kern_exec.c revision 1.88
1 /* $NetBSD: kern_exec.c,v 1.88 1998/02/05 07:59:48 mrg 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 <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/filedesc.h> 38 #include <sys/kernel.h> 39 #include <sys/proc.h> 40 #include <sys/mount.h> 41 #include <sys/malloc.h> 42 #include <sys/namei.h> 43 #include <sys/vnode.h> 44 #include <sys/file.h> 45 #include <sys/acct.h> 46 #include <sys/exec.h> 47 #include <sys/ktrace.h> 48 #include <sys/resourcevar.h> 49 #include <sys/wait.h> 50 #include <sys/mman.h> 51 #include <sys/signalvar.h> 52 #include <sys/stat.h> 53 54 #include <sys/syscallargs.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_kern.h> 58 59 #if defined(UVM) 60 #include <uvm/uvm_extern.h> 61 #endif 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 int 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 don't need it locked from here on out. */ 134 VOP_UNLOCK(vp); 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 * unlock and close the vnode, restore the old one, free the 184 * pathname buf, and punt. 185 */ 186 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 187 vrele(vp); 188 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 189 return error; 190 191 bad1: 192 /* 193 * free the namei pathname buffer, and put the vnode 194 * (which we don't yet have open). 195 */ 196 vput(vp); /* was still locked */ 197 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 198 return error; 199 } 200 201 /* 202 * exec system call 203 */ 204 /* ARGSUSED */ 205 int 206 sys_execve(p, v, retval) 207 register struct proc *p; 208 void *v; 209 register_t *retval; 210 { 211 register struct sys_execve_args /* { 212 syscallarg(const char *) path; 213 syscallarg(char * const *) argp; 214 syscallarg(char * const *) envp; 215 } */ *uap = v; 216 int error, i; 217 struct exec_package pack; 218 struct nameidata nid; 219 struct vattr attr; 220 struct ucred *cred = p->p_ucred; 221 char *argp; 222 char * const *cpp; 223 char *dp, *sp; 224 long argc, envc; 225 size_t len; 226 char *stack; 227 struct ps_strings arginfo; 228 struct vmspace *vm; 229 char **tmpfap; 230 int szsigcode; 231 extern struct emul emul_netbsd; 232 233 /* 234 * figure out the maximum size of an exec header, if necessary. 235 * XXX should be able to keep LKM code from modifying exec switch 236 * when we're still using it, but... 237 */ 238 if (exec_maxhdrsz == 0) { 239 for (i = 0; i < nexecs; i++) 240 if (execsw[i].es_check != NULL 241 && execsw[i].es_hdrsz > exec_maxhdrsz) 242 exec_maxhdrsz = execsw[i].es_hdrsz; 243 } 244 245 /* init the namei data to point the file user's program name */ 246 /* XXX cgd 960926: why do this here? most will be clobbered. */ 247 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 248 249 /* 250 * initialize the fields of the exec package. 251 */ 252 pack.ep_name = SCARG(uap, path); 253 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 254 pack.ep_hdrlen = exec_maxhdrsz; 255 pack.ep_hdrvalid = 0; 256 pack.ep_ndp = &nid; 257 pack.ep_emul_arg = NULL; 258 pack.ep_vmcmds.evs_cnt = 0; 259 pack.ep_vmcmds.evs_used = 0; 260 pack.ep_vap = &attr; 261 pack.ep_emul = &emul_netbsd; 262 pack.ep_flags = 0; 263 264 /* see if we can run it. */ 265 if ((error = check_exec(p, &pack)) != 0) 266 goto freehdr; 267 268 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 269 270 /* allocate an argument buffer */ 271 #if defined(UVM) 272 argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS); 273 #else 274 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 275 #endif 276 #ifdef DIAGNOSTIC 277 if (argp == (vm_offset_t) 0) 278 panic("execve: argp == NULL"); 279 #endif 280 dp = argp; 281 argc = 0; 282 283 /* copy the fake args list, if there's one, freeing it as we go */ 284 if (pack.ep_flags & EXEC_HASARGL) { 285 tmpfap = pack.ep_fa; 286 while (*tmpfap != NULL) { 287 char *cp; 288 289 cp = *tmpfap; 290 while (*cp) 291 *dp++ = *cp++; 292 dp++; 293 294 FREE(*tmpfap, M_EXEC); 295 tmpfap++; argc++; 296 } 297 FREE(pack.ep_fa, M_EXEC); 298 pack.ep_flags &= ~EXEC_HASARGL; 299 } 300 301 /* Now get argv & environment */ 302 if (!(cpp = SCARG(uap, argp))) { 303 error = EINVAL; 304 goto bad; 305 } 306 307 if (pack.ep_flags & EXEC_SKIPARG) 308 cpp++; 309 310 while (1) { 311 len = argp + ARG_MAX - dp; 312 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 313 goto bad; 314 if (!sp) 315 break; 316 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 317 if (error == ENAMETOOLONG) 318 error = E2BIG; 319 goto bad; 320 } 321 dp += len; 322 cpp++; 323 argc++; 324 } 325 326 envc = 0; 327 /* environment need not be there */ 328 if ((cpp = SCARG(uap, envp)) != NULL ) { 329 while (1) { 330 len = argp + ARG_MAX - dp; 331 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 332 goto bad; 333 if (!sp) 334 break; 335 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 336 if (error == ENAMETOOLONG) 337 error = E2BIG; 338 goto bad; 339 } 340 dp += len; 341 cpp++; 342 envc++; 343 } 344 } 345 346 dp = (char *) ALIGN(dp); 347 348 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 349 350 /* Now check if args & environ fit into new stack */ 351 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 352 sizeof(long) + dp + STACKGAPLEN + szsigcode + 353 sizeof(struct ps_strings)) - argp; 354 355 len = ALIGN(len); /* make the stack "safely" aligned */ 356 357 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 358 error = ENOMEM; 359 goto bad; 360 } 361 362 /* adjust "active stack depth" for process VSZ */ 363 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 364 365 /* 366 * Do whatever is necessary to prepare the address space 367 * for remapping. Note that this might replace the current 368 * vmspace with another! 369 */ 370 #if defined(UVM) 371 uvmspace_exec(p); 372 #else 373 vmspace_exec(p); 374 #endif 375 376 /* Now map address space */ 377 vm = p->p_vmspace; 378 vm->vm_taddr = (char *) pack.ep_taddr; 379 vm->vm_tsize = btoc(pack.ep_tsize); 380 vm->vm_daddr = (char *) pack.ep_daddr; 381 vm->vm_dsize = btoc(pack.ep_dsize); 382 vm->vm_ssize = btoc(pack.ep_ssize); 383 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 384 385 /* create the new process's VM space by running the vmcmds */ 386 #ifdef DIAGNOSTIC 387 if (pack.ep_vmcmds.evs_used == 0) 388 panic("execve: no vmcmds"); 389 #endif 390 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 391 struct exec_vmcmd *vcp; 392 393 vcp = &pack.ep_vmcmds.evs_cmds[i]; 394 error = (*vcp->ev_proc)(p, vcp); 395 } 396 397 /* free the vmspace-creation commands, and release their references */ 398 kill_vmcmds(&pack.ep_vmcmds); 399 400 /* if an error happened, deallocate and punt */ 401 if (error) 402 goto exec_abort; 403 404 /* remember information about the process */ 405 arginfo.ps_nargvstr = argc; 406 arginfo.ps_nenvstr = envc; 407 408 stack = (char *) (USRSTACK - len); 409 /* Now copy argc, args & environ to new stack */ 410 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 411 goto exec_abort; 412 413 /* copy out the process's ps_strings structure */ 414 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 415 goto exec_abort; 416 417 /* copy out the process's signal trapoline code */ 418 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 419 ((char *) PS_STRINGS) - szsigcode, 420 szsigcode)) 421 goto exec_abort; 422 423 fdcloseexec(p); /* handle close on exec */ 424 execsigs(p); /* reset catched signals */ 425 426 /* set command name & other accounting info */ 427 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 428 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 429 p->p_comm[len] = 0; 430 p->p_acflag &= ~AFORK; 431 432 /* record proc's vnode, for use by procfs and others */ 433 if (p->p_textvp) 434 vrele(p->p_textvp); 435 VREF(pack.ep_vp); 436 p->p_textvp = pack.ep_vp; 437 438 p->p_flag |= P_EXEC; 439 if (p->p_flag & P_PPWAIT) { 440 p->p_flag &= ~P_PPWAIT; 441 wakeup((caddr_t) p->p_pptr); 442 } 443 444 /* 445 * deal with set[ug]id. 446 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 447 */ 448 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 449 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 450 p->p_ucred = crcopy(cred); 451 #ifdef KTRACE 452 /* 453 * If process is being ktraced, turn off - unless 454 * root set it. 455 */ 456 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 457 vrele(p->p_tracep); 458 p->p_tracep = NULL; 459 p->p_traceflag = 0; 460 } 461 #endif 462 if (attr.va_mode & S_ISUID) 463 p->p_ucred->cr_uid = attr.va_uid; 464 if (attr.va_mode & S_ISGID) 465 p->p_ucred->cr_gid = attr.va_gid; 466 p->p_flag |= P_SUGID; 467 } else 468 p->p_flag &= ~P_SUGID; 469 p->p_cred->p_svuid = p->p_ucred->cr_uid; 470 p->p_cred->p_svgid = p->p_ucred->cr_gid; 471 472 #if defined(UVM) 473 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 474 #else 475 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 476 #endif 477 478 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 479 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 480 vrele(pack.ep_vp); 481 482 /* setup new registers and do misc. setup. */ 483 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 484 485 if (p->p_flag & P_TRACED) 486 psignal(p, SIGTRAP); 487 488 p->p_emul = pack.ep_emul; 489 FREE(pack.ep_hdr, M_EXEC); 490 491 #ifdef KTRACE 492 if (KTRPOINT(p, KTR_EMUL)) 493 ktremul(p->p_tracep, p->p_emul->e_name); 494 #endif 495 496 return (EJUSTRETURN); 497 498 bad: 499 /* free the vmspace-creation commands, and release their references */ 500 kill_vmcmds(&pack.ep_vmcmds); 501 /* kill any opened file descriptor, if necessary */ 502 if (pack.ep_flags & EXEC_HASFD) { 503 pack.ep_flags &= ~EXEC_HASFD; 504 (void) fdrelease(p, pack.ep_fd); 505 } 506 /* close and put the exec'd file */ 507 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 508 vrele(pack.ep_vp); 509 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 510 #if defined(UVM) 511 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 512 #else 513 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 514 #endif 515 516 freehdr: 517 FREE(pack.ep_hdr, M_EXEC); 518 return error; 519 520 exec_abort: 521 /* 522 * the old process doesn't exist anymore. exit gracefully. 523 * get rid of the (new) address space we have created, if any, get rid 524 * of our namei data and vnode, and exit noting failure 525 */ 526 #if defined(UVM) 527 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 528 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 529 #else 530 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 531 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 532 #endif 533 if (pack.ep_emul_arg) 534 FREE(pack.ep_emul_arg, M_TEMP); 535 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 536 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 537 vrele(pack.ep_vp); 538 #if defined(UVM) 539 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 540 #else 541 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 542 #endif 543 FREE(pack.ep_hdr, M_EXEC); 544 exit1(p, W_EXITCODE(0, SIGABRT)); 545 exit1(p, -1); 546 547 /* NOTREACHED */ 548 return 0; 549 } 550 551 552 void * 553 copyargs(pack, arginfo, stack, argp) 554 struct exec_package *pack; 555 struct ps_strings *arginfo; 556 void *stack; 557 void *argp; 558 { 559 char **cpp = stack; 560 char *dp, *sp; 561 size_t len; 562 void *nullp = NULL; 563 int argc = arginfo->ps_nargvstr; 564 int envc = arginfo->ps_nenvstr; 565 566 if (copyout(&argc, cpp++, sizeof(argc))) 567 return NULL; 568 569 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 570 sp = argp; 571 572 /* XXX don't copy them out, remap them! */ 573 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 574 575 for (; --argc >= 0; sp += len, dp += len) 576 if (copyout(&dp, cpp++, sizeof(dp)) || 577 copyoutstr(sp, dp, ARG_MAX, &len)) 578 return NULL; 579 580 if (copyout(&nullp, cpp++, sizeof(nullp))) 581 return NULL; 582 583 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 584 585 for (; --envc >= 0; sp += len, dp += len) 586 if (copyout(&dp, cpp++, sizeof(dp)) || 587 copyoutstr(sp, dp, ARG_MAX, &len)) 588 return NULL; 589 590 if (copyout(&nullp, cpp++, sizeof(nullp))) 591 return NULL; 592 593 return cpp; 594 } 595
Indexes created Thu Sep 25 02:09:54 GMT 2025