exec_elf.c revision 1.14
1 /* $NetBSD: exec_elf.c,v 1.14 2010/03/15 20:35:20 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 1.14 2010/03/15 20:35:20 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 #define MAXPHNUM 50 113 114 #ifdef PAX_ASLR 115 /* 116 * We don't move this code in kern_pax.c because it is compiled twice. 117 */ 118 static void 119 pax_aslr_elf(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 120 Elf_Phdr *ph) 121 { 122 size_t pax_align = 0, pax_offset, i; 123 uint32_t r; 124 125 if (!pax_aslr_active(l)) 126 return; 127 128 /* 129 * find align XXX: not all sections might have the same 130 * alignment 131 */ 132 for (i = 0; i < eh->e_phnum; i++) 133 if (ph[i].p_type == PT_LOAD) { 134 pax_align = ph[i].p_align; 135 break; 136 } 137 138 r = arc4random(); 139 140 if (pax_align == 0) 141 pax_align = PGSHIFT; 142 #ifdef PAX_ASLR_DEBUG 143 uprintf("r=0x%x a=0x%x p=0x%x Delta=0x%lx\n", r, 144 ilog2(pax_align), PGSHIFT, PAX_ASLR_DELTA(r, 145 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN)); 146 #endif 147 pax_offset = ELF_TRUNC(PAX_ASLR_DELTA(r, 148 ilog2(pax_align), PAX_ASLR_DELTA_EXEC_LEN), pax_align) + PAGE_SIZE; 149 150 for (i = 0; i < eh->e_phnum; i++) 151 ph[i].p_vaddr += pax_offset; 152 eh->e_entry += pax_offset; 153 #ifdef PAX_ASLR_DEBUG 154 uprintf("pax offset=0x%zx entry=0x%llx\n", 155 pax_offset, (unsigned long long)eh->e_entry); 156 #endif 157 } 158 #else 159 static void 160 elf_placedynexec(Elf_Ehdr *eh, Elf_Phdr *ph) 161 { 162 int i; 163 164 for (i = 0; i < eh->e_phnum; i++) 165 ph[i].p_vaddr += PAGE_SIZE; 166 eh->e_entry += PAGE_SIZE; 167 } 168 #endif /* PAX_ASLR */ 169 170 /* 171 * Copy arguments onto the stack in the normal way, but add some 172 * extra information in case of dynamic binding. 173 */ 174 int 175 elf_copyargs(struct lwp *l, struct exec_package *pack, 176 struct ps_strings *arginfo, char **stackp, void *argp) 177 { 178 size_t len, vlen; 179 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 180 struct elf_args *ap; 181 int error; 182 183 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 184 return error; 185 186 a = ai; 187 execname = NULL; 188 189 /* 190 * Push extra arguments on the stack needed by dynamically 191 * linked binaries 192 */ 193 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 194 struct vattr *vap = pack->ep_vap; 195 196 a->a_type = AT_PHDR; 197 a->a_v = ap->arg_phaddr; 198 a++; 199 200 a->a_type = AT_PHENT; 201 a->a_v = ap->arg_phentsize; 202 a++; 203 204 a->a_type = AT_PHNUM; 205 a->a_v = ap->arg_phnum; 206 a++; 207 208 a->a_type = AT_PAGESZ; 209 a->a_v = PAGE_SIZE; 210 a++; 211 212 a->a_type = AT_BASE; 213 a->a_v = ap->arg_interp; 214 a++; 215 216 a->a_type = AT_FLAGS; 217 a->a_v = 0; 218 a++; 219 220 a->a_type = AT_ENTRY; 221 a->a_v = ap->arg_entry; 222 a++; 223 224 a->a_type = AT_EUID; 225 if (vap->va_mode & S_ISUID) 226 a->a_v = vap->va_uid; 227 else 228 a->a_v = kauth_cred_geteuid(l->l_cred); 229 a++; 230 231 a->a_type = AT_RUID; 232 a->a_v = kauth_cred_getuid(l->l_cred); 233 a++; 234 235 a->a_type = AT_EGID; 236 if (vap->va_mode & S_ISGID) 237 a->a_v = vap->va_gid; 238 else 239 a->a_v = kauth_cred_getegid(l->l_cred); 240 a++; 241 242 a->a_type = AT_RGID; 243 a->a_v = kauth_cred_getgid(l->l_cred); 244 a++; 245 246 if (pack->ep_path) { 247 execname = a; 248 a->a_type = AT_SUN_EXECNAME; 249 a++; 250 } 251 252 free(ap, M_TEMP); 253 pack->ep_emul_arg = NULL; 254 } 255 256 a->a_type = AT_NULL; 257 a->a_v = 0; 258 a++; 259 260 vlen = (a - ai) * sizeof(AuxInfo); 261 262 if (execname) { 263 char *path = pack->ep_path; 264 execname->a_v = (uintptr_t)(*stackp + vlen); 265 len = strlen(path) + 1; 266 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 267 return error; 268 len = ALIGN(len); 269 } else 270 len = 0; 271 272 if ((error = copyout(ai, *stackp, vlen)) != 0) 273 return error; 274 *stackp += vlen + len; 275 276 return 0; 277 } 278 279 /* 280 * elf_check_header(): 281 * 282 * Check header for validity; return 0 of ok ENOEXEC if error 283 */ 284 int 285 elf_check_header(Elf_Ehdr *eh, int type) 286 { 287 288 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 289 eh->e_ident[EI_CLASS] != ELFCLASS) 290 return ENOEXEC; 291 292 switch (eh->e_machine) { 293 294 ELFDEFNNAME(MACHDEP_ID_CASES) 295 296 default: 297 return ENOEXEC; 298 } 299 300 if (ELF_EHDR_FLAGS_OK(eh) == 0) 301 return ENOEXEC; 302 303 if (eh->e_type != type) 304 return ENOEXEC; 305 306 if (eh->e_shnum > 32768 || eh->e_phnum > 128) 307 return ENOEXEC; 308 309 return 0; 310 } 311 312 /* 313 * elf_load_psection(): 314 * 315 * Load a psection at the appropriate address 316 */ 317 void 318 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 319 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 320 { 321 u_long msize, psize, rm, rf; 322 long diff, offset; 323 324 /* 325 * If the user specified an address, then we load there. 326 */ 327 if (*addr == ELFDEFNNAME(NO_ADDR)) 328 *addr = ph->p_vaddr; 329 330 if (ph->p_align > 1) { 331 /* 332 * Make sure we are virtually aligned as we are supposed to be. 333 */ 334 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 335 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 336 /* 337 * But make sure to not map any pages before the start of the 338 * psection by limiting the difference to within a page. 339 */ 340 diff &= PAGE_MASK; 341 } else 342 diff = 0; 343 344 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 345 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 346 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 347 348 /* 349 * Adjust everything so it all starts on a page boundary. 350 */ 351 *addr -= diff; 352 offset = ph->p_offset - diff; 353 *size = ph->p_filesz + diff; 354 msize = ph->p_memsz + diff; 355 356 if (ph->p_align >= PAGE_SIZE) { 357 if ((ph->p_flags & PF_W) != 0) { 358 /* 359 * Because the pagedvn pager can't handle zero fill 360 * of the last data page if it's not page aligned we 361 * map the last page readvn. 362 */ 363 psize = trunc_page(*size); 364 } else { 365 psize = round_page(*size); 366 } 367 } else { 368 psize = *size; 369 } 370 371 if (psize > 0) { 372 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 373 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 374 offset, *prot, flags); 375 flags &= VMCMD_RELATIVE; 376 } 377 if (psize < *size) { 378 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 379 *addr + psize, vp, offset + psize, *prot, flags); 380 } 381 382 /* 383 * Check if we need to extend the size of the segment (does 384 * bss extend page the next page boundary)? 385 */ 386 rm = round_page(*addr + msize); 387 rf = round_page(*addr + *size); 388 389 if (rm != rf) { 390 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 391 0, *prot, flags & VMCMD_RELATIVE); 392 *size = msize; 393 } 394 } 395 396 /* 397 * elf_load_file(): 398 * 399 * Load a file (interpreter/library) pointed to by path 400 * [stolen from coff_load_shlib()]. Made slightly generic 401 * so it might be used externally. 402 */ 403 int 404 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 405 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 406 Elf_Addr *last) 407 { 408 int error, i; 409 struct vnode *vp; 410 struct vattr attr; 411 Elf_Ehdr eh; 412 Elf_Phdr *ph = NULL; 413 const Elf_Phdr *ph0; 414 const Elf_Phdr *base_ph; 415 const Elf_Phdr *last_ph; 416 u_long phsize; 417 Elf_Addr addr = *last; 418 struct proc *p; 419 420 p = l->l_proc; 421 422 /* 423 * 1. open file 424 * 2. read filehdr 425 * 3. map text, data, and bss out of it using VM_* 426 */ 427 vp = epp->ep_interp; 428 if (vp == NULL) { 429 error = emul_find_interp(l, epp, path); 430 if (error != 0) 431 return error; 432 vp = epp->ep_interp; 433 } 434 /* We'll tidy this ourselves - otherwise we have locking issues */ 435 epp->ep_interp = NULL; 436 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 437 438 /* 439 * Similarly, if it's not marked as executable, or it's not a regular 440 * file, we don't allow it to be used. 441 */ 442 if (vp->v_type != VREG) { 443 error = EACCES; 444 goto badunlock; 445 } 446 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 447 goto badunlock; 448 449 /* get attributes */ 450 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 451 goto badunlock; 452 453 /* 454 * Check mount point. Though we're not trying to exec this binary, 455 * we will be executing code from it, so if the mount point 456 * disallows execution or set-id-ness, we punt or kill the set-id. 457 */ 458 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 459 error = EACCES; 460 goto badunlock; 461 } 462 if (vp->v_mount->mnt_flag & MNT_NOSUID) 463 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 464 465 #ifdef notyet /* XXX cgd 960926 */ 466 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 467 #endif 468 469 error = vn_marktext(vp); 470 if (error) 471 goto badunlock; 472 473 VOP_UNLOCK(vp, 0); 474 475 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 476 goto bad; 477 478 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 479 goto bad; 480 481 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 482 error = ENOEXEC; 483 goto bad; 484 } 485 486 phsize = eh.e_phnum * sizeof(Elf_Phdr); 487 ph = kmem_alloc(phsize, KM_SLEEP); 488 489 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 490 goto bad; 491 492 #ifdef ELF_INTERP_NON_RELOCATABLE 493 /* 494 * Evil hack: Only MIPS should be non-relocatable, and the 495 * psections should have a high address (typically 0x5ffe0000). 496 * If it's now relocatable, it should be linked at 0 and the 497 * psections should have zeros in the upper part of the address. 498 * Otherwise, force the load at the linked address. 499 */ 500 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 501 *last = ELFDEFNNAME(NO_ADDR); 502 #endif 503 504 /* 505 * If no position to load the interpreter was set by a probe 506 * function, pick the same address that a non-fixed mmap(0, ..) 507 * would (i.e. something safely out of the way). 508 */ 509 if (*last == ELFDEFNNAME(NO_ADDR)) { 510 u_long limit = 0; 511 /* 512 * Find the start and ending addresses of the psections to 513 * be loaded. This will give us the size. 514 */ 515 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 516 i++, ph0++) { 517 if (ph0->p_type == PT_LOAD) { 518 u_long psize = ph0->p_vaddr + ph0->p_memsz; 519 if (base_ph == NULL) 520 base_ph = ph0; 521 if (psize > limit) 522 limit = psize; 523 } 524 } 525 526 if (base_ph == NULL) { 527 error = ENOEXEC; 528 goto bad; 529 } 530 531 /* 532 * Now compute the size and load address. 533 */ 534 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 535 epp->ep_daddr, 536 round_page(limit) - trunc_page(base_ph->p_vaddr)); 537 } else 538 addr = *last; /* may be ELF_LINK_ADDR */ 539 540 /* 541 * Load all the necessary sections 542 */ 543 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 544 i < eh.e_phnum; i++, ph0++) { 545 switch (ph0->p_type) { 546 case PT_LOAD: { 547 u_long size; 548 int prot = 0; 549 int flags; 550 551 if (base_ph == NULL) { 552 /* 553 * First encountered psection is always the 554 * base psection. Make sure it's aligned 555 * properly (align down for topdown and align 556 * upwards for not topdown). 557 */ 558 base_ph = ph0; 559 flags = VMCMD_BASE; 560 if (addr == ELF_LINK_ADDR) 561 addr = ph0->p_vaddr; 562 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 563 addr = ELF_TRUNC(addr, ph0->p_align); 564 else 565 addr = ELF_ROUND(addr, ph0->p_align); 566 } else { 567 u_long limit = round_page(last_ph->p_vaddr 568 + last_ph->p_memsz); 569 u_long base = trunc_page(ph0->p_vaddr); 570 571 /* 572 * If there is a gap in between the psections, 573 * map it as inaccessible so nothing else 574 * mmap'ed will be placed there. 575 */ 576 if (limit != base) { 577 NEW_VMCMD2(vcset, vmcmd_map_zero, 578 base - limit, 579 limit - base_ph->p_vaddr, NULLVP, 580 0, VM_PROT_NONE, VMCMD_RELATIVE); 581 } 582 583 addr = ph0->p_vaddr - base_ph->p_vaddr; 584 flags = VMCMD_RELATIVE; 585 } 586 last_ph = ph0; 587 elf_load_psection(vcset, vp, &ph[i], &addr, 588 &size, &prot, flags); 589 /* 590 * If entry is within this psection then this 591 * must contain the .text section. *entryoff is 592 * relative to the base psection. 593 */ 594 if (eh.e_entry >= ph0->p_vaddr && 595 eh.e_entry < (ph0->p_vaddr + size)) { 596 *entryoff = eh.e_entry - base_ph->p_vaddr; 597 } 598 addr += size; 599 break; 600 } 601 602 case PT_DYNAMIC: 603 case PT_PHDR: 604 break; 605 606 case PT_NOTE: 607 break; 608 609 default: 610 break; 611 } 612 } 613 614 kmem_free(ph, phsize); 615 /* 616 * This value is ignored if TOPDOWN. 617 */ 618 *last = addr; 619 vrele(vp); 620 return 0; 621 622 badunlock: 623 VOP_UNLOCK(vp, 0); 624 625 bad: 626 if (ph != NULL) 627 kmem_free(ph, phsize); 628 #ifdef notyet /* XXX cgd 960926 */ 629 (maybe) VOP_CLOSE it 630 #endif 631 vrele(vp); 632 return error; 633 } 634 635 /* 636 * exec_elf_makecmds(): Prepare an Elf binary's exec package 637 * 638 * First, set of the various offsets/lengths in the exec package. 639 * 640 * Then, mark the text image busy (so it can be demand paged) or error 641 * out if this is not possible. Finally, set up vmcmds for the 642 * text, data, bss, and stack segments. 643 */ 644 int 645 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 646 { 647 Elf_Ehdr *eh = epp->ep_hdr; 648 Elf_Phdr *ph, *pp; 649 Elf_Addr phdr = 0, pos = 0; 650 int error, i, nload; 651 char *interp = NULL; 652 u_long phsize; 653 struct proc *p; 654 bool is_dyn; 655 656 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 657 return ENOEXEC; 658 659 is_dyn = elf_check_header(eh, ET_DYN) == 0; 660 /* 661 * XXX allow for executing shared objects. It seems silly 662 * but other ELF-based systems allow it as well. 663 */ 664 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 665 return ENOEXEC; 666 667 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 668 return ENOEXEC; 669 670 error = vn_marktext(epp->ep_vp); 671 if (error) 672 return error; 673 674 /* 675 * Allocate space to hold all the program headers, and read them 676 * from the file 677 */ 678 p = l->l_proc; 679 phsize = eh->e_phnum * sizeof(Elf_Phdr); 680 ph = kmem_alloc(phsize, KM_SLEEP); 681 682 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 683 0) 684 goto bad; 685 686 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 687 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 688 689 for (i = 0; i < eh->e_phnum; i++) { 690 pp = &ph[i]; 691 if (pp->p_type == PT_INTERP) { 692 if (pp->p_filesz >= MAXPATHLEN) { 693 error = ENOEXEC; 694 goto bad; 695 } 696 interp = PNBUF_GET(); 697 interp[0] = '\0'; 698 if ((error = exec_read_from(l, epp->ep_vp, 699 pp->p_offset, interp, pp->p_filesz)) != 0) 700 goto bad; 701 break; 702 } 703 } 704 705 /* 706 * On the same architecture, we may be emulating different systems. 707 * See which one will accept this executable. 708 * 709 * Probe functions would normally see if the interpreter (if any) 710 * exists. Emulation packages may possibly replace the interpreter in 711 * interp[] with a changed path (/emul/xxx/<path>). 712 */ 713 pos = ELFDEFNNAME(NO_ADDR); 714 if (epp->ep_esch->u.elf_probe_func) { 715 vaddr_t startp = (vaddr_t)pos; 716 717 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 718 &startp); 719 if (error) 720 goto bad; 721 pos = (Elf_Addr)startp; 722 } 723 724 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 725 p->p_pax = epp->ep_pax_flags; 726 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 727 728 if (is_dyn) 729 #ifdef PAX_ASLR 730 pax_aslr_elf(l, epp, eh, ph); 731 #else 732 elf_placedynexec(eh, ph); 733 #endif /* PAX_ASLR */ 734 735 /* 736 * Load all the necessary sections 737 */ 738 for (i = nload = 0; i < eh->e_phnum; i++) { 739 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 740 u_long size = 0; 741 int prot = 0; 742 743 pp = &ph[i]; 744 745 switch (ph[i].p_type) { 746 case PT_LOAD: 747 /* 748 * XXX 749 * Can handle only 2 sections: text and data 750 */ 751 if (nload++ == 2) { 752 error = ENOEXEC; 753 goto bad; 754 } 755 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 756 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 757 758 /* 759 * Decide whether it's text or data by looking 760 * at the entry point. 761 */ 762 if (eh->e_entry >= addr && 763 eh->e_entry < (addr + size)) { 764 epp->ep_taddr = addr; 765 epp->ep_tsize = size; 766 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 767 epp->ep_daddr = addr; 768 epp->ep_dsize = size; 769 } 770 } else { 771 epp->ep_daddr = addr; 772 epp->ep_dsize = size; 773 } 774 break; 775 776 case PT_SHLIB: 777 /* SCO has these sections. */ 778 case PT_INTERP: 779 /* Already did this one. */ 780 case PT_DYNAMIC: 781 break; 782 case PT_NOTE: 783 break; 784 case PT_PHDR: 785 /* Note address of program headers (in text segment) */ 786 phdr = pp->p_vaddr; 787 break; 788 789 default: 790 /* 791 * Not fatal; we don't need to understand everything. 792 */ 793 break; 794 } 795 } 796 797 /* 798 * Check if we found a dynamically linked binary and arrange to load 799 * its interpreter 800 */ 801 if (interp) { 802 struct elf_args *ap; 803 int j = epp->ep_vmcmds.evs_used; 804 u_long interp_offset; 805 806 ap = (struct elf_args *)malloc(sizeof(struct elf_args), 807 M_TEMP, M_WAITOK); 808 if ((error = elf_load_file(l, epp, interp, 809 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 810 free(ap, M_TEMP); 811 goto bad; 812 } 813 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 814 epp->ep_entry = ap->arg_interp + interp_offset; 815 ap->arg_phaddr = phdr; 816 817 ap->arg_phentsize = eh->e_phentsize; 818 ap->arg_phnum = eh->e_phnum; 819 ap->arg_entry = eh->e_entry; 820 821 epp->ep_emul_arg = ap; 822 823 PNBUF_PUT(interp); 824 } else 825 epp->ep_entry = eh->e_entry; 826 827 #ifdef ELF_MAP_PAGE_ZERO 828 /* Dell SVR4 maps page zero, yeuch! */ 829 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 830 epp->ep_vp, 0, VM_PROT_READ); 831 #endif 832 kmem_free(ph, phsize); 833 return (*epp->ep_esch->es_setup_stack)(l, epp); 834 835 bad: 836 if (interp) 837 PNBUF_PUT(interp); 838 kmem_free(ph, phsize); 839 kill_vmcmds(&epp->ep_vmcmds); 840 return error; 841 } 842 843 int 844 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 845 Elf_Ehdr *eh) 846 { 847 size_t i; 848 Elf_Phdr *ph; 849 size_t phsize; 850 int error; 851 int isnetbsd = 0; 852 char *ndata; 853 854 epp->ep_pax_flags = 0; 855 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 856 return ENOEXEC; 857 858 phsize = eh->e_phnum * sizeof(Elf_Phdr); 859 ph = kmem_alloc(phsize, KM_SLEEP); 860 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 861 if (error) 862 goto out; 863 864 for (i = 0; i < eh->e_phnum; i++) { 865 Elf_Phdr *ephp = &ph[i]; 866 Elf_Nhdr *np; 867 868 if (ephp->p_type != PT_NOTE || 869 ephp->p_filesz > 1024 || 870 ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 871 continue; 872 873 np = kmem_alloc(ephp->p_filesz, KM_SLEEP); 874 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, 875 ephp->p_filesz); 876 if (error) 877 goto next; 878 879 ndata = (char *)(np + 1); 880 switch (np->n_type) { 881 case ELF_NOTE_TYPE_NETBSD_TAG: 882 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 883 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 884 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 885 ELF_NOTE_NETBSD_NAMESZ)) 886 goto next; 887 isnetbsd = 1; 888 break; 889 890 case ELF_NOTE_TYPE_PAX_TAG: 891 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 892 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 893 memcmp(ndata, ELF_NOTE_PAX_NAME, 894 ELF_NOTE_PAX_NAMESZ)) 895 goto next; 896 (void)memcpy(&epp->ep_pax_flags, 897 ndata + ELF_NOTE_PAX_NAMESZ, 898 sizeof(epp->ep_pax_flags)); 899 break; 900 901 default: 902 break; 903 } 904 905 next: 906 kmem_free(np, ephp->p_filesz); 907 continue; 908 } 909 910 error = isnetbsd ? 0 : ENOEXEC; 911 out: 912 kmem_free(ph, phsize); 913 return error; 914 } 915 916 int 917 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 918 vaddr_t *pos) 919 { 920 int error; 921 922 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 923 return error; 924 #ifdef ELF_MD_PROBE_FUNC 925 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 926 return error; 927 #elif defined(ELF_INTERP_NON_RELOCATABLE) 928 *pos = ELF_LINK_ADDR; 929 #endif 930 return 0; 931 } 932
Indexes created Mon Sep 22 13:09:51 GMT 2025