exec_elf.c revision 1.17
1 /* $NetBSD: exec_elf.c,v 1.17 2010/03/20 01:47:12 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_elf.c,v 1.17 2010/03/20 01:47:12 christos Exp $"); 61 62 #ifdef _KERNEL_OPT 63 #include "opt_pax.h" 64 #endif /* _KERNEL_OPT */ 65 66 #include <sys/param.h> 67 #include <sys/proc.h> 68 #include <sys/malloc.h> 69 #include <sys/kmem.h> 70 #include <sys/namei.h> 71 #include <sys/vnode.h> 72 #include <sys/exec.h> 73 #include <sys/exec_elf.h> 74 #include <sys/syscall.h> 75 #include <sys/signalvar.h> 76 #include <sys/mount.h> 77 #include <sys/stat.h> 78 #include <sys/kauth.h> 79 #include <sys/bitops.h> 80 81 #include <sys/cpu.h> 82 #include <machine/reg.h> 83 84 #include <compat/common/compat_util.h> 85 86 #include <sys/pax.h> 87 88 extern struct emul emul_netbsd; 89 90 #define elf_check_header ELFNAME(check_header) 91 #define elf_copyargs ELFNAME(copyargs) 92 #define elf_load_file ELFNAME(load_file) 93 #define elf_load_psection ELFNAME(load_psection) 94 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 95 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 96 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 97 #define coredump ELFNAMEEND(coredump) 98 99 int elf_load_file(struct lwp *, struct exec_package *, char *, 100 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); 101 void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, 102 const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); 103 104 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 105 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 106 vaddr_t *); 107 108 /* round up and down to page boundaries. */ 109 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 110 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 111 112 /* 113 * Arbitrary limits to avoid DoS for excessive memory allocation. 114 */ 115 #define MAXPHNUM 128 116 #define MAXSHNUM 32768 117 #define MAXNOTESIZE 1024 118 119 /* 120 * We don't move this code in kern_pax.c because it is compiled twice. 121 */ 122 static void 123 elf_placedynexec(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 124 Elf_Phdr *ph) 125 { 126 size_t offset, i; 127 128 #ifdef PAX_ASLR 129 if (pax_aslr_active(l)) { 130 size_t pax_align, l2, delta; 131 uint32_t r; 132 133 /* 134 * find align XXX: not all sections might have the same 135 * alignment 136 */ 137 for (pax_align = i = 0; i < eh->e_phnum; i++) 138 if (ph[i].p_type == PT_LOAD) { 139 pax_align = ph[i].p_align; 140 break; 141 } 142 143 r = arc4random(); 144 145 if (pax_align == 0) 146 pax_align = PGSHIFT; 147 l2 = ilog2(pax_align); 148 delta = PAX_ASLR_DELTA(r, l2, PAX_ASLR_DELTA_EXEC_LEN); 149 uprintf("r=0x%x a=0x%x p=0x%x Delta=0x%lx\n", r, l2, PGSHIFT, 150 delta); 151 offset = ELF_TRUNC(delta, pax_align) + PAGE_SIZE; 152 #ifdef PAX_ASLR_DEBUG 153 uprintf("pax offset=0x%zx entry=0x%llx\n", 154 offset, (unsigned long long)eh->e_entry); 155 #endif /* PAX_ASLR_DEBUG */ 156 } else 157 #endif /* PAX_ASLR */ 158 offset = PAGE_SIZE; 159 160 for (i = 0; i < eh->e_phnum; i++) 161 ph[i].p_vaddr += pax_offset; 162 eh->e_entry += offset; 163 } 164 165 /* 166 * Copy arguments onto the stack in the normal way, but add some 167 * extra information in case of dynamic binding. 168 */ 169 int 170 elf_copyargs(struct lwp *l, struct exec_package *pack, 171 struct ps_strings *arginfo, char **stackp, void *argp) 172 { 173 size_t len, vlen; 174 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 175 struct elf_args *ap; 176 int error; 177 178 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 179 return error; 180 181 a = ai; 182 execname = NULL; 183 184 /* 185 * Push extra arguments on the stack needed by dynamically 186 * linked binaries 187 */ 188 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 189 struct vattr *vap = pack->ep_vap; 190 191 a->a_type = AT_PHDR; 192 a->a_v = ap->arg_phaddr; 193 a++; 194 195 a->a_type = AT_PHENT; 196 a->a_v = ap->arg_phentsize; 197 a++; 198 199 a->a_type = AT_PHNUM; 200 a->a_v = ap->arg_phnum; 201 a++; 202 203 a->a_type = AT_PAGESZ; 204 a->a_v = PAGE_SIZE; 205 a++; 206 207 a->a_type = AT_BASE; 208 a->a_v = ap->arg_interp; 209 a++; 210 211 a->a_type = AT_FLAGS; 212 a->a_v = 0; 213 a++; 214 215 a->a_type = AT_ENTRY; 216 a->a_v = ap->arg_entry; 217 a++; 218 219 a->a_type = AT_EUID; 220 if (vap->va_mode & S_ISUID) 221 a->a_v = vap->va_uid; 222 else 223 a->a_v = kauth_cred_geteuid(l->l_cred); 224 a++; 225 226 a->a_type = AT_RUID; 227 a->a_v = kauth_cred_getuid(l->l_cred); 228 a++; 229 230 a->a_type = AT_EGID; 231 if (vap->va_mode & S_ISGID) 232 a->a_v = vap->va_gid; 233 else 234 a->a_v = kauth_cred_getegid(l->l_cred); 235 a++; 236 237 a->a_type = AT_RGID; 238 a->a_v = kauth_cred_getgid(l->l_cred); 239 a++; 240 241 if (pack->ep_path) { 242 execname = a; 243 a->a_type = AT_SUN_EXECNAME; 244 a++; 245 } 246 247 free(ap, M_TEMP); 248 pack->ep_emul_arg = NULL; 249 } 250 251 a->a_type = AT_NULL; 252 a->a_v = 0; 253 a++; 254 255 vlen = (a - ai) * sizeof(AuxInfo); 256 257 if (execname) { 258 char *path = pack->ep_path; 259 execname->a_v = (uintptr_t)(*stackp + vlen); 260 len = strlen(path) + 1; 261 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 262 return error; 263 len = ALIGN(len); 264 } else 265 len = 0; 266 267 if ((error = copyout(ai, *stackp, vlen)) != 0) 268 return error; 269 *stackp += vlen + len; 270 271 return 0; 272 } 273 274 /* 275 * elf_check_header(): 276 * 277 * Check header for validity; return 0 of ok ENOEXEC if error 278 */ 279 int 280 elf_check_header(Elf_Ehdr *eh, int type) 281 { 282 283 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 284 eh->e_ident[EI_CLASS] != ELFCLASS) 285 return ENOEXEC; 286 287 switch (eh->e_machine) { 288 289 ELFDEFNNAME(MACHDEP_ID_CASES) 290 291 default: 292 return ENOEXEC; 293 } 294 295 if (ELF_EHDR_FLAGS_OK(eh) == 0) 296 return ENOEXEC; 297 298 if (eh->e_type != type) 299 return ENOEXEC; 300 301 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 302 return ENOEXEC; 303 304 return 0; 305 } 306 307 /* 308 * elf_load_psection(): 309 * 310 * Load a psection at the appropriate address 311 */ 312 void 313 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 314 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 315 { 316 u_long msize, psize, rm, rf; 317 long diff, offset; 318 319 /* 320 * If the user specified an address, then we load there. 321 */ 322 if (*addr == ELFDEFNNAME(NO_ADDR)) 323 *addr = ph->p_vaddr; 324 325 if (ph->p_align > 1) { 326 /* 327 * Make sure we are virtually aligned as we are supposed to be. 328 */ 329 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 330 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 331 /* 332 * But make sure to not map any pages before the start of the 333 * psection by limiting the difference to within a page. 334 */ 335 diff &= PAGE_MASK; 336 } else 337 diff = 0; 338 339 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 340 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 341 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 342 343 /* 344 * Adjust everything so it all starts on a page boundary. 345 */ 346 *addr -= diff; 347 offset = ph->p_offset - diff; 348 *size = ph->p_filesz + diff; 349 msize = ph->p_memsz + diff; 350 351 if (ph->p_align >= PAGE_SIZE) { 352 if ((ph->p_flags & PF_W) != 0) { 353 /* 354 * Because the pagedvn pager can't handle zero fill 355 * of the last data page if it's not page aligned we 356 * map the last page readvn. 357 */ 358 psize = trunc_page(*size); 359 } else { 360 psize = round_page(*size); 361 } 362 } else { 363 psize = *size; 364 } 365 366 if (psize > 0) { 367 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 368 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 369 offset, *prot, flags); 370 flags &= VMCMD_RELATIVE; 371 } 372 if (psize < *size) { 373 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 374 *addr + psize, vp, offset + psize, *prot, flags); 375 } 376 377 /* 378 * Check if we need to extend the size of the segment (does 379 * bss extend page the next page boundary)? 380 */ 381 rm = round_page(*addr + msize); 382 rf = round_page(*addr + *size); 383 384 if (rm != rf) { 385 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 386 0, *prot, flags & VMCMD_RELATIVE); 387 *size = msize; 388 } 389 } 390 391 /* 392 * elf_load_file(): 393 * 394 * Load a file (interpreter/library) pointed to by path 395 * [stolen from coff_load_shlib()]. Made slightly generic 396 * so it might be used externally. 397 */ 398 int 399 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 400 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 401 Elf_Addr *last) 402 { 403 int error, i; 404 struct vnode *vp; 405 struct vattr attr; 406 Elf_Ehdr eh; 407 Elf_Phdr *ph = NULL; 408 const Elf_Phdr *ph0; 409 const Elf_Phdr *base_ph; 410 const Elf_Phdr *last_ph; 411 u_long phsize; 412 Elf_Addr addr = *last; 413 struct proc *p; 414 415 p = l->l_proc; 416 417 /* 418 * 1. open file 419 * 2. read filehdr 420 * 3. map text, data, and bss out of it using VM_* 421 */ 422 vp = epp->ep_interp; 423 if (vp == NULL) { 424 error = emul_find_interp(l, epp, path); 425 if (error != 0) 426 return error; 427 vp = epp->ep_interp; 428 } 429 /* We'll tidy this ourselves - otherwise we have locking issues */ 430 epp->ep_interp = NULL; 431 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 432 433 /* 434 * Similarly, if it's not marked as executable, or it's not a regular 435 * file, we don't allow it to be used. 436 */ 437 if (vp->v_type != VREG) { 438 error = EACCES; 439 goto badunlock; 440 } 441 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 442 goto badunlock; 443 444 /* get attributes */ 445 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 446 goto badunlock; 447 448 /* 449 * Check mount point. Though we're not trying to exec this binary, 450 * we will be executing code from it, so if the mount point 451 * disallows execution or set-id-ness, we punt or kill the set-id. 452 */ 453 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 454 error = EACCES; 455 goto badunlock; 456 } 457 if (vp->v_mount->mnt_flag & MNT_NOSUID) 458 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 459 460 #ifdef notyet /* XXX cgd 960926 */ 461 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 462 #endif 463 464 error = vn_marktext(vp); 465 if (error) 466 goto badunlock; 467 468 VOP_UNLOCK(vp, 0); 469 470 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 471 goto bad; 472 473 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 474 goto bad; 475 476 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 477 error = ENOEXEC; 478 goto bad; 479 } 480 481 phsize = eh.e_phnum * sizeof(Elf_Phdr); 482 ph = kmem_alloc(phsize, KM_SLEEP); 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 kmem_free(ph, phsize); 610 /* 611 * This value is ignored if TOPDOWN. 612 */ 613 *last = addr; 614 vrele(vp); 615 return 0; 616 617 badunlock: 618 VOP_UNLOCK(vp, 0); 619 620 bad: 621 if (ph != NULL) 622 kmem_free(ph, phsize); 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 */ 639 int 640 exec_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 || eh->e_phnum == 0) 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 = kmem_alloc(phsize, KM_SLEEP); 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 error = ENOEXEC; 689 goto bad; 690 } 691 interp = PNBUF_GET(); 692 interp[0] = '\0'; 693 if ((error = exec_read_from(l, epp->ep_vp, 694 pp->p_offset, interp, pp->p_filesz)) != 0) 695 goto bad; 696 break; 697 } 698 } 699 700 /* 701 * On the same architecture, we may be emulating different systems. 702 * See which one will accept this executable. 703 * 704 * Probe functions would normally see if the interpreter (if any) 705 * exists. Emulation packages may possibly replace the interpreter in 706 * interp[] with a changed path (/emul/xxx/<path>). 707 */ 708 pos = ELFDEFNNAME(NO_ADDR); 709 if (epp->ep_esch->u.elf_probe_func) { 710 vaddr_t startp = (vaddr_t)pos; 711 712 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 713 &startp); 714 if (error) 715 goto bad; 716 pos = (Elf_Addr)startp; 717 } 718 719 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 720 p->p_pax = epp->ep_pax_flags; 721 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 722 723 if (is_dyn) 724 elf_placedynexec(l, epp, eh, ph); 725 726 /* 727 * Load all the necessary sections 728 */ 729 for (i = nload = 0; i < eh->e_phnum; i++) { 730 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 731 u_long size = 0; 732 int prot = 0; 733 734 pp = &ph[i]; 735 736 switch (ph[i].p_type) { 737 case PT_LOAD: 738 /* 739 * XXX 740 * Can handle only 2 sections: text and data 741 */ 742 if (nload++ == 2) { 743 error = ENOEXEC; 744 goto bad; 745 } 746 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 747 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 748 749 /* 750 * Decide whether it's text or data by looking 751 * at the entry point. 752 */ 753 if (eh->e_entry >= addr && 754 eh->e_entry < (addr + size)) { 755 epp->ep_taddr = addr; 756 epp->ep_tsize = size; 757 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 758 epp->ep_daddr = addr; 759 epp->ep_dsize = size; 760 } 761 } else { 762 epp->ep_daddr = addr; 763 epp->ep_dsize = size; 764 } 765 break; 766 767 case PT_SHLIB: 768 /* SCO has these sections. */ 769 case PT_INTERP: 770 /* Already did this one. */ 771 case PT_DYNAMIC: 772 break; 773 case PT_NOTE: 774 break; 775 case PT_PHDR: 776 /* Note address of program headers (in text segment) */ 777 phdr = pp->p_vaddr; 778 break; 779 780 default: 781 /* 782 * Not fatal; we don't need to understand everything. 783 */ 784 break; 785 } 786 } 787 788 /* 789 * Check if we found a dynamically linked binary and arrange to load 790 * its interpreter 791 */ 792 if (interp) { 793 struct elf_args *ap; 794 int j = epp->ep_vmcmds.evs_used; 795 u_long interp_offset; 796 797 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 798 M_TEMP, M_WAITOK); 799 if ((error = elf_load_file(l, epp, interp, 800 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 801 free(ap, M_TEMP); 802 goto bad; 803 } 804 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 805 epp->ep_entry = ap->arg_interp + interp_offset; 806 ap->arg_phaddr = phdr; 807 808 ap->arg_phentsize = eh->e_phentsize; 809 ap->arg_phnum = eh->e_phnum; 810 ap->arg_entry = eh->e_entry; 811 812 epp->ep_emul_arg = ap; 813 814 PNBUF_PUT(interp); 815 } else 816 epp->ep_entry = eh->e_entry; 817 818 #ifdef ELF_MAP_PAGE_ZERO 819 /* Dell SVR4 maps page zero, yeuch! */ 820 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 821 epp->ep_vp, 0, VM_PROT_READ); 822 #endif 823 kmem_free(ph, phsize); 824 return (*epp->ep_esch->es_setup_stack)(l, epp); 825 826 bad: 827 if (interp) 828 PNBUF_PUT(interp); 829 kmem_free(ph, phsize); 830 kill_vmcmds(&epp->ep_vmcmds); 831 return error; 832 } 833 834 int 835 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 836 Elf_Ehdr *eh) 837 { 838 size_t i; 839 Elf_Shdr *sh; 840 Elf_Nhdr *np; 841 size_t shsize; 842 int error; 843 int isnetbsd = 0; 844 char *ndata; 845 846 epp->ep_pax_flags = 0; 847 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 848 return ENOEXEC; 849 850 shsize = eh->e_shnum * sizeof(Elf_Shdr); 851 sh = kmem_alloc(shsize, KM_SLEEP); 852 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 853 if (error) 854 goto out; 855 856 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 857 for (i = 0; i < eh->e_shnum; i++) { 858 Elf_Shdr *shp = &sh[i]; 859 860 if (shp->sh_type != SHT_NOTE || 861 shp->sh_size > MAXNOTESIZE || 862 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 863 continue; 864 865 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 866 shp->sh_size); 867 if (error) 868 continue; 869 870 ndata = (char *)(np + 1); 871 switch (np->n_type) { 872 case ELF_NOTE_TYPE_NETBSD_TAG: 873 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 874 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 875 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 876 ELF_NOTE_NETBSD_NAMESZ)) 877 goto bad; 878 isnetbsd = 1; 879 break; 880 881 case ELF_NOTE_TYPE_PAX_TAG: 882 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 883 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 884 memcmp(ndata, ELF_NOTE_PAX_NAME, 885 ELF_NOTE_PAX_NAMESZ)) { 886 bad: 887 #ifdef DIAGNOSTIC 888 printf("%s: bad tag %d: " 889 "[%d %d, %d %d, %*.*s %*.*s]\n", 890 epp->ep_name, 891 np->n_type 892 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 893 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 894 ELF_NOTE_PAX_NAMESZ, 895 ELF_NOTE_PAX_NAMESZ, 896 ndata, 897 ELF_NOTE_PAX_NAMESZ, 898 ELF_NOTE_PAX_NAMESZ, 899 ELF_NOTE_PAX_NAME); 900 #endif 901 continue; 902 } 903 (void)memcpy(&epp->ep_pax_flags, 904 ndata + ELF_NOTE_PAX_NAMESZ, 905 sizeof(epp->ep_pax_flags)); 906 break; 907 908 default: 909 #ifdef DIAGNOSTIC 910 printf("%s: unknown note type %d\n", epp->ep_name, 911 np->n_type); 912 #endif 913 break; 914 } 915 } 916 kmem_free(np, MAXNOTESIZE); 917 918 error = isnetbsd ? 0 : ENOEXEC; 919 out: 920 kmem_free(sh, shsize); 921 return error; 922 } 923 924 int 925 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 926 vaddr_t *pos) 927 { 928 int error; 929 930 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 931 return error; 932 #ifdef ELF_MD_PROBE_FUNC 933 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 934 return error; 935 #elif defined(ELF_INTERP_NON_RELOCATABLE) 936 *pos = ELF_LINK_ADDR; 937 #endif 938 return 0; 939 } 940
Indexes created Sun Sep 21 20:09:37 GMT 2025