exec_elf.c revision 1.15
1 /* $NetBSD: exec_elf.c,v 1.15 2010/03/19 22:08:13 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 1.15 2010/03/19 22:08:13 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 #ifdef PAX_ASLR 120 /* 121 * We don't move this code in kern_pax.c because it is compiled twice. 122 */ 123 static void 124 pax_aslr_elf(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 125 Elf_Phdr *ph) 126 { 127 size_t pax_offset, i; 128 129 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 #ifdef PAX_ASLR_DEBUG 150 uprintf("r=0x%x a=0x%x p=0x%x Delta=0x%lx\n", r, l2, PGSHIFT, 151 delta); 152 #endif 153 pax_offset = ELF_TRUNC(delta, pax_align) + PAGE_SIZE; 154 } else 155 pax_offset = PAGE_SIZE; 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 PAX_ASLR_DEBUG 161 uprintf("pax offset=0x%zx entry=0x%llx\n", 162 pax_offset, (unsigned long long)eh->e_entry); 163 #endif 164 } 165 #else 166 static void 167 elf_placedynexec(Elf_Ehdr *eh, Elf_Phdr *ph) 168 { 169 int i; 170 171 for (i = 0; i < eh->e_phnum; i++) 172 ph[i].p_vaddr += PAGE_SIZE; 173 eh->e_entry += PAGE_SIZE; 174 } 175 #endif /* PAX_ASLR */ 176 177 /* 178 * Copy arguments onto the stack in the normal way, but add some 179 * extra information in case of dynamic binding. 180 */ 181 int 182 elf_copyargs(struct lwp *l, struct exec_package *pack, 183 struct ps_strings *arginfo, char **stackp, void *argp) 184 { 185 size_t len, vlen; 186 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 187 struct elf_args *ap; 188 int error; 189 190 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 191 return error; 192 193 a = ai; 194 execname = NULL; 195 196 /* 197 * Push extra arguments on the stack needed by dynamically 198 * linked binaries 199 */ 200 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 201 struct vattr *vap = pack->ep_vap; 202 203 a->a_type = AT_PHDR; 204 a->a_v = ap->arg_phaddr; 205 a++; 206 207 a->a_type = AT_PHENT; 208 a->a_v = ap->arg_phentsize; 209 a++; 210 211 a->a_type = AT_PHNUM; 212 a->a_v = ap->arg_phnum; 213 a++; 214 215 a->a_type = AT_PAGESZ; 216 a->a_v = PAGE_SIZE; 217 a++; 218 219 a->a_type = AT_BASE; 220 a->a_v = ap->arg_interp; 221 a++; 222 223 a->a_type = AT_FLAGS; 224 a->a_v = 0; 225 a++; 226 227 a->a_type = AT_ENTRY; 228 a->a_v = ap->arg_entry; 229 a++; 230 231 a->a_type = AT_EUID; 232 if (vap->va_mode & S_ISUID) 233 a->a_v = vap->va_uid; 234 else 235 a->a_v = kauth_cred_geteuid(l->l_cred); 236 a++; 237 238 a->a_type = AT_RUID; 239 a->a_v = kauth_cred_getuid(l->l_cred); 240 a++; 241 242 a->a_type = AT_EGID; 243 if (vap->va_mode & S_ISGID) 244 a->a_v = vap->va_gid; 245 else 246 a->a_v = kauth_cred_getegid(l->l_cred); 247 a++; 248 249 a->a_type = AT_RGID; 250 a->a_v = kauth_cred_getgid(l->l_cred); 251 a++; 252 253 if (pack->ep_path) { 254 execname = a; 255 a->a_type = AT_SUN_EXECNAME; 256 a++; 257 } 258 259 free(ap, M_TEMP); 260 pack->ep_emul_arg = NULL; 261 } 262 263 a->a_type = AT_NULL; 264 a->a_v = 0; 265 a++; 266 267 vlen = (a - ai) * sizeof(AuxInfo); 268 269 if (execname) { 270 char *path = pack->ep_path; 271 execname->a_v = (uintptr_t)(*stackp + vlen); 272 len = strlen(path) + 1; 273 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 274 return error; 275 len = ALIGN(len); 276 } else 277 len = 0; 278 279 if ((error = copyout(ai, *stackp, vlen)) != 0) 280 return error; 281 *stackp += vlen + len; 282 283 return 0; 284 } 285 286 /* 287 * elf_check_header(): 288 * 289 * Check header for validity; return 0 of ok ENOEXEC if error 290 */ 291 int 292 elf_check_header(Elf_Ehdr *eh, int type) 293 { 294 295 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 296 eh->e_ident[EI_CLASS] != ELFCLASS) 297 return ENOEXEC; 298 299 switch (eh->e_machine) { 300 301 ELFDEFNNAME(MACHDEP_ID_CASES) 302 303 default: 304 return ENOEXEC; 305 } 306 307 if (ELF_EHDR_FLAGS_OK(eh) == 0) 308 return ENOEXEC; 309 310 if (eh->e_type != type) 311 return ENOEXEC; 312 313 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 314 return ENOEXEC; 315 316 return 0; 317 } 318 319 /* 320 * elf_load_psection(): 321 * 322 * Load a psection at the appropriate address 323 */ 324 void 325 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 326 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 327 { 328 u_long msize, psize, rm, rf; 329 long diff, offset; 330 331 /* 332 * If the user specified an address, then we load there. 333 */ 334 if (*addr == ELFDEFNNAME(NO_ADDR)) 335 *addr = ph->p_vaddr; 336 337 if (ph->p_align > 1) { 338 /* 339 * Make sure we are virtually aligned as we are supposed to be. 340 */ 341 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 342 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 343 /* 344 * But make sure to not map any pages before the start of the 345 * psection by limiting the difference to within a page. 346 */ 347 diff &= PAGE_MASK; 348 } else 349 diff = 0; 350 351 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 352 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 353 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 354 355 /* 356 * Adjust everything so it all starts on a page boundary. 357 */ 358 *addr -= diff; 359 offset = ph->p_offset - diff; 360 *size = ph->p_filesz + diff; 361 msize = ph->p_memsz + diff; 362 363 if (ph->p_align >= PAGE_SIZE) { 364 if ((ph->p_flags & PF_W) != 0) { 365 /* 366 * Because the pagedvn pager can't handle zero fill 367 * of the last data page if it's not page aligned we 368 * map the last page readvn. 369 */ 370 psize = trunc_page(*size); 371 } else { 372 psize = round_page(*size); 373 } 374 } else { 375 psize = *size; 376 } 377 378 if (psize > 0) { 379 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 380 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 381 offset, *prot, flags); 382 flags &= VMCMD_RELATIVE; 383 } 384 if (psize < *size) { 385 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 386 *addr + psize, vp, offset + psize, *prot, flags); 387 } 388 389 /* 390 * Check if we need to extend the size of the segment (does 391 * bss extend page the next page boundary)? 392 */ 393 rm = round_page(*addr + msize); 394 rf = round_page(*addr + *size); 395 396 if (rm != rf) { 397 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 398 0, *prot, flags & VMCMD_RELATIVE); 399 *size = msize; 400 } 401 } 402 403 /* 404 * elf_load_file(): 405 * 406 * Load a file (interpreter/library) pointed to by path 407 * [stolen from coff_load_shlib()]. Made slightly generic 408 * so it might be used externally. 409 */ 410 int 411 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 412 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 413 Elf_Addr *last) 414 { 415 int error, i; 416 struct vnode *vp; 417 struct vattr attr; 418 Elf_Ehdr eh; 419 Elf_Phdr *ph = NULL; 420 const Elf_Phdr *ph0; 421 const Elf_Phdr *base_ph; 422 const Elf_Phdr *last_ph; 423 u_long phsize; 424 Elf_Addr addr = *last; 425 struct proc *p; 426 427 p = l->l_proc; 428 429 /* 430 * 1. open file 431 * 2. read filehdr 432 * 3. map text, data, and bss out of it using VM_* 433 */ 434 vp = epp->ep_interp; 435 if (vp == NULL) { 436 error = emul_find_interp(l, epp, path); 437 if (error != 0) 438 return error; 439 vp = epp->ep_interp; 440 } 441 /* We'll tidy this ourselves - otherwise we have locking issues */ 442 epp->ep_interp = NULL; 443 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 444 445 /* 446 * Similarly, if it's not marked as executable, or it's not a regular 447 * file, we don't allow it to be used. 448 */ 449 if (vp->v_type != VREG) { 450 error = EACCES; 451 goto badunlock; 452 } 453 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 454 goto badunlock; 455 456 /* get attributes */ 457 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 458 goto badunlock; 459 460 /* 461 * Check mount point. Though we're not trying to exec this binary, 462 * we will be executing code from it, so if the mount point 463 * disallows execution or set-id-ness, we punt or kill the set-id. 464 */ 465 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 466 error = EACCES; 467 goto badunlock; 468 } 469 if (vp->v_mount->mnt_flag & MNT_NOSUID) 470 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 471 472 #ifdef notyet /* XXX cgd 960926 */ 473 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 474 #endif 475 476 error = vn_marktext(vp); 477 if (error) 478 goto badunlock; 479 480 VOP_UNLOCK(vp, 0); 481 482 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 483 goto bad; 484 485 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 486 goto bad; 487 488 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 489 error = ENOEXEC; 490 goto bad; 491 } 492 493 phsize = eh.e_phnum * sizeof(Elf_Phdr); 494 ph = kmem_alloc(phsize, KM_SLEEP); 495 496 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 497 goto bad; 498 499 #ifdef ELF_INTERP_NON_RELOCATABLE 500 /* 501 * Evil hack: Only MIPS should be non-relocatable, and the 502 * psections should have a high address (typically 0x5ffe0000). 503 * If it's now relocatable, it should be linked at 0 and the 504 * psections should have zeros in the upper part of the address. 505 * Otherwise, force the load at the linked address. 506 */ 507 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 508 *last = ELFDEFNNAME(NO_ADDR); 509 #endif 510 511 /* 512 * If no position to load the interpreter was set by a probe 513 * function, pick the same address that a non-fixed mmap(0, ..) 514 * would (i.e. something safely out of the way). 515 */ 516 if (*last == ELFDEFNNAME(NO_ADDR)) { 517 u_long limit = 0; 518 /* 519 * Find the start and ending addresses of the psections to 520 * be loaded. This will give us the size. 521 */ 522 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 523 i++, ph0++) { 524 if (ph0->p_type == PT_LOAD) { 525 u_long psize = ph0->p_vaddr + ph0->p_memsz; 526 if (base_ph == NULL) 527 base_ph = ph0; 528 if (psize > limit) 529 limit = psize; 530 } 531 } 532 533 if (base_ph == NULL) { 534 error = ENOEXEC; 535 goto bad; 536 } 537 538 /* 539 * Now compute the size and load address. 540 */ 541 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 542 epp->ep_daddr, 543 round_page(limit) - trunc_page(base_ph->p_vaddr)); 544 } else 545 addr = *last; /* may be ELF_LINK_ADDR */ 546 547 /* 548 * Load all the necessary sections 549 */ 550 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 551 i < eh.e_phnum; i++, ph0++) { 552 switch (ph0->p_type) { 553 case PT_LOAD: { 554 u_long size; 555 int prot = 0; 556 int flags; 557 558 if (base_ph == NULL) { 559 /* 560 * First encountered psection is always the 561 * base psection. Make sure it's aligned 562 * properly (align down for topdown and align 563 * upwards for not topdown). 564 */ 565 base_ph = ph0; 566 flags = VMCMD_BASE; 567 if (addr == ELF_LINK_ADDR) 568 addr = ph0->p_vaddr; 569 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 570 addr = ELF_TRUNC(addr, ph0->p_align); 571 else 572 addr = ELF_ROUND(addr, ph0->p_align); 573 } else { 574 u_long limit = round_page(last_ph->p_vaddr 575 + last_ph->p_memsz); 576 u_long base = trunc_page(ph0->p_vaddr); 577 578 /* 579 * If there is a gap in between the psections, 580 * map it as inaccessible so nothing else 581 * mmap'ed will be placed there. 582 */ 583 if (limit != base) { 584 NEW_VMCMD2(vcset, vmcmd_map_zero, 585 base - limit, 586 limit - base_ph->p_vaddr, NULLVP, 587 0, VM_PROT_NONE, VMCMD_RELATIVE); 588 } 589 590 addr = ph0->p_vaddr - base_ph->p_vaddr; 591 flags = VMCMD_RELATIVE; 592 } 593 last_ph = ph0; 594 elf_load_psection(vcset, vp, &ph[i], &addr, 595 &size, &prot, flags); 596 /* 597 * If entry is within this psection then this 598 * must contain the .text section. *entryoff is 599 * relative to the base psection. 600 */ 601 if (eh.e_entry >= ph0->p_vaddr && 602 eh.e_entry < (ph0->p_vaddr + size)) { 603 *entryoff = eh.e_entry - base_ph->p_vaddr; 604 } 605 addr += size; 606 break; 607 } 608 609 case PT_DYNAMIC: 610 case PT_PHDR: 611 break; 612 613 case PT_NOTE: 614 break; 615 616 default: 617 break; 618 } 619 } 620 621 kmem_free(ph, phsize); 622 /* 623 * This value is ignored if TOPDOWN. 624 */ 625 *last = addr; 626 vrele(vp); 627 return 0; 628 629 badunlock: 630 VOP_UNLOCK(vp, 0); 631 632 bad: 633 if (ph != NULL) 634 kmem_free(ph, phsize); 635 #ifdef notyet /* XXX cgd 960926 */ 636 (maybe) VOP_CLOSE it 637 #endif 638 vrele(vp); 639 return error; 640 } 641 642 /* 643 * exec_elf_makecmds(): Prepare an Elf binary's exec package 644 * 645 * First, set of the various offsets/lengths in the exec package. 646 * 647 * Then, mark the text image busy (so it can be demand paged) or error 648 * out if this is not possible. Finally, set up vmcmds for the 649 * text, data, bss, and stack segments. 650 */ 651 int 652 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 653 { 654 Elf_Ehdr *eh = epp->ep_hdr; 655 Elf_Phdr *ph, *pp; 656 Elf_Addr phdr = 0, pos = 0; 657 int error, i, nload; 658 char *interp = NULL; 659 u_long phsize; 660 struct proc *p; 661 bool is_dyn; 662 663 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 664 return ENOEXEC; 665 666 is_dyn = elf_check_header(eh, ET_DYN) == 0; 667 /* 668 * XXX allow for executing shared objects. It seems silly 669 * but other ELF-based systems allow it as well. 670 */ 671 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 672 return ENOEXEC; 673 674 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 675 return ENOEXEC; 676 677 error = vn_marktext(epp->ep_vp); 678 if (error) 679 return error; 680 681 /* 682 * Allocate space to hold all the program headers, and read them 683 * from the file 684 */ 685 p = l->l_proc; 686 phsize = eh->e_phnum * sizeof(Elf_Phdr); 687 ph = kmem_alloc(phsize, KM_SLEEP); 688 689 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 690 0) 691 goto bad; 692 693 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 694 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 695 696 for (i = 0; i < eh->e_phnum; i++) { 697 pp = &ph[i]; 698 if (pp->p_type == PT_INTERP) { 699 if (pp->p_filesz >= MAXPATHLEN) { 700 error = ENOEXEC; 701 goto bad; 702 } 703 interp = PNBUF_GET(); 704 interp[0] = '\0'; 705 if ((error = exec_read_from(l, epp->ep_vp, 706 pp->p_offset, interp, pp->p_filesz)) != 0) 707 goto bad; 708 break; 709 } 710 } 711 712 /* 713 * On the same architecture, we may be emulating different systems. 714 * See which one will accept this executable. 715 * 716 * Probe functions would normally see if the interpreter (if any) 717 * exists. Emulation packages may possibly replace the interpreter in 718 * interp[] with a changed path (/emul/xxx/<path>). 719 */ 720 pos = ELFDEFNNAME(NO_ADDR); 721 if (epp->ep_esch->u.elf_probe_func) { 722 vaddr_t startp = (vaddr_t)pos; 723 724 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 725 &startp); 726 if (error) 727 goto bad; 728 pos = (Elf_Addr)startp; 729 } 730 731 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 732 p->p_pax = epp->ep_pax_flags; 733 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 734 735 if (is_dyn) 736 #ifdef PAX_ASLR 737 pax_aslr_elf(l, epp, eh, ph); 738 #else 739 elf_placedynexec(eh, ph); 740 #endif /* PAX_ASLR */ 741 742 /* 743 * Load all the necessary sections 744 */ 745 for (i = nload = 0; i < eh->e_phnum; i++) { 746 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 747 u_long size = 0; 748 int prot = 0; 749 750 pp = &ph[i]; 751 752 switch (ph[i].p_type) { 753 case PT_LOAD: 754 /* 755 * XXX 756 * Can handle only 2 sections: text and data 757 */ 758 if (nload++ == 2) { 759 error = ENOEXEC; 760 goto bad; 761 } 762 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 763 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 764 765 /* 766 * Decide whether it's text or data by looking 767 * at the entry point. 768 */ 769 if (eh->e_entry >= addr && 770 eh->e_entry < (addr + size)) { 771 epp->ep_taddr = addr; 772 epp->ep_tsize = size; 773 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 774 epp->ep_daddr = addr; 775 epp->ep_dsize = size; 776 } 777 } else { 778 epp->ep_daddr = addr; 779 epp->ep_dsize = size; 780 } 781 break; 782 783 case PT_SHLIB: 784 /* SCO has these sections. */ 785 case PT_INTERP: 786 /* Already did this one. */ 787 case PT_DYNAMIC: 788 break; 789 case PT_NOTE: 790 break; 791 case PT_PHDR: 792 /* Note address of program headers (in text segment) */ 793 phdr = pp->p_vaddr; 794 break; 795 796 default: 797 /* 798 * Not fatal; we don't need to understand everything. 799 */ 800 break; 801 } 802 } 803 804 /* 805 * Check if we found a dynamically linked binary and arrange to load 806 * its interpreter 807 */ 808 if (interp) { 809 struct elf_args *ap; 810 int j = epp->ep_vmcmds.evs_used; 811 u_long interp_offset; 812 813 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 814 M_TEMP, M_WAITOK); 815 if ((error = elf_load_file(l, epp, interp, 816 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 817 free(ap, M_TEMP); 818 goto bad; 819 } 820 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 821 epp->ep_entry = ap->arg_interp + interp_offset; 822 ap->arg_phaddr = phdr; 823 824 ap->arg_phentsize = eh->e_phentsize; 825 ap->arg_phnum = eh->e_phnum; 826 ap->arg_entry = eh->e_entry; 827 828 epp->ep_emul_arg = ap; 829 830 PNBUF_PUT(interp); 831 } else 832 epp->ep_entry = eh->e_entry; 833 834 #ifdef ELF_MAP_PAGE_ZERO 835 /* Dell SVR4 maps page zero, yeuch! */ 836 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 837 epp->ep_vp, 0, VM_PROT_READ); 838 #endif 839 kmem_free(ph, phsize); 840 return (*epp->ep_esch->es_setup_stack)(l, epp); 841 842 bad: 843 if (interp) 844 PNBUF_PUT(interp); 845 kmem_free(ph, phsize); 846 kill_vmcmds(&epp->ep_vmcmds); 847 return error; 848 } 849 850 int 851 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 852 Elf_Ehdr *eh) 853 { 854 size_t i; 855 Elf_Shdr *sh; 856 Elf_Nhdr *np; 857 size_t shsize; 858 int error; 859 int isnetbsd = 0; 860 char *ndata; 861 862 epp->ep_pax_flags = 0; 863 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 864 return ENOEXEC; 865 866 shsize = eh->e_shnum * sizeof(Elf_Shdr); 867 sh = kmem_alloc(shsize, KM_SLEEP); 868 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 869 if (error) 870 goto out; 871 872 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 873 for (i = 0; i < eh->e_shnum; i++) { 874 Elf_Shdr *shp = &sh[i]; 875 876 if (shp->sh_type != SHT_NOTE || 877 shp->sh_size > MAXNOTESIZE || 878 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 879 continue; 880 881 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 882 shp->sh_size); 883 if (error) 884 continue; 885 886 ndata = (char *)(np + 1); 887 switch (np->n_type) { 888 case ELF_NOTE_TYPE_NETBSD_TAG: 889 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 890 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 891 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 892 ELF_NOTE_NETBSD_NAMESZ)) 893 goto bad; 894 isnetbsd = 1; 895 break; 896 897 case ELF_NOTE_TYPE_PAX_TAG: 898 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 899 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 900 memcmp(ndata, ELF_NOTE_PAX_NAME, 901 ELF_NOTE_PAX_NAMESZ)) { 902 bad: 903 #ifdef DIAGNOSTIC 904 printf("%s: bad tag %d: " 905 "[%d %d, %d %d, %*.*s %*.*s]\n", 906 epp->ep_name, 907 np->n_type 908 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 909 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 910 ELF_NOTE_PAX_NAMESZ, 911 ELF_NOTE_PAX_NAMESZ, 912 ndata, 913 ELF_NOTE_PAX_NAMESZ, 914 ELF_NOTE_PAX_NAMESZ, 915 ELF_NOTE_PAX_NAME); 916 #endif 917 continue; 918 } 919 (void)memcpy(&epp->ep_pax_flags, 920 ndata + ELF_NOTE_PAX_NAMESZ, 921 sizeof(epp->ep_pax_flags)); 922 break; 923 924 default: 925 #ifdef DIAGNOSTIC 926 printf("%s: unknown note type %d\n", epp->ep_name, 927 np->n_type); 928 #endif 929 break; 930 } 931 } 932 kmem_free(np, MAXNOTESIZE); 933 934 error = isnetbsd ? 0 : ENOEXEC; 935 out: 936 kmem_free(sh, shsize); 937 return error; 938 } 939 940 int 941 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 942 vaddr_t *pos) 943 { 944 int error; 945 946 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 947 return error; 948 #ifdef ELF_MD_PROBE_FUNC 949 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 950 return error; 951 #elif defined(ELF_INTERP_NON_RELOCATABLE) 952 *pos = ELF_LINK_ADDR; 953 #endif 954 return 0; 955 } 956
Indexes created Mon Sep 22 05:09:51 GMT 2025