exec_elf.c revision 1.34
1 /* $NetBSD: exec_elf.c,v 1.34 2012/02/01 21:49:52 matt 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 1.34 2012/02/01 21:49:52 matt 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/kmem.h> 69 #include <sys/namei.h> 70 #include <sys/vnode.h> 71 #include <sys/exec.h> 72 #include <sys/exec_elf.h> 73 #include <sys/syscall.h> 74 #include <sys/signalvar.h> 75 #include <sys/mount.h> 76 #include <sys/stat.h> 77 #include <sys/kauth.h> 78 #include <sys/bitops.h> 79 #include <sys/cprng.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 = cprng_fast32(); 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%llx entry=0x%llx\n", 148 (unsigned long long)offset, 149 (unsigned long long)eh->e_entry); 150 #endif /* PAX_ASLR_DEBUG */ 151 } else 152 #endif /* PAX_ASLR */ 153 offset = MAX(align, PAGE_SIZE); 154 155 offset += epp->ep_vm_minaddr; 156 157 for (i = 0; i < eh->e_phnum; i++) 158 ph[i].p_vaddr += offset; 159 eh->e_entry += offset; 160 } 161 162 /* 163 * Copy arguments onto the stack in the normal way, but add some 164 * extra information in case of dynamic binding. 165 */ 166 int 167 elf_copyargs(struct lwp *l, struct exec_package *pack, 168 struct ps_strings *arginfo, char **stackp, void *argp) 169 { 170 size_t len, vlen; 171 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 172 struct elf_args *ap; 173 int error; 174 175 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 176 return error; 177 178 a = ai; 179 execname = NULL; 180 181 /* 182 * Push extra arguments on the stack needed by dynamically 183 * linked binaries 184 */ 185 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 186 struct vattr *vap = pack->ep_vap; 187 188 a->a_type = AT_PHDR; 189 a->a_v = ap->arg_phaddr; 190 a++; 191 192 a->a_type = AT_PHENT; 193 a->a_v = ap->arg_phentsize; 194 a++; 195 196 a->a_type = AT_PHNUM; 197 a->a_v = ap->arg_phnum; 198 a++; 199 200 a->a_type = AT_PAGESZ; 201 a->a_v = PAGE_SIZE; 202 a++; 203 204 a->a_type = AT_BASE; 205 a->a_v = ap->arg_interp; 206 a++; 207 208 a->a_type = AT_FLAGS; 209 a->a_v = 0; 210 a++; 211 212 a->a_type = AT_ENTRY; 213 a->a_v = ap->arg_entry; 214 a++; 215 216 a->a_type = AT_EUID; 217 if (vap->va_mode & S_ISUID) 218 a->a_v = vap->va_uid; 219 else 220 a->a_v = kauth_cred_geteuid(l->l_cred); 221 a++; 222 223 a->a_type = AT_RUID; 224 a->a_v = kauth_cred_getuid(l->l_cred); 225 a++; 226 227 a->a_type = AT_EGID; 228 if (vap->va_mode & S_ISGID) 229 a->a_v = vap->va_gid; 230 else 231 a->a_v = kauth_cred_getegid(l->l_cred); 232 a++; 233 234 a->a_type = AT_RGID; 235 a->a_v = kauth_cred_getgid(l->l_cred); 236 a++; 237 238 if (pack->ep_path) { 239 execname = a; 240 a->a_type = AT_SUN_EXECNAME; 241 a++; 242 } 243 244 kmem_free(ap, sizeof(*ap)); 245 pack->ep_emul_arg = NULL; 246 } 247 248 a->a_type = AT_NULL; 249 a->a_v = 0; 250 a++; 251 252 vlen = (a - ai) * sizeof(AuxInfo); 253 254 if (execname) { 255 char *path = pack->ep_path; 256 execname->a_v = (uintptr_t)(*stackp + vlen); 257 len = strlen(path) + 1; 258 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 259 return error; 260 len = ALIGN(len); 261 } else 262 len = 0; 263 264 if ((error = copyout(ai, *stackp, vlen)) != 0) 265 return error; 266 *stackp += vlen + len; 267 268 return 0; 269 } 270 271 /* 272 * elf_check_header(): 273 * 274 * Check header for validity; return 0 of ok ENOEXEC if error 275 */ 276 int 277 elf_check_header(Elf_Ehdr *eh, int type) 278 { 279 280 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 281 eh->e_ident[EI_CLASS] != ELFCLASS) 282 return ENOEXEC; 283 284 switch (eh->e_machine) { 285 286 ELFDEFNNAME(MACHDEP_ID_CASES) 287 288 default: 289 return ENOEXEC; 290 } 291 292 if (ELF_EHDR_FLAGS_OK(eh) == 0) 293 return ENOEXEC; 294 295 if (eh->e_type != type) 296 return ENOEXEC; 297 298 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 299 return ENOEXEC; 300 301 return 0; 302 } 303 304 /* 305 * elf_load_psection(): 306 * 307 * Load a psection at the appropriate address 308 */ 309 void 310 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 311 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 312 { 313 u_long msize, psize, rm, rf; 314 long diff, offset; 315 316 /* 317 * If the user specified an address, then we load there. 318 */ 319 if (*addr == ELFDEFNNAME(NO_ADDR)) 320 *addr = ph->p_vaddr; 321 322 if (ph->p_align > 1) { 323 /* 324 * Make sure we are virtually aligned as we are supposed to be. 325 */ 326 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 327 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 328 /* 329 * But make sure to not map any pages before the start of the 330 * psection by limiting the difference to within a page. 331 */ 332 diff &= PAGE_MASK; 333 } else 334 diff = 0; 335 336 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 337 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 338 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 339 340 /* 341 * Adjust everything so it all starts on a page boundary. 342 */ 343 *addr -= diff; 344 offset = ph->p_offset - diff; 345 *size = ph->p_filesz + diff; 346 msize = ph->p_memsz + diff; 347 348 if (ph->p_align >= PAGE_SIZE) { 349 if ((ph->p_flags & PF_W) != 0) { 350 /* 351 * Because the pagedvn pager can't handle zero fill 352 * of the last data page if it's not page aligned we 353 * map the last page readvn. 354 */ 355 psize = trunc_page(*size); 356 } else { 357 psize = round_page(*size); 358 } 359 } else { 360 psize = *size; 361 } 362 363 if (psize > 0) { 364 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 365 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 366 offset, *prot, flags); 367 flags &= VMCMD_RELATIVE; 368 } 369 if (psize < *size) { 370 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 371 *addr + psize, vp, offset + psize, *prot, flags); 372 } 373 374 /* 375 * Check if we need to extend the size of the segment (does 376 * bss extend page the next page boundary)? 377 */ 378 rm = round_page(*addr + msize); 379 rf = round_page(*addr + *size); 380 381 if (rm != rf) { 382 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 383 0, *prot, flags & VMCMD_RELATIVE); 384 *size = msize; 385 } 386 } 387 388 /* 389 * elf_load_file(): 390 * 391 * Load a file (interpreter/library) pointed to by path 392 * [stolen from coff_load_shlib()]. Made slightly generic 393 * so it might be used externally. 394 */ 395 int 396 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 397 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 398 Elf_Addr *last) 399 { 400 int error, i; 401 struct vnode *vp; 402 struct vattr attr; 403 Elf_Ehdr eh; 404 Elf_Phdr *ph = NULL; 405 const Elf_Phdr *ph0; 406 const Elf_Phdr *base_ph; 407 const Elf_Phdr *last_ph; 408 u_long phsize; 409 Elf_Addr addr = *last; 410 struct proc *p; 411 412 p = l->l_proc; 413 414 /* 415 * 1. open file 416 * 2. read filehdr 417 * 3. map text, data, and bss out of it using VM_* 418 */ 419 vp = epp->ep_interp; 420 if (vp == NULL) { 421 error = emul_find_interp(l, epp, path); 422 if (error != 0) 423 return error; 424 vp = epp->ep_interp; 425 } 426 /* We'll tidy this ourselves - otherwise we have locking issues */ 427 epp->ep_interp = NULL; 428 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 429 430 /* 431 * Similarly, if it's not marked as executable, or it's not a regular 432 * file, we don't allow it to be used. 433 */ 434 if (vp->v_type != VREG) { 435 error = EACCES; 436 goto badunlock; 437 } 438 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 439 goto badunlock; 440 441 /* get attributes */ 442 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 443 goto badunlock; 444 445 /* 446 * Check mount point. Though we're not trying to exec this binary, 447 * we will be executing code from it, so if the mount point 448 * disallows execution or set-id-ness, we punt or kill the set-id. 449 */ 450 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 451 error = EACCES; 452 goto badunlock; 453 } 454 if (vp->v_mount->mnt_flag & MNT_NOSUID) 455 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 456 457 #ifdef notyet /* XXX cgd 960926 */ 458 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 459 460 XXXps: this problem will make it impossible to use an interpreter 461 from a file system which actually does something in VOP_OPEN 462 #endif 463 464 error = vn_marktext(vp); 465 if (error) 466 goto badunlock; 467 468 VOP_UNLOCK(vp); 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); 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, computed_phdr = 0, pos = 0, end_text = 0; 645 int error, i, nload; 646 char *interp = NULL; 647 u_long phsize; 648 struct proc *p; 649 struct elf_args *ap = NULL; 650 bool is_dyn; 651 652 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 653 return ENOEXEC; 654 655 is_dyn = elf_check_header(eh, ET_DYN) == 0; 656 /* 657 * XXX allow for executing shared objects. It seems silly 658 * but other ELF-based systems allow it as well. 659 */ 660 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 661 return ENOEXEC; 662 663 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 664 return ENOEXEC; 665 666 error = vn_marktext(epp->ep_vp); 667 if (error) 668 return error; 669 670 /* 671 * Allocate space to hold all the program headers, and read them 672 * from the file 673 */ 674 p = l->l_proc; 675 phsize = eh->e_phnum * sizeof(Elf_Phdr); 676 ph = kmem_alloc(phsize, KM_SLEEP); 677 678 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 679 0) 680 goto bad; 681 682 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 683 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 684 685 for (i = 0; i < eh->e_phnum; i++) { 686 pp = &ph[i]; 687 if (pp->p_type == PT_INTERP) { 688 if (pp->p_filesz >= MAXPATHLEN) { 689 error = ENOEXEC; 690 goto bad; 691 } 692 interp = PNBUF_GET(); 693 interp[0] = '\0'; 694 if ((error = exec_read_from(l, epp->ep_vp, 695 pp->p_offset, interp, pp->p_filesz)) != 0) 696 goto bad; 697 break; 698 } 699 } 700 701 /* 702 * On the same architecture, we may be emulating different systems. 703 * See which one will accept this executable. 704 * 705 * Probe functions would normally see if the interpreter (if any) 706 * exists. Emulation packages may possibly replace the interpreter in 707 * interp[] with a changed path (/emul/xxx/<path>). 708 */ 709 pos = ELFDEFNNAME(NO_ADDR); 710 if (epp->ep_esch->u.elf_probe_func) { 711 vaddr_t startp = (vaddr_t)pos; 712 713 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 714 &startp); 715 if (error) 716 goto bad; 717 pos = (Elf_Addr)startp; 718 } 719 720 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 721 p->p_pax = epp->ep_pax_flags; 722 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 723 724 if (is_dyn) 725 elf_placedynexec(l, epp, eh, ph); 726 727 /* 728 * Load all the necessary sections 729 */ 730 for (i = nload = 0; i < eh->e_phnum; i++) { 731 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 732 u_long size = 0; 733 int prot = 0; 734 735 pp = &ph[i]; 736 737 switch (ph[i].p_type) { 738 case PT_LOAD: 739 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 740 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 741 742 /* 743 * Consider this as text segment, if it is executable. 744 * If there is more than one text segment, pick the 745 * largest. 746 */ 747 if (ph[i].p_flags & PF_X) { 748 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 749 size > epp->ep_tsize) { 750 epp->ep_taddr = addr; 751 epp->ep_tsize = size; 752 } 753 end_text = addr + size; 754 } else { 755 epp->ep_daddr = addr; 756 epp->ep_dsize = size; 757 } 758 if (ph[i].p_offset == 0) { 759 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 760 } 761 break; 762 763 case PT_SHLIB: 764 /* SCO has these sections. */ 765 case PT_INTERP: 766 /* Already did this one. */ 767 case PT_DYNAMIC: 768 break; 769 case PT_NOTE: 770 break; 771 case PT_PHDR: 772 /* Note address of program headers (in text segment) */ 773 phdr = pp->p_vaddr; 774 break; 775 776 default: 777 /* 778 * Not fatal; we don't need to understand everything. 779 */ 780 break; 781 } 782 } 783 if (interp || (epp->ep_flags & EXEC_FORCEAUX) != 0) { 784 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 785 ap->arg_interp = (vaddr_t)NULL; 786 } 787 788 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 789 epp->ep_daddr = round_page(end_text); 790 epp->ep_dsize = 0; 791 } 792 793 /* 794 * Check if we found a dynamically linked binary and arrange to load 795 * its interpreter 796 */ 797 if (interp) { 798 int j = epp->ep_vmcmds.evs_used; 799 u_long interp_offset; 800 801 if ((error = elf_load_file(l, epp, interp, 802 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 803 goto bad; 804 } 805 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 806 epp->ep_entry = ap->arg_interp + interp_offset; 807 PNBUF_PUT(interp); 808 } else 809 epp->ep_entry = eh->e_entry; 810 811 if (ap) { 812 ap->arg_phaddr = phdr ? phdr : computed_phdr; 813 ap->arg_phentsize = eh->e_phentsize; 814 ap->arg_phnum = eh->e_phnum; 815 ap->arg_entry = eh->e_entry; 816 epp->ep_emul_arg = ap; 817 } 818 819 #ifdef ELF_MAP_PAGE_ZERO 820 /* Dell SVR4 maps page zero, yeuch! */ 821 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 822 epp->ep_vp, 0, VM_PROT_READ); 823 #endif 824 kmem_free(ph, phsize); 825 return (*epp->ep_esch->es_setup_stack)(l, epp); 826 827 bad: 828 if (interp) 829 PNBUF_PUT(interp); 830 if (ap) 831 kmem_free(ap, sizeof(*ap)); 832 kmem_free(ph, phsize); 833 kill_vmcmds(&epp->ep_vmcmds); 834 return error; 835 } 836 837 int 838 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 839 Elf_Ehdr *eh) 840 { 841 size_t i; 842 Elf_Shdr *sh; 843 Elf_Nhdr *np; 844 size_t shsize; 845 int error; 846 int isnetbsd = 0; 847 char *ndata; 848 849 epp->ep_pax_flags = 0; 850 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 851 return ENOEXEC; 852 853 shsize = eh->e_shnum * sizeof(Elf_Shdr); 854 sh = kmem_alloc(shsize, KM_SLEEP); 855 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 856 if (error) 857 goto out; 858 859 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 860 for (i = 0; i < eh->e_shnum; i++) { 861 Elf_Shdr *shp = &sh[i]; 862 863 if (shp->sh_type != SHT_NOTE || 864 shp->sh_size > MAXNOTESIZE || 865 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 866 continue; 867 868 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 869 shp->sh_size); 870 if (error) 871 continue; 872 873 ndata = (char *)(np + 1); 874 switch (np->n_type) { 875 case ELF_NOTE_TYPE_NETBSD_TAG: 876 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 877 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 878 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 879 ELF_NOTE_NETBSD_NAMESZ)) 880 goto bad; 881 isnetbsd = 1; 882 break; 883 884 case ELF_NOTE_TYPE_PAX_TAG: 885 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 886 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 887 memcmp(ndata, ELF_NOTE_PAX_NAME, 888 ELF_NOTE_PAX_NAMESZ)) { 889 bad: 890 /* 891 * Ignore GNU tags 892 */ 893 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 894 memcmp(ndata, ELF_NOTE_GNU_NAME, 895 ELF_NOTE_GNU_NAMESZ) == 0) 896 break; 897 #ifdef DIAGNOSTIC 898 printf("%s: bad tag %d: " 899 "[%d %d, %d %d, %*.*s %*.*s]\n", 900 epp->ep_kname, 901 np->n_type, 902 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 903 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 904 ELF_NOTE_PAX_NAMESZ, 905 ELF_NOTE_PAX_NAMESZ, 906 ndata, 907 ELF_NOTE_PAX_NAMESZ, 908 ELF_NOTE_PAX_NAMESZ, 909 ELF_NOTE_PAX_NAME); 910 #endif 911 continue; 912 } 913 (void)memcpy(&epp->ep_pax_flags, 914 ndata + ELF_NOTE_PAX_NAMESZ, 915 sizeof(epp->ep_pax_flags)); 916 break; 917 918 case ELF_NOTE_TYPE_SUSE_TAG: 919 break; 920 921 default: 922 #ifdef DIAGNOSTIC 923 printf("%s: unknown note type %d\n", epp->ep_kname, 924 np->n_type); 925 #endif 926 break; 927 } 928 } 929 kmem_free(np, MAXNOTESIZE); 930 931 error = isnetbsd ? 0 : ENOEXEC; 932 out: 933 kmem_free(sh, shsize); 934 return error; 935 } 936 937 int 938 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 939 vaddr_t *pos) 940 { 941 int error; 942 943 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 944 return error; 945 #ifdef ELF_MD_PROBE_FUNC 946 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 947 return error; 948 #elif defined(ELF_INTERP_NON_RELOCATABLE) 949 *pos = ELF_LINK_ADDR; 950 #endif 951 epp->ep_flags |= EXEC_FORCEAUX; 952 return 0; 953 } 954
Indexes created Tue Sep 23 07:09:52 GMT 2025