exec_elf32.c revision 1.129
1/* $NetBSD: exec_elf32.c,v 1.129 2007/12/27 15:21:52 elad Exp $ */ 2 3/*- 4 * Copyright (c) 1994, 2000, 2005 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39/* 40 * Copyright (c) 1996 Christopher G. Demetriou 41 * All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. The name of the author may not be used to endorse or promote products 52 * derived from this software without specific prior written permission 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 55 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 56 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 57 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 58 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 59 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 60 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 61 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 62 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 63 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 64 */ 65 66#include <sys/cdefs.h> 67__KERNEL_RCSID(1, "$NetBSD: exec_elf32.c,v 1.129 2007/12/27 15:21:52 elad Exp $"); 68 69/* If not included by exec_elf64.c, ELFSIZE won't be defined. */ 70#ifndef ELFSIZE 71#define ELFSIZE 32 72#endif 73 74#ifdef _KERNEL_OPT 75#include "opt_pax.h" 76#endif /* _KERNEL_OPT */ 77 78#include <sys/param.h> 79#include <sys/proc.h> 80#include <sys/malloc.h> 81#include <sys/namei.h> 82#include <sys/vnode.h> 83#include <sys/exec.h> 84#include <sys/exec_elf.h> 85#include <sys/syscall.h> 86#include <sys/signalvar.h> 87#include <sys/mount.h> 88#include <sys/stat.h> 89#include <sys/kauth.h> 90#include <sys/bitops.h> 91 92#include <sys/cpu.h> 93#include <machine/reg.h> 94 95#include <compat/common/compat_util.h> 96 97#include <sys/pax.h> 98 99extern const struct emul emul_netbsd; 100 101#define elf_check_header ELFNAME(check_header) 102#define elf_copyargs ELFNAME(copyargs) 103#define elf_load_file ELFNAME(load_file) 104#define elf_load_psection ELFNAME(load_psection) 105#define exec_elf_makecmds ELFNAME2(exec,makecmds) 106#define netbsd_elf_signature ELFNAME2(netbsd,signature) 107#define netbsd_elf_probe ELFNAME2(netbsd,probe) 108 109int elf_load_file(struct lwp *, struct exec_package *, char *, 110 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); 111void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, 112 const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); 113 114int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 115int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 116 vaddr_t *); 117 118/* round up and down to page boundaries. */ 119#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 120#define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 121 122#define MAXPHNUM 50 123 124#ifdef PAX_ASLR 125/* 126 * We don't move this code in kern_pax.c because it is compiled twice. 127 */ 128static void 129pax_aslr_elf(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 130 Elf_Phdr *ph) 131{ 132 size_t pax_align = 0, pax_offset, i; 133 134 if (!pax_aslr_active(l)) 135 return; 136 137 /* 138 * find align XXX: not all sections might have the same 139 * alignment 140 */ 141 for (i = 0; i < eh->e_phnum; i++) 142 if (ph[i].p_type == PT_LOAD) { 143 pax_align = ph[i].p_align; 144 break; 145 } 146 147 if (pax_align == 0) 148 pax_align = PGSHIFT; 149#ifdef DEBUG_ASLR 150 uprintf("r=0x%x a=0x%x p=0x%x Delta=0x%lx\n", epp->ep_random, 151 ilog2(pax_align), PGSHIFT, PAX_ASLR_DELTA(epp->ep_random, 152 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN)); 153#endif 154 pax_offset = ELF_TRUNC(PAX_ASLR_DELTA(epp->ep_random, 155 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN), pax_align); 156 157 for (i = 0; i < eh->e_phnum; i++) 158 ph[i].p_vaddr += pax_offset; 159 eh->e_entry += pax_offset; 160#ifdef DEBUG_ASLR 161 uprintf("pax offset=0x%x entry=0x%x\n", 162 pax_offset, eh->e_entry); 163#endif 164} 165#endif /* PAX_ASLR */ 166 167/* 168 * Copy arguments onto the stack in the normal way, but add some 169 * extra information in case of dynamic binding. 170 */ 171int 172elf_copyargs(struct lwp *l, struct exec_package *pack, 173 struct ps_strings *arginfo, char **stackp, void *argp) 174{ 175 size_t len, vlen; 176 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 177 struct elf_args *ap; 178 int error; 179 180 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 181 return error; 182 183 a = ai; 184 execname = NULL; 185 186 /* 187 * Push extra arguments on the stack needed by dynamically 188 * linked binaries 189 */ 190 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 191 struct vattr *vap = pack->ep_vap; 192 193 a->a_type = AT_PHDR; 194 a->a_v = ap->arg_phaddr; 195 a++; 196 197 a->a_type = AT_PHENT; 198 a->a_v = ap->arg_phentsize; 199 a++; 200 201 a->a_type = AT_PHNUM; 202 a->a_v = ap->arg_phnum; 203 a++; 204 205 a->a_type = AT_PAGESZ; 206 a->a_v = PAGE_SIZE; 207 a++; 208 209 a->a_type = AT_BASE; 210 a->a_v = ap->arg_interp; 211 a++; 212 213 a->a_type = AT_FLAGS; 214 a->a_v = 0; 215 a++; 216 217 a->a_type = AT_ENTRY; 218 a->a_v = ap->arg_entry; 219 a++; 220 221 a->a_type = AT_EUID; 222 if (vap->va_mode & S_ISUID) 223 a->a_v = vap->va_uid; 224 else 225 a->a_v = kauth_cred_geteuid(l->l_cred); 226 a++; 227 228 a->a_type = AT_RUID; 229 a->a_v = kauth_cred_getuid(l->l_cred); 230 a++; 231 232 a->a_type = AT_EGID; 233 if (vap->va_mode & S_ISGID) 234 a->a_v = vap->va_gid; 235 else 236 a->a_v = kauth_cred_getegid(l->l_cred); 237 a++; 238 239 a->a_type = AT_RGID; 240 a->a_v = kauth_cred_getgid(l->l_cred); 241 a++; 242 243 if (pack->ep_path) { 244 execname = a; 245 a->a_type = AT_SUN_EXECNAME; 246 a++; 247 } 248 249 free(ap, M_TEMP); 250 pack->ep_emul_arg = NULL; 251 } 252 253 a->a_type = AT_NULL; 254 a->a_v = 0; 255 a++; 256 257 vlen = (a - ai) * sizeof(AuxInfo); 258 259 if (execname) { 260 char *path = pack->ep_path; 261 execname->a_v = (intptr_t)(*stackp + vlen); 262 len = strlen(path) + 1; 263 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 264 return error; 265 len = ALIGN(len); 266 } else 267 len = 0; 268 269 if ((error = copyout(ai, *stackp, vlen)) != 0) 270 return error; 271 *stackp += vlen + len; 272 273 return 0; 274} 275 276/* 277 * elf_check_header(): 278 * 279 * Check header for validity; return 0 of ok ENOEXEC if error 280 */ 281int 282elf_check_header(Elf_Ehdr *eh, int type) 283{ 284 285 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 286 eh->e_ident[EI_CLASS] != ELFCLASS) 287 return ENOEXEC; 288 289 switch (eh->e_machine) { 290 291 ELFDEFNNAME(MACHDEP_ID_CASES) 292 293 default: 294 return ENOEXEC; 295 } 296 297 if (ELF_EHDR_FLAGS_OK(eh) == 0) 298 return ENOEXEC; 299 300 if (eh->e_type != type) 301 return ENOEXEC; 302 303 if (eh->e_shnum > 32768 || eh->e_phnum > 128) 304 return ENOEXEC; 305 306 return 0; 307} 308 309/* 310 * elf_load_psection(): 311 * 312 * Load a psection at the appropriate address 313 */ 314void 315elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 316 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 317{ 318 u_long msize, psize, rm, rf; 319 long diff, offset; 320 321 /* 322 * If the user specified an address, then we load there. 323 */ 324 if (*addr == ELFDEFNNAME(NO_ADDR)) 325 *addr = ph->p_vaddr; 326 327 if (ph->p_align > 1) { 328 /* 329 * Make sure we are virtually aligned as we are supposed to be. 330 */ 331 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 332 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 333 /* 334 * But make sure to not map any pages before the start of the 335 * psection by limiting the difference to within a page. 336 */ 337 diff &= PAGE_MASK; 338 } else 339 diff = 0; 340 341 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 342 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 343 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 344 345 /* 346 * Adjust everything so it all starts on a page boundary. 347 */ 348 *addr -= diff; 349 offset = ph->p_offset - diff; 350 *size = ph->p_filesz + diff; 351 msize = ph->p_memsz + diff; 352 353 if (ph->p_align >= PAGE_SIZE) { 354 if ((ph->p_flags & PF_W) != 0) { 355 /* 356 * Because the pagedvn pager can't handle zero fill 357 * of the last data page if it's not page aligned we 358 * map the last page readvn. 359 */ 360 psize = trunc_page(*size); 361 } else { 362 psize = round_page(*size); 363 } 364 } else { 365 psize = *size; 366 } 367 368 if (psize > 0) { 369 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 370 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 371 offset, *prot, flags); 372 flags &= VMCMD_RELATIVE; 373 } 374 if (psize < *size) { 375 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 376 *addr + psize, vp, offset + psize, *prot, flags); 377 } 378 379 /* 380 * Check if we need to extend the size of the segment (does 381 * bss extend page the next page boundary)? 382 */ 383 rm = round_page(*addr + msize); 384 rf = round_page(*addr + *size); 385 386 if (rm != rf) { 387 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 388 0, *prot, flags & VMCMD_RELATIVE); 389 *size = msize; 390 } 391} 392 393/* 394 * elf_load_file(): 395 * 396 * Load a file (interpreter/library) pointed to by path 397 * [stolen from coff_load_shlib()]. Made slightly generic 398 * so it might be used externally. 399 */ 400int 401elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 402 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 403 Elf_Addr *last) 404{ 405 int error, i; 406 struct vnode *vp; 407 struct vattr attr; 408 Elf_Ehdr eh; 409 Elf_Phdr *ph = NULL; 410 const Elf_Phdr *ph0; 411 const Elf_Phdr *base_ph; 412 const Elf_Phdr *last_ph; 413 u_long phsize; 414 Elf_Addr addr = *last; 415 struct proc *p; 416 417 p = l->l_proc; 418 419 /* 420 * 1. open file 421 * 2. read filehdr 422 * 3. map text, data, and bss out of it using VM_* 423 */ 424 vp = epp->ep_interp; 425 if (vp == NULL) { 426 error = emul_find_interp(l, epp, path); 427 if (error != 0) 428 return error; 429 vp = epp->ep_interp; 430 } 431 /* We'll tidy this ourselves - otherwise we have locking issues */ 432 epp->ep_interp = NULL; 433 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 434 435 /* 436 * Similarly, if it's not marked as executable, or it's not a regular 437 * file, we don't allow it to be used. 438 */ 439 if (vp->v_type != VREG) { 440 error = EACCES; 441 goto badunlock; 442 } 443 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 444 goto badunlock; 445 446 /* get attributes */ 447 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 448 goto badunlock; 449 450 /* 451 * Check mount point. Though we're not trying to exec this binary, 452 * we will be executing code from it, so if the mount point 453 * disallows execution or set-id-ness, we punt or kill the set-id. 454 */ 455 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 456 error = EACCES; 457 goto badunlock; 458 } 459 if (vp->v_mount->mnt_flag & MNT_NOSUID) 460 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 461 462#ifdef notyet /* XXX cgd 960926 */ 463 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 464#endif 465 466 error = vn_marktext(vp); 467 if (error) 468 goto badunlock; 469 470 VOP_UNLOCK(vp, 0); 471 472 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 473 goto bad; 474 475 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 476 goto bad; 477 478 if (eh.e_phnum > MAXPHNUM) 479 goto bad; 480 481 phsize = eh.e_phnum * sizeof(Elf_Phdr); 482 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 483 484 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 485 goto bad; 486 487#ifdef ELF_INTERP_NON_RELOCATABLE 488 /* 489 * Evil hack: Only MIPS should be non-relocatable, and the 490 * psections should have a high address (typically 0x5ffe0000). 491 * If it's now relocatable, it should be linked at 0 and the 492 * psections should have zeros in the upper part of the address. 493 * Otherwise, force the load at the linked address. 494 */ 495 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 496 *last = ELFDEFNNAME(NO_ADDR); 497#endif 498 499 /* 500 * If no position to load the interpreter was set by a probe 501 * function, pick the same address that a non-fixed mmap(0, ..) 502 * would (i.e. something safely out of the way). 503 */ 504 if (*last == ELFDEFNNAME(NO_ADDR)) { 505 u_long limit = 0; 506 /* 507 * Find the start and ending addresses of the psections to 508 * be loaded. This will give us the size. 509 */ 510 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 511 i++, ph0++) { 512 if (ph0->p_type == PT_LOAD) { 513 u_long psize = ph0->p_vaddr + ph0->p_memsz; 514 if (base_ph == NULL) 515 base_ph = ph0; 516 if (psize > limit) 517 limit = psize; 518 } 519 } 520 521 if (base_ph == NULL) { 522 error = ENOEXEC; 523 goto bad; 524 } 525 526 /* 527 * Now compute the size and load address. 528 */ 529 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 530 epp->ep_daddr, 531 round_page(limit) - trunc_page(base_ph->p_vaddr)); 532 } else 533 addr = *last; /* may be ELF_LINK_ADDR */ 534 535 /* 536 * Load all the necessary sections 537 */ 538 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 539 i < eh.e_phnum; i++, ph0++) { 540 switch (ph0->p_type) { 541 case PT_LOAD: { 542 u_long size; 543 int prot = 0; 544 int flags; 545 546 if (base_ph == NULL) { 547 /* 548 * First encountered psection is always the 549 * base psection. Make sure it's aligned 550 * properly (align down for topdown and align 551 * upwards for not topdown). 552 */ 553 base_ph = ph0; 554 flags = VMCMD_BASE; 555 if (addr == ELF_LINK_ADDR) 556 addr = ph0->p_vaddr; 557 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 558 addr = ELF_TRUNC(addr, ph0->p_align); 559 else 560 addr = ELF_ROUND(addr, ph0->p_align); 561 } else { 562 u_long limit = round_page(last_ph->p_vaddr 563 + last_ph->p_memsz); 564 u_long base = trunc_page(ph0->p_vaddr); 565 566 /* 567 * If there is a gap in between the psections, 568 * map it as inaccessible so nothing else 569 * mmap'ed will be placed there. 570 */ 571 if (limit != base) { 572 NEW_VMCMD2(vcset, vmcmd_map_zero, 573 base - limit, 574 limit - base_ph->p_vaddr, NULLVP, 575 0, VM_PROT_NONE, VMCMD_RELATIVE); 576 } 577 578 addr = ph0->p_vaddr - base_ph->p_vaddr; 579 flags = VMCMD_RELATIVE; 580 } 581 last_ph = ph0; 582 elf_load_psection(vcset, vp, &ph[i], &addr, 583 &size, &prot, flags); 584 /* 585 * If entry is within this psection then this 586 * must contain the .text section. *entryoff is 587 * relative to the base psection. 588 */ 589 if (eh.e_entry >= ph0->p_vaddr && 590 eh.e_entry < (ph0->p_vaddr + size)) { 591 *entryoff = eh.e_entry - base_ph->p_vaddr; 592 } 593 addr += size; 594 break; 595 } 596 597 case PT_DYNAMIC: 598 case PT_PHDR: 599 break; 600 601 case PT_NOTE: 602 break; 603 604 default: 605 break; 606 } 607 } 608 609 free(ph, M_TEMP); 610 /* 611 * This value is ignored if TOPDOWN. 612 */ 613 *last = addr; 614 vrele(vp); 615 return 0; 616 617badunlock: 618 VOP_UNLOCK(vp, 0); 619 620bad: 621 if (ph != NULL) 622 free(ph, M_TEMP); 623#ifdef notyet /* XXX cgd 960926 */ 624 (maybe) VOP_CLOSE it 625#endif 626 vrele(vp); 627 return error; 628} 629 630/* 631 * exec_elf_makecmds(): Prepare an Elf binary's exec package 632 * 633 * First, set of the various offsets/lengths in the exec package. 634 * 635 * Then, mark the text image busy (so it can be demand paged) or error 636 * out if this is not possible. Finally, set up vmcmds for the 637 * text, data, bss, and stack segments. 638 */ 639int 640exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 641{ 642 Elf_Ehdr *eh = epp->ep_hdr; 643 Elf_Phdr *ph, *pp; 644 Elf_Addr phdr = 0, pos = 0; 645 int error, i, nload; 646 char *interp = NULL; 647 u_long phsize; 648 struct proc *p; 649 bool is_dyn; 650 651 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 652 return ENOEXEC; 653 654 is_dyn = elf_check_header(eh, ET_DYN) == 0; 655 /* 656 * XXX allow for executing shared objects. It seems silly 657 * but other ELF-based systems allow it as well. 658 */ 659 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 660 return ENOEXEC; 661 662 if (eh->e_phnum > MAXPHNUM) 663 return ENOEXEC; 664 665 error = vn_marktext(epp->ep_vp); 666 if (error) 667 return error; 668 669 /* 670 * Allocate space to hold all the program headers, and read them 671 * from the file 672 */ 673 p = l->l_proc; 674 phsize = eh->e_phnum * sizeof(Elf_Phdr); 675 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 676 677 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 678 0) 679 goto bad; 680 681 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 682 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 683 684 for (i = 0; i < eh->e_phnum; i++) { 685 pp = &ph[i]; 686 if (pp->p_type == PT_INTERP) { 687 if (pp->p_filesz >= MAXPATHLEN) 688 goto bad; 689 interp = PNBUF_GET(); 690 interp[0] = '\0'; 691 if ((error = exec_read_from(l, epp->ep_vp, 692 pp->p_offset, interp, pp->p_filesz)) != 0) 693 goto bad; 694 break; 695 } 696 } 697 698 /* 699 * On the same architecture, we may be emulating different systems. 700 * See which one will accept this executable. 701 * 702 * Probe functions would normally see if the interpreter (if any) 703 * exists. Emulation packages may possibly replace the interpreter in 704 * interp[] with a changed path (/emul/xxx/<path>). 705 */ 706 pos = ELFDEFNNAME(NO_ADDR); 707 if (epp->ep_esch->u.elf_probe_func) { 708 vaddr_t startp = (vaddr_t)pos; 709 710 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 711 &startp); 712 if (error) 713 goto bad; 714 pos = (Elf_Addr)startp; 715 } 716 717#if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 718 if (epp->ep_pax_flags) 719 pax_adjust(l, epp->ep_pax_flags); 720#endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 721 722#ifdef PAX_ASLR 723 if (is_dyn) 724 pax_aslr_elf(l, epp, eh, ph); 725#endif /* PAX_ASLR */ 726 727 /* 728 * Load all the necessary sections 729 */ 730 for (i = nload = 0; i < eh->e_phnum; i++) { 731 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 732 u_long size = 0; 733 int prot = 0; 734 735 pp = &ph[i]; 736 737 switch (ph[i].p_type) { 738 case PT_LOAD: 739 /* 740 * XXX 741 * Can handle only 2 sections: text and data 742 */ 743 if (nload++ == 2) 744 goto bad; 745 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 746 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 747 748 /* 749 * Decide whether it's text or data by looking 750 * at the entry point. 751 */ 752 if (eh->e_entry >= addr && 753 eh->e_entry < (addr + size)) { 754 epp->ep_taddr = addr; 755 epp->ep_tsize = size; 756 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 757 epp->ep_daddr = addr; 758 epp->ep_dsize = size; 759 } 760 } else { 761 epp->ep_daddr = addr; 762 epp->ep_dsize = size; 763 } 764 break; 765 766 case PT_SHLIB: 767 /* SCO has these sections. */ 768 case PT_INTERP: 769 /* Already did this one. */ 770 case PT_DYNAMIC: 771 break; 772 case PT_NOTE: 773 break; 774 case PT_PHDR: 775 /* Note address of program headers (in text segment) */ 776 phdr = pp->p_vaddr; 777 break; 778 779 default: 780 /* 781 * Not fatal; we don't need to understand everything. 782 */ 783 break; 784 } 785 } 786 787 /* 788 * Check if we found a dynamically linked binary and arrange to load 789 * its interpreter 790 */ 791 if (interp) { 792 struct elf_args *ap; 793 int j = epp->ep_vmcmds.evs_used; 794 u_long interp_offset; 795 796 MALLOC(ap, struct elf_args *, sizeof(struct elf_args), 797 M_TEMP, M_WAITOK); 798 if ((error = elf_load_file(l, epp, interp, 799 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 800 FREE(ap, M_TEMP); 801 goto bad; 802 } 803 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 804 epp->ep_entry = ap->arg_interp + interp_offset; 805 ap->arg_phaddr = phdr; 806 807 ap->arg_phentsize = eh->e_phentsize; 808 ap->arg_phnum = eh->e_phnum; 809 ap->arg_entry = eh->e_entry; 810 811 epp->ep_emul_arg = ap; 812 813 PNBUF_PUT(interp); 814 } else 815 epp->ep_entry = eh->e_entry; 816 817#ifdef ELF_MAP_PAGE_ZERO 818 /* Dell SVR4 maps page zero, yeuch! */ 819 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 820 epp->ep_vp, 0, VM_PROT_READ); 821#endif 822 free(ph, M_TEMP); 823 return (*epp->ep_esch->es_setup_stack)(l, epp); 824 825bad: 826 if (interp) 827 PNBUF_PUT(interp); 828 free(ph, M_TEMP); 829 kill_vmcmds(&epp->ep_vmcmds); 830 return ENOEXEC; 831} 832 833int 834netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 835 Elf_Ehdr *eh) 836{ 837 size_t i; 838 Elf_Phdr *ph; 839 size_t phsize; 840 int error; 841 int isnetbsd = 0; 842 char *ndata; 843 844 epp->ep_pax_flags = 0; 845 if (eh->e_phnum > MAXPHNUM) 846 return ENOEXEC; 847 848 phsize = eh->e_phnum * sizeof(Elf_Phdr); 849 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 850 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 851 if (error) 852 goto out; 853 854 for (i = 0; i < eh->e_phnum; i++) { 855 Elf_Phdr *ephp = &ph[i]; 856 Elf_Nhdr *np; 857 858 if (ephp->p_type != PT_NOTE || 859 ephp->p_filesz > 1024 || 860 ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 861 continue; 862 863 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); 864 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, 865 ephp->p_filesz); 866 if (error) 867 goto next; 868 869 ndata = (char *)(np + 1); 870 switch (np->n_type) { 871 case ELF_NOTE_TYPE_NETBSD_TAG: 872 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 873 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 874 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 875 ELF_NOTE_NETBSD_NAMESZ)) 876 goto next; 877 isnetbsd = 1; 878 break; 879 880 case ELF_NOTE_TYPE_PAX_TAG: 881 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 882 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 883 memcmp(ndata, ELF_NOTE_PAX_NAME, 884 ELF_NOTE_PAX_NAMESZ)) 885 goto next; 886 (void)memcpy(&epp->ep_pax_flags, 887 ndata + ELF_NOTE_PAX_NAMESZ, 888 sizeof(epp->ep_pax_flags)); 889 break; 890 891 default: 892 break; 893 } 894 895next: 896 free(np, M_TEMP); 897 continue; 898 } 899 900 error = isnetbsd ? 0 : ENOEXEC; 901out: 902 free(ph, M_TEMP); 903 return error; 904} 905 906int 907netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 908 vaddr_t *pos) 909{ 910 int error; 911 912 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 913 return error; 914#ifdef ELF_INTERP_NON_RELOCATABLE 915 *pos = ELF_LINK_ADDR; 916#endif 917 return 0; 918} 919