1 /* $NetBSD: kern_exec.c,v 1.87 1998/01/01 02:43:18 enami 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 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, executable's vnode (unlocked). 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, executable's vnode (unlocked). 81 * error: destructive: 82 * everything deallocated execept exec header. 83 * non-destructive: 84 * error code, executable's vnode (unlocked), 85 * exec header unmodified. 86 */ 87 int 88 check_exec(p, epp) 89 struct proc *p; 90 struct exec_package *epp; 91 { 92 int error, i; 93 struct vnode *vp; 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)) != 0) 102 return error; 103 epp->ep_vp = vp = ndp->ni_vp; 104 105 /* check access and type */ 106 if (vp->v_type != VREG) { 107 error = EACCES; 108 goto bad1; 109 } 110 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 111 goto bad1; 112 113 /* get attributes */ 114 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 115 goto bad1; 116 117 /* Check mount point */ 118 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 119 error = EACCES; 120 goto bad1; 121 } 122 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 123 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 124 125 /* try to open it */ 126 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 127 goto bad1; 128 129 /* unlock vp, since we don't need it locked from here on out. */ 130 VOP_UNLOCK(vp); 131 132 /* now we have the file, get the exec header */ 133 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 134 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 135 if (error) 136 goto bad2; 137 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 138 139 /* 140 * set up the vmcmds for creation of the process 141 * address space 142 */ 143 error = ENOEXEC; 144 for (i = 0; i < nexecs && error != 0; i++) { 145 int newerror; 146 147 if (execsw[i].es_check == NULL) 148 continue; 149 150 newerror = (*execsw[i].es_check)(p, epp); 151 /* make sure the first "interesting" error code is saved. */ 152 if (!newerror || error == ENOEXEC) 153 error = newerror; 154 if (epp->ep_flags & EXEC_DESTR && error != 0) 155 return error; 156 } 157 if (!error) { 158 /* check that entry point is sane */ 159 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 160 error = ENOEXEC; 161 162 /* check limits */ 163 if ((epp->ep_tsize > MAXTSIZ) || 164 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 165 error = ENOMEM; 166 167 if (!error) 168 return (0); 169 } 170 171 /* 172 * free any vmspace-creation commands, 173 * and release their references 174 */ 175 kill_vmcmds(&epp->ep_vmcmds); 176 177 bad2: 178 /* 179 * unlock and close the vnode, restore the old one, free the 180 * pathname buf, and punt. 181 */ 182 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 183 vrele(vp); 184 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 185 return error; 186 187 bad1: 188 /* 189 * free the namei pathname buffer, and put the vnode 190 * (which we don't yet have open). 191 */ 192 vput(vp); /* was still locked */ 193 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 194 return error; 195 } 196 197 /* 198 * exec system call 199 */ 200 /* ARGSUSED */ 201 int 202 sys_execve(p, v, retval) 203 register struct proc *p; 204 void *v; 205 register_t *retval; 206 { 207 register struct sys_execve_args /* { 208 syscallarg(const char *) path; 209 syscallarg(char * const *) argp; 210 syscallarg(char * const *) envp; 211 } */ *uap = v; 212 int error, i; 213 struct exec_package pack; 214 struct nameidata nid; 215 struct vattr attr; 216 struct ucred *cred = p->p_ucred; 217 char *argp; 218 char * const *cpp; 219 char *dp, *sp; 220 long argc, envc; 221 size_t len; 222 char *stack; 223 struct ps_strings arginfo; 224 struct vmspace *vm; 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 /* XXX cgd 960926: why do this here? most will be clobbered. */ 243 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 244 245 /* 246 * initialize the fields of the exec package. 247 */ 248 pack.ep_name = SCARG(uap, path); 249 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 250 pack.ep_hdrlen = exec_maxhdrsz; 251 pack.ep_hdrvalid = 0; 252 pack.ep_ndp = &nid; 253 pack.ep_emul_arg = NULL; 254 pack.ep_vmcmds.evs_cnt = 0; 255 pack.ep_vmcmds.evs_used = 0; 256 pack.ep_vap = &attr; 257 pack.ep_emul = &emul_netbsd; 258 pack.ep_flags = 0; 259 260 /* see if we can run it. */ 261 if ((error = check_exec(p, &pack)) != 0) 262 goto freehdr; 263 264 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 265 266 /* allocate an argument buffer */ 267 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 268 #ifdef DIAGNOSTIC 269 if (argp == (vm_offset_t) 0) 270 panic("execve: argp == NULL"); 271 #endif 272 dp = argp; 273 argc = 0; 274 275 /* copy the fake args list, if there's one, freeing it as we go */ 276 if (pack.ep_flags & EXEC_HASARGL) { 277 tmpfap = pack.ep_fa; 278 while (*tmpfap != NULL) { 279 char *cp; 280 281 cp = *tmpfap; 282 while (*cp) 283 *dp++ = *cp++; 284 dp++; 285 286 FREE(*tmpfap, M_EXEC); 287 tmpfap++; argc++; 288 } 289 FREE(pack.ep_fa, M_EXEC); 290 pack.ep_flags &= ~EXEC_HASARGL; 291 } 292 293 /* Now get argv & environment */ 294 if (!(cpp = SCARG(uap, argp))) { 295 error = EINVAL; 296 goto bad; 297 } 298 299 if (pack.ep_flags & EXEC_SKIPARG) 300 cpp++; 301 302 while (1) { 303 len = argp + ARG_MAX - dp; 304 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 305 goto bad; 306 if (!sp) 307 break; 308 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 309 if (error == ENAMETOOLONG) 310 error = E2BIG; 311 goto bad; 312 } 313 dp += len; 314 cpp++; 315 argc++; 316 } 317 318 envc = 0; 319 /* environment need not be there */ 320 if ((cpp = SCARG(uap, envp)) != NULL ) { 321 while (1) { 322 len = argp + ARG_MAX - dp; 323 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 324 goto bad; 325 if (!sp) 326 break; 327 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 328 if (error == ENAMETOOLONG) 329 error = E2BIG; 330 goto bad; 331 } 332 dp += len; 333 cpp++; 334 envc++; 335 } 336 } 337 338 dp = (char *) ALIGN(dp); 339 340 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 341 342 /* Now check if args & environ fit into new stack */ 343 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 344 sizeof(long) + dp + STACKGAPLEN + szsigcode + 345 sizeof(struct ps_strings)) - argp; 346 347 len = ALIGN(len); /* make the stack "safely" aligned */ 348 349 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 350 error = ENOMEM; 351 goto bad; 352 } 353 354 /* adjust "active stack depth" for process VSZ */ 355 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 356 357 /* 358 * Do whatever is necessary to prepare the address space 359 * for remapping. Note that this might replace the current 360 * vmspace with another! 361 */ 362 vmspace_exec(p); 363 364 /* Now map address space */ 365 vm = p->p_vmspace; 366 vm->vm_taddr = (char *) pack.ep_taddr; 367 vm->vm_tsize = btoc(pack.ep_tsize); 368 vm->vm_daddr = (char *) pack.ep_daddr; 369 vm->vm_dsize = btoc(pack.ep_dsize); 370 vm->vm_ssize = btoc(pack.ep_ssize); 371 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 372 373 /* create the new process's VM space by running the vmcmds */ 374 #ifdef DIAGNOSTIC 375 if (pack.ep_vmcmds.evs_used == 0) 376 panic("execve: no vmcmds"); 377 #endif 378 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 379 struct exec_vmcmd *vcp; 380 381 vcp = &pack.ep_vmcmds.evs_cmds[i]; 382 error = (*vcp->ev_proc)(p, vcp); 383 } 384 385 /* free the vmspace-creation commands, and release their references */ 386 kill_vmcmds(&pack.ep_vmcmds); 387 388 /* if an error happened, deallocate and punt */ 389 if (error) 390 goto exec_abort; 391 392 /* remember information about the process */ 393 arginfo.ps_nargvstr = argc; 394 arginfo.ps_nenvstr = envc; 395 396 stack = (char *) (USRSTACK - len); 397 /* Now copy argc, args & environ to new stack */ 398 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 399 goto exec_abort; 400 401 /* copy out the process's ps_strings structure */ 402 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 403 goto exec_abort; 404 405 /* copy out the process's signal trapoline code */ 406 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 407 ((char *) PS_STRINGS) - szsigcode, 408 szsigcode)) 409 goto exec_abort; 410 411 fdcloseexec(p); /* handle close on exec */ 412 execsigs(p); /* reset catched signals */ 413 414 /* set command name & other accounting info */ 415 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 416 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 417 p->p_comm[len] = 0; 418 p->p_acflag &= ~AFORK; 419 420 /* record proc's vnode, for use by procfs and others */ 421 if (p->p_textvp) 422 vrele(p->p_textvp); 423 VREF(pack.ep_vp); 424 p->p_textvp = pack.ep_vp; 425 426 p->p_flag |= P_EXEC; 427 if (p->p_flag & P_PPWAIT) { 428 p->p_flag &= ~P_PPWAIT; 429 wakeup((caddr_t) p->p_pptr); 430 } 431 432 /* 433 * deal with set[ug]id. 434 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 435 */ 436 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 437 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 438 p->p_ucred = crcopy(cred); 439 #ifdef KTRACE 440 /* 441 * If process is being ktraced, turn off - unless 442 * root set it. 443 */ 444 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 445 vrele(p->p_tracep); 446 p->p_tracep = NULL; 447 p->p_traceflag = 0; 448 } 449 #endif 450 if (attr.va_mode & S_ISUID) 451 p->p_ucred->cr_uid = attr.va_uid; 452 if (attr.va_mode & S_ISGID) 453 p->p_ucred->cr_gid = attr.va_gid; 454 p->p_flag |= P_SUGID; 455 } else 456 p->p_flag &= ~P_SUGID; 457 p->p_cred->p_svuid = p->p_ucred->cr_uid; 458 p->p_cred->p_svgid = p->p_ucred->cr_gid; 459 460 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 461 462 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 463 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 464 vrele(pack.ep_vp); 465 466 /* setup new registers and do misc. setup. */ 467 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 468 469 if (p->p_flag & P_TRACED) 470 psignal(p, SIGTRAP); 471 472 p->p_emul = pack.ep_emul; 473 FREE(pack.ep_hdr, M_EXEC); 474 475 #ifdef KTRACE 476 if (KTRPOINT(p, KTR_EMUL)) 477 ktremul(p->p_tracep, p->p_emul->e_name); 478 #endif 479 480 return (EJUSTRETURN); 481 482 bad: 483 /* free the vmspace-creation commands, and release their references */ 484 kill_vmcmds(&pack.ep_vmcmds); 485 /* kill any opened file descriptor, if necessary */ 486 if (pack.ep_flags & EXEC_HASFD) { 487 pack.ep_flags &= ~EXEC_HASFD; 488 (void) fdrelease(p, pack.ep_fd); 489 } 490 /* close and put the exec'd file */ 491 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 492 vrele(pack.ep_vp); 493 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 494 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 495 496 freehdr: 497 FREE(pack.ep_hdr, M_EXEC); 498 return error; 499 500 exec_abort: 501 /* 502 * the old process doesn't exist anymore. exit gracefully. 503 * get rid of the (new) address space we have created, if any, get rid 504 * of our namei data and vnode, and exit noting failure 505 */ 506 vm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 507 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 508 if (pack.ep_emul_arg) 509 FREE(pack.ep_emul_arg, M_TEMP); 510 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 511 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 512 vrele(pack.ep_vp); 513 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 514 FREE(pack.ep_hdr, M_EXEC); 515 exit1(p, W_EXITCODE(0, SIGABRT)); 516 exit1(p, -1); 517 518 /* NOTREACHED */ 519 return 0; 520 } 521 522 523 void * 524 copyargs(pack, arginfo, stack, argp) 525 struct exec_package *pack; 526 struct ps_strings *arginfo; 527 void *stack; 528 void *argp; 529 { 530 char **cpp = stack; 531 char *dp, *sp; 532 size_t len; 533 void *nullp = NULL; 534 int argc = arginfo->ps_nargvstr; 535 int envc = arginfo->ps_nenvstr; 536 537 if (copyout(&argc, cpp++, sizeof(argc))) 538 return NULL; 539 540 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 541 sp = argp; 542 543 /* XXX don't copy them out, remap them! */ 544 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 545 546 for (; --argc >= 0; sp += len, dp += len) 547 if (copyout(&dp, cpp++, sizeof(dp)) || 548 copyoutstr(sp, dp, ARG_MAX, &len)) 549 return NULL; 550 551 if (copyout(&nullp, cpp++, sizeof(nullp))) 552 return NULL; 553 554 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 555 556 for (; --envc >= 0; sp += len, dp += len) 557 if (copyout(&dp, cpp++, sizeof(dp)) || 558 copyoutstr(sp, dp, ARG_MAX, &len)) 559 return NULL; 560 561 if (copyout(&nullp, cpp++, sizeof(nullp))) 562 return NULL; 563 564 return cpp; 565 } 566