1 /* $NetBSD: exec_elf.c,v 1.107 2024/12/06 16:19:41 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 1.107 2024/12/06 16:19:41 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/types.h> 68 69 #include <sys/bitops.h> 70 #include <sys/cpu.h> 71 #include <sys/exec.h> 72 #include <sys/exec_elf.h> 73 #include <sys/kauth.h> 74 #include <sys/kmem.h> 75 #include <sys/mount.h> 76 #include <sys/namei.h> 77 #include <sys/pax.h> 78 #include <sys/proc.h> 79 #include <sys/sdt.h> 80 #include <sys/signalvar.h> 81 #include <sys/stat.h> 82 #include <sys/syscall.h> 83 #include <sys/vnode.h> 84 85 #include <machine/reg.h> 86 87 #include <compat/common/compat_util.h> 88 89 #include <uvm/uvm_param.h> 90 91 #define elf_check_header ELFNAME(check_header) 92 #define elf_copyargs ELFNAME(copyargs) 93 #define elf_populate_auxv ELFNAME(populate_auxv) 94 #define elf_load_interp ELFNAME(load_interp) 95 #define elf_load_psection ELFNAME(load_psection) 96 #define exec_elf_makecmds ELFNAME2(exec,makecmds) 97 #define netbsd_elf_signature ELFNAME2(netbsd,signature) 98 #define netbsd_elf_note ELFNAME2(netbsd,note) 99 #define netbsd_elf_probe ELFNAME2(netbsd,probe) 100 #define coredump ELFNAMEEND(coredump) 101 #define elf_free_emul_arg ELFNAME(free_emul_arg) 102 103 static int 104 elf_load_interp(struct lwp *, struct exec_package *, char *, 105 struct exec_vmcmd_set *, u_long *, Elf_Addr *); 106 static int 107 elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, 108 Elf_Addr *, u_long *, int); 109 110 int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *); 111 int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *, 112 const char *); 113 int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *, 114 vaddr_t *); 115 116 static void elf_free_emul_arg(void *); 117 118 #ifdef DEBUG_ELF 119 #define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__) 120 #else 121 #define DPRINTF(a, ...) 122 #endif 123 124 /* round up and down to page boundaries. */ 125 #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) 126 #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) 127 128 static int 129 elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph) 130 { 131 Elf_Addr align, offset; 132 int i; 133 134 for (align = 1, i = 0; i < eh->e_phnum; i++) 135 if (ph[i].p_type == PT_LOAD && ph[i].p_align > align) 136 align = ph[i].p_align; 137 138 offset = (Elf_Addr)pax_aslr_exec_offset(epp, align); 139 if (offset < epp->ep_vm_minaddr) 140 offset = roundup(epp->ep_vm_minaddr, align); 141 if ((offset & (align - 1)) != 0) { 142 DPRINTF("bad offset=%#jx align=%#jx", 143 (uintmax_t)offset, (uintmax_t)align); 144 return SET_ERROR(EINVAL); 145 } 146 147 for (i = 0; i < eh->e_phnum; i++) 148 ph[i].p_vaddr += offset; 149 epp->ep_entryoffset = offset; 150 eh->e_entry += offset; 151 return 0; 152 } 153 154 155 int 156 elf_populate_auxv(struct lwp *l, struct exec_package *pack, char **stackp) 157 { 158 size_t len, vlen; 159 AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname; 160 struct elf_args *ap; 161 char *path = l->l_proc->p_path; 162 int error; 163 164 execname = NULL; 165 a = ai; 166 167 memset(ai, 0, sizeof(ai)); 168 169 /* 170 * Push extra arguments on the stack needed by dynamically 171 * linked binaries 172 */ 173 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 174 struct vattr *vap = pack->ep_vap; 175 176 a->a_type = AT_PHDR; 177 a->a_v = ap->arg_phaddr; 178 a++; 179 180 a->a_type = AT_PHENT; 181 a->a_v = ap->arg_phentsize; 182 a++; 183 184 a->a_type = AT_PHNUM; 185 a->a_v = ap->arg_phnum; 186 a++; 187 188 a->a_type = AT_PAGESZ; 189 a->a_v = PAGE_SIZE; 190 a++; 191 192 a->a_type = AT_BASE; 193 a->a_v = ap->arg_interp; 194 a++; 195 196 a->a_type = AT_FLAGS; 197 a->a_v = 0; 198 a++; 199 200 a->a_type = AT_ENTRY; 201 a->a_v = ap->arg_entry; 202 a++; 203 204 a->a_type = AT_STACKBASE; 205 a->a_v = l->l_proc->p_stackbase; 206 a++; 207 208 a->a_type = AT_EUID; 209 if (vap->va_mode & S_ISUID) 210 a->a_v = vap->va_uid; 211 else 212 a->a_v = kauth_cred_geteuid(l->l_cred); 213 a++; 214 215 a->a_type = AT_RUID; 216 a->a_v = kauth_cred_getuid(l->l_cred); 217 a++; 218 219 a->a_type = AT_EGID; 220 if (vap->va_mode & S_ISGID) 221 a->a_v = vap->va_gid; 222 else 223 a->a_v = kauth_cred_getegid(l->l_cred); 224 a++; 225 226 a->a_type = AT_RGID; 227 a->a_v = kauth_cred_getgid(l->l_cred); 228 a++; 229 230 /* "/" means fexecve(2) could not resolve the pathname */ 231 if (path[0] == '/' && path[1] != '\0') { 232 execname = a; 233 a->a_type = AT_SUN_EXECNAME; 234 a++; 235 } 236 237 exec_free_emul_arg(pack); 238 } 239 240 a->a_type = AT_NULL; 241 a->a_v = 0; 242 a++; 243 244 vlen = (a - ai) * sizeof(ai[0]); 245 246 KASSERT(vlen <= sizeof(ai)); 247 248 if (execname) { 249 execname->a_v = (uintptr_t)(*stackp + vlen); 250 len = strlen(path) + 1; 251 if ((error = copyout(path, (*stackp + vlen), len)) != 0) 252 return error; 253 len = ALIGN(len); 254 } else { 255 len = 0; 256 } 257 258 if ((error = copyout(ai, *stackp, vlen)) != 0) 259 return error; 260 *stackp += vlen + len; 261 262 return 0; 263 } 264 265 /* 266 * Copy arguments onto the stack in the normal way, but add some 267 * extra information in case of dynamic binding. 268 */ 269 int 270 elf_copyargs(struct lwp *l, struct exec_package *pack, 271 struct ps_strings *arginfo, char **stackp, void *argp) 272 { 273 int error; 274 275 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 276 return error; 277 278 return elf_populate_auxv(l, pack, stackp); 279 } 280 281 /* 282 * elf_check_header(): 283 * 284 * Check header for validity; return 0 if ok, ENOEXEC if error 285 */ 286 int 287 elf_check_header(Elf_Ehdr *eh) 288 { 289 290 if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || 291 eh->e_ident[EI_CLASS] != ELFCLASS) { 292 DPRINTF("bad magic e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, " 293 "e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0], 294 eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2], 295 eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]); 296 return SET_ERROR(ENOEXEC); 297 } 298 299 switch (eh->e_machine) { 300 301 ELFDEFNNAME(MACHDEP_ID_CASES) 302 303 default: 304 DPRINTF("bad machine %#x", eh->e_machine); 305 return SET_ERROR(ENOEXEC); 306 } 307 308 if (ELF_EHDR_FLAGS_OK(eh) == 0) { 309 DPRINTF("bad flags %#x", eh->e_flags); 310 return SET_ERROR(ENOEXEC); 311 } 312 313 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) { 314 DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum); 315 return SET_ERROR(ENOEXEC); 316 } 317 318 return 0; 319 } 320 321 /* 322 * elf_load_psection(): 323 * 324 * Load a psection at the appropriate address 325 */ 326 static int 327 elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, 328 const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags) 329 { 330 u_long msize, psize, rm, rf; 331 long diff, offset; 332 int vmprot = 0; 333 334 KASSERT(VOP_ISLOCKED(vp) != LK_NONE); 335 336 /* 337 * If the user specified an address, then we load there. 338 */ 339 if (*addr == ELFDEFNNAME(NO_ADDR)) 340 *addr = ph->p_vaddr; 341 342 if (ph->p_align > 1) { 343 /* 344 * Make sure we are virtually aligned as we are supposed to be. 345 */ 346 diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); 347 if (*addr - diff != ELF_TRUNC(*addr, ph->p_align)) { 348 DPRINTF("bad alignment %#jx != %#jx\n", 349 (uintptr_t)(*addr - diff), 350 (uintptr_t)ELF_TRUNC(*addr, ph->p_align)); 351 return SET_ERROR(EINVAL); 352 } 353 /* 354 * But make sure to not map any pages before the start of the 355 * psection by limiting the difference to within a page. 356 */ 357 diff &= PAGE_MASK; 358 } else 359 diff = 0; 360 361 vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; 362 vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; 363 vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; 364 365 /* 366 * Adjust everything so it all starts on a page boundary. 367 */ 368 *addr -= diff; 369 offset = ph->p_offset - diff; 370 *size = ph->p_filesz + diff; 371 msize = ph->p_memsz + diff; 372 373 if (ph->p_align >= PAGE_SIZE) { 374 if ((ph->p_flags & PF_W) != 0) { 375 /* 376 * Because the pagedvn pager can't handle zero fill 377 * of the last data page if it's not page aligned we 378 * map the last page readvn. 379 */ 380 psize = trunc_page(*size); 381 } else { 382 psize = round_page(*size); 383 } 384 } else { 385 psize = *size; 386 } 387 388 if (psize > 0) { 389 NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? 390 vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, 391 offset, vmprot, flags); 392 flags &= VMCMD_RELATIVE; 393 } 394 if (psize < *size) { 395 NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, 396 *addr + psize, vp, offset + psize, vmprot, flags); 397 } 398 399 /* 400 * Check if we need to extend the size of the segment (does 401 * bss extend page the next page boundary)? 402 */ 403 rm = round_page(*addr + msize); 404 rf = round_page(*addr + *size); 405 406 if (rm != rf) { 407 NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 408 0, vmprot, flags & VMCMD_RELATIVE); 409 *size = msize; 410 } 411 return 0; 412 } 413 414 /* 415 * elf_load_interp(): 416 * 417 * Load an interpreter pointed to by path. 418 */ 419 static int 420 elf_load_interp(struct lwp *l, struct exec_package *epp, char *path, 421 struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last) 422 { 423 int error, i; 424 struct vnode *vp; 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_SHARED | 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 = SET_ERROR(EACCES); 467 goto bad; 468 } 469 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 470 goto bad; 471 472 /* 473 * Check mount point. Though we're not trying to exec this binary, 474 * we will be executing code from it, so if the mount point 475 * disallows execution or set-id-ness, we punt or kill the set-id. 476 */ 477 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 478 error = SET_ERROR(EACCES); 479 goto bad; 480 } 481 if (vp->v_mount->mnt_flag & MNT_NOSUID) 482 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 483 484 error = vn_marktext(vp); 485 if (error) 486 goto bad; 487 488 error = exec_read(l, vp, 0, &eh, sizeof(eh), IO_NODELOCKED); 489 if (error != 0) 490 goto bad; 491 492 if ((error = elf_check_header(&eh)) != 0) 493 goto bad; 494 if (eh.e_type != ET_DYN || eh.e_phnum == 0) { 495 DPRINTF("bad interpreter type %#x", eh.e_type); 496 error = SET_ERROR(ENOEXEC); 497 goto bad; 498 } 499 500 phsize = eh.e_phnum * sizeof(Elf_Phdr); 501 ph = kmem_alloc(phsize, KM_SLEEP); 502 503 error = exec_read(l, vp, eh.e_phoff, ph, phsize, IO_NODELOCKED); 504 if (error != 0) 505 goto bad; 506 507 #ifdef ELF_INTERP_NON_RELOCATABLE 508 /* 509 * Evil hack: Only MIPS should be non-relocatable, and the 510 * psections should have a high address (typically 0x5ffe0000). 511 * If it's now relocatable, it should be linked at 0 and the 512 * psections should have zeros in the upper part of the address. 513 * Otherwise, force the load at the linked address. 514 */ 515 if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0) 516 *last = ELFDEFNNAME(NO_ADDR); 517 #endif 518 519 /* 520 * If no position to load the interpreter was set by a probe 521 * function, pick the same address that a non-fixed mmap(0, ..) 522 * would (i.e. something safely out of the way). 523 */ 524 if (*last == ELFDEFNNAME(NO_ADDR)) { 525 u_long limit = 0; 526 /* 527 * Find the start and ending addresses of the psections to 528 * be loaded. This will give us the size. 529 */ 530 for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) { 531 if (ph[i].p_type == PT_LOAD) { 532 u_long psize = ph[i].p_vaddr + ph[i].p_memsz; 533 if (base_ph == NULL) 534 base_ph = &ph[i]; 535 if (psize > limit) 536 limit = psize; 537 } 538 } 539 540 if (base_ph == NULL) { 541 DPRINTF("no interpreter loadable sections"); 542 error = SET_ERROR(ENOEXEC); 543 goto bad; 544 } 545 546 /* 547 * Now compute the size and load address. 548 */ 549 addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, 550 epp->ep_daddr, 551 round_page(limit) - trunc_page(base_ph->p_vaddr), 552 use_topdown); 553 addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align, 554 use_topdown); 555 } else { 556 addr = *last; /* may be ELF_LINK_ADDR */ 557 } 558 559 /* 560 * Load all the necessary sections 561 */ 562 for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) { 563 switch (ph[i].p_type) { 564 case PT_LOAD: { 565 u_long size; 566 int flags; 567 568 if (base_ph == NULL) { 569 /* 570 * First encountered psection is always the 571 * base psection. Make sure it's aligned 572 * properly (align down for topdown and align 573 * upwards for not topdown). 574 */ 575 base_ph = &ph[i]; 576 flags = VMCMD_BASE; 577 if (addr == ELF_LINK_ADDR) 578 addr = ph[i].p_vaddr; 579 if (use_topdown) 580 addr = ELF_TRUNC(addr, ph[i].p_align); 581 else 582 addr = ELF_ROUND(addr, ph[i].p_align); 583 } else { 584 u_long limit = round_page(last_ph->p_vaddr 585 + last_ph->p_memsz); 586 u_long base = trunc_page(ph[i].p_vaddr); 587 588 /* 589 * If there is a gap in between the psections, 590 * map it as inaccessible so nothing else 591 * mmap'ed will be placed there. 592 */ 593 if (limit != base) { 594 NEW_VMCMD2(vcset, vmcmd_map_zero, 595 base - limit, 596 limit - base_ph->p_vaddr, NULLVP, 597 0, VM_PROT_NONE, VMCMD_RELATIVE); 598 } 599 600 addr = ph[i].p_vaddr - base_ph->p_vaddr; 601 flags = VMCMD_RELATIVE; 602 } 603 last_ph = &ph[i]; 604 if ((error = elf_load_psection(vcset, vp, &ph[i], &addr, 605 &size, flags)) != 0) 606 goto bad; 607 /* 608 * If entry is within this psection then this 609 * must contain the .text section. *entryoff is 610 * relative to the base psection. 611 */ 612 if (eh.e_entry >= ph[i].p_vaddr && 613 eh.e_entry < (ph[i].p_vaddr + size)) { 614 *entryoff = eh.e_entry - base_ph->p_vaddr; 615 } 616 addr += size; 617 break; 618 } 619 620 default: 621 break; 622 } 623 } 624 625 kmem_free(ph, phsize); 626 /* 627 * This value is ignored if TOPDOWN. 628 */ 629 *last = addr; 630 vput(vp); 631 return 0; 632 633 bad: 634 if (ph != NULL) 635 kmem_free(ph, phsize); 636 vput(vp); 637 return error; 638 } 639 640 /* 641 * exec_elf_makecmds(): Prepare an Elf binary's exec package 642 * 643 * First, set of the various offsets/lengths in the exec package. 644 * 645 * Then, mark the text image busy (so it can be demand paged) or error 646 * out if this is not possible. Finally, set up vmcmds for the 647 * text, data, bss, and stack segments. 648 */ 649 int 650 exec_elf_makecmds(struct lwp *l, struct exec_package *epp) 651 { 652 Elf_Ehdr *eh = epp->ep_hdr; 653 Elf_Phdr *ph, *pp; 654 Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0; 655 int error, i; 656 char *interp = NULL; 657 u_long phsize; 658 struct elf_args *ap; 659 bool is_dyn = false; 660 661 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) { 662 DPRINTF("small header %#x", epp->ep_hdrvalid); 663 return SET_ERROR(ENOEXEC); 664 } 665 if ((error = elf_check_header(eh)) != 0) 666 return error; 667 668 if (eh->e_type == ET_DYN) 669 /* PIE, and some libs have an entry point */ 670 is_dyn = true; 671 else if (eh->e_type != ET_EXEC) { 672 DPRINTF("bad type %#x", eh->e_type); 673 return SET_ERROR(ENOEXEC); 674 } 675 676 if (eh->e_phnum == 0) { 677 DPRINTF("no program headers"); 678 return SET_ERROR(ENOEXEC); 679 } 680 681 /* XXX only LK_EXCLUSIVE to match all others - allow spinning */ 682 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 683 error = vn_marktext(epp->ep_vp); 684 if (error) { 685 VOP_UNLOCK(epp->ep_vp); 686 return error; 687 } 688 689 /* 690 * Allocate space to hold all the program headers, and read them 691 * from the file 692 */ 693 phsize = eh->e_phnum * sizeof(Elf_Phdr); 694 ph = kmem_alloc(phsize, KM_SLEEP); 695 696 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 697 IO_NODELOCKED); 698 if (error != 0) { 699 VOP_UNLOCK(epp->ep_vp); 700 goto bad; 701 } 702 703 epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 704 epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 705 706 for (i = 0; i < eh->e_phnum; i++) { 707 pp = &ph[i]; 708 if (pp->p_type == PT_INTERP) { 709 if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) { 710 DPRINTF("bad interpreter namelen %#jx", 711 (uintmax_t)pp->p_filesz); 712 error = SET_ERROR(ENOEXEC); 713 VOP_UNLOCK(epp->ep_vp); 714 goto bad; 715 } 716 interp = PNBUF_GET(); 717 error = exec_read(l, epp->ep_vp, pp->p_offset, interp, 718 pp->p_filesz, IO_NODELOCKED); 719 if (error != 0) { 720 VOP_UNLOCK(epp->ep_vp); 721 goto bad; 722 } 723 /* Ensure interp is NUL-terminated and of the expected length */ 724 if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) { 725 DPRINTF("bad interpreter name"); 726 error = SET_ERROR(ENOEXEC); 727 VOP_UNLOCK(epp->ep_vp); 728 goto bad; 729 } 730 break; 731 } 732 } 733 734 /* 735 * On the same architecture, we may be emulating different systems. 736 * See which one will accept this executable. 737 * 738 * Probe functions would normally see if the interpreter (if any) 739 * exists. Emulation packages may possibly replace the interpreter in 740 * interp with a changed path (/emul/xxx/<path>). 741 */ 742 pos = ELFDEFNNAME(NO_ADDR); 743 if (epp->ep_esch->u.elf_probe_func) { 744 vaddr_t startp = (vaddr_t)pos; 745 746 error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp, 747 &startp); 748 if (error) { 749 VOP_UNLOCK(epp->ep_vp); 750 goto bad; 751 } 752 pos = (Elf_Addr)startp; 753 } 754 755 if (is_dyn && (error = elf_placedynexec(epp, eh, ph)) != 0) { 756 VOP_UNLOCK(epp->ep_vp); 757 goto bad; 758 } 759 760 /* 761 * Load all the necessary sections 762 */ 763 for (i = 0; i < eh->e_phnum; i++) { 764 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 765 u_long size = 0; 766 767 switch (ph[i].p_type) { 768 case PT_LOAD: 769 if ((error = elf_load_psection(&epp->ep_vmcmds, 770 epp->ep_vp, &ph[i], &addr, &size, VMCMD_FIXED)) 771 != 0) { 772 VOP_UNLOCK(epp->ep_vp); 773 goto bad; 774 } 775 776 /* 777 * Consider this as text segment, if it is executable. 778 * If there is more than one text segment, pick the 779 * largest. 780 */ 781 if (ph[i].p_flags & PF_X) { 782 if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) || 783 size > epp->ep_tsize) { 784 epp->ep_taddr = addr; 785 epp->ep_tsize = size; 786 } 787 end_text = addr + size; 788 } else { 789 epp->ep_daddr = addr; 790 epp->ep_dsize = size; 791 } 792 if (ph[i].p_offset == 0) { 793 computed_phdr = ph[i].p_vaddr + eh->e_phoff; 794 } 795 break; 796 797 case PT_SHLIB: 798 /* SCO has these sections. */ 799 case PT_INTERP: 800 /* Already did this one. */ 801 case PT_DYNAMIC: 802 case PT_NOTE: 803 break; 804 case PT_PHDR: 805 /* Note address of program headers (in text segment) */ 806 phdr = ph[i].p_vaddr; 807 break; 808 809 default: 810 /* 811 * Not fatal; we don't need to understand everything. 812 */ 813 break; 814 } 815 } 816 817 /* Now done with the vnode. */ 818 VOP_UNLOCK(epp->ep_vp); 819 820 if (epp->ep_vmcmds.evs_used == 0) { 821 /* No VMCMD; there was no PT_LOAD section, or those 822 * sections were empty */ 823 DPRINTF("no vmcommands"); 824 error = SET_ERROR(ENOEXEC); 825 goto bad; 826 } 827 828 if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { 829 epp->ep_daddr = round_page(end_text); 830 epp->ep_dsize = 0; 831 } 832 833 /* 834 * Check if we found a dynamically linked binary and arrange to load 835 * its interpreter 836 */ 837 if (interp) { 838 u_int nused = epp->ep_vmcmds.evs_used; 839 u_long interp_offset = 0; 840 841 if ((error = elf_load_interp(l, epp, interp, 842 &epp->ep_vmcmds, &interp_offset, &pos)) != 0) { 843 goto bad; 844 } 845 if (epp->ep_vmcmds.evs_used == nused) { 846 /* elf_load_interp() has not set up any new VMCMD */ 847 DPRINTF("no vmcommands for interpreter"); 848 error = SET_ERROR(ENOEXEC); 849 goto bad; 850 } 851 852 ap = kmem_alloc(sizeof(*ap), KM_SLEEP); 853 ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr; 854 epp->ep_entryoffset = interp_offset; 855 epp->ep_entry = ap->arg_interp + interp_offset; 856 PNBUF_PUT(interp); 857 interp = NULL; 858 } else { 859 epp->ep_entry = eh->e_entry; 860 if (epp->ep_flags & EXEC_FORCEAUX) { 861 ap = kmem_zalloc(sizeof(*ap), KM_SLEEP); 862 ap->arg_interp = (vaddr_t)NULL; 863 } else { 864 ap = NULL; 865 } 866 } 867 868 if (ap) { 869 ap->arg_phaddr = phdr ? phdr : computed_phdr; 870 ap->arg_phentsize = eh->e_phentsize; 871 ap->arg_phnum = eh->e_phnum; 872 ap->arg_entry = eh->e_entry; 873 epp->ep_emul_arg = ap; 874 epp->ep_emul_arg_free = elf_free_emul_arg; 875 } 876 877 #ifdef ELF_MAP_PAGE_ZERO 878 /* Dell SVR4 maps page zero, yeuch! */ 879 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0, 880 epp->ep_vp, 0, VM_PROT_READ); 881 #endif 882 883 error = (*epp->ep_esch->es_setup_stack)(l, epp); 884 if (error) 885 goto bad; 886 887 kmem_free(ph, phsize); 888 return 0; 889 890 bad: 891 if (interp) 892 PNBUF_PUT(interp); 893 exec_free_emul_arg(epp); 894 kmem_free(ph, phsize); 895 kill_vmcmds(&epp->ep_vmcmds); 896 return error; 897 } 898 899 int 900 netbsd_elf_signature(struct lwp *l, struct exec_package *epp, 901 Elf_Ehdr *eh) 902 { 903 size_t i; 904 Elf_Phdr *ph; 905 size_t phsize; 906 char *nbuf; 907 int error; 908 int isnetbsd = 0; 909 910 epp->ep_pax_flags = 0; 911 912 if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) { 913 DPRINTF("no signature %#x", eh->e_phnum); 914 return SET_ERROR(ENOEXEC); 915 } 916 917 phsize = eh->e_phnum * sizeof(Elf_Phdr); 918 ph = kmem_alloc(phsize, KM_SLEEP); 919 error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize, 920 IO_NODELOCKED); 921 if (error) 922 goto out; 923 924 nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP); 925 for (i = 0; i < eh->e_phnum; i++) { 926 const char *nptr; 927 size_t nlen; 928 929 if (ph[i].p_type != PT_NOTE || 930 ph[i].p_filesz > ELF_MAXNOTESIZE) 931 continue; 932 933 nlen = ph[i].p_filesz; 934 error = exec_read(l, epp->ep_vp, ph[i].p_offset, nbuf, nlen, 935 IO_NODELOCKED); 936 if (error) 937 continue; 938 939 nptr = nbuf; 940 while (nlen > 0) { 941 const Elf_Nhdr *np; 942 const char *ndata, *ndesc; 943 944 /* note header */ 945 np = (const Elf_Nhdr *)nptr; 946 if (nlen < sizeof(*np)) { 947 break; 948 } 949 nptr += sizeof(*np); 950 nlen -= sizeof(*np); 951 952 /* note name */ 953 ndata = nptr; 954 if (nlen < roundup(np->n_namesz, 4)) { 955 break; 956 } 957 nptr += roundup(np->n_namesz, 4); 958 nlen -= roundup(np->n_namesz, 4); 959 960 /* note description */ 961 ndesc = nptr; 962 if (nlen < roundup(np->n_descsz, 4)) { 963 break; 964 } 965 nptr += roundup(np->n_descsz, 4); 966 nlen -= roundup(np->n_descsz, 4); 967 968 isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc); 969 } 970 } 971 kmem_free(nbuf, ELF_MAXNOTESIZE); 972 973 error = isnetbsd ? 0 : SET_ERROR(ENOEXEC); 974 #ifdef DEBUG_ELF 975 if (error) 976 DPRINTF("not netbsd"); 977 #endif 978 out: 979 kmem_free(ph, phsize); 980 return error; 981 } 982 983 int 984 netbsd_elf_note(struct exec_package *epp, 985 const Elf_Nhdr *np, const char *ndata, const char *ndesc) 986 { 987 int isnetbsd = 0; 988 989 #ifdef DIAGNOSTIC 990 const char *badnote; 991 #define BADNOTE(n) badnote = (n) 992 #else 993 #define BADNOTE(n) 994 #endif 995 996 switch (np->n_type) { 997 case ELF_NOTE_TYPE_NETBSD_TAG: 998 /* It is us */ 999 if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ && 1000 np->n_descsz == ELF_NOTE_NETBSD_DESCSZ && 1001 memcmp(ndata, ELF_NOTE_NETBSD_NAME, 1002 ELF_NOTE_NETBSD_NAMESZ) == 0) { 1003 memcpy(&epp->ep_osversion, ndesc, 1004 ELF_NOTE_NETBSD_DESCSZ); 1005 isnetbsd = 1; 1006 break; 1007 } 1008 1009 /* 1010 * Ignore SuSE tags; SuSE's n_type is the same the 1011 * NetBSD one. 1012 */ 1013 if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ && 1014 memcmp(ndata, ELF_NOTE_SUSE_NAME, 1015 ELF_NOTE_SUSE_NAMESZ) == 0) 1016 break; 1017 /* 1018 * Ignore old GCC 1019 */ 1020 if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ && 1021 memcmp(ndata, ELF_NOTE_OGCC_NAME, 1022 ELF_NOTE_OGCC_NAMESZ) == 0) 1023 break; 1024 BADNOTE("NetBSD tag"); 1025 goto bad; 1026 1027 case ELF_NOTE_TYPE_PAX_TAG: 1028 if (np->n_namesz == ELF_NOTE_PAX_NAMESZ && 1029 np->n_descsz == ELF_NOTE_PAX_DESCSZ && 1030 memcmp(ndata, ELF_NOTE_PAX_NAME, 1031 ELF_NOTE_PAX_NAMESZ) == 0) { 1032 uint32_t flags; 1033 memcpy(&flags, ndesc, sizeof(flags)); 1034 /* Convert the flags and insert them into 1035 * the exec package. */ 1036 pax_setup_elf_flags(epp, flags); 1037 break; 1038 } 1039 BADNOTE("PaX tag"); 1040 goto bad; 1041 1042 case ELF_NOTE_TYPE_MARCH_TAG: 1043 /* Copy the machine arch into the package. */ 1044 if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ 1045 && memcmp(ndata, ELF_NOTE_MARCH_NAME, 1046 ELF_NOTE_MARCH_NAMESZ) == 0) { 1047 /* Do not truncate the buffer */ 1048 if (np->n_descsz > sizeof(epp->ep_machine_arch)) { 1049 BADNOTE("description size limit"); 1050 goto bad; 1051 } 1052 /* 1053 * Ensure ndesc is NUL-terminated and of the 1054 * expected length. 1055 */ 1056 if (strnlen(ndesc, np->n_descsz) + 1 != 1057 np->n_descsz) { 1058 BADNOTE("description size"); 1059 goto bad; 1060 } 1061 strlcpy(epp->ep_machine_arch, ndesc, 1062 sizeof(epp->ep_machine_arch)); 1063 break; 1064 } 1065 BADNOTE("march tag"); 1066 goto bad; 1067 1068 case ELF_NOTE_TYPE_MCMODEL_TAG: 1069 /* arch specific check for code model */ 1070 #ifdef ELF_MD_MCMODEL_CHECK 1071 if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ 1072 && memcmp(ndata, ELF_NOTE_MCMODEL_NAME, 1073 ELF_NOTE_MCMODEL_NAMESZ) == 0) { 1074 ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz); 1075 break; 1076 } 1077 BADNOTE("mcmodel tag"); 1078 goto bad; 1079 #endif 1080 break; 1081 1082 case ELF_NOTE_TYPE_SUSE_VERSION_TAG: 1083 break; 1084 1085 case ELF_NOTE_TYPE_GO_BUILDID_TAG: 1086 break; 1087 1088 case ELF_NOTE_TYPE_FDO_PACKAGING_METADATA: 1089 break; 1090 1091 case ELF_NOTE_TYPE_NETBSD_EMUL_TAG: 1092 /* Ancient NetBSD version tag */ 1093 break; 1094 1095 default: 1096 BADNOTE("unknown tag"); 1097 bad: 1098 #ifdef DIAGNOSTIC 1099 /* Ignore GNU tags */ 1100 if (np->n_namesz == ELF_NOTE_GNU_NAMESZ && 1101 memcmp(ndata, ELF_NOTE_GNU_NAME, 1102 ELF_NOTE_GNU_NAMESZ) == 0) 1103 break; 1104 1105 int ns = (int)np->n_namesz; 1106 printf("%s: Unknown elf note type %d (%s): " 1107 "[namesz=%d, descsz=%d name=%-*.*s]\n", 1108 epp->ep_kname, np->n_type, badnote, np->n_namesz, 1109 np->n_descsz, ns, ns, ndata); 1110 #endif 1111 break; 1112 } 1113 1114 return isnetbsd; 1115 } 1116 1117 int 1118 netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp, 1119 vaddr_t *pos) 1120 { 1121 int error; 1122 1123 if ((error = netbsd_elf_signature(l, epp, eh)) != 0) 1124 return error; 1125 #ifdef ELF_MD_PROBE_FUNC 1126 if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0) 1127 return error; 1128 #elif defined(ELF_INTERP_NON_RELOCATABLE) 1129 *pos = ELF_LINK_ADDR; 1130 #endif 1131 epp->ep_flags |= EXEC_FORCEAUX; 1132 return 0; 1133 } 1134 1135 void 1136 elf_free_emul_arg(void *arg) 1137 { 1138 struct elf_args *ap = arg; 1139 KASSERT(ap != NULL); 1140 kmem_free(ap, sizeof(*ap)); 1141 } 1142
Indexes created Sat Sep 20 22:09:52 GMT 2025