1 /* $NetBSD: exec_elf.c,v 1.89 2017/02/18 01:29:09 chs Exp $ */ 2 3 /*- 4 * Copyright (c) 1994, 2000, 2005, 2015 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 and Maxime Villard. 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 1.89 2017/02/18 01:29:09 chs 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 80 #include <sys/cpu.h> 81 #include <machine/reg.h> 82 83 #include <compat/common/compat_util.h> 84 85 #include <sys/pax.h> 86 #include <uvm/uvm_param.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_interp ELFNAME(load_interp) 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_note ELFNAME2(netbsd,note) 97 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 98 #define coredump ELFNAMEEND(coredump) 99 #define elf_free_emul_arg ELFNAME(free_emul_arg) 100 101 static int 102 elf_load_interp(struct lwp *, struct exec_package *, char *, 103 struct exec_vmcmd_set *, u_long *, Elf_Addr *); 104 static void 105 elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, 106 Elf_Addr *, u_long *, int); 107 108 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 109 int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *, 110 const char *); 111 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 112 vaddr_t *); 113 114 static void elf_free_emul_arg(void *); 115 116 #ifdef DEBUG_ELF 117 #define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__) 118 #else 119 #define DPRINTF(a, ...) 120 #endif 121 122 /* round up and down to page boundaries. */ 123 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 124 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 125 126 static void 127 elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph) 128 { 129 Elf_Addr align, offset; 130 int i; 131 132 for (align = i = 0; i < eh->e_phnum; i++) 133 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 134 align = ph[i].p_align; 135 136 offset = (Elf_Addr)pax_aslr_exec_offset(epp, align); 137 if (offset < epp->ep_vm_minaddr) 138 offset = roundup(epp->ep_vm_minaddr, align); 139 KASSERT((offset & (align - 1)) == 0); 140 141 for (i = 0; i < eh->e_phnum; i++) 142 ph[i].p_vaddr += offset; 143 epp->ep_entryoffset = offset; 144 eh->e_entry += offset; 145 } 146 147 /* 148 * Copy arguments onto the stack in the normal way, but add some 149 * extra information in case of dynamic binding. 150 */ 151 int 152 elf_copyargs(struct lwp *l, struct exec_package *pack, 153 struct ps_strings *arginfo, char **stackp, void *argp) 154 { 155 size_t len, vlen; 156 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 157 struct elf_args *ap; 158 int error; 159 160 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 161 return error; 162 163 a = ai; 164 execname = NULL; 165 166 memset(ai, 0, sizeof(ai)); 167 168 /* 169 * Push extra arguments on the stack needed by dynamically 170 * linked binaries 171 */ 172 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 173 struct vattr *vap = pack->ep_vap; 174 175 a->a_type = AT_PHDR; 176 a->a_v = ap->arg_phaddr; 177 a++; 178 179 a->a_type = AT_PHENT; 180 a->a_v = ap->arg_phentsize; 181 a++; 182 183 a->a_type = AT_PHNUM; 184 a->a_v = ap->arg_phnum; 185 a++; 186 187 a->a_type = AT_PAGESZ; 188 a->a_v = PAGE_SIZE; 189 a++; 190 191 a->a_type = AT_BASE; 192 a->a_v = ap->arg_interp; 193 a++; 194 195 a->a_type = AT_FLAGS; 196 a->a_v = 0; 197 a++; 198 199 a->a_type = AT_ENTRY; 200 a->a_v = ap->arg_entry; 201 a++; 202 203 a->a_type = AT_EUID; 204 if (vap->va_mode & S_ISUID) 205 a->a_v = vap->va_uid; 206 else 207 a->a_v = kauth_cred_geteuid(l->l_cred); 208 a++; 209 210 a->a_type = AT_RUID; 211 a->a_v = kauth_cred_getuid(l->l_cred); 212 a++; 213 214 a->a_type = AT_EGID; 215 if (vap->va_mode & S_ISGID) 216 a->a_v = vap->va_gid; 217 else 218 a->a_v = kauth_cred_getegid(l->l_cred); 219 a++; 220 221 a->a_type = AT_RGID; 222 a->a_v = kauth_cred_getgid(l->l_cred); 223 a++; 224 225 a->a_type = AT_STACKBASE; 226 a->a_v = l->l_proc->p_stackbase; 227 a++; 228 229 if (pack->ep_path) { 230 execname = a; 231 a->a_type = AT_SUN_EXECNAME; 232 a++; 233 } 234 235 exec_free_emul_arg(pack); 236 } 237 238 a->a_type = AT_NULL; 239 a->a_v = 0; 240 a++; 241 242 vlen = (a - ai) * sizeof(ai[0]); 243 244 KASSERT(vlen <= sizeof(ai)); 245 246 if (execname) { 247 char *path = pack->ep_path; 248 execname->a_v = (uintptr_t)(*stackp + vlen); 249 len = strlen(path) + 1; 250 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 251 return error; 252 len = ALIGN(len); 253 } else 254 len = 0; 255 256 if ((error = copyout(ai, *stackp, vlen)) != 0) 257 return error; 258 *stackp += vlen + len; 259 260 return 0; 261 } 262 263 /* 264 * elf_check_header(): 265 * 266 * Check header for validity; return 0 if ok, ENOEXEC if error 267 */ 268 int 269 elf_check_header(Elf_Ehdr *eh) 270 { 271 272 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 273 eh->e_ident[EI_CLASS] != ELFCLASS) { 274 DPRINTF("bad magic %#x%x%x", eh->e_ident[0], eh->e_ident[1], 275 eh->e_ident[2]); 276 return ENOEXEC; 277 } 278 279 switch (eh->e_machine) { 280 281 ELFDEFNNAME(MACHDEP_ID_CASES) 282 283 default: 284 DPRINTF("bad machine %#x", eh->e_machine); 285 return ENOEXEC; 286 } 287 288 if (ELF_EHDR_FLAGS_OK(eh) == 0) { 289 DPRINTF("bad flags %#x", eh->e_flags); 290 return ENOEXEC; 291 } 292 293 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { 294 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum); 295 return ENOEXEC; 296 } 297 298 return 0; 299 } 300 301 /* 302 * elf_load_psection(): 303 * 304 * Load a psection at the appropriate address 305 */ 306 static void 307 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 308 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) 309 { 310 u_long msize, psize, rm, rf; 311 long diff, offset; 312 int vmprot = 0; 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 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 335 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 336 vmprot |= (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, vmprot, 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, vmprot, 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, vmprot, flags & VMCMD_RELATIVE); 382 *size = msize; 383 } 384 } 385 386 /* 387 * elf_load_interp(): 388 * 389 * Load an interpreter pointed to by path. 390 */ 391 static int 392 elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, 393 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) 394 { 395 int error, i; 396 struct vnode *vp; 397 struct vattr attr; 398 Elf_Ehdr eh; 399 Elf_Phdr *ph = NULL; 400 const Elf_Phdr *base_ph; 401 const Elf_Phdr *last_ph; 402 u_long phsize; 403 Elf_Addr addr = *last; 404 struct proc *p; 405 bool use_topdown; 406 407 p = l->l_proc; 408 409 KASSERT(p->p_vmspace); 410 KASSERT(p->p_vmspace != proc0.p_vmspace); 411 412 #ifdef __USE_TOPDOWN_VM 413 use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM; 414 #else 415 use_topdown = false; 416 #endif 417 418 /* 419 * 1. open file 420 * 2. read filehdr 421 * 3. map text, data, and bss out of it using VM_* 422 */ 423 vp = epp->ep_interp; 424 if (vp == NULL) { 425 error = emul_find_interp(l, epp, path); 426 if (error != 0) 427 return error; 428 vp = epp->ep_interp; 429 } 430 /* We'll tidy this ourselves - otherwise we have locking issues */ 431 epp->ep_interp = NULL; 432 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 433 434 /* 435 * Similarly, if it's not marked as executable, or it's not a regular 436 * file, we don't allow it to be used. 437 */ 438 if (vp->v_type != VREG) { 439 error = EACCES; 440 goto badunlock; 441 } 442 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 443 goto badunlock; 444 445 /* get attributes */ 446 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 447 goto badunlock; 448 449 /* 450 * Check mount point. Though we're not trying to exec this binary, 451 * we will be executing code from it, so if the mount point 452 * disallows execution or set-id-ness, we punt or kill the set-id. 453 */ 454 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 455 error = EACCES; 456 goto badunlock; 457 } 458 if (vp->v_mount->mnt_flag & MNT_NOSUID) 459 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 460 461 error = vn_marktext(vp); 462 if (error) 463 goto badunlock; 464 465 VOP_UNLOCK(vp); 466 467 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 468 goto bad; 469 470 if ((error = elf_check_header(&eh)) != 0) 471 goto bad; 472 if (eh.e_type != ET_DYN || eh.e_phnum == 0) { 473 DPRINTF("bad interpreter type %#x", eh.e_type); 474 error = ENOEXEC; 475 goto bad; 476 } 477 478 phsize = eh.e_phnum * sizeof(Elf_Phdr); 479 ph = kmem_alloc(phsize, KM_SLEEP); 480 481 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 482 goto bad; 483 484 #ifdef ELF_INTERP_NON_RELOCATABLE 485 /* 486 * Evil hack: Only MIPS should be non-relocatable, and the 487 * psections should have a high address (typically 0x5ffe0000). 488 * If it's now relocatable, it should be linked at 0 and the 489 * psections should have zeros in the upper part of the address. 490 * Otherwise, force the load at the linked address. 491 */ 492 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 493 *last = ELFDEFNNAME(NO_ADDR); 494 #endif 495 496 /* 497 * If no position to load the interpreter was set by a probe 498 * function, pick the same address that a non-fixed mmap(0, ..) 499 * would (i.e. something safely out of the way). 500 */ 501 if (*last == ELFDEFNNAME(NO_ADDR)) { 502 u_long limit = 0; 503 /* 504 * Find the start and ending addresses of the psections to 505 * be loaded. This will give us the size. 506 */ 507 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { 508 if (ph[i].p_type == PT_LOAD) { 509 u_long psize = ph[i].p_vaddr + ph[i].p_memsz; 510 if (base_ph == NULL) 511 base_ph = &ph[i]; 512 if (psize > limit) 513 limit = psize; 514 } 515 } 516 517 if (base_ph == NULL) { 518 DPRINTF("no interpreter loadable sections"); 519 error = ENOEXEC; 520 goto bad; 521 } 522 523 /* 524 * Now compute the size and load address. 525 */ 526 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 527 epp->ep_daddr, 528 round_page(limit) - trunc_page(base_ph->p_vaddr), 529 use_topdown); 530 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, 531 use_topdown); 532 } else { 533 addr = *last; /* may be ELF_LINK_ADDR */ 534 } 535 536 /* 537 * Load all the necessary sections 538 */ 539 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { 540 switch (ph[i].p_type) { 541 case PT_LOAD: { 542 u_long size; 543 int flags; 544 545 if (base_ph == NULL) { 546 /* 547 * First encountered psection is always the 548 * base psection. Make sure it's aligned 549 * properly (align down for topdown and align 550 * upwards for not topdown). 551 */ 552 base_ph = &ph[i]; 553 flags = VMCMD_BASE; 554 if (addr == ELF_LINK_ADDR) 555 addr = ph[i].p_vaddr; 556 if (use_topdown) 557 addr = ELF_TRUNC(addr, ph[i].p_align); 558 else 559 addr = ELF_ROUND(addr, ph[i].p_align); 560 } else { 561 u_long limit = round_page(last_ph->p_vaddr 562 + last_ph->p_memsz); 563 u_long base = trunc_page(ph[i].p_vaddr); 564 565 /* 566 * If there is a gap in between the psections, 567 * map it as inaccessible so nothing else 568 * mmap'ed will be placed there. 569 */ 570 if (limit != base) { 571 NEW_VMCMD2(vcset, vmcmd_map_zero, 572 base - limit, 573 limit - base_ph->p_vaddr, NULLVP, 574 0, VM_PROT_NONE, VMCMD_RELATIVE); 575 } 576 577 addr = ph[i].p_vaddr - base_ph->p_vaddr; 578 flags = VMCMD_RELATIVE; 579 } 580 last_ph = &ph[i]; 581 elf_load_psection(vcset, vp, &ph[i], &addr, 582 &size, flags); 583 /* 584 * If entry is within this psection then this 585 * must contain the .text section. *entryoff is 586 * relative to the base psection. 587 */ 588 if (eh.e_entry >= ph[i].p_vaddr && 589 eh.e_entry < (ph[i].p_vaddr + size)) { 590 *entryoff = eh.e_entry - base_ph->p_vaddr; 591 } 592 addr += size; 593 break; 594 } 595 596 default: 597 break; 598 } 599 } 600 601 kmem_free(ph, phsize); 602 /* 603 * This value is ignored if TOPDOWN. 604 */ 605 *last = addr; 606 vrele(vp); 607 return 0; 608 609 badunlock: 610 VOP_UNLOCK(vp); 611 612 bad: 613 if (ph != NULL) 614 kmem_free(ph, phsize); 615 vrele(vp); 616 return error; 617 } 618 619 /* 620 * exec_elf_makecmds(): Prepare an Elf binary's exec package 621 * 622 * First, set of the various offsets/lengths in the exec package. 623 * 624 * Then, mark the text image busy (so it can be demand paged) or error 625 * out if this is not possible. Finally, set up vmcmds for the 626 * text, data, bss, and stack segments. 627 */ 628 int 629 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 630 { 631 Elf_Ehdr *eh = epp->ep_hdr; 632 Elf_Phdr *ph, *pp; 633 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 634 int error, i; 635 char *interp = NULL; 636 u_long phsize; 637 struct elf_args *ap; 638 bool is_dyn = false; 639 640 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { 641 DPRINTF("small header %#x", epp->ep_hdrvalid); 642 return ENOEXEC; 643 } 644 if ((error = elf_check_header(eh)) != 0) 645 return error; 646 647 if (eh->e_type == ET_DYN) 648 /* PIE, and some libs have an entry point */ 649 is_dyn = true; 650 else if (eh->e_type != ET_EXEC) { 651 DPRINTF("bad type %#x", eh->e_type); 652 return ENOEXEC; 653 } 654 655 if (eh->e_phnum == 0) { 656 DPRINTF("no program headers"); 657 return ENOEXEC; 658 } 659 660 error = vn_marktext(epp->ep_vp); 661 if (error) 662 return error; 663 664 /* 665 * Allocate space to hold all the program headers, and read them 666 * from the file 667 */ 668 phsize = eh->e_phnum * sizeof(Elf_Phdr); 669 ph = kmem_alloc(phsize, KM_SLEEP); 670 671 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 672 0) 673 goto bad; 674 675 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 676 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 677 678 for (i = 0; i < eh->e_phnum; i++) { 679 pp = &ph[i]; 680 if (pp->p_type == PT_INTERP) { 681 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { 682 DPRINTF("bad interpreter namelen %#jx", 683 (uintmax_t)pp->p_filesz); 684 error = ENOEXEC; 685 goto bad; 686 } 687 interp = PNBUF_GET(); 688 if ((error = exec_read_from(l, epp->ep_vp, 689 pp->p_offset, interp, pp->p_filesz)) != 0) 690 goto bad; 691 /* Ensure interp is NUL-terminated and of the expected length */ 692 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { 693 DPRINTF("bad interpreter name"); 694 error = ENOEXEC; 695 goto bad; 696 } 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 (is_dyn) 721 elf_placedynexec(epp, eh, ph); 722 723 /* 724 * Load all the necessary sections 725 */ 726 for (i = 0; i < eh->e_phnum; i++) { 727 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 728 u_long size = 0; 729 730 switch (ph[i].p_type) { 731 case PT_LOAD: 732 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 733 &ph[i], &addr, &size, VMCMD_FIXED); 734 735 /* 736 * Consider this as text segment, if it is executable. 737 * If there is more than one text segment, pick the 738 * largest. 739 */ 740 if (ph[i].p_flags & PF_X) { 741 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 742 size > epp->ep_tsize) { 743 epp->ep_taddr = addr; 744 epp->ep_tsize = size; 745 } 746 end_text = addr + size; 747 } else { 748 epp->ep_daddr = addr; 749 epp->ep_dsize = size; 750 } 751 if (ph[i].p_offset == 0) { 752 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 753 } 754 break; 755 756 case PT_SHLIB: 757 /* SCO has these sections. */ 758 case PT_INTERP: 759 /* Already did this one. */ 760 case PT_DYNAMIC: 761 case PT_NOTE: 762 break; 763 case PT_PHDR: 764 /* Note address of program headers (in text segment) */ 765 phdr = ph[i].p_vaddr; 766 break; 767 768 default: 769 /* 770 * Not fatal; we don't need to understand everything. 771 */ 772 break; 773 } 774 } 775 776 if (epp->ep_vmcmds.evs_used == 0) { 777 /* No VMCMD; there was no PT_LOAD section, or those 778 * sections were empty */ 779 DPRINTF("no vmcommands"); 780 error = ENOEXEC; 781 goto bad; 782 } 783 784 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 785 epp->ep_daddr = round_page(end_text); 786 epp->ep_dsize = 0; 787 } 788 789 /* 790 * Check if we found a dynamically linked binary and arrange to load 791 * its interpreter 792 */ 793 if (interp) { 794 u_int nused = epp->ep_vmcmds.evs_used; 795 u_long interp_offset = 0; 796 797 if ((error = elf_load_interp(l, epp, interp, 798 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { 799 goto bad; 800 } 801 if (epp->ep_vmcmds.evs_used == nused) { 802 /* elf_load_interp() has not set up any new VMCMD */ 803 DPRINTF("no vmcommands for interpreter"); 804 error = ENOEXEC; 805 goto bad; 806 } 807 808 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 809 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; 810 epp->ep_entryoffset = interp_offset; 811 epp->ep_entry = ap->arg_interp + interp_offset; 812 PNBUF_PUT(interp); 813 interp = NULL; 814 } else { 815 epp->ep_entry = eh->e_entry; 816 if (epp->ep_flags & EXEC_FORCEAUX) { 817 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 818 ap->arg_interp = (vaddr_t)NULL; 819 } else 820 ap = NULL; 821 } 822 823 if (ap) { 824 ap->arg_phaddr = phdr ? phdr : computed_phdr; 825 ap->arg_phentsize = eh->e_phentsize; 826 ap->arg_phnum = eh->e_phnum; 827 ap->arg_entry = eh->e_entry; 828 epp->ep_emul_arg = ap; 829 epp->ep_emul_arg_free = elf_free_emul_arg; 830 } 831 832 #ifdef ELF_MAP_PAGE_ZERO 833 /* Dell SVR4 maps page zero, yeuch! */ 834 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 835 epp->ep_vp, 0, VM_PROT_READ); 836 #endif 837 838 error = (*epp->ep_esch->es_setup_stack)(l, epp); 839 if (error) 840 goto bad; 841 842 kmem_free(ph, phsize); 843 return 0; 844 845 bad: 846 if (interp) 847 PNBUF_PUT(interp); 848 exec_free_emul_arg(epp); 849 kmem_free(ph, phsize); 850 kill_vmcmds(&epp->ep_vmcmds); 851 return error; 852 } 853 854 int 855 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 856 Elf_Ehdr *eh) 857 { 858 size_t i; 859 Elf_Phdr *ph; 860 size_t phsize; 861 char *nbuf; 862 int error; 863 int isnetbsd = 0; 864 865 epp->ep_pax_flags = 0; 866 867 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) { 868 DPRINTF("no signature %#x", eh->e_phnum); 869 return ENOEXEC; 870 } 871 872 phsize = eh->e_phnum * sizeof(Elf_Phdr); 873 ph = kmem_alloc(phsize, KM_SLEEP); 874 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 875 if (error) 876 goto out; 877 878 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); 879 for (i = 0; i < eh->e_phnum; i++) { 880 const char *nptr; 881 size_t nlen; 882 883 if (ph[i].p_type != PT_NOTE || 884 ph[i].p_filesz > ELF_MAXNOTESIZE) 885 continue; 886 887 nlen = ph[i].p_filesz; 888 error = exec_read_from(l, epp->ep_vp, ph[i].p_offset, 889 nbuf, nlen); 890 if (error) 891 continue; 892 893 nptr = nbuf; 894 while (nlen > 0) { 895 const Elf_Nhdr *np; 896 const char *ndata, *ndesc; 897 898 /* note header */ 899 np = (const Elf_Nhdr *)nptr; 900 if (nlen < sizeof(*np)) { 901 break; 902 } 903 nptr += sizeof(*np); 904 nlen -= sizeof(*np); 905 906 /* note name */ 907 ndata = nptr; 908 if (nlen < roundup(np->n_namesz, 4)) { 909 break; 910 } 911 nptr += roundup(np->n_namesz, 4); 912 nlen -= roundup(np->n_namesz, 4); 913 914 /* note description */ 915 ndesc = nptr; 916 if (nlen < roundup(np->n_descsz, 4)) { 917 break; 918 } 919 nptr += roundup(np->n_descsz, 4); 920 nlen -= roundup(np->n_descsz, 4); 921 922 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc); 923 } 924 } 925 kmem_free(nbuf, ELF_MAXNOTESIZE); 926 927 error = isnetbsd ? 0 : ENOEXEC; 928 #ifdef DEBUG_ELF 929 if (error) 930 DPRINTF("not netbsd"); 931 #endif 932 out: 933 kmem_free(ph, phsize); 934 return error; 935 } 936 937 int 938 netbsd_elf_note(struct exec_package *epp, 939 const Elf_Nhdr *np, const char *ndata, const char *ndesc) 940 { 941 int isnetbsd = 0; 942 943 #ifdef DIAGNOSTIC 944 const char *badnote; 945 #define BADNOTE(n) badnote = (n) 946 #else 947 #define BADNOTE(n) 948 #endif 949 950 switch (np->n_type) { 951 case ELF_NOTE_TYPE_NETBSD_TAG: 952 /* It is us */ 953 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && 954 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && 955 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 956 ELF_NOTE_NETBSD_NAMESZ) == 0) { 957 memcpy(&epp->ep_osversion, ndesc, 958 ELF_NOTE_NETBSD_DESCSZ); 959 isnetbsd = 1; 960 break; 961 } 962 963 /* 964 * Ignore SuSE tags; SuSE's n_type is the same the 965 * NetBSD one. 966 */ 967 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && 968 memcmp(ndata, ELF_NOTE_SUSE_NAME, 969 ELF_NOTE_SUSE_NAMESZ) == 0) 970 break; 971 /* 972 * Ignore old GCC 973 */ 974 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && 975 memcmp(ndata, ELF_NOTE_OGCC_NAME, 976 ELF_NOTE_OGCC_NAMESZ) == 0) 977 break; 978 BADNOTE("NetBSD tag"); 979 goto bad; 980 981 case ELF_NOTE_TYPE_PAX_TAG: 982 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && 983 np->n_descsz == ELF_NOTE_PAX_DESCSZ && 984 memcmp(ndata, ELF_NOTE_PAX_NAME, 985 ELF_NOTE_PAX_NAMESZ) == 0) { 986 uint32_t flags; 987 memcpy(&flags, ndesc, sizeof(flags)); 988 /* Convert the flags and insert them into 989 * the exec package. */ 990 pax_setup_elf_flags(epp, flags); 991 break; 992 } 993 BADNOTE("PaX tag"); 994 goto bad; 995 996 case ELF_NOTE_TYPE_MARCH_TAG: 997 /* Copy the machine arch into the package. */ 998 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ 999 && memcmp(ndata, ELF_NOTE_MARCH_NAME, 1000 ELF_NOTE_MARCH_NAMESZ) == 0) { 1001 /* Do not truncate the buffer */ 1002 if (np->n_descsz > sizeof(epp->ep_machine_arch)) { 1003 BADNOTE("description size limit"); 1004 goto bad; 1005 } 1006 /* 1007 * Ensure ndesc is NUL-terminated and of the 1008 * expected length. 1009 */ 1010 if (strnlen(ndesc, np->n_descsz) + 1 != 1011 np->n_descsz) { 1012 BADNOTE("description size"); 1013 goto bad; 1014 } 1015 strlcpy(epp->ep_machine_arch, ndesc, 1016 sizeof(epp->ep_machine_arch)); 1017 break; 1018 } 1019 BADNOTE("march tag"); 1020 goto bad; 1021 1022 case ELF_NOTE_TYPE_MCMODEL_TAG: 1023 /* arch specific check for code model */ 1024 #ifdef ELF_MD_MCMODEL_CHECK 1025 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ 1026 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, 1027 ELF_NOTE_MCMODEL_NAMESZ) == 0) { 1028 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); 1029 break; 1030 } 1031 BADNOTE("mcmodel tag"); 1032 goto bad; 1033 #endif 1034 break; 1035 1036 case ELF_NOTE_TYPE_SUSE_VERSION_TAG: 1037 break; 1038 1039 case ELF_NOTE_TYPE_GO_BUILDID_TAG: 1040 break; 1041 1042 default: 1043 BADNOTE("unknown tag"); 1044 bad: 1045 #ifdef DIAGNOSTIC 1046 /* Ignore GNU tags */ 1047 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 1048 memcmp(ndata, ELF_NOTE_GNU_NAME, 1049 ELF_NOTE_GNU_NAMESZ) == 0) 1050 break; 1051 1052 int ns = (int)np->n_namesz; 1053 printf("%s: Unknown elf note type %d (%s): " 1054 "[namesz=%d, descsz=%d name=%-*.*s]\n", 1055 epp->ep_kname, np->n_type, badnote, np->n_namesz, 1056 np->n_descsz, ns, ns, ndata); 1057 #endif 1058 break; 1059 } 1060 1061 return isnetbsd; 1062 } 1063 1064 int 1065 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 1066 vaddr_t *pos) 1067 { 1068 int error; 1069 1070 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 1071 return error; 1072 #ifdef ELF_MD_PROBE_FUNC 1073 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 1074 return error; 1075 #elif defined(ELF_INTERP_NON_RELOCATABLE) 1076 *pos = ELF_LINK_ADDR; 1077 #endif 1078 epp->ep_flags |= EXEC_FORCEAUX; 1079 return 0; 1080 } 1081 1082 void 1083 elf_free_emul_arg(void *arg) 1084 { 1085 struct elf_args *ap = arg; 1086 KASSERT(ap != NULL); 1087 kmem_free(ap, sizeof(*ap)); 1088 } 1089