exec_elf32.c revision 1.17
1/* $NetBSD: exec_elf32.c,v 1.17 1996/10/08 03:40:40 cgd 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 <sys/param.h> 37#include <sys/systm.h> 38#include <sys/kernel.h> 39#include <sys/proc.h> 40#include <sys/malloc.h> 41#include <sys/namei.h> 42#include <sys/vnode.h> 43#include <sys/exec.h> 44#include <sys/exec_elf.h> 45#include <sys/fcntl.h> 46#include <sys/syscall.h> 47#include <sys/signalvar.h> 48#include <sys/mount.h> 49#include <sys/stat.h> 50 51#include <sys/mman.h> 52#include <vm/vm.h> 53#include <vm/vm_param.h> 54#include <vm/vm_map.h> 55 56#include <machine/cpu.h> 57#include <machine/reg.h> 58 59#ifdef COMPAT_LINUX 60#include <compat/linux/linux_exec.h> 61#endif 62 63#ifdef COMPAT_SVR4 64#include <compat/svr4/svr4_exec.h> 65#endif 66 67#define CONCAT(x,y) __CONCAT(x,y) 68#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 69#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 70#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 71#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 72 73int ELFNAME(check_header) __P((Elf_Ehdr *, int)); 74int ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *, 75 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *)); 76void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *, 77 Elf_Phdr *, Elf_Addr *, u_long *, int *)); 78 79extern char sigcode[], esigcode[]; 80#ifdef SYSCALL_DEBUG 81extern char *syscallnames[]; 82#endif 83 84struct emul ELFNAMEEND(emul_netbsd) = { 85 "netbsd", 86 NULL, 87 sendsig, 88 SYS_syscall, 89 SYS_MAXSYSCALL, 90 sysent, 91#ifdef SYSCALL_DEBUG 92 syscallnames, 93#else 94 NULL, 95#endif 96 ELF_AUX_ENTRIES * sizeof(AuxInfo), 97 ELFNAME(copyargs), 98 setregs, 99 sigcode, 100 esigcode, 101}; 102 103int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, 104 Elf_Ehdr *, char *, Elf_Addr *)) = { 105#if defined(COMPAT_SVR4) && (ELFSIZE == 32) 106 ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ 107#endif 108#if defined(COMPAT_LINUX) && (ELFSIZE == 32) 109 ELFNAME2(linux,probe), /* XXX not 64-bit safe */ 110#endif 111}; 112 113#define ELF_ALIGN(a, b) ((a) & ~((b) - 1)) 114 115/* 116 * Copy arguments onto the stack in the normal way, but add some 117 * extra information in case of dynamic binding. 118 */ 119void * 120ELFNAME(copyargs)(pack, arginfo, stack, argp) 121 struct exec_package *pack; 122 struct ps_strings *arginfo; 123 void *stack; 124 void *argp; 125{ 126 size_t len; 127 AuxInfo ai[ELF_AUX_ENTRIES], *a; 128 struct elf_args *ap; 129 130 stack = copyargs(pack, arginfo, stack, argp); 131 if (!stack) 132 return NULL; 133 134 /* 135 * Push extra arguments on the stack needed by dynamically 136 * linked binaries 137 */ 138 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 139 a = ai; 140 141 a->au_id = AUX_phdr; 142 a->au_v = ap->arg_phaddr; 143 a++; 144 145 a->au_id = AUX_phent; 146 a->au_v = ap->arg_phentsize; 147 a++; 148 149 a->au_id = AUX_phnum; 150 a->au_v = ap->arg_phnum; 151 a++; 152 153 a->au_id = AUX_pagesz; 154 a->au_v = NBPG; 155 a++; 156 157 a->au_id = AUX_base; 158 a->au_v = ap->arg_interp; 159 a++; 160 161 a->au_id = AUX_flags; 162 a->au_v = 0; 163 a++; 164 165 a->au_id = AUX_entry; 166 a->au_v = ap->arg_entry; 167 a++; 168 169 a->au_id = AUX_null; 170 a->au_v = 0; 171 a++; 172 173 free((char *)ap, M_TEMP); 174 pack->ep_emul_arg = NULL; 175 len = ELF_AUX_ENTRIES * sizeof (AuxInfo); 176 if (copyout(ai, stack, len)) 177 return NULL; 178 stack += len; 179 } 180 return stack; 181} 182 183/* 184 * elf_check_header(): 185 * 186 * Check header for validity; return 0 of ok ENOEXEC if error 187 */ 188int 189ELFNAME(check_header)(eh, type) 190 Elf_Ehdr *eh; 191 int type; 192{ 193 194 if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) 195 return ENOEXEC; 196 197 switch (eh->e_machine) { 198 199 ELFDEFNNAME(MACHDEP_ID_CASES) 200 201 default: 202 return ENOEXEC; 203 } 204 205 if (eh->e_type != type) 206 return ENOEXEC; 207 208 return 0; 209} 210 211/* 212 * elf_load_psection(): 213 * 214 * Load a psection at the appropriate address 215 */ 216void 217ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) 218 struct exec_vmcmd_set *vcset; 219 struct vnode *vp; 220 Elf_Phdr *ph; 221 Elf_Addr *addr; 222 u_long *size; 223 int *prot; 224{ 225 u_long uaddr, msize, psize, rm, rf; 226 long diff, offset; 227 228 /* 229 * If the user specified an address, then we load there. 230 */ 231 if (*addr != ELFDEFNNAME(NO_ADDR)) { 232 if (ph->p_align > 1) { 233 *addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align); 234 uaddr = ELF_ALIGN(ph->p_vaddr, ph->p_align); 235 } else 236 uaddr = ph->p_vaddr; 237 diff = ph->p_vaddr - uaddr; 238 } else { 239 *addr = uaddr = ph->p_vaddr; 240 if (ph->p_align > 1) 241 *addr = ELF_ALIGN(uaddr, ph->p_align); 242 diff = uaddr - *addr; 243 } 244 245 *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; 246 *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; 247 *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; 248 249 offset = ph->p_offset - diff; 250 *size = ph->p_filesz + diff; 251 msize = ph->p_memsz + diff; 252 psize = round_page(*size); 253 254 if ((ph->p_flags & Elf_pf_w) != 0) { 255 /* 256 * Because the pagedvn pager can't handle zero fill of the last 257 * data page if it's not page aligned we map the last page 258 * readvn. 259 */ 260 psize = trunc_page(*size); 261 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 262 offset, *prot); 263 if(psize != *size) 264 NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, 265 *addr + psize, vp, offset + psize, *prot); 266 } else 267 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 268 offset, *prot); 269 270 /* 271 * Check if we need to extend the size of the segment 272 */ 273 rm = round_page(*addr + msize); 274 rf = round_page(*addr + *size); 275 276 if (rm != rf) { 277 NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 278 0, *prot); 279 *size = msize; 280 } 281} 282 283/* 284 * elf_read_from(): 285 * 286 * Read from vnode into buffer at offset. 287 */ 288int 289ELFNAME(read_from)(p, vp, off, buf, size) 290 struct vnode *vp; 291 u_long off; 292 struct proc *p; 293 caddr_t buf; 294 int size; 295{ 296 int error; 297 int resid; 298 299 if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE, 300 0, p->p_ucred, &resid, p)) != 0) 301 return error; 302 /* 303 * See if we got all of it 304 */ 305 if (resid != 0) 306 return ENOEXEC; 307 return 0; 308} 309 310/* 311 * elf_load_file(): 312 * 313 * Load a file (interpreter/library) pointed to by path 314 * [stolen from coff_load_shlib()]. Made slightly generic 315 * so it might be used externally. 316 */ 317int 318ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last) 319 struct proc *p; 320 struct exec_package *epp; 321 char *path; 322 struct exec_vmcmd_set *vcset; 323 u_long *entry; 324 struct elf_args *ap; 325 Elf_Addr *last; 326{ 327 int error, i; 328 struct nameidata nd; 329 struct vnode *vp; 330 struct vattr attr; 331 Elf_Ehdr eh; 332 Elf_Phdr *ph = NULL; 333 u_long phsize; 334 char *bp = NULL; 335 Elf_Addr addr = *last; 336 337 bp = path; 338 /* 339 * 1. open file 340 * 2. read filehdr 341 * 3. map text, data, and bss out of it using VM_* 342 */ 343 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); 344 if ((error = namei(&nd)) != 0) 345 return error; 346 vp = nd.ni_vp; 347 348 /* check for regular file */ 349 if (vp->v_type != VREG) { 350 error = EACCES; 351 goto badunlock; 352 } 353 354 /* get attributes */ 355 if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0) 356 goto badunlock; 357 358 /* 359 * Check mount point. Though we're not trying to exec this binary, 360 * we will be executing code from it, so if the mount point 361 * disallows execution or set-id-ness, we punt or kill the set-id. 362 */ 363 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 364 error = EACCES; 365 goto badunlock; 366 } 367 if (vp->v_mount->mnt_flag & MNT_NOSUID) 368 epp->ep_vap->va_mode &= ~(VSUID | VSGID); 369 370 /* 371 * Similarly, if it's not marked as executable, we don't allow 372 * it to be used. For root we have to see if any exec bit on. 373 */ 374 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 375 goto badunlock; 376 if ((attr.va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) { 377 error = EACCES; 378 goto badunlock; 379 } 380 381#ifdef notyet /* XXX cgd 960926 */ 382 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 383#endif 384 VOP_UNLOCK(vp); 385 386 if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh, 387 sizeof(eh))) != 0) 388 goto bad; 389 390 if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) 391 goto bad; 392 393 phsize = eh.e_phnum * sizeof(Elf_Phdr); 394 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 395 396 if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff, 397 (caddr_t) ph, phsize)) != 0) 398 goto bad; 399 400 /* 401 * Load all the necessary sections 402 */ 403 for (i = 0; i < eh.e_phnum; i++) { 404 u_long size = 0; 405 int prot = 0; 406 407 switch (ph[i].p_type) { 408 case Elf_pt_load: 409 ELFNAME(load_psection)(vcset, vp, &ph[i], &addr, 410 &size, &prot); 411 /* If entry is within this section it must be text */ 412 if (eh.e_entry >= ph[i].p_vaddr && 413 eh.e_entry < (ph[i].p_vaddr + size)) { 414 *entry = addr + eh.e_entry; 415 ap->arg_interp = addr; 416 } 417 addr += size; 418 break; 419 420 case Elf_pt_dynamic: 421 case Elf_pt_phdr: 422 case Elf_pt_note: 423 break; 424 425 default: 426 break; 427 } 428 } 429 430 free((char *)ph, M_TEMP); 431 *last = addr; 432 vrele(vp); 433 return 0; 434 435badunlock: 436 VOP_UNLOCK(vp); 437 438bad: 439 if (ph != NULL) 440 free((char *)ph, M_TEMP); 441#ifdef notyet /* XXX cgd 960926 */ 442 (maybe) VOP_CLOSE it 443#endif 444 vrele(vp); 445 return error; 446} 447 448/* 449 * exec_elf_makecmds(): Prepare an Elf binary's exec package 450 * 451 * First, set of the various offsets/lengths in the exec package. 452 * 453 * Then, mark the text image busy (so it can be demand paged) or error 454 * out if this is not possible. Finally, set up vmcmds for the 455 * text, data, bss, and stack segments. 456 */ 457int 458ELFNAME2(exec,makecmds)(p, epp) 459 struct proc *p; 460 struct exec_package *epp; 461{ 462 Elf_Ehdr *eh = epp->ep_hdr; 463 Elf_Phdr *ph, *pp; 464 Elf_Addr phdr = 0, pos = 0; 465 int error, i, n, nload; 466 char interp[MAXPATHLEN]; 467 u_long phsize; 468 469 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 470 return ENOEXEC; 471 472 if (ELFNAME(check_header)(eh, Elf_et_exec)) 473 return ENOEXEC; 474 475 /* 476 * check if vnode is in open for writing, because we want to 477 * demand-page out of it. if it is, don't do it, for various 478 * reasons 479 */ 480 if (epp->ep_vp->v_writecount != 0) { 481#ifdef DIAGNOSTIC 482 if (epp->ep_vp->v_flag & VTEXT) 483 panic("exec: a VTEXT vnode has writecount != 0\n"); 484#endif 485 return ETXTBSY; 486 } 487 /* 488 * Allocate space to hold all the program headers, and read them 489 * from the file 490 */ 491 phsize = eh->e_phnum * sizeof(Elf_Phdr); 492 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 493 494 if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, 495 (caddr_t) ph, phsize)) != 0) 496 goto bad; 497 498 epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 499 epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 500 501 interp[0] = '\0'; 502 503 for (i = 0; i < eh->e_phnum; i++) { 504 pp = &ph[i]; 505 if (pp->p_type == Elf_pt_interp) { 506 if (pp->p_filesz >= sizeof(interp)) 507 goto bad; 508 if ((error = ELFNAME(read_from)(p, epp->ep_vp, 509 pp->p_offset, (caddr_t) interp, 510 pp->p_filesz)) != 0) 511 goto bad; 512 break; 513 } 514 } 515 516 /* 517 * Setup things for native emulation. 518 */ 519 epp->ep_emul = &ELFNAMEEND(emul_netbsd); 520 pos = ELFDEFNNAME(NO_ADDR); 521 522 /* 523 * On the same architecture, we may be emulating different systems. 524 * See which one will accept this executable. This currently only 525 * applies to Linux and SVR4 on the i386. 526 * 527 * Probe functions would normally see if the interpreter (if any) 528 * exists. Emulation packages may possibly replace the interpreter in 529 * interp[] with a changed path (/emul/xxx/<path>), and also 530 * set the ep_emul field in the exec package structure. 531 */ 532 n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0]; 533 if (n != 0) { 534 error = ENOEXEC; 535 for (i = 0; i < n && error; i++) 536 error = ELFNAME(probe_funcs)[i](p, epp, eh, 537 interp, &pos); 538 539#ifdef notyet 540 /* 541 * We should really use a signature in our native binaries 542 * and have our own probe function for matching binaries, 543 * before trying the emulations. For now, if the emulation 544 * probes failed we default to native. 545 */ 546 if (error) 547 goto bad; 548#endif 549 } 550 551 /* 552 * Load all the necessary sections 553 */ 554 for (i = nload = 0; i < eh->e_phnum; i++) { 555 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 556 u_long size = 0; 557 int prot = 0; 558 559 pp = &ph[i]; 560 561 switch (ph[i].p_type) { 562 case Elf_pt_load: 563 /* 564 * XXX 565 * Can handle only 2 sections: text and data 566 */ 567 if (nload++ == 2) 568 goto bad; 569 ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, 570 &ph[i], &addr, &size, &prot); 571 572 /* 573 * Decide whether it's text or data by looking 574 * at the entry point. 575 */ 576 if (eh->e_entry >= addr && eh->e_entry < (addr + size)){ 577 epp->ep_taddr = addr; 578 epp->ep_tsize = size; 579 } else { 580 epp->ep_daddr = addr; 581 epp->ep_dsize = size; 582 } 583 break; 584 585 case Elf_pt_shlib: 586 error = ENOEXEC; 587 goto bad; 588 589 case Elf_pt_interp: 590 /* Already did this one */ 591 case Elf_pt_dynamic: 592 case Elf_pt_note: 593 break; 594 595 case Elf_pt_phdr: 596 /* Note address of program headers (in text segment) */ 597 phdr = pp->p_vaddr; 598 break; 599 600 default: 601 /* 602 * Not fatal; we don't need to understand everything. 603 */ 604 break; 605 } 606 } 607 608 /* 609 * If no position to load the interpreter was set by a probe 610 * function, pick the same address that a non-fixed mmap(0, ..) 611 * would (i.e. something safely out of the way). 612 */ 613 if (pos == ELFDEFNNAME(NO_ADDR) && 614 epp->ep_emul == &ELFNAMEEND(emul_netbsd)) 615 pos = round_page(epp->ep_daddr + MAXDSIZ); 616 617 /* 618 * Check if we found a dynamically linked binary and arrange to load 619 * it's interpreter 620 */ 621 if (interp[0]) { 622 struct elf_args *ap; 623 624 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 625 M_TEMP, M_WAITOK); 626 if ((error = ELFNAME(load_file)(p, epp, interp, 627 &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) { 628 free((char *)ap, M_TEMP); 629 goto bad; 630 } 631 pos += phsize; 632 ap->arg_phaddr = phdr; 633 634 ap->arg_phentsize = eh->e_phentsize; 635 ap->arg_phnum = eh->e_phnum; 636 ap->arg_entry = eh->e_entry; 637 638 epp->ep_emul_arg = ap; 639 } else 640 epp->ep_entry = eh->e_entry; 641 642#ifdef ELF_MAP_PAGE_ZERO 643 /* Dell SVR4 maps page zero, yeuch! */ 644 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, 645 VM_PROT_READ); 646#endif 647 free((char *)ph, M_TEMP); 648 epp->ep_vp->v_flag |= VTEXT; 649 return exec_elf_setup_stack(p, epp); 650 651bad: 652 free((char *)ph, M_TEMP); 653 kill_vmcmds(&epp->ep_vmcmds); 654 return ENOEXEC; 655} 656