kern_exec.c revision 1.73
1 /* $NetBSD: kern_exec.c,v 1.73 1995/12/09 04:11:00 mycroft 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 54 #include <sys/syscallargs.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_kern.h> 58 59 #include <machine/cpu.h> 60 #include <machine/reg.h> 61 62 /* 63 * check exec: 64 * given an "executable" described in the exec package's namei info, 65 * see what we can do with it. 66 * 67 * ON ENTRY: 68 * exec package with appropriate namei info 69 * proc pointer of exec'ing proc 70 * NO SELF-LOCKED VNODES 71 * 72 * ON EXIT: 73 * error: nothing held, etc. exec header still allocated. 74 * ok: filled exec package, one locked vnode. 75 * 76 * EXEC SWITCH ENTRY: 77 * Locked vnode to check, exec package, proc. 78 * 79 * EXEC SWITCH EXIT: 80 * ok: return 0, filled exec package, one locked vnode. 81 * error: destructive: 82 * everything deallocated execept exec header. 83 * non-descructive: 84 * error code, locked vnode, exec header unmodified 85 */ 86 int 87 check_exec(p, epp) 88 struct proc *p; 89 struct exec_package *epp; 90 { 91 int error, i; 92 struct vnode *vp; 93 char *cp, *ep, *name; 94 struct nameidata *ndp; 95 int resid; 96 97 ndp = epp->ep_ndp; 98 ndp->ni_cnd.cn_nameiop = LOOKUP; 99 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 100 /* first get the vnode */ 101 if (error = namei(ndp)) 102 return error; 103 epp->ep_vp = vp = ndp->ni_vp; 104 105 /* check for regular file */ 106 if (vp->v_type != VREG) { 107 error = EACCES; 108 goto bad1; 109 } 110 111 /* get attributes */ 112 if (error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) 113 goto bad1; 114 115 /* Check mount point */ 116 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 117 error = EACCES; 118 goto bad1; 119 } 120 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 121 epp->ep_vap->va_mode &= ~(VSUID | VSGID); 122 123 /* check access. for root we have to see if any exec bit on */ 124 if (error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) 125 goto bad1; 126 if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) { 127 error = EACCES; 128 goto bad1; 129 } 130 131 /* try to open it */ 132 if (error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) 133 goto bad1; 134 135 /* now we have the file, get the exec header */ 136 if (error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 137 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p)) 138 goto bad2; 139 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 140 141 /* 142 * set up the vmcmds for creation of the process 143 * address space 144 */ 145 error = ENOEXEC; 146 for (i = 0; i < nexecs && error != 0; i++) { 147 int newerror; 148 149 if (execsw[i].es_check == NULL) 150 continue; 151 152 newerror = (*execsw[i].es_check)(p, epp); 153 /* make sure the first "interesting" error code is saved. */ 154 if (!newerror || error == ENOEXEC) 155 error = newerror; 156 if (epp->ep_flags & EXEC_DESTR && error != 0) 157 return error; 158 } 159 if (!error) { 160 /* check that entry point is sane */ 161 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 162 error = ENOEXEC; 163 164 /* check limits */ 165 if ((epp->ep_tsize > MAXTSIZ) || 166 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 167 error = ENOMEM; 168 169 if (!error) 170 return (0); 171 } 172 173 /* 174 * free any vmspace-creation commands, 175 * and release their references 176 */ 177 kill_vmcmds(&epp->ep_vmcmds); 178 179 bad2: 180 /* 181 * unlock and close the vnode, restore the old one, free the 182 * pathname buf, and punt. 183 */ 184 VOP_UNLOCK(vp); 185 vn_close(vp, FREAD, p->p_ucred, p); 186 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 187 return error; 188 189 bad1: 190 /* 191 * free the namei pathname buffer, and put the vnode 192 * (which we don't yet have open). 193 */ 194 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 195 vput(vp); 196 return error; 197 } 198 199 /* 200 * exec system call 201 */ 202 /* ARGSUSED */ 203 sys_execve(p, v, retval) 204 register struct proc *p; 205 void *v; 206 register_t *retval; 207 { 208 register struct sys_execve_args /* { 209 syscallarg(char *) path; 210 syscallarg(char * *) argp; 211 syscallarg(char * *) envp; 212 } */ *uap = v; 213 int error, i; 214 struct exec_package pack; 215 struct nameidata nid; 216 struct vattr attr; 217 struct ucred *cred = p->p_ucred; 218 char *argp; 219 char **cpp, *dp, *sp; 220 long argc, envc; 221 size_t len; 222 char *stack; 223 struct ps_strings arginfo; 224 struct vmspace *vm = p->p_vmspace; 225 char **tmpfap; 226 int szsigcode; 227 extern struct emul emul_netbsd; 228 229 /* 230 * figure out the maximum size of an exec header, if necessary. 231 * XXX should be able to keep LKM code from modifying exec switch 232 * when we're still using it, but... 233 */ 234 if (exec_maxhdrsz == 0) { 235 for (i = 0; i < nexecs; i++) 236 if (execsw[i].es_check != NULL 237 && execsw[i].es_hdrsz > exec_maxhdrsz) 238 exec_maxhdrsz = execsw[i].es_hdrsz; 239 } 240 241 /* init the namei data to point the file user's program name */ 242 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 243 244 /* 245 * initialize the fields of the exec package. 246 */ 247 pack.ep_name = SCARG(uap, path); 248 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 249 pack.ep_hdrlen = exec_maxhdrsz; 250 pack.ep_hdrvalid = 0; 251 pack.ep_ndp = &nid; 252 pack.ep_emul_arg = NULL; 253 pack.ep_vmcmds.evs_cnt = 0; 254 pack.ep_vmcmds.evs_used = 0; 255 pack.ep_vap = &attr; 256 pack.ep_emul = &emul_netbsd; 257 pack.ep_flags = 0; 258 259 /* see if we can run it. */ 260 if (error = check_exec(p, &pack)) 261 goto freehdr; 262 263 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 264 265 /* allocate an argument buffer */ 266 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 267 #ifdef DIAGNOSTIC 268 if (argp == (vm_offset_t) 0) 269 panic("execve: argp == NULL"); 270 #endif 271 dp = argp; 272 argc = 0; 273 274 /* copy the fake args list, if there's one, freeing it as we go */ 275 if (pack.ep_flags & EXEC_HASARGL) { 276 tmpfap = pack.ep_fa; 277 while (*tmpfap != NULL) { 278 char *cp; 279 280 cp = *tmpfap; 281 while (*cp) 282 *dp++ = *cp++; 283 *dp++; 284 285 FREE(*tmpfap, M_EXEC); 286 tmpfap++; argc++; 287 } 288 FREE(pack.ep_fa, M_EXEC); 289 pack.ep_flags &= ~EXEC_HASARGL; 290 } 291 292 /* Now get argv & environment */ 293 if (!(cpp = SCARG(uap, argp))) { 294 error = EINVAL; 295 goto bad; 296 } 297 298 if (pack.ep_flags & EXEC_SKIPARG) 299 cpp++; 300 301 while (1) { 302 len = argp + ARG_MAX - dp; 303 if (error = copyin(cpp, &sp, sizeof(sp))) 304 goto bad; 305 if (!sp) 306 break; 307 if (error = copyinstr(sp, dp, len, &len)) { 308 if (error == ENAMETOOLONG) 309 error = E2BIG; 310 goto bad; 311 } 312 dp += len; 313 cpp++; 314 argc++; 315 } 316 317 envc = 0; 318 if (cpp = SCARG(uap, envp)) { /* environment need not be there */ 319 while (1) { 320 len = argp + ARG_MAX - dp; 321 if (error = copyin(cpp, &sp, sizeof(sp))) 322 goto bad; 323 if (!sp) 324 break; 325 if (error = copyinstr(sp, dp, len, &len)) { 326 if (error == ENAMETOOLONG) 327 error = E2BIG; 328 goto bad; 329 } 330 dp += len; 331 cpp++; 332 envc++; 333 } 334 } 335 336 dp = (char *) ALIGN(dp); 337 338 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 339 340 /* Now check if args & environ fit into new stack */ 341 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 342 sizeof(long) + dp + STACKGAPLEN + szsigcode + 343 sizeof(struct ps_strings)) - argp; 344 345 len = ALIGN(len); /* make the stack "safely" aligned */ 346 347 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 348 error = ENOMEM; 349 goto bad; 350 } 351 352 /* adjust "active stack depth" for process VSZ */ 353 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 354 355 /* Unmap old program */ 356 #ifdef sparc 357 kill_user_windows(p); /* before stack addresses go away */ 358 #endif 359 /* Kill shared memory and unmap old program */ 360 #ifdef SYSVSHM 361 if (vm->vm_shm) 362 shmexit(p); 363 #endif 364 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 365 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 366 367 /* Now map address space */ 368 vm->vm_taddr = (char *) pack.ep_taddr; 369 vm->vm_tsize = btoc(pack.ep_tsize); 370 vm->vm_daddr = (char *) pack.ep_daddr; 371 vm->vm_dsize = btoc(pack.ep_dsize); 372 vm->vm_ssize = btoc(pack.ep_ssize); 373 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 374 375 /* create the new process's VM space by running the vmcmds */ 376 #ifdef DIAGNOSTIC 377 if (pack.ep_vmcmds.evs_used == 0) 378 panic("execve: no vmcmds"); 379 #endif 380 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 381 struct exec_vmcmd *vcp; 382 383 vcp = &pack.ep_vmcmds.evs_cmds[i]; 384 error = (*vcp->ev_proc)(p, vcp); 385 } 386 387 /* free the vmspace-creation commands, and release their references */ 388 kill_vmcmds(&pack.ep_vmcmds); 389 390 /* if an error happened, deallocate and punt */ 391 if (error) 392 goto exec_abort; 393 394 /* remember information about the process */ 395 arginfo.ps_nargvstr = argc; 396 arginfo.ps_nenvstr = envc; 397 398 stack = (char *) (USRSTACK - len); 399 /* Now copy argc, args & environ to new stack */ 400 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 401 goto exec_abort; 402 403 /* copy out the process's ps_strings structure */ 404 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 405 goto exec_abort; 406 407 /* copy out the process's signal trapoline code */ 408 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 409 ((char *) PS_STRINGS) - szsigcode, 410 szsigcode)) 411 goto exec_abort; 412 413 fdcloseexec(p); /* handle close on exec */ 414 execsigs(p); /* reset catched signals */ 415 416 /* set command name & other accounting info */ 417 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 418 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 419 p->p_comm[len] = 0; 420 p->p_acflag &= ~AFORK; 421 422 /* record proc's vnode, for use by procfs and others */ 423 if (p->p_textvp) 424 vrele(p->p_textvp); 425 VREF(pack.ep_vp); 426 p->p_textvp = pack.ep_vp; 427 428 p->p_flag |= P_EXEC; 429 if (p->p_flag & P_PPWAIT) { 430 p->p_flag &= ~P_PPWAIT; 431 wakeup((caddr_t) p->p_pptr); 432 } 433 434 /* 435 * deal with set[ug]id. 436 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 437 */ 438 p->p_flag &= ~P_SUGID; 439 if (((attr.va_mode & VSUID) != 0 && 440 p->p_ucred->cr_uid != attr.va_uid) 441 || (attr.va_mode & VSGID) != 0 && 442 p->p_ucred->cr_gid != attr.va_gid) { 443 p->p_ucred = crcopy(cred); 444 #ifdef KTRACE 445 /* 446 * If process is being ktraced, turn off - unless 447 * root set it. 448 */ 449 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 450 vrele(p->p_tracep); 451 p->p_tracep = NULL; 452 p->p_traceflag = 0; 453 } 454 #endif 455 if (attr.va_mode & VSUID) 456 p->p_ucred->cr_uid = attr.va_uid; 457 if (attr.va_mode & VSGID) 458 p->p_ucred->cr_gid = attr.va_gid; 459 p->p_flag |= P_SUGID; 460 } 461 p->p_cred->p_svuid = p->p_ucred->cr_uid; 462 p->p_cred->p_svgid = p->p_ucred->cr_gid; 463 464 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 465 466 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 467 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 468 vput(pack.ep_vp); 469 470 /* setup new registers and do misc. setup. */ 471 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack, retval); 472 473 if (p->p_flag & P_TRACED) 474 psignal(p, SIGTRAP); 475 476 p->p_emul = pack.ep_emul; 477 FREE(pack.ep_hdr, M_EXEC); 478 479 #ifdef KTRACE 480 if (KTRPOINT(p, KTR_EMUL)) 481 ktremul(p->p_tracep, p->p_emul->e_name); 482 #endif 483 return 0; 484 485 bad: 486 /* free the vmspace-creation commands, and release their references */ 487 kill_vmcmds(&pack.ep_vmcmds); 488 /* kill any opened file descriptor, if necessary */ 489 if (pack.ep_flags & EXEC_HASFD) { 490 pack.ep_flags &= ~EXEC_HASFD; 491 (void) fdrelease(p, pack.ep_fd); 492 } 493 /* close and put the exec'd file */ 494 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 495 vput(pack.ep_vp); 496 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 497 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 498 499 freehdr: 500 FREE(pack.ep_hdr, M_EXEC); 501 return error; 502 503 exec_abort: 504 /* 505 * the old process doesn't exist anymore. exit gracefully. 506 * get rid of the (new) address space we have created, if any, get rid 507 * of our namei data and vnode, and exit noting failure 508 */ 509 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 510 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 511 if (pack.ep_emul_arg) 512 FREE(pack.ep_emul_arg, M_TEMP); 513 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 514 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 515 vput(pack.ep_vp); 516 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 517 FREE(pack.ep_hdr, M_EXEC); 518 exit1(p, W_EXITCODE(0, SIGABRT)); 519 exit1(p, -1); 520 521 /* NOTREACHED */ 522 return 0; 523 } 524 525 526 void * 527 copyargs(pack, arginfo, stack, argp) 528 struct exec_package *pack; 529 struct ps_strings *arginfo; 530 void *stack; 531 void *argp; 532 { 533 char **cpp = stack; 534 char *dp, *sp; 535 size_t len; 536 void *nullp = NULL; 537 int argc = arginfo->ps_nargvstr; 538 int envc = arginfo->ps_nenvstr; 539 540 if (copyout(&argc, cpp++, sizeof(argc))) 541 return NULL; 542 543 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 544 sp = argp; 545 546 /* XXX don't copy them out, remap them! */ 547 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 548 549 for (; --argc >= 0; sp += len, dp += len) 550 if (copyout(&dp, cpp++, sizeof(dp)) || 551 copyoutstr(sp, dp, ARG_MAX, &len)) 552 return NULL; 553 554 if (copyout(&nullp, cpp++, sizeof(nullp))) 555 return NULL; 556 557 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 558 559 for (; --envc >= 0; sp += len, dp += len) 560 if (copyout(&dp, cpp++, sizeof(dp)) || 561 copyoutstr(sp, dp, ARG_MAX, &len)) 562 return NULL; 563 564 if (copyout(&nullp, cpp++, sizeof(nullp))) 565 return NULL; 566 567 return cpp; 568 } 569
Indexes created Tue Sep 23 01:09:51 GMT 2025