exec_elf.c revision 1.33
1 /* $NetBSD: exec_elf.c,v 1.33 2011/11/19 22:51:25 tls 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 1.33 2011/11/19 22:51:25 tls 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 #include <sys/cprng.h> 81 82 #include <sys/cpu.h> 83 #include <machine/reg.h> 84 85 #include <compat/common/compat_util.h> 86 87 #include <sys/pax.h> 88 89 extern struct emul emul_netbsd; 90 91 #define elf_check_header ELFNAME(check_header) 92 #define elf_copyargs ELFNAME(copyargs) 93 #define elf_load_file ELFNAME(load_file) 94 #define elf_load_psection ELFNAME(load_psection) 95 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 96 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 97 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 98 #define coredump ELFNAMEEND(coredump) 99 100 int elf_load_file(struct lwp *, struct exec_package *, char *, 101 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); 102 void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, 103 const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); 104 105 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 106 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 107 vaddr_t *); 108 109 /* round up and down to page boundaries. */ 110 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 111 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 112 113 /* 114 * Arbitrary limits to avoid DoS for excessive memory allocation. 115 */ 116 #define MAXPHNUM 128 117 #define MAXSHNUM 32768 118 #define MAXNOTESIZE 1024 119 120 static void 121 elf_placedynexec(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 122 Elf_Phdr *ph) 123 { 124 Elf_Addr align, offset; 125 int i; 126 127 for (align = i = 0; i < eh->e_phnum; i++) 128 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 129 align = ph[i].p_align; 130 131 #ifdef PAX_ASLR 132 if (pax_aslr_active(l)) { 133 size_t pax_align, l2, delta; 134 uint32_t r; 135 136 pax_align = align; 137 138 r = cprng_fast32(); 139 140 if (pax_align == 0) 141 pax_align = PGSHIFT; 142 l2 = ilog2(pax_align); 143 delta = PAX_ASLR_DELTA(r, l2, PAX_ASLR_DELTA_EXEC_LEN); 144 offset = ELF_TRUNC(delta, pax_align) + PAGE_SIZE; 145 #ifdef PAX_ASLR_DEBUG 146 uprintf("r=0x%x l2=0x%zx PGSHIFT=0x%x Delta=0x%zx\n", r, l2, 147 PGSHIFT, delta); 148 uprintf("pax offset=0x%llx entry=0x%llx\n", 149 (unsigned long long)offset, 150 (unsigned long long)eh->e_entry); 151 #endif /* PAX_ASLR_DEBUG */ 152 } else 153 #endif /* PAX_ASLR */ 154 offset = MAX(align, PAGE_SIZE); 155 156 offset += epp->ep_vm_minaddr; 157 158 for (i = 0; i < eh->e_phnum; i++) 159 ph[i].p_vaddr += offset; 160 eh->e_entry += offset; 161 } 162 163 /* 164 * Copy arguments onto the stack in the normal way, but add some 165 * extra information in case of dynamic binding. 166 */ 167 int 168 elf_copyargs(struct lwp *l, struct exec_package *pack, 169 struct ps_strings *arginfo, char **stackp, void *argp) 170 { 171 size_t len, vlen; 172 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 173 struct elf_args *ap; 174 int error; 175 176 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 177 return error; 178 179 a = ai; 180 execname = NULL; 181 182 /* 183 * Push extra arguments on the stack needed by dynamically 184 * linked binaries 185 */ 186 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 187 struct vattr *vap = pack->ep_vap; 188 189 a->a_type = AT_PHDR; 190 a->a_v = ap->arg_phaddr; 191 a++; 192 193 a->a_type = AT_PHENT; 194 a->a_v = ap->arg_phentsize; 195 a++; 196 197 a->a_type = AT_PHNUM; 198 a->a_v = ap->arg_phnum; 199 a++; 200 201 a->a_type = AT_PAGESZ; 202 a->a_v = PAGE_SIZE; 203 a++; 204 205 a->a_type = AT_BASE; 206 a->a_v = ap->arg_interp; 207 a++; 208 209 a->a_type = AT_FLAGS; 210 a->a_v = 0; 211 a++; 212 213 a->a_type = AT_ENTRY; 214 a->a_v = ap->arg_entry; 215 a++; 216 217 a->a_type = AT_EUID; 218 if (vap->va_mode & S_ISUID) 219 a->a_v = vap->va_uid; 220 else 221 a->a_v = kauth_cred_geteuid(l->l_cred); 222 a++; 223 224 a->a_type = AT_RUID; 225 a->a_v = kauth_cred_getuid(l->l_cred); 226 a++; 227 228 a->a_type = AT_EGID; 229 if (vap->va_mode & S_ISGID) 230 a->a_v = vap->va_gid; 231 else 232 a->a_v = kauth_cred_getegid(l->l_cred); 233 a++; 234 235 a->a_type = AT_RGID; 236 a->a_v = kauth_cred_getgid(l->l_cred); 237 a++; 238 239 if (pack->ep_path) { 240 execname = a; 241 a->a_type = AT_SUN_EXECNAME; 242 a++; 243 } 244 245 free(ap, M_TEMP); 246 pack->ep_emul_arg = NULL; 247 } 248 249 a->a_type = AT_NULL; 250 a->a_v = 0; 251 a++; 252 253 vlen = (a - ai) * sizeof(AuxInfo); 254 255 if (execname) { 256 char *path = pack->ep_path; 257 execname->a_v = (uintptr_t)(*stackp + vlen); 258 len = strlen(path) + 1; 259 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 260 return error; 261 len = ALIGN(len); 262 } else 263 len = 0; 264 265 if ((error = copyout(ai, *stackp, vlen)) != 0) 266 return error; 267 *stackp += vlen + len; 268 269 return 0; 270 } 271 272 /* 273 * elf_check_header(): 274 * 275 * Check header for validity; return 0 of ok ENOEXEC if error 276 */ 277 int 278 elf_check_header(Elf_Ehdr *eh, int type) 279 { 280 281 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 282 eh->e_ident[EI_CLASS] != ELFCLASS) 283 return ENOEXEC; 284 285 switch (eh->e_machine) { 286 287 ELFDEFNNAME(MACHDEP_ID_CASES) 288 289 default: 290 return ENOEXEC; 291 } 292 293 if (ELF_EHDR_FLAGS_OK(eh) == 0) 294 return ENOEXEC; 295 296 if (eh->e_type != type) 297 return ENOEXEC; 298 299 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 300 return ENOEXEC; 301 302 return 0; 303 } 304 305 /* 306 * elf_load_psection(): 307 * 308 * Load a psection at the appropriate address 309 */ 310 void 311 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 312 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 313 { 314 u_long msize, psize, rm, rf; 315 long diff, offset; 316 317 /* 318 * If the user specified an address, then we load there. 319 */ 320 if (*addr == ELFDEFNNAME(NO_ADDR)) 321 *addr = ph->p_vaddr; 322 323 if (ph->p_align > 1) { 324 /* 325 * Make sure we are virtually aligned as we are supposed to be. 326 */ 327 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 328 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 329 /* 330 * But make sure to not map any pages before the start of the 331 * psection by limiting the difference to within a page. 332 */ 333 diff &= PAGE_MASK; 334 } else 335 diff = 0; 336 337 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 338 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 339 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 340 341 /* 342 * Adjust everything so it all starts on a page boundary. 343 */ 344 *addr -= diff; 345 offset = ph->p_offset - diff; 346 *size = ph->p_filesz + diff; 347 msize = ph->p_memsz + diff; 348 349 if (ph->p_align >= PAGE_SIZE) { 350 if ((ph->p_flags & PF_W) != 0) { 351 /* 352 * Because the pagedvn pager can't handle zero fill 353 * of the last data page if it's not page aligned we 354 * map the last page readvn. 355 */ 356 psize = trunc_page(*size); 357 } else { 358 psize = round_page(*size); 359 } 360 } else { 361 psize = *size; 362 } 363 364 if (psize > 0) { 365 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 366 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 367 offset, *prot, flags); 368 flags &= VMCMD_RELATIVE; 369 } 370 if (psize < *size) { 371 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 372 *addr + psize, vp, offset + psize, *prot, flags); 373 } 374 375 /* 376 * Check if we need to extend the size of the segment (does 377 * bss extend page the next page boundary)? 378 */ 379 rm = round_page(*addr + msize); 380 rf = round_page(*addr + *size); 381 382 if (rm != rf) { 383 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 384 0, *prot, flags & VMCMD_RELATIVE); 385 *size = msize; 386 } 387 } 388 389 /* 390 * elf_load_file(): 391 * 392 * Load a file (interpreter/library) pointed to by path 393 * [stolen from coff_load_shlib()]. Made slightly generic 394 * so it might be used externally. 395 */ 396 int 397 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 398 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 399 Elf_Addr *last) 400 { 401 int error, i; 402 struct vnode *vp; 403 struct vattr attr; 404 Elf_Ehdr eh; 405 Elf_Phdr *ph = NULL; 406 const Elf_Phdr *ph0; 407 const Elf_Phdr *base_ph; 408 const Elf_Phdr *last_ph; 409 u_long phsize; 410 Elf_Addr addr = *last; 411 struct proc *p; 412 413 p = l->l_proc; 414 415 /* 416 * 1. open file 417 * 2. read filehdr 418 * 3. map text, data, and bss out of it using VM_* 419 */ 420 vp = epp->ep_interp; 421 if (vp == NULL) { 422 error = emul_find_interp(l, epp, path); 423 if (error != 0) 424 return error; 425 vp = epp->ep_interp; 426 } 427 /* We'll tidy this ourselves - otherwise we have locking issues */ 428 epp->ep_interp = NULL; 429 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 430 431 /* 432 * Similarly, if it's not marked as executable, or it's not a regular 433 * file, we don't allow it to be used. 434 */ 435 if (vp->v_type != VREG) { 436 error = EACCES; 437 goto badunlock; 438 } 439 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 440 goto badunlock; 441 442 /* get attributes */ 443 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 444 goto badunlock; 445 446 /* 447 * Check mount point. Though we're not trying to exec this binary, 448 * we will be executing code from it, so if the mount point 449 * disallows execution or set-id-ness, we punt or kill the set-id. 450 */ 451 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 452 error = EACCES; 453 goto badunlock; 454 } 455 if (vp->v_mount->mnt_flag & MNT_NOSUID) 456 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 457 458 #ifdef notyet /* XXX cgd 960926 */ 459 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 460 461 XXXps: this problem will make it impossible to use an interpreter 462 from a file system which actually does something in VOP_OPEN 463 #endif 464 465 error = vn_marktext(vp); 466 if (error) 467 goto badunlock; 468 469 VOP_UNLOCK(vp); 470 471 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 472 goto bad; 473 474 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 475 goto bad; 476 477 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 478 error = ENOEXEC; 479 goto bad; 480 } 481 482 phsize = eh.e_phnum * sizeof(Elf_Phdr); 483 ph = kmem_alloc(phsize, KM_SLEEP); 484 485 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 486 goto bad; 487 488 #ifdef ELF_INTERP_NON_RELOCATABLE 489 /* 490 * Evil hack: Only MIPS should be non-relocatable, and the 491 * psections should have a high address (typically 0x5ffe0000). 492 * If it's now relocatable, it should be linked at 0 and the 493 * psections should have zeros in the upper part of the address. 494 * Otherwise, force the load at the linked address. 495 */ 496 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 497 *last = ELFDEFNNAME(NO_ADDR); 498 #endif 499 500 /* 501 * If no position to load the interpreter was set by a probe 502 * function, pick the same address that a non-fixed mmap(0, ..) 503 * would (i.e. something safely out of the way). 504 */ 505 if (*last == ELFDEFNNAME(NO_ADDR)) { 506 u_long limit = 0; 507 /* 508 * Find the start and ending addresses of the psections to 509 * be loaded. This will give us the size. 510 */ 511 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 512 i++, ph0++) { 513 if (ph0->p_type == PT_LOAD) { 514 u_long psize = ph0->p_vaddr + ph0->p_memsz; 515 if (base_ph == NULL) 516 base_ph = ph0; 517 if (psize > limit) 518 limit = psize; 519 } 520 } 521 522 if (base_ph == NULL) { 523 error = ENOEXEC; 524 goto bad; 525 } 526 527 /* 528 * Now compute the size and load address. 529 */ 530 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 531 epp->ep_daddr, 532 round_page(limit) - trunc_page(base_ph->p_vaddr)); 533 } else 534 addr = *last; /* may be ELF_LINK_ADDR */ 535 536 /* 537 * Load all the necessary sections 538 */ 539 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 540 i < eh.e_phnum; i++, ph0++) { 541 switch (ph0->p_type) { 542 case PT_LOAD: { 543 u_long size; 544 int prot = 0; 545 int flags; 546 547 if (base_ph == NULL) { 548 /* 549 * First encountered psection is always the 550 * base psection. Make sure it's aligned 551 * properly (align down for topdown and align 552 * upwards for not topdown). 553 */ 554 base_ph = ph0; 555 flags = VMCMD_BASE; 556 if (addr == ELF_LINK_ADDR) 557 addr = ph0->p_vaddr; 558 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 559 addr = ELF_TRUNC(addr, ph0->p_align); 560 else 561 addr = ELF_ROUND(addr, ph0->p_align); 562 } else { 563 u_long limit = round_page(last_ph->p_vaddr 564 + last_ph->p_memsz); 565 u_long base = trunc_page(ph0->p_vaddr); 566 567 /* 568 * If there is a gap in between the psections, 569 * map it as inaccessible so nothing else 570 * mmap'ed will be placed there. 571 */ 572 if (limit != base) { 573 NEW_VMCMD2(vcset, vmcmd_map_zero, 574 base - limit, 575 limit - base_ph->p_vaddr, NULLVP, 576 0, VM_PROT_NONE, VMCMD_RELATIVE); 577 } 578 579 addr = ph0->p_vaddr - base_ph->p_vaddr; 580 flags = VMCMD_RELATIVE; 581 } 582 last_ph = ph0; 583 elf_load_psection(vcset, vp, &ph[i], &addr, 584 &size, &prot, flags); 585 /* 586 * If entry is within this psection then this 587 * must contain the .text section. *entryoff is 588 * relative to the base psection. 589 */ 590 if (eh.e_entry >= ph0->p_vaddr && 591 eh.e_entry < (ph0->p_vaddr + size)) { 592 *entryoff = eh.e_entry - base_ph->p_vaddr; 593 } 594 addr += size; 595 break; 596 } 597 598 case PT_DYNAMIC: 599 case PT_PHDR: 600 break; 601 602 case PT_NOTE: 603 break; 604 605 default: 606 break; 607 } 608 } 609 610 kmem_free(ph, phsize); 611 /* 612 * This value is ignored if TOPDOWN. 613 */ 614 *last = addr; 615 vrele(vp); 616 return 0; 617 618 badunlock: 619 VOP_UNLOCK(vp); 620 621 bad: 622 if (ph != NULL) 623 kmem_free(ph, phsize); 624 #ifdef notyet /* XXX cgd 960926 */ 625 (maybe) VOP_CLOSE it 626 #endif 627 vrele(vp); 628 return error; 629 } 630 631 /* 632 * exec_elf_makecmds(): Prepare an Elf binary's exec package 633 * 634 * First, set of the various offsets/lengths in the exec package. 635 * 636 * Then, mark the text image busy (so it can be demand paged) or error 637 * out if this is not possible. Finally, set up vmcmds for the 638 * text, data, bss, and stack segments. 639 */ 640 int 641 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 642 { 643 Elf_Ehdr *eh = epp->ep_hdr; 644 Elf_Phdr *ph, *pp; 645 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 646 int error, i, nload; 647 char *interp = NULL; 648 u_long phsize; 649 struct proc *p; 650 struct elf_args *ap = NULL; 651 bool is_dyn; 652 653 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 654 return ENOEXEC; 655 656 is_dyn = elf_check_header(eh, ET_DYN) == 0; 657 /* 658 * XXX allow for executing shared objects. It seems silly 659 * but other ELF-based systems allow it as well. 660 */ 661 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 662 return ENOEXEC; 663 664 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 665 return ENOEXEC; 666 667 error = vn_marktext(epp->ep_vp); 668 if (error) 669 return error; 670 671 /* 672 * Allocate space to hold all the program headers, and read them 673 * from the file 674 */ 675 p = l->l_proc; 676 phsize = eh->e_phnum * sizeof(Elf_Phdr); 677 ph = kmem_alloc(phsize, KM_SLEEP); 678 679 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 680 0) 681 goto bad; 682 683 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 684 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 685 686 for (i = 0; i < eh->e_phnum; i++) { 687 pp = &ph[i]; 688 if (pp->p_type == PT_INTERP) { 689 if (pp->p_filesz >= MAXPATHLEN) { 690 error = ENOEXEC; 691 goto bad; 692 } 693 interp = PNBUF_GET(); 694 interp[0] = '\0'; 695 if ((error = exec_read_from(l, epp->ep_vp, 696 pp->p_offset, interp, pp->p_filesz)) != 0) 697 goto bad; 698 break; 699 } 700 } 701 702 /* 703 * On the same architecture, we may be emulating different systems. 704 * See which one will accept this executable. 705 * 706 * Probe functions would normally see if the interpreter (if any) 707 * exists. Emulation packages may possibly replace the interpreter in 708 * interp[] with a changed path (/emul/xxx/<path>). 709 */ 710 pos = ELFDEFNNAME(NO_ADDR); 711 if (epp->ep_esch->u.elf_probe_func) { 712 vaddr_t startp = (vaddr_t)pos; 713 714 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 715 &startp); 716 if (error) 717 goto bad; 718 pos = (Elf_Addr)startp; 719 } 720 721 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 722 p->p_pax = epp->ep_pax_flags; 723 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 724 725 if (is_dyn) 726 elf_placedynexec(l, epp, eh, ph); 727 728 /* 729 * Load all the necessary sections 730 */ 731 for (i = nload = 0; i < eh->e_phnum; i++) { 732 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 733 u_long size = 0; 734 int prot = 0; 735 736 pp = &ph[i]; 737 738 switch (ph[i].p_type) { 739 case PT_LOAD: 740 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 741 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 742 743 /* 744 * Consider this as text segment, if it is executable. 745 * If there is more than one text segment, pick the 746 * largest. 747 */ 748 if (ph[i].p_flags & PF_X) { 749 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 750 size > epp->ep_tsize) { 751 epp->ep_taddr = addr; 752 epp->ep_tsize = size; 753 } 754 end_text = addr + size; 755 } else { 756 epp->ep_daddr = addr; 757 epp->ep_dsize = size; 758 } 759 if (ph[i].p_offset == 0) { 760 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 761 } 762 break; 763 764 case PT_SHLIB: 765 /* SCO has these sections. */ 766 case PT_INTERP: 767 /* Already did this one. */ 768 case PT_DYNAMIC: 769 break; 770 case PT_NOTE: 771 break; 772 case PT_PHDR: 773 /* Note address of program headers (in text segment) */ 774 phdr = pp->p_vaddr; 775 break; 776 777 default: 778 /* 779 * Not fatal; we don't need to understand everything. 780 */ 781 break; 782 } 783 } 784 if (interp || (epp->ep_flags & EXEC_FORCEAUX) != 0) { 785 ap = malloc(sizeof(struct elf_args), M_TEMP, M_WAITOK); 786 ap->arg_interp = (vaddr_t)NULL; 787 } 788 789 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 790 epp->ep_daddr = round_page(end_text); 791 epp->ep_dsize = 0; 792 } 793 794 /* 795 * Check if we found a dynamically linked binary and arrange to load 796 * its interpreter 797 */ 798 if (interp) { 799 int j = epp->ep_vmcmds.evs_used; 800 u_long interp_offset; 801 802 if ((error = elf_load_file(l, epp, interp, 803 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 804 goto bad; 805 } 806 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 807 epp->ep_entry = ap->arg_interp + interp_offset; 808 PNBUF_PUT(interp); 809 } else 810 epp->ep_entry = eh->e_entry; 811 812 if (ap) { 813 ap->arg_phaddr = phdr ? phdr : computed_phdr; 814 ap->arg_phentsize = eh->e_phentsize; 815 ap->arg_phnum = eh->e_phnum; 816 ap->arg_entry = eh->e_entry; 817 epp->ep_emul_arg = ap; 818 } 819 820 #ifdef ELF_MAP_PAGE_ZERO 821 /* Dell SVR4 maps page zero, yeuch! */ 822 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 823 epp->ep_vp, 0, VM_PROT_READ); 824 #endif 825 kmem_free(ph, phsize); 826 return (*epp->ep_esch->es_setup_stack)(l, epp); 827 828 bad: 829 if (interp) 830 PNBUF_PUT(interp); 831 if (ap) 832 free(ap, M_TEMP); 833 kmem_free(ph, phsize); 834 kill_vmcmds(&epp->ep_vmcmds); 835 return error; 836 } 837 838 int 839 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 840 Elf_Ehdr *eh) 841 { 842 size_t i; 843 Elf_Shdr *sh; 844 Elf_Nhdr *np; 845 size_t shsize; 846 int error; 847 int isnetbsd = 0; 848 char *ndata; 849 850 epp->ep_pax_flags = 0; 851 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 852 return ENOEXEC; 853 854 shsize = eh->e_shnum * sizeof(Elf_Shdr); 855 sh = kmem_alloc(shsize, KM_SLEEP); 856 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 857 if (error) 858 goto out; 859 860 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 861 for (i = 0; i < eh->e_shnum; i++) { 862 Elf_Shdr *shp = &sh[i]; 863 864 if (shp->sh_type != SHT_NOTE || 865 shp->sh_size > MAXNOTESIZE || 866 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 867 continue; 868 869 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 870 shp->sh_size); 871 if (error) 872 continue; 873 874 ndata = (char *)(np + 1); 875 switch (np->n_type) { 876 case ELF_NOTE_TYPE_NETBSD_TAG: 877 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 878 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 879 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 880 ELF_NOTE_NETBSD_NAMESZ)) 881 goto bad; 882 isnetbsd = 1; 883 break; 884 885 case ELF_NOTE_TYPE_PAX_TAG: 886 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 887 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 888 memcmp(ndata, ELF_NOTE_PAX_NAME, 889 ELF_NOTE_PAX_NAMESZ)) { 890 bad: 891 /* 892 * Ignore GNU tags 893 */ 894 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 895 memcmp(ndata, ELF_NOTE_GNU_NAME, 896 ELF_NOTE_GNU_NAMESZ) == 0) 897 break; 898 #ifdef DIAGNOSTIC 899 printf("%s: bad tag %d: " 900 "[%d %d, %d %d, %*.*s %*.*s]\n", 901 epp->ep_kname, 902 np->n_type, 903 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 904 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 905 ELF_NOTE_PAX_NAMESZ, 906 ELF_NOTE_PAX_NAMESZ, 907 ndata, 908 ELF_NOTE_PAX_NAMESZ, 909 ELF_NOTE_PAX_NAMESZ, 910 ELF_NOTE_PAX_NAME); 911 #endif 912 continue; 913 } 914 (void)memcpy(&epp->ep_pax_flags, 915 ndata + ELF_NOTE_PAX_NAMESZ, 916 sizeof(epp->ep_pax_flags)); 917 break; 918 919 case ELF_NOTE_TYPE_SUSE_TAG: 920 break; 921 922 default: 923 #ifdef DIAGNOSTIC 924 printf("%s: unknown note type %d\n", epp->ep_kname, 925 np->n_type); 926 #endif 927 break; 928 } 929 } 930 kmem_free(np, MAXNOTESIZE); 931 932 error = isnetbsd ? 0 : ENOEXEC; 933 out: 934 kmem_free(sh, shsize); 935 return error; 936 } 937 938 int 939 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 940 vaddr_t *pos) 941 { 942 int error; 943 944 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 945 return error; 946 #ifdef ELF_MD_PROBE_FUNC 947 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 948 return error; 949 #elif defined(ELF_INTERP_NON_RELOCATABLE) 950 *pos = ELF_LINK_ADDR; 951 #endif 952 epp->ep_flags |= EXEC_FORCEAUX; 953 return 0; 954 } 955
Indexes created Mon Sep 22 21:09:42 GMT 2025