kern_exec.c revision 1.99
1 /* $NetBSD: kern_exec.c,v 1.99 1999/02/26 23:38:55 wrstuden 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 #include "opt_uvm.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/filedesc.h> 41 #include <sys/kernel.h> 42 #include <sys/proc.h> 43 #include <sys/mount.h> 44 #include <sys/malloc.h> 45 #include <sys/namei.h> 46 #include <sys/vnode.h> 47 #include <sys/file.h> 48 #include <sys/acct.h> 49 #include <sys/exec.h> 50 #include <sys/ktrace.h> 51 #include <sys/resourcevar.h> 52 #include <sys/wait.h> 53 #include <sys/mman.h> 54 #include <sys/signalvar.h> 55 #include <sys/stat.h> 56 57 #include <sys/syscallargs.h> 58 59 #include <vm/vm.h> 60 #include <vm/vm_kern.h> 61 62 #if defined(UVM) 63 #include <uvm/uvm_extern.h> 64 #endif 65 66 #include <machine/cpu.h> 67 #include <machine/reg.h> 68 69 /* 70 * check exec: 71 * given an "executable" described in the exec package's namei info, 72 * see what we can do with it. 73 * 74 * ON ENTRY: 75 * exec package with appropriate namei info 76 * proc pointer of exec'ing proc 77 * NO SELF-LOCKED VNODES 78 * 79 * ON EXIT: 80 * error: nothing held, etc. exec header still allocated. 81 * ok: filled exec package, executable's vnode (unlocked). 82 * 83 * EXEC SWITCH ENTRY: 84 * Locked vnode to check, exec package, proc. 85 * 86 * EXEC SWITCH EXIT: 87 * ok: return 0, filled exec package, executable's vnode (unlocked). 88 * error: destructive: 89 * everything deallocated execept exec header. 90 * non-destructive: 91 * error code, executable's vnode (unlocked), 92 * exec header unmodified. 93 */ 94 int 95 check_exec(p, epp) 96 struct proc *p; 97 struct exec_package *epp; 98 { 99 int error, i; 100 struct vnode *vp; 101 struct nameidata *ndp; 102 size_t resid; 103 104 ndp = epp->ep_ndp; 105 ndp->ni_cnd.cn_nameiop = LOOKUP; 106 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 107 /* first get the vnode */ 108 if ((error = namei(ndp)) != 0) 109 return error; 110 epp->ep_vp = vp = ndp->ni_vp; 111 112 /* check access and type */ 113 if (vp->v_type != VREG) { 114 error = EACCES; 115 goto bad1; 116 } 117 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 118 goto bad1; 119 120 /* get attributes */ 121 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 122 goto bad1; 123 124 /* Check mount point */ 125 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 126 error = EACCES; 127 goto bad1; 128 } 129 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 130 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 131 132 /* try to open it */ 133 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 134 goto bad1; 135 136 /* unlock vp, since we need it unlocked from here on out. */ 137 VOP_UNLOCK(vp, 0); 138 139 /* now we have the file, get the exec header */ 140 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 141 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 142 if (error) 143 goto bad2; 144 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 145 146 /* 147 * set up the vmcmds for creation of the process 148 * address space 149 */ 150 error = ENOEXEC; 151 for (i = 0; i < nexecs && error != 0; i++) { 152 int newerror; 153 154 if (execsw[i].es_check == NULL) 155 continue; 156 157 newerror = (*execsw[i].es_check)(p, epp); 158 /* make sure the first "interesting" error code is saved. */ 159 if (!newerror || error == ENOEXEC) 160 error = newerror; 161 if (epp->ep_flags & EXEC_DESTR && error != 0) 162 return error; 163 } 164 if (!error) { 165 /* check that entry point is sane */ 166 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 167 error = ENOEXEC; 168 169 /* check limits */ 170 if ((epp->ep_tsize > MAXTSIZ) || 171 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 172 error = ENOMEM; 173 174 if (!error) 175 return (0); 176 } 177 178 /* 179 * free any vmspace-creation commands, 180 * and release their references 181 */ 182 kill_vmcmds(&epp->ep_vmcmds); 183 184 bad2: 185 /* 186 * close and release the vnode, restore the old one, free the 187 * pathname buf, and punt. 188 */ 189 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 190 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 191 vput(vp); 192 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 193 return error; 194 195 bad1: 196 /* 197 * free the namei pathname buffer, and put the vnode 198 * (which we don't yet have open). 199 */ 200 vput(vp); /* was still locked */ 201 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 202 return error; 203 } 204 205 /* 206 * exec system call 207 */ 208 /* ARGSUSED */ 209 int 210 sys_execve(p, v, retval) 211 register struct proc *p; 212 void *v; 213 register_t *retval; 214 { 215 register struct sys_execve_args /* { 216 syscallarg(const char *) path; 217 syscallarg(char * const *) argp; 218 syscallarg(char * const *) envp; 219 } */ *uap = v; 220 int error, i; 221 struct exec_package pack; 222 struct nameidata nid; 223 struct vattr attr; 224 struct ucred *cred = p->p_ucred; 225 char *argp; 226 char * const *cpp; 227 char *dp, *sp; 228 long argc, envc; 229 size_t len; 230 char *stack; 231 struct ps_strings arginfo; 232 struct vmspace *vm; 233 char **tmpfap; 234 int szsigcode; 235 extern struct emul emul_netbsd; 236 237 /* 238 * figure out the maximum size of an exec header, if necessary. 239 * XXX should be able to keep LKM code from modifying exec switch 240 * when we're still using it, but... 241 */ 242 if (exec_maxhdrsz == 0) { 243 for (i = 0; i < nexecs; i++) 244 if (execsw[i].es_check != NULL 245 && execsw[i].es_hdrsz > exec_maxhdrsz) 246 exec_maxhdrsz = execsw[i].es_hdrsz; 247 } 248 249 /* init the namei data to point the file user's program name */ 250 /* XXX cgd 960926: why do this here? most will be clobbered. */ 251 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 252 253 /* 254 * initialize the fields of the exec package. 255 */ 256 pack.ep_name = SCARG(uap, path); 257 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 258 pack.ep_hdrlen = exec_maxhdrsz; 259 pack.ep_hdrvalid = 0; 260 pack.ep_ndp = &nid; 261 pack.ep_emul_arg = NULL; 262 pack.ep_vmcmds.evs_cnt = 0; 263 pack.ep_vmcmds.evs_used = 0; 264 pack.ep_vap = &attr; 265 pack.ep_emul = &emul_netbsd; 266 pack.ep_flags = 0; 267 268 /* see if we can run it. */ 269 if ((error = check_exec(p, &pack)) != 0) 270 goto freehdr; 271 272 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 273 274 /* allocate an argument buffer */ 275 #if defined(UVM) 276 argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS); 277 #else 278 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 279 #endif 280 #ifdef DIAGNOSTIC 281 if (argp == (vaddr_t) 0) 282 panic("execve: argp == NULL"); 283 #endif 284 dp = argp; 285 argc = 0; 286 287 /* copy the fake args list, if there's one, freeing it as we go */ 288 if (pack.ep_flags & EXEC_HASARGL) { 289 tmpfap = pack.ep_fa; 290 while (*tmpfap != NULL) { 291 char *cp; 292 293 cp = *tmpfap; 294 while (*cp) 295 *dp++ = *cp++; 296 dp++; 297 298 FREE(*tmpfap, M_EXEC); 299 tmpfap++; argc++; 300 } 301 FREE(pack.ep_fa, M_EXEC); 302 pack.ep_flags &= ~EXEC_HASARGL; 303 } 304 305 /* Now get argv & environment */ 306 if (!(cpp = SCARG(uap, argp))) { 307 error = EINVAL; 308 goto bad; 309 } 310 311 if (pack.ep_flags & EXEC_SKIPARG) 312 cpp++; 313 314 while (1) { 315 len = argp + ARG_MAX - dp; 316 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 317 goto bad; 318 if (!sp) 319 break; 320 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 321 if (error == ENAMETOOLONG) 322 error = E2BIG; 323 goto bad; 324 } 325 dp += len; 326 cpp++; 327 argc++; 328 } 329 330 envc = 0; 331 /* environment need not be there */ 332 if ((cpp = SCARG(uap, envp)) != NULL ) { 333 while (1) { 334 len = argp + ARG_MAX - dp; 335 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 336 goto bad; 337 if (!sp) 338 break; 339 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 340 if (error == ENAMETOOLONG) 341 error = E2BIG; 342 goto bad; 343 } 344 dp += len; 345 cpp++; 346 envc++; 347 } 348 } 349 350 dp = (char *) ALIGN(dp); 351 352 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 353 354 /* Now check if args & environ fit into new stack */ 355 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 356 sizeof(long) + dp + STACKGAPLEN + szsigcode + 357 sizeof(struct ps_strings)) - argp; 358 359 len = ALIGN(len); /* make the stack "safely" aligned */ 360 361 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 362 error = ENOMEM; 363 goto bad; 364 } 365 366 /* adjust "active stack depth" for process VSZ */ 367 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 368 369 /* 370 * Do whatever is necessary to prepare the address space 371 * for remapping. Note that this might replace the current 372 * vmspace with another! 373 */ 374 #if defined(UVM) 375 uvmspace_exec(p); 376 #else 377 vmspace_exec(p); 378 #endif 379 380 /* Now map address space */ 381 vm = p->p_vmspace; 382 vm->vm_taddr = (char *) pack.ep_taddr; 383 vm->vm_tsize = btoc(pack.ep_tsize); 384 vm->vm_daddr = (char *) pack.ep_daddr; 385 vm->vm_dsize = btoc(pack.ep_dsize); 386 vm->vm_ssize = btoc(pack.ep_ssize); 387 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 388 389 /* create the new process's VM space by running the vmcmds */ 390 #ifdef DIAGNOSTIC 391 if (pack.ep_vmcmds.evs_used == 0) 392 panic("execve: no vmcmds"); 393 #endif 394 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 395 struct exec_vmcmd *vcp; 396 397 vcp = &pack.ep_vmcmds.evs_cmds[i]; 398 error = (*vcp->ev_proc)(p, vcp); 399 } 400 401 /* free the vmspace-creation commands, and release their references */ 402 kill_vmcmds(&pack.ep_vmcmds); 403 404 /* if an error happened, deallocate and punt */ 405 if (error) 406 goto exec_abort; 407 408 /* remember information about the process */ 409 arginfo.ps_nargvstr = argc; 410 arginfo.ps_nenvstr = envc; 411 412 stack = (char *) (USRSTACK - len); 413 /* Now copy argc, args & environ to new stack */ 414 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 415 goto exec_abort; 416 417 /* copy out the process's ps_strings structure */ 418 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 419 goto exec_abort; 420 421 /* copy out the process's signal trapoline code */ 422 if (szsigcode) { 423 if (copyout((char *)pack.ep_emul->e_sigcode, 424 p->p_sigacts->ps_sigcode = (char *)PS_STRINGS - szsigcode, 425 szsigcode)) 426 goto exec_abort; 427 } 428 429 fdcloseexec(p); /* handle close on exec */ 430 execsigs(p); /* reset catched signals */ 431 p->p_ctxlink = NULL; /* reset ucontext link */ 432 433 /* set command name & other accounting info */ 434 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 435 memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, len); 436 p->p_comm[len] = 0; 437 p->p_acflag &= ~AFORK; 438 439 /* record proc's vnode, for use by procfs and others */ 440 if (p->p_textvp) 441 vrele(p->p_textvp); 442 VREF(pack.ep_vp); 443 p->p_textvp = pack.ep_vp; 444 445 p->p_flag |= P_EXEC; 446 if (p->p_flag & P_PPWAIT) { 447 p->p_flag &= ~P_PPWAIT; 448 wakeup((caddr_t) p->p_pptr); 449 } 450 451 /* 452 * deal with set[ug]id. 453 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 454 */ 455 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 456 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 457 p->p_ucred = crcopy(cred); 458 #ifdef KTRACE 459 /* 460 * If process is being ktraced, turn off - unless 461 * root set it. 462 */ 463 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) 464 ktrderef(p); 465 #endif 466 if (attr.va_mode & S_ISUID) 467 p->p_ucred->cr_uid = attr.va_uid; 468 if (attr.va_mode & S_ISGID) 469 p->p_ucred->cr_gid = attr.va_gid; 470 p->p_flag |= P_SUGID; 471 } else 472 p->p_flag &= ~P_SUGID; 473 p->p_cred->p_svuid = p->p_ucred->cr_uid; 474 p->p_cred->p_svgid = p->p_ucred->cr_gid; 475 476 #if defined(UVM) 477 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 478 #else 479 kmem_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 480 #endif 481 482 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 483 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 484 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 485 vput(pack.ep_vp); 486 487 /* setup new registers and do misc. setup. */ 488 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 489 490 if (p->p_flag & P_TRACED) 491 psignal(p, SIGTRAP); 492 493 p->p_emul = pack.ep_emul; 494 FREE(pack.ep_hdr, M_EXEC); 495 496 #ifdef KTRACE 497 if (KTRPOINT(p, KTR_EMUL)) 498 ktremul(p->p_tracep, p, p->p_emul->e_name); 499 #endif 500 501 return (EJUSTRETURN); 502 503 bad: 504 /* free the vmspace-creation commands, and release their references */ 505 kill_vmcmds(&pack.ep_vmcmds); 506 /* kill any opened file descriptor, if necessary */ 507 if (pack.ep_flags & EXEC_HASFD) { 508 pack.ep_flags &= ~EXEC_HASFD; 509 (void) fdrelease(p, pack.ep_fd); 510 } 511 /* close and put the exec'd file */ 512 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 513 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 514 vput(pack.ep_vp); 515 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 516 #if defined(UVM) 517 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 518 #else 519 kmem_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 520 #endif 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 #if defined(UVM) 533 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 534 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 535 #else 536 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 537 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 538 #endif 539 if (pack.ep_emul_arg) 540 FREE(pack.ep_emul_arg, M_TEMP); 541 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 542 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 543 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 544 vput(pack.ep_vp); 545 #if defined(UVM) 546 uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 547 #else 548 kmem_free_wakeup(exec_map, (vaddr_t) argp, NCARGS); 549 #endif 550 FREE(pack.ep_hdr, M_EXEC); 551 exit1(p, W_EXITCODE(0, SIGABRT)); 552 exit1(p, -1); 553 554 /* NOTREACHED */ 555 return 0; 556 } 557 558 559 void * 560 copyargs(pack, arginfo, stack, argp) 561 struct exec_package *pack; 562 struct ps_strings *arginfo; 563 void *stack; 564 void *argp; 565 { 566 char **cpp = stack; 567 char *dp, *sp; 568 size_t len; 569 void *nullp = NULL; 570 int argc = arginfo->ps_nargvstr; 571 int envc = arginfo->ps_nenvstr; 572 573 if (copyout(&argc, cpp++, sizeof(argc))) 574 return NULL; 575 576 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 577 sp = argp; 578 579 /* XXX don't copy them out, remap them! */ 580 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 581 582 for (; --argc >= 0; sp += len, dp += len) 583 if (copyout(&dp, cpp++, sizeof(dp)) || 584 copyoutstr(sp, dp, ARG_MAX, &len)) 585 return NULL; 586 587 if (copyout(&nullp, cpp++, sizeof(nullp))) 588 return NULL; 589 590 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 591 592 for (; --envc >= 0; sp += len, dp += len) 593 if (copyout(&dp, cpp++, sizeof(dp)) || 594 copyoutstr(sp, dp, ARG_MAX, &len)) 595 return NULL; 596 597 if (copyout(&nullp, cpp++, sizeof(nullp))) 598 return NULL; 599 600 return cpp; 601 } 602
Indexes created Mon Sep 22 21:09:42 GMT 2025