exec_elf32.c revision 1.31
1/* $NetBSD: exec_elf32.c,v 1.31 1998/06/25 23:22:51 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 39#include <sys/param.h> 40#include <sys/systm.h> 41#include <sys/kernel.h> 42#include <sys/proc.h> 43#include <sys/malloc.h> 44#include <sys/namei.h> 45#include <sys/vnode.h> 46#include <sys/exec.h> 47#include <sys/exec_elf.h> 48#include <sys/fcntl.h> 49#include <sys/syscall.h> 50#include <sys/signalvar.h> 51#include <sys/mount.h> 52#include <sys/stat.h> 53 54#include <sys/mman.h> 55#include <vm/vm.h> 56#include <vm/vm_param.h> 57#include <vm/vm_map.h> 58 59#include <machine/cpu.h> 60#include <machine/reg.h> 61 62#ifdef COMPAT_LINUX 63#include <compat/linux/linux_exec.h> 64#endif 65 66#ifdef COMPAT_SVR4 67#include <compat/svr4/svr4_exec.h> 68#endif 69 70#ifdef COMPAT_IBCS2 71#include <compat/ibcs2/ibcs2_exec.h> 72#endif 73 74#define CONCAT(x,y) __CONCAT(x,y) 75#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 76#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 77#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 78#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 79 80int ELFNAME(check_header) __P((Elf_Ehdr *, int)); 81int ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *, 82 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *)); 83void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *, 84 Elf_Phdr *, Elf_Addr *, u_long *, int *)); 85 86extern char sigcode[], esigcode[]; 87#ifdef SYSCALL_DEBUG 88extern char *syscallnames[]; 89#endif 90 91struct emul ELFNAMEEND(emul_netbsd) = { 92 "netbsd", 93 NULL, 94 sendsig, 95 SYS_syscall, 96 SYS_MAXSYSCALL, 97 sysent, 98#ifdef SYSCALL_DEBUG 99 syscallnames, 100#else 101 NULL, 102#endif 103 ELF_AUX_ENTRIES * sizeof(AuxInfo), 104 ELFNAME(copyargs), 105 setregs, 106 sigcode, 107 esigcode, 108}; 109 110int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, 111 Elf_Ehdr *, char *, Elf_Addr *)) = { 112#if defined(COMPAT_LINUX) && (ELFSIZE == 32) 113 ELFNAME2(linux,probe), /* XXX not 64-bit safe */ 114#endif 115#if defined(COMPAT_SVR4) && (ELFSIZE == 32) 116 ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ 117#endif 118#if defined(COMPAT_IBCS2) && (ELFSIZE == 32) 119 ELFNAME2(ibcs2,probe), /* XXX not 64-bit safe */ 120#endif 121}; 122 123/* round up and down to page boundaries. */ 124#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 125#define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 126 127/* 128 * Copy arguments onto the stack in the normal way, but add some 129 * extra information in case of dynamic binding. 130 */ 131void * 132ELFNAME(copyargs)(pack, arginfo, stack, argp) 133 struct exec_package *pack; 134 struct ps_strings *arginfo; 135 void *stack; 136 void *argp; 137{ 138 size_t len; 139 AuxInfo ai[ELF_AUX_ENTRIES], *a; 140 struct elf_args *ap; 141 142 stack = copyargs(pack, arginfo, stack, argp); 143 if (!stack) 144 return NULL; 145 146 a = ai; 147 148 /* 149 * Push extra arguments on the stack needed by dynamically 150 * linked binaries 151 */ 152 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 153 154 a->au_id = AUX_phdr; 155 a->au_v = ap->arg_phaddr; 156 a++; 157 158 a->au_id = AUX_phent; 159 a->au_v = ap->arg_phentsize; 160 a++; 161 162 a->au_id = AUX_phnum; 163 a->au_v = ap->arg_phnum; 164 a++; 165 166 a->au_id = AUX_pagesz; 167 a->au_v = NBPG; 168 a++; 169 170 a->au_id = AUX_base; 171 a->au_v = ap->arg_interp; 172 a++; 173 174 a->au_id = AUX_flags; 175 a->au_v = 0; 176 a++; 177 178 a->au_id = AUX_entry; 179 a->au_v = ap->arg_entry; 180 a++; 181 182 free((char *)ap, M_TEMP); 183 pack->ep_emul_arg = NULL; 184 } 185 186 a->au_id = AUX_null; 187 a->au_v = 0; 188 a++; 189 190 len = (a - ai) * sizeof (AuxInfo); 191 if (copyout(ai, stack, len)) 192 return NULL; 193 (caddr_t)stack += len; 194 195 return stack; 196} 197 198/* 199 * elf_check_header(): 200 * 201 * Check header for validity; return 0 of ok ENOEXEC if error 202 */ 203int 204ELFNAME(check_header)(eh, type) 205 Elf_Ehdr *eh; 206 int type; 207{ 208 209 if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) 210 return ENOEXEC; 211 212 switch (eh->e_machine) { 213 214 ELFDEFNNAME(MACHDEP_ID_CASES) 215 216 default: 217 return ENOEXEC; 218 } 219 220 if (eh->e_type != type) 221 return ENOEXEC; 222 223 return 0; 224} 225 226/* 227 * elf_load_psection(): 228 * 229 * Load a psection at the appropriate address 230 */ 231void 232ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) 233 struct exec_vmcmd_set *vcset; 234 struct vnode *vp; 235 Elf_Phdr *ph; 236 Elf_Addr *addr; 237 u_long *size; 238 int *prot; 239{ 240 u_long uaddr, msize, psize, rm, rf; 241 long diff, offset; 242 243 /* 244 * If the user specified an address, then we load there. 245 */ 246 if (*addr != ELFDEFNNAME(NO_ADDR)) { 247 if (ph->p_align > 1) { 248 *addr = ELF_ROUND(*addr, ph->p_align); 249 uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align); 250 } else 251 uaddr = ph->p_vaddr; 252 diff = ph->p_vaddr - uaddr; 253 } else { 254 *addr = uaddr = ph->p_vaddr; 255 if (ph->p_align > 1) 256 *addr = ELF_TRUNC(uaddr, ph->p_align); 257 diff = uaddr - *addr; 258 } 259 260 *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; 261 *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; 262 *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; 263 264 offset = ph->p_offset - diff; 265 *size = ph->p_filesz + diff; 266 msize = ph->p_memsz + diff; 267 psize = round_page(*size); 268 269 if ((ph->p_flags & Elf_pf_w) != 0) { 270 /* 271 * Because the pagedvn pager can't handle zero fill of the last 272 * data page if it's not page aligned we map the last page 273 * readvn. 274 */ 275 psize = trunc_page(*size); 276 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 277 offset, *prot); 278 if(psize != *size) 279 NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, 280 *addr + psize, vp, offset + psize, *prot); 281 } else 282 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 283 offset, *prot); 284 285 /* 286 * Check if we need to extend the size of the segment 287 */ 288 rm = round_page(*addr + msize); 289 rf = round_page(*addr + *size); 290 291 if (rm != rf) { 292 NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 293 0, *prot); 294 *size = msize; 295 } 296} 297 298/* 299 * elf_read_from(): 300 * 301 * Read from vnode into buffer at offset. 302 */ 303int 304ELFNAME(read_from)(p, vp, off, buf, size) 305 struct vnode *vp; 306 u_long off; 307 struct proc *p; 308 caddr_t buf; 309 int size; 310{ 311 int error; 312 int resid; 313 314 if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE, 315 0, p->p_ucred, &resid, p)) != 0) 316 return error; 317 /* 318 * See if we got all of it 319 */ 320 if (resid != 0) 321 return ENOEXEC; 322 return 0; 323} 324 325/* 326 * elf_load_file(): 327 * 328 * Load a file (interpreter/library) pointed to by path 329 * [stolen from coff_load_shlib()]. Made slightly generic 330 * so it might be used externally. 331 */ 332int 333ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last) 334 struct proc *p; 335 struct exec_package *epp; 336 char *path; 337 struct exec_vmcmd_set *vcset; 338 u_long *entry; 339 struct elf_args *ap; 340 Elf_Addr *last; 341{ 342 int error, i; 343 struct nameidata nd; 344 struct vnode *vp; 345 struct vattr attr; 346 Elf_Ehdr eh; 347 Elf_Phdr *ph = NULL; 348 u_long phsize; 349 char *bp = NULL; 350 Elf_Addr addr = *last; 351 352 bp = path; 353 /* 354 * 1. open file 355 * 2. read filehdr 356 * 3. map text, data, and bss out of it using VM_* 357 */ 358 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); 359 if ((error = namei(&nd)) != 0) 360 return error; 361 vp = nd.ni_vp; 362 363 /* 364 * Similarly, if it's not marked as executable, or it's not a regular 365 * file, we don't allow it to be used. 366 */ 367 if (vp->v_type != VREG) { 368 error = EACCES; 369 goto badunlock; 370 } 371 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 372 goto badunlock; 373 374 /* get attributes */ 375 if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0) 376 goto badunlock; 377 378 /* 379 * Check mount point. Though we're not trying to exec this binary, 380 * we will be executing code from it, so if the mount point 381 * disallows execution or set-id-ness, we punt or kill the set-id. 382 */ 383 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 384 error = EACCES; 385 goto badunlock; 386 } 387 if (vp->v_mount->mnt_flag & MNT_NOSUID) 388 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 389 390#ifdef notyet /* XXX cgd 960926 */ 391 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 392#endif 393 VOP_UNLOCK(vp, 0); 394 395 if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh, 396 sizeof(eh))) != 0) 397 goto bad; 398 399 if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) 400 goto bad; 401 402 phsize = eh.e_phnum * sizeof(Elf_Phdr); 403 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 404 405 if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff, 406 (caddr_t) ph, phsize)) != 0) 407 goto bad; 408 409 /* 410 * Load all the necessary sections 411 */ 412 for (i = 0; i < eh.e_phnum; i++) { 413 u_long size = 0; 414 int prot = 0; 415 416 switch (ph[i].p_type) { 417 case Elf_pt_load: 418 ELFNAME(load_psection)(vcset, vp, &ph[i], &addr, 419 &size, &prot); 420 /* If entry is within this section it must be text */ 421 if (eh.e_entry >= ph[i].p_vaddr && 422 eh.e_entry < (ph[i].p_vaddr + size)) { 423 /* XXX */ 424 *entry = addr + eh.e_entry; 425#ifdef mips 426 *entry -= ph[i].p_vaddr; 427#endif 428 ap->arg_interp = addr; 429 } 430 addr += size; 431 break; 432 433 case Elf_pt_dynamic: 434 case Elf_pt_phdr: 435 case Elf_pt_note: 436 break; 437 438 default: 439 break; 440 } 441 } 442 443 free((char *)ph, M_TEMP); 444 *last = addr; 445 vrele(vp); 446 return 0; 447 448badunlock: 449 VOP_UNLOCK(vp, 0); 450 451bad: 452 if (ph != NULL) 453 free((char *)ph, M_TEMP); 454#ifdef notyet /* XXX cgd 960926 */ 455 (maybe) VOP_CLOSE it 456#endif 457 vrele(vp); 458 return error; 459} 460 461/* 462 * exec_elf_makecmds(): Prepare an Elf binary's exec package 463 * 464 * First, set of the various offsets/lengths in the exec package. 465 * 466 * Then, mark the text image busy (so it can be demand paged) or error 467 * out if this is not possible. Finally, set up vmcmds for the 468 * text, data, bss, and stack segments. 469 */ 470int 471ELFNAME2(exec,makecmds)(p, epp) 472 struct proc *p; 473 struct exec_package *epp; 474{ 475 Elf_Ehdr *eh = epp->ep_hdr; 476 Elf_Phdr *ph, *pp; 477 Elf_Addr phdr = 0, pos = 0; 478 int error, i, n, nload; 479 char interp[MAXPATHLEN]; 480 u_long phsize; 481 482 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 483 return ENOEXEC; 484 485 if (ELFNAME(check_header)(eh, Elf_et_exec)) 486 return ENOEXEC; 487 488 /* 489 * check if vnode is in open for writing, because we want to 490 * demand-page out of it. if it is, don't do it, for various 491 * reasons 492 */ 493 if (epp->ep_vp->v_writecount != 0) { 494#ifdef DIAGNOSTIC 495 if (epp->ep_vp->v_flag & VTEXT) 496 panic("exec: a VTEXT vnode has writecount != 0\n"); 497#endif 498 return ETXTBSY; 499 } 500 /* 501 * Allocate space to hold all the program headers, and read them 502 * from the file 503 */ 504 phsize = eh->e_phnum * sizeof(Elf_Phdr); 505 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 506 507 if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, 508 (caddr_t) ph, phsize)) != 0) 509 goto bad; 510 511 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 512 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 513 514 interp[0] = '\0'; 515 516 for (i = 0; i < eh->e_phnum; i++) { 517 pp = &ph[i]; 518 if (pp->p_type == Elf_pt_interp) { 519 if (pp->p_filesz >= sizeof(interp)) 520 goto bad; 521 if ((error = ELFNAME(read_from)(p, epp->ep_vp, 522 pp->p_offset, (caddr_t) interp, 523 pp->p_filesz)) != 0) 524 goto bad; 525 break; 526 } 527 } 528 529 /* 530 * Setup things for native emulation. 531 */ 532 epp->ep_emul = &ELFNAMEEND(emul_netbsd); 533 pos = ELFDEFNNAME(NO_ADDR); 534 535 /* 536 * On the same architecture, we may be emulating different systems. 537 * See which one will accept this executable. This currently only 538 * applies to Linux, SVR4, and IBCS2 on the i386. 539 * 540 * Probe functions would normally see if the interpreter (if any) 541 * exists. Emulation packages may possibly replace the interpreter in 542 * interp[] with a changed path (/emul/xxx/<path>), and also 543 * set the ep_emul field in the exec package structure. 544 */ 545 n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0]; 546 if (n != 0) { 547 error = ENOEXEC; 548 for (i = 0; i < n && error; i++) 549 error = ELFNAME(probe_funcs)[i](p, epp, eh, 550 interp, &pos); 551 552#ifdef notyet 553 /* 554 * We should really use a signature in our native binaries 555 * and have our own probe function for matching binaries, 556 * before trying the emulations. For now, if the emulation 557 * probes failed we default to native. 558 */ 559 if (error) 560 goto bad; 561#endif 562 } 563 564 /* 565 * Load all the necessary sections 566 */ 567 for (i = nload = 0; i < eh->e_phnum; i++) { 568 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 569 u_long size = 0; 570 int prot = 0; 571 572 pp = &ph[i]; 573 574 switch (ph[i].p_type) { 575 case Elf_pt_load: 576 /* 577 * XXX 578 * Can handle only 2 sections: text and data 579 */ 580 if (nload++ == 2) 581 goto bad; 582 ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, 583 &ph[i], &addr, &size, &prot); 584 585 /* 586 * Decide whether it's text or data by looking 587 * at the entry point. 588 */ 589 if (eh->e_entry >= addr && 590 eh->e_entry < (addr + size)) { 591 epp->ep_taddr = addr; 592 epp->ep_tsize = size; 593 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 594 epp->ep_daddr = addr; 595 epp->ep_dsize = size; 596 } 597 } else { 598 epp->ep_daddr = addr; 599 epp->ep_dsize = size; 600 } 601 break; 602 603 case Elf_pt_shlib: 604#ifndef COMPAT_IBCS2 /* SCO has these sections */ 605 error = ENOEXEC; 606 goto bad; 607#endif 608 609 case Elf_pt_interp: 610 /* Already did this one */ 611 case Elf_pt_dynamic: 612 case Elf_pt_note: 613 break; 614 615 case Elf_pt_phdr: 616 /* Note address of program headers (in text segment) */ 617 phdr = pp->p_vaddr; 618 break; 619 620 default: 621 /* 622 * Not fatal; we don't need to understand everything. 623 */ 624 break; 625 } 626 } 627 628 /* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */ 629#ifndef ELF_INTERP_NON_RELOCATABLE 630 /* 631 * If no position to load the interpreter was set by a probe 632 * function, pick the same address that a non-fixed mmap(0, ..) 633 * would (i.e. something safely out of the way). 634 */ 635 if (pos == ELFDEFNNAME(NO_ADDR)) 636 pos = round_page(epp->ep_daddr + MAXDSIZ); 637#endif /* !ELF_INTERP_NON_RELOCATABLE */ 638 639 /* 640 * Check if we found a dynamically linked binary and arrange to load 641 * it's interpreter 642 */ 643 if (interp[0]) { 644 struct elf_args *ap; 645 646 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 647 M_TEMP, M_WAITOK); 648 if ((error = ELFNAME(load_file)(p, epp, interp, 649 &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) { 650 free((char *)ap, M_TEMP); 651 goto bad; 652 } 653 pos += phsize; 654 ap->arg_phaddr = phdr; 655 656 ap->arg_phentsize = eh->e_phentsize; 657 ap->arg_phnum = eh->e_phnum; 658 ap->arg_entry = eh->e_entry; 659 660 epp->ep_emul_arg = ap; 661 } else 662 epp->ep_entry = eh->e_entry; 663 664#ifdef ELF_MAP_PAGE_ZERO 665 /* Dell SVR4 maps page zero, yeuch! */ 666 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, 667 VM_PROT_READ); 668#endif 669 free((char *)ph, M_TEMP); 670 epp->ep_vp->v_flag |= VTEXT; 671 return exec_elf_setup_stack(p, epp); 672 673bad: 674 free((char *)ph, M_TEMP); 675 kill_vmcmds(&epp->ep_vmcmds); 676 return ENOEXEC; 677} 678