p_acflag)) != 0) 146 return (error); 147 148 /* 149 * (5) ...it's init, which controls the security level 150 * of the entire system, and the system was not 151 * compiled with permanently insecure mode turned 152 * on. 153 */ 154 if ((t->p_pid == 1) && (securelevel > -1)) 155 return (EPERM); 156 break; 157 158 case PT_READ_I: 159 case PT_READ_D: 160 case PT_WRITE_I: 161 case PT_WRITE_D: 162 case PT_IO: 163 case PT_CONTINUE: 164 case PT_KILL: 165 case PT_DETACH: 166 #ifdef PT_STEP 167 case PT_STEP: 168 #endif 169 case PT_GETREGS: 170 case PT_SETREGS: 171 #ifdef PT_GETFPREGS 172 case PT_GETFPREGS: 173 #endif 174 #ifdef PT_SETFPREGS 175 case PT_SETFPREGS: 176 #endif 177 /* 178 * You can't do what you want to the process if: 179 * (1) It's not being traced at all, 180 */ 181 if (!ISSET(t->p_flag, P_TRACED)) 182 return (EPERM); 183 184 /* 185 * (2) it's not being traced by _you_, or 186 */ 187 if (t->p_pptr != p) 188 return (EBUSY); 189 190 /* 191 * (3) it's not currently stopped. 192 */ 193 if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) 194 return (EBUSY); 195 break; 196 197 default: /* It was not a legal request. */ 198 return (EINVAL); 199 } 200 201 /* Do single-step fixup if needed. */ 202 FIX_SSTEP(t); 203 204 /* Now do the operation. */ 205 write = 0; 206 *retval = 0; 207 208 switch (SCARG(uap, req)) { 209 case PT_TRACE_ME: 210 /* Just set the trace flag. */ 211 SET(t->p_flag, P_TRACED); 212 t->p_oppid = t->p_pptr->p_pid; 213 return (0); 214 215 case PT_WRITE_I: /* XXX no separate I and D spaces */ 216 case PT_WRITE_D: 217 write = 1; 218 temp = SCARG(uap, data); 219 case PT_READ_I: /* XXX no separate I and D spaces */ 220 case PT_READ_D: 221 /* write = 0 done above. */ 222 iov.iov_base = (caddr_t)&temp; 223 iov.iov_len = sizeof(int); 224 uio.uio_iov = &iov; 225 uio.uio_iovcnt = 1; 226 uio.uio_offset = (off_t)(long)SCARG(uap, addr); 227 uio.uio_resid = sizeof(int); 228 uio.uio_segflg = UIO_SYSSPACE; 229 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 230 uio.uio_procp = p; 231 error = procfs_domem(p, t, NULL, &uio); 232 if (write == 0) 233 *retval = temp; 234 return (error); 235 case PT_IO: 236 error = copyin(SCARG(uap, addr), &piod, sizeof(piod)); 237 if (error) 238 return (error); 239 iov.iov_base = piod.piod_addr; 240 iov.iov_len = piod.piod_len; 241 uio.uio_iov = &iov; 242 uio.uio_iovcnt = 1; 243 uio.uio_offset = (off_t)(long)piod.piod_offs; 244 uio.uio_resid = piod.piod_len; 245 uio.uio_segflg = UIO_USERSPACE; 246 uio.uio_procp = p; 247 switch (piod.piod_op) { 248 case PIOD_READ_D: 249 case PIOD_READ_I: 250 uio.uio_rw = UIO_READ; 251 break; 252 case PIOD_WRITE_D: 253 case PIOD_WRITE_I: 254 uio.uio_rw = UIO_WRITE; 255 break; 256 default: 257 return (EINVAL); 258 } 259 error = procfs_domem(p, t, NULL, &uio); 260 piod.piod_len -= uio.uio_resid; 261 (void) copyout(&piod, SCARG(uap, addr), sizeof(piod)); 262 return (error); 263 #ifdef PT_STEP 264 case PT_STEP: 265 /* 266 * From the 4.4BSD PRM: 267 * "Execution continues as in request PT_CONTINUE; however 268 * as soon as possible after execution of at least one 269 * instruction, execution stops again. [ ... ]" 270 */ 271 #endif 272 case PT_CONTINUE: 273 /* 274 * From the 4.4BSD PRM: 275 * "The data argument is taken as a signal number and the 276 * child's execution continues at location addr as if it 277 * incurred that signal. Normally the signal number will 278 * be either 0 to indicate that the signal that caused the 279 * stop should be ignored, or that value fetched out of 280 * the process's image indicating which signal caused 281 * the stop. If addr is (int *)1 then execution continues 282 * from where it stopped." 283 */ 284 285 /* Check that the data is a valid signal number or zero. */ 286 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 287 return (EINVAL); 288 289 PHOLD(t); 290 /* If the address paramter is not (int *)1, set the pc. */ 291 if ((int *)SCARG(uap, addr) != (int *)1) 292 if ((error = process_set_pc(t, SCARG(uap, addr))) != 0) 293 goto relebad; 294 295 #ifdef PT_STEP 296 /* 297 * Arrange for a single-step, if that's requested and possible. 298 */ 299 error = process_sstep(t, SCARG(uap, req) == PT_STEP); 300 if (error) 301 goto relebad; 302 #endif 303 PRELE(t); 304 goto sendsig; 305 306 case PT_DETACH: 307 /* 308 * From the 4.4BSD PRM: 309 * "The data argument is taken as a signal number and the 310 * child's execution continues at location addr as if it 311 * incurred that signal. Normally the signal number will 312 * be either 0 to indicate that the signal that caused the 313 * stop should be ignored, or that value fetched out of 314 * the process's image indicating which signal caused 315 * the stop. If addr is (int *)1 then execution continues 316 * from where it stopped." 317 */ 318 319 /* Check that the data is a valid signal number or zero. */ 320 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 321 return (EINVAL); 322 323 PHOLD(t); 324 #ifdef PT_STEP 325 /* 326 * Arrange for a single-step, if that's requested and possible. 327 */ 328 error = process_sstep(t, SCARG(uap, req) == PT_STEP); 329 if (error) 330 goto relebad; 331 #endif 332 PRELE(t); 333 334 /* give process back to original parent or init */ 335 if (t->p_oppid != t->p_pptr->p_pid) { 336 struct proc *pp; 337 338 pp = pfind(t->p_oppid); 339 proc_reparent(t, pp ? pp : initproc); 340 } 341 342 /* not being traced any more */ 343 t->p_oppid = 0; 344 CLR(t->p_flag, P_TRACED|P_WAITED); 345 346 sendsig: 347 /* Finally, deliver the requested signal (or none). */ 348 if (t->p_stat == SSTOP) { 349 t->p_xstat = SCARG(uap, data); 350 setrunnable(t); 351 } else { 352 if (SCARG(uap, data) != 0) 353 psignal(t, SCARG(uap, data)); 354 } 355 return (0); 356 357 relebad: 358 PRELE(t); 359 return (error); 360 361 case PT_KILL: 362 /* just send the process a KILL signal. */ 363 SCARG(uap, data) = SIGKILL; 364 goto sendsig; /* in PT_CONTINUE, above. */ 365 366 case PT_ATTACH: 367 /* 368 * As done in procfs: 369 * Go ahead and set the trace flag. 370 * Save the old parent (it's reset in 371 * _DETACH, and also in kern_exit.c:wait4() 372 * Reparent the process so that the tracing 373 * proc gets to see all the action. 374 * Stop the target. 375 */ 376 SET(t->p_flag, P_TRACED); 377 t->p_oppid = t->p_pptr->p_pid; 378 if (t->p_pptr != p) 379 proc_reparent(t, p); 380 SCARG(uap, data) = SIGSTOP; 381 goto sendsig; 382 383 case PT_SETREGS: 384 write = 1; 385 case PT_GETREGS: 386 /* write = 0 done above. */ 387 if (!procfs_validregs(t, NULL)) 388 return (EINVAL); 389 else { 390 iov.iov_base = SCARG(uap, addr); 391 iov.iov_len = sizeof(struct reg); 392 uio.uio_iov = &iov; 393 uio.uio_iovcnt = 1; 394 uio.uio_offset = 0; 395 uio.uio_resid = sizeof(struct reg); 396 uio.uio_segflg = UIO_USERSPACE; 397 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 398 uio.uio_procp = p; 399 return (procfs_doregs(p, t, NULL, &uio)); 400 } 401 #ifdef PT_SETFPREGS 402 case PT_SETFPREGS: 403 write = 1; 404 #endif 405 #ifdef PT_GETFPREGS 406 case PT_GETFPREGS: 407 /* write = 0 done above. */ 408 #endif 409 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 410 if (!procfs_validfpregs(t, NULL)) 411 return (EINVAL); 412 else { 413 iov.iov_base = SCARG(uap, addr); 414 iov.iov_len = sizeof(struct fpreg); 415 uio.uio_iov = &iov; 416 uio.uio_iovcnt = 1; 417 uio.uio_offset = 0; 418 uio.uio_resid = sizeof(struct fpreg); 419 uio.uio_segflg = UIO_USERSPACE; 420 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 421 uio.uio_procp = p; 422 return (procfs_dofpregs(p, t, NULL, &uio)); 423 } 424 #endif 425 } 426 427 #ifdef DIAGNOSTIC 428 panic("ptrace: impossible"); 429 #endif 430 return 0; 431 } 432