1 /* $NetBSD: exec_elf32.c,v 1.135 2008/07/18 21:29:48 christos 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1996 Christopher G. Demetriou 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. The name of the author may not be used to endorse or promote products 45 * derived from this software without specific prior written permission 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 48 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 50 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 51 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 52 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 53 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 54 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 55 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 56 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 57 */ 58 59 #include <sys/cdefs.h> 60 __KERNEL_RCSID(1, "$NetBSD: exec_elf32.c,v 1.135 2008/07/18 21:29:48 christos Exp $"); 61 62 /* If not included by exec_elf64.c, ELFSIZE won't be defined. */ 63 #ifndef ELFSIZE 64 #define ELFSIZE 32 65 #endif 66 67 #ifdef _KERNEL_OPT 68 #include "opt_pax.h" 69 #endif /* _KERNEL_OPT */ 70 71 #include <sys/param.h> 72 #include <sys/proc.h> 73 #include <sys/malloc.h> 74 #include <sys/kmem.h> 75 #include <sys/namei.h> 76 #include <sys/vnode.h> 77 #include <sys/exec.h> 78 #include <sys/exec_elf.h> 79 #include <sys/syscall.h> 80 #include <sys/signalvar.h> 81 #include <sys/mount.h> 82 #include <sys/stat.h> 83 #include <sys/kauth.h> 84 #include <sys/bitops.h> 85 86 #include <sys/cpu.h> 87 #include <machine/reg.h> 88 89 #include <compat/common/compat_util.h> 90 91 #include <sys/pax.h> 92 93 extern const struct emul emul_netbsd; 94 95 #define elf_check_header ELFNAME(check_header) 96 #define elf_copyargs ELFNAME(copyargs) 97 #define elf_load_file ELFNAME(load_file) 98 #define elf_load_psection ELFNAME(load_psection) 99 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 100 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 101 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 102 103 int elf_load_file(struct lwp *, struct exec_package *, char *, 104 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); 105 void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, 106 const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); 107 108 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 109 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 110 vaddr_t *); 111 112 /* round up and down to page boundaries. */ 113 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 114 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 115 116 #define MAXPHNUM 50 117 118 #ifdef PAX_ASLR 119 /* 120 * We don't move this code in kern_pax.c because it is compiled twice. 121 */ 122 static void 123 pax_aslr_elf(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 124 Elf_Phdr *ph) 125 { 126 size_t pax_align = 0, pax_offset, i; 127 uint32_t r; 128 129 if (!pax_aslr_active(l)) 130 return; 131 132 /* 133 * find align XXX: not all sections might have the same 134 * alignment 135 */ 136 for (i = 0; i < eh->e_phnum; i++) 137 if (ph[i].p_type == PT_LOAD) { 138 pax_align = ph[i].p_align; 139 break; 140 } 141 142 r = arc4random(); 143 144 if (pax_align == 0) 145 pax_align = PGSHIFT; 146 #ifdef DEBUG_ASLR 147 uprintf("r=0x%x a=0x%x p=0x%x Delta=0x%lx\n", r, 148 ilog2(pax_align), PGSHIFT, PAX_ASLR_DELTA(r, 149 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN)); 150 #endif 151 pax_offset = ELF_TRUNC(PAX_ASLR_DELTA(r, 152 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN), pax_align); 153 154 for (i = 0; i < eh->e_phnum; i++) 155 ph[i].p_vaddr += pax_offset; 156 eh->e_entry += pax_offset; 157 #ifdef DEBUG_ASLR 158 uprintf("pax offset=0x%zx entry=0x%llx\n", 159 pax_offset, (unsigned long long)eh->e_entry); 160 #endif 161 } 162 #endif /* PAX_ASLR */ 163 164 /* 165 * Copy arguments onto the stack in the normal way, but add some 166 * extra information in case of dynamic binding. 167 */ 168 int 169 elf_copyargs(struct lwp *l, struct exec_package *pack, 170 struct ps_strings *arginfo, char **stackp, void *argp) 171 { 172 size_t len, vlen; 173 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 174 struct elf_args *ap; 175 int error; 176 177 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 178 return error; 179 180 a = ai; 181 execname = NULL; 182 183 /* 184 * Push extra arguments on the stack needed by dynamically 185 * linked binaries 186 */ 187 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 188 struct vattr *vap = pack->ep_vap; 189 190 a->a_type = AT_PHDR; 191 a->a_v = ap->arg_phaddr; 192 a++; 193 194 a->a_type = AT_PHENT; 195 a->a_v = ap->arg_phentsize; 196 a++; 197 198 a->a_type = AT_PHNUM; 199 a->a_v = ap->arg_phnum; 200 a++; 201 202 a->a_type = AT_PAGESZ; 203 a->a_v = PAGE_SIZE; 204 a++; 205 206 a->a_type = AT_BASE; 207 a->a_v = ap->arg_interp; 208 a++; 209 210 a->a_type = AT_FLAGS; 211 a->a_v = 0; 212 a++; 213 214 a->a_type = AT_ENTRY; 215 a->a_v = ap->arg_entry; 216 a++; 217 218 a->a_type = AT_EUID; 219 if (vap->va_mode & S_ISUID) 220 a->a_v = vap->va_uid; 221 else 222 a->a_v = kauth_cred_geteuid(l->l_cred); 223 a++; 224 225 a->a_type = AT_RUID; 226 a->a_v = kauth_cred_getuid(l->l_cred); 227 a++; 228 229 a->a_type = AT_EGID; 230 if (vap->va_mode & S_ISGID) 231 a->a_v = vap->va_gid; 232 else 233 a->a_v = kauth_cred_getegid(l->l_cred); 234 a++; 235 236 a->a_type = AT_RGID; 237 a->a_v = kauth_cred_getgid(l->l_cred); 238 a++; 239 240 if (pack->ep_path) { 241 execname = a; 242 a->a_type = AT_SUN_EXECNAME; 243 a++; 244 } 245 246 free(ap, M_TEMP); 247 pack->ep_emul_arg = NULL; 248 } 249 250 a->a_type = AT_NULL; 251 a->a_v = 0; 252 a++; 253 254 vlen = (a - ai) * sizeof(AuxInfo); 255 256 if (execname) { 257 char *path = pack->ep_path; 258 execname->a_v = (intptr_t)(*stackp + vlen); 259 len = strlen(path) + 1; 260 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 261 return error; 262 len = ALIGN(len); 263 } else 264 len = 0; 265 266 if ((error = copyout(ai, *stackp, vlen)) != 0) 267 return error; 268 *stackp += vlen + len; 269 270 return 0; 271 } 272 273 /* 274 * elf_check_header(): 275 * 276 * Check header for validity; return 0 of ok ENOEXEC if error 277 */ 278 int 279 elf_check_header(Elf_Ehdr *eh, int type) 280 { 281 282 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 283 eh->e_ident[EI_CLASS] != ELFCLASS) 284 return ENOEXEC; 285 286 switch (eh->e_machine) { 287 288 ELFDEFNNAME(MACHDEP_ID_CASES) 289 290 default: 291 return ENOEXEC; 292 } 293 294 if (ELF_EHDR_FLAGS_OK(eh) == 0) 295 return ENOEXEC; 296 297 if (eh->e_type != type) 298 return ENOEXEC; 299 300 if (eh->e_shnum > 32768 || eh->e_phnum > 128) 301 return ENOEXEC; 302 303 return 0; 304 } 305 306 /* 307 * elf_load_psection(): 308 * 309 * Load a psection at the appropriate address 310 */ 311 void 312 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 313 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 314 { 315 u_long msize, psize, rm, rf; 316 long diff, offset; 317 318 /* 319 * If the user specified an address, then we load there. 320 */ 321 if (*addr == ELFDEFNNAME(NO_ADDR)) 322 *addr = ph->p_vaddr; 323 324 if (ph->p_align > 1) { 325 /* 326 * Make sure we are virtually aligned as we are supposed to be. 327 */ 328 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 329 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 330 /* 331 * But make sure to not map any pages before the start of the 332 * psection by limiting the difference to within a page. 333 */ 334 diff &= PAGE_MASK; 335 } else 336 diff = 0; 337 338 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 339 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 340 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 341 342 /* 343 * Adjust everything so it all starts on a page boundary. 344 */ 345 *addr -= diff; 346 offset = ph->p_offset - diff; 347 *size = ph->p_filesz + diff; 348 msize = ph->p_memsz + diff; 349 350 if (ph->p_align >= PAGE_SIZE) { 351 if ((ph->p_flags & PF_W) != 0) { 352 /* 353 * Because the pagedvn pager can't handle zero fill 354 * of the last data page if it's not page aligned we 355 * map the last page readvn. 356 */ 357 psize = trunc_page(*size); 358 } else { 359 psize = round_page(*size); 360 } 361 } else { 362 psize = *size; 363 } 364 365 if (psize > 0) { 366 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 367 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 368 offset, *prot, flags); 369 flags &= VMCMD_RELATIVE; 370 } 371 if (psize < *size) { 372 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 373 *addr + psize, vp, offset + psize, *prot, flags); 374 } 375 376 /* 377 * Check if we need to extend the size of the segment (does 378 * bss extend page the next page boundary)? 379 */ 380 rm = round_page(*addr + msize); 381 rf = round_page(*addr + *size); 382 383 if (rm != rf) { 384 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 385 0, *prot, flags & VMCMD_RELATIVE); 386 *size = msize; 387 } 388 } 389 390 /* 391 * elf_load_file(): 392 * 393 * Load a file (interpreter/library) pointed to by path 394 * [stolen from coff_load_shlib()]. Made slightly generic 395 * so it might be used externally. 396 */ 397 int 398 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 399 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 400 Elf_Addr *last) 401 { 402 int error, i; 403 struct vnode *vp; 404 struct vattr attr; 405 Elf_Ehdr eh; 406 Elf_Phdr *ph = NULL; 407 const Elf_Phdr *ph0; 408 const Elf_Phdr *base_ph; 409 const Elf_Phdr *last_ph; 410 u_long phsize; 411 Elf_Addr addr = *last; 412 struct proc *p; 413 414 p = l->l_proc; 415 416 /* 417 * 1. open file 418 * 2. read filehdr 419 * 3. map text, data, and bss out of it using VM_* 420 */ 421 vp = epp->ep_interp; 422 if (vp == NULL) { 423 error = emul_find_interp(l, epp, path); 424 if (error != 0) 425 return error; 426 vp = epp->ep_interp; 427 } 428 /* We'll tidy this ourselves - otherwise we have locking issues */ 429 epp->ep_interp = NULL; 430 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 431 432 /* 433 * Similarly, if it's not marked as executable, or it's not a regular 434 * file, we don't allow it to be used. 435 */ 436 if (vp->v_type != VREG) { 437 error = EACCES; 438 goto badunlock; 439 } 440 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 441 goto badunlock; 442 443 /* get attributes */ 444 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 445 goto badunlock; 446 447 /* 448 * Check mount point. Though we're not trying to exec this binary, 449 * we will be executing code from it, so if the mount point 450 * disallows execution or set-id-ness, we punt or kill the set-id. 451 */ 452 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 453 error = EACCES; 454 goto badunlock; 455 } 456 if (vp->v_mount->mnt_flag & MNT_NOSUID) 457 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 458 459 #ifdef notyet /* XXX cgd 960926 */ 460 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 461 #endif 462 463 error = vn_marktext(vp); 464 if (error) 465 goto badunlock; 466 467 VOP_UNLOCK(vp, 0); 468 469 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 470 goto bad; 471 472 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 473 goto bad; 474 475 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 476 error = ENOEXEC; 477 goto bad; 478 } 479 480 phsize = eh.e_phnum * sizeof(Elf_Phdr); 481 ph = kmem_alloc(phsize, KM_SLEEP); 482 483 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 484 goto bad; 485 486 #ifdef ELF_INTERP_NON_RELOCATABLE 487 /* 488 * Evil hack: Only MIPS should be non-relocatable, and the 489 * psections should have a high address (typically 0x5ffe0000). 490 * If it's now relocatable, it should be linked at 0 and the 491 * psections should have zeros in the upper part of the address. 492 * Otherwise, force the load at the linked address. 493 */ 494 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 495 *last = ELFDEFNNAME(NO_ADDR); 496 #endif 497 498 /* 499 * If no position to load the interpreter was set by a probe 500 * function, pick the same address that a non-fixed mmap(0, ..) 501 * would (i.e. something safely out of the way). 502 */ 503 if (*last == ELFDEFNNAME(NO_ADDR)) { 504 u_long limit = 0; 505 /* 506 * Find the start and ending addresses of the psections to 507 * be loaded. This will give us the size. 508 */ 509 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 510 i++, ph0++) { 511 if (ph0->p_type == PT_LOAD) { 512 u_long psize = ph0->p_vaddr + ph0->p_memsz; 513 if (base_ph == NULL) 514 base_ph = ph0; 515 if (psize > limit) 516 limit = psize; 517 } 518 } 519 520 if (base_ph == NULL) { 521 error = ENOEXEC; 522 goto bad; 523 } 524 525 /* 526 * Now compute the size and load address. 527 */ 528 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 529 epp->ep_daddr, 530 round_page(limit) - trunc_page(base_ph->p_vaddr)); 531 } else 532 addr = *last; /* may be ELF_LINK_ADDR */ 533 534 /* 535 * Load all the necessary sections 536 */ 537 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 538 i < eh.e_phnum; i++, ph0++) { 539 switch (ph0->p_type) { 540 case PT_LOAD: { 541 u_long size; 542 int prot = 0; 543 int flags; 544 545 if (base_ph == NULL) { 546 /* 547 * First encountered psection is always the 548 * base psection. Make sure it's aligned 549 * properly (align down for topdown and align 550 * upwards for not topdown). 551 */ 552 base_ph = ph0; 553 flags = VMCMD_BASE; 554 if (addr == ELF_LINK_ADDR) 555 addr = ph0->p_vaddr; 556 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 557 addr = ELF_TRUNC(addr, ph0->p_align); 558 else 559 addr = ELF_ROUND(addr, ph0->p_align); 560 } else { 561 u_long limit = round_page(last_ph->p_vaddr 562 + last_ph->p_memsz); 563 u_long base = trunc_page(ph0->p_vaddr); 564 565 /* 566 * If there is a gap in between the psections, 567 * map it as inaccessible so nothing else 568 * mmap'ed will be placed there. 569 */ 570 if (limit != base) { 571 NEW_VMCMD2(vcset, vmcmd_map_zero, 572 base - limit, 573 limit - base_ph->p_vaddr, NULLVP, 574 0, VM_PROT_NONE, VMCMD_RELATIVE); 575 } 576 577 addr = ph0->p_vaddr - base_ph->p_vaddr; 578 flags = VMCMD_RELATIVE; 579 } 580 last_ph = ph0; 581 elf_load_psection(vcset, vp, &ph[i], &addr, 582 &size, &prot, flags); 583 /* 584 * If entry is within this psection then this 585 * must contain the .text section. *entryoff is 586 * relative to the base psection. 587 */ 588 if (eh.e_entry >= ph0->p_vaddr && 589 eh.e_entry < (ph0->p_vaddr + size)) { 590 *entryoff = eh.e_entry - base_ph->p_vaddr; 591 } 592 addr += size; 593 break; 594 } 595 596 case PT_DYNAMIC: 597 case PT_PHDR: 598 break; 599 600 case PT_NOTE: 601 break; 602 603 default: 604 break; 605 } 606 } 607 608 kmem_free(ph, phsize); 609 /* 610 * This value is ignored if TOPDOWN. 611 */ 612 *last = addr; 613 vrele(vp); 614 return 0; 615 616 badunlock: 617 VOP_UNLOCK(vp, 0); 618 619 bad: 620 if (ph != NULL) 621 kmem_free(ph, phsize); 622 #ifdef notyet /* XXX cgd 960926 */ 623 (maybe) VOP_CLOSE it 624 #endif 625 vrele(vp); 626 return error; 627 } 628 629 /* 630 * exec_elf_makecmds(): Prepare an Elf binary's exec package 631 * 632 * First, set of the various offsets/lengths in the exec package. 633 * 634 * Then, mark the text image busy (so it can be demand paged) or error 635 * out if this is not possible. Finally, set up vmcmds for the 636 * text, data, bss, and stack segments. 637 */ 638 int 639 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 640 { 641 Elf_Ehdr *eh = epp->ep_hdr; 642 Elf_Phdr *ph, *pp; 643 Elf_Addr phdr = 0, pos = 0; 644 int error, i, nload; 645 char *interp = NULL; 646 u_long phsize; 647 struct proc *p; 648 bool is_dyn; 649 650 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 651 return ENOEXEC; 652 653 is_dyn = elf_check_header(eh, ET_DYN) == 0; 654 /* 655 * XXX allow for executing shared objects. It seems silly 656 * but other ELF-based systems allow it as well. 657 */ 658 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 659 return ENOEXEC; 660 661 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 662 return ENOEXEC; 663 664 error = vn_marktext(epp->ep_vp); 665 if (error) 666 return error; 667 668 /* 669 * Allocate space to hold all the program headers, and read them 670 * from the file 671 */ 672 p = l->l_proc; 673 phsize = eh->e_phnum * sizeof(Elf_Phdr); 674 ph = kmem_alloc(phsize, KM_SLEEP); 675 676 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 677 0) 678 goto bad; 679 680 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 681 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 682 683 for (i = 0; i < eh->e_phnum; i++) { 684 pp = &ph[i]; 685 if (pp->p_type == PT_INTERP) { 686 if (pp->p_filesz >= MAXPATHLEN) { 687 error = ENOEXEC; 688 goto bad; 689 } 690 interp = PNBUF_GET(); 691 interp[0] = '\0'; 692 if ((error = exec_read_from(l, epp->ep_vp, 693 pp->p_offset, interp, pp->p_filesz)) != 0) 694 goto bad; 695 break; 696 } 697 } 698 699 /* 700 * On the same architecture, we may be emulating different systems. 701 * See which one will accept this executable. 702 * 703 * Probe functions would normally see if the interpreter (if any) 704 * exists. Emulation packages may possibly replace the interpreter in 705 * interp[] with a changed path (/emul/xxx/<path>). 706 */ 707 pos = ELFDEFNNAME(NO_ADDR); 708 if (epp->ep_esch->u.elf_probe_func) { 709 vaddr_t startp = (vaddr_t)pos; 710 711 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 712 &startp); 713 if (error) 714 goto bad; 715 pos = (Elf_Addr)startp; 716 } 717 718 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 719 p->p_pax = 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 error = ENOEXEC; 745 goto bad; 746 } 747 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 748 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 749 750 /* 751 * Decide whether it's text or data by looking 752 * at the entry point. 753 */ 754 if (eh->e_entry >= addr && 755 eh->e_entry < (addr + size)) { 756 epp->ep_taddr = addr; 757 epp->ep_tsize = size; 758 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 759 epp->ep_daddr = addr; 760 epp->ep_dsize = size; 761 } 762 } else { 763 epp->ep_daddr = addr; 764 epp->ep_dsize = size; 765 } 766 break; 767 768 case PT_SHLIB: 769 /* SCO has these sections. */ 770 case PT_INTERP: 771 /* Already did this one. */ 772 case PT_DYNAMIC: 773 break; 774 case PT_NOTE: 775 break; 776 case PT_PHDR: 777 /* Note address of program headers (in text segment) */ 778 phdr = pp->p_vaddr; 779 break; 780 781 default: 782 /* 783 * Not fatal; we don't need to understand everything. 784 */ 785 break; 786 } 787 } 788 789 /* 790 * Check if we found a dynamically linked binary and arrange to load 791 * its interpreter 792 */ 793 if (interp) { 794 struct elf_args *ap; 795 int j = epp->ep_vmcmds.evs_used; 796 u_long interp_offset; 797 798 MALLOC(ap, struct elf_args *, sizeof(struct elf_args), 799 M_TEMP, M_WAITOK); 800 if ((error = elf_load_file(l, epp, interp, 801 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 802 FREE(ap, M_TEMP); 803 goto bad; 804 } 805 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 806 epp->ep_entry = ap->arg_interp + interp_offset; 807 ap->arg_phaddr = phdr; 808 809 ap->arg_phentsize = eh->e_phentsize; 810 ap->arg_phnum = eh->e_phnum; 811 ap->arg_entry = eh->e_entry; 812 813 epp->ep_emul_arg = ap; 814 815 PNBUF_PUT(interp); 816 } else 817 epp->ep_entry = eh->e_entry; 818 819 #ifdef ELF_MAP_PAGE_ZERO 820 /* Dell SVR4 maps page zero, yeuch! */ 821 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 822 epp->ep_vp, 0, VM_PROT_READ); 823 #endif 824 kmem_free(ph, phsize); 825 return (*epp->ep_esch->es_setup_stack)(l, epp); 826 827 bad: 828 if (interp) 829 PNBUF_PUT(interp); 830 kmem_free(ph, phsize); 831 kill_vmcmds(&epp->ep_vmcmds); 832 return error; 833 } 834 835 int 836 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 837 Elf_Ehdr *eh) 838 { 839 size_t i; 840 Elf_Phdr *ph; 841 size_t phsize; 842 int error; 843 int isnetbsd = 0; 844 char *ndata; 845 846 epp->ep_pax_flags = 0; 847 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 848 return ENOEXEC; 849 850 phsize = eh->e_phnum * sizeof(Elf_Phdr); 851 ph = kmem_alloc(phsize, KM_SLEEP); 852 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 853 if (error) 854 goto out; 855 856 for (i = 0; i < eh->e_phnum; i++) { 857 Elf_Phdr *ephp = &ph[i]; 858 Elf_Nhdr *np; 859 860 if (ephp->p_type != PT_NOTE || 861 ephp->p_filesz > 1024 || 862 ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 863 continue; 864 865 np = kmem_alloc(ephp->p_filesz, KM_SLEEP); 866 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, 867 ephp->p_filesz); 868 if (error) 869 goto next; 870 871 ndata = (char *)(np + 1); 872 switch (np->n_type) { 873 case ELF_NOTE_TYPE_NETBSD_TAG: 874 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 875 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 876 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 877 ELF_NOTE_NETBSD_NAMESZ)) 878 goto next; 879 isnetbsd = 1; 880 break; 881 882 case ELF_NOTE_TYPE_PAX_TAG: 883 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 884 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 885 memcmp(ndata, ELF_NOTE_PAX_NAME, 886 ELF_NOTE_PAX_NAMESZ)) 887 goto next; 888 (void)memcpy(&epp->ep_pax_flags, 889 ndata + ELF_NOTE_PAX_NAMESZ, 890 sizeof(epp->ep_pax_flags)); 891 break; 892 893 default: 894 break; 895 } 896 897 next: 898 kmem_free(np, ephp->p_filesz); 899 continue; 900 } 901 902 error = isnetbsd ? 0 : ENOEXEC; 903 out: 904 kmem_free(ph, phsize); 905 return error; 906 } 907 908 int 909 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 910 vaddr_t *pos) 911 { 912 int error; 913 914 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 915 return error; 916 #ifdef ELF_INTERP_NON_RELOCATABLE 917 *pos = ELF_LINK_ADDR; 918 #endif 919 return 0; 920 } 921