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FreeBSD/Linux Kernel Cross Reference
sys/kern/exec_elf.c
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1 /* $NetBSD: exec_elf.c,v 1.104 2022/10/26 23:20:36 riastradh 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 1.104 2022/10/26 23:20:36 riastradh 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 #define elf_check_header ELFNAME(check_header) 89 #define elf_copyargs ELFNAME(copyargs) 90 #define elf_populate_auxv ELFNAME(populate_auxv) 91 #define elf_load_interp ELFNAME(load_interp) 92 #define elf_load_psection ELFNAME(load_psection) 93 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 94 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 95 #define netbsd_elf_note ELFNAME2(netbsd,note) 96 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 97 #define coredump ELFNAMEEND(coredump) 98 #define elf_free_emul_arg ELFNAME(free_emul_arg) 99 100 static int 101 elf_load_interp(struct lwp *, struct exec_package *, char *, 102 struct exec_vmcmd_set *, u_long *, Elf_Addr *); 103 static int 104 elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, 105 Elf_Addr *, u_long *, int); 106 107 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 108 int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *, 109 const char *); 110 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 111 vaddr_t *); 112 113 static void elf_free_emul_arg(void *); 114 115 #ifdef DEBUG_ELF 116 #define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__) 117 #else 118 #define DPRINTF(a, ...) 119 #endif 120 121 /* round up and down to page boundaries. */ 122 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 123 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 124 125 static int 126 elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph) 127 { 128 Elf_Addr align, offset; 129 int i; 130 131 for (align = 1, i = 0; i < eh->e_phnum; i++) 132 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 133 align = ph[i].p_align; 134 135 offset = (Elf_Addr)pax_aslr_exec_offset(epp, align); 136 if (offset < epp->ep_vm_minaddr) 137 offset = roundup(epp->ep_vm_minaddr, align); 138 if ((offset & (align - 1)) != 0) { 139 DPRINTF("bad offset=%#jx align=%#jx", 140 (uintmax_t)offset, (uintmax_t)align); 141 return EINVAL; 142 } 143 144 for (i = 0; i < eh->e_phnum; i++) 145 ph[i].p_vaddr += offset; 146 epp->ep_entryoffset = offset; 147 eh->e_entry += offset; 148 return 0; 149 } 150 151 152 int 153 elf_populate_auxv(struct lwp *l, struct exec_package *pack, char **stackp) 154 { 155 size_t len, vlen; 156 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 157 struct elf_args *ap; 158 char *path = l->l_proc->p_path; 159 int error; 160 161 execname = NULL; 162 a = ai; 163 164 memset(ai, 0, sizeof(ai)); 165 166 /* 167 * Push extra arguments on the stack needed by dynamically 168 * linked binaries 169 */ 170 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 171 struct vattr *vap = pack->ep_vap; 172 173 a->a_type = AT_PHDR; 174 a->a_v = ap->arg_phaddr; 175 a++; 176 177 a->a_type = AT_PHENT; 178 a->a_v = ap->arg_phentsize; 179 a++; 180 181 a->a_type = AT_PHNUM; 182 a->a_v = ap->arg_phnum; 183 a++; 184 185 a->a_type = AT_PAGESZ; 186 a->a_v = PAGE_SIZE; 187 a++; 188 189 a->a_type = AT_BASE; 190 a->a_v = ap->arg_interp; 191 a++; 192 193 a->a_type = AT_FLAGS; 194 a->a_v = 0; 195 a++; 196 197 a->a_type = AT_ENTRY; 198 a->a_v = ap->arg_entry; 199 a++; 200 201 a->a_type = AT_EUID; 202 if (vap->va_mode & S_ISUID) 203 a->a_v = vap->va_uid; 204 else 205 a->a_v = kauth_cred_geteuid(l->l_cred); 206 a++; 207 208 a->a_type = AT_RUID; 209 a->a_v = kauth_cred_getuid(l->l_cred); 210 a++; 211 212 a->a_type = AT_EGID; 213 if (vap->va_mode & S_ISGID) 214 a->a_v = vap->va_gid; 215 else 216 a->a_v = kauth_cred_getegid(l->l_cred); 217 a++; 218 219 a->a_type = AT_RGID; 220 a->a_v = kauth_cred_getgid(l->l_cred); 221 a++; 222 223 a->a_type = AT_STACKBASE; 224 a->a_v = l->l_proc->p_stackbase; 225 a++; 226 227 /* "/" means fexecve(2) could not resolve the pathname */ 228 if (path[0] == '/' && path[1] != '\0') { 229 execname = a; 230 a->a_type = AT_SUN_EXECNAME; 231 a++; 232 } 233 234 exec_free_emul_arg(pack); 235 } 236 237 a->a_type = AT_NULL; 238 a->a_v = 0; 239 a++; 240 241 vlen = (a - ai) * sizeof(ai[0]); 242 243 KASSERT(vlen <= sizeof(ai)); 244 245 if (execname) { 246 execname->a_v = (uintptr_t)(*stackp + vlen); 247 len = strlen(path) + 1; 248 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 249 return error; 250 len = ALIGN(len); 251 } else { 252 len = 0; 253 } 254 255 if ((error = copyout(ai, *stackp, vlen)) != 0) 256 return error; 257 *stackp += vlen + len; 258 259 return 0; 260 } 261 262 /* 263 * Copy arguments onto the stack in the normal way, but add some 264 * extra information in case of dynamic binding. 265 */ 266 int 267 elf_copyargs(struct lwp *l, struct exec_package *pack, 268 struct ps_strings *arginfo, char **stackp, void *argp) 269 { 270 int error; 271 272 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 273 return error; 274 275 return elf_populate_auxv(l, pack, stackp); 276 } 277 278 /* 279 * elf_check_header(): 280 * 281 * Check header for validity; return 0 if ok, ENOEXEC if error 282 */ 283 int 284 elf_check_header(Elf_Ehdr *eh) 285 { 286 287 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 288 eh->e_ident[EI_CLASS] != ELFCLASS) { 289 DPRINTF("bad magic e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, " 290 "e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0], 291 eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2], 292 eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]); 293 return ENOEXEC; 294 } 295 296 switch (eh->e_machine) { 297 298 ELFDEFNNAME(MACHDEP_ID_CASES) 299 300 default: 301 DPRINTF("bad machine %#x", eh->e_machine); 302 return ENOEXEC; 303 } 304 305 if (ELF_EHDR_FLAGS_OK(eh) == 0) { 306 DPRINTF("bad flags %#x", eh->e_flags); 307 return ENOEXEC; 308 } 309 310 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { 311 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum); 312 return ENOEXEC; 313 } 314 315 return 0; 316 } 317 318 /* 319 * elf_load_psection(): 320 * 321 * Load a psection at the appropriate address 322 */ 323 static int 324 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 325 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) 326 { 327 u_long msize, psize, rm, rf; 328 long diff, offset; 329 int vmprot = 0; 330 331 KASSERT(VOP_ISLOCKED(vp) != LK_NONE); 332 333 /* 334 * If the user specified an address, then we load there. 335 */ 336 if (*addr == ELFDEFNNAME(NO_ADDR)) 337 *addr = ph->p_vaddr; 338 339 if (ph->p_align > 1) { 340 /* 341 * Make sure we are virtually aligned as we are supposed to be. 342 */ 343 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 344 if (*addr - diff != ELF_TRUNC(*addr, ph->p_align)) { 345 DPRINTF("bad alignment %#jx != %#jx\n", 346 (uintptr_t)(*addr - diff), 347 (uintptr_t)ELF_TRUNC(*addr, ph->p_align)); 348 return EINVAL; 349 } 350 /* 351 * But make sure to not map any pages before the start of the 352 * psection by limiting the difference to within a page. 353 */ 354 diff &= PAGE_MASK; 355 } else 356 diff = 0; 357 358 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 359 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 360 vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 361 362 /* 363 * Adjust everything so it all starts on a page boundary. 364 */ 365 *addr -= diff; 366 offset = ph->p_offset - diff; 367 *size = ph->p_filesz + diff; 368 msize = ph->p_memsz + diff; 369 370 if (ph->p_align >= PAGE_SIZE) { 371 if ((ph->p_flags & PF_W) != 0) { 372 /* 373 * Because the pagedvn pager can't handle zero fill 374 * of the last data page if it's not page aligned we 375 * map the last page readvn. 376 */ 377 psize = trunc_page(*size); 378 } else { 379 psize = round_page(*size); 380 } 381 } else { 382 psize = *size; 383 } 384 385 if (psize > 0) { 386 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 387 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 388 offset, vmprot, flags); 389 flags &= VMCMD_RELATIVE; 390 } 391 if (psize < *size) { 392 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 393 *addr + psize, vp, offset + psize, vmprot, flags); 394 } 395 396 /* 397 * Check if we need to extend the size of the segment (does 398 * bss extend page the next page boundary)? 399 */ 400 rm = round_page(*addr + msize); 401 rf = round_page(*addr + *size); 402 403 if (rm != rf) { 404 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 405 0, vmprot, flags & VMCMD_RELATIVE); 406 *size = msize; 407 } 408 return 0; 409 } 410 411 /* 412 * elf_load_interp(): 413 * 414 * Load an interpreter pointed to by path. 415 */ 416 static int 417 elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, 418 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) 419 { 420 int error, i; 421 struct vnode *vp; 422 Elf_Ehdr eh; 423 Elf_Phdr *ph = NULL; 424 const Elf_Phdr *base_ph; 425 const Elf_Phdr *last_ph; 426 u_long phsize; 427 Elf_Addr addr = *last; 428 struct proc *p; 429 bool use_topdown; 430 431 p = l->l_proc; 432 433 KASSERT(p->p_vmspace); 434 KASSERT(p->p_vmspace != proc0.p_vmspace); 435 436 #ifdef __USE_TOPDOWN_VM 437 use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM; 438 #else 439 use_topdown = false; 440 #endif 441 442 /* 443 * 1. open file 444 * 2. read filehdr 445 * 3. map text, data, and bss out of it using VM_* 446 */ 447 vp = epp->ep_interp; 448 if (vp == NULL) { 449 error = emul_find_interp(l, epp, path); 450 if (error != 0) 451 return error; 452 vp = epp->ep_interp; 453 } 454 /* We'll tidy this ourselves - otherwise we have locking issues */ 455 epp->ep_interp = NULL; 456 vn_lock(vp, LK_SHARED | LK_RETRY); 457 458 /* 459 * Similarly, if it's not marked as executable, or it's not a regular 460 * file, we don't allow it to be used. 461 */ 462 if (vp->v_type != VREG) { 463 error = EACCES; 464 goto bad; 465 } 466 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 467 goto bad; 468 469 /* 470 * Check mount point. Though we're not trying to exec this binary, 471 * we will be executing code from it, so if the mount point 472 * disallows execution or set-id-ness, we punt or kill the set-id. 473 */ 474 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 475 error = EACCES; 476 goto bad; 477 } 478 if (vp->v_mount->mnt_flag & MNT_NOSUID) 479 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 480 481 error = vn_marktext(vp); 482 if (error) 483 goto bad; 484 485 error = exec_read(l, vp, 0, &eh, sizeof(eh), IO_NODELOCKED); 486 if (error != 0) 487 goto bad; 488 489 if ((error = elf_check_header(&eh)) != 0) 490 goto bad; 491 if (eh.e_type != ET_DYN || eh.e_phnum == 0) { 492 DPRINTF("bad interpreter type %#x", eh.e_type); 493 error = ENOEXEC; 494 goto bad; 495 } 496 497 phsize = eh.e_phnum * sizeof(Elf_Phdr); 498 ph = kmem_alloc(phsize, KM_SLEEP); 499 500 error = exec_read(l, vp, eh.e_phoff, ph, phsize, IO_NODELOCKED); 501 if (error != 0) 502 goto bad; 503 504 #ifdef ELF_INTERP_NON_RELOCATABLE 505 /* 506 * Evil hack: Only MIPS should be non-relocatable, and the 507 * psections should have a high address (typically 0x5ffe0000). 508 * If it's now relocatable, it should be linked at 0 and the 509 * psections should have zeros in the upper part of the address. 510 * Otherwise, force the load at the linked address. 511 */ 512 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 513 *last = ELFDEFNNAME(NO_ADDR); 514 #endif 515 516 /* 517 * If no position to load the interpreter was set by a probe 518 * function, pick the same address that a non-fixed mmap(0, ..) 519 * would (i.e. something safely out of the way). 520 */ 521 if (*last == ELFDEFNNAME(NO_ADDR)) { 522 u_long limit = 0; 523 /* 524 * Find the start and ending addresses of the psections to 525 * be loaded. This will give us the size. 526 */ 527 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { 528 if (ph[i].p_type == PT_LOAD) { 529 u_long psize = ph[i].p_vaddr + ph[i].p_memsz; 530 if (base_ph == NULL) 531 base_ph = &ph[i]; 532 if (psize > limit) 533 limit = psize; 534 } 535 } 536 537 if (base_ph == NULL) { 538 DPRINTF("no interpreter loadable sections"); 539 error = ENOEXEC; 540 goto bad; 541 } 542 543 /* 544 * Now compute the size and load address. 545 */ 546 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 547 epp->ep_daddr, 548 round_page(limit) - trunc_page(base_ph->p_vaddr), 549 use_topdown); 550 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, 551 use_topdown); 552 } else { 553 addr = *last; /* may be ELF_LINK_ADDR */ 554 } 555 556 /* 557 * Load all the necessary sections 558 */ 559 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { 560 switch (ph[i].p_type) { 561 case PT_LOAD: { 562 u_long size; 563 int flags; 564 565 if (base_ph == NULL) { 566 /* 567 * First encountered psection is always the 568 * base psection. Make sure it's aligned 569 * properly (align down for topdown and align 570 * upwards for not topdown). 571 */ 572 base_ph = &ph[i]; 573 flags = VMCMD_BASE; 574 if (addr == ELF_LINK_ADDR) 575 addr = ph[i].p_vaddr; 576 if (use_topdown) 577 addr = ELF_TRUNC(addr, ph[i].p_align); 578 else 579 addr = ELF_ROUND(addr, ph[i].p_align); 580 } else { 581 u_long limit = round_page(last_ph->p_vaddr 582 + last_ph->p_memsz); 583 u_long base = trunc_page(ph[i].p_vaddr); 584 585 /* 586 * If there is a gap in between the psections, 587 * map it as inaccessible so nothing else 588 * mmap'ed will be placed there. 589 */ 590 if (limit != base) { 591 NEW_VMCMD2(vcset, vmcmd_map_zero, 592 base - limit, 593 limit - base_ph->p_vaddr, NULLVP, 594 0, VM_PROT_NONE, VMCMD_RELATIVE); 595 } 596 597 addr = ph[i].p_vaddr - base_ph->p_vaddr; 598 flags = VMCMD_RELATIVE; 599 } 600 last_ph = &ph[i]; 601 if ((error = elf_load_psection(vcset, vp, &ph[i], &addr, 602 &size, flags)) != 0) 603 goto bad; 604 /* 605 * If entry is within this psection then this 606 * must contain the .text section. *entryoff is 607 * relative to the base psection. 608 */ 609 if (eh.e_entry >= ph[i].p_vaddr && 610 eh.e_entry < (ph[i].p_vaddr + size)) { 611 *entryoff = eh.e_entry - base_ph->p_vaddr; 612 } 613 addr += size; 614 break; 615 } 616 617 default: 618 break; 619 } 620 } 621 622 kmem_free(ph, phsize); 623 /* 624 * This value is ignored if TOPDOWN. 625 */ 626 *last = addr; 627 vput(vp); 628 return 0; 629 630 bad: 631 if (ph != NULL) 632 kmem_free(ph, phsize); 633 vput(vp); 634 return error; 635 } 636 637 /* 638 * exec_elf_makecmds(): Prepare an Elf binary's exec package 639 * 640 * First, set of the various offsets/lengths in the exec package. 641 * 642 * Then, mark the text image busy (so it can be demand paged) or error 643 * out if this is not possible. Finally, set up vmcmds for the 644 * text, data, bss, and stack segments. 645 */ 646 int 647 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 648 { 649 Elf_Ehdr *eh = epp->ep_hdr; 650 Elf_Phdr *ph, *pp; 651 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 652 int error, i; 653 char *interp = NULL; 654 u_long phsize; 655 struct elf_args *ap; 656 bool is_dyn = false; 657 658 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { 659 DPRINTF("small header %#x", epp->ep_hdrvalid); 660 return ENOEXEC; 661 } 662 if ((error = elf_check_header(eh)) != 0) 663 return error; 664 665 if (eh->e_type == ET_DYN) 666 /* PIE, and some libs have an entry point */ 667 is_dyn = true; 668 else if (eh->e_type != ET_EXEC) { 669 DPRINTF("bad type %#x", eh->e_type); 670 return ENOEXEC; 671 } 672 673 if (eh->e_phnum == 0) { 674 DPRINTF("no program headers"); 675 return ENOEXEC; 676 } 677 678 /* XXX only LK_EXCLUSIVE to match all others - allow spinning */ 679 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 680 error = vn_marktext(epp->ep_vp); 681 if (error) { 682 VOP_UNLOCK(epp->ep_vp); 683 return error; 684 } 685 686 /* 687 * Allocate space to hold all the program headers, and read them 688 * from the file 689 */ 690 phsize = eh->e_phnum * sizeof(Elf_Phdr); 691 ph = kmem_alloc(phsize, KM_SLEEP); 692 693 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 694 IO_NODELOCKED); 695 if (error != 0) { 696 VOP_UNLOCK(epp->ep_vp); 697 goto bad; 698 } 699 700 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 701 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 702 703 for (i = 0; i < eh->e_phnum; i++) { 704 pp = &ph[i]; 705 if (pp->p_type == PT_INTERP) { 706 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { 707 DPRINTF("bad interpreter namelen %#jx", 708 (uintmax_t)pp->p_filesz); 709 error = ENOEXEC; 710 VOP_UNLOCK(epp->ep_vp); 711 goto bad; 712 } 713 interp = PNBUF_GET(); 714 error = exec_read(l, epp->ep_vp, pp->p_offset, interp, 715 pp->p_filesz, IO_NODELOCKED); 716 if (error != 0) { 717 VOP_UNLOCK(epp->ep_vp); 718 goto bad; 719 } 720 /* Ensure interp is NUL-terminated and of the expected length */ 721 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { 722 DPRINTF("bad interpreter name"); 723 error = ENOEXEC; 724 VOP_UNLOCK(epp->ep_vp); 725 goto bad; 726 } 727 break; 728 } 729 } 730 731 /* 732 * On the same architecture, we may be emulating different systems. 733 * See which one will accept this executable. 734 * 735 * Probe functions would normally see if the interpreter (if any) 736 * exists. Emulation packages may possibly replace the interpreter in 737 * interp with a changed path (/emul/xxx/<path>). 738 */ 739 pos = ELFDEFNNAME(NO_ADDR); 740 if (epp->ep_esch->u.elf_probe_func) { 741 vaddr_t startp = (vaddr_t)pos; 742 743 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 744 &startp); 745 if (error) { 746 VOP_UNLOCK(epp->ep_vp); 747 goto bad; 748 } 749 pos = (Elf_Addr)startp; 750 } 751 752 if (is_dyn && (error = elf_placedynexec(epp, eh, ph)) != 0) { 753 VOP_UNLOCK(epp->ep_vp); 754 goto bad; 755 } 756 757 /* 758 * Load all the necessary sections 759 */ 760 for (i = 0; i < eh->e_phnum; i++) { 761 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 762 u_long size = 0; 763 764 switch (ph[i].p_type) { 765 case PT_LOAD: 766 if ((error = elf_load_psection(&epp->ep_vmcmds, 767 epp->ep_vp, &ph[i], &addr, &size, VMCMD_FIXED)) 768 != 0) { 769 VOP_UNLOCK(epp->ep_vp); 770 goto bad; 771 } 772 773 /* 774 * Consider this as text segment, if it is executable. 775 * If there is more than one text segment, pick the 776 * largest. 777 */ 778 if (ph[i].p_flags & PF_X) { 779 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 780 size > epp->ep_tsize) { 781 epp->ep_taddr = addr; 782 epp->ep_tsize = size; 783 } 784 end_text = addr + size; 785 } else { 786 epp->ep_daddr = addr; 787 epp->ep_dsize = size; 788 } 789 if (ph[i].p_offset == 0) { 790 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 791 } 792 break; 793 794 case PT_SHLIB: 795 /* SCO has these sections. */ 796 case PT_INTERP: 797 /* Already did this one. */ 798 case PT_DYNAMIC: 799 case PT_NOTE: 800 break; 801 case PT_PHDR: 802 /* Note address of program headers (in text segment) */ 803 phdr = ph[i].p_vaddr; 804 break; 805 806 default: 807 /* 808 * Not fatal; we don't need to understand everything. 809 */ 810 break; 811 } 812 } 813 814 /* Now done with the vnode. */ 815 VOP_UNLOCK(epp->ep_vp); 816 817 if (epp->ep_vmcmds.evs_used == 0) { 818 /* No VMCMD; there was no PT_LOAD section, or those 819 * sections were empty */ 820 DPRINTF("no vmcommands"); 821 error = ENOEXEC; 822 goto bad; 823 } 824 825 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 826 epp->ep_daddr = round_page(end_text); 827 epp->ep_dsize = 0; 828 } 829 830 /* 831 * Check if we found a dynamically linked binary and arrange to load 832 * its interpreter 833 */ 834 if (interp) { 835 u_int nused = epp->ep_vmcmds.evs_used; 836 u_long interp_offset = 0; 837 838 if ((error = elf_load_interp(l, epp, interp, 839 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { 840 goto bad; 841 } 842 if (epp->ep_vmcmds.evs_used == nused) { 843 /* elf_load_interp() has not set up any new VMCMD */ 844 DPRINTF("no vmcommands for interpreter"); 845 error = ENOEXEC; 846 goto bad; 847 } 848 849 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 850 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; 851 epp->ep_entryoffset = interp_offset; 852 epp->ep_entry = ap->arg_interp + interp_offset; 853 PNBUF_PUT(interp); 854 interp = NULL; 855 } else { 856 epp->ep_entry = eh->e_entry; 857 if (epp->ep_flags & EXEC_FORCEAUX) { 858 ap = kmem_zalloc(sizeof(*ap), KM_SLEEP); 859 ap->arg_interp = (vaddr_t)NULL; 860 } else { 861 ap = NULL; 862 } 863 } 864 865 if (ap) { 866 ap->arg_phaddr = phdr ? phdr : computed_phdr; 867 ap->arg_phentsize = eh->e_phentsize; 868 ap->arg_phnum = eh->e_phnum; 869 ap->arg_entry = eh->e_entry; 870 epp->ep_emul_arg = ap; 871 epp->ep_emul_arg_free = elf_free_emul_arg; 872 } 873 874 #ifdef ELF_MAP_PAGE_ZERO 875 /* Dell SVR4 maps page zero, yeuch! */ 876 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 877 epp->ep_vp, 0, VM_PROT_READ); 878 #endif 879 880 error = (*epp->ep_esch->es_setup_stack)(l, epp); 881 if (error) 882 goto bad; 883 884 kmem_free(ph, phsize); 885 return 0; 886 887 bad: 888 if (interp) 889 PNBUF_PUT(interp); 890 exec_free_emul_arg(epp); 891 kmem_free(ph, phsize); 892 kill_vmcmds(&epp->ep_vmcmds); 893 return error; 894 } 895 896 int 897 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 898 Elf_Ehdr *eh) 899 { 900 size_t i; 901 Elf_Phdr *ph; 902 size_t phsize; 903 char *nbuf; 904 int error; 905 int isnetbsd = 0; 906 907 epp->ep_pax_flags = 0; 908 909 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) { 910 DPRINTF("no signature %#x", eh->e_phnum); 911 return ENOEXEC; 912 } 913 914 phsize = eh->e_phnum * sizeof(Elf_Phdr); 915 ph = kmem_alloc(phsize, KM_SLEEP); 916 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 917 IO_NODELOCKED); 918 if (error) 919 goto out; 920 921 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); 922 for (i = 0; i < eh->e_phnum; i++) { 923 const char *nptr; 924 size_t nlen; 925 926 if (ph[i].p_type != PT_NOTE || 927 ph[i].p_filesz > ELF_MAXNOTESIZE) 928 continue; 929 930 nlen = ph[i].p_filesz; 931 error = exec_read(l, epp->ep_vp, ph[i].p_offset, nbuf, nlen, 932 IO_NODELOCKED); 933 if (error) 934 continue; 935 936 nptr = nbuf; 937 while (nlen > 0) { 938 const Elf_Nhdr *np; 939 const char *ndata, *ndesc; 940 941 /* note header */ 942 np = (const Elf_Nhdr *)nptr; 943 if (nlen < sizeof(*np)) { 944 break; 945 } 946 nptr += sizeof(*np); 947 nlen -= sizeof(*np); 948 949 /* note name */ 950 ndata = nptr; 951 if (nlen < roundup(np->n_namesz, 4)) { 952 break; 953 } 954 nptr += roundup(np->n_namesz, 4); 955 nlen -= roundup(np->n_namesz, 4); 956 957 /* note description */ 958 ndesc = nptr; 959 if (nlen < roundup(np->n_descsz, 4)) { 960 break; 961 } 962 nptr += roundup(np->n_descsz, 4); 963 nlen -= roundup(np->n_descsz, 4); 964 965 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc); 966 } 967 } 968 kmem_free(nbuf, ELF_MAXNOTESIZE); 969 970 error = isnetbsd ? 0 : ENOEXEC; 971 #ifdef DEBUG_ELF 972 if (error) 973 DPRINTF("not netbsd"); 974 #endif 975 out: 976 kmem_free(ph, phsize); 977 return error; 978 } 979 980 int 981 netbsd_elf_note(struct exec_package *epp, 982 const Elf_Nhdr *np, const char *ndata, const char *ndesc) 983 { 984 int isnetbsd = 0; 985 986 #ifdef DIAGNOSTIC 987 const char *badnote; 988 #define BADNOTE(n) badnote = (n) 989 #else 990 #define BADNOTE(n) 991 #endif 992 993 switch (np->n_type) { 994 case ELF_NOTE_TYPE_NETBSD_TAG: 995 /* It is us */ 996 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && 997 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && 998 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 999 ELF_NOTE_NETBSD_NAMESZ) == 0) { 1000 memcpy(&epp->ep_osversion, ndesc, 1001 ELF_NOTE_NETBSD_DESCSZ); 1002 isnetbsd = 1; 1003 break; 1004 } 1005 1006 /* 1007 * Ignore SuSE tags; SuSE's n_type is the same the 1008 * NetBSD one. 1009 */ 1010 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && 1011 memcmp(ndata, ELF_NOTE_SUSE_NAME, 1012 ELF_NOTE_SUSE_NAMESZ) == 0) 1013 break; 1014 /* 1015 * Ignore old GCC 1016 */ 1017 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && 1018 memcmp(ndata, ELF_NOTE_OGCC_NAME, 1019 ELF_NOTE_OGCC_NAMESZ) == 0) 1020 break; 1021 BADNOTE("NetBSD tag"); 1022 goto bad; 1023 1024 case ELF_NOTE_TYPE_PAX_TAG: 1025 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && 1026 np->n_descsz == ELF_NOTE_PAX_DESCSZ && 1027 memcmp(ndata, ELF_NOTE_PAX_NAME, 1028 ELF_NOTE_PAX_NAMESZ) == 0) { 1029 uint32_t flags; 1030 memcpy(&flags, ndesc, sizeof(flags)); 1031 /* Convert the flags and insert them into 1032 * the exec package. */ 1033 pax_setup_elf_flags(epp, flags); 1034 break; 1035 } 1036 BADNOTE("PaX tag"); 1037 goto bad; 1038 1039 case ELF_NOTE_TYPE_MARCH_TAG: 1040 /* Copy the machine arch into the package. */ 1041 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ 1042 && memcmp(ndata, ELF_NOTE_MARCH_NAME, 1043 ELF_NOTE_MARCH_NAMESZ) == 0) { 1044 /* Do not truncate the buffer */ 1045 if (np->n_descsz > sizeof(epp->ep_machine_arch)) { 1046 BADNOTE("description size limit"); 1047 goto bad; 1048 } 1049 /* 1050 * Ensure ndesc is NUL-terminated and of the 1051 * expected length. 1052 */ 1053 if (strnlen(ndesc, np->n_descsz) + 1 != 1054 np->n_descsz) { 1055 BADNOTE("description size"); 1056 goto bad; 1057 } 1058 strlcpy(epp->ep_machine_arch, ndesc, 1059 sizeof(epp->ep_machine_arch)); 1060 break; 1061 } 1062 BADNOTE("march tag"); 1063 goto bad; 1064 1065 case ELF_NOTE_TYPE_MCMODEL_TAG: 1066 /* arch specific check for code model */ 1067 #ifdef ELF_MD_MCMODEL_CHECK 1068 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ 1069 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, 1070 ELF_NOTE_MCMODEL_NAMESZ) == 0) { 1071 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); 1072 break; 1073 } 1074 BADNOTE("mcmodel tag"); 1075 goto bad; 1076 #endif 1077 break; 1078 1079 case ELF_NOTE_TYPE_SUSE_VERSION_TAG: 1080 break; 1081 1082 case ELF_NOTE_TYPE_GO_BUILDID_TAG: 1083 break; 1084 1085 case ELF_NOTE_TYPE_FDO_PACKAGING_METADATA: 1086 break; 1087 1088 case ELF_NOTE_TYPE_NETBSD_EMUL_TAG: 1089 /* Ancient NetBSD version tag */ 1090 break; 1091 1092 default: 1093 BADNOTE("unknown tag"); 1094 bad: 1095 #ifdef DIAGNOSTIC 1096 /* Ignore GNU tags */ 1097 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 1098 memcmp(ndata, ELF_NOTE_GNU_NAME, 1099 ELF_NOTE_GNU_NAMESZ) == 0) 1100 break; 1101 1102 int ns = (int)np->n_namesz; 1103 printf("%s: Unknown elf note type %d (%s): " 1104 "[namesz=%d, descsz=%d name=%-*.*s]\n", 1105 epp->ep_kname, np->n_type, badnote, np->n_namesz, 1106 np->n_descsz, ns, ns, ndata); 1107 #endif 1108 break; 1109 } 1110 1111 return isnetbsd; 1112 } 1113 1114 int 1115 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 1116 vaddr_t *pos) 1117 { 1118 int error; 1119 1120 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 1121 return error; 1122 #ifdef ELF_MD_PROBE_FUNC 1123 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 1124 return error; 1125 #elif defined(ELF_INTERP_NON_RELOCATABLE) 1126 *pos = ELF_LINK_ADDR; 1127 #endif 1128 epp->ep_flags |= EXEC_FORCEAUX; 1129 return 0; 1130 } 1131 1132 void 1133 elf_free_emul_arg(void *arg) 1134 { 1135 struct elf_args *ap = arg; 1136 KASSERT(ap != NULL); 1137 kmem_free(ap, sizeof(*ap)); 1138 }
Cache object: 00cc41b24f5f698d978f8050ed16810d
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