exec_elf32.c revision 1.32
1/* $NetBSD: exec_elf32.c,v 1.32 1998/06/26 00:07:45 thorpej Exp $ */ 2 3/* 4 * Copyright (c) 1996 Christopher G. Demetriou 5 * Copyright (c) 1994 Christos Zoulas 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31/* If not included by exec_elf64.c, ELFSIZE won't be defined. */ 32#ifndef ELFSIZE 33#define ELFSIZE 32 34#endif 35 36#include "opt_compat_linux.h" 37#include "opt_compat_ibcs2.h" 38#include "opt_compat_svr4.h" 39 40#include <sys/param.h> 41#include <sys/systm.h> 42#include <sys/kernel.h> 43#include <sys/proc.h> 44#include <sys/malloc.h> 45#include <sys/namei.h> 46#include <sys/vnode.h> 47#include <sys/exec.h> 48#include <sys/exec_elf.h> 49#include <sys/fcntl.h> 50#include <sys/syscall.h> 51#include <sys/signalvar.h> 52#include <sys/mount.h> 53#include <sys/stat.h> 54 55#include <sys/mman.h> 56#include <vm/vm.h> 57#include <vm/vm_param.h> 58#include <vm/vm_map.h> 59 60#include <machine/cpu.h> 61#include <machine/reg.h> 62 63#ifdef COMPAT_LINUX 64#include <compat/linux/linux_exec.h> 65#endif 66 67#ifdef COMPAT_SVR4 68#include <compat/svr4/svr4_exec.h> 69#endif 70 71#ifdef COMPAT_IBCS2 72#include <compat/ibcs2/ibcs2_exec.h> 73#endif 74 75#define CONCAT(x,y) __CONCAT(x,y) 76#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 77#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 78#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 79#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 80 81int ELFNAME(check_header) __P((Elf_Ehdr *, int)); 82int ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *, 83 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *)); 84void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *, 85 Elf_Phdr *, Elf_Addr *, u_long *, int *)); 86 87extern char sigcode[], esigcode[]; 88#ifdef SYSCALL_DEBUG 89extern char *syscallnames[]; 90#endif 91 92struct emul ELFNAMEEND(emul_netbsd) = { 93 "netbsd", 94 NULL, 95 sendsig, 96 SYS_syscall, 97 SYS_MAXSYSCALL, 98 sysent, 99#ifdef SYSCALL_DEBUG 100 syscallnames, 101#else 102 NULL, 103#endif 104 ELF_AUX_ENTRIES * sizeof(AuxInfo), 105 ELFNAME(copyargs), 106 setregs, 107 sigcode, 108 esigcode, 109}; 110 111int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, 112 Elf_Ehdr *, char *, Elf_Addr *)) = { 113#if defined(COMPAT_LINUX) && (ELFSIZE == 32) 114 ELFNAME2(linux,probe), /* XXX not 64-bit safe */ 115#endif 116#if defined(COMPAT_SVR4) && (ELFSIZE == 32) 117 ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ 118#endif 119#if defined(COMPAT_IBCS2) && (ELFSIZE == 32) 120 ELFNAME2(ibcs2,probe), /* XXX not 64-bit safe */ 121#endif 122}; 123 124/* round up and down to page boundaries. */ 125#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 126#define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 127 128/* 129 * Copy arguments onto the stack in the normal way, but add some 130 * extra information in case of dynamic binding. 131 */ 132void * 133ELFNAME(copyargs)(pack, arginfo, stack, argp) 134 struct exec_package *pack; 135 struct ps_strings *arginfo; 136 void *stack; 137 void *argp; 138{ 139 size_t len; 140 AuxInfo ai[ELF_AUX_ENTRIES], *a; 141 struct elf_args *ap; 142 143 stack = copyargs(pack, arginfo, stack, argp); 144 if (!stack) 145 return NULL; 146 147 a = ai; 148 149 /* 150 * Push extra arguments on the stack needed by dynamically 151 * linked binaries 152 */ 153 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 154 155 a->au_id = AUX_phdr; 156 a->au_v = ap->arg_phaddr; 157 a++; 158 159 a->au_id = AUX_phent; 160 a->au_v = ap->arg_phentsize; 161 a++; 162 163 a->au_id = AUX_phnum; 164 a->au_v = ap->arg_phnum; 165 a++; 166 167 a->au_id = AUX_pagesz; 168 a->au_v = NBPG; 169 a++; 170 171 a->au_id = AUX_base; 172 a->au_v = ap->arg_interp; 173 a++; 174 175 a->au_id = AUX_flags; 176 a->au_v = 0; 177 a++; 178 179 a->au_id = AUX_entry; 180 a->au_v = ap->arg_entry; 181 a++; 182 183 free((char *)ap, M_TEMP); 184 pack->ep_emul_arg = NULL; 185 } 186 187 a->au_id = AUX_null; 188 a->au_v = 0; 189 a++; 190 191 len = (a - ai) * sizeof (AuxInfo); 192 if (copyout(ai, stack, len)) 193 return NULL; 194 (caddr_t)stack += len; 195 196 return stack; 197} 198 199/* 200 * elf_check_header(): 201 * 202 * Check header for validity; return 0 of ok ENOEXEC if error 203 */ 204int 205ELFNAME(check_header)(eh, type) 206 Elf_Ehdr *eh; 207 int type; 208{ 209 210 if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) 211 return ENOEXEC; 212 213 switch (eh->e_machine) { 214 215 ELFDEFNNAME(MACHDEP_ID_CASES) 216 217 default: 218 return ENOEXEC; 219 } 220 221 if (eh->e_type != type) 222 return ENOEXEC; 223 224 return 0; 225} 226 227/* 228 * elf_load_psection(): 229 * 230 * Load a psection at the appropriate address 231 */ 232void 233ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) 234 struct exec_vmcmd_set *vcset; 235 struct vnode *vp; 236 Elf_Phdr *ph; 237 Elf_Addr *addr; 238 u_long *size; 239 int *prot; 240{ 241 u_long uaddr, msize, psize, rm, rf; 242 long diff, offset; 243 244 /* 245 * If the user specified an address, then we load there. 246 */ 247 if (*addr != ELFDEFNNAME(NO_ADDR)) { 248 if (ph->p_align > 1) { 249 *addr = ELF_ROUND(*addr, ph->p_align); 250 uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align); 251 } else 252 uaddr = ph->p_vaddr; 253 diff = ph->p_vaddr - uaddr; 254 } else { 255 *addr = uaddr = ph->p_vaddr; 256 if (ph->p_align > 1) 257 *addr = ELF_TRUNC(uaddr, ph->p_align); 258 diff = uaddr - *addr; 259 } 260 261 *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; 262 *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; 263 *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; 264 265 offset = ph->p_offset - diff; 266 *size = ph->p_filesz + diff; 267 msize = ph->p_memsz + diff; 268 psize = round_page(*size); 269 270 if ((ph->p_flags & Elf_pf_w) != 0) { 271 /* 272 * Because the pagedvn pager can't handle zero fill of the last 273 * data page if it's not page aligned we map the last page 274 * readvn. 275 */ 276 psize = trunc_page(*size); 277 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 278 offset, *prot); 279 if(psize != *size) 280 NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, 281 *addr + psize, vp, offset + psize, *prot); 282 } else 283 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 284 offset, *prot); 285 286 /* 287 * Check if we need to extend the size of the segment 288 */ 289 rm = round_page(*addr + msize); 290 rf = round_page(*addr + *size); 291 292 if (rm != rf) { 293 NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 294 0, *prot); 295 *size = msize; 296 } 297} 298 299/* 300 * elf_read_from(): 301 * 302 * Read from vnode into buffer at offset. 303 */ 304int 305ELFNAME(read_from)(p, vp, off, buf, size) 306 struct vnode *vp; 307 u_long off; 308 struct proc *p; 309 caddr_t buf; 310 int size; 311{ 312 int error; 313 int resid; 314 315 if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE, 316 0, p->p_ucred, &resid, p)) != 0) 317 return error; 318 /* 319 * See if we got all of it 320 */ 321 if (resid != 0) 322 return ENOEXEC; 323 return 0; 324} 325 326/* 327 * elf_load_file(): 328 * 329 * Load a file (interpreter/library) pointed to by path 330 * [stolen from coff_load_shlib()]. Made slightly generic 331 * so it might be used externally. 332 */ 333int 334ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last) 335 struct proc *p; 336 struct exec_package *epp; 337 char *path; 338 struct exec_vmcmd_set *vcset; 339 u_long *entry; 340 struct elf_args *ap; 341 Elf_Addr *last; 342{ 343 int error, i; 344 struct nameidata nd; 345 struct vnode *vp; 346 struct vattr attr; 347 Elf_Ehdr eh; 348 Elf_Phdr *ph = NULL; 349 u_long phsize; 350 char *bp = NULL; 351 Elf_Addr addr = *last; 352 353 bp = path; 354 /* 355 * 1. open file 356 * 2. read filehdr 357 * 3. map text, data, and bss out of it using VM_* 358 */ 359 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); 360 if ((error = namei(&nd)) != 0) 361 return error; 362 vp = nd.ni_vp; 363 364 /* 365 * Similarly, if it's not marked as executable, or it's not a regular 366 * file, we don't allow it to be used. 367 */ 368 if (vp->v_type != VREG) { 369 error = EACCES; 370 goto badunlock; 371 } 372 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 373 goto badunlock; 374 375 /* get attributes */ 376 if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0) 377 goto badunlock; 378 379 /* 380 * Check mount point. Though we're not trying to exec this binary, 381 * we will be executing code from it, so if the mount point 382 * disallows execution or set-id-ness, we punt or kill the set-id. 383 */ 384 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 385 error = EACCES; 386 goto badunlock; 387 } 388 if (vp->v_mount->mnt_flag & MNT_NOSUID) 389 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 390 391#ifdef notyet /* XXX cgd 960926 */ 392 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 393#endif 394 VOP_UNLOCK(vp, 0); 395 396 if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh, 397 sizeof(eh))) != 0) 398 goto bad; 399 400 if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) 401 goto bad; 402 403 phsize = eh.e_phnum * sizeof(Elf_Phdr); 404 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 405 406 if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff, 407 (caddr_t) ph, phsize)) != 0) 408 goto bad; 409 410 /* 411 * Load all the necessary sections 412 */ 413 for (i = 0; i < eh.e_phnum; i++) { 414 u_long size = 0; 415 int prot = 0; 416 417 switch (ph[i].p_type) { 418 case Elf_pt_load: 419 ELFNAME(load_psection)(vcset, vp, &ph[i], &addr, 420 &size, &prot); 421 /* If entry is within this section it must be text */ 422 if (eh.e_entry >= ph[i].p_vaddr && 423 eh.e_entry < (ph[i].p_vaddr + size)) { 424 /* XXX */ 425 *entry = addr + eh.e_entry; 426#ifdef mips 427 *entry -= ph[i].p_vaddr; 428#endif 429 ap->arg_interp = addr; 430 } 431 addr += size; 432 break; 433 434 case Elf_pt_dynamic: 435 case Elf_pt_phdr: 436 case Elf_pt_note: 437 break; 438 439 default: 440 break; 441 } 442 } 443 444 free((char *)ph, M_TEMP); 445 *last = addr; 446 vrele(vp); 447 return 0; 448 449badunlock: 450 VOP_UNLOCK(vp, 0); 451 452bad: 453 if (ph != NULL) 454 free((char *)ph, M_TEMP); 455#ifdef notyet /* XXX cgd 960926 */ 456 (maybe) VOP_CLOSE it 457#endif 458 vrele(vp); 459 return error; 460} 461 462/* 463 * exec_elf_makecmds(): Prepare an Elf binary's exec package 464 * 465 * First, set of the various offsets/lengths in the exec package. 466 * 467 * Then, mark the text image busy (so it can be demand paged) or error 468 * out if this is not possible. Finally, set up vmcmds for the 469 * text, data, bss, and stack segments. 470 */ 471int 472ELFNAME2(exec,makecmds)(p, epp) 473 struct proc *p; 474 struct exec_package *epp; 475{ 476 Elf_Ehdr *eh = epp->ep_hdr; 477 Elf_Phdr *ph, *pp; 478 Elf_Addr phdr = 0, pos = 0; 479 int error, i, n, nload; 480 char interp[MAXPATHLEN]; 481 u_long phsize; 482 483 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 484 return ENOEXEC; 485 486 if (ELFNAME(check_header)(eh, Elf_et_exec)) 487 return ENOEXEC; 488 489 /* 490 * check if vnode is in open for writing, because we want to 491 * demand-page out of it. if it is, don't do it, for various 492 * reasons 493 */ 494 if (epp->ep_vp->v_writecount != 0) { 495#ifdef DIAGNOSTIC 496 if (epp->ep_vp->v_flag & VTEXT) 497 panic("exec: a VTEXT vnode has writecount != 0\n"); 498#endif 499 return ETXTBSY; 500 } 501 /* 502 * Allocate space to hold all the program headers, and read them 503 * from the file 504 */ 505 phsize = eh->e_phnum * sizeof(Elf_Phdr); 506 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 507 508 if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, 509 (caddr_t) ph, phsize)) != 0) 510 goto bad; 511 512 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 513 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 514 515 interp[0] = '\0'; 516 517 for (i = 0; i < eh->e_phnum; i++) { 518 pp = &ph[i]; 519 if (pp->p_type == Elf_pt_interp) { 520 if (pp->p_filesz >= sizeof(interp)) 521 goto bad; 522 if ((error = ELFNAME(read_from)(p, epp->ep_vp, 523 pp->p_offset, (caddr_t) interp, 524 pp->p_filesz)) != 0) 525 goto bad; 526 break; 527 } 528 } 529 530 /* 531 * Setup things for native emulation. 532 */ 533 epp->ep_emul = &ELFNAMEEND(emul_netbsd); 534 pos = ELFDEFNNAME(NO_ADDR); 535 536 /* 537 * On the same architecture, we may be emulating different systems. 538 * See which one will accept this executable. This currently only 539 * applies to Linux, SVR4, and IBCS2 on the i386. 540 * 541 * Probe functions would normally see if the interpreter (if any) 542 * exists. Emulation packages may possibly replace the interpreter in 543 * interp[] with a changed path (/emul/xxx/<path>), and also 544 * set the ep_emul field in the exec package structure. 545 */ 546 n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0]; 547 if (n != 0) { 548 error = ENOEXEC; 549 for (i = 0; i < n && error; i++) 550 error = ELFNAME(probe_funcs)[i](p, epp, eh, 551 interp, &pos); 552 553#ifdef notyet 554 /* 555 * We should really use a signature in our native binaries 556 * and have our own probe function for matching binaries, 557 * before trying the emulations. For now, if the emulation 558 * probes failed we default to native. 559 */ 560 if (error) 561 goto bad; 562#endif 563 } 564 565 /* 566 * Load all the necessary sections 567 */ 568 for (i = nload = 0; i < eh->e_phnum; i++) { 569 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 570 u_long size = 0; 571 int prot = 0; 572 573 pp = &ph[i]; 574 575 switch (ph[i].p_type) { 576 case Elf_pt_load: 577 /* 578 * XXX 579 * Can handle only 2 sections: text and data 580 */ 581 if (nload++ == 2) 582 goto bad; 583 ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, 584 &ph[i], &addr, &size, &prot); 585 586 /* 587 * Decide whether it's text or data by looking 588 * at the entry point. 589 */ 590 if (eh->e_entry >= addr && 591 eh->e_entry < (addr + size)) { 592 epp->ep_taddr = addr; 593 epp->ep_tsize = size; 594 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 595 epp->ep_daddr = addr; 596 epp->ep_dsize = size; 597 } 598 } else { 599 epp->ep_daddr = addr; 600 epp->ep_dsize = size; 601 } 602 break; 603 604 case Elf_pt_shlib: 605#ifndef COMPAT_IBCS2 /* SCO has these sections */ 606 error = ENOEXEC; 607 goto bad; 608#endif 609 610 case Elf_pt_interp: 611 /* Already did this one */ 612 case Elf_pt_dynamic: 613 case Elf_pt_note: 614 break; 615 616 case Elf_pt_phdr: 617 /* Note address of program headers (in text segment) */ 618 phdr = pp->p_vaddr; 619 break; 620 621 default: 622 /* 623 * Not fatal; we don't need to understand everything. 624 */ 625 break; 626 } 627 } 628 629 /* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */ 630#ifndef ELF_INTERP_NON_RELOCATABLE 631 /* 632 * If no position to load the interpreter was set by a probe 633 * function, pick the same address that a non-fixed mmap(0, ..) 634 * would (i.e. something safely out of the way). 635 */ 636 if (pos == ELFDEFNNAME(NO_ADDR)) 637 pos = round_page(epp->ep_daddr + MAXDSIZ); 638#endif /* !ELF_INTERP_NON_RELOCATABLE */ 639 640 /* 641 * Check if we found a dynamically linked binary and arrange to load 642 * it's interpreter 643 */ 644 if (interp[0]) { 645 struct elf_args *ap; 646 647 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 648 M_TEMP, M_WAITOK); 649 if ((error = ELFNAME(load_file)(p, epp, interp, 650 &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) { 651 free((char *)ap, M_TEMP); 652 goto bad; 653 } 654 pos += phsize; 655 ap->arg_phaddr = phdr; 656 657 ap->arg_phentsize = eh->e_phentsize; 658 ap->arg_phnum = eh->e_phnum; 659 ap->arg_entry = eh->e_entry; 660 661 epp->ep_emul_arg = ap; 662 } else 663 epp->ep_entry = eh->e_entry; 664 665#ifdef ELF_MAP_PAGE_ZERO 666 /* Dell SVR4 maps page zero, yeuch! */ 667 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, 668 VM_PROT_READ); 669#endif 670 free((char *)ph, M_TEMP); 671 epp->ep_vp->v_flag |= VTEXT; 672 return exec_elf_setup_stack(p, epp); 673 674bad: 675 free((char *)ph, M_TEMP); 676 kill_vmcmds(&epp->ep_vmcmds); 677 return ENOEXEC; 678} 679