kern_exec.c revision 1.77
1 /* $NetBSD: kern_exec.c,v 1.77 1996/09/30 23:18:46 cgd 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 #ifdef SYSVSHM 54 #include <sys/shm.h> 55 #endif 56 57 #include <sys/syscallargs.h> 58 59 #include <vm/vm.h> 60 #include <vm/vm_kern.h> 61 62 #include <machine/cpu.h> 63 #include <machine/reg.h> 64 65 /* 66 * check exec: 67 * given an "executable" described in the exec package's namei info, 68 * see what we can do with it. 69 * 70 * ON ENTRY: 71 * exec package with appropriate namei info 72 * proc pointer of exec'ing proc 73 * NO SELF-LOCKED VNODES 74 * 75 * ON EXIT: 76 * error: nothing held, etc. exec header still allocated. 77 * ok: filled exec package, executable's vnode (unlocked). 78 * 79 * EXEC SWITCH ENTRY: 80 * Locked vnode to check, exec package, proc. 81 * 82 * EXEC SWITCH EXIT: 83 * ok: return 0, filled exec package, executable's vnode (unlocked). 84 * error: destructive: 85 * everything deallocated execept exec header. 86 * non-destructive: 87 * error code, executable's vnode (unlocked), 88 * exec header unmodified. 89 */ 90 int 91 check_exec(p, epp) 92 struct proc *p; 93 struct exec_package *epp; 94 { 95 int error, i; 96 struct vnode *vp; 97 struct nameidata *ndp; 98 int resid; 99 100 ndp = epp->ep_ndp; 101 ndp->ni_cnd.cn_nameiop = LOOKUP; 102 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 103 /* first get the vnode */ 104 if ((error = namei(ndp)) != 0) 105 return error; 106 epp->ep_vp = vp = ndp->ni_vp; 107 108 /* check for regular file */ 109 if (vp->v_type != VREG) { 110 error = EACCES; 111 goto bad1; 112 } 113 114 /* get attributes */ 115 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 116 goto bad1; 117 118 /* Check mount point */ 119 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 120 error = EACCES; 121 goto bad1; 122 } 123 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 124 epp->ep_vap->va_mode &= ~(VSUID | VSGID); 125 126 /* check access. for root we have to see if any exec bit on */ 127 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 128 goto bad1; 129 if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) { 130 error = EACCES; 131 goto bad1; 132 } 133 134 /* try to open it */ 135 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 136 goto bad1; 137 138 /* unlock vp, since we don't need it locked from here on out. */ 139 VOP_UNLOCK(vp); 140 141 /* now we have the file, get the exec header */ 142 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 143 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 144 if (error) 145 goto bad2; 146 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 147 148 /* 149 * set up the vmcmds for creation of the process 150 * address space 151 */ 152 error = ENOEXEC; 153 for (i = 0; i < nexecs && error != 0; i++) { 154 int newerror; 155 156 if (execsw[i].es_check == NULL) 157 continue; 158 159 newerror = (*execsw[i].es_check)(p, epp); 160 /* make sure the first "interesting" error code is saved. */ 161 if (!newerror || error == ENOEXEC) 162 error = newerror; 163 if (epp->ep_flags & EXEC_DESTR && error != 0) 164 return error; 165 } 166 if (!error) { 167 /* check that entry point is sane */ 168 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 169 error = ENOEXEC; 170 171 /* check limits */ 172 if ((epp->ep_tsize > MAXTSIZ) || 173 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 174 error = ENOMEM; 175 176 if (!error) 177 return (0); 178 } 179 180 /* 181 * free any vmspace-creation commands, 182 * and release their references 183 */ 184 kill_vmcmds(&epp->ep_vmcmds); 185 186 bad2: 187 /* 188 * unlock and close the vnode, restore the old one, free the 189 * pathname buf, and punt. 190 */ 191 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 192 vrele(vp); 193 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 194 return error; 195 196 bad1: 197 /* 198 * free the namei pathname buffer, and put the vnode 199 * (which we don't yet have open). 200 */ 201 vput(vp); /* was still locked */ 202 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 203 return error; 204 } 205 206 /* 207 * exec system call 208 */ 209 /* ARGSUSED */ 210 int 211 sys_execve(p, v, retval) 212 register struct proc *p; 213 void *v; 214 register_t *retval; 215 { 216 register struct sys_execve_args /* { 217 syscallarg(char *) path; 218 syscallarg(char * *) argp; 219 syscallarg(char * *) envp; 220 } */ *uap = v; 221 int error, i; 222 struct exec_package pack; 223 struct nameidata nid; 224 struct vattr attr; 225 struct ucred *cred = p->p_ucred; 226 char *argp; 227 char **cpp, *dp, *sp; 228 long argc, envc; 229 size_t len; 230 char *stack; 231 struct ps_strings arginfo; 232 struct vmspace *vm = p->p_vmspace; 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 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 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 /* Unmap old program */ 366 /* XXX cgd 960926: the sparc #ifdef should be a MD hook */ 367 #ifdef sparc 368 kill_user_windows(p); /* before stack addresses go away */ 369 #endif 370 /* Kill shared memory and unmap old program */ 371 #ifdef SYSVSHM 372 if (vm->vm_shm) 373 shmexit(p); 374 #endif 375 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 376 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 377 378 /* Now map address space */ 379 vm->vm_taddr = (char *) pack.ep_taddr; 380 vm->vm_tsize = btoc(pack.ep_tsize); 381 vm->vm_daddr = (char *) pack.ep_daddr; 382 vm->vm_dsize = btoc(pack.ep_dsize); 383 vm->vm_ssize = btoc(pack.ep_ssize); 384 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 385 386 /* create the new process's VM space by running the vmcmds */ 387 #ifdef DIAGNOSTIC 388 if (pack.ep_vmcmds.evs_used == 0) 389 panic("execve: no vmcmds"); 390 #endif 391 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 392 struct exec_vmcmd *vcp; 393 394 vcp = &pack.ep_vmcmds.evs_cmds[i]; 395 error = (*vcp->ev_proc)(p, vcp); 396 } 397 398 /* free the vmspace-creation commands, and release their references */ 399 kill_vmcmds(&pack.ep_vmcmds); 400 401 /* if an error happened, deallocate and punt */ 402 if (error) 403 goto exec_abort; 404 405 /* remember information about the process */ 406 arginfo.ps_nargvstr = argc; 407 arginfo.ps_nenvstr = envc; 408 409 stack = (char *) (USRSTACK - len); 410 /* Now copy argc, args & environ to new stack */ 411 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 412 goto exec_abort; 413 414 /* copy out the process's ps_strings structure */ 415 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 416 goto exec_abort; 417 418 /* copy out the process's signal trapoline code */ 419 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 420 ((char *) PS_STRINGS) - szsigcode, 421 szsigcode)) 422 goto exec_abort; 423 424 fdcloseexec(p); /* handle close on exec */ 425 execsigs(p); /* reset catched signals */ 426 427 /* set command name & other accounting info */ 428 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 429 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 430 p->p_comm[len] = 0; 431 p->p_acflag &= ~AFORK; 432 433 /* record proc's vnode, for use by procfs and others */ 434 if (p->p_textvp) 435 vrele(p->p_textvp); 436 VREF(pack.ep_vp); 437 p->p_textvp = pack.ep_vp; 438 439 p->p_flag |= P_EXEC; 440 if (p->p_flag & P_PPWAIT) { 441 p->p_flag &= ~P_PPWAIT; 442 wakeup((caddr_t) p->p_pptr); 443 } 444 445 /* 446 * deal with set[ug]id. 447 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 448 */ 449 p->p_flag &= ~P_SUGID; 450 if (((attr.va_mode & VSUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 451 || ((attr.va_mode & VSGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 452 p->p_ucred = crcopy(cred); 453 #ifdef KTRACE 454 /* 455 * If process is being ktraced, turn off - unless 456 * root set it. 457 */ 458 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 459 vrele(p->p_tracep); 460 p->p_tracep = NULL; 461 p->p_traceflag = 0; 462 } 463 #endif 464 if (attr.va_mode & VSUID) 465 p->p_ucred->cr_uid = attr.va_uid; 466 if (attr.va_mode & VSGID) 467 p->p_ucred->cr_gid = attr.va_gid; 468 p->p_flag |= P_SUGID; 469 } 470 p->p_cred->p_svuid = p->p_ucred->cr_uid; 471 p->p_cred->p_svgid = p->p_ucred->cr_gid; 472 473 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 474 475 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 476 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 477 vrele(pack.ep_vp); 478 479 /* setup new registers and do misc. setup. */ 480 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack, retval); 481 482 if (p->p_flag & P_TRACED) 483 psignal(p, SIGTRAP); 484 485 p->p_emul = pack.ep_emul; 486 FREE(pack.ep_hdr, M_EXEC); 487 488 #ifdef KTRACE 489 if (KTRPOINT(p, KTR_EMUL)) 490 ktremul(p->p_tracep, p->p_emul->e_name); 491 #endif 492 return 0; 493 494 bad: 495 /* free the vmspace-creation commands, and release their references */ 496 kill_vmcmds(&pack.ep_vmcmds); 497 /* kill any opened file descriptor, if necessary */ 498 if (pack.ep_flags & EXEC_HASFD) { 499 pack.ep_flags &= ~EXEC_HASFD; 500 (void) fdrelease(p, pack.ep_fd); 501 } 502 /* close and put the exec'd file */ 503 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 504 vrele(pack.ep_vp); 505 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 506 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 507 508 freehdr: 509 FREE(pack.ep_hdr, M_EXEC); 510 return error; 511 512 exec_abort: 513 /* 514 * the old process doesn't exist anymore. exit gracefully. 515 * get rid of the (new) address space we have created, if any, get rid 516 * of our namei data and vnode, and exit noting failure 517 */ 518 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 519 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 520 if (pack.ep_emul_arg) 521 FREE(pack.ep_emul_arg, M_TEMP); 522 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 523 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 524 vrele(pack.ep_vp); 525 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 526 FREE(pack.ep_hdr, M_EXEC); 527 exit1(p, W_EXITCODE(0, SIGABRT)); 528 exit1(p, -1); 529 530 /* NOTREACHED */ 531 return 0; 532 } 533 534 535 void * 536 copyargs(pack, arginfo, stack, argp) 537 struct exec_package *pack; 538 struct ps_strings *arginfo; 539 void *stack; 540 void *argp; 541 { 542 char **cpp = stack; 543 char *dp, *sp; 544 size_t len; 545 void *nullp = NULL; 546 int argc = arginfo->ps_nargvstr; 547 int envc = arginfo->ps_nenvstr; 548 549 if (copyout(&argc, cpp++, sizeof(argc))) 550 return NULL; 551 552 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 553 sp = argp; 554 555 /* XXX don't copy them out, remap them! */ 556 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 557 558 for (; --argc >= 0; sp += len, dp += len) 559 if (copyout(&dp, cpp++, sizeof(dp)) || 560 copyoutstr(sp, dp, ARG_MAX, &len)) 561 return NULL; 562 563 if (copyout(&nullp, cpp++, sizeof(nullp))) 564 return NULL; 565 566 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 567 568 for (; --envc >= 0; sp += len, dp += len) 569 if (copyout(&dp, cpp++, sizeof(dp)) || 570 copyoutstr(sp, dp, ARG_MAX, &len)) 571 return NULL; 572 573 if (copyout(&nullp, cpp++, sizeof(nullp))) 574 return NULL; 575 576 return cpp; 577 } 578
Indexes created Sun Sep 21 20:09:37 GMT 2025