exec_elf.c revision 1.13.2.3
1 /* $NetBSD: exec_elf.c,v 1.13.2.3 2011/03/05 20:55:12 rmind 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 1.13.2.3 2011/03/05 20:55:12 rmind Exp $"); 61 62 #ifdef _KERNEL_OPT 63 #include "opt_pax.h" 64 #endif /* _KERNEL_OPT */ 65 66 #include <sys/param.h> 67 #include <sys/proc.h> 68 #include <sys/malloc.h> 69 #include <sys/kmem.h> 70 #include <sys/namei.h> 71 #include <sys/vnode.h> 72 #include <sys/exec.h> 73 #include <sys/exec_elf.h> 74 #include <sys/syscall.h> 75 #include <sys/signalvar.h> 76 #include <sys/mount.h> 77 #include <sys/stat.h> 78 #include <sys/kauth.h> 79 #include <sys/bitops.h> 80 81 #include <sys/cpu.h> 82 #include <machine/reg.h> 83 84 #include <compat/common/compat_util.h> 85 86 #include <sys/pax.h> 87 88 extern struct emul emul_netbsd; 89 90 #define elf_check_header ELFNAME(check_header) 91 #define elf_copyargs ELFNAME(copyargs) 92 #define elf_load_file ELFNAME(load_file) 93 #define elf_load_psection ELFNAME(load_psection) 94 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 95 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 96 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 97 #define coredump ELFNAMEEND(coredump) 98 99 int elf_load_file(struct lwp *, struct exec_package *, char *, 100 struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); 101 void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, 102 const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); 103 104 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 105 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 106 vaddr_t *); 107 108 /* round up and down to page boundaries. */ 109 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 110 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 111 112 /* 113 * Arbitrary limits to avoid DoS for excessive memory allocation. 114 */ 115 #define MAXPHNUM 128 116 #define MAXSHNUM 32768 117 #define MAXNOTESIZE 1024 118 119 static void 120 elf_placedynexec(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, 121 Elf_Phdr *ph) 122 { 123 Elf_Addr align, offset; 124 int i; 125 126 for (align = i = 0; i < eh->e_phnum; i++) 127 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 128 align = ph[i].p_align; 129 130 #ifdef PAX_ASLR 131 if (pax_aslr_active(l)) { 132 size_t pax_align, l2, delta; 133 uint32_t r; 134 135 pax_align = align; 136 137 r = arc4random(); 138 139 if (pax_align == 0) 140 pax_align = PGSHIFT; 141 l2 = ilog2(pax_align); 142 delta = PAX_ASLR_DELTA(r, l2, PAX_ASLR_DELTA_EXEC_LEN); 143 offset = ELF_TRUNC(delta, pax_align) + PAGE_SIZE; 144 #ifdef PAX_ASLR_DEBUG 145 uprintf("r=0x%x l2=0x%zx PGSHIFT=0x%x Delta=0x%zx\n", r, l2, 146 PGSHIFT, delta); 147 uprintf("pax offset=0x%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 for (i = 0; i < eh->e_phnum; i++) 156 ph[i].p_vaddr += offset; 157 eh->e_entry += offset; 158 } 159 160 /* 161 * Copy arguments onto the stack in the normal way, but add some 162 * extra information in case of dynamic binding. 163 */ 164 int 165 elf_copyargs(struct lwp *l, struct exec_package *pack, 166 struct ps_strings *arginfo, char **stackp, void *argp) 167 { 168 size_t len, vlen; 169 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 170 struct elf_args *ap; 171 int error; 172 173 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 174 return error; 175 176 a = ai; 177 execname = NULL; 178 179 /* 180 * Push extra arguments on the stack needed by dynamically 181 * linked binaries 182 */ 183 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 184 struct vattr *vap = pack->ep_vap; 185 186 a->a_type = AT_PHDR; 187 a->a_v = ap->arg_phaddr; 188 a++; 189 190 a->a_type = AT_PHENT; 191 a->a_v = ap->arg_phentsize; 192 a++; 193 194 a->a_type = AT_PHNUM; 195 a->a_v = ap->arg_phnum; 196 a++; 197 198 a->a_type = AT_PAGESZ; 199 a->a_v = PAGE_SIZE; 200 a++; 201 202 a->a_type = AT_BASE; 203 a->a_v = ap->arg_interp; 204 a++; 205 206 a->a_type = AT_FLAGS; 207 a->a_v = 0; 208 a++; 209 210 a->a_type = AT_ENTRY; 211 a->a_v = ap->arg_entry; 212 a++; 213 214 a->a_type = AT_EUID; 215 if (vap->va_mode & S_ISUID) 216 a->a_v = vap->va_uid; 217 else 218 a->a_v = kauth_cred_geteuid(l->l_cred); 219 a++; 220 221 a->a_type = AT_RUID; 222 a->a_v = kauth_cred_getuid(l->l_cred); 223 a++; 224 225 a->a_type = AT_EGID; 226 if (vap->va_mode & S_ISGID) 227 a->a_v = vap->va_gid; 228 else 229 a->a_v = kauth_cred_getegid(l->l_cred); 230 a++; 231 232 a->a_type = AT_RGID; 233 a->a_v = kauth_cred_getgid(l->l_cred); 234 a++; 235 236 if (pack->ep_path) { 237 execname = a; 238 a->a_type = AT_SUN_EXECNAME; 239 a++; 240 } 241 242 free(ap, M_TEMP); 243 pack->ep_emul_arg = NULL; 244 } 245 246 a->a_type = AT_NULL; 247 a->a_v = 0; 248 a++; 249 250 vlen = (a - ai) * sizeof(AuxInfo); 251 252 if (execname) { 253 char *path = pack->ep_path; 254 execname->a_v = (uintptr_t)(*stackp + vlen); 255 len = strlen(path) + 1; 256 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 257 return error; 258 len = ALIGN(len); 259 } else 260 len = 0; 261 262 if ((error = copyout(ai, *stackp, vlen)) != 0) 263 return error; 264 *stackp += vlen + len; 265 266 return 0; 267 } 268 269 /* 270 * elf_check_header(): 271 * 272 * Check header for validity; return 0 of ok ENOEXEC if error 273 */ 274 int 275 elf_check_header(Elf_Ehdr *eh, int type) 276 { 277 278 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 279 eh->e_ident[EI_CLASS] != ELFCLASS) 280 return ENOEXEC; 281 282 switch (eh->e_machine) { 283 284 ELFDEFNNAME(MACHDEP_ID_CASES) 285 286 default: 287 return ENOEXEC; 288 } 289 290 if (ELF_EHDR_FLAGS_OK(eh) == 0) 291 return ENOEXEC; 292 293 if (eh->e_type != type) 294 return ENOEXEC; 295 296 if (eh->e_shnum > MAXSHNUM || eh->e_phnum > MAXPHNUM) 297 return ENOEXEC; 298 299 return 0; 300 } 301 302 /* 303 * elf_load_psection(): 304 * 305 * Load a psection at the appropriate address 306 */ 307 void 308 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 309 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) 310 { 311 u_long msize, psize, rm, rf; 312 long diff, offset; 313 314 /* 315 * If the user specified an address, then we load there. 316 */ 317 if (*addr == ELFDEFNNAME(NO_ADDR)) 318 *addr = ph->p_vaddr; 319 320 if (ph->p_align > 1) { 321 /* 322 * Make sure we are virtually aligned as we are supposed to be. 323 */ 324 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 325 KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); 326 /* 327 * But make sure to not map any pages before the start of the 328 * psection by limiting the difference to within a page. 329 */ 330 diff &= PAGE_MASK; 331 } else 332 diff = 0; 333 334 *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 335 *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 336 *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 337 338 /* 339 * Adjust everything so it all starts on a page boundary. 340 */ 341 *addr -= diff; 342 offset = ph->p_offset - diff; 343 *size = ph->p_filesz + diff; 344 msize = ph->p_memsz + diff; 345 346 if (ph->p_align >= PAGE_SIZE) { 347 if ((ph->p_flags & PF_W) != 0) { 348 /* 349 * Because the pagedvn pager can't handle zero fill 350 * of the last data page if it's not page aligned we 351 * map the last page readvn. 352 */ 353 psize = trunc_page(*size); 354 } else { 355 psize = round_page(*size); 356 } 357 } else { 358 psize = *size; 359 } 360 361 if (psize > 0) { 362 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 363 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 364 offset, *prot, flags); 365 flags &= VMCMD_RELATIVE; 366 } 367 if (psize < *size) { 368 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 369 *addr + psize, vp, offset + psize, *prot, flags); 370 } 371 372 /* 373 * Check if we need to extend the size of the segment (does 374 * bss extend page the next page boundary)? 375 */ 376 rm = round_page(*addr + msize); 377 rf = round_page(*addr + *size); 378 379 if (rm != rf) { 380 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 381 0, *prot, flags & VMCMD_RELATIVE); 382 *size = msize; 383 } 384 } 385 386 /* 387 * elf_load_file(): 388 * 389 * Load a file (interpreter/library) pointed to by path 390 * [stolen from coff_load_shlib()]. Made slightly generic 391 * so it might be used externally. 392 */ 393 int 394 elf_load_file(struct lwp *l, struct exec_package *epp, char *path, 395 struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap, 396 Elf_Addr *last) 397 { 398 int error, i; 399 struct vnode *vp; 400 struct vattr attr; 401 Elf_Ehdr eh; 402 Elf_Phdr *ph = NULL; 403 const Elf_Phdr *ph0; 404 const Elf_Phdr *base_ph; 405 const Elf_Phdr *last_ph; 406 u_long phsize; 407 Elf_Addr addr = *last; 408 struct proc *p; 409 410 p = l->l_proc; 411 412 /* 413 * 1. open file 414 * 2. read filehdr 415 * 3. map text, data, and bss out of it using VM_* 416 */ 417 vp = epp->ep_interp; 418 if (vp == NULL) { 419 error = emul_find_interp(l, epp, path); 420 if (error != 0) 421 return error; 422 vp = epp->ep_interp; 423 } 424 /* We'll tidy this ourselves - otherwise we have locking issues */ 425 epp->ep_interp = NULL; 426 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 427 428 /* 429 * Similarly, if it's not marked as executable, or it's not a regular 430 * file, we don't allow it to be used. 431 */ 432 if (vp->v_type != VREG) { 433 error = EACCES; 434 goto badunlock; 435 } 436 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 437 goto badunlock; 438 439 /* get attributes */ 440 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 441 goto badunlock; 442 443 /* 444 * Check mount point. Though we're not trying to exec this binary, 445 * we will be executing code from it, so if the mount point 446 * disallows execution or set-id-ness, we punt or kill the set-id. 447 */ 448 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 449 error = EACCES; 450 goto badunlock; 451 } 452 if (vp->v_mount->mnt_flag & MNT_NOSUID) 453 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 454 455 #ifdef notyet /* XXX cgd 960926 */ 456 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 457 458 XXXps: this problem will make it impossible to use an interpreter 459 from a file system which actually does something in VOP_OPEN 460 #endif 461 462 error = vn_marktext(vp); 463 if (error) 464 goto badunlock; 465 466 VOP_UNLOCK(vp); 467 468 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 469 goto bad; 470 471 if ((error = elf_check_header(&eh, ET_DYN)) != 0) 472 goto bad; 473 474 if (eh.e_phnum > MAXPHNUM || eh.e_phnum == 0) { 475 error = ENOEXEC; 476 goto bad; 477 } 478 479 phsize = eh.e_phnum * sizeof(Elf_Phdr); 480 ph = kmem_alloc(phsize, KM_SLEEP); 481 482 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 483 goto bad; 484 485 #ifdef ELF_INTERP_NON_RELOCATABLE 486 /* 487 * Evil hack: Only MIPS should be non-relocatable, and the 488 * psections should have a high address (typically 0x5ffe0000). 489 * If it's now relocatable, it should be linked at 0 and the 490 * psections should have zeros in the upper part of the address. 491 * Otherwise, force the load at the linked address. 492 */ 493 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 494 *last = ELFDEFNNAME(NO_ADDR); 495 #endif 496 497 /* 498 * If no position to load the interpreter was set by a probe 499 * function, pick the same address that a non-fixed mmap(0, ..) 500 * would (i.e. something safely out of the way). 501 */ 502 if (*last == ELFDEFNNAME(NO_ADDR)) { 503 u_long limit = 0; 504 /* 505 * Find the start and ending addresses of the psections to 506 * be loaded. This will give us the size. 507 */ 508 for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; 509 i++, ph0++) { 510 if (ph0->p_type == PT_LOAD) { 511 u_long psize = ph0->p_vaddr + ph0->p_memsz; 512 if (base_ph == NULL) 513 base_ph = ph0; 514 if (psize > limit) 515 limit = psize; 516 } 517 } 518 519 if (base_ph == NULL) { 520 error = ENOEXEC; 521 goto bad; 522 } 523 524 /* 525 * Now compute the size and load address. 526 */ 527 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 528 epp->ep_daddr, 529 round_page(limit) - trunc_page(base_ph->p_vaddr)); 530 } else 531 addr = *last; /* may be ELF_LINK_ADDR */ 532 533 /* 534 * Load all the necessary sections 535 */ 536 for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; 537 i < eh.e_phnum; i++, ph0++) { 538 switch (ph0->p_type) { 539 case PT_LOAD: { 540 u_long size; 541 int prot = 0; 542 int flags; 543 544 if (base_ph == NULL) { 545 /* 546 * First encountered psection is always the 547 * base psection. Make sure it's aligned 548 * properly (align down for topdown and align 549 * upwards for not topdown). 550 */ 551 base_ph = ph0; 552 flags = VMCMD_BASE; 553 if (addr == ELF_LINK_ADDR) 554 addr = ph0->p_vaddr; 555 if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) 556 addr = ELF_TRUNC(addr, ph0->p_align); 557 else 558 addr = ELF_ROUND(addr, ph0->p_align); 559 } else { 560 u_long limit = round_page(last_ph->p_vaddr 561 + last_ph->p_memsz); 562 u_long base = trunc_page(ph0->p_vaddr); 563 564 /* 565 * If there is a gap in between the psections, 566 * map it as inaccessible so nothing else 567 * mmap'ed will be placed there. 568 */ 569 if (limit != base) { 570 NEW_VMCMD2(vcset, vmcmd_map_zero, 571 base - limit, 572 limit - base_ph->p_vaddr, NULLVP, 573 0, VM_PROT_NONE, VMCMD_RELATIVE); 574 } 575 576 addr = ph0->p_vaddr - base_ph->p_vaddr; 577 flags = VMCMD_RELATIVE; 578 } 579 last_ph = ph0; 580 elf_load_psection(vcset, vp, &ph[i], &addr, 581 &size, &prot, flags); 582 /* 583 * If entry is within this psection then this 584 * must contain the .text section. *entryoff is 585 * relative to the base psection. 586 */ 587 if (eh.e_entry >= ph0->p_vaddr && 588 eh.e_entry < (ph0->p_vaddr + size)) { 589 *entryoff = eh.e_entry - base_ph->p_vaddr; 590 } 591 addr += size; 592 break; 593 } 594 595 case PT_DYNAMIC: 596 case PT_PHDR: 597 break; 598 599 case PT_NOTE: 600 break; 601 602 default: 603 break; 604 } 605 } 606 607 kmem_free(ph, phsize); 608 /* 609 * This value is ignored if TOPDOWN. 610 */ 611 *last = addr; 612 vrele(vp); 613 return 0; 614 615 badunlock: 616 VOP_UNLOCK(vp); 617 618 bad: 619 if (ph != NULL) 620 kmem_free(ph, phsize); 621 #ifdef notyet /* XXX cgd 960926 */ 622 (maybe) VOP_CLOSE it 623 #endif 624 vrele(vp); 625 return error; 626 } 627 628 /* 629 * exec_elf_makecmds(): Prepare an Elf binary's exec package 630 * 631 * First, set of the various offsets/lengths in the exec package. 632 * 633 * Then, mark the text image busy (so it can be demand paged) or error 634 * out if this is not possible. Finally, set up vmcmds for the 635 * text, data, bss, and stack segments. 636 */ 637 int 638 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 639 { 640 Elf_Ehdr *eh = epp->ep_hdr; 641 Elf_Phdr *ph, *pp; 642 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 643 int error, i, nload; 644 char *interp = NULL; 645 u_long phsize; 646 struct proc *p; 647 struct elf_args *ap = NULL; 648 bool is_dyn; 649 650 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 651 return ENOEXEC; 652 653 is_dyn = elf_check_header(eh, ET_DYN) == 0; 654 /* 655 * XXX allow for executing shared objects. It seems silly 656 * but other ELF-based systems allow it as well. 657 */ 658 if (elf_check_header(eh, ET_EXEC) != 0 && !is_dyn) 659 return ENOEXEC; 660 661 if (eh->e_phnum > MAXPHNUM || eh->e_phnum == 0) 662 return ENOEXEC; 663 664 error = vn_marktext(epp->ep_vp); 665 if (error) 666 return error; 667 668 /* 669 * Allocate space to hold all the program headers, and read them 670 * from the file 671 */ 672 p = l->l_proc; 673 phsize = eh->e_phnum * sizeof(Elf_Phdr); 674 ph = kmem_alloc(phsize, KM_SLEEP); 675 676 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 677 0) 678 goto bad; 679 680 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 681 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 682 683 for (i = 0; i < eh->e_phnum; i++) { 684 pp = &ph[i]; 685 if (pp->p_type == PT_INTERP) { 686 if (pp->p_filesz >= MAXPATHLEN) { 687 error = ENOEXEC; 688 goto bad; 689 } 690 interp = PNBUF_GET(); 691 interp[0] = '\0'; 692 if ((error = exec_read_from(l, epp->ep_vp, 693 pp->p_offset, interp, pp->p_filesz)) != 0) 694 goto bad; 695 break; 696 } 697 } 698 699 /* 700 * On the same architecture, we may be emulating different systems. 701 * See which one will accept this executable. 702 * 703 * Probe functions would normally see if the interpreter (if any) 704 * exists. Emulation packages may possibly replace the interpreter in 705 * interp[] with a changed path (/emul/xxx/<path>). 706 */ 707 pos = ELFDEFNNAME(NO_ADDR); 708 if (epp->ep_esch->u.elf_probe_func) { 709 vaddr_t startp = (vaddr_t)pos; 710 711 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 712 &startp); 713 if (error) 714 goto bad; 715 pos = (Elf_Addr)startp; 716 } 717 718 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD) || defined(PAX_ASLR) 719 p->p_pax = epp->ep_pax_flags; 720 #endif /* PAX_MPROTECT || PAX_SEGVGUARD || PAX_ASLR */ 721 722 if (is_dyn) 723 elf_placedynexec(l, epp, eh, ph); 724 725 /* 726 * Load all the necessary sections 727 */ 728 for (i = nload = 0; i < eh->e_phnum; i++) { 729 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 730 u_long size = 0; 731 int prot = 0; 732 733 pp = &ph[i]; 734 735 switch (ph[i].p_type) { 736 case PT_LOAD: 737 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 738 &ph[i], &addr, &size, &prot, VMCMD_FIXED); 739 740 /* 741 * Consider this as text segment, if it is executable. 742 * If there is more than one text segment, pick the 743 * largest. 744 */ 745 if (ph[i].p_flags & PF_X) { 746 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 747 size > epp->ep_tsize) { 748 epp->ep_taddr = addr; 749 epp->ep_tsize = size; 750 } 751 end_text = addr + size; 752 } else { 753 epp->ep_daddr = addr; 754 epp->ep_dsize = size; 755 } 756 if (ph[i].p_offset == 0) { 757 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 758 } 759 break; 760 761 case PT_SHLIB: 762 /* SCO has these sections. */ 763 case PT_INTERP: 764 /* Already did this one. */ 765 case PT_DYNAMIC: 766 break; 767 case PT_NOTE: 768 break; 769 case PT_PHDR: 770 /* Note address of program headers (in text segment) */ 771 phdr = pp->p_vaddr; 772 break; 773 774 default: 775 /* 776 * Not fatal; we don't need to understand everything. 777 */ 778 break; 779 } 780 } 781 if (interp || (epp->ep_flags & EXEC_FORCEAUX) != 0) { 782 ap = malloc(sizeof(struct elf_args), M_TEMP, M_WAITOK); 783 ap->arg_interp = (vaddr_t)NULL; 784 } 785 786 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 787 epp->ep_daddr = round_page(end_text); 788 epp->ep_dsize = 0; 789 } 790 791 /* 792 * Check if we found a dynamically linked binary and arrange to load 793 * its interpreter 794 */ 795 if (interp) { 796 int j = epp->ep_vmcmds.evs_used; 797 u_long interp_offset; 798 799 if ((error = elf_load_file(l, epp, interp, 800 &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { 801 goto bad; 802 } 803 ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; 804 epp->ep_entry = ap->arg_interp + interp_offset; 805 PNBUF_PUT(interp); 806 } else 807 epp->ep_entry = eh->e_entry; 808 809 if (ap) { 810 ap->arg_phaddr = phdr ? phdr : computed_phdr; 811 ap->arg_phentsize = eh->e_phentsize; 812 ap->arg_phnum = eh->e_phnum; 813 ap->arg_entry = eh->e_entry; 814 epp->ep_emul_arg = ap; 815 } 816 817 #ifdef ELF_MAP_PAGE_ZERO 818 /* Dell SVR4 maps page zero, yeuch! */ 819 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 820 epp->ep_vp, 0, VM_PROT_READ); 821 #endif 822 kmem_free(ph, phsize); 823 return (*epp->ep_esch->es_setup_stack)(l, epp); 824 825 bad: 826 if (interp) 827 PNBUF_PUT(interp); 828 if (ap) 829 free(ap, M_TEMP); 830 kmem_free(ph, phsize); 831 kill_vmcmds(&epp->ep_vmcmds); 832 return error; 833 } 834 835 int 836 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 837 Elf_Ehdr *eh) 838 { 839 size_t i; 840 Elf_Shdr *sh; 841 Elf_Nhdr *np; 842 size_t shsize; 843 int error; 844 int isnetbsd = 0; 845 char *ndata; 846 847 epp->ep_pax_flags = 0; 848 if (eh->e_shnum > MAXSHNUM || eh->e_shnum == 0) 849 return ENOEXEC; 850 851 shsize = eh->e_shnum * sizeof(Elf_Shdr); 852 sh = kmem_alloc(shsize, KM_SLEEP); 853 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 854 if (error) 855 goto out; 856 857 np = kmem_alloc(MAXNOTESIZE, KM_SLEEP); 858 for (i = 0; i < eh->e_shnum; i++) { 859 Elf_Shdr *shp = &sh[i]; 860 861 if (shp->sh_type != SHT_NOTE || 862 shp->sh_size > MAXNOTESIZE || 863 shp->sh_size < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) 864 continue; 865 866 error = exec_read_from(l, epp->ep_vp, shp->sh_offset, np, 867 shp->sh_size); 868 if (error) 869 continue; 870 871 ndata = (char *)(np + 1); 872 switch (np->n_type) { 873 case ELF_NOTE_TYPE_NETBSD_TAG: 874 if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || 875 np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || 876 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 877 ELF_NOTE_NETBSD_NAMESZ)) 878 goto bad; 879 isnetbsd = 1; 880 break; 881 882 case ELF_NOTE_TYPE_PAX_TAG: 883 if (np->n_namesz != ELF_NOTE_PAX_NAMESZ || 884 np->n_descsz != ELF_NOTE_PAX_DESCSZ || 885 memcmp(ndata, ELF_NOTE_PAX_NAME, 886 ELF_NOTE_PAX_NAMESZ)) { 887 bad: 888 #ifdef DIAGNOSTIC 889 printf("%s: bad tag %d: " 890 "[%d %d, %d %d, %*.*s %*.*s]\n", 891 epp->ep_kname, 892 np->n_type, 893 np->n_namesz, ELF_NOTE_PAX_NAMESZ, 894 np->n_descsz, ELF_NOTE_PAX_DESCSZ, 895 ELF_NOTE_PAX_NAMESZ, 896 ELF_NOTE_PAX_NAMESZ, 897 ndata, 898 ELF_NOTE_PAX_NAMESZ, 899 ELF_NOTE_PAX_NAMESZ, 900 ELF_NOTE_PAX_NAME); 901 #endif 902 continue; 903 } 904 (void)memcpy(&epp->ep_pax_flags, 905 ndata + ELF_NOTE_PAX_NAMESZ, 906 sizeof(epp->ep_pax_flags)); 907 break; 908 909 default: 910 #ifdef DIAGNOSTIC 911 printf("%s: unknown note type %d\n", epp->ep_kname, 912 np->n_type); 913 #endif 914 break; 915 } 916 } 917 kmem_free(np, MAXNOTESIZE); 918 919 error = isnetbsd ? 0 : ENOEXEC; 920 out: 921 kmem_free(sh, shsize); 922 return error; 923 } 924 925 int 926 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 927 vaddr_t *pos) 928 { 929 int error; 930 931 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 932 return error; 933 #ifdef ELF_MD_PROBE_FUNC 934 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 935 return error; 936 #elif defined(ELF_INTERP_NON_RELOCATABLE) 937 *pos = ELF_LINK_ADDR; 938 #endif 939 return 0; 940 } 941
Indexes created Sun Sep 21 20:09:37 GMT 2025