exec_elf.c revision 1.19
1 /* $NetBSD: exec_elf.c,v 1.19 2010/03/22 22:10:10 drochner 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 1.19 2010/03/22 22:10:10 drochner 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 static void 120 elf_placedynexec(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 121 Elf_Phdr *ph) 122 { 123 Elf_Addr align, offset; 124 int i; 125 126 for (align = i = 0; i < eh->e_phnum; i++) 127 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 128 align = ph[i].p_align; 129 130 #ifdef PAX_ASLR 131 if (pax_aslr_active(l)) { 132 size_t pax_align, l2, delta; 133 uint32_t r; 134 135 pax_align = align; 136 137 r = arc4random(); 138 139 if (pax_align == 0) 140 pax_align = PGSHIFT; 141 l2 = ilog2(pax_align); 142 delta = PAX_ASLR_DELTA(r, l2, PAX_ASLR_DELTA_EXEC_LEN); 143 offset = ELF_TRUNC(delta, pax_align) + PAGE_SIZE; 144 #ifdef PAX_ASLR_DEBUG 145 uprintf("r=0x%x l2=0x%zx PGSHIFT=0x%x Delta=0x%zx\n", r, l2, 146 PGSHIFT, delta); 147 uprintf("pax offset=0x%zx entry=0x%llx\n", 148 offset, (unsigned long long)eh->e_entry); 149 #endif /* PAX_ASLR_DEBUG */ 150 } else 151 #endif /* PAX_ASLR */ 152 offset = MAX(align, PAGE_SIZE); 153 154 for (i = 0; i < eh->e_phnum; i++) 155 ph[i].p_vaddr += offset; 156 eh->e_entry += offset; 157 } 158 159 /* 160 * Copy arguments onto the stack in the normal way, but add some 161 * extra information in case of dynamic binding. 162 */ 163 int 164 elf_copyargs(struct lwp *l, struct exec_package *pack, 165 struct ps_strings *arginfo, char **stackp, void *argp) 166 { 167 size_t len, vlen; 168 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 169 struct elf_args *ap; 170 int error; 171 172 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 173 return error; 174 175 a = ai; 176 execname = NULL; 177 178 /* 179 * Push extra arguments on the stack needed by dynamically 180 * linked binaries 181 */ 182 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 183 struct vattr *vap = pack->ep_vap; 184 185 a->a_type = AT_PHDR; 186 a->a_v = ap->arg_phaddr; 187 a++; 188 189 a->a_type = AT_PHENT; 190 a->a_v = ap->arg_phentsize; 191 a++; 192 193 a->a_type = AT_PHNUM; 194 a->a_v = ap->arg_phnum; 195 a++; 196 197 a->a_type = AT_PAGESZ; 198 a->a_v = PAGE_SIZE; 199 a++; 200 201 a->a_type = AT_BASE; 202 a->a_v = ap->arg_interp; 203 a++; 204 205 a->a_type = AT_FLAGS; 206 a->a_v = 0; 207 a++; 208 209 a->a_type = AT_ENTRY; 210 a->a_v = ap->arg_entry; 211 a++; 212 213 a->a_type = AT_EUID; 214 if (vap->va_mode & S_ISUID) 215 a->a_v = vap->va_uid; 216 else 217 a->a_v = kauth_cred_geteuid(l->l_cred); 218 a++; 219 220 a->a_type = AT_RUID; 221 a->a_v = kauth_cred_getuid(l->l_cred); 222 a++; 223 224 a->a_type = AT_EGID; 225 if (vap->va_mode & S_ISGID) 226 a->a_v = vap->va_gid; 227 else 228 a->a_v = kauth_cred_getegid(l->l_cred); 229 a++; 230 231 a->a_type = AT_RGID; 232 a->a_v = kauth_cred_getgid(l->l_cred); 233 a++; 234 235 if (pack->ep_path) { 236 execname = a; 237 a->a_type = AT_SUN_EXECNAME; 238 a++; 239 } 240 241 free(ap, M_TEMP); 242 pack->ep_emul_arg = NULL; 243 } 244 245 a->a_type = AT_NULL; 246 a->a_v = 0; 247 a++; 248 249 vlen = (a - ai) * sizeof(AuxInfo); 250 251 if (execname) { 252 char *path = pack->ep_path; 253 execname->a_v = (uintptr_t)(*stackp + vlen); 254 len = strlen(path) + 1; 255 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 256 return error; 257 len = ALIGN(len); 258 } else 259 len = 0; 260 261 if ((error = copyout(ai, *stackp, vlen)) != 0) 262 return error; 263 *stackp += vlen + len; 264 265 return 0; 266 } 267 268 /* 269 * elf_check_header(): 270 * 271 * Check header for validity; return 0 of ok ENOEXEC if error 272 */ 273 int 274 elf_check_header(Elf_Ehdr *eh, int type) 275 { 276 277 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 278 eh->e_ident[EI_CLASS] != ELFCLASS) 279 return ENOEXEC; 280 281 switch (eh->e_machine) { 282 283 ELFDEFNNAME(MACHDEP_ID_CASES) 284 285 default: 286 return ENOEXEC; 287 } 288 289 if (ELF_EHDR_FLAGS_OK(eh) == 0) 290 return ENOEXEC; 291 292 if (eh->e_type != type) 293 return ENOEXEC; 294 295 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 296 return ENOEXEC; 297 298 return 0; 299 } 300 301 /* 302 * elf_load_psection(): 303 * 304 * Load a psection at the appropriate address 305 */ 306 void 307 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 308 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 309 { 310 u_long msize, psize, rm, rf; 311 long diff, offset; 312 313 /* 314 * If the user specified an address, then we load there. 315 */ 316 if (*addr == ELFDEFNNAME(NO_ADDR)) 317 *addr = ph->p_vaddr; 318 319 if (ph->p_align > 1) { 320 /* 321 * Make sure we are virtually aligned as we are supposed to be. 322 */ 323 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 324 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 325 /* 326 * But make sure to not map any pages before the start of the 327 * psection by limiting the difference to within a page. 328 */ 329 diff &= PAGE_MASK; 330 } else 331 diff = 0; 332 333 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 334 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 335 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 336 337 /* 338 * Adjust everything so it all starts on a page boundary. 339 */ 340 *addr -= diff; 341 offset = ph->p_offset - diff; 342 *size = ph->p_filesz + diff; 343 msize = ph->p_memsz + diff; 344 345 if (ph->p_align >= PAGE_SIZE) { 346 if ((ph->p_flags & PF_W) != 0) { 347 /* 348 * Because the pagedvn pager can't handle zero fill 349 * of the last data page if it's not page aligned we 350 * map the last page readvn. 351 */ 352 psize = trunc_page(*size); 353 } else { 354 psize = round_page(*size); 355 } 356 } else { 357 psize = *size; 358 } 359 360 if (psize > 0) { 361 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 362 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 363 offset, *prot, flags); 364 flags &= VMCMD_RELATIVE; 365 } 366 if (psize < *size) { 367 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 368 *addr + psize, vp, offset + psize, *prot, flags); 369 } 370 371 /* 372 * Check if we need to extend the size of the segment (does 373 * bss extend page the next page boundary)? 374 */ 375 rm = round_page(*addr + msize); 376 rf = round_page(*addr + *size); 377 378 if (rm != rf) { 379 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 380 0, *prot, flags & VMCMD_RELATIVE); 381 *size = msize; 382 } 383 } 384 385 /* 386 * elf_load_file(): 387 * 388 * Load a file (interpreter/library) pointed to by path 389 * [stolen from coff_load_shlib()]. Made slightly generic 390 * so it might be used externally. 391 */ 392 int 393 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 394 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 395 Elf_Addr *last) 396 { 397 int error, i; 398 struct vnode *vp; 399 struct vattr attr; 400 Elf_Ehdr eh; 401 Elf_Phdr *ph = NULL; 402 const Elf_Phdr *ph0; 403 const Elf_Phdr *base_ph; 404 const Elf_Phdr *last_ph; 405 u_long phsize; 406 Elf_Addr addr = *last; 407 struct proc *p; 408 409 p = l->l_proc; 410 411 /* 412 * 1. open file 413 * 2. read filehdr 414 * 3. map text, data, and bss out of it using VM_* 415 */ 416 vp = epp->ep_interp; 417 if (vp == NULL) { 418 error = emul_find_interp(l, epp, path); 419 if (error != 0) 420 return error; 421 vp = epp->ep_interp; 422 } 423 /* We'll tidy this ourselves - otherwise we have locking issues */ 424 epp->ep_interp = NULL; 425 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 426 427 /* 428 * Similarly, if it's not marked as executable, or it's not a regular 429 * file, we don't allow it to be used. 430 */ 431 if (vp->v_type != VREG) { 432 error = EACCES; 433 goto badunlock; 434 } 435 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 436 goto badunlock; 437 438 /* get attributes */ 439 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 440 goto badunlock; 441 442 /* 443 * Check mount point. Though we're not trying to exec this binary, 444 * we will be executing code from it, so if the mount point 445 * disallows execution or set-id-ness, we punt or kill the set-id. 446 */ 447 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 448 error = EACCES; 449 goto badunlock; 450 } 451 if (vp->v_mount->mnt_flag & MNT_NOSUID) 452 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 453 454 #ifdef notyet /* XXX cgd 960926 */ 455 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 456 #endif 457 458 error = vn_marktext(vp); 459 if (error) 460 goto badunlock; 461 462 VOP_UNLOCK(vp, 0); 463 464 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 465 goto bad; 466 467 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 468 goto bad; 469 470 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 471 error = ENOEXEC; 472 goto bad; 473 } 474 475 phsize = eh.e_phnum * sizeof(Elf_Phdr); 476 ph = kmem_alloc(phsize, KM_SLEEP); 477 478 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 479 goto bad; 480 481 #ifdef ELF_INTERP_NON_RELOCATABLE 482 /* 483 * Evil hack: Only MIPS should be non-relocatable, and the 484 * psections should have a high address (typically 0x5ffe0000). 485 * If it's now relocatable, it should be linked at 0 and the 486 * psections should have zeros in the upper part of the address. 487 * Otherwise, force the load at the linked address. 488 */ 489 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 490 *last = ELFDEFNNAME(NO_ADDR); 491 #endif 492 493 /* 494 * If no position to load the interpreter was set by a probe 495 * function, pick the same address that a non-fixed mmap(0, ..) 496 * would (i.e. something safely out of the way). 497 */ 498 if (*last == ELFDEFNNAME(NO_ADDR)) { 499 u_long limit = 0; 500 /* 501 * Find the start and ending addresses of the psections to 502 * be loaded. This will give us the size. 503 */ 504 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 505 i++, ph0++) { 506 if (ph0->p_type == PT_LOAD) { 507 u_long psize = ph0->p_vaddr + ph0->p_memsz; 508 if (base_ph == NULL) 509 base_ph = ph0; 510 if (psize > limit) 511 limit = psize; 512 } 513 } 514 515 if (base_ph == NULL) { 516 error = ENOEXEC; 517 goto bad; 518 } 519 520 /* 521 * Now compute the size and load address. 522 */ 523 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 524 epp->ep_daddr, 525 round_page(limit) - trunc_page(base_ph->p_vaddr)); 526 } else 527 addr = *last; /* may be ELF_LINK_ADDR */ 528 529 /* 530 * Load all the necessary sections 531 */ 532 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 533 i < eh.e_phnum; i++, ph0++) { 534 switch (ph0->p_type) { 535 case PT_LOAD: { 536 u_long size; 537 int prot = 0; 538 int flags; 539 540 if (base_ph == NULL) { 541 /* 542 * First encountered psection is always the 543 * base psection. Make sure it's aligned 544 * properly (align down for topdown and align 545 * upwards for not topdown). 546 */ 547 base_ph = ph0; 548 flags = VMCMD_BASE; 549 if (addr == ELF_LINK_ADDR) 550 addr = ph0->p_vaddr; 551 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 552 addr = ELF_TRUNC(addr, ph0->p_align); 553 else 554 addr = ELF_ROUND(addr, ph0->p_align); 555 } else { 556 u_long limit = round_page(last_ph->p_vaddr 557 + last_ph->p_memsz); 558 u_long base = trunc_page(ph0->p_vaddr); 559 560 /* 561 * If there is a gap in between the psections, 562 * map it as inaccessible so nothing else 563 * mmap'ed will be placed there. 564 */ 565 if (limit != base) { 566 NEW_VMCMD2(vcset, vmcmd_map_zero, 567 base - limit, 568 limit - base_ph->p_vaddr, NULLVP, 569 0, VM_PROT_NONE, VMCMD_RELATIVE); 570 } 571 572 addr = ph0->p_vaddr - base_ph->p_vaddr; 573 flags = VMCMD_RELATIVE; 574 } 575 last_ph = ph0; 576 elf_load_psection(vcset, vp, &ph[i], &addr, 577 &size, &prot, flags); 578 /* 579 * If entry is within this psection then this 580 * must contain the .text section. *entryoff is 581 * relative to the base psection. 582 */ 583 if (eh.e_entry >= ph0->p_vaddr && 584 eh.e_entry < (ph0->p_vaddr + size)) { 585 *entryoff = eh.e_entry - base_ph->p_vaddr; 586 } 587 addr += size; 588 break; 589 } 590 591 case PT_DYNAMIC: 592 case PT_PHDR: 593 break; 594 595 case PT_NOTE: 596 break; 597 598 default: 599 break; 600 } 601 } 602 603 kmem_free(ph, phsize); 604 /* 605 * This value is ignored if TOPDOWN. 606 */ 607 *last = addr; 608 vrele(vp); 609 return 0; 610 611 badunlock: 612 VOP_UNLOCK(vp, 0); 613 614 bad: 615 if (ph != NULL) 616 kmem_free(ph, phsize); 617 #ifdef notyet /* XXX cgd 960926 */ 618 (maybe) VOP_CLOSE it 619 #endif 620 vrele(vp); 621 return error; 622 } 623 624 /* 625 * exec_elf_makecmds(): Prepare an Elf binary's exec package 626 * 627 * First, set of the various offsets/lengths in the exec package. 628 * 629 * Then, mark the text image busy (so it can be demand paged) or error 630 * out if this is not possible. Finally, set up vmcmds for the 631 * text, data, bss, and stack segments. 632 */ 633 int 634 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 635 { 636 Elf_Ehdr *eh = epp->ep_hdr; 637 Elf_Phdr *ph, *pp; 638 Elf_Addr phdr = 0, pos = 0; 639 int error, i, nload; 640 char *interp = NULL; 641 u_long phsize; 642 struct proc *p; 643 bool is_dyn; 644 645 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 646 return ENOEXEC; 647 648 is_dyn = elf_check_header(eh, ET_DYN) == 0; 649 /* 650 * XXX allow for executing shared objects. It seems silly 651 * but other ELF-based systems allow it as well. 652 */ 653 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 654 return ENOEXEC; 655 656 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 657 return ENOEXEC; 658 659 error = vn_marktext(epp->ep_vp); 660 if (error) 661 return error; 662 663 /* 664 * Allocate space to hold all the program headers, and read them 665 * from the file 666 */ 667 p = l->l_proc; 668 phsize = eh->e_phnum * sizeof(Elf_Phdr); 669 ph = kmem_alloc(phsize, KM_SLEEP); 670 671 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 672 0) 673 goto bad; 674 675 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 676 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 677 678 for (i = 0; i < eh->e_phnum; i++) { 679 pp = &ph[i]; 680 if (pp->p_type == PT_INTERP) { 681 if (pp->p_filesz >= MAXPATHLEN) { 682 error = ENOEXEC; 683 goto bad; 684 } 685 interp = PNBUF_GET(); 686 interp[0] = '\0'; 687 if ((error = exec_read_from(l, epp->ep_vp, 688 pp->p_offset, interp, pp->p_filesz)) != 0) 689 goto bad; 690 break; 691 } 692 } 693 694 /* 695 * On the same architecture, we may be emulating different systems. 696 * See which one will accept this executable. 697 * 698 * Probe functions would normally see if the interpreter (if any) 699 * exists. Emulation packages may possibly replace the interpreter in 700 * interp[] with a changed path (/emul/xxx/<path>). 701 */ 702 pos = ELFDEFNNAME(NO_ADDR); 703 if (epp->ep_esch->u.elf_probe_func) { 704 vaddr_t startp = (vaddr_t)pos; 705 706 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 707 &startp); 708 if (error) 709 goto bad; 710 pos = (Elf_Addr)startp; 711 } 712 713 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 714 p->p_pax = epp->ep_pax_flags; 715 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 716 717 if (is_dyn) 718 elf_placedynexec(l, epp, eh, ph); 719 720 /* 721 * Load all the necessary sections 722 */ 723 for (i = nload = 0; i < eh->e_phnum; i++) { 724 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 725 u_long size = 0; 726 int prot = 0; 727 728 pp = &ph[i]; 729 730 switch (ph[i].p_type) { 731 case PT_LOAD: 732 /* 733 * XXX 734 * Can handle only 2 sections: text and data 735 */ 736 if (nload++ == 2) { 737 error = ENOEXEC; 738 goto bad; 739 } 740 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 741 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 742 743 /* 744 * Decide whether it's text or data by looking 745 * at the entry point. 746 */ 747 if (eh->e_entry >= addr && 748 eh->e_entry < (addr + size)) { 749 epp->ep_taddr = addr; 750 epp->ep_tsize = size; 751 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 752 epp->ep_daddr = addr; 753 epp->ep_dsize = size; 754 } 755 } else { 756 epp->ep_daddr = addr; 757 epp->ep_dsize = size; 758 } 759 break; 760 761 case PT_SHLIB: 762 /* SCO has these sections. */ 763 case PT_INTERP: 764 /* Already did this one. */ 765 case PT_DYNAMIC: 766 break; 767 case PT_NOTE: 768 break; 769 case PT_PHDR: 770 /* Note address of program headers (in text segment) */ 771 phdr = pp->p_vaddr; 772 break; 773 774 default: 775 /* 776 * Not fatal; we don't need to understand everything. 777 */ 778 break; 779 } 780 } 781 782 /* 783 * Check if we found a dynamically linked binary and arrange to load 784 * its interpreter 785 */ 786 if (interp) { 787 struct elf_args *ap; 788 int j = epp->ep_vmcmds.evs_used; 789 u_long interp_offset; 790 791 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 792 M_TEMP, M_WAITOK); 793 if ((error = elf_load_file(l, epp, interp, 794 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 795 free(ap, M_TEMP); 796 goto bad; 797 } 798 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 799 epp->ep_entry = ap->arg_interp + interp_offset; 800 ap->arg_phaddr = phdr; 801 802 ap->arg_phentsize = eh->e_phentsize; 803 ap->arg_phnum = eh->e_phnum; 804 ap->arg_entry = eh->e_entry; 805 806 epp->ep_emul_arg = ap; 807 808 PNBUF_PUT(interp); 809 } else 810 epp->ep_entry = eh->e_entry; 811 812 #ifdef ELF_MAP_PAGE_ZERO 813 /* Dell SVR4 maps page zero, yeuch! */ 814 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 815 epp->ep_vp, 0, VM_PROT_READ); 816 #endif 817 kmem_free(ph, phsize); 818 return (*epp->ep_esch->es_setup_stack)(l, epp); 819 820 bad: 821 if (interp) 822 PNBUF_PUT(interp); 823 kmem_free(ph, phsize); 824 kill_vmcmds(&epp->ep_vmcmds); 825 return error; 826 } 827 828 int 829 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 830 Elf_Ehdr *eh) 831 { 832 size_t i; 833 Elf_Shdr *sh; 834 Elf_Nhdr *np; 835 size_t shsize; 836 int error; 837 int isnetbsd = 0; 838 char *ndata; 839 840 epp->ep_pax_flags = 0; 841 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 842 return ENOEXEC; 843 844 shsize = eh->e_shnum * sizeof(Elf_Shdr); 845 sh = kmem_alloc(shsize, KM_SLEEP); 846 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 847 if (error) 848 goto out; 849 850 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 851 for (i = 0; i < eh->e_shnum; i++) { 852 Elf_Shdr *shp = &sh[i]; 853 854 if (shp->sh_type != SHT_NOTE || 855 shp->sh_size > MAXNOTESIZE || 856 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 857 continue; 858 859 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 860 shp->sh_size); 861 if (error) 862 continue; 863 864 ndata = (char *)(np + 1); 865 switch (np->n_type) { 866 case ELF_NOTE_TYPE_NETBSD_TAG: 867 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 868 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 869 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 870 ELF_NOTE_NETBSD_NAMESZ)) 871 goto bad; 872 isnetbsd = 1; 873 break; 874 875 case ELF_NOTE_TYPE_PAX_TAG: 876 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 877 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 878 memcmp(ndata, ELF_NOTE_PAX_NAME, 879 ELF_NOTE_PAX_NAMESZ)) { 880 bad: 881 #ifdef DIAGNOSTIC 882 printf("%s: bad tag %d: " 883 "[%d %d, %d %d, %*.*s %*.*s]\n", 884 epp->ep_name, 885 np->n_type, 886 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 887 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 888 ELF_NOTE_PAX_NAMESZ, 889 ELF_NOTE_PAX_NAMESZ, 890 ndata, 891 ELF_NOTE_PAX_NAMESZ, 892 ELF_NOTE_PAX_NAMESZ, 893 ELF_NOTE_PAX_NAME); 894 #endif 895 continue; 896 } 897 (void)memcpy(&epp->ep_pax_flags, 898 ndata + ELF_NOTE_PAX_NAMESZ, 899 sizeof(epp->ep_pax_flags)); 900 break; 901 902 default: 903 #ifdef DIAGNOSTIC 904 printf("%s: unknown note type %d\n", epp->ep_name, 905 np->n_type); 906 #endif 907 break; 908 } 909 } 910 kmem_free(np, MAXNOTESIZE); 911 912 error = isnetbsd ? 0 : ENOEXEC; 913 out: 914 kmem_free(sh, shsize); 915 return error; 916 } 917 918 int 919 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 920 vaddr_t *pos) 921 { 922 int error; 923 924 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 925 return error; 926 #ifdef ELF_MD_PROBE_FUNC 927 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 928 return error; 929 #elif defined(ELF_INTERP_NON_RELOCATABLE) 930 *pos = ELF_LINK_ADDR; 931 #endif 932 return 0; 933 } 934
Indexes created Mon Sep 22 05:09:51 GMT 2025