1 /* $NetBSD: exec_elf.c,v 1.101 2020/01/12 18:30:58 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1994, 2000, 2005, 2015, 2020 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 1.101 2020/01/12 18:30:58 ad 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_populate_auxv ELFNAME(populate_auxv) 93 #define elf_load_interp ELFNAME(load_interp) 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_note ELFNAME2(netbsd,note) 98 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 99 #define coredump ELFNAMEEND(coredump) 100 #define elf_free_emul_arg ELFNAME(free_emul_arg) 101 102 static int 103 elf_load_interp(struct lwp *, struct exec_package *, char *, 104 struct exec_vmcmd_set *, u_long *, Elf_Addr *); 105 static int 106 elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, 107 Elf_Addr *, u_long *, int); 108 109 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 110 int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *, 111 const char *); 112 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 113 vaddr_t *); 114 115 static void elf_free_emul_arg(void *); 116 117 #ifdef DEBUG_ELF 118 #define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__) 119 #else 120 #define DPRINTF(a, ...) 121 #endif 122 123 /* round up and down to page boundaries. */ 124 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 125 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 126 127 static int 128 elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph) 129 { 130 Elf_Addr align, offset; 131 int i; 132 133 for (align = 1, i = 0; i < eh->e_phnum; i++) 134 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 135 align = ph[i].p_align; 136 137 offset = (Elf_Addr)pax_aslr_exec_offset(epp, align); 138 if (offset < epp->ep_vm_minaddr) 139 offset = roundup(epp->ep_vm_minaddr, align); 140 if ((offset & (align - 1)) != 0) { 141 DPRINTF("bad offset=%#jx align=%#jx", 142 (uintmax_t)offset, (uintmax_t)align); 143 return EINVAL; 144 } 145 146 for (i = 0; i < eh->e_phnum; i++) 147 ph[i].p_vaddr += offset; 148 epp->ep_entryoffset = offset; 149 eh->e_entry += offset; 150 return 0; 151 } 152 153 154 int 155 elf_populate_auxv(struct lwp *l, struct exec_package *pack, char **stackp) 156 { 157 size_t len, vlen; 158 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 159 struct elf_args *ap; 160 char *path = l->l_proc->p_path; 161 int error; 162 163 execname = NULL; 164 a = ai; 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 /* "/" means fexecve(2) could not resolve the pathname */ 230 if (path[0] == '/' && path[1] != '\0') { 231 execname = a; 232 a->a_type = AT_SUN_EXECNAME; 233 a++; 234 } 235 236 exec_free_emul_arg(pack); 237 } 238 239 a->a_type = AT_NULL; 240 a->a_v = 0; 241 a++; 242 243 vlen = (a - ai) * sizeof(ai[0]); 244 245 KASSERT(vlen <= sizeof(ai)); 246 247 if (execname) { 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 } 256 257 if ((error = copyout(ai, *stackp, vlen)) != 0) 258 return error; 259 *stackp += vlen + len; 260 261 return 0; 262 } 263 264 /* 265 * Copy arguments onto the stack in the normal way, but add some 266 * extra information in case of dynamic binding. 267 */ 268 int 269 elf_copyargs(struct lwp *l, struct exec_package *pack, 270 struct ps_strings *arginfo, char **stackp, void *argp) 271 { 272 int error; 273 274 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 275 return error; 276 277 return elf_populate_auxv(l, pack, stackp); 278 } 279 280 /* 281 * elf_check_header(): 282 * 283 * Check header for validity; return 0 if ok, ENOEXEC if error 284 */ 285 int 286 elf_check_header(Elf_Ehdr *eh) 287 { 288 289 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 290 eh->e_ident[EI_CLASS] != ELFCLASS) { 291 DPRINTF("bad magic e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, " 292 "e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0], 293 eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2], 294 eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]); 295 return ENOEXEC; 296 } 297 298 switch (eh->e_machine) { 299 300 ELFDEFNNAME(MACHDEP_ID_CASES) 301 302 default: 303 DPRINTF("bad machine %#x", eh->e_machine); 304 return ENOEXEC; 305 } 306 307 if (ELF_EHDR_FLAGS_OK(eh) == 0) { 308 DPRINTF("bad flags %#x", eh->e_flags); 309 return ENOEXEC; 310 } 311 312 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { 313 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum); 314 return ENOEXEC; 315 } 316 317 return 0; 318 } 319 320 /* 321 * elf_load_psection(): 322 * 323 * Load a psection at the appropriate address 324 */ 325 static int 326 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 327 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) 328 { 329 u_long msize, psize, rm, rf; 330 long diff, offset; 331 int vmprot = 0; 332 333 KASSERT(VOP_ISLOCKED(vp) != LK_NONE); 334 335 /* 336 * If the user specified an address, then we load there. 337 */ 338 if (*addr == ELFDEFNNAME(NO_ADDR)) 339 *addr = ph->p_vaddr; 340 341 if (ph->p_align > 1) { 342 /* 343 * Make sure we are virtually aligned as we are supposed to be. 344 */ 345 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 346 if (*addr - diff != ELF_TRUNC(*addr, ph->p_align)) { 347 DPRINTF("bad alignment %#jx != %#jx\n", 348 (uintptr_t)(*addr - diff), 349 (uintptr_t)ELF_TRUNC(*addr, ph->p_align)); 350 return EINVAL; 351 } 352 /* 353 * But make sure to not map any pages before the start of the 354 * psection by limiting the difference to within a page. 355 */ 356 diff &= PAGE_MASK; 357 } else 358 diff = 0; 359 360 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 361 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 362 vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 363 364 /* 365 * Adjust everything so it all starts on a page boundary. 366 */ 367 *addr -= diff; 368 offset = ph->p_offset - diff; 369 *size = ph->p_filesz + diff; 370 msize = ph->p_memsz + diff; 371 372 if (ph->p_align >= PAGE_SIZE) { 373 if ((ph->p_flags & PF_W) != 0) { 374 /* 375 * Because the pagedvn pager can't handle zero fill 376 * of the last data page if it's not page aligned we 377 * map the last page readvn. 378 */ 379 psize = trunc_page(*size); 380 } else { 381 psize = round_page(*size); 382 } 383 } else { 384 psize = *size; 385 } 386 387 if (psize > 0) { 388 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 389 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 390 offset, vmprot, flags); 391 flags &= VMCMD_RELATIVE; 392 } 393 if (psize < *size) { 394 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 395 *addr + psize, vp, offset + psize, vmprot, flags); 396 } 397 398 /* 399 * Check if we need to extend the size of the segment (does 400 * bss extend page the next page boundary)? 401 */ 402 rm = round_page(*addr + msize); 403 rf = round_page(*addr + *size); 404 405 if (rm != rf) { 406 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 407 0, vmprot, flags & VMCMD_RELATIVE); 408 *size = msize; 409 } 410 return 0; 411 } 412 413 /* 414 * elf_load_interp(): 415 * 416 * Load an interpreter pointed to by path. 417 */ 418 static int 419 elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, 420 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) 421 { 422 int error, i; 423 struct vnode *vp; 424 struct vattr attr; 425 Elf_Ehdr eh; 426 Elf_Phdr *ph = NULL; 427 const Elf_Phdr *base_ph; 428 const Elf_Phdr *last_ph; 429 u_long phsize; 430 Elf_Addr addr = *last; 431 struct proc *p; 432 bool use_topdown; 433 434 p = l->l_proc; 435 436 KASSERT(p->p_vmspace); 437 KASSERT(p->p_vmspace != proc0.p_vmspace); 438 439 #ifdef __USE_TOPDOWN_VM 440 use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM; 441 #else 442 use_topdown = false; 443 #endif 444 445 /* 446 * 1. open file 447 * 2. read filehdr 448 * 3. map text, data, and bss out of it using VM_* 449 */ 450 vp = epp->ep_interp; 451 if (vp == NULL) { 452 error = emul_find_interp(l, epp, path); 453 if (error != 0) 454 return error; 455 vp = epp->ep_interp; 456 } 457 /* We'll tidy this ourselves - otherwise we have locking issues */ 458 epp->ep_interp = NULL; 459 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 460 461 /* 462 * Similarly, if it's not marked as executable, or it's not a regular 463 * file, we don't allow it to be used. 464 */ 465 if (vp->v_type != VREG) { 466 error = EACCES; 467 goto bad; 468 } 469 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 470 goto bad; 471 472 /* get attributes */ 473 /* XXX VOP_GETATTR() is the only thing that needs LK_EXCLUSIVE ^ */ 474 if ((error = VOP_GETATTR(vp, &attr, l->l_cred)) != 0) 475 goto bad; 476 477 /* 478 * Check mount point. Though we're not trying to exec this binary, 479 * we will be executing code from it, so if the mount point 480 * disallows execution or set-id-ness, we punt or kill the set-id. 481 */ 482 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 483 error = EACCES; 484 goto bad; 485 } 486 if (vp->v_mount->mnt_flag & MNT_NOSUID) 487 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 488 489 error = vn_marktext(vp); 490 if (error) 491 goto bad; 492 493 error = exec_read(l, vp, 0, &eh, sizeof(eh), IO_NODELOCKED); 494 if (error != 0) 495 goto bad; 496 497 if ((error = elf_check_header(&eh)) != 0) 498 goto bad; 499 if (eh.e_type != ET_DYN || eh.e_phnum == 0) { 500 DPRINTF("bad interpreter type %#x", eh.e_type); 501 error = ENOEXEC; 502 goto bad; 503 } 504 505 phsize = eh.e_phnum * sizeof(Elf_Phdr); 506 ph = kmem_alloc(phsize, KM_SLEEP); 507 508 error = exec_read(l, vp, eh.e_phoff, ph, phsize, IO_NODELOCKED); 509 if (error != 0) 510 goto bad; 511 512 #ifdef ELF_INTERP_NON_RELOCATABLE 513 /* 514 * Evil hack: Only MIPS should be non-relocatable, and the 515 * psections should have a high address (typically 0x5ffe0000). 516 * If it's now relocatable, it should be linked at 0 and the 517 * psections should have zeros in the upper part of the address. 518 * Otherwise, force the load at the linked address. 519 */ 520 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 521 *last = ELFDEFNNAME(NO_ADDR); 522 #endif 523 524 /* 525 * If no position to load the interpreter was set by a probe 526 * function, pick the same address that a non-fixed mmap(0, ..) 527 * would (i.e. something safely out of the way). 528 */ 529 if (*last == ELFDEFNNAME(NO_ADDR)) { 530 u_long limit = 0; 531 /* 532 * Find the start and ending addresses of the psections to 533 * be loaded. This will give us the size. 534 */ 535 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { 536 if (ph[i].p_type == PT_LOAD) { 537 u_long psize = ph[i].p_vaddr + ph[i].p_memsz; 538 if (base_ph == NULL) 539 base_ph = &ph[i]; 540 if (psize > limit) 541 limit = psize; 542 } 543 } 544 545 if (base_ph == NULL) { 546 DPRINTF("no interpreter loadable sections"); 547 error = ENOEXEC; 548 goto bad; 549 } 550 551 /* 552 * Now compute the size and load address. 553 */ 554 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 555 epp->ep_daddr, 556 round_page(limit) - trunc_page(base_ph->p_vaddr), 557 use_topdown); 558 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, 559 use_topdown); 560 } else { 561 addr = *last; /* may be ELF_LINK_ADDR */ 562 } 563 564 /* 565 * Load all the necessary sections 566 */ 567 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { 568 switch (ph[i].p_type) { 569 case PT_LOAD: { 570 u_long size; 571 int flags; 572 573 if (base_ph == NULL) { 574 /* 575 * First encountered psection is always the 576 * base psection. Make sure it's aligned 577 * properly (align down for topdown and align 578 * upwards for not topdown). 579 */ 580 base_ph = &ph[i]; 581 flags = VMCMD_BASE; 582 if (addr == ELF_LINK_ADDR) 583 addr = ph[i].p_vaddr; 584 if (use_topdown) 585 addr = ELF_TRUNC(addr, ph[i].p_align); 586 else 587 addr = ELF_ROUND(addr, ph[i].p_align); 588 } else { 589 u_long limit = round_page(last_ph->p_vaddr 590 + last_ph->p_memsz); 591 u_long base = trunc_page(ph[i].p_vaddr); 592 593 /* 594 * If there is a gap in between the psections, 595 * map it as inaccessible so nothing else 596 * mmap'ed will be placed there. 597 */ 598 if (limit != base) { 599 NEW_VMCMD2(vcset, vmcmd_map_zero, 600 base - limit, 601 limit - base_ph->p_vaddr, NULLVP, 602 0, VM_PROT_NONE, VMCMD_RELATIVE); 603 } 604 605 addr = ph[i].p_vaddr - base_ph->p_vaddr; 606 flags = VMCMD_RELATIVE; 607 } 608 last_ph = &ph[i]; 609 if ((error = elf_load_psection(vcset, vp, &ph[i], &addr, 610 &size, flags)) != 0) 611 goto bad; 612 /* 613 * If entry is within this psection then this 614 * must contain the .text section. *entryoff is 615 * relative to the base psection. 616 */ 617 if (eh.e_entry >= ph[i].p_vaddr && 618 eh.e_entry < (ph[i].p_vaddr + size)) { 619 *entryoff = eh.e_entry - base_ph->p_vaddr; 620 } 621 addr += size; 622 break; 623 } 624 625 default: 626 break; 627 } 628 } 629 630 kmem_free(ph, phsize); 631 /* 632 * This value is ignored if TOPDOWN. 633 */ 634 *last = addr; 635 vput(vp); 636 return 0; 637 638 bad: 639 if (ph != NULL) 640 kmem_free(ph, phsize); 641 vput(vp); 642 return error; 643 } 644 645 /* 646 * exec_elf_makecmds(): Prepare an Elf binary's exec package 647 * 648 * First, set of the various offsets/lengths in the exec package. 649 * 650 * Then, mark the text image busy (so it can be demand paged) or error 651 * out if this is not possible. Finally, set up vmcmds for the 652 * text, data, bss, and stack segments. 653 */ 654 int 655 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 656 { 657 Elf_Ehdr *eh = epp->ep_hdr; 658 Elf_Phdr *ph, *pp; 659 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 660 int error, i; 661 char *interp = NULL; 662 u_long phsize; 663 struct elf_args *ap; 664 bool is_dyn = false; 665 666 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { 667 DPRINTF("small header %#x", epp->ep_hdrvalid); 668 return ENOEXEC; 669 } 670 if ((error = elf_check_header(eh)) != 0) 671 return error; 672 673 if (eh->e_type == ET_DYN) 674 /* PIE, and some libs have an entry point */ 675 is_dyn = true; 676 else if (eh->e_type != ET_EXEC) { 677 DPRINTF("bad type %#x", eh->e_type); 678 return ENOEXEC; 679 } 680 681 if (eh->e_phnum == 0) { 682 DPRINTF("no program headers"); 683 return ENOEXEC; 684 } 685 686 /* XXX only LK_EXCLUSIVE to match all others - allow spinning */ 687 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 688 error = vn_marktext(epp->ep_vp); 689 if (error) { 690 VOP_UNLOCK(epp->ep_vp); 691 return error; 692 } 693 694 /* 695 * Allocate space to hold all the program headers, and read them 696 * from the file 697 */ 698 phsize = eh->e_phnum * sizeof(Elf_Phdr); 699 ph = kmem_alloc(phsize, KM_SLEEP); 700 701 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 702 IO_NODELOCKED); 703 if (error != 0) { 704 VOP_UNLOCK(epp->ep_vp); 705 goto bad; 706 } 707 708 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 709 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 710 711 for (i = 0; i < eh->e_phnum; i++) { 712 pp = &ph[i]; 713 if (pp->p_type == PT_INTERP) { 714 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { 715 DPRINTF("bad interpreter namelen %#jx", 716 (uintmax_t)pp->p_filesz); 717 error = ENOEXEC; 718 VOP_UNLOCK(epp->ep_vp); 719 goto bad; 720 } 721 interp = PNBUF_GET(); 722 error = exec_read(l, epp->ep_vp, pp->p_offset, interp, 723 pp->p_filesz, IO_NODELOCKED); 724 if (error != 0) { 725 VOP_UNLOCK(epp->ep_vp); 726 goto bad; 727 } 728 /* Ensure interp is NUL-terminated and of the expected length */ 729 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { 730 DPRINTF("bad interpreter name"); 731 error = ENOEXEC; 732 VOP_UNLOCK(epp->ep_vp); 733 goto bad; 734 } 735 break; 736 } 737 } 738 739 /* 740 * On the same architecture, we may be emulating different systems. 741 * See which one will accept this executable. 742 * 743 * Probe functions would normally see if the interpreter (if any) 744 * exists. Emulation packages may possibly replace the interpreter in 745 * interp with a changed path (/emul/xxx/<path>). 746 */ 747 pos = ELFDEFNNAME(NO_ADDR); 748 if (epp->ep_esch->u.elf_probe_func) { 749 vaddr_t startp = (vaddr_t)pos; 750 751 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 752 &startp); 753 if (error) { 754 VOP_UNLOCK(epp->ep_vp); 755 goto bad; 756 } 757 pos = (Elf_Addr)startp; 758 } 759 760 if (is_dyn && (error = elf_placedynexec(epp, eh, ph)) != 0) { 761 VOP_UNLOCK(epp->ep_vp); 762 goto bad; 763 } 764 765 /* 766 * Load all the necessary sections 767 */ 768 for (i = 0; i < eh->e_phnum; i++) { 769 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 770 u_long size = 0; 771 772 switch (ph[i].p_type) { 773 case PT_LOAD: 774 if ((error = elf_load_psection(&epp->ep_vmcmds, 775 epp->ep_vp, &ph[i], &addr, &size, VMCMD_FIXED)) 776 != 0) { 777 VOP_UNLOCK(epp->ep_vp); 778 goto bad; 779 } 780 781 /* 782 * Consider this as text segment, if it is executable. 783 * If there is more than one text segment, pick the 784 * largest. 785 */ 786 if (ph[i].p_flags & PF_X) { 787 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 788 size > epp->ep_tsize) { 789 epp->ep_taddr = addr; 790 epp->ep_tsize = size; 791 } 792 end_text = addr + size; 793 } else { 794 epp->ep_daddr = addr; 795 epp->ep_dsize = size; 796 } 797 if (ph[i].p_offset == 0) { 798 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 799 } 800 break; 801 802 case PT_SHLIB: 803 /* SCO has these sections. */ 804 case PT_INTERP: 805 /* Already did this one. */ 806 case PT_DYNAMIC: 807 case PT_NOTE: 808 break; 809 case PT_PHDR: 810 /* Note address of program headers (in text segment) */ 811 phdr = ph[i].p_vaddr; 812 break; 813 814 default: 815 /* 816 * Not fatal; we don't need to understand everything. 817 */ 818 break; 819 } 820 } 821 822 /* Now done with the vnode. */ 823 VOP_UNLOCK(epp->ep_vp); 824 825 if (epp->ep_vmcmds.evs_used == 0) { 826 /* No VMCMD; there was no PT_LOAD section, or those 827 * sections were empty */ 828 DPRINTF("no vmcommands"); 829 error = ENOEXEC; 830 goto bad; 831 } 832 833 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 834 epp->ep_daddr = round_page(end_text); 835 epp->ep_dsize = 0; 836 } 837 838 /* 839 * Check if we found a dynamically linked binary and arrange to load 840 * its interpreter 841 */ 842 if (interp) { 843 u_int nused = epp->ep_vmcmds.evs_used; 844 u_long interp_offset = 0; 845 846 if ((error = elf_load_interp(l, epp, interp, 847 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { 848 goto bad; 849 } 850 if (epp->ep_vmcmds.evs_used == nused) { 851 /* elf_load_interp() has not set up any new VMCMD */ 852 DPRINTF("no vmcommands for interpreter"); 853 error = ENOEXEC; 854 goto bad; 855 } 856 857 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 858 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; 859 epp->ep_entryoffset = interp_offset; 860 epp->ep_entry = ap->arg_interp + interp_offset; 861 PNBUF_PUT(interp); 862 interp = NULL; 863 } else { 864 epp->ep_entry = eh->e_entry; 865 if (epp->ep_flags & EXEC_FORCEAUX) { 866 ap = kmem_zalloc(sizeof(*ap), KM_SLEEP); 867 ap->arg_interp = (vaddr_t)NULL; 868 } else { 869 ap = NULL; 870 } 871 } 872 873 if (ap) { 874 ap->arg_phaddr = phdr ? phdr : computed_phdr; 875 ap->arg_phentsize = eh->e_phentsize; 876 ap->arg_phnum = eh->e_phnum; 877 ap->arg_entry = eh->e_entry; 878 epp->ep_emul_arg = ap; 879 epp->ep_emul_arg_free = elf_free_emul_arg; 880 } 881 882 #ifdef ELF_MAP_PAGE_ZERO 883 /* Dell SVR4 maps page zero, yeuch! */ 884 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 885 epp->ep_vp, 0, VM_PROT_READ); 886 #endif 887 888 error = (*epp->ep_esch->es_setup_stack)(l, epp); 889 if (error) 890 goto bad; 891 892 kmem_free(ph, phsize); 893 return 0; 894 895 bad: 896 if (interp) 897 PNBUF_PUT(interp); 898 exec_free_emul_arg(epp); 899 kmem_free(ph, phsize); 900 kill_vmcmds(&epp->ep_vmcmds); 901 return error; 902 } 903 904 int 905 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 906 Elf_Ehdr *eh) 907 { 908 size_t i; 909 Elf_Phdr *ph; 910 size_t phsize; 911 char *nbuf; 912 int error; 913 int isnetbsd = 0; 914 915 epp->ep_pax_flags = 0; 916 917 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) { 918 DPRINTF("no signature %#x", eh->e_phnum); 919 return ENOEXEC; 920 } 921 922 phsize = eh->e_phnum * sizeof(Elf_Phdr); 923 ph = kmem_alloc(phsize, KM_SLEEP); 924 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 925 IO_NODELOCKED); 926 if (error) 927 goto out; 928 929 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); 930 for (i = 0; i < eh->e_phnum; i++) { 931 const char *nptr; 932 size_t nlen; 933 934 if (ph[i].p_type != PT_NOTE || 935 ph[i].p_filesz > ELF_MAXNOTESIZE) 936 continue; 937 938 nlen = ph[i].p_filesz; 939 error = exec_read(l, epp->ep_vp, ph[i].p_offset, nbuf, nlen, 940 IO_NODELOCKED); 941 if (error) 942 continue; 943 944 nptr = nbuf; 945 while (nlen > 0) { 946 const Elf_Nhdr *np; 947 const char *ndata, *ndesc; 948 949 /* note header */ 950 np = (const Elf_Nhdr *)nptr; 951 if (nlen < sizeof(*np)) { 952 break; 953 } 954 nptr += sizeof(*np); 955 nlen -= sizeof(*np); 956 957 /* note name */ 958 ndata = nptr; 959 if (nlen < roundup(np->n_namesz, 4)) { 960 break; 961 } 962 nptr += roundup(np->n_namesz, 4); 963 nlen -= roundup(np->n_namesz, 4); 964 965 /* note description */ 966 ndesc = nptr; 967 if (nlen < roundup(np->n_descsz, 4)) { 968 break; 969 } 970 nptr += roundup(np->n_descsz, 4); 971 nlen -= roundup(np->n_descsz, 4); 972 973 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc); 974 } 975 } 976 kmem_free(nbuf, ELF_MAXNOTESIZE); 977 978 error = isnetbsd ? 0 : ENOEXEC; 979 #ifdef DEBUG_ELF 980 if (error) 981 DPRINTF("not netbsd"); 982 #endif 983 out: 984 kmem_free(ph, phsize); 985 return error; 986 } 987 988 int 989 netbsd_elf_note(struct exec_package *epp, 990 const Elf_Nhdr *np, const char *ndata, const char *ndesc) 991 { 992 int isnetbsd = 0; 993 994 #ifdef DIAGNOSTIC 995 const char *badnote; 996 #define BADNOTE(n) badnote = (n) 997 #else 998 #define BADNOTE(n) 999 #endif 1000 1001 switch (np->n_type) { 1002 case ELF_NOTE_TYPE_NETBSD_TAG: 1003 /* It is us */ 1004 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && 1005 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && 1006 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 1007 ELF_NOTE_NETBSD_NAMESZ) == 0) { 1008 memcpy(&epp->ep_osversion, ndesc, 1009 ELF_NOTE_NETBSD_DESCSZ); 1010 isnetbsd = 1; 1011 break; 1012 } 1013 1014 /* 1015 * Ignore SuSE tags; SuSE's n_type is the same the 1016 * NetBSD one. 1017 */ 1018 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && 1019 memcmp(ndata, ELF_NOTE_SUSE_NAME, 1020 ELF_NOTE_SUSE_NAMESZ) == 0) 1021 break; 1022 /* 1023 * Ignore old GCC 1024 */ 1025 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && 1026 memcmp(ndata, ELF_NOTE_OGCC_NAME, 1027 ELF_NOTE_OGCC_NAMESZ) == 0) 1028 break; 1029 BADNOTE("NetBSD tag"); 1030 goto bad; 1031 1032 case ELF_NOTE_TYPE_PAX_TAG: 1033 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && 1034 np->n_descsz == ELF_NOTE_PAX_DESCSZ && 1035 memcmp(ndata, ELF_NOTE_PAX_NAME, 1036 ELF_NOTE_PAX_NAMESZ) == 0) { 1037 uint32_t flags; 1038 memcpy(&flags, ndesc, sizeof(flags)); 1039 /* Convert the flags and insert them into 1040 * the exec package. */ 1041 pax_setup_elf_flags(epp, flags); 1042 break; 1043 } 1044 BADNOTE("PaX tag"); 1045 goto bad; 1046 1047 case ELF_NOTE_TYPE_MARCH_TAG: 1048 /* Copy the machine arch into the package. */ 1049 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ 1050 && memcmp(ndata, ELF_NOTE_MARCH_NAME, 1051 ELF_NOTE_MARCH_NAMESZ) == 0) { 1052 /* Do not truncate the buffer */ 1053 if (np->n_descsz > sizeof(epp->ep_machine_arch)) { 1054 BADNOTE("description size limit"); 1055 goto bad; 1056 } 1057 /* 1058 * Ensure ndesc is NUL-terminated and of the 1059 * expected length. 1060 */ 1061 if (strnlen(ndesc, np->n_descsz) + 1 != 1062 np->n_descsz) { 1063 BADNOTE("description size"); 1064 goto bad; 1065 } 1066 strlcpy(epp->ep_machine_arch, ndesc, 1067 sizeof(epp->ep_machine_arch)); 1068 break; 1069 } 1070 BADNOTE("march tag"); 1071 goto bad; 1072 1073 case ELF_NOTE_TYPE_MCMODEL_TAG: 1074 /* arch specific check for code model */ 1075 #ifdef ELF_MD_MCMODEL_CHECK 1076 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ 1077 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, 1078 ELF_NOTE_MCMODEL_NAMESZ) == 0) { 1079 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); 1080 break; 1081 } 1082 BADNOTE("mcmodel tag"); 1083 goto bad; 1084 #endif 1085 break; 1086 1087 case ELF_NOTE_TYPE_SUSE_VERSION_TAG: 1088 break; 1089 1090 case ELF_NOTE_TYPE_GO_BUILDID_TAG: 1091 break; 1092 1093 case ELF_NOTE_TYPE_NETBSD_EMUL_TAG: 1094 /* Ancient NetBSD version tag */ 1095 break; 1096 1097 default: 1098 BADNOTE("unknown tag"); 1099 bad: 1100 #ifdef DIAGNOSTIC 1101 /* Ignore GNU tags */ 1102 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 1103 memcmp(ndata, ELF_NOTE_GNU_NAME, 1104 ELF_NOTE_GNU_NAMESZ) == 0) 1105 break; 1106 1107 int ns = (int)np->n_namesz; 1108 printf("%s: Unknown elf note type %d (%s): " 1109 "[namesz=%d, descsz=%d name=%-*.*s]\n", 1110 epp->ep_kname, np->n_type, badnote, np->n_namesz, 1111 np->n_descsz, ns, ns, ndata); 1112 #endif 1113 break; 1114 } 1115 1116 return isnetbsd; 1117 } 1118 1119 int 1120 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 1121 vaddr_t *pos) 1122 { 1123 int error; 1124 1125 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 1126 return error; 1127 #ifdef ELF_MD_PROBE_FUNC 1128 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 1129 return error; 1130 #elif defined(ELF_INTERP_NON_RELOCATABLE) 1131 *pos = ELF_LINK_ADDR; 1132 #endif 1133 epp->ep_flags |= EXEC_FORCEAUX; 1134 return 0; 1135 } 1136 1137 void 1138 elf_free_emul_arg(void *arg) 1139 { 1140 struct elf_args *ap = arg; 1141 KASSERT(ap != NULL); 1142 kmem_free(ap, sizeof(*ap)); 1143 } 1144