sys/kern/imgact_elf.c

   1 /*-
   2  * Copyright (c) 1995-1996 Søren Schmidt
   3  * Copyright (c) 1996 Peter Wemm
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer
  11  *    in this position and unchanged.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software withough specific prior written permission
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/kern/imgact_elf.c,v 1.73.2.13 2002/12/28 19:49:41 dillon Exp $
  30  * $DragonFly: src/sys/kern/imgact_elf.c,v 1.2 2003/06/17 04:28:41 dillon Exp $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/exec.h>
  35 #include <sys/fcntl.h>
  36 #include <sys/imgact.h>
  37 #include <sys/imgact_elf.h>
  38 #include <sys/kernel.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mman.h>
  41 #include <sys/namei.h>
  42 #include <sys/pioctl.h>
  43 #include <sys/proc.h>
  44 #include <sys/procfs.h>
  45 #include <sys/resourcevar.h>
  46 #include <sys/signalvar.h>
  47 #include <sys/stat.h>
  48 #include <sys/syscall.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/sysent.h>
  51 #include <sys/systm.h>
  52 #include <sys/vnode.h>
  53
  54 #include <vm/vm.h>
  55 #include <vm/vm_kern.h>
  56 #include <vm/vm_param.h>
  57 #include <vm/pmap.h>
  58 #include <sys/lock.h>
  59 #include <vm/vm_map.h>
  60 #include <vm/vm_object.h>
  61 #include <vm/vm_extern.h>
  62
  63 #include <machine/elf.h>
  64 #include <machine/md_var.h>
  65
  66 #define OLD_EI_BRAND    8
  67
  68 __ElfType(Brandinfo);
  69 __ElfType(Auxargs);
  70
  71 static int elf_check_header __P((const Elf_Ehdr *hdr));
  72 static int elf_freebsd_fixup __P((register_t **stack_base,
  73     struct image_params *imgp));
  74 static int elf_load_file __P((struct proc *p, const char *file, u_long *addr,
  75     u_long *entry));
  76 static int elf_load_section __P((struct proc *p,
  77     struct vmspace *vmspace, struct vnode *vp,
  78     vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz,
  79     vm_prot_t prot));
  80 static int exec_elf_imgact __P((struct image_params *imgp));
  81
  82 static int elf_trace = 0;
  83 SYSCTL_INT(_debug, OID_AUTO, elf_trace, CTLFLAG_RW, &elf_trace, 0, "");
  84 static int elf_legacy_coredump = 0;
  85 SYSCTL_INT(_debug, OID_AUTO, elf_legacy_coredump, CTLFLAG_RW,
  86     &elf_legacy_coredump, 0, "");
  87
  88 static struct sysentvec elf_freebsd_sysvec = {
  89         SYS_MAXSYSCALL,
  90         sysent,
  91         0,
  92         0,
  93         0,
  94         0,
  95         0,
  96         0,
  97         elf_freebsd_fixup,
  98         sendsig,
  99         sigcode,
 100         &szsigcode,
 101         0,
 102         "FreeBSD ELF",
 103         elf_coredump,
 104         NULL,
 105         MINSIGSTKSZ
 106 };
 107
 108 static Elf_Brandinfo freebsd_brand_info = {
 109                                                 ELFOSABI_FREEBSD,
 110                                                 "FreeBSD",
 111                                                 "",
 112                                                 "/usr/libexec/ld-elf.so.1",
 113                                                 &elf_freebsd_sysvec
 114                                           };
 115 static Elf_Brandinfo *elf_brand_list[MAX_BRANDS] = {
 116                                                         &freebsd_brand_info,
 117                                                         NULL, NULL, NULL,
 118                                                         NULL, NULL, NULL, NULL
 119                                                     };
 120
 121 int
 122 elf_insert_brand_entry(Elf_Brandinfo *entry)
 123 {
 124         int i;
 125
 126         for (i=1; i<MAX_BRANDS; i++) {
 127                 if (elf_brand_list[i] == NULL) {
 128                         elf_brand_list[i] = entry;
 129                         break;
 130                 }
 131         }
 132         if (i == MAX_BRANDS)
 133                 return -1;
 134         return 0;
 135 }
 136
 137 int
 138 elf_remove_brand_entry(Elf_Brandinfo *entry)
 139 {
 140         int i;
 141
 142         for (i=1; i<MAX_BRANDS; i++) {
 143                 if (elf_brand_list[i] == entry) {
 144                         elf_brand_list[i] = NULL;
 145                         break;
 146                 }
 147         }
 148         if (i == MAX_BRANDS)
 149                 return -1;
 150         return 0;
 151 }
 152
 153 int
 154 elf_brand_inuse(Elf_Brandinfo *entry)
 155 {
 156         struct proc *p;
 157         int rval = FALSE;
 158
 159         LIST_FOREACH(p, &allproc, p_list) {
 160                 if (p->p_sysent == entry->sysvec) {
 161                         rval = TRUE;
 162                         break;
 163                 }
 164         }
 165
 166         return (rval);
 167 }
 168
 169 static int
 170 elf_check_header(const Elf_Ehdr *hdr)
 171 {
 172         if (!IS_ELF(*hdr) ||
 173             hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 174             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 175             hdr->e_ident[EI_VERSION] != EV_CURRENT)
 176                 return ENOEXEC;
 177
 178         if (!ELF_MACHINE_OK(hdr->e_machine))
 179                 return ENOEXEC;
 180
 181         if (hdr->e_version != ELF_TARG_VER)
 182                 return ENOEXEC;
 183
 184         return 0;
 185 }
 186
 187 static int
 188 elf_load_section(struct proc *p, struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot)
 189 {
 190         size_t map_len;
 191         vm_offset_t map_addr;
 192         int error, rv, cow;
 193         size_t copy_len;
 194         vm_object_t object;
 195         vm_offset_t file_addr;
 196         vm_offset_t data_buf = 0;
 197
 198         VOP_GETVOBJECT(vp, &object);
 199         error = 0;
 200
 201         /*
 202          * It's necessary to fail if the filsz + offset taken from the
 203          * header is greater than the actual file pager object's size.
 204          * If we were to allow this, then the vm_map_find() below would
 205          * walk right off the end of the file object and into the ether.
 206          *
 207          * While I'm here, might as well check for something else that
 208          * is invalid: filsz cannot be greater than memsz.
 209          */
 210         if ((off_t)filsz + offset > object->un_pager.vnp.vnp_size ||
 211             filsz > memsz) {
 212                 uprintf("elf_load_section: truncated ELF file\n");
 213                 return (ENOEXEC);
 214         }
 215
 216         map_addr = trunc_page((vm_offset_t)vmaddr);
 217         file_addr = trunc_page(offset);
 218
 219         /*
 220          * We have two choices.  We can either clear the data in the last page
 221          * of an oversized mapping, or we can start the anon mapping a page
 222          * early and copy the initialized data into that first page.  We
 223          * choose the second..
 224          */
 225         if (memsz > filsz)
 226                 map_len = trunc_page(offset+filsz) - file_addr;
 227         else
 228                 map_len = round_page(offset+filsz) - file_addr;
 229
 230         if (map_len != 0) {
 231                 vm_object_reference(object);
 232
 233                 /* cow flags: don't dump readonly sections in core */
 234                 cow = MAP_COPY_ON_WRITE | MAP_PREFAULT |
 235                     (prot & VM_PROT_WRITE ? 0 : MAP_DISABLE_COREDUMP);
 236
 237                 vm_map_lock(&vmspace->vm_map);
 238                 rv = vm_map_insert(&vmspace->vm_map,
 239                                       object,
 240                                       file_addr,        /* file offset */
 241                                       map_addr,         /* virtual start */
 242                                       map_addr + map_len,/* virtual end */
 243                                       prot,
 244                                       VM_PROT_ALL,
 245                                       cow);
 246                 vm_map_unlock(&vmspace->vm_map);
 247                 if (rv != KERN_SUCCESS) {
 248                         vm_object_deallocate(object);
 249                         return EINVAL;
 250                 }
 251
 252                 /* we can stop now if we've covered it all */
 253                 if (memsz == filsz) {
 254                         return 0;
 255                 }
 256         }
 257
 258
 259         /*
 260          * We have to get the remaining bit of the file into the first part
 261          * of the oversized map segment.  This is normally because the .data
 262          * segment in the file is extended to provide bss.  It's a neat idea
 263          * to try and save a page, but it's a pain in the behind to implement.
 264          */
 265         copy_len = (offset + filsz) - trunc_page(offset + filsz);
 266         map_addr = trunc_page((vm_offset_t)vmaddr + filsz);
 267         map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr;
 268
 269         /* This had damn well better be true! */
 270         if (map_len != 0) {
 271                 vm_map_lock(&vmspace->vm_map);
 272                 rv = vm_map_insert(&vmspace->vm_map, NULL, 0,
 273                                         map_addr, map_addr + map_len,
 274                                         VM_PROT_ALL, VM_PROT_ALL, 0);
 275                 vm_map_unlock(&vmspace->vm_map);
 276                 if (rv != KERN_SUCCESS) {
 277                         return EINVAL;
 278                 }
 279         }
 280
 281         if (copy_len != 0) {
 282                 vm_object_reference(object);
 283                 rv = vm_map_find(exec_map,
 284                                  object,
 285                                  trunc_page(offset + filsz),
 286                                  &data_buf,
 287                                  PAGE_SIZE,
 288                                  TRUE,
 289                                  VM_PROT_READ,
 290                                  VM_PROT_ALL,
 291                                  MAP_COPY_ON_WRITE | MAP_PREFAULT_PARTIAL);
 292                 if (rv != KERN_SUCCESS) {
 293                         vm_object_deallocate(object);
 294                         return EINVAL;
 295                 }
 296
 297                 /* send the page fragment to user space */
 298                 error = copyout((caddr_t)data_buf, (caddr_t)map_addr, copy_len);
 299                 vm_map_remove(exec_map, data_buf, data_buf + PAGE_SIZE);
 300                 if (error) {
 301                         return (error);
 302                 }
 303         }
 304
 305         /*
 306          * set it to the specified protection
 307          */
 308         vm_map_protect(&vmspace->vm_map, map_addr, map_addr + map_len,  prot,
 309                        FALSE);
 310
 311         return error;
 312 }
 313
 314 /*
 315  * Load the file "file" into memory.  It may be either a shared object
 316  * or an executable.
 317  *
 318  * The "addr" reference parameter is in/out.  On entry, it specifies
 319  * the address where a shared object should be loaded.  If the file is
 320  * an executable, this value is ignored.  On exit, "addr" specifies
 321  * where the file was actually loaded.
 322  *
 323  * The "entry" reference parameter is out only.  On exit, it specifies
 324  * the entry point for the loaded file.
 325  */
 326 static int
 327 elf_load_file(struct proc *p, const char *file, u_long *addr, u_long *entry)
 328 {
 329         struct {
 330                 struct nameidata nd;
 331                 struct vattr attr;
 332                 struct image_params image_params;
 333         } *tempdata;
 334         const Elf_Ehdr *hdr = NULL;
 335         const Elf_Phdr *phdr = NULL;
 336         struct nameidata *nd;
 337         struct vmspace *vmspace = p->p_vmspace;
 338         struct vattr *attr;
 339         struct image_params *imgp;
 340         vm_prot_t prot;
 341         u_long rbase;
 342         u_long base_addr = 0;
 343         int error, i, numsegs;
 344
 345         tempdata = malloc(sizeof(*tempdata), M_TEMP, M_WAITOK);
 346         nd = &tempdata->nd;
 347         attr = &tempdata->attr;
 348         imgp = &tempdata->image_params;
 349
 350         /*
 351          * Initialize part of the common data
 352          */
 353         imgp->proc = p;
 354         imgp->uap = NULL;
 355         imgp->attr = attr;
 356         imgp->firstpage = NULL;
 357         imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
 358
 359         if (imgp->image_header == NULL) {
 360                 nd->ni_vp = NULL;
 361                 error = ENOMEM;
 362                 goto fail;
 363         }
 364
 365         NDINIT(nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, p);
 366
 367         if ((error = namei(nd)) != 0) {
 368                 nd->ni_vp = NULL;
 369                 goto fail;
 370         }
 371         NDFREE(nd, NDF_ONLY_PNBUF);
 372         imgp->vp = nd->ni_vp;
 373
 374         /*
 375          * Check permissions, modes, uid, etc on the file, and "open" it.
 376          */
 377         error = exec_check_permissions(imgp);
 378         if (error) {
 379                 VOP_UNLOCK(nd->ni_vp, 0, p);
 380                 goto fail;
 381         }
 382
 383         error = exec_map_first_page(imgp);
 384         /*
 385          * Also make certain that the interpreter stays the same, so set
 386          * its VTEXT flag, too.
 387          */
 388         if (error == 0)
 389                 nd->ni_vp->v_flag |= VTEXT;
 390         VOP_UNLOCK(nd->ni_vp, 0, p);
 391         if (error)
 392                 goto fail;
 393
 394         hdr = (const Elf_Ehdr *)imgp->image_header;
 395         if ((error = elf_check_header(hdr)) != 0)
 396                 goto fail;
 397         if (hdr->e_type == ET_DYN)
 398                 rbase = *addr;
 399         else if (hdr->e_type == ET_EXEC)
 400                 rbase = 0;
 401         else {
 402                 error = ENOEXEC;
 403                 goto fail;
 404         }
 405
 406         /* Only support headers that fit within first page for now */
 407         if ((hdr->e_phoff > PAGE_SIZE) ||
 408             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 409                 error = ENOEXEC;
 410                 goto fail;
 411         }
 412
 413         phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
 414
 415         for (i = 0, numsegs = 0; i < hdr->e_phnum; i++) {
 416                 if (phdr[i].p_type == PT_LOAD) {        /* Loadable segment */
 417                         prot = 0;
 418                         if (phdr[i].p_flags & PF_X)
 419                                 prot |= VM_PROT_EXECUTE;
 420                         if (phdr[i].p_flags & PF_W)
 421                                 prot |= VM_PROT_WRITE;
 422                         if (phdr[i].p_flags & PF_R)
 423                                 prot |= VM_PROT_READ;
 424
 425                         if ((error = elf_load_section(p, vmspace, nd->ni_vp,
 426                                                      phdr[i].p_offset,
 427                                                      (caddr_t)phdr[i].p_vaddr +
 428                                                         rbase,
 429                                                      phdr[i].p_memsz,
 430                                                      phdr[i].p_filesz, prot)) != 0)
 431                                 goto fail;
 432                         /*
 433                          * Establish the base address if this is the
 434                          * first segment.
 435                          */
 436                         if (numsegs == 0)
 437                                 base_addr = trunc_page(phdr[i].p_vaddr + rbase);
 438                         numsegs++;
 439                 }
 440         }
 441         *addr = base_addr;
 442         *entry=(unsigned long)hdr->e_entry + rbase;
 443
 444 fail:
 445         if (imgp->firstpage)
 446                 exec_unmap_first_page(imgp);
 447         if (imgp->image_header)
 448                 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
 449                         PAGE_SIZE);
 450         if (nd->ni_vp)
 451                 vrele(nd->ni_vp);
 452
 453         free(tempdata, M_TEMP);
 454
 455         return error;
 456 }
 457
 458 /*
 459  * non static, as it can be overridden by start_init()
 460  */
 461 int fallback_elf_brand = -1;
 462 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
 463                 &fallback_elf_brand, -1,
 464                 "ELF brand of last resort");
 465
 466 static int
 467 exec_elf_imgact(struct image_params *imgp)
 468 {
 469         const Elf_Ehdr *hdr = (const Elf_Ehdr *) imgp->image_header;
 470         const Elf_Phdr *phdr;
 471         Elf_Auxargs *elf_auxargs = NULL;
 472         struct vmspace *vmspace;
 473         vm_prot_t prot;
 474         u_long text_size = 0, data_size = 0, total_size = 0;
 475         u_long text_addr = 0, data_addr = 0;
 476         u_long seg_size, seg_addr;
 477         u_long addr, entry = 0, proghdr = 0;
 478         int error, i;
 479         const char *interp = NULL;
 480         Elf_Brandinfo *brand_info;
 481         char *path;
 482
 483         /*
 484          * Do we have a valid ELF header ?
 485          */
 486         if (elf_check_header(hdr) != 0 || hdr->e_type != ET_EXEC)
 487                 return -1;
 488
 489         /*
 490          * From here on down, we return an errno, not -1, as we've
 491          * detected an ELF file.
 492          */
 493
 494         if ((hdr->e_phoff > PAGE_SIZE) ||
 495             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 496                 /* Only support headers in first page for now */
 497                 return ENOEXEC;
 498         }
 499         phdr = (const Elf_Phdr*)(imgp->image_header + hdr->e_phoff);
 500
 501         /*
 502          * From this point on, we may have resources that need to be freed.
 503          */
 504
 505         if ((error = exec_extract_strings(imgp)) != 0)
 506                 goto fail;
 507
 508         exec_new_vmspace(imgp);
 509
 510         /*
 511          * Yeah, I'm paranoid.  There is every reason in the world to get
 512          * VTEXT now since from here on out, there are places we can have
 513          * a context switch.  Better safe than sorry; I really don't want
 514          * the file to change while it's being loaded.
 515          */
 516         simple_lock(&imgp->vp->v_interlock);
 517         imgp->vp->v_flag |= VTEXT;
 518         simple_unlock(&imgp->vp->v_interlock);
 519
 520         vmspace = imgp->proc->p_vmspace;
 521
 522         for (i = 0; i < hdr->e_phnum; i++) {
 523                 switch(phdr[i].p_type) {
 524
 525                 case PT_LOAD:   /* Loadable segment */
 526                         prot = 0;
 527                         if (phdr[i].p_flags & PF_X)
 528                                 prot |= VM_PROT_EXECUTE;
 529                         if (phdr[i].p_flags & PF_W)
 530                                 prot |= VM_PROT_WRITE;
 531                         if (phdr[i].p_flags & PF_R)
 532                                 prot |= VM_PROT_READ;
 533
 534                         if ((error = elf_load_section(imgp->proc,
 535                                                      vmspace, imgp->vp,
 536                                                      phdr[i].p_offset,
 537                                                      (caddr_t)phdr[i].p_vaddr,
 538                                                      phdr[i].p_memsz,
 539                                                      phdr[i].p_filesz, prot)) != 0)
 540                                 goto fail;
 541
 542                         seg_addr = trunc_page(phdr[i].p_vaddr);
 543                         seg_size = round_page(phdr[i].p_memsz +
 544                                 phdr[i].p_vaddr - seg_addr);
 545
 546                         /*
 547                          * Is this .text or .data?  We can't use
 548                          * VM_PROT_WRITE or VM_PROT_EXEC, it breaks the
 549                          * alpha terribly and possibly does other bad
 550                          * things so we stick to the old way of figuring
 551                          * it out:  If the segment contains the program
 552                          * entry point, it's a text segment, otherwise it
 553                          * is a data segment.
 554                          *
 555                          * Note that obreak() assumes that data_addr +
 556                          * data_size == end of data load area, and the ELF
 557                          * file format expects segments to be sorted by
 558                          * address.  If multiple data segments exist, the
 559                          * last one will be used.
 560                          */
 561                         if (hdr->e_entry >= phdr[i].p_vaddr &&
 562                             hdr->e_entry < (phdr[i].p_vaddr +
 563                             phdr[i].p_memsz)) {
 564                                 text_size = seg_size;
 565                                 text_addr = seg_addr;
 566                                 entry = (u_long)hdr->e_entry;
 567                         } else {
 568                                 data_size = seg_size;
 569                                 data_addr = seg_addr;
 570                         }
 571                         total_size += seg_size;
 572
 573                         /*
 574                          * Check limits.  It should be safe to check the
 575                          * limits after loading the segment since we do
 576                          * not actually fault in all the segment's pages.
 577                          */
 578                         if (data_size >
 579                             imgp->proc->p_rlimit[RLIMIT_DATA].rlim_cur ||
 580                             text_size > maxtsiz ||
 581                             total_size >
 582                             imgp->proc->p_rlimit[RLIMIT_VMEM].rlim_cur) {
 583                                 error = ENOMEM;
 584                                 goto fail;
 585                         }
 586                         break;
 587                 case PT_INTERP: /* Path to interpreter */
 588                         if (phdr[i].p_filesz > MAXPATHLEN ||
 589                             phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) {
 590                                 error = ENOEXEC;
 591                                 goto fail;
 592                         }
 593                         interp = imgp->image_header + phdr[i].p_offset;
 594                         break;
 595                 case PT_PHDR:   /* Program header table info */
 596                         proghdr = phdr[i].p_vaddr;
 597                         break;
 598                 default:
 599                         break;
 600                 }
 601         }
 602
 603         vmspace->vm_tsize = text_size >> PAGE_SHIFT;
 604         vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr;
 605         vmspace->vm_dsize = data_size >> PAGE_SHIFT;
 606         vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
 607
 608         addr = ELF_RTLD_ADDR(vmspace);
 609
 610         imgp->entry_addr = entry;
 611
 612         brand_info = NULL;
 613
 614         /* We support three types of branding -- (1) the ELF EI_OSABI field
 615          * that SCO added to the ELF spec, (2) FreeBSD 3.x's traditional string
 616          * branding w/in the ELF header, and (3) path of the `interp_path'
 617          * field.  We should also look for an ".note.ABI-tag" ELF section now
 618          * in all Linux ELF binaries, FreeBSD 4.1+, and some NetBSD ones.
 619          */
 620
 621         /* If the executable has a brand, search for it in the brand list. */
 622         if (brand_info == NULL) {
 623                 for (i = 0;  i < MAX_BRANDS;  i++) {
 624                         Elf_Brandinfo *bi = elf_brand_list[i];
 625
 626                         if (bi != NULL &&
 627                             (hdr->e_ident[EI_OSABI] == bi->brand
 628                             || 0 ==
 629                             strncmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
 630                             bi->compat_3_brand, strlen(bi->compat_3_brand)))) {
 631                                 brand_info = bi;
 632                                 break;
 633                         }
 634                 }
 635         }
 636
 637         /* Lacking a known brand, search for a recognized interpreter. */
 638         if (brand_info == NULL && interp != NULL) {
 639                 for (i = 0;  i < MAX_BRANDS;  i++) {
 640                         Elf_Brandinfo *bi = elf_brand_list[i];
 641
 642                         if (bi != NULL &&
 643                             strcmp(interp, bi->interp_path) == 0) {
 644                                 brand_info = bi;
 645                                 break;
 646                         }
 647                 }
 648         }
 649
 650         /* Lacking a recognized interpreter, try the default brand */
 651         if (brand_info == NULL) {
 652                 for (i = 0; i < MAX_BRANDS; i++) {
 653                         Elf_Brandinfo *bi = elf_brand_list[i];
 654
 655                         if (bi != NULL && fallback_elf_brand == bi->brand) {
 656                                 brand_info = bi;
 657                                 break;
 658                         }
 659                 }
 660         }
 661
 662         if (brand_info == NULL) {
 663                 uprintf("ELF binary type \"%u\" not known.\n",
 664                     hdr->e_ident[EI_OSABI]);
 665                 error = ENOEXEC;
 666                 goto fail;
 667         }
 668
 669         imgp->proc->p_sysent = brand_info->sysvec;
 670         if (interp != NULL) {
 671                 path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 672                 snprintf(path, MAXPATHLEN, "%s%s",
 673                          brand_info->emul_path, interp);
 674                 if ((error = elf_load_file(imgp->proc, path, &addr,
 675                                            &imgp->entry_addr)) != 0) {
 676                         if ((error = elf_load_file(imgp->proc, interp, &addr,
 677                                                    &imgp->entry_addr)) != 0) {
 678                                 uprintf("ELF interpreter %s not found\n", path);
 679                                 free(path, M_TEMP);
 680                                 goto fail;
 681                         }
 682                 }
 683                 free(path, M_TEMP);
 684         }
 685
 686         /*
 687          * Construct auxargs table (used by the fixup routine)
 688          */
 689         elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK);
 690         elf_auxargs->execfd = -1;
 691         elf_auxargs->phdr = proghdr;
 692         elf_auxargs->phent = hdr->e_phentsize;
 693         elf_auxargs->phnum = hdr->e_phnum;
 694         elf_auxargs->pagesz = PAGE_SIZE;
 695         elf_auxargs->base = addr;
 696         elf_auxargs->flags = 0;
 697         elf_auxargs->entry = entry;
 698         elf_auxargs->trace = elf_trace;
 699
 700         imgp->auxargs = elf_auxargs;
 701         imgp->interpreted = 0;
 702
 703 fail:
 704         return error;
 705 }
 706
 707 static int
 708 elf_freebsd_fixup(register_t **stack_base, struct image_params *imgp)
 709 {
 710         Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
 711         register_t *pos;
 712
 713         pos = *stack_base + (imgp->argc + imgp->envc + 2);
 714
 715         if (args->trace) {
 716                 AUXARGS_ENTRY(pos, AT_DEBUG, 1);
 717         }
 718         if (args->execfd != -1) {
 719                 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
 720         }
 721         AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
 722         AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
 723         AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
 724         AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
 725         AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
 726         AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
 727         AUXARGS_ENTRY(pos, AT_BASE, args->base);
 728         AUXARGS_ENTRY(pos, AT_NULL, 0);
 729
 730         free(imgp->auxargs, M_TEMP);
 731         imgp->auxargs = NULL;
 732
 733         (*stack_base)--;
 734         suword(*stack_base, (long) imgp->argc);
 735         return 0;
 736 }
 737
 738 /*
 739  * Code for generating ELF core dumps.
 740  */
 741
 742 typedef void (*segment_callback) __P((vm_map_entry_t, void *));
 743
 744 /* Closure for cb_put_phdr(). */
 745 struct phdr_closure {
 746         Elf_Phdr *phdr;         /* Program header to fill in */
 747         Elf_Off offset;         /* Offset of segment in core file */
 748 };
 749
 750 /* Closure for cb_size_segment(). */
 751 struct sseg_closure {
 752         int count;              /* Count of writable segments. */
 753         size_t size;            /* Total size of all writable segments. */
 754 };
 755
 756 static void cb_put_phdr __P((vm_map_entry_t, void *));
 757 static void cb_size_segment __P((vm_map_entry_t, void *));
 758 static void each_writable_segment __P((struct proc *, segment_callback,
 759     void *));
 760 static int elf_corehdr __P((struct proc *, struct vnode *, struct ucred *,
 761     int, void *, size_t));
 762 static void elf_puthdr __P((struct proc *, void *, size_t *,
 763     const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int));
 764 static void elf_putnote __P((void *, size_t *, const char *, int,
 765     const void *, size_t));
 766
 767 extern int osreldate;
 768
 769 int
 770 elf_coredump(p, vp, limit)
 771         register struct proc *p;
 772         register struct vnode *vp;
 773         off_t limit;
 774 {
 775         register struct ucred *cred = p->p_ucred;
 776         int error = 0;
 777         struct sseg_closure seginfo;
 778         void *hdr;
 779         size_t hdrsize;
 780
 781         /* Size the program segments. */
 782         seginfo.count = 0;
 783         seginfo.size = 0;
 784         each_writable_segment(p, cb_size_segment, &seginfo);
 785
 786         /*
 787          * Calculate the size of the core file header area by making
 788          * a dry run of generating it.  Nothing is written, but the
 789          * size is calculated.
 790          */
 791         hdrsize = 0;
 792         elf_puthdr((struct proc *)NULL, (void *)NULL, &hdrsize,
 793             (const prstatus_t *)NULL, (const prfpregset_t *)NULL,
 794             (const prpsinfo_t *)NULL, seginfo.count);
 795
 796         if (hdrsize + seginfo.size >= limit)
 797                 return (EFAULT);
 798
 799         /*
 800          * Allocate memory for building the header, fill it up,
 801          * and write it out.
 802          */
 803         hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
 804         if (hdr == NULL) {
 805                 return EINVAL;
 806         }
 807         error = elf_corehdr(p, vp, cred, seginfo.count, hdr, hdrsize);
 808
 809         /* Write the contents of all of the writable segments. */
 810         if (error == 0) {
 811                 Elf_Phdr *php;
 812                 off_t offset;
 813                 int i;
 814
 815                 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
 816                 offset = hdrsize;
 817                 for (i = 0;  i < seginfo.count;  i++) {
 818                         error = vn_rdwr_inchunks(UIO_WRITE, vp,
 819                             (caddr_t)php->p_vaddr,
 820                             php->p_filesz, offset, UIO_USERSPACE,
 821                             IO_UNIT | IO_DIRECT, cred, (int *)NULL, p);
 822                         if (error != 0)
 823                                 break;
 824                         offset += php->p_filesz;
 825                         php++;
 826                 }
 827         }
 828         free(hdr, M_TEMP);
 829
 830         return error;
 831 }
 832
 833 /*
 834  * A callback for each_writable_segment() to write out the segment's
 835  * program header entry.
 836  */
 837 static void
 838 cb_put_phdr(entry, closure)
 839         vm_map_entry_t entry;
 840         void *closure;
 841 {
 842         struct phdr_closure *phc = (struct phdr_closure *)closure;
 843         Elf_Phdr *phdr = phc->phdr;
 844
 845         phc->offset = round_page(phc->offset);
 846
 847         phdr->p_type = PT_LOAD;
 848         phdr->p_offset = phc->offset;
 849         phdr->p_vaddr = entry->start;
 850         phdr->p_paddr = 0;
 851         phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
 852         phdr->p_align = PAGE_SIZE;
 853         phdr->p_flags = 0;
 854         if (entry->protection & VM_PROT_READ)
 855                 phdr->p_flags |= PF_R;
 856         if (entry->protection & VM_PROT_WRITE)
 857                 phdr->p_flags |= PF_W;
 858         if (entry->protection & VM_PROT_EXECUTE)
 859                 phdr->p_flags |= PF_X;
 860
 861         phc->offset += phdr->p_filesz;
 862         phc->phdr++;
 863 }
 864
 865 /*
 866  * A callback for each_writable_segment() to gather information about
 867  * the number of segments and their total size.
 868  */
 869 static void
 870 cb_size_segment(entry, closure)
 871         vm_map_entry_t entry;
 872         void *closure;
 873 {
 874         struct sseg_closure *ssc = (struct sseg_closure *)closure;
 875
 876         ssc->count++;
 877         ssc->size += entry->end - entry->start;
 878 }
 879
 880 /*
 881  * For each writable segment in the process's memory map, call the given
 882  * function with a pointer to the map entry and some arbitrary
 883  * caller-supplied data.
 884  */
 885 static void
 886 each_writable_segment(p, func, closure)
 887         struct proc *p;
 888         segment_callback func;
 889         void *closure;
 890 {
 891         vm_map_t map = &p->p_vmspace->vm_map;
 892         vm_map_entry_t entry;
 893
 894         for (entry = map->header.next;  entry != &map->header;
 895             entry = entry->next) {
 896                 vm_object_t obj;
 897
 898                 /*
 899                  * Don't dump inaccessible mappings, deal with legacy
 900                  * coredump mode.
 901                  *
 902                  * Note that read-only segments related to the elf binary
 903                  * are marked MAP_ENTRY_NOCOREDUMP now so we no longer
 904                  * need to arbitrarily ignore such segments.
 905                  */
 906                 if (elf_legacy_coredump) {
 907                         if ((entry->protection & VM_PROT_RW) != VM_PROT_RW)
 908                                 continue;
 909                 } else {
 910                         if ((entry->protection & VM_PROT_ALL) == 0)
 911                                 continue;
 912                 }
 913
 914                 /*
 915                  * Dont include memory segment in the coredump if
 916                  * MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
 917                  * madvise(2).  Do not dump submaps (i.e. parts of the
 918                  * kernel map).
 919                  */
 920                 if (entry->eflags & (MAP_ENTRY_NOCOREDUMP|MAP_ENTRY_IS_SUB_MAP))
 921                         continue;
 922
 923                 if ((obj = entry->object.vm_object) == NULL)
 924                         continue;
 925
 926                 /* Find the deepest backing object. */
 927                 while (obj->backing_object != NULL)
 928                         obj = obj->backing_object;
 929
 930                 /* Ignore memory-mapped devices and such things. */
 931                 if (obj->type != OBJT_DEFAULT &&
 932                     obj->type != OBJT_SWAP &&
 933                     obj->type != OBJT_VNODE)
 934                         continue;
 935
 936                 (*func)(entry, closure);
 937         }
 938 }
 939
 940 /*
 941  * Write the core file header to the file, including padding up to
 942  * the page boundary.
 943  */
 944 static int
 945 elf_corehdr(p, vp, cred, numsegs, hdr, hdrsize)
 946         struct proc *p;
 947         struct vnode *vp;
 948         struct ucred *cred;
 949         int numsegs;
 950         size_t hdrsize;
 951         void *hdr;
 952 {
 953         struct {
 954                 prstatus_t status;
 955                 prfpregset_t fpregset;
 956                 prpsinfo_t psinfo;
 957         } *tempdata;
 958         size_t off;
 959         prstatus_t *status;
 960         prfpregset_t *fpregset;
 961         prpsinfo_t *psinfo;
 962
 963         tempdata = malloc(sizeof(*tempdata), M_TEMP, M_ZERO | M_WAITOK);
 964         status = &tempdata->status;
 965         fpregset = &tempdata->fpregset;
 966         psinfo = &tempdata->psinfo;
 967
 968         /* Gather the information for the header. */
 969         status->pr_version = PRSTATUS_VERSION;
 970         status->pr_statussz = sizeof(prstatus_t);
 971         status->pr_gregsetsz = sizeof(gregset_t);
 972         status->pr_fpregsetsz = sizeof(fpregset_t);
 973         status->pr_osreldate = osreldate;
 974         status->pr_cursig = p->p_sig;
 975         status->pr_pid = p->p_pid;
 976         fill_regs(p, &status->pr_reg);
 977
 978         fill_fpregs(p, fpregset);
 979
 980         psinfo->pr_version = PRPSINFO_VERSION;
 981         psinfo->pr_psinfosz = sizeof(prpsinfo_t);
 982         strncpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname) - 1);
 983
 984         /* XXX - We don't fill in the command line arguments properly yet. */
 985         strncpy(psinfo->pr_psargs, p->p_comm, PRARGSZ);
 986
 987         /* Fill in the header. */
 988         bzero(hdr, hdrsize);
 989         off = 0;
 990         elf_puthdr(p, hdr, &off, status, fpregset, psinfo, numsegs);
 991
 992         free(tempdata, M_TEMP);
 993
 994         /* Write it to the core file. */
 995         return vn_rdwr_inchunks(UIO_WRITE, vp, hdr, hdrsize, (off_t)0,
 996             UIO_SYSSPACE, IO_UNIT | IO_DIRECT, cred, NULL, p);
 997 }
 998
 999 static void
1000 elf_puthdr(struct proc *p, void *dst, size_t *off, const prstatus_t *status,
1001     const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
1002 {
1003         size_t ehoff;
1004         size_t phoff;
1005         size_t noteoff;
1006         size_t notesz;
1007
1008         ehoff = *off;
1009         *off += sizeof(Elf_Ehdr);
1010
1011         phoff = *off;
1012         *off += (numsegs + 1) * sizeof(Elf_Phdr);
1013
1014         noteoff = *off;
1015         elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
1016             sizeof *status);
1017         elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
1018             sizeof *fpregset);
1019         elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
1020             sizeof *psinfo);
1021         notesz = *off - noteoff;
1022
1023         /* Align up to a page boundary for the program segments. */
1024         *off = round_page(*off);
1025
1026         if (dst != NULL) {
1027                 Elf_Ehdr *ehdr;
1028                 Elf_Phdr *phdr;
1029                 struct phdr_closure phc;
1030
1031                 /*
1032                  * Fill in the ELF header.
1033                  */
1034                 ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
1035                 ehdr->e_ident[EI_MAG0] = ELFMAG0;
1036                 ehdr->e_ident[EI_MAG1] = ELFMAG1;
1037                 ehdr->e_ident[EI_MAG2] = ELFMAG2;
1038                 ehdr->e_ident[EI_MAG3] = ELFMAG3;
1039                 ehdr->e_ident[EI_CLASS] = ELF_CLASS;
1040                 ehdr->e_ident[EI_DATA] = ELF_DATA;
1041                 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1042                 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
1043                 ehdr->e_ident[EI_ABIVERSION] = 0;
1044                 ehdr->e_ident[EI_PAD] = 0;
1045                 ehdr->e_type = ET_CORE;
1046                 ehdr->e_machine = ELF_ARCH;
1047                 ehdr->e_version = EV_CURRENT;
1048                 ehdr->e_entry = 0;
1049                 ehdr->e_phoff = phoff;
1050                 ehdr->e_flags = 0;
1051                 ehdr->e_ehsize = sizeof(Elf_Ehdr);
1052                 ehdr->e_phentsize = sizeof(Elf_Phdr);
1053                 ehdr->e_phnum = numsegs + 1;
1054                 ehdr->e_shentsize = sizeof(Elf_Shdr);
1055                 ehdr->e_shnum = 0;
1056                 ehdr->e_shstrndx = SHN_UNDEF;
1057
1058                 /*
1059                  * Fill in the program header entries.
1060                  */
1061                 phdr = (Elf_Phdr *)((char *)dst + phoff);
1062
1063                 /* The note segement. */
1064                 phdr->p_type = PT_NOTE;
1065                 phdr->p_offset = noteoff;
1066                 phdr->p_vaddr = 0;
1067                 phdr->p_paddr = 0;
1068                 phdr->p_filesz = notesz;
1069                 phdr->p_memsz = 0;
1070                 phdr->p_flags = 0;
1071                 phdr->p_align = 0;
1072                 phdr++;
1073
1074                 /* All the writable segments from the program. */
1075                 phc.phdr = phdr;
1076                 phc.offset = *off;
1077                 each_writable_segment(p, cb_put_phdr, &phc);
1078         }
1079 }
1080
1081 static void
1082 elf_putnote(void *dst, size_t *off, const char *name, int type,
1083     const void *desc, size_t descsz)
1084 {
1085         Elf_Note note;
1086
1087         note.n_namesz = strlen(name) + 1;
1088         note.n_descsz = descsz;
1089         note.n_type = type;
1090         if (dst != NULL)
1091                 bcopy(&note, (char *)dst + *off, sizeof note);
1092         *off += sizeof note;
1093         if (dst != NULL)
1094                 bcopy(name, (char *)dst + *off, note.n_namesz);
1095         *off += roundup2(note.n_namesz, sizeof(Elf_Size));
1096         if (dst != NULL)
1097                 bcopy(desc, (char *)dst + *off, note.n_descsz);
1098         *off += roundup2(note.n_descsz, sizeof(Elf_Size));
1099 }
1100
1101 /*
1102  * Tell kern_execve.c about it, with a little help from the linker.
1103  */
1104 static struct execsw elf_execsw = {exec_elf_imgact, "ELF"};
1105 EXEC_SET(elf, elf_execsw);