1 // SPDX-License-Identifier: GPL-2.0
2 /****************************************************************************/
4 * linux/fs/binfmt_flat.c
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>
12 * linux/fs/binfmt_aout.c:
13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
14 * linux/fs/binfmt_flat.c for 2.0 kernel
15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
16 * JAN/99 -- coded full program relocation (gerg@snapgear.com)
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/kernel.h>
22 #include <linux/sched.h>
23 #include <linux/sched/task_stack.h>
25 #include <linux/mman.h>
26 #include <linux/errno.h>
27 #include <linux/signal.h>
28 #include <linux/string.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>
41 #include <asm/byteorder.h>
42 #include <asm/unaligned.h>
43 #include <asm/cacheflush.h>
46 /****************************************************************************/
49 * User data (data section and bss) needs to be aligned.
50 * We pick 0x20 here because it is the max value elf2flt has always
51 * used in producing FLAT files, and because it seems to be large
52 * enough to make all the gcc alignment related tests happy.
54 #define FLAT_DATA_ALIGN (0x20)
57 * User data (stack) also needs to be aligned.
58 * Here we can be a bit looser than the data sections since this
59 * needs to only meet arch ABI requirements.
61 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
63 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
64 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
68 unsigned long start_code; /* Start of text segment */
69 unsigned long start_data; /* Start of data segment */
70 unsigned long start_brk; /* End of data segment */
71 unsigned long text_len; /* Length of text segment */
72 unsigned long entry; /* Start address for this module */
73 unsigned long build_date; /* When this one was compiled */
74 bool loaded; /* Has this library been loaded? */
75 } lib_list[MAX_SHARED_LIBS];
78 #ifdef CONFIG_BINFMT_SHARED_FLAT
79 static int load_flat_shared_library(int id, struct lib_info *p);
82 static int load_flat_binary(struct linux_binprm *);
83 static int flat_core_dump(struct coredump_params *cprm);
85 static struct linux_binfmt flat_format = {
86 .module = THIS_MODULE,
87 .load_binary = load_flat_binary,
88 .core_dump = flat_core_dump,
89 .min_coredump = PAGE_SIZE
92 /****************************************************************************/
94 * Routine writes a core dump image in the current directory.
95 * Currently only a stub-function.
98 static int flat_core_dump(struct coredump_params *cprm)
100 pr_warn("Process %s:%d received signr %d and should have core dumped\n",
101 current->comm, current->pid, cprm->siginfo->si_signo);
105 /****************************************************************************/
107 * create_flat_tables() parses the env- and arg-strings in new user
108 * memory and creates the pointer tables from them, and puts their
109 * addresses on the "stack", recording the new stack pointer value.
112 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
115 unsigned long __user *sp;
118 p = (char __user *)arg_start;
119 sp = (unsigned long __user *)current->mm->start_stack;
121 sp -= bprm->envc + 1;
122 sp -= bprm->argc + 1;
123 sp -= flat_argvp_envp_on_stack() ? 2 : 0;
126 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
127 sp = (unsigned long __user *)current->mm->start_stack;
129 __put_user(bprm->argc, sp++);
130 if (flat_argvp_envp_on_stack()) {
131 unsigned long argv, envp;
132 argv = (unsigned long)(sp + 2);
133 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
134 __put_user(argv, sp++);
135 __put_user(envp, sp++);
138 current->mm->arg_start = (unsigned long)p;
139 for (i = bprm->argc; i > 0; i--) {
140 __put_user((unsigned long)p, sp++);
141 len = strnlen_user(p, MAX_ARG_STRLEN);
142 if (!len || len > MAX_ARG_STRLEN)
147 current->mm->arg_end = (unsigned long)p;
149 current->mm->env_start = (unsigned long) p;
150 for (i = bprm->envc; i > 0; i--) {
151 __put_user((unsigned long)p, sp++);
152 len = strnlen_user(p, MAX_ARG_STRLEN);
153 if (!len || len > MAX_ARG_STRLEN)
158 current->mm->env_end = (unsigned long)p;
163 /****************************************************************************/
165 #ifdef CONFIG_BINFMT_ZFLAT
167 #include <linux/zlib.h>
169 #define LBUFSIZE 4000
172 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
173 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
174 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
175 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
176 #define COMMENT 0x10 /* bit 4 set: file comment present */
177 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
178 #define RESERVED 0xC0 /* bit 6,7: reserved */
180 static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
187 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
189 memset(&strm, 0, sizeof(strm));
190 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
194 buf = kmalloc(LBUFSIZE, GFP_KERNEL);
200 /* Read in first chunk of data and parse gzip header. */
201 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
209 /* Check minimum size -- gzip header */
211 pr_debug("file too small?\n");
215 /* Check gzip magic number */
216 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
217 pr_debug("unknown compression magic?\n");
221 /* Check gzip method */
223 pr_debug("unknown compression method?\n");
226 /* Check gzip flags */
227 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
228 (buf[3] & RESERVED)) {
229 pr_debug("unknown flags?\n");
234 if (buf[3] & EXTRA_FIELD) {
235 ret += 2 + buf[10] + (buf[11] << 8);
236 if (unlikely(ret >= LBUFSIZE)) {
237 pr_debug("buffer overflow (EXTRA)?\n");
241 if (buf[3] & ORIG_NAME) {
242 while (ret < LBUFSIZE && buf[ret++] != 0)
244 if (unlikely(ret == LBUFSIZE)) {
245 pr_debug("buffer overflow (ORIG_NAME)?\n");
249 if (buf[3] & COMMENT) {
250 while (ret < LBUFSIZE && buf[ret++] != 0)
252 if (unlikely(ret == LBUFSIZE)) {
253 pr_debug("buffer overflow (COMMENT)?\n");
259 strm.avail_in -= ret;
262 strm.avail_out = len;
265 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
266 pr_debug("zlib init failed?\n");
270 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
271 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
282 pr_debug("decompression failed (%d), %s\n",
289 zlib_inflateEnd(&strm);
293 kfree(strm.workspace);
297 #endif /* CONFIG_BINFMT_ZFLAT */
299 /****************************************************************************/
302 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
306 unsigned long start_brk;
307 unsigned long start_data;
308 unsigned long text_len;
309 unsigned long start_code;
311 #ifdef CONFIG_BINFMT_SHARED_FLAT
313 id = curid; /* Relocs of 0 are always self referring */
315 id = (r >> 24) & 0xff; /* Find ID for this reloc */
316 r &= 0x00ffffff; /* Trim ID off here */
318 if (id >= MAX_SHARED_LIBS) {
319 pr_err("reference 0x%lx to shared library %d", r, id);
324 pr_err("reloc address 0x%lx not in same module "
325 "(%d != %d)", r, curid, id);
327 } else if (!p->lib_list[id].loaded &&
328 load_flat_shared_library(id, p) < 0) {
329 pr_err("failed to load library %d", id);
332 /* Check versioning information (i.e. time stamps) */
333 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
334 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
335 pr_err("library %d is younger than %d", id, curid);
343 start_brk = p->lib_list[id].start_brk;
344 start_data = p->lib_list[id].start_data;
345 start_code = p->lib_list[id].start_code;
346 text_len = p->lib_list[id].text_len;
348 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
349 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
350 r, start_brk-start_data+text_len, text_len);
354 if (r < text_len) /* In text segment */
355 addr = r + start_code;
356 else /* In data segment */
357 addr = r - text_len + start_data;
359 /* Range checked already above so doing the range tests is redundant...*/
363 pr_cont(", killing %s!\n", current->comm);
364 send_sig(SIGSEGV, current, 0);
369 /****************************************************************************/
371 static void old_reloc(unsigned long rl)
373 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
375 unsigned long __user *ptr;
379 #if defined(CONFIG_COLDFIRE)
380 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
382 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
386 pr_debug("Relocation of variable at DATASEG+%x "
387 "(address %p, currently %lx) into segment %s\n",
388 r.reloc.offset, ptr, val, segment[r.reloc.type]);
390 switch (r.reloc.type) {
391 case OLD_FLAT_RELOC_TYPE_TEXT:
392 val += current->mm->start_code;
394 case OLD_FLAT_RELOC_TYPE_DATA:
395 val += current->mm->start_data;
397 case OLD_FLAT_RELOC_TYPE_BSS:
398 val += current->mm->end_data;
401 pr_err("Unknown relocation type=%x\n", r.reloc.type);
406 pr_debug("Relocation became %lx\n", val);
409 /****************************************************************************/
411 static inline u32 __user *skip_got_header(u32 __user *rp)
413 if (IS_ENABLED(CONFIG_RISCV)) {
415 * RISC-V has a 16 byte GOT PLT header for elf64-riscv
416 * and 8 byte GOT PLT header for elf32-riscv.
417 * Skip the whole GOT PLT header, since it is reserved
418 * for the dynamic linker (ld.so).
420 u32 rp_val0, rp_val1;
422 if (get_user(rp_val0, rp))
424 if (get_user(rp_val1, rp + 1))
427 if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff)
429 else if (rp_val0 == 0xffffffff)
435 static int load_flat_file(struct linux_binprm *bprm,
436 struct lib_info *libinfo, int id, unsigned long *extra_stack)
438 struct flat_hdr *hdr;
439 unsigned long textpos, datapos, realdatastart;
440 u32 text_len, data_len, bss_len, stack_len, full_data, flags;
441 unsigned long len, memp, memp_size, extra, rlim;
442 u32 __user *reloc, *rp;
446 unsigned long start_code, end_code;
450 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
451 inode = file_inode(bprm->file);
453 text_len = ntohl(hdr->data_start);
454 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
455 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
456 stack_len = ntohl(hdr->stack_size);
458 stack_len += *extra_stack;
459 *extra_stack = stack_len;
461 relocs = ntohl(hdr->reloc_count);
462 flags = ntohl(hdr->flags);
463 rev = ntohl(hdr->rev);
464 full_data = data_len + relocs * sizeof(unsigned long);
466 if (strncmp(hdr->magic, "bFLT", 4)) {
468 * Previously, here was a printk to tell people
469 * "BINFMT_FLAT: bad header magic".
470 * But for the kernel which also use ELF FD-PIC format, this
471 * error message is confusing.
472 * because a lot of people do not manage to produce good
478 if (flags & FLAT_FLAG_KTRACE)
479 pr_info("Loading file: %s\n", bprm->filename);
481 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
482 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
483 rev, FLAT_VERSION, OLD_FLAT_VERSION);
488 /* Don't allow old format executables to use shared libraries */
489 if (rev == OLD_FLAT_VERSION && id != 0) {
490 pr_err("shared libraries are not available before rev 0x%lx\n",
497 * Make sure the header params are sane.
498 * 28 bits (256 MB) is way more than reasonable in this case.
499 * If some top bits are set we have probable binary corruption.
501 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
502 pr_err("bad header\n");
508 * fix up the flags for the older format, there were all kinds
509 * of endian hacks, this only works for the simple cases
511 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
512 flags = FLAT_FLAG_RAM;
514 #ifndef CONFIG_BINFMT_ZFLAT
515 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
516 pr_err("Support for ZFLAT executables is not enabled.\n");
523 * Check initial limits. This avoids letting people circumvent
524 * size limits imposed on them by creating programs with large
525 * arrays in the data or bss.
527 rlim = rlimit(RLIMIT_DATA);
528 if (rlim >= RLIM_INFINITY)
530 if (data_len + bss_len > rlim) {
535 /* Flush all traces of the currently running executable */
537 ret = flush_old_exec(bprm);
541 /* OK, This is the point of no return */
542 set_personality(PER_LINUX_32BIT);
543 setup_new_exec(bprm);
547 * calculate the extra space we need to map in
549 extra = max_t(unsigned long, bss_len + stack_len,
550 relocs * sizeof(unsigned long));
553 * there are a couple of cases here, the separate code/data
554 * case, and then the fully copied to RAM case which lumps
557 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
559 * this should give us a ROM ptr, but if it doesn't we don't
562 pr_debug("ROM mapping of file (we hope)\n");
564 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
565 MAP_PRIVATE|MAP_EXECUTABLE, 0);
566 if (!textpos || IS_ERR_VALUE(textpos)) {
570 pr_err("Unable to mmap process text, errno %d\n", ret);
574 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
575 len = PAGE_ALIGN(len);
576 realdatastart = vm_mmap(NULL, 0, len,
577 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
579 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
583 pr_err("Unable to allocate RAM for process data, "
585 vm_munmap(textpos, text_len);
588 datapos = ALIGN(realdatastart +
589 MAX_SHARED_LIBS * sizeof(unsigned long),
592 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
593 data_len + bss_len + stack_len, datapos);
595 fpos = ntohl(hdr->data_start);
596 #ifdef CONFIG_BINFMT_ZFLAT
597 if (flags & FLAT_FLAG_GZDATA) {
598 result = decompress_exec(bprm, fpos, (char *)datapos,
603 result = read_code(bprm->file, datapos, fpos,
606 if (IS_ERR_VALUE(result)) {
608 pr_err("Unable to read data+bss, errno %d\n", ret);
609 vm_munmap(textpos, text_len);
610 vm_munmap(realdatastart, len);
614 reloc = (u32 __user *)
615 (datapos + (ntohl(hdr->reloc_start) - text_len));
616 memp = realdatastart;
620 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32);
621 len = PAGE_ALIGN(len);
622 textpos = vm_mmap(NULL, 0, len,
623 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
625 if (!textpos || IS_ERR_VALUE(textpos)) {
629 pr_err("Unable to allocate RAM for process text/data, "
634 realdatastart = textpos + ntohl(hdr->data_start);
635 datapos = ALIGN(realdatastart +
636 MAX_SHARED_LIBS * sizeof(u32),
639 reloc = (u32 __user *)
640 (datapos + (ntohl(hdr->reloc_start) - text_len));
643 #ifdef CONFIG_BINFMT_ZFLAT
645 * load it all in and treat it like a RAM load from now on
647 if (flags & FLAT_FLAG_GZIP) {
649 result = decompress_exec(bprm, sizeof(struct flat_hdr),
650 (((char *)textpos) + sizeof(struct flat_hdr)),
651 (text_len + full_data
652 - sizeof(struct flat_hdr)),
654 memmove((void *) datapos, (void *) realdatastart,
658 * This is used on MMU systems mainly for testing.
659 * Let's use a kernel buffer to simplify things.
661 long unz_text_len = text_len - sizeof(struct flat_hdr);
662 long unz_len = unz_text_len + full_data;
663 char *unz_data = vmalloc(unz_len);
667 result = decompress_exec(bprm, sizeof(struct flat_hdr),
668 unz_data, unz_len, 0);
670 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
671 unz_data, unz_text_len) ||
672 copy_to_user((void __user *)datapos,
673 unz_data + unz_text_len, full_data)))
678 } else if (flags & FLAT_FLAG_GZDATA) {
679 result = read_code(bprm->file, textpos, 0, text_len);
680 if (!IS_ERR_VALUE(result)) {
682 result = decompress_exec(bprm, text_len, (char *) datapos,
685 char *unz_data = vmalloc(full_data);
689 result = decompress_exec(bprm, text_len,
690 unz_data, full_data, 0);
692 copy_to_user((void __user *)datapos,
693 unz_data, full_data))
700 #endif /* CONFIG_BINFMT_ZFLAT */
702 result = read_code(bprm->file, textpos, 0, text_len);
703 if (!IS_ERR_VALUE(result))
704 result = read_code(bprm->file, datapos,
705 ntohl(hdr->data_start),
708 if (IS_ERR_VALUE(result)) {
710 pr_err("Unable to read code+data+bss, errno %d\n", ret);
711 vm_munmap(textpos, text_len + data_len + extra +
712 MAX_SHARED_LIBS * sizeof(u32));
717 start_code = textpos + sizeof(struct flat_hdr);
718 end_code = textpos + text_len;
719 text_len -= sizeof(struct flat_hdr); /* the real code len */
721 /* The main program needs a little extra setup in the task structure */
723 current->mm->start_code = start_code;
724 current->mm->end_code = end_code;
725 current->mm->start_data = datapos;
726 current->mm->end_data = datapos + data_len;
728 * set up the brk stuff, uses any slack left in data/bss/stack
729 * allocation. We put the brk after the bss (between the bss
730 * and stack) like other platforms.
731 * Userspace code relies on the stack pointer starting out at
732 * an address right at the end of a page.
734 current->mm->start_brk = datapos + data_len + bss_len;
735 current->mm->brk = (current->mm->start_brk + 3) & ~3;
737 current->mm->context.end_brk = memp + memp_size - stack_len;
741 if (flags & FLAT_FLAG_KTRACE) {
742 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
743 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
744 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
745 id ? "Lib" : "Load", bprm->filename,
746 start_code, end_code, datapos, datapos + data_len,
747 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
750 /* Store the current module values into the global library structure */
751 libinfo->lib_list[id].start_code = start_code;
752 libinfo->lib_list[id].start_data = datapos;
753 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
754 libinfo->lib_list[id].text_len = text_len;
755 libinfo->lib_list[id].loaded = 1;
756 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
757 libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
760 * We just load the allocations into some temporary memory to
761 * help simplify all this mumbo jumbo
763 * We've got two different sections of relocation entries.
764 * The first is the GOT which resides at the beginning of the data segment
765 * and is terminated with a -1. This one can be relocated in place.
766 * The second is the extra relocation entries tacked after the image's
767 * data segment. These require a little more processing as the entry is
768 * really an offset into the image which contains an offset into the
771 if (flags & FLAT_FLAG_GOTPIC) {
772 rp = skip_got_header((u32 __user *) datapos);
775 if (get_user(rp_val, rp))
777 if (rp_val == 0xffffffff)
780 addr = calc_reloc(rp_val, libinfo, id, 0);
781 if (addr == RELOC_FAILED) {
785 if (put_user(addr, rp))
792 * Now run through the relocation entries.
793 * We've got to be careful here as C++ produces relocatable zero
794 * entries in the constructor and destructor tables which are then
795 * tested for being not zero (which will always occur unless we're
796 * based from address zero). This causes an endless loop as __start
797 * is at zero. The solution used is to not relocate zero addresses.
798 * This has the negative side effect of not allowing a global data
799 * reference to be statically initialised to _stext (I've moved
800 * __start to address 4 so that is okay).
802 if (rev > OLD_FLAT_VERSION) {
803 u32 __maybe_unused persistent = 0;
804 for (i = 0; i < relocs; i++) {
808 * Get the address of the pointer to be
809 * relocated (of course, the address has to be
812 if (get_user(relval, reloc + i))
814 relval = ntohl(relval);
815 if (flat_set_persistent(relval, &persistent))
817 addr = flat_get_relocate_addr(relval);
818 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
819 if (rp == (u32 __user *)RELOC_FAILED) {
824 /* Get the pointer's value. */
825 ret = flat_get_addr_from_rp(rp, relval, flags,
832 * Do the relocation. PIC relocs in the data section are
833 * already in target order
835 if ((flags & FLAT_FLAG_GOTPIC) == 0)
837 addr = calc_reloc(addr, libinfo, id, 0);
838 if (addr == RELOC_FAILED) {
843 /* Write back the relocated pointer. */
844 ret = flat_put_addr_at_rp(rp, addr, relval);
850 for (i = 0; i < relocs; i++) {
852 if (get_user(relval, reloc + i))
854 relval = ntohl(relval);
859 flush_icache_range(start_code, end_code);
861 /* zero the BSS, BRK and stack areas */
862 if (clear_user((void __user *)(datapos + data_len), bss_len +
863 (memp + memp_size - stack_len - /* end brk */
864 libinfo->lib_list[id].start_brk) + /* start brk */
874 /****************************************************************************/
875 #ifdef CONFIG_BINFMT_SHARED_FLAT
878 * Load a shared library into memory. The library gets its own data
879 * segment (including bss) but not argv/argc/environ.
882 static int load_flat_shared_library(int id, struct lib_info *libs)
885 * This is a fake bprm struct; only the members "buf", "file" and
886 * "filename" are actually used.
888 struct linux_binprm bprm;
893 memset(&bprm, 0, sizeof(bprm));
895 /* Create the file name */
896 sprintf(buf, "/lib/lib%d.so", id);
898 /* Open the file up */
900 bprm.file = open_exec(bprm.filename);
901 res = PTR_ERR(bprm.file);
902 if (IS_ERR(bprm.file))
905 res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos);
908 res = load_flat_file(&bprm, libs, id, NULL);
910 allow_write_access(bprm.file);
916 #endif /* CONFIG_BINFMT_SHARED_FLAT */
917 /****************************************************************************/
920 * These are the functions used to load flat style executables and shared
921 * libraries. There is no binary dependent code anywhere else.
924 static int load_flat_binary(struct linux_binprm *bprm)
926 struct lib_info libinfo;
927 struct pt_regs *regs = current_pt_regs();
928 unsigned long stack_len = 0;
929 unsigned long start_addr;
933 memset(&libinfo, 0, sizeof(libinfo));
936 * We have to add the size of our arguments to our stack size
937 * otherwise it's too easy for users to create stack overflows
938 * by passing in a huge argument list. And yes, we have to be
939 * pedantic and include space for the argv/envp array as it may have
943 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
945 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
946 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
947 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
949 res = load_flat_file(bprm, &libinfo, 0, &stack_len);
953 /* Update data segment pointers for all libraries */
954 for (i = 0; i < MAX_SHARED_LIBS; i++) {
955 if (!libinfo.lib_list[i].loaded)
957 for (j = 0; j < MAX_SHARED_LIBS; j++) {
958 unsigned long val = libinfo.lib_list[j].loaded ?
959 libinfo.lib_list[j].start_data : UNLOADED_LIB;
960 unsigned long __user *p = (unsigned long __user *)
961 libinfo.lib_list[i].start_data;
963 if (put_user(val, p))
968 install_exec_creds(bprm);
970 set_binfmt(&flat_format);
973 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
975 res = create_flat_tables(bprm, bprm->p);
977 /* Stash our initial stack pointer into the mm structure */
978 current->mm->start_stack =
979 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
980 pr_debug("sp=%lx\n", current->mm->start_stack);
982 /* copy the arg pages onto the stack */
983 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack);
985 res = create_flat_tables(bprm, current->mm->start_stack);
990 /* Fake some return addresses to ensure the call chain will
991 * initialise library in order for us. We are required to call
992 * lib 1 first, then 2, ... and finally the main program (id 0).
994 start_addr = libinfo.lib_list[0].entry;
996 #ifdef CONFIG_BINFMT_SHARED_FLAT
997 for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
998 if (libinfo.lib_list[i].loaded) {
999 /* Push previos first to call address */
1000 unsigned long __user *sp;
1001 current->mm->start_stack -= sizeof(unsigned long);
1002 sp = (unsigned long __user *)current->mm->start_stack;
1003 __put_user(start_addr, sp);
1004 start_addr = libinfo.lib_list[i].entry;
1009 #ifdef FLAT_PLAT_INIT
1010 FLAT_PLAT_INIT(regs);
1013 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
1014 regs, start_addr, current->mm->start_stack);
1015 start_thread(regs, start_addr, current->mm->start_stack);
1020 /****************************************************************************/
1022 static int __init init_flat_binfmt(void)
1024 register_binfmt(&flat_format);
1027 core_initcall(init_flat_binfmt);
1029 /****************************************************************************/