1 /* $NetBSD: exec_elf.c,v 1.90 2017/04/21 13:17:42 kamil 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 1.90 2017/04/21 13:17:42 kamil 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 e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, " 275 "e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0], 276 eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2], 277 eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]); 278 return ENOEXEC; 279 } 280 281 switch (eh->e_machine) { 282 283 ELFDEFNNAME(MACHDEP_ID_CASES) 284 285 default: 286 DPRINTF("bad machine %#x", eh->e_machine); 287 return ENOEXEC; 288 } 289 290 if (ELF_EHDR_FLAGS_OK(eh) == 0) { 291 DPRINTF("bad flags %#x", eh->e_flags); 292 return ENOEXEC; 293 } 294 295 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { 296 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum); 297 return ENOEXEC; 298 } 299 300 return 0; 301 } 302 303 /* 304 * elf_load_psection(): 305 * 306 * Load a psection at the appropriate address 307 */ 308 static void 309 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 310 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) 311 { 312 u_long msize, psize, rm, rf; 313 long diff, offset; 314 int vmprot = 0; 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 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 337 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 338 vmprot |= (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, vmprot, 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, vmprot, 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, vmprot, flags & VMCMD_RELATIVE); 384 *size = msize; 385 } 386 } 387 388 /* 389 * elf_load_interp(): 390 * 391 * Load an interpreter pointed to by path. 392 */ 393 static int 394 elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, 395 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) 396 { 397 int error, i; 398 struct vnode *vp; 399 struct vattr attr; 400 Elf_Ehdr eh; 401 Elf_Phdr *ph = NULL; 402 const Elf_Phdr *base_ph; 403 const Elf_Phdr *last_ph; 404 u_long phsize; 405 Elf_Addr addr = *last; 406 struct proc *p; 407 bool use_topdown; 408 409 p = l->l_proc; 410 411 KASSERT(p->p_vmspace); 412 KASSERT(p->p_vmspace != proc0.p_vmspace); 413 414 #ifdef __USE_TOPDOWN_VM 415 use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM; 416 #else 417 use_topdown = false; 418 #endif 419 420 /* 421 * 1. open file 422 * 2. read filehdr 423 * 3. map text, data, and bss out of it using VM_* 424 */ 425 vp = epp->ep_interp; 426 if (vp == NULL) { 427 error = emul_find_interp(l, epp, path); 428 if (error != 0) 429 return error; 430 vp = epp->ep_interp; 431 } 432 /* We'll tidy this ourselves - otherwise we have locking issues */ 433 epp->ep_interp = NULL; 434 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 435 436 /* 437 * Similarly, if it's not marked as executable, or it's not a regular 438 * file, we don't allow it to be used. 439 */ 440 if (vp->v_type != VREG) { 441 error = EACCES; 442 goto badunlock; 443 } 444 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 445 goto badunlock; 446 447 /* get attributes */ 448 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 449 goto badunlock; 450 451 /* 452 * Check mount point. Though we're not trying to exec this binary, 453 * we will be executing code from it, so if the mount point 454 * disallows execution or set-id-ness, we punt or kill the set-id. 455 */ 456 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 457 error = EACCES; 458 goto badunlock; 459 } 460 if (vp->v_mount->mnt_flag & MNT_NOSUID) 461 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 462 463 error = vn_marktext(vp); 464 if (error) 465 goto badunlock; 466 467 VOP_UNLOCK(vp); 468 469 if ((error = exec_read_from(l, vp, 0, &eh, sizeof(eh))) != 0) 470 goto bad; 471 472 if ((error = elf_check_header(&eh)) != 0) 473 goto bad; 474 if (eh.e_type != ET_DYN || eh.e_phnum == 0) { 475 DPRINTF("bad interpreter type %#x", eh.e_type); 476 error = ENOEXEC; 477 goto bad; 478 } 479 480 phsize = eh.e_phnum * sizeof(Elf_Phdr); 481 ph = kmem_alloc(phsize, KM_SLEEP); 482 483 if ((error = exec_read_from(l, vp, eh.e_phoff, ph, phsize)) != 0) 484 goto bad; 485 486 #ifdef ELF_INTERP_NON_RELOCATABLE 487 /* 488 * Evil hack: Only MIPS should be non-relocatable, and the 489 * psections should have a high address (typically 0x5ffe0000). 490 * If it's now relocatable, it should be linked at 0 and the 491 * psections should have zeros in the upper part of the address. 492 * Otherwise, force the load at the linked address. 493 */ 494 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 495 *last = ELFDEFNNAME(NO_ADDR); 496 #endif 497 498 /* 499 * If no position to load the interpreter was set by a probe 500 * function, pick the same address that a non-fixed mmap(0, ..) 501 * would (i.e. something safely out of the way). 502 */ 503 if (*last == ELFDEFNNAME(NO_ADDR)) { 504 u_long limit = 0; 505 /* 506 * Find the start and ending addresses of the psections to 507 * be loaded. This will give us the size. 508 */ 509 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { 510 if (ph[i].p_type == PT_LOAD) { 511 u_long psize = ph[i].p_vaddr + ph[i].p_memsz; 512 if (base_ph == NULL) 513 base_ph = &ph[i]; 514 if (psize > limit) 515 limit = psize; 516 } 517 } 518 519 if (base_ph == NULL) { 520 DPRINTF("no interpreter loadable sections"); 521 error = ENOEXEC; 522 goto bad; 523 } 524 525 /* 526 * Now compute the size and load address. 527 */ 528 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 529 epp->ep_daddr, 530 round_page(limit) - trunc_page(base_ph->p_vaddr), 531 use_topdown); 532 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, 533 use_topdown); 534 } else { 535 addr = *last; /* may be ELF_LINK_ADDR */ 536 } 537 538 /* 539 * Load all the necessary sections 540 */ 541 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { 542 switch (ph[i].p_type) { 543 case PT_LOAD: { 544 u_long size; 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 = &ph[i]; 555 flags = VMCMD_BASE; 556 if (addr == ELF_LINK_ADDR) 557 addr = ph[i].p_vaddr; 558 if (use_topdown) 559 addr = ELF_TRUNC(addr, ph[i].p_align); 560 else 561 addr = ELF_ROUND(addr, ph[i].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(ph[i].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 = ph[i].p_vaddr - base_ph->p_vaddr; 580 flags = VMCMD_RELATIVE; 581 } 582 last_ph = &ph[i]; 583 elf_load_psection(vcset, vp, &ph[i], &addr, 584 &size, 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 >= ph[i].p_vaddr && 591 eh.e_entry < (ph[i].p_vaddr + size)) { 592 *entryoff = eh.e_entry - base_ph->p_vaddr; 593 } 594 addr += size; 595 break; 596 } 597 598 default: 599 break; 600 } 601 } 602 603 kmem_free(ph, phsize); 604 /* 605 * This value is ignored if TOPDOWN. 606 */ 607 *last = addr; 608 vrele(vp); 609 return 0; 610 611 badunlock: 612 VOP_UNLOCK(vp); 613 614 bad: 615 if (ph != NULL) 616 kmem_free(ph, phsize); 617 vrele(vp); 618 return error; 619 } 620 621 /* 622 * exec_elf_makecmds(): Prepare an Elf binary's exec package 623 * 624 * First, set of the various offsets/lengths in the exec package. 625 * 626 * Then, mark the text image busy (so it can be demand paged) or error 627 * out if this is not possible. Finally, set up vmcmds for the 628 * text, data, bss, and stack segments. 629 */ 630 int 631 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 632 { 633 Elf_Ehdr *eh = epp->ep_hdr; 634 Elf_Phdr *ph, *pp; 635 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 636 int error, i; 637 char *interp = NULL; 638 u_long phsize; 639 struct elf_args *ap; 640 bool is_dyn = false; 641 642 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { 643 DPRINTF("small header %#x", epp->ep_hdrvalid); 644 return ENOEXEC; 645 } 646 if ((error = elf_check_header(eh)) != 0) 647 return error; 648 649 if (eh->e_type == ET_DYN) 650 /* PIE, and some libs have an entry point */ 651 is_dyn = true; 652 else if (eh->e_type != ET_EXEC) { 653 DPRINTF("bad type %#x", eh->e_type); 654 return ENOEXEC; 655 } 656 657 if (eh->e_phnum == 0) { 658 DPRINTF("no program headers"); 659 return ENOEXEC; 660 } 661 662 error = vn_marktext(epp->ep_vp); 663 if (error) 664 return error; 665 666 /* 667 * Allocate space to hold all the program headers, and read them 668 * from the file 669 */ 670 phsize = eh->e_phnum * sizeof(Elf_Phdr); 671 ph = kmem_alloc(phsize, KM_SLEEP); 672 673 if ((error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize)) != 674 0) 675 goto bad; 676 677 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 678 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 679 680 for (i = 0; i < eh->e_phnum; i++) { 681 pp = &ph[i]; 682 if (pp->p_type == PT_INTERP) { 683 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { 684 DPRINTF("bad interpreter namelen %#jx", 685 (uintmax_t)pp->p_filesz); 686 error = ENOEXEC; 687 goto bad; 688 } 689 interp = PNBUF_GET(); 690 if ((error = exec_read_from(l, epp->ep_vp, 691 pp->p_offset, interp, pp->p_filesz)) != 0) 692 goto bad; 693 /* Ensure interp is NUL-terminated and of the expected length */ 694 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { 695 DPRINTF("bad interpreter name"); 696 error = ENOEXEC; 697 goto bad; 698 } 699 break; 700 } 701 } 702 703 /* 704 * On the same architecture, we may be emulating different systems. 705 * See which one will accept this executable. 706 * 707 * Probe functions would normally see if the interpreter (if any) 708 * exists. Emulation packages may possibly replace the interpreter in 709 * interp with a changed path (/emul/xxx/<path>). 710 */ 711 pos = ELFDEFNNAME(NO_ADDR); 712 if (epp->ep_esch->u.elf_probe_func) { 713 vaddr_t startp = (vaddr_t)pos; 714 715 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 716 &startp); 717 if (error) 718 goto bad; 719 pos = (Elf_Addr)startp; 720 } 721 722 if (is_dyn) 723 elf_placedynexec(epp, eh, ph); 724 725 /* 726 * Load all the necessary sections 727 */ 728 for (i = 0; i < eh->e_phnum; i++) { 729 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 730 u_long size = 0; 731 732 switch (ph[i].p_type) { 733 case PT_LOAD: 734 elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, 735 &ph[i], &addr, &size, VMCMD_FIXED); 736 737 /* 738 * Consider this as text segment, if it is executable. 739 * If there is more than one text segment, pick the 740 * largest. 741 */ 742 if (ph[i].p_flags & PF_X) { 743 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 744 size > epp->ep_tsize) { 745 epp->ep_taddr = addr; 746 epp->ep_tsize = size; 747 } 748 end_text = addr + size; 749 } else { 750 epp->ep_daddr = addr; 751 epp->ep_dsize = size; 752 } 753 if (ph[i].p_offset == 0) { 754 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 755 } 756 break; 757 758 case PT_SHLIB: 759 /* SCO has these sections. */ 760 case PT_INTERP: 761 /* Already did this one. */ 762 case PT_DYNAMIC: 763 case PT_NOTE: 764 break; 765 case PT_PHDR: 766 /* Note address of program headers (in text segment) */ 767 phdr = ph[i].p_vaddr; 768 break; 769 770 default: 771 /* 772 * Not fatal; we don't need to understand everything. 773 */ 774 break; 775 } 776 } 777 778 if (epp->ep_vmcmds.evs_used == 0) { 779 /* No VMCMD; there was no PT_LOAD section, or those 780 * sections were empty */ 781 DPRINTF("no vmcommands"); 782 error = ENOEXEC; 783 goto bad; 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 u_int nused = epp->ep_vmcmds.evs_used; 797 u_long interp_offset = 0; 798 799 if ((error = elf_load_interp(l, epp, interp, 800 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { 801 goto bad; 802 } 803 if (epp->ep_vmcmds.evs_used == nused) { 804 /* elf_load_interp() has not set up any new VMCMD */ 805 DPRINTF("no vmcommands for interpreter"); 806 error = ENOEXEC; 807 goto bad; 808 } 809 810 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 811 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; 812 epp->ep_entryoffset = interp_offset; 813 epp->ep_entry = ap->arg_interp + interp_offset; 814 PNBUF_PUT(interp); 815 interp = NULL; 816 } else { 817 epp->ep_entry = eh->e_entry; 818 if (epp->ep_flags & EXEC_FORCEAUX) { 819 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 820 ap->arg_interp = (vaddr_t)NULL; 821 } else 822 ap = NULL; 823 } 824 825 if (ap) { 826 ap->arg_phaddr = phdr ? phdr : computed_phdr; 827 ap->arg_phentsize = eh->e_phentsize; 828 ap->arg_phnum = eh->e_phnum; 829 ap->arg_entry = eh->e_entry; 830 epp->ep_emul_arg = ap; 831 epp->ep_emul_arg_free = elf_free_emul_arg; 832 } 833 834 #ifdef ELF_MAP_PAGE_ZERO 835 /* Dell SVR4 maps page zero, yeuch! */ 836 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 837 epp->ep_vp, 0, VM_PROT_READ); 838 #endif 839 840 error = (*epp->ep_esch->es_setup_stack)(l, epp); 841 if (error) 842 goto bad; 843 844 kmem_free(ph, phsize); 845 return 0; 846 847 bad: 848 if (interp) 849 PNBUF_PUT(interp); 850 exec_free_emul_arg(epp); 851 kmem_free(ph, phsize); 852 kill_vmcmds(&epp->ep_vmcmds); 853 return error; 854 } 855 856 int 857 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 858 Elf_Ehdr *eh) 859 { 860 size_t i; 861 Elf_Phdr *ph; 862 size_t phsize; 863 char *nbuf; 864 int error; 865 int isnetbsd = 0; 866 867 epp->ep_pax_flags = 0; 868 869 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) { 870 DPRINTF("no signature %#x", eh->e_phnum); 871 return ENOEXEC; 872 } 873 874 phsize = eh->e_phnum * sizeof(Elf_Phdr); 875 ph = kmem_alloc(phsize, KM_SLEEP); 876 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 877 if (error) 878 goto out; 879 880 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); 881 for (i = 0; i < eh->e_phnum; i++) { 882 const char *nptr; 883 size_t nlen; 884 885 if (ph[i].p_type != PT_NOTE || 886 ph[i].p_filesz > ELF_MAXNOTESIZE) 887 continue; 888 889 nlen = ph[i].p_filesz; 890 error = exec_read_from(l, epp->ep_vp, ph[i].p_offset, 891 nbuf, nlen); 892 if (error) 893 continue; 894 895 nptr = nbuf; 896 while (nlen > 0) { 897 const Elf_Nhdr *np; 898 const char *ndata, *ndesc; 899 900 /* note header */ 901 np = (const Elf_Nhdr *)nptr; 902 if (nlen < sizeof(*np)) { 903 break; 904 } 905 nptr += sizeof(*np); 906 nlen -= sizeof(*np); 907 908 /* note name */ 909 ndata = nptr; 910 if (nlen < roundup(np->n_namesz, 4)) { 911 break; 912 } 913 nptr += roundup(np->n_namesz, 4); 914 nlen -= roundup(np->n_namesz, 4); 915 916 /* note description */ 917 ndesc = nptr; 918 if (nlen < roundup(np->n_descsz, 4)) { 919 break; 920 } 921 nptr += roundup(np->n_descsz, 4); 922 nlen -= roundup(np->n_descsz, 4); 923 924 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc); 925 } 926 } 927 kmem_free(nbuf, ELF_MAXNOTESIZE); 928 929 error = isnetbsd ? 0 : ENOEXEC; 930 #ifdef DEBUG_ELF 931 if (error) 932 DPRINTF("not netbsd"); 933 #endif 934 out: 935 kmem_free(ph, phsize); 936 return error; 937 } 938 939 int 940 netbsd_elf_note(struct exec_package *epp, 941 const Elf_Nhdr *np, const char *ndata, const char *ndesc) 942 { 943 int isnetbsd = 0; 944 945 #ifdef DIAGNOSTIC 946 const char *badnote; 947 #define BADNOTE(n) badnote = (n) 948 #else 949 #define BADNOTE(n) 950 #endif 951 952 switch (np->n_type) { 953 case ELF_NOTE_TYPE_NETBSD_TAG: 954 /* It is us */ 955 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && 956 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && 957 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 958 ELF_NOTE_NETBSD_NAMESZ) == 0) { 959 memcpy(&epp->ep_osversion, ndesc, 960 ELF_NOTE_NETBSD_DESCSZ); 961 isnetbsd = 1; 962 break; 963 } 964 965 /* 966 * Ignore SuSE tags; SuSE's n_type is the same the 967 * NetBSD one. 968 */ 969 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && 970 memcmp(ndata, ELF_NOTE_SUSE_NAME, 971 ELF_NOTE_SUSE_NAMESZ) == 0) 972 break; 973 /* 974 * Ignore old GCC 975 */ 976 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && 977 memcmp(ndata, ELF_NOTE_OGCC_NAME, 978 ELF_NOTE_OGCC_NAMESZ) == 0) 979 break; 980 BADNOTE("NetBSD tag"); 981 goto bad; 982 983 case ELF_NOTE_TYPE_PAX_TAG: 984 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && 985 np->n_descsz == ELF_NOTE_PAX_DESCSZ && 986 memcmp(ndata, ELF_NOTE_PAX_NAME, 987 ELF_NOTE_PAX_NAMESZ) == 0) { 988 uint32_t flags; 989 memcpy(&flags, ndesc, sizeof(flags)); 990 /* Convert the flags and insert them into 991 * the exec package. */ 992 pax_setup_elf_flags(epp, flags); 993 break; 994 } 995 BADNOTE("PaX tag"); 996 goto bad; 997 998 case ELF_NOTE_TYPE_MARCH_TAG: 999 /* Copy the machine arch into the package. */ 1000 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ 1001 && memcmp(ndata, ELF_NOTE_MARCH_NAME, 1002 ELF_NOTE_MARCH_NAMESZ) == 0) { 1003 /* Do not truncate the buffer */ 1004 if (np->n_descsz > sizeof(epp->ep_machine_arch)) { 1005 BADNOTE("description size limit"); 1006 goto bad; 1007 } 1008 /* 1009 * Ensure ndesc is NUL-terminated and of the 1010 * expected length. 1011 */ 1012 if (strnlen(ndesc, np->n_descsz) + 1 != 1013 np->n_descsz) { 1014 BADNOTE("description size"); 1015 goto bad; 1016 } 1017 strlcpy(epp->ep_machine_arch, ndesc, 1018 sizeof(epp->ep_machine_arch)); 1019 break; 1020 } 1021 BADNOTE("march tag"); 1022 goto bad; 1023 1024 case ELF_NOTE_TYPE_MCMODEL_TAG: 1025 /* arch specific check for code model */ 1026 #ifdef ELF_MD_MCMODEL_CHECK 1027 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ 1028 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, 1029 ELF_NOTE_MCMODEL_NAMESZ) == 0) { 1030 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); 1031 break; 1032 } 1033 BADNOTE("mcmodel tag"); 1034 goto bad; 1035 #endif 1036 break; 1037 1038 case ELF_NOTE_TYPE_SUSE_VERSION_TAG: 1039 break; 1040 1041 case ELF_NOTE_TYPE_GO_BUILDID_TAG: 1042 break; 1043 1044 default: 1045 BADNOTE("unknown tag"); 1046 bad: 1047 #ifdef DIAGNOSTIC 1048 /* Ignore GNU tags */ 1049 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 1050 memcmp(ndata, ELF_NOTE_GNU_NAME, 1051 ELF_NOTE_GNU_NAMESZ) == 0) 1052 break; 1053 1054 int ns = (int)np->n_namesz; 1055 printf("%s: Unknown elf note type %d (%s): " 1056 "[namesz=%d, descsz=%d name=%-*.*s]\n", 1057 epp->ep_kname, np->n_type, badnote, np->n_namesz, 1058 np->n_descsz, ns, ns, ndata); 1059 #endif 1060 break; 1061 } 1062 1063 return isnetbsd; 1064 } 1065 1066 int 1067 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 1068 vaddr_t *pos) 1069 { 1070 int error; 1071 1072 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 1073 return error; 1074 #ifdef ELF_MD_PROBE_FUNC 1075 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 1076 return error; 1077 #elif defined(ELF_INTERP_NON_RELOCATABLE) 1078 *pos = ELF_LINK_ADDR; 1079 #endif 1080 epp->ep_flags |= EXEC_FORCEAUX; 1081 return 0; 1082 } 1083 1084 void 1085 elf_free_emul_arg(void *arg) 1086 { 1087 struct elf_args *ap = arg; 1088 KASSERT(ap != NULL); 1089 kmem_free(ap, sizeof(*ap)); 1090 } 1091