kern_exec.c revision 1.86
1 /* $NetBSD: kern_exec.c,v 1.86 1997/12/31 07:47:44 thorpej 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 #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 (unlocked). 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 (unlocked). 84 * error: destructive: 85 * everything deallocated execept exec header. 86 * non-destructive: 87 * error code, executable's vnode (unlocked), 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 access and type */ 109 if (vp->v_type != VREG) { 110 error = EACCES; 111 goto bad1; 112 } 113 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 114 goto bad1; 115 116 /* get attributes */ 117 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 118 goto bad1; 119 120 /* Check mount point */ 121 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 122 error = EACCES; 123 goto bad1; 124 } 125 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 126 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 127 128 /* try to open it */ 129 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 130 goto bad1; 131 132 /* unlock vp, since we don't need it locked from here on out. */ 133 VOP_UNLOCK(vp); 134 135 /* now we have the file, get the exec header */ 136 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 137 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 138 if (error) 139 goto bad2; 140 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 141 142 /* 143 * set up the vmcmds for creation of the process 144 * address space 145 */ 146 error = ENOEXEC; 147 for (i = 0; i < nexecs && error != 0; i++) { 148 int newerror; 149 150 if (execsw[i].es_check == NULL) 151 continue; 152 153 newerror = (*execsw[i].es_check)(p, epp); 154 /* make sure the first "interesting" error code is saved. */ 155 if (!newerror || error == ENOEXEC) 156 error = newerror; 157 if (epp->ep_flags & EXEC_DESTR && error != 0) 158 return error; 159 } 160 if (!error) { 161 /* check that entry point is sane */ 162 if (epp->ep_entry > VM_MAXUSER_ADDRESS) 163 error = ENOEXEC; 164 165 /* check limits */ 166 if ((epp->ep_tsize > MAXTSIZ) || 167 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 168 error = ENOMEM; 169 170 if (!error) 171 return (0); 172 } 173 174 /* 175 * free any vmspace-creation commands, 176 * and release their references 177 */ 178 kill_vmcmds(&epp->ep_vmcmds); 179 180 bad2: 181 /* 182 * unlock and close the vnode, restore the old one, free the 183 * pathname buf, and punt. 184 */ 185 VOP_CLOSE(vp, FREAD, p->p_ucred, p); 186 vrele(vp); 187 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 188 return error; 189 190 bad1: 191 /* 192 * free the namei pathname buffer, and put the vnode 193 * (which we don't yet have open). 194 */ 195 vput(vp); /* was still locked */ 196 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 197 return error; 198 } 199 200 /* 201 * exec system call 202 */ 203 /* ARGSUSED */ 204 int 205 sys_execve(p, v, retval) 206 register struct proc *p; 207 void *v; 208 register_t *retval; 209 { 210 register struct sys_execve_args /* { 211 syscallarg(const char *) path; 212 syscallarg(char * const *) argp; 213 syscallarg(char * const *) envp; 214 } */ *uap = v; 215 int error, i; 216 struct exec_package pack; 217 struct nameidata nid; 218 struct vattr attr; 219 struct ucred *cred = p->p_ucred; 220 char *argp; 221 char * const *cpp; 222 char *dp, *sp; 223 long argc, envc; 224 size_t len; 225 char *stack; 226 struct ps_strings arginfo; 227 struct vmspace *vm; 228 char **tmpfap; 229 int szsigcode; 230 extern struct emul emul_netbsd; 231 232 /* 233 * figure out the maximum size of an exec header, if necessary. 234 * XXX should be able to keep LKM code from modifying exec switch 235 * when we're still using it, but... 236 */ 237 if (exec_maxhdrsz == 0) { 238 for (i = 0; i < nexecs; i++) 239 if (execsw[i].es_check != NULL 240 && execsw[i].es_hdrsz > exec_maxhdrsz) 241 exec_maxhdrsz = execsw[i].es_hdrsz; 242 } 243 244 /* init the namei data to point the file user's program name */ 245 /* XXX cgd 960926: why do this here? most will be clobbered. */ 246 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 247 248 /* 249 * initialize the fields of the exec package. 250 */ 251 pack.ep_name = SCARG(uap, path); 252 MALLOC(pack.ep_hdr, void *, exec_maxhdrsz, M_EXEC, M_WAITOK); 253 pack.ep_hdrlen = exec_maxhdrsz; 254 pack.ep_hdrvalid = 0; 255 pack.ep_ndp = &nid; 256 pack.ep_emul_arg = NULL; 257 pack.ep_vmcmds.evs_cnt = 0; 258 pack.ep_vmcmds.evs_used = 0; 259 pack.ep_vap = &attr; 260 pack.ep_emul = &emul_netbsd; 261 pack.ep_flags = 0; 262 263 /* see if we can run it. */ 264 if ((error = check_exec(p, &pack)) != 0) 265 goto freehdr; 266 267 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 268 269 /* allocate an argument buffer */ 270 argp = (char *) kmem_alloc_wait(exec_map, NCARGS); 271 #ifdef DIAGNOSTIC 272 if (argp == (vm_offset_t) 0) 273 panic("execve: argp == NULL"); 274 #endif 275 dp = argp; 276 argc = 0; 277 278 /* copy the fake args list, if there's one, freeing it as we go */ 279 if (pack.ep_flags & EXEC_HASARGL) { 280 tmpfap = pack.ep_fa; 281 while (*tmpfap != NULL) { 282 char *cp; 283 284 cp = *tmpfap; 285 while (*cp) 286 *dp++ = *cp++; 287 dp++; 288 289 FREE(*tmpfap, M_EXEC); 290 tmpfap++; argc++; 291 } 292 FREE(pack.ep_fa, M_EXEC); 293 pack.ep_flags &= ~EXEC_HASARGL; 294 } 295 296 /* Now get argv & environment */ 297 if (!(cpp = SCARG(uap, argp))) { 298 error = EINVAL; 299 goto bad; 300 } 301 302 if (pack.ep_flags & EXEC_SKIPARG) 303 cpp++; 304 305 while (1) { 306 len = argp + ARG_MAX - dp; 307 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 308 goto bad; 309 if (!sp) 310 break; 311 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 312 if (error == ENAMETOOLONG) 313 error = E2BIG; 314 goto bad; 315 } 316 dp += len; 317 cpp++; 318 argc++; 319 } 320 321 envc = 0; 322 /* environment need not be there */ 323 if ((cpp = SCARG(uap, envp)) != NULL ) { 324 while (1) { 325 len = argp + ARG_MAX - dp; 326 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 327 goto bad; 328 if (!sp) 329 break; 330 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 331 if (error == ENAMETOOLONG) 332 error = E2BIG; 333 goto bad; 334 } 335 dp += len; 336 cpp++; 337 envc++; 338 } 339 } 340 341 dp = (char *) ALIGN(dp); 342 343 szsigcode = pack.ep_emul->e_esigcode - pack.ep_emul->e_sigcode; 344 345 /* Now check if args & environ fit into new stack */ 346 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 347 sizeof(long) + dp + STACKGAPLEN + szsigcode + 348 sizeof(struct ps_strings)) - argp; 349 350 len = ALIGN(len); /* make the stack "safely" aligned */ 351 352 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 353 error = ENOMEM; 354 goto bad; 355 } 356 357 /* adjust "active stack depth" for process VSZ */ 358 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 359 360 /* 361 * Do whatever is necessary to prepare the address space 362 * for remapping. Note that this might replace the current 363 * vmspace with another! 364 */ 365 vmspace_exec(p); 366 367 /* Now map address space */ 368 vm = p->p_vmspace; 369 vm->vm_taddr = (char *) pack.ep_taddr; 370 vm->vm_tsize = btoc(pack.ep_tsize); 371 vm->vm_daddr = (char *) pack.ep_daddr; 372 vm->vm_dsize = btoc(pack.ep_dsize); 373 vm->vm_ssize = btoc(pack.ep_ssize); 374 vm->vm_maxsaddr = (char *) pack.ep_maxsaddr; 375 376 /* create the new process's VM space by running the vmcmds */ 377 #ifdef DIAGNOSTIC 378 if (pack.ep_vmcmds.evs_used == 0) 379 panic("execve: no vmcmds"); 380 #endif 381 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 382 struct exec_vmcmd *vcp; 383 384 vcp = &pack.ep_vmcmds.evs_cmds[i]; 385 error = (*vcp->ev_proc)(p, vcp); 386 } 387 388 /* free the vmspace-creation commands, and release their references */ 389 kill_vmcmds(&pack.ep_vmcmds); 390 391 /* if an error happened, deallocate and punt */ 392 if (error) 393 goto exec_abort; 394 395 /* remember information about the process */ 396 arginfo.ps_nargvstr = argc; 397 arginfo.ps_nenvstr = envc; 398 399 stack = (char *) (USRSTACK - len); 400 /* Now copy argc, args & environ to new stack */ 401 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 402 goto exec_abort; 403 404 /* copy out the process's ps_strings structure */ 405 if (copyout(&arginfo, (char *) PS_STRINGS, sizeof(arginfo))) 406 goto exec_abort; 407 408 /* copy out the process's signal trapoline code */ 409 if (szsigcode && copyout((char *) pack.ep_emul->e_sigcode, 410 ((char *) PS_STRINGS) - szsigcode, 411 szsigcode)) 412 goto exec_abort; 413 414 fdcloseexec(p); /* handle close on exec */ 415 execsigs(p); /* reset catched signals */ 416 417 /* set command name & other accounting info */ 418 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 419 bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len); 420 p->p_comm[len] = 0; 421 p->p_acflag &= ~AFORK; 422 423 /* record proc's vnode, for use by procfs and others */ 424 if (p->p_textvp) 425 vrele(p->p_textvp); 426 VREF(pack.ep_vp); 427 p->p_textvp = pack.ep_vp; 428 429 p->p_flag |= P_EXEC; 430 if (p->p_flag & P_PPWAIT) { 431 p->p_flag &= ~P_PPWAIT; 432 wakeup((caddr_t) p->p_pptr); 433 } 434 435 /* 436 * deal with set[ug]id. 437 * MNT_NOEXEC and P_TRACED have already been used to disable s[ug]id. 438 */ 439 if (((attr.va_mode & S_ISUID) != 0 && p->p_ucred->cr_uid != attr.va_uid) 440 || ((attr.va_mode & S_ISGID) != 0 && p->p_ucred->cr_gid != attr.va_gid)){ 441 p->p_ucred = crcopy(cred); 442 #ifdef KTRACE 443 /* 444 * If process is being ktraced, turn off - unless 445 * root set it. 446 */ 447 if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { 448 vrele(p->p_tracep); 449 p->p_tracep = NULL; 450 p->p_traceflag = 0; 451 } 452 #endif 453 if (attr.va_mode & S_ISUID) 454 p->p_ucred->cr_uid = attr.va_uid; 455 if (attr.va_mode & S_ISGID) 456 p->p_ucred->cr_gid = attr.va_gid; 457 p->p_flag |= P_SUGID; 458 } else 459 p->p_flag &= ~P_SUGID; 460 p->p_cred->p_svuid = p->p_ucred->cr_uid; 461 p->p_cred->p_svgid = p->p_ucred->cr_gid; 462 463 kmem_free_wakeup(exec_map, (vm_offset_t) argp, NCARGS); 464 465 FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI); 466 VOP_CLOSE(pack.ep_vp, FREAD, cred, p); 467 vrele(pack.ep_vp); 468 469 /* setup new registers and do misc. setup. */ 470 (*pack.ep_emul->e_setregs)(p, &pack, (u_long) stack); 471 472 if (p->p_flag & P_TRACED) 473 psignal(p, SIGTRAP); 474 475 p->p_emul = pack.ep_emul; 476 FREE(pack.ep_hdr, M_EXEC); 477 478 #ifdef KTRACE 479 if (KTRPOINT(p, KTR_EMUL)) 480 ktremul(p->p_tracep, p->p_emul->e_name); 481 #endif 482 483 return (EJUSTRETURN); 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 vrele(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 vrele(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
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