kern_exec.c revision 1.90
1 /* $NetBSD: kern_exec.c,v 1.90 1998/03/01 02:22:28 fvdl 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_uvm.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 #if defined(UVM) 62 #include <uvm/uvm_extern.h> 63 #endif 64 65 #include <machine/cpu.h> 66 #include <machine/reg.h> 67 68 /* 69 * check exec: 70 * given an "executable" described in the exec package's namei info, 71 * see what we can do with it. 72 * 73 * ON ENTRY: 74 * exec package with appropriate namei info 75 * proc pointer of exec'ing proc 76 * NO SELF-LOCKED VNODES 77 * 78 * ON EXIT: 79 * error: nothing held, etc. exec header still allocated. 80 * ok: filled exec package, executable's vnode (unlocked). 81 * 82 * EXEC SWITCH ENTRY: 83 * Locked vnode to check, exec package, proc. 84 * 85 * EXEC SWITCH EXIT: 86 * ok: return 0, filled exec package, executable's vnode (unlocked). 87 * error: destructive: 88 * everything deallocated execept exec header. 89 * non-destructive: 90 * error code, executable's vnode (unlocked), 91 * exec header unmodified. 92 */ 93 int 94 check_exec(p, epp) 95 struct proc *p; 96 struct exec_package *epp; 97 { 98 int error, i; 99 struct vnode *vp; 100 struct nameidata *ndp; 101 int resid; 102 103 ndp = epp->ep_ndp; 104 ndp->ni_cnd.cn_nameiop = LOOKUP; 105 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 106 /* first get the vnode */ 107 if ((error = namei(ndp)) != 0) 108 return error; 109 epp->ep_vp = vp = ndp->ni_vp; 110 111 /* check access and type */ 112 if (vp->v_type != VREG) { 113 error = EACCES; 114 goto bad1; 115 } 116 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 117 goto bad1; 118 119 /* get attributes */ 120 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 121 goto bad1; 122 123 /* Check mount point */ 124 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 125 error = EACCES; 126 goto bad1; 127 } 128 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 129 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 130 131 /* try to open it */ 132 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 133 goto bad1; 134 135 /* unlock vp, since we don't need it locked from here on out. */ 136 VOP_UNLOCK(vp, 0); 137 138 /* now we have the file, get the exec header */ 139 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 140 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 141 if (error) 142 goto bad2; 143 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 144 145 /* 146 * set up the vmcmds for creation of the process 147 * address space 148 */ 149 error = ENOEXEC; 150 for (i = 0; i < nexecs && error != 0; i++) { 151 int newerror; 152 153 if (execsw[i].es_check == NULL) 154 continue; 155 156 newerror = (*execsw[i].es_check)(p, epp); 157 /* make sure the first "interesting" error code is saved. */ 158 if (!newerror || error == ENOEXEC) 159 error = newerror; 160 if (epp->ep_flags & EXEC_DESTR && error != 0) 161 return error; 162 } 163 if (!error) { 164 /* check that entry point is sane */ 165 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 166 error = ENOEXEC; 167 168 /* check limits */ 169 if ((epp->ep_tsize > MAXTSIZ) || 170 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 171 error = ENOMEM; 172 173 if (!error) 174 return (0); 175 } 176 177 /* 178 * free any vmspace-creation commands, 179 * and release their references 180 */ 181 kill_vmcmds(&epp->ep_vmcmds); 182 183 bad2: 184 /* 185 * unlock and close the vnode, restore the old one, free the 186 * pathname buf, and punt. 187 */ 188 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 189 vrele(vp); 190 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 191 return error; 192 193 bad1: 194 /* 195 * free the namei pathname buffer, and put the vnode 196 * (which we don't yet have open). 197 */ 198 vput(vp); /* was still locked */ 199 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 200 return error; 201 } 202 203 /* 204 * exec system call 205 */ 206 /* ARGSUSED */ 207 int 208 sys_execve(p, v, retval) 209 register struct proc *p; 210 void *v; 211 register_t *retval; 212 { 213 register struct sys_execve_args /* { 214 syscallarg(const char *) path; 215 syscallarg(char * const *) argp; 216 syscallarg(char * const *) envp; 217 } */ *uap = v; 218 int error, i; 219 struct exec_package pack; 220 struct nameidata nid; 221 struct vattr attr; 222 struct ucred *cred = p->p_ucred; 223 char *argp; 224 char * const *cpp; 225 char *dp, *sp; 226 long argc, envc; 227 size_t len; 228 char *stack; 229 struct ps_strings arginfo; 230 struct vmspace *vm; 231 char **tmpfap; 232 int szsigcode; 233 extern struct emul emul_netbsd; 234 235 /* 236 * figure out the maximum size of an exec header, if necessary. 237 * XXX should be able to keep LKM code from modifying exec switch 238 * when we're still using it, but... 239 */ 240 if (exec_maxhdrsz == 0) { 241 for (i = 0; i < nexecs; i++) 242 if (execsw[i].es_check != NULL 243 && execsw[i].es_hdrsz > exec_maxhdrsz) 244 exec_maxhdrsz = execsw[i].es_hdrsz; 245 } 246 247 /* init the namei data to point the file user's program name */ 248 /* XXX cgd 960926: why do this here? most will be clobbered. */ 249 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 250 251 /* 252 * initialize the fields of the exec package. 253 */ 254 pack.ep_name = SCARG(uap, path); 255 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 256 pack.ep_hdrlen = exec_maxhdrsz; 257 pack.ep_hdrvalid = 0; 258 pack.ep_ndp = &nid; 259 pack.ep_emul_arg = NULL; 260 pack.ep_vmcmds.evs_cnt = 0; 261 pack.ep_vmcmds.evs_used = 0; 262 pack.ep_vap = &attr; 263 pack.ep_emul = &emul_netbsd; 264 pack.ep_flags = 0; 265 266 /* see if we can run it. */ 267 if ((error = check_exec(p, &pack)) != 0) 268 goto freehdr; 269 270 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 271 272 /* allocate an argument buffer */ 273 #if defined(UVM) 274 argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS); 275 #else 276 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 277 #endif 278 #ifdef DIAGNOSTIC 279 if (argp == (vm_offset_t) 0) 280 panic("execve: argp == NULL"); 281 #endif 282 dp = argp; 283 argc = 0; 284 285 /* copy the fake args list, if there's one, freeing it as we go */ 286 if (pack.ep_flags & EXEC_HASARGL) { 287 tmpfap = pack.ep_fa; 288 while (*tmpfap != NULL) { 289 char *cp; 290 291 cp = *tmpfap; 292 while (*cp) 293 *dp++ = *cp++; 294 dp++; 295 296 FREE(*tmpfap, M_EXEC); 297 tmpfap++; argc++; 298 } 299 FREE(pack.ep_fa, M_EXEC); 300 pack.ep_flags &= ~EXEC_HASARGL; 301 } 302 303 /* Now get argv & environment */ 304 if (!(cpp = SCARG(uap, argp))) { 305 error = EINVAL; 306 goto bad; 307 } 308 309 if (pack.ep_flags & EXEC_SKIPARG) 310 cpp++; 311 312 while (1) { 313 len = argp + ARG_MAX - dp; 314 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 315 goto bad; 316 if (!sp) 317 break; 318 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 319 if (error == ENAMETOOLONG) 320 error = E2BIG; 321 goto bad; 322 } 323 dp += len; 324 cpp++; 325 argc++; 326 } 327 328 envc = 0; 329 /* environment need not be there */ 330 if ((cpp = SCARG(uap, envp)) != NULL ) { 331 while (1) { 332 len = argp + ARG_MAX - dp; 333 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 334 goto bad; 335 if (!sp) 336 break; 337 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 338 if (error == ENAMETOOLONG) 339 error = E2BIG; 340 goto bad; 341 } 342 dp += len; 343 cpp++; 344 envc++; 345 } 346 } 347 348 dp = (char *) ALIGN(dp); 349 350 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 351 352 /* Now check if args & environ fit into new stack */ 353 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 354 sizeof(long) + 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 #if defined(UVM) 373 uvmspace_exec(p); 374 #else 375 vmspace_exec(p); 376 #endif 377 378 /* Now map address space */ 379 vm = p->p_vmspace; 380 vm->vm_taddr = (char *) pack.ep_taddr; 381 vm->vm_tsize = btoc(pack.ep_tsize); 382 vm->vm_daddr = (char *) pack.ep_daddr; 383 vm->vm_dsize = btoc(pack.ep_dsize); 384 vm->vm_ssize = btoc(pack.ep_ssize); 385 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 386 387 /* create the new process's VM space by running the vmcmds */ 388 #ifdef DIAGNOSTIC 389 if (pack.ep_vmcmds.evs_used == 0) 390 panic("execve: no vmcmds"); 391 #endif 392 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 393 struct exec_vmcmd *vcp; 394 395 vcp = &pack.ep_vmcmds.evs_cmds[i]; 396 error = (*vcp->ev_proc)(p, vcp); 397 } 398 399 /* free the vmspace-creation commands, and release their references */ 400 kill_vmcmds(&pack.ep_vmcmds); 401 402 /* if an error happened, deallocate and punt */ 403 if (error) 404 goto exec_abort; 405 406 /* remember information about the process */ 407 arginfo.ps_nargvstr = argc; 408 arginfo.ps_nenvstr = envc; 409 410 stack = (char *) (USRSTACK - len); 411 /* Now copy argc, args & environ to new stack */ 412 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 413 goto exec_abort; 414 415 /* copy out the process's ps_strings structure */ 416 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 417 goto exec_abort; 418 419 /* copy out the process's signal trapoline code */ 420 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 421 ((char *) PS_STRINGS) - szsigcode, 422 szsigcode)) 423 goto exec_abort; 424 425 fdcloseexec(p); /* handle close on exec */ 426 execsigs(p); /* reset catched signals */ 427 428 /* set command name & other accounting info */ 429 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 430 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 431 p->p_comm[len] = 0; 432 p->p_acflag &= ~AFORK; 433 434 /* record proc's vnode, for use by procfs and others */ 435 if (p->p_textvp) 436 vrele(p->p_textvp); 437 VREF(pack.ep_vp); 438 p->p_textvp = pack.ep_vp; 439 440 p->p_flag |= P_EXEC; 441 if (p->p_flag & P_PPWAIT) { 442 p->p_flag &= ~P_PPWAIT; 443 wakeup((caddr_t) p->p_pptr); 444 } 445 446 /* 447 * deal with set[ug]id. 448 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 449 */ 450 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 451 || ((attr.va_mode & S_ISGID) != 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 & S_ISUID) 465 p->p_ucred->cr_uid = attr.va_uid; 466 if (attr.va_mode & S_ISGID) 467 p->p_ucred->cr_gid = attr.va_gid; 468 p->p_flag |= P_SUGID; 469 } else 470 p->p_flag &= ~P_SUGID; 471 p->p_cred->p_svuid = p->p_ucred->cr_uid; 472 p->p_cred->p_svgid = p->p_ucred->cr_gid; 473 474 #if defined(UVM) 475 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 476 #else 477 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 478 #endif 479 480 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 481 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 482 vrele(pack.ep_vp); 483 484 /* setup new registers and do misc. setup. */ 485 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 486 487 if (p->p_flag & P_TRACED) 488 psignal(p, SIGTRAP); 489 490 p->p_emul = pack.ep_emul; 491 FREE(pack.ep_hdr, M_EXEC); 492 493 #ifdef KTRACE 494 if (KTRPOINT(p, KTR_EMUL)) 495 ktremul(p->p_tracep, p->p_emul->e_name); 496 #endif 497 498 return (EJUSTRETURN); 499 500 bad: 501 /* free the vmspace-creation commands, and release their references */ 502 kill_vmcmds(&pack.ep_vmcmds); 503 /* kill any opened file descriptor, if necessary */ 504 if (pack.ep_flags & EXEC_HASFD) { 505 pack.ep_flags &= ~EXEC_HASFD; 506 (void) fdrelease(p, pack.ep_fd); 507 } 508 /* close and put the exec'd file */ 509 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 510 vrele(pack.ep_vp); 511 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 512 #if defined(UVM) 513 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 514 #else 515 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 516 #endif 517 518 freehdr: 519 FREE(pack.ep_hdr, M_EXEC); 520 return error; 521 522 exec_abort: 523 /* 524 * the old process doesn't exist anymore. exit gracefully. 525 * get rid of the (new) address space we have created, if any, get rid 526 * of our namei data and vnode, and exit noting failure 527 */ 528 #if defined(UVM) 529 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 530 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 531 #else 532 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 533 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 534 #endif 535 if (pack.ep_emul_arg) 536 FREE(pack.ep_emul_arg, M_TEMP); 537 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 538 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 539 vrele(pack.ep_vp); 540 #if defined(UVM) 541 uvm_km_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 542 #else 543 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 544 #endif 545 FREE(pack.ep_hdr, M_EXEC); 546 exit1(p, W_EXITCODE(0, SIGABRT)); 547 exit1(p, -1); 548 549 /* NOTREACHED */ 550 return 0; 551 } 552 553 554 void * 555 copyargs(pack, arginfo, stack, argp) 556 struct exec_package *pack; 557 struct ps_strings *arginfo; 558 void *stack; 559 void *argp; 560 { 561 char **cpp = stack; 562 char *dp, *sp; 563 size_t len; 564 void *nullp = NULL; 565 int argc = arginfo->ps_nargvstr; 566 int envc = arginfo->ps_nenvstr; 567 568 if (copyout(&argc, cpp++, sizeof(argc))) 569 return NULL; 570 571 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 572 sp = argp; 573 574 /* XXX don't copy them out, remap them! */ 575 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 576 577 for (; --argc >= 0; sp += len, dp += len) 578 if (copyout(&dp, cpp++, sizeof(dp)) || 579 copyoutstr(sp, dp, ARG_MAX, &len)) 580 return NULL; 581 582 if (copyout(&nullp, cpp++, sizeof(nullp))) 583 return NULL; 584 585 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 586 587 for (; --envc >= 0; sp += len, dp += len) 588 if (copyout(&dp, cpp++, sizeof(dp)) || 589 copyoutstr(sp, dp, ARG_MAX, &len)) 590 return NULL; 591 592 if (copyout(&nullp, cpp++, sizeof(nullp))) 593 return NULL; 594 595 return cpp; 596 } 597
Indexes created Sun Sep 21 20:09:37 GMT 2025