1 /* $NetBSD: kern_exec.c,v 1.110 2000/05/27 00:40:45 sommerfeld Exp $ */ 2 3 /*- 4 * Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou 5 * Copyright (C) 1992 Wolfgang Solfrank. 6 * Copyright (C) 1992 TooLs GmbH. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by TooLs GmbH. 20 * 4. The name of TooLs GmbH may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 #include "opt_ktrace.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/filedesc.h> 40 #include <sys/kernel.h> 41 #include <sys/proc.h> 42 #include <sys/mount.h> 43 #include <sys/malloc.h> 44 #include <sys/namei.h> 45 #include <sys/vnode.h> 46 #include <sys/file.h> 47 #include <sys/acct.h> 48 #include <sys/exec.h> 49 #include <sys/ktrace.h> 50 #include <sys/resourcevar.h> 51 #include <sys/wait.h> 52 #include <sys/mman.h> 53 #include <sys/signalvar.h> 54 #include <sys/stat.h> 55 56 #include <sys/syscallargs.h> 57 58 #include <vm/vm.h> 59 #include <vm/vm_kern.h> 60 61 #include <uvm/uvm_extern.h> 62 63 #include <machine/cpu.h> 64 #include <machine/reg.h> 65 66 /* 67 * check exec: 68 * given an "executable" described in the exec package's namei info, 69 * see what we can do with it. 70 * 71 * ON ENTRY: 72 * exec package with appropriate namei info 73 * proc pointer of exec'ing proc 74 * NO SELF-LOCKED VNODES 75 * 76 * ON EXIT: 77 * error: nothing held, etc. exec header still allocated. 78 * ok: filled exec package, executable's vnode (unlocked). 79 * 80 * EXEC SWITCH ENTRY: 81 * Locked vnode to check, exec package, proc. 82 * 83 * EXEC SWITCH EXIT: 84 * ok: return 0, filled exec package, executable's vnode (unlocked). 85 * error: destructive: 86 * everything deallocated execept exec header. 87 * non-destructive: 88 * error code, executable's vnode (unlocked), 89 * exec header unmodified. 90 */ 91 int 92 check_exec(p, epp) 93 struct proc *p; 94 struct exec_package *epp; 95 { 96 int error, i; 97 struct vnode *vp; 98 struct nameidata *ndp; 99 size_t resid; 100 101 ndp = epp->ep_ndp; 102 ndp->ni_cnd.cn_nameiop = LOOKUP; 103 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 104 /* first get the vnode */ 105 if ((error = namei(ndp)) != 0) 106 return error; 107 epp->ep_vp = vp = ndp->ni_vp; 108 109 /* check access and type */ 110 if (vp->v_type != VREG) { 111 error = EACCES; 112 goto bad1; 113 } 114 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 115 goto bad1; 116 117 /* get attributes */ 118 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 119 goto bad1; 120 121 /* Check mount point */ 122 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 123 error = EACCES; 124 goto bad1; 125 } 126 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 127 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 128 129 /* try to open it */ 130 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 131 goto bad1; 132 133 /* unlock vp, since we need it unlocked from here on out. */ 134 VOP_UNLOCK(vp, 0); 135 136 /* now we have the file, get the exec header */ 137 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 138 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 139 if (error) 140 goto bad2; 141 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 142 143 /* 144 * set up the vmcmds for creation of the process 145 * address space 146 */ 147 error = ENOEXEC; 148 for (i = 0; i < nexecs && error != 0; i++) { 149 int newerror; 150 151 if (execsw[i].es_check == NULL) 152 continue; 153 154 newerror = (*execsw[i].es_check)(p, epp); 155 /* make sure the first "interesting" error code is saved. */ 156 if (!newerror || error == ENOEXEC) 157 error = newerror; 158 if (epp->ep_flags & EXEC_DESTR && error != 0) 159 return error; 160 } 161 if (!error) { 162 /* check that entry point is sane */ 163 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 164 error = ENOEXEC; 165 166 /* check limits */ 167 if ((epp->ep_tsize > MAXTSIZ) || 168 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 169 error = ENOMEM; 170 171 if (!error) 172 return (0); 173 } 174 175 /* 176 * free any vmspace-creation commands, 177 * and release their references 178 */ 179 kill_vmcmds(&epp->ep_vmcmds); 180 181 bad2: 182 /* 183 * close and release the vnode, restore the old one, free the 184 * pathname buf, and punt. 185 */ 186 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 187 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 188 vput(vp); 189 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 190 return error; 191 192 bad1: 193 /* 194 * free the namei pathname buffer, and put the vnode 195 * (which we don't yet have open). 196 */ 197 vput(vp); /* was still locked */ 198 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 199 return error; 200 } 201 202 /* 203 * exec system call 204 */ 205 /* ARGSUSED */ 206 int 207 sys_execve(p, v, retval) 208 struct proc *p; 209 void *v; 210 register_t *retval; 211 { 212 struct sys_execve_args /* { 213 syscallarg(const char *) path; 214 syscallarg(char * const *) argp; 215 syscallarg(char * const *) envp; 216 } */ *uap = v; 217 int error, i; 218 struct exec_package pack; 219 struct nameidata nid; 220 struct vattr attr; 221 struct ucred *cred = p->p_ucred; 222 char *argp; 223 char * const *cpp; 224 char *dp, *sp; 225 long argc, envc; 226 size_t len; 227 char *stack; 228 struct ps_strings arginfo; 229 struct vmspace *vm; 230 char **tmpfap; 231 int szsigcode; 232 extern struct emul emul_netbsd; 233 234 /* 235 * figure out the maximum size of an exec header, if necessary. 236 * XXX should be able to keep LKM code from modifying exec switch 237 * when we're still using it, but... 238 */ 239 if (exec_maxhdrsz == 0) { 240 for (i = 0; i < nexecs; i++) 241 if (execsw[i].es_check != NULL 242 && execsw[i].es_hdrsz > exec_maxhdrsz) 243 exec_maxhdrsz = execsw[i].es_hdrsz; 244 } 245 246 /* init the namei data to point the file user's program name */ 247 /* XXX cgd 960926: why do this here? most will be clobbered. */ 248 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 249 250 /* 251 * initialize the fields of the exec package. 252 */ 253 pack.ep_name = SCARG(uap, path); 254 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 255 pack.ep_hdrlen = exec_maxhdrsz; 256 pack.ep_hdrvalid = 0; 257 pack.ep_ndp = &nid; 258 pack.ep_emul_arg = NULL; 259 pack.ep_vmcmds.evs_cnt = 0; 260 pack.ep_vmcmds.evs_used = 0; 261 pack.ep_vap = &attr; 262 pack.ep_emul = &emul_netbsd; 263 pack.ep_flags = 0; 264 265 /* see if we can run it. */ 266 if ((error = check_exec(p, &pack)) != 0) 267 goto freehdr; 268 269 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 270 271 /* allocate an argument buffer */ 272 argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS); 273 #ifdef DIAGNOSTIC 274 if (argp == (vaddr_t) 0) 275 panic("execve: argp == NULL"); 276 #endif 277 dp = argp; 278 argc = 0; 279 280 /* copy the fake args list, if there's one, freeing it as we go */ 281 if (pack.ep_flags & EXEC_HASARGL) { 282 tmpfap = pack.ep_fa; 283 while (*tmpfap != NULL) { 284 char *cp; 285 286 cp = *tmpfap; 287 while (*cp) 288 *dp++ = *cp++; 289 dp++; 290 291 FREE(*tmpfap, M_EXEC); 292 tmpfap++; argc++; 293 } 294 FREE(pack.ep_fa, M_EXEC); 295 pack.ep_flags &= ~EXEC_HASARGL; 296 } 297 298 /* Now get argv & environment */ 299 if (!(cpp = SCARG(uap, argp))) { 300 error = EINVAL; 301 goto bad; 302 } 303 304 if (pack.ep_flags & EXEC_SKIPARG) 305 cpp++; 306 307 while (1) { 308 len = argp + ARG_MAX - dp; 309 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 310 goto bad; 311 if (!sp) 312 break; 313 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 314 if (error == ENAMETOOLONG) 315 error = E2BIG; 316 goto bad; 317 } 318 dp += len; 319 cpp++; 320 argc++; 321 } 322 323 envc = 0; 324 /* environment need not be there */ 325 if ((cpp = SCARG(uap, envp)) != NULL ) { 326 while (1) { 327 len = argp + ARG_MAX - dp; 328 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 329 goto bad; 330 if (!sp) 331 break; 332 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 333 if (error == ENAMETOOLONG) 334 error = E2BIG; 335 goto bad; 336 } 337 dp += len; 338 cpp++; 339 envc++; 340 } 341 } 342 343 dp = (char *) ALIGN(dp); 344 345 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 346 347 /* Now check if args & environ fit into new stack */ 348 if (pack.ep_flags & EXEC_32) 349 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(int) + 350 sizeof(int) + dp + STACKGAPLEN + szsigcode + 351 sizeof(struct ps_strings)) - argp; 352 else 353 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 354 sizeof(int) + dp + STACKGAPLEN + szsigcode + 355 sizeof(struct ps_strings)) - argp; 356 357 len = ALIGN(len); /* make the stack "safely" aligned */ 358 359 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 360 error = ENOMEM; 361 goto bad; 362 } 363 364 /* adjust "active stack depth" for process VSZ */ 365 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 366 367 /* 368 * Do whatever is necessary to prepare the address space 369 * for remapping. Note that this might replace the current 370 * vmspace with another! 371 */ 372 uvmspace_exec(p); 373 374 /* Now map address space */ 375 vm = p->p_vmspace; 376 vm->vm_taddr = (char *) pack.ep_taddr; 377 vm->vm_tsize = btoc(pack.ep_tsize); 378 vm->vm_daddr = (char *) pack.ep_daddr; 379 vm->vm_dsize = btoc(pack.ep_dsize); 380 vm->vm_ssize = btoc(pack.ep_ssize); 381 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 382 383 /* create the new process's VM space by running the vmcmds */ 384 #ifdef DIAGNOSTIC 385 if (pack.ep_vmcmds.evs_used == 0) 386 panic("execve: no vmcmds"); 387 #endif 388 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 389 struct exec_vmcmd *vcp; 390 391 vcp = &pack.ep_vmcmds.evs_cmds[i]; 392 error = (*vcp->ev_proc)(p, vcp); 393 } 394 395 /* free the vmspace-creation commands, and release their references */ 396 kill_vmcmds(&pack.ep_vmcmds); 397 398 /* if an error happened, deallocate and punt */ 399 if (error) 400 goto exec_abort; 401 402 /* remember information about the process */ 403 arginfo.ps_nargvstr = argc; 404 arginfo.ps_nenvstr = envc; 405 406 stack = (char *) (USRSTACK - len); 407 /* Now copy argc, args & environ to new stack */ 408 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 409 goto exec_abort; 410 411 /* copy out the process's ps_strings structure */ 412 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 413 goto exec_abort; 414 415 /* fill process ps_strings info */ 416 p->p_psstr = PS_STRINGS; 417 p->p_psargv = offsetof(struct ps_strings, ps_argvstr); 418 p->p_psnargv = offsetof(struct ps_strings, ps_nargvstr); 419 p->p_psenv = offsetof(struct ps_strings, ps_envstr); 420 p->p_psnenv = offsetof(struct ps_strings, ps_nenvstr); 421 422 /* copy out the process's signal trapoline code */ 423 if (szsigcode) { 424 if (copyout((char *)pack.ep_emul->e_sigcode, 425 p->p_sigacts->ps_sigcode = (char *)PS_STRINGS - szsigcode, 426 szsigcode)) 427 goto exec_abort; 428 #ifdef PMAP_NEED_PROCWR 429 /* This is code. Let the pmap do what is needed. */ 430 pmap_procwr(p, (vaddr_t)p->p_sigacts->ps_sigcode, szsigcode); 431 #endif 432 } 433 434 stopprofclock(p); /* stop profiling */ 435 fdcloseexec(p); /* handle close on exec */ 436 execsigs(p); /* reset catched signals */ 437 p->p_ctxlink = NULL; /* reset ucontext link */ 438 439 /* set command name & other accounting info */ 440 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 441 memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, len); 442 p->p_comm[len] = 0; 443 p->p_acflag &= ~AFORK; 444 445 /* record proc's vnode, for use by procfs and others */ 446 if (p->p_textvp) 447 vrele(p->p_textvp); 448 VREF(pack.ep_vp); 449 p->p_textvp = pack.ep_vp; 450 451 p->p_flag |= P_EXEC; 452 if (p->p_flag & P_PPWAIT) { 453 p->p_flag &= ~P_PPWAIT; 454 wakeup((caddr_t) p->p_pptr); 455 } 456 457 /* 458 * deal with set[ug]id. 459 * MNT_NOSUID and P_TRACED have already been used to disable s[ug]id. 460 */ 461 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 462 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 463 p->p_ucred = crcopy(cred); 464 #ifdef KTRACE 465 /* 466 * If process is being ktraced, turn off - unless 467 * root set it. 468 */ 469 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) 470 ktrderef(p); 471 #endif 472 if (attr.va_mode & S_ISUID) 473 p->p_ucred->cr_uid = attr.va_uid; 474 if (attr.va_mode & S_ISGID) 475 p->p_ucred->cr_gid = attr.va_gid; 476 p_sugid(p); 477 } else 478 p->p_flag &= ~P_SUGID; 479 p->p_cred->p_svuid = p->p_ucred->cr_uid; 480 p->p_cred->p_svgid = p->p_ucred->cr_gid; 481 482 doexechooks(p); 483 484 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 485 486 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 487 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 488 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 489 vput(pack.ep_vp); 490 491 /* setup new registers and do misc. setup. */ 492 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 493 494 if (p->p_flag & P_TRACED) 495 psignal(p, SIGTRAP); 496 497 p->p_emul = pack.ep_emul; 498 FREE(pack.ep_hdr, M_EXEC); 499 500 #ifdef KTRACE 501 if (KTRPOINT(p, KTR_EMUL)) 502 ktremul(p); 503 #endif 504 505 return (EJUSTRETURN); 506 507 bad: 508 /* free the vmspace-creation commands, and release their references */ 509 kill_vmcmds(&pack.ep_vmcmds); 510 /* kill any opened file descriptor, if necessary */ 511 if (pack.ep_flags & EXEC_HASFD) { 512 pack.ep_flags &= ~EXEC_HASFD; 513 (void) fdrelease(p, pack.ep_fd); 514 } 515 /* close and put the exec'd file */ 516 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 517 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 518 vput(pack.ep_vp); 519 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 520 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 521 522 freehdr: 523 FREE(pack.ep_hdr, M_EXEC); 524 return error; 525 526 exec_abort: 527 /* 528 * the old process doesn't exist anymore. exit gracefully. 529 * get rid of the (new) address space we have created, if any, get rid 530 * of our namei data and vnode, and exit noting failure 531 */ 532 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 533 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 534 if (pack.ep_emul_arg) 535 FREE(pack.ep_emul_arg, M_TEMP); 536 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 537 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 538 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 539 vput(pack.ep_vp); 540 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 541 FREE(pack.ep_hdr, M_EXEC); 542 exit1(p, W_EXITCODE(0, SIGABRT)); 543 exit1(p, -1); 544 545 /* NOTREACHED */ 546 return 0; 547 } 548 549 550 void * 551 copyargs(pack, arginfo, stack, argp) 552 struct exec_package *pack; 553 struct ps_strings *arginfo; 554 void *stack; 555 void *argp; 556 { 557 char **cpp = stack; 558 char *dp, *sp; 559 size_t len; 560 void *nullp = NULL; 561 int argc = arginfo->ps_nargvstr; 562 int envc = arginfo->ps_nenvstr; 563 564 if (copyout(&argc, cpp++, sizeof(argc))) 565 return NULL; 566 567 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 568 sp = argp; 569 570 /* XXX don't copy them out, remap them! */ 571 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 572 573 for (; --argc >= 0; sp += len, dp += len) 574 if (copyout(&dp, cpp++, sizeof(dp)) || 575 copyoutstr(sp, dp, ARG_MAX, &len)) 576 return NULL; 577 578 if (copyout(&nullp, cpp++, sizeof(nullp))) 579 return NULL; 580 581 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 582 583 for (; --envc >= 0; sp += len, dp += len) 584 if (copyout(&dp, cpp++, sizeof(dp)) || 585 copyoutstr(sp, dp, ARG_MAX, &len)) 586 return NULL; 587 588 if (copyout(&nullp, cpp++, sizeof(nullp))) 589 return NULL; 590 591 return cpp; 592 } 593