kern_exec.c revision 1.76
1 /* $NetBSD: kern_exec.c,v 1.76 1996/09/26 23:34:47 cgd Exp $ */ 2 3 /*- 4 * Copyright (C) 1993, 1994 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 (locked). 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 (locked). 84 * error: destructive: 85 * everything deallocated execept exec header. 86 * non-destructive: 87 * error code, executable's vnode (locked), 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 /* 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, IO_NODELOCKED, 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_UNLOCK(vp); 189 vn_close(vp, FREAD, p->p_ucred, p); 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 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 199 vput(vp); 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(char *) path; 215 syscallarg(char * *) argp; 216 syscallarg(char * *) 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 **cpp, *dp, *sp; 225 long argc, envc; 226 size_t len; 227 char *stack; 228 struct ps_strings arginfo; 229 struct vmspace *vm = p->p_vmspace; 230 char **tmpfap; 231 int szsigcode; 232 extern struct emul emul_netbsd; 233 234 /* 235 * figure out the maximum size of an exec header, if necessary. 236 * XXX should be able to keep LKM code from modifying exec switch 237 * when we're still using it, but... 238 */ 239 if (exec_maxhdrsz == 0) { 240 for (i = 0; i < nexecs; i++) 241 if (execsw[i].es_check != NULL 242 && execsw[i].es_hdrsz > exec_maxhdrsz) 243 exec_maxhdrsz = execsw[i].es_hdrsz; 244 } 245 246 /* init the namei data to point the file user's program name */ 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 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 272 #ifdef DIAGNOSTIC 273 if (argp == (vm_offset_t) 0) 274 panic("execve: argp == NULL"); 275 #endif 276 dp = argp; 277 argc = 0; 278 279 /* copy the fake args list, if there's one, freeing it as we go */ 280 if (pack.ep_flags & EXEC_HASARGL) { 281 tmpfap = pack.ep_fa; 282 while (*tmpfap != NULL) { 283 char *cp; 284 285 cp = *tmpfap; 286 while (*cp) 287 *dp++ = *cp++; 288 dp++; 289 290 FREE(*tmpfap, M_EXEC); 291 tmpfap++; argc++; 292 } 293 FREE(pack.ep_fa, M_EXEC); 294 pack.ep_flags &= ~EXEC_HASARGL; 295 } 296 297 /* Now get argv & environment */ 298 if (!(cpp = SCARG(uap, argp))) { 299 error = EINVAL; 300 goto bad; 301 } 302 303 if (pack.ep_flags & EXEC_SKIPARG) 304 cpp++; 305 306 while (1) { 307 len = argp + ARG_MAX - dp; 308 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 309 goto bad; 310 if (!sp) 311 break; 312 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 313 if (error == ENAMETOOLONG) 314 error = E2BIG; 315 goto bad; 316 } 317 dp += len; 318 cpp++; 319 argc++; 320 } 321 322 envc = 0; 323 /* environment need not be there */ 324 if ((cpp = SCARG(uap, envp)) != NULL ) { 325 while (1) { 326 len = argp + ARG_MAX - dp; 327 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 328 goto bad; 329 if (!sp) 330 break; 331 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 332 if (error == ENAMETOOLONG) 333 error = E2BIG; 334 goto bad; 335 } 336 dp += len; 337 cpp++; 338 envc++; 339 } 340 } 341 342 dp = (char *) ALIGN(dp); 343 344 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 345 346 /* Now check if args & environ fit into new stack */ 347 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 348 sizeof(long) + dp + STACKGAPLEN + szsigcode + 349 sizeof(struct ps_strings)) - argp; 350 351 len = ALIGN(len); /* make the stack "safely" aligned */ 352 353 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 354 error = ENOMEM; 355 goto bad; 356 } 357 358 /* adjust "active stack depth" for process VSZ */ 359 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 360 361 /* Unmap old program */ 362 #ifdef sparc 363 kill_user_windows(p); /* before stack addresses go away */ 364 #endif 365 /* Kill shared memory and unmap old program */ 366 #ifdef SYSVSHM 367 if (vm->vm_shm) 368 shmexit(p); 369 #endif 370 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 371 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 372 373 /* Now map address space */ 374 vm->vm_taddr = (char *) pack.ep_taddr; 375 vm->vm_tsize = btoc(pack.ep_tsize); 376 vm->vm_daddr = (char *) pack.ep_daddr; 377 vm->vm_dsize = btoc(pack.ep_dsize); 378 vm->vm_ssize = btoc(pack.ep_ssize); 379 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 380 381 /* create the new process's VM space by running the vmcmds */ 382 #ifdef DIAGNOSTIC 383 if (pack.ep_vmcmds.evs_used == 0) 384 panic("execve: no vmcmds"); 385 #endif 386 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 387 struct exec_vmcmd *vcp; 388 389 vcp = &pack.ep_vmcmds.evs_cmds[i]; 390 error = (*vcp->ev_proc)(p, vcp); 391 } 392 393 /* free the vmspace-creation commands, and release their references */ 394 kill_vmcmds(&pack.ep_vmcmds); 395 396 /* if an error happened, deallocate and punt */ 397 if (error) 398 goto exec_abort; 399 400 /* remember information about the process */ 401 arginfo.ps_nargvstr = argc; 402 arginfo.ps_nenvstr = envc; 403 404 stack = (char *) (USRSTACK - len); 405 /* Now copy argc, args & environ to new stack */ 406 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 407 goto exec_abort; 408 409 /* copy out the process's ps_strings structure */ 410 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 411 goto exec_abort; 412 413 /* copy out the process's signal trapoline code */ 414 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 415 ((char *) PS_STRINGS) - szsigcode, 416 szsigcode)) 417 goto exec_abort; 418 419 fdcloseexec(p); /* handle close on exec */ 420 execsigs(p); /* reset catched signals */ 421 422 /* set command name & other accounting info */ 423 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 424 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 425 p->p_comm[len] = 0; 426 p->p_acflag &= ~AFORK; 427 428 /* record proc's vnode, for use by procfs and others */ 429 if (p->p_textvp) 430 vrele(p->p_textvp); 431 VREF(pack.ep_vp); 432 p->p_textvp = pack.ep_vp; 433 434 p->p_flag |= P_EXEC; 435 if (p->p_flag & P_PPWAIT) { 436 p->p_flag &= ~P_PPWAIT; 437 wakeup((caddr_t) p->p_pptr); 438 } 439 440 /* 441 * deal with set[ug]id. 442 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 443 */ 444 p->p_flag &= ~P_SUGID; 445 if (((attr.va_mode & VSUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 446 || ((attr.va_mode & VSGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 447 p->p_ucred = crcopy(cred); 448 #ifdef KTRACE 449 /* 450 * If process is being ktraced, turn off - unless 451 * root set it. 452 */ 453 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 454 vrele(p->p_tracep); 455 p->p_tracep = NULL; 456 p->p_traceflag = 0; 457 } 458 #endif 459 if (attr.va_mode & VSUID) 460 p->p_ucred->cr_uid = attr.va_uid; 461 if (attr.va_mode & VSGID) 462 p->p_ucred->cr_gid = attr.va_gid; 463 p->p_flag |= P_SUGID; 464 } 465 p->p_cred->p_svuid = p->p_ucred->cr_uid; 466 p->p_cred->p_svgid = p->p_ucred->cr_gid; 467 468 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 469 470 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 471 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 472 vput(pack.ep_vp); 473 474 /* setup new registers and do misc. setup. */ 475 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack, retval); 476 477 if (p->p_flag & P_TRACED) 478 psignal(p, SIGTRAP); 479 480 p->p_emul = pack.ep_emul; 481 FREE(pack.ep_hdr, M_EXEC); 482 483 #ifdef KTRACE 484 if (KTRPOINT(p, KTR_EMUL)) 485 ktremul(p->p_tracep, p->p_emul->e_name); 486 #endif 487 return 0; 488 489 bad: 490 /* free the vmspace-creation commands, and release their references */ 491 kill_vmcmds(&pack.ep_vmcmds); 492 /* kill any opened file descriptor, if necessary */ 493 if (pack.ep_flags & EXEC_HASFD) { 494 pack.ep_flags &= ~EXEC_HASFD; 495 (void) fdrelease(p, pack.ep_fd); 496 } 497 /* close and put the exec'd file */ 498 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 499 vput(pack.ep_vp); 500 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 501 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 502 503 freehdr: 504 FREE(pack.ep_hdr, M_EXEC); 505 return error; 506 507 exec_abort: 508 /* 509 * the old process doesn't exist anymore. exit gracefully. 510 * get rid of the (new) address space we have created, if any, get rid 511 * of our namei data and vnode, and exit noting failure 512 */ 513 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 514 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 515 if (pack.ep_emul_arg) 516 FREE(pack.ep_emul_arg, M_TEMP); 517 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 518 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 519 vput(pack.ep_vp); 520 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 521 FREE(pack.ep_hdr, M_EXEC); 522 exit1(p, W_EXITCODE(0, SIGABRT)); 523 exit1(p, -1); 524 525 /* NOTREACHED */ 526 return 0; 527 } 528 529 530 void * 531 copyargs(pack, arginfo, stack, argp) 532 struct exec_package *pack; 533 struct ps_strings *arginfo; 534 void *stack; 535 void *argp; 536 { 537 char **cpp = stack; 538 char *dp, *sp; 539 size_t len; 540 void *nullp = NULL; 541 int argc = arginfo->ps_nargvstr; 542 int envc = arginfo->ps_nenvstr; 543 544 if (copyout(&argc, cpp++, sizeof(argc))) 545 return NULL; 546 547 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 548 sp = argp; 549 550 /* XXX don't copy them out, remap them! */ 551 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 552 553 for (; --argc >= 0; sp += len, dp += len) 554 if (copyout(&dp, cpp++, sizeof(dp)) || 555 copyoutstr(sp, dp, ARG_MAX, &len)) 556 return NULL; 557 558 if (copyout(&nullp, cpp++, sizeof(nullp))) 559 return NULL; 560 561 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 562 563 for (; --envc >= 0; sp += len, dp += len) 564 if (copyout(&dp, cpp++, sizeof(dp)) || 565 copyoutstr(sp, dp, ARG_MAX, &len)) 566 return NULL; 567 568 if (copyout(&nullp, cpp++, sizeof(nullp))) 569 return NULL; 570 571 return cpp; 572 } 573
Indexes created Sun Sep 21 20:09:37 GMT 2025