kern_exec.c revision 1.67
1 /* $NetBSD: kern_exec.c,v 1.67 1995/04/22 19:42:52 christos 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 if (execsw[i].es_check != NULL) 148 error = (*execsw[i].es_check)(p, epp); 149 if (epp->ep_flags & EXEC_DESTR && error != 0) 150 return error; 151 } 152 if (!error) { 153 /* check that entry point is sane */ 154 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 155 error = ENOEXEC; 156 157 /* check limits */ 158 if ((epp->ep_tsize > MAXTSIZ) || 159 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 160 error = ENOMEM; 161 162 if (!error) 163 return (0); 164 } 165 166 /* 167 * free any vmspace-creation commands, 168 * and release their references 169 */ 170 kill_vmcmds(&epp->ep_vmcmds); 171 172 bad2: 173 /* 174 * unlock and close the vnode, restore the old one, free the 175 * pathname buf, and punt. 176 */ 177 VOP_UNLOCK(vp); 178 vn_close(vp, FREAD, p->p_ucred, p); 179 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 180 return error; 181 182 bad1: 183 /* 184 * free the namei pathname buffer, and put the vnode 185 * (which we don't yet have open). 186 */ 187 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 188 vput(vp); 189 return error; 190 } 191 192 /* 193 * exec system call 194 */ 195 /* ARGSUSED */ 196 execve(p, uap, retval) 197 register struct proc *p; 198 register struct execve_args /* { 199 syscallarg(char *) path; 200 syscallarg(char * *) argp; 201 syscallarg(char * *) envp; 202 } */ *uap; 203 register_t *retval; 204 { 205 int error, i; 206 struct exec_package pack; 207 struct nameidata nid; 208 struct vattr attr; 209 struct ucred *cred = p->p_ucred; 210 char *argp; 211 char **cpp, *dp, *sp; 212 long argc, envc; 213 size_t len; 214 char *stack; 215 struct ps_strings arginfo; 216 struct vmspace *vm = p->p_vmspace; 217 char **tmpfap; 218 int szsigcode; 219 extern struct emul emul_netbsd; 220 221 /* 222 * figure out the maximum size of an exec header, if necessary. 223 * XXX should be able to keep LKM code from modifying exec switch 224 * when we're still using it, but... 225 */ 226 if (exec_maxhdrsz == 0) { 227 for (i = 0; i < nexecs; i++) 228 if (execsw[i].es_check != NULL 229 && execsw[i].es_hdrsz > exec_maxhdrsz) 230 exec_maxhdrsz = execsw[i].es_hdrsz; 231 } 232 233 /* init the namei data to point the file user's program name */ 234 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 235 236 /* 237 * initialize the fields of the exec package. 238 */ 239 pack.ep_name = SCARG(uap, path); 240 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 241 pack.ep_hdrlen = exec_maxhdrsz; 242 pack.ep_hdrvalid = 0; 243 pack.ep_ndp = &nid; 244 pack.ep_emul_arg = NULL; 245 pack.ep_vmcmds.evs_cnt = 0; 246 pack.ep_vmcmds.evs_used = 0; 247 pack.ep_vap = &attr; 248 pack.ep_emul = &emul_netbsd; 249 pack.ep_flags = 0; 250 251 /* see if we can run it. */ 252 if (error = check_exec(p, &pack)) 253 goto freehdr; 254 255 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 256 257 /* allocate an argument buffer */ 258 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 259 #ifdef DIAGNOSTIC 260 if (argp == (vm_offset_t) 0) 261 panic("execve: argp == NULL"); 262 #endif 263 dp = argp; 264 argc = 0; 265 266 /* copy the fake args list, if there's one, freeing it as we go */ 267 if (pack.ep_flags & EXEC_HASARGL) { 268 tmpfap = pack.ep_fa; 269 while (*tmpfap != NULL) { 270 char *cp; 271 272 cp = *tmpfap; 273 while (*cp) 274 *dp++ = *cp++; 275 *dp++; 276 277 FREE(*tmpfap, M_EXEC); 278 tmpfap++; argc++; 279 } 280 FREE(pack.ep_fa, M_EXEC); 281 pack.ep_flags &= ~EXEC_HASARGL; 282 } 283 284 /* Now get argv & environment */ 285 if (!(cpp = SCARG(uap, argp))) { 286 error = EINVAL; 287 goto bad; 288 } 289 290 if (pack.ep_flags & EXEC_SKIPARG) 291 cpp++; 292 293 while (1) { 294 len = argp + ARG_MAX - dp; 295 if (error = copyin(cpp, &sp, sizeof(sp))) 296 goto bad; 297 if (!sp) 298 break; 299 if (error = copyinstr(sp, dp, len, &len)) { 300 if (error == ENAMETOOLONG) 301 error = E2BIG; 302 goto bad; 303 } 304 dp += len; 305 cpp++; 306 argc++; 307 } 308 309 envc = 0; 310 if (cpp = SCARG(uap, envp)) { /* environment need not be there */ 311 while (1) { 312 len = argp + ARG_MAX - dp; 313 if (error = copyin(cpp, &sp, sizeof(sp))) 314 goto bad; 315 if (!sp) 316 break; 317 if (error = copyinstr(sp, dp, len, &len)) { 318 if (error == ENAMETOOLONG) 319 error = E2BIG; 320 goto bad; 321 } 322 dp += len; 323 cpp++; 324 envc++; 325 } 326 } 327 328 dp = (char *) ALIGN(dp); 329 330 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 331 332 /* Now check if args & environ fit into new stack */ 333 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 334 sizeof(long) + dp + STACKGAPLEN + szsigcode + 335 sizeof(struct ps_strings)) - argp; 336 337 len = ALIGN(len); /* make the stack "safely" aligned */ 338 339 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 340 error = ENOMEM; 341 goto bad; 342 } 343 344 /* adjust "active stack depth" for process VSZ */ 345 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 346 347 /* Unmap old program */ 348 #ifdef sparc 349 kill_user_windows(p); /* before stack addresses go away */ 350 #endif 351 /* Kill shared memory and unmap old program */ 352 #ifdef SYSVSHM 353 if (vm->vm_shm) 354 shmexit(p); 355 #endif 356 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 357 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 358 359 /* Now map address space */ 360 vm->vm_taddr = (char *) pack.ep_taddr; 361 vm->vm_tsize = btoc(pack.ep_tsize); 362 vm->vm_daddr = (char *) pack.ep_daddr; 363 vm->vm_dsize = btoc(pack.ep_dsize); 364 vm->vm_ssize = btoc(pack.ep_ssize); 365 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 366 367 /* create the new process's VM space by running the vmcmds */ 368 #ifdef DIAGNOSTIC 369 if (pack.ep_vmcmds.evs_used == 0) 370 panic("execve: no vmcmds"); 371 #endif 372 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 373 struct exec_vmcmd *vcp; 374 375 vcp = &pack.ep_vmcmds.evs_cmds[i]; 376 error = (*vcp->ev_proc)(p, vcp); 377 } 378 379 /* free the vmspace-creation commands, and release their references */ 380 kill_vmcmds(&pack.ep_vmcmds); 381 382 /* if an error happened, deallocate and punt */ 383 if (error) 384 goto exec_abort; 385 386 /* remember information about the process */ 387 arginfo.ps_nargvstr = argc; 388 arginfo.ps_nenvstr = envc; 389 390 stack = (char *) (USRSTACK - len); 391 /* Now copy argc, args & environ to new stack */ 392 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 393 goto exec_abort; 394 395 /* copy out the process's ps_strings structure */ 396 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 397 goto exec_abort; 398 399 /* copy out the process's signal trapoline code */ 400 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 401 ((char *) PS_STRINGS) - szsigcode, 402 szsigcode)) 403 goto exec_abort; 404 405 fdcloseexec(p); /* handle close on exec */ 406 execsigs(p); /* reset catched signals */ 407 408 /* set command name & other accounting info */ 409 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 410 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 411 p->p_comm[len] = 0; 412 p->p_acflag &= ~AFORK; 413 414 /* record proc's vnode, for use by procfs and others */ 415 if (p->p_textvp) 416 vrele(p->p_textvp); 417 VREF(pack.ep_vp); 418 p->p_textvp = pack.ep_vp; 419 420 p->p_flag |= P_EXEC; 421 if (p->p_flag & P_PPWAIT) { 422 p->p_flag &= ~P_PPWAIT; 423 wakeup((caddr_t) p->p_pptr); 424 } 425 426 /* 427 * deal with set[ug]id. 428 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 429 */ 430 p->p_flag &= ~P_SUGID; 431 if (((attr.va_mode & VSUID) != 0 && 432 p->p_ucred->cr_uid != attr.va_uid) 433 || (attr.va_mode & VSGID) != 0 && 434 p->p_ucred->cr_gid != attr.va_gid) { 435 p->p_ucred = crcopy(cred); 436 #ifdef KTRACE 437 /* 438 * If process is being ktraced, turn off - unless 439 * root set it. 440 */ 441 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 442 vrele(p->p_tracep); 443 p->p_tracep = NULL; 444 p->p_traceflag = 0; 445 } 446 #endif 447 if (attr.va_mode & VSUID) 448 p->p_ucred->cr_uid = attr.va_uid; 449 if (attr.va_mode & VSGID) 450 p->p_ucred->cr_gid = attr.va_gid; 451 p->p_flag |= P_SUGID; 452 } 453 p->p_cred->p_svuid = p->p_ucred->cr_uid; 454 p->p_cred->p_svgid = p->p_ucred->cr_gid; 455 456 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 457 458 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 459 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 460 vput(pack.ep_vp); 461 462 /* setup new registers and do misc. setup. */ 463 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack, retval); 464 465 if (p->p_flag & P_TRACED) 466 psignal(p, SIGTRAP); 467 468 p->p_emul = pack.ep_emul; 469 FREE(pack.ep_hdr, M_EXEC); 470 return 0; 471 472 bad: 473 /* free the vmspace-creation commands, and release their references */ 474 kill_vmcmds(&pack.ep_vmcmds); 475 /* kill any opened file descriptor, if necessary */ 476 if (pack.ep_flags & EXEC_HASFD) { 477 pack.ep_flags &= ~EXEC_HASFD; 478 (void) fdrelease(p, pack.ep_fd); 479 } 480 /* close and put the exec'd file */ 481 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 482 vput(pack.ep_vp); 483 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 484 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 485 486 freehdr: 487 FREE(pack.ep_hdr, M_EXEC); 488 return error; 489 490 exec_abort: 491 /* 492 * the old process doesn't exist anymore. exit gracefully. 493 * get rid of the (new) address space we have created, if any, get rid 494 * of our namei data and vnode, and exit noting failure 495 */ 496 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 497 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 498 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 499 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 500 vput(pack.ep_vp); 501 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 502 FREE(pack.ep_hdr, M_EXEC); 503 exit1(p, W_EXITCODE(0, SIGABRT)); 504 exit1(p, -1); 505 506 /* NOTREACHED */ 507 return 0; 508 } 509 510 511 void * 512 copyargs(pack, arginfo, stack, argp) 513 struct exec_package *pack; 514 struct ps_strings *arginfo; 515 void *stack; 516 void *argp; 517 { 518 char **cpp = stack; 519 char *dp, *sp; 520 size_t len; 521 void *nullp = NULL; 522 int argc = arginfo->ps_nargvstr; 523 int envc = arginfo->ps_nenvstr; 524 525 if (copyout(&argc, cpp++, sizeof(argc))) 526 return NULL; 527 528 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 529 sp = argp; 530 531 /* XXX don't copy them out, remap them! */ 532 arginfo->ps_argvstr = dp; /* remember location of argv for later */ 533 534 for (; --argc >= 0; sp += len, dp += len) 535 if (copyout(&dp, cpp++, sizeof(dp)) || 536 copyoutstr(sp, dp, ARG_MAX, &len)) 537 return NULL; 538 539 if (copyout(&nullp, cpp++, sizeof(nullp))) 540 return NULL; 541 542 arginfo->ps_envstr = dp; /* remember location of envp for later */ 543 544 for (; --envc >= 0; sp += len, dp += len) 545 if (copyout(&dp, cpp++, sizeof(dp)) || 546 copyoutstr(sp, dp, ARG_MAX, &len)) 547 return NULL; 548 549 if (copyout(&nullp, cpp++, sizeof(nullp))) 550 return NULL; 551 552 return cpp; 553 } 554
Indexes created Tue Sep 23 02:09:52 GMT 2025