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1// SPDX-License-Identifier: GPL-2.02/****************************************************************************/3/*4 * linux/fs/binfmt_flat.c5 *6 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>7 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>8 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>9 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>10 * based heavily on:11 *12 * linux/fs/binfmt_aout.c:13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds14 * linux/fs/binfmt_flat.c for 2.0 kernel15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>16 * JAN/99 -- coded full program relocation (gerg@snapgear.com)17 */18 19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt20 21#include <linux/kernel.h>22#include <linux/sched.h>23#include <linux/sched/task_stack.h>24#include <linux/mm.h>25#include <linux/mman.h>26#include <linux/errno.h>27#include <linux/signal.h>28#include <linux/string.h>29#include <linux/fs.h>30#include <linux/file.h>31#include <linux/ptrace.h>32#include <linux/user.h>33#include <linux/slab.h>34#include <linux/binfmts.h>35#include <linux/personality.h>36#include <linux/init.h>37#include <linux/flat.h>38#include <linux/uaccess.h>39#include <linux/vmalloc.h>40 41#include <asm/byteorder.h>42#include <linux/unaligned.h>43#include <asm/cacheflush.h>44#include <asm/page.h>45#include <asm/flat.h>46 47#ifndef flat_get_relocate_addr48#define flat_get_relocate_addr(rel) (rel)49#endif50 51/****************************************************************************/52 53/*54 * User data (data section and bss) needs to be aligned.55 * We pick 0x20 here because it is the max value elf2flt has always56 * used in producing FLAT files, and because it seems to be large57 * enough to make all the gcc alignment related tests happy.58 */59#define FLAT_DATA_ALIGN (0x20)60 61/*62 * User data (stack) also needs to be aligned.63 * Here we can be a bit looser than the data sections since this64 * needs to only meet arch ABI requirements.65 */66#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)67 68#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */69#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */70 71#define MAX_SHARED_LIBS (1)72 73#ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET74#define DATA_START_OFFSET_WORDS (0)75#define MAX_SHARED_LIBS_UPDATE (0)76#else77#define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS)78#define MAX_SHARED_LIBS_UPDATE (MAX_SHARED_LIBS)79#endif80 81struct lib_info {82 struct {83 unsigned long start_code; /* Start of text segment */84 unsigned long start_data; /* Start of data segment */85 unsigned long start_brk; /* End of data segment */86 unsigned long text_len; /* Length of text segment */87 unsigned long entry; /* Start address for this module */88 unsigned long build_date; /* When this one was compiled */89 bool loaded; /* Has this library been loaded? */90 } lib_list[MAX_SHARED_LIBS];91};92 93static int load_flat_binary(struct linux_binprm *);94 95static struct linux_binfmt flat_format = {96 .module = THIS_MODULE,97 .load_binary = load_flat_binary,98};99 100 101/****************************************************************************/102/*103 * create_flat_tables() parses the env- and arg-strings in new user104 * memory and creates the pointer tables from them, and puts their105 * addresses on the "stack", recording the new stack pointer value.106 */107 108static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)109{110 char __user *p;111 unsigned long __user *sp;112 long i, len;113 114 p = (char __user *)arg_start;115 sp = (unsigned long __user *)current->mm->start_stack;116 117 sp -= bprm->envc + 1;118 sp -= bprm->argc + 1;119 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))120 sp -= 2; /* argvp + envp */121 sp -= 1; /* &argc */122 123 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;124 sp = (unsigned long __user *)current->mm->start_stack;125 126 if (put_user(bprm->argc, sp++))127 return -EFAULT;128 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {129 unsigned long argv, envp;130 argv = (unsigned long)(sp + 2);131 envp = (unsigned long)(sp + 2 + bprm->argc + 1);132 if (put_user(argv, sp++) || put_user(envp, sp++))133 return -EFAULT;134 }135 136 current->mm->arg_start = (unsigned long)p;137 for (i = bprm->argc; i > 0; i--) {138 if (put_user((unsigned long)p, sp++))139 return -EFAULT;140 len = strnlen_user(p, MAX_ARG_STRLEN);141 if (!len || len > MAX_ARG_STRLEN)142 return -EINVAL;143 p += len;144 }145 if (put_user(0, sp++))146 return -EFAULT;147 current->mm->arg_end = (unsigned long)p;148 149 current->mm->env_start = (unsigned long) p;150 for (i = bprm->envc; i > 0; i--) {151 if (put_user((unsigned long)p, sp++))152 return -EFAULT;153 len = strnlen_user(p, MAX_ARG_STRLEN);154 if (!len || len > MAX_ARG_STRLEN)155 return -EINVAL;156 p += len;157 }158 if (put_user(0, sp++))159 return -EFAULT;160 current->mm->env_end = (unsigned long)p;161 162 return 0;163}164 165/****************************************************************************/166 167#ifdef CONFIG_BINFMT_ZFLAT168 169#include <linux/zlib.h>170 171#define LBUFSIZE 4000172 173/* gzip flag byte */174#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */175#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */176#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */177#define ORIG_NAME 0x08 /* bit 3 set: original file name present */178#define COMMENT 0x10 /* bit 4 set: file comment present */179#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */180#define RESERVED 0xC0 /* bit 6,7: reserved */181 182static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,183 long len, int fd)184{185 unsigned char *buf;186 z_stream strm;187 int ret, retval;188 189 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);190 191 memset(&strm, 0, sizeof(strm));192 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);193 if (!strm.workspace)194 return -ENOMEM;195 196 buf = kmalloc(LBUFSIZE, GFP_KERNEL);197 if (!buf) {198 retval = -ENOMEM;199 goto out_free;200 }201 202 /* Read in first chunk of data and parse gzip header. */203 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);204 205 strm.next_in = buf;206 strm.avail_in = ret;207 strm.total_in = 0;208 209 retval = -ENOEXEC;210 211 /* Check minimum size -- gzip header */212 if (ret < 10) {213 pr_debug("file too small?\n");214 goto out_free_buf;215 }216 217 /* Check gzip magic number */218 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {219 pr_debug("unknown compression magic?\n");220 goto out_free_buf;221 }222 223 /* Check gzip method */224 if (buf[2] != 8) {225 pr_debug("unknown compression method?\n");226 goto out_free_buf;227 }228 /* Check gzip flags */229 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||230 (buf[3] & RESERVED)) {231 pr_debug("unknown flags?\n");232 goto out_free_buf;233 }234 235 ret = 10;236 if (buf[3] & EXTRA_FIELD) {237 ret += 2 + buf[10] + (buf[11] << 8);238 if (unlikely(ret >= LBUFSIZE)) {239 pr_debug("buffer overflow (EXTRA)?\n");240 goto out_free_buf;241 }242 }243 if (buf[3] & ORIG_NAME) {244 while (ret < LBUFSIZE && buf[ret++] != 0)245 ;246 if (unlikely(ret == LBUFSIZE)) {247 pr_debug("buffer overflow (ORIG_NAME)?\n");248 goto out_free_buf;249 }250 }251 if (buf[3] & COMMENT) {252 while (ret < LBUFSIZE && buf[ret++] != 0)253 ;254 if (unlikely(ret == LBUFSIZE)) {255 pr_debug("buffer overflow (COMMENT)?\n");256 goto out_free_buf;257 }258 }259 260 strm.next_in += ret;261 strm.avail_in -= ret;262 263 strm.next_out = dst;264 strm.avail_out = len;265 strm.total_out = 0;266 267 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {268 pr_debug("zlib init failed?\n");269 goto out_free_buf;270 }271 272 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {273 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);274 if (ret <= 0)275 break;276 len -= ret;277 278 strm.next_in = buf;279 strm.avail_in = ret;280 strm.total_in = 0;281 }282 283 if (ret < 0) {284 pr_debug("decompression failed (%d), %s\n",285 ret, strm.msg);286 goto out_zlib;287 }288 289 retval = 0;290out_zlib:291 zlib_inflateEnd(&strm);292out_free_buf:293 kfree(buf);294out_free:295 kfree(strm.workspace);296 return retval;297}298 299#endif /* CONFIG_BINFMT_ZFLAT */300 301/****************************************************************************/302 303static unsigned long304calc_reloc(unsigned long r, struct lib_info *p)305{306 unsigned long addr;307 unsigned long start_brk;308 unsigned long start_data;309 unsigned long text_len;310 unsigned long start_code;311 312 start_brk = p->lib_list[0].start_brk;313 start_data = p->lib_list[0].start_data;314 start_code = p->lib_list[0].start_code;315 text_len = p->lib_list[0].text_len;316 317 if (r > start_brk - start_data + text_len) {318 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",319 r, start_brk-start_data+text_len, text_len);320 goto failed;321 }322 323 if (r < text_len) /* In text segment */324 addr = r + start_code;325 else /* In data segment */326 addr = r - text_len + start_data;327 328 /* Range checked already above so doing the range tests is redundant...*/329 return addr;330 331failed:332 pr_cont(", killing %s!\n", current->comm);333 send_sig(SIGSEGV, current, 0);334 335 return RELOC_FAILED;336}337 338/****************************************************************************/339 340#ifdef CONFIG_BINFMT_FLAT_OLD341static void old_reloc(unsigned long rl)342{343 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };344 flat_v2_reloc_t r;345 unsigned long __user *ptr;346 unsigned long val;347 348 r.value = rl;349#if defined(CONFIG_COLDFIRE)350 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);351#else352 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);353#endif354 get_user(val, ptr);355 356 pr_debug("Relocation of variable at DATASEG+%x "357 "(address %p, currently %lx) into segment %s\n",358 r.reloc.offset, ptr, val, segment[r.reloc.type]);359 360 switch (r.reloc.type) {361 case OLD_FLAT_RELOC_TYPE_TEXT:362 val += current->mm->start_code;363 break;364 case OLD_FLAT_RELOC_TYPE_DATA:365 val += current->mm->start_data;366 break;367 case OLD_FLAT_RELOC_TYPE_BSS:368 val += current->mm->end_data;369 break;370 default:371 pr_err("Unknown relocation type=%x\n", r.reloc.type);372 break;373 }374 put_user(val, ptr);375 376 pr_debug("Relocation became %lx\n", val);377}378#endif /* CONFIG_BINFMT_FLAT_OLD */379 380/****************************************************************************/381 382static inline u32 __user *skip_got_header(u32 __user *rp)383{384 if (IS_ENABLED(CONFIG_RISCV)) {385 /*386 * RISC-V has a 16 byte GOT PLT header for elf64-riscv387 * and 8 byte GOT PLT header for elf32-riscv.388 * Skip the whole GOT PLT header, since it is reserved389 * for the dynamic linker (ld.so).390 */391 u32 rp_val0, rp_val1;392 393 if (get_user(rp_val0, rp))394 return rp;395 if (get_user(rp_val1, rp + 1))396 return rp;397 398 if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff)399 rp += 4;400 else if (rp_val0 == 0xffffffff)401 rp += 2;402 }403 return rp;404}405 406static int load_flat_file(struct linux_binprm *bprm,407 struct lib_info *libinfo, unsigned long *extra_stack)408{409 struct flat_hdr *hdr;410 unsigned long textpos, datapos, realdatastart;411 u32 text_len, data_len, bss_len, stack_len, full_data, flags;412 unsigned long len, memp, memp_size, extra, rlim;413 __be32 __user *reloc;414 u32 __user *rp;415 int i, rev, relocs;416 loff_t fpos;417 unsigned long start_code, end_code;418 ssize_t result;419 int ret;420 421 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */422 423 text_len = ntohl(hdr->data_start);424 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);425 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);426 stack_len = ntohl(hdr->stack_size);427 if (extra_stack) {428 stack_len += *extra_stack;429 *extra_stack = stack_len;430 }431 relocs = ntohl(hdr->reloc_count);432 flags = ntohl(hdr->flags);433 rev = ntohl(hdr->rev);434 full_data = data_len + relocs * sizeof(unsigned long);435 436 if (strncmp(hdr->magic, "bFLT", 4)) {437 /*438 * Previously, here was a printk to tell people439 * "BINFMT_FLAT: bad header magic".440 * But for the kernel which also use ELF FD-PIC format, this441 * error message is confusing.442 * because a lot of people do not manage to produce good443 */444 ret = -ENOEXEC;445 goto err;446 }447 448 if (flags & FLAT_FLAG_KTRACE)449 pr_info("Loading file: %s\n", bprm->filename);450 451#ifdef CONFIG_BINFMT_FLAT_OLD452 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {453 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",454 rev, FLAT_VERSION, OLD_FLAT_VERSION);455 ret = -ENOEXEC;456 goto err;457 }458 459 /*460 * fix up the flags for the older format, there were all kinds461 * of endian hacks, this only works for the simple cases462 */463 if (rev == OLD_FLAT_VERSION &&464 (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))465 flags = FLAT_FLAG_RAM;466 467#else /* CONFIG_BINFMT_FLAT_OLD */468 if (rev != FLAT_VERSION) {469 pr_err("bad flat file version 0x%x (supported 0x%lx)\n",470 rev, FLAT_VERSION);471 ret = -ENOEXEC;472 goto err;473 }474#endif /* !CONFIG_BINFMT_FLAT_OLD */475 476 /*477 * Make sure the header params are sane.478 * 28 bits (256 MB) is way more than reasonable in this case.479 * If some top bits are set we have probable binary corruption.480 */481 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {482 pr_err("bad header\n");483 ret = -ENOEXEC;484 goto err;485 }486 487#ifndef CONFIG_BINFMT_ZFLAT488 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {489 pr_err("Support for ZFLAT executables is not enabled.\n");490 ret = -ENOEXEC;491 goto err;492 }493#endif494 495 /*496 * Check initial limits. This avoids letting people circumvent497 * size limits imposed on them by creating programs with large498 * arrays in the data or bss.499 */500 rlim = rlimit(RLIMIT_DATA);501 if (rlim >= RLIM_INFINITY)502 rlim = ~0;503 if (data_len + bss_len > rlim) {504 ret = -ENOMEM;505 goto err;506 }507 508 /* Flush all traces of the currently running executable */509 ret = begin_new_exec(bprm);510 if (ret)511 goto err;512 513 /* OK, This is the point of no return */514 set_personality(PER_LINUX_32BIT);515 setup_new_exec(bprm);516 517 /*518 * calculate the extra space we need to map in519 */520 extra = max_t(unsigned long, bss_len + stack_len,521 relocs * sizeof(unsigned long));522 523 /*524 * there are a couple of cases here, the separate code/data525 * case, and then the fully copied to RAM case which lumps526 * it all together.527 */528 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {529 /*530 * this should give us a ROM ptr, but if it doesn't we don't531 * really care532 */533 pr_debug("ROM mapping of file (we hope)\n");534 535 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,536 MAP_PRIVATE, 0);537 if (!textpos || IS_ERR_VALUE(textpos)) {538 ret = textpos;539 if (!textpos)540 ret = -ENOMEM;541 pr_err("Unable to mmap process text, errno %d\n", ret);542 goto err;543 }544 545 len = data_len + extra +546 DATA_START_OFFSET_WORDS * sizeof(unsigned long);547 len = PAGE_ALIGN(len);548 realdatastart = vm_mmap(NULL, 0, len,549 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);550 551 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {552 ret = realdatastart;553 if (!realdatastart)554 ret = -ENOMEM;555 pr_err("Unable to allocate RAM for process data, "556 "errno %d\n", ret);557 vm_munmap(textpos, text_len);558 goto err;559 }560 datapos = ALIGN(realdatastart +561 DATA_START_OFFSET_WORDS * sizeof(unsigned long),562 FLAT_DATA_ALIGN);563 564 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",565 data_len + bss_len + stack_len, datapos);566 567 fpos = ntohl(hdr->data_start);568#ifdef CONFIG_BINFMT_ZFLAT569 if (flags & FLAT_FLAG_GZDATA) {570 result = decompress_exec(bprm, fpos, (char *)datapos,571 full_data, 0);572 } else573#endif574 {575 result = read_code(bprm->file, datapos, fpos,576 full_data);577 }578 if (IS_ERR_VALUE(result)) {579 ret = result;580 pr_err("Unable to read data+bss, errno %d\n", ret);581 vm_munmap(textpos, text_len);582 vm_munmap(realdatastart, len);583 goto err;584 }585 586 reloc = (__be32 __user *)587 (datapos + (ntohl(hdr->reloc_start) - text_len));588 memp = realdatastart;589 memp_size = len;590 } else {591 592 len = text_len + data_len + extra +593 DATA_START_OFFSET_WORDS * sizeof(u32);594 len = PAGE_ALIGN(len);595 textpos = vm_mmap(NULL, 0, len,596 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);597 598 if (!textpos || IS_ERR_VALUE(textpos)) {599 ret = textpos;600 if (!textpos)601 ret = -ENOMEM;602 pr_err("Unable to allocate RAM for process text/data, "603 "errno %d\n", ret);604 goto err;605 }606 607 realdatastart = textpos + ntohl(hdr->data_start);608 datapos = ALIGN(realdatastart +609 DATA_START_OFFSET_WORDS * sizeof(u32),610 FLAT_DATA_ALIGN);611 612 reloc = (__be32 __user *)613 (datapos + (ntohl(hdr->reloc_start) - text_len));614 memp = textpos;615 memp_size = len;616#ifdef CONFIG_BINFMT_ZFLAT617 /*618 * load it all in and treat it like a RAM load from now on619 */620 if (flags & FLAT_FLAG_GZIP) {621#ifndef CONFIG_MMU622 result = decompress_exec(bprm, sizeof(struct flat_hdr),623 (((char *)textpos) + sizeof(struct flat_hdr)),624 (text_len + full_data625 - sizeof(struct flat_hdr)),626 0);627 memmove((void *) datapos, (void *) realdatastart,628 full_data);629#else630 /*631 * This is used on MMU systems mainly for testing.632 * Let's use a kernel buffer to simplify things.633 */634 long unz_text_len = text_len - sizeof(struct flat_hdr);635 long unz_len = unz_text_len + full_data;636 char *unz_data = vmalloc(unz_len);637 if (!unz_data) {638 result = -ENOMEM;639 } else {640 result = decompress_exec(bprm, sizeof(struct flat_hdr),641 unz_data, unz_len, 0);642 if (result == 0 &&643 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),644 unz_data, unz_text_len) ||645 copy_to_user((void __user *)datapos,646 unz_data + unz_text_len, full_data)))647 result = -EFAULT;648 vfree(unz_data);649 }650#endif651 } else if (flags & FLAT_FLAG_GZDATA) {652 result = read_code(bprm->file, textpos, 0, text_len);653 if (!IS_ERR_VALUE(result)) {654#ifndef CONFIG_MMU655 result = decompress_exec(bprm, text_len, (char *) datapos,656 full_data, 0);657#else658 char *unz_data = vmalloc(full_data);659 if (!unz_data) {660 result = -ENOMEM;661 } else {662 result = decompress_exec(bprm, text_len,663 unz_data, full_data, 0);664 if (result == 0 &&665 copy_to_user((void __user *)datapos,666 unz_data, full_data))667 result = -EFAULT;668 vfree(unz_data);669 }670#endif671 }672 } else673#endif /* CONFIG_BINFMT_ZFLAT */674 {675 result = read_code(bprm->file, textpos, 0, text_len);676 if (!IS_ERR_VALUE(result))677 result = read_code(bprm->file, datapos,678 ntohl(hdr->data_start),679 full_data);680 }681 if (IS_ERR_VALUE(result)) {682 ret = result;683 pr_err("Unable to read code+data+bss, errno %d\n", ret);684 vm_munmap(textpos, text_len + data_len + extra +685 DATA_START_OFFSET_WORDS * sizeof(u32));686 goto err;687 }688 }689 690 start_code = textpos + sizeof(struct flat_hdr);691 end_code = textpos + text_len;692 text_len -= sizeof(struct flat_hdr); /* the real code len */693 694 /* The main program needs a little extra setup in the task structure */695 current->mm->start_code = start_code;696 current->mm->end_code = end_code;697 current->mm->start_data = datapos;698 current->mm->end_data = datapos + data_len;699 /*700 * set up the brk stuff, uses any slack left in data/bss/stack701 * allocation. We put the brk after the bss (between the bss702 * and stack) like other platforms.703 * Userspace code relies on the stack pointer starting out at704 * an address right at the end of a page.705 */706 current->mm->start_brk = datapos + data_len + bss_len;707 current->mm->brk = (current->mm->start_brk + 3) & ~3;708#ifndef CONFIG_MMU709 current->mm->context.end_brk = memp + memp_size - stack_len;710#endif711 712 if (flags & FLAT_FLAG_KTRACE) {713 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",714 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));715 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",716 "Load", bprm->filename,717 start_code, end_code, datapos, datapos + data_len,718 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);719 }720 721 /* Store the current module values into the global library structure */722 libinfo->lib_list[0].start_code = start_code;723 libinfo->lib_list[0].start_data = datapos;724 libinfo->lib_list[0].start_brk = datapos + data_len + bss_len;725 libinfo->lib_list[0].text_len = text_len;726 libinfo->lib_list[0].loaded = 1;727 libinfo->lib_list[0].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;728 libinfo->lib_list[0].build_date = ntohl(hdr->build_date);729 730 /*731 * We just load the allocations into some temporary memory to732 * help simplify all this mumbo jumbo733 *734 * We've got two different sections of relocation entries.735 * The first is the GOT which resides at the beginning of the data segment736 * and is terminated with a -1. This one can be relocated in place.737 * The second is the extra relocation entries tacked after the image's738 * data segment. These require a little more processing as the entry is739 * really an offset into the image which contains an offset into the740 * image.741 */742 if (flags & FLAT_FLAG_GOTPIC) {743 rp = skip_got_header((u32 __user *) datapos);744 for (; ; rp++) {745 u32 addr, rp_val;746 if (get_user(rp_val, rp))747 return -EFAULT;748 if (rp_val == 0xffffffff)749 break;750 if (rp_val) {751 addr = calc_reloc(rp_val, libinfo);752 if (addr == RELOC_FAILED) {753 ret = -ENOEXEC;754 goto err;755 }756 if (put_user(addr, rp))757 return -EFAULT;758 }759 }760 }761 762 /*763 * Now run through the relocation entries.764 * We've got to be careful here as C++ produces relocatable zero765 * entries in the constructor and destructor tables which are then766 * tested for being not zero (which will always occur unless we're767 * based from address zero). This causes an endless loop as __start768 * is at zero. The solution used is to not relocate zero addresses.769 * This has the negative side effect of not allowing a global data770 * reference to be statically initialised to _stext (I've moved771 * __start to address 4 so that is okay).772 */773 if (rev > OLD_FLAT_VERSION) {774 for (i = 0; i < relocs; i++) {775 u32 addr, relval;776 __be32 tmp;777 778 /*779 * Get the address of the pointer to be780 * relocated (of course, the address has to be781 * relocated first).782 */783 if (get_user(tmp, reloc + i))784 return -EFAULT;785 relval = ntohl(tmp);786 addr = flat_get_relocate_addr(relval);787 rp = (u32 __user *)calc_reloc(addr, libinfo);788 if (rp == (u32 __user *)RELOC_FAILED) {789 ret = -ENOEXEC;790 goto err;791 }792 793 /* Get the pointer's value. */794 ret = flat_get_addr_from_rp(rp, relval, flags, &addr);795 if (unlikely(ret))796 goto err;797 798 if (addr != 0) {799 /*800 * Do the relocation. PIC relocs in the data section are801 * already in target order802 */803 if ((flags & FLAT_FLAG_GOTPIC) == 0) {804 /*805 * Meh, the same value can have a different806 * byte order based on a flag..807 */808 addr = ntohl((__force __be32)addr);809 }810 addr = calc_reloc(addr, libinfo);811 if (addr == RELOC_FAILED) {812 ret = -ENOEXEC;813 goto err;814 }815 816 /* Write back the relocated pointer. */817 ret = flat_put_addr_at_rp(rp, addr, relval);818 if (unlikely(ret))819 goto err;820 }821 }822#ifdef CONFIG_BINFMT_FLAT_OLD823 } else {824 for (i = 0; i < relocs; i++) {825 __be32 relval;826 if (get_user(relval, reloc + i))827 return -EFAULT;828 old_reloc(ntohl(relval));829 }830#endif /* CONFIG_BINFMT_FLAT_OLD */831 }832 833 flush_icache_user_range(start_code, end_code);834 835 /* zero the BSS, BRK and stack areas */836 if (clear_user((void __user *)(datapos + data_len), bss_len +837 (memp + memp_size - stack_len - /* end brk */838 libinfo->lib_list[0].start_brk) + /* start brk */839 stack_len))840 return -EFAULT;841 842 return 0;843err:844 return ret;845}846 847 848/****************************************************************************/849 850/*851 * These are the functions used to load flat style executables and shared852 * libraries. There is no binary dependent code anywhere else.853 */854 855static int load_flat_binary(struct linux_binprm *bprm)856{857 struct lib_info libinfo;858 struct pt_regs *regs = current_pt_regs();859 unsigned long stack_len = 0;860 unsigned long start_addr;861 int res;862 int i, j;863 864 memset(&libinfo, 0, sizeof(libinfo));865 866 /*867 * We have to add the size of our arguments to our stack size868 * otherwise it's too easy for users to create stack overflows869 * by passing in a huge argument list. And yes, we have to be870 * pedantic and include space for the argv/envp array as it may have871 * a lot of entries.872 */873#ifndef CONFIG_MMU874 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */875#endif876 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */877 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */878 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);879 880 res = load_flat_file(bprm, &libinfo, &stack_len);881 if (res < 0)882 return res;883 884 /* Update data segment pointers for all libraries */885 for (i = 0; i < MAX_SHARED_LIBS_UPDATE; i++) {886 if (!libinfo.lib_list[i].loaded)887 continue;888 for (j = 0; j < MAX_SHARED_LIBS; j++) {889 unsigned long val = libinfo.lib_list[j].loaded ?890 libinfo.lib_list[j].start_data : UNLOADED_LIB;891 unsigned long __user *p = (unsigned long __user *)892 libinfo.lib_list[i].start_data;893 p -= j + 1;894 if (put_user(val, p))895 return -EFAULT;896 }897 }898 899 set_binfmt(&flat_format);900 901#ifdef CONFIG_MMU902 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);903 if (!res)904 res = create_flat_tables(bprm, bprm->p);905#else906 /* Stash our initial stack pointer into the mm structure */907 current->mm->start_stack =908 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;909 pr_debug("sp=%lx\n", current->mm->start_stack);910 911 /* copy the arg pages onto the stack */912 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack);913 if (!res)914 res = create_flat_tables(bprm, current->mm->start_stack);915#endif916 if (res)917 return res;918 919 /* Fake some return addresses to ensure the call chain will920 * initialise library in order for us. We are required to call921 * lib 1 first, then 2, ... and finally the main program (id 0).922 */923 start_addr = libinfo.lib_list[0].entry;924 925#ifdef FLAT_PLAT_INIT926 FLAT_PLAT_INIT(regs);927#endif928 929 finalize_exec(bprm);930 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",931 regs, start_addr, current->mm->start_stack);932 start_thread(regs, start_addr, current->mm->start_stack);933 934 return 0;935}936 937/****************************************************************************/938 939static int __init init_flat_binfmt(void)940{941 register_binfmt(&flat_format);942 return 0;943}944core_initcall(init_flat_binfmt);945 946/****************************************************************************/947