kern_exec.c revision 1.95
1 /* $NetBSD: kern_exec.c,v 1.95 1998/08/13 02:10:57 eeh 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 don't need it locked 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 * unlock and close the vnode, restore the old one, free the 187 * pathname buf, and punt. 188 */ 189 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 190 vrele(vp); 191 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 192 return error; 193 194 bad1: 195 /* 196 * free the namei pathname buffer, and put the vnode 197 * (which we don't yet have open). 198 */ 199 vput(vp); /* was still locked */ 200 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 201 return error; 202 } 203 204 /* 205 * exec system call 206 */ 207 /* ARGSUSED */ 208 int 209 sys_execve(p, v, retval) 210 register struct proc *p; 211 void *v; 212 register_t *retval; 213 { 214 register struct sys_execve_args /* { 215 syscallarg(const char *) path; 216 syscallarg(char * const *) argp; 217 syscallarg(char * const *) envp; 218 } */ *uap = v; 219 int error, i; 220 struct exec_package pack; 221 struct nameidata nid; 222 struct vattr attr; 223 struct ucred *cred = p->p_ucred; 224 char *argp; 225 char * const *cpp; 226 char *dp, *sp; 227 long argc, envc; 228 size_t len; 229 char *stack; 230 struct ps_strings arginfo; 231 struct vmspace *vm; 232 char **tmpfap; 233 int szsigcode; 234 extern struct emul emul_netbsd; 235 236 /* 237 * figure out the maximum size of an exec header, if necessary. 238 * XXX should be able to keep LKM code from modifying exec switch 239 * when we're still using it, but... 240 */ 241 if (exec_maxhdrsz == 0) { 242 for (i = 0; i < nexecs; i++) 243 if (execsw[i].es_check != NULL 244 && execsw[i].es_hdrsz > exec_maxhdrsz) 245 exec_maxhdrsz = execsw[i].es_hdrsz; 246 } 247 248 /* init the namei data to point the file user's program name */ 249 /* XXX cgd 960926: why do this here? most will be clobbered. */ 250 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 251 252 /* 253 * initialize the fields of the exec package. 254 */ 255 pack.ep_name = SCARG(uap, path); 256 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 257 pack.ep_hdrlen = exec_maxhdrsz; 258 pack.ep_hdrvalid = 0; 259 pack.ep_ndp = &nid; 260 pack.ep_emul_arg = NULL; 261 pack.ep_vmcmds.evs_cnt = 0; 262 pack.ep_vmcmds.evs_used = 0; 263 pack.ep_vap = &attr; 264 pack.ep_emul = &emul_netbsd; 265 pack.ep_flags = 0; 266 267 /* see if we can run it. */ 268 if ((error = check_exec(p, &pack)) != 0) 269 goto freehdr; 270 271 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 272 273 /* allocate an argument buffer */ 274 #if defined(UVM) 275 argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS); 276 #else 277 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 278 #endif 279 #ifdef DIAGNOSTIC 280 if (argp == (vaddr_t) 0) 281 panic("execve: argp == NULL"); 282 #endif 283 dp = argp; 284 argc = 0; 285 286 /* copy the fake args list, if there's one, freeing it as we go */ 287 if (pack.ep_flags & EXEC_HASARGL) { 288 tmpfap = pack.ep_fa; 289 while (*tmpfap != NULL) { 290 char *cp; 291 292 cp = *tmpfap; 293 while (*cp) 294 *dp++ = *cp++; 295 dp++; 296 297 FREE(*tmpfap, M_EXEC); 298 tmpfap++; argc++; 299 } 300 FREE(pack.ep_fa, M_EXEC); 301 pack.ep_flags &= ~EXEC_HASARGL; 302 } 303 304 /* Now get argv & environment */ 305 if (!(cpp = SCARG(uap, argp))) { 306 error = EINVAL; 307 goto bad; 308 } 309 310 if (pack.ep_flags & EXEC_SKIPARG) 311 cpp++; 312 313 while (1) { 314 len = argp + ARG_MAX - dp; 315 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 316 goto bad; 317 if (!sp) 318 break; 319 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 320 if (error == ENAMETOOLONG) 321 error = E2BIG; 322 goto bad; 323 } 324 dp += len; 325 cpp++; 326 argc++; 327 } 328 329 envc = 0; 330 /* environment need not be there */ 331 if ((cpp = SCARG(uap, envp)) != NULL ) { 332 while (1) { 333 len = argp + ARG_MAX - dp; 334 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 335 goto bad; 336 if (!sp) 337 break; 338 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 339 if (error == ENAMETOOLONG) 340 error = E2BIG; 341 goto bad; 342 } 343 dp += len; 344 cpp++; 345 envc++; 346 } 347 } 348 349 dp = (char *) ALIGN(dp); 350 351 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 352 353 /* Now check if args & environ fit into new stack */ 354 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 355 sizeof(long) + dp + STACKGAPLEN + szsigcode + 356 sizeof(struct ps_strings)) - argp; 357 358 len = ALIGN(len); /* make the stack "safely" aligned */ 359 360 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 361 error = ENOMEM; 362 goto bad; 363 } 364 365 /* adjust "active stack depth" for process VSZ */ 366 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 367 368 /* 369 * Do whatever is necessary to prepare the address space 370 * for remapping. Note that this might replace the current 371 * vmspace with another! 372 */ 373 #if defined(UVM) 374 uvmspace_exec(p); 375 #else 376 vmspace_exec(p); 377 #endif 378 379 /* Now map address space */ 380 vm = p->p_vmspace; 381 vm->vm_taddr = (char *) pack.ep_taddr; 382 vm->vm_tsize = btoc(pack.ep_tsize); 383 vm->vm_daddr = (char *) pack.ep_daddr; 384 vm->vm_dsize = btoc(pack.ep_dsize); 385 vm->vm_ssize = btoc(pack.ep_ssize); 386 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 387 388 /* create the new process's VM space by running the vmcmds */ 389 #ifdef DIAGNOSTIC 390 if (pack.ep_vmcmds.evs_used == 0) 391 panic("execve: no vmcmds"); 392 #endif 393 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 394 struct exec_vmcmd *vcp; 395 396 vcp = &pack.ep_vmcmds.evs_cmds[i]; 397 error = (*vcp->ev_proc)(p, vcp); 398 } 399 400 /* free the vmspace-creation commands, and release their references */ 401 kill_vmcmds(&pack.ep_vmcmds); 402 403 /* if an error happened, deallocate and punt */ 404 if (error) 405 goto exec_abort; 406 407 /* remember information about the process */ 408 arginfo.ps_nargvstr = argc; 409 arginfo.ps_nenvstr = envc; 410 411 stack = (char *) (USRSTACK - len); 412 /* Now copy argc, args & environ to new stack */ 413 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 414 goto exec_abort; 415 416 /* copy out the process's ps_strings structure */ 417 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 418 goto exec_abort; 419 420 /* copy out the process's signal trapoline code */ 421 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 422 ((char *) PS_STRINGS) - szsigcode, 423 szsigcode)) 424 goto exec_abort; 425 426 fdcloseexec(p); /* handle close on exec */ 427 execsigs(p); /* reset catched signals */ 428 429 /* set command name & other accounting info */ 430 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 431 memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, len); 432 p->p_comm[len] = 0; 433 p->p_acflag &= ~AFORK; 434 435 /* record proc's vnode, for use by procfs and others */ 436 if (p->p_textvp) 437 vrele(p->p_textvp); 438 VREF(pack.ep_vp); 439 p->p_textvp = pack.ep_vp; 440 441 p->p_flag |= P_EXEC; 442 if (p->p_flag & P_PPWAIT) { 443 p->p_flag &= ~P_PPWAIT; 444 wakeup((caddr_t) p->p_pptr); 445 } 446 447 /* 448 * deal with set[ug]id. 449 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 450 */ 451 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 452 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 453 p->p_ucred = crcopy(cred); 454 #ifdef KTRACE 455 /* 456 * If process is being ktraced, turn off - unless 457 * root set it. 458 */ 459 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) 460 ktrderef(p); 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, (vaddr_t) argp, NCARGS); 474 #else 475 kmem_free_wakeup(exec_map, (vaddr_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->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, (vaddr_t) argp, NCARGS); 512 #else 513 kmem_free_wakeup(exec_map, (vaddr_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, (vaddr_t) argp, NCARGS); 540 #else 541 kmem_free_wakeup(exec_map, (vaddr_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 Sun Sep 21 20:09:37 GMT 2025