Root/fs/binfmt_elf_fdpic.c

1/* binfmt_elf_fdpic.c: FDPIC ELF binary format
2 *
3 * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * Derived from binfmt_elf.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/module.h>
14
15#include <linux/fs.h>
16#include <linux/stat.h>
17#include <linux/sched.h>
18#include <linux/mm.h>
19#include <linux/mman.h>
20#include <linux/errno.h>
21#include <linux/signal.h>
22#include <linux/binfmts.h>
23#include <linux/string.h>
24#include <linux/file.h>
25#include <linux/fcntl.h>
26#include <linux/slab.h>
27#include <linux/pagemap.h>
28#include <linux/security.h>
29#include <linux/highmem.h>
30#include <linux/highuid.h>
31#include <linux/personality.h>
32#include <linux/ptrace.h>
33#include <linux/init.h>
34#include <linux/elf.h>
35#include <linux/elf-fdpic.h>
36#include <linux/elfcore.h>
37#include <linux/coredump.h>
38
39#include <asm/uaccess.h>
40#include <asm/param.h>
41#include <asm/pgalloc.h>
42
43typedef char *elf_caddr_t;
44
45#if 0
46#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
47#else
48#define kdebug(fmt, ...) do {} while(0)
49#endif
50
51#if 0
52#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
53#else
54#define kdcore(fmt, ...) do {} while(0)
55#endif
56
57MODULE_LICENSE("GPL");
58
59static int load_elf_fdpic_binary(struct linux_binprm *, struct pt_regs *);
60static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
61static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
62                  struct mm_struct *, const char *);
63
64static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
65                   struct elf_fdpic_params *,
66                   struct elf_fdpic_params *);
67
68#ifndef CONFIG_MMU
69static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *,
70                        unsigned long *);
71static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
72                           struct file *,
73                           struct mm_struct *);
74#endif
75
76static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
77                         struct file *, struct mm_struct *);
78
79#ifdef CONFIG_ELF_CORE
80static int elf_fdpic_core_dump(struct coredump_params *cprm);
81#endif
82
83static struct linux_binfmt elf_fdpic_format = {
84    .module = THIS_MODULE,
85    .load_binary = load_elf_fdpic_binary,
86#ifdef CONFIG_ELF_CORE
87    .core_dump = elf_fdpic_core_dump,
88#endif
89    .min_coredump = ELF_EXEC_PAGESIZE,
90};
91
92static int __init init_elf_fdpic_binfmt(void)
93{
94    return register_binfmt(&elf_fdpic_format);
95}
96
97static void __exit exit_elf_fdpic_binfmt(void)
98{
99    unregister_binfmt(&elf_fdpic_format);
100}
101
102core_initcall(init_elf_fdpic_binfmt);
103module_exit(exit_elf_fdpic_binfmt);
104
105static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
106{
107    if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
108        return 0;
109    if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
110        return 0;
111    if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
112        return 0;
113    if (!file->f_op || !file->f_op->mmap)
114        return 0;
115    return 1;
116}
117
118/*****************************************************************************/
119/*
120 * read the program headers table into memory
121 */
122static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
123                 struct file *file)
124{
125    struct elf32_phdr *phdr;
126    unsigned long size;
127    int retval, loop;
128
129    if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
130        return -ENOMEM;
131    if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
132        return -ENOMEM;
133
134    size = params->hdr.e_phnum * sizeof(struct elf_phdr);
135    params->phdrs = kmalloc(size, GFP_KERNEL);
136    if (!params->phdrs)
137        return -ENOMEM;
138
139    retval = kernel_read(file, params->hdr.e_phoff,
140                 (char *) params->phdrs, size);
141    if (unlikely(retval != size))
142        return retval < 0 ? retval : -ENOEXEC;
143
144    /* determine stack size for this binary */
145    phdr = params->phdrs;
146    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
147        if (phdr->p_type != PT_GNU_STACK)
148            continue;
149
150        if (phdr->p_flags & PF_X)
151            params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
152        else
153            params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
154
155        params->stack_size = phdr->p_memsz;
156        break;
157    }
158
159    return 0;
160}
161
162/*****************************************************************************/
163/*
164 * load an fdpic binary into various bits of memory
165 */
166static int load_elf_fdpic_binary(struct linux_binprm *bprm,
167                 struct pt_regs *regs)
168{
169    struct elf_fdpic_params exec_params, interp_params;
170    struct elf_phdr *phdr;
171    unsigned long stack_size, entryaddr;
172#ifdef ELF_FDPIC_PLAT_INIT
173    unsigned long dynaddr;
174#endif
175#ifndef CONFIG_MMU
176    unsigned long stack_prot;
177#endif
178    struct file *interpreter = NULL; /* to shut gcc up */
179    char *interpreter_name = NULL;
180    int executable_stack;
181    int retval, i;
182
183    kdebug("____ LOAD %d ____", current->pid);
184
185    memset(&exec_params, 0, sizeof(exec_params));
186    memset(&interp_params, 0, sizeof(interp_params));
187
188    exec_params.hdr = *(struct elfhdr *) bprm->buf;
189    exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
190
191    /* check that this is a binary we know how to deal with */
192    retval = -ENOEXEC;
193    if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
194        goto error;
195
196    /* read the program header table */
197    retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
198    if (retval < 0)
199        goto error;
200
201    /* scan for a program header that specifies an interpreter */
202    phdr = exec_params.phdrs;
203
204    for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
205        switch (phdr->p_type) {
206        case PT_INTERP:
207            retval = -ENOMEM;
208            if (phdr->p_filesz > PATH_MAX)
209                goto error;
210            retval = -ENOENT;
211            if (phdr->p_filesz < 2)
212                goto error;
213
214            /* read the name of the interpreter into memory */
215            interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
216            if (!interpreter_name)
217                goto error;
218
219            retval = kernel_read(bprm->file,
220                         phdr->p_offset,
221                         interpreter_name,
222                         phdr->p_filesz);
223            if (unlikely(retval != phdr->p_filesz)) {
224                if (retval >= 0)
225                    retval = -ENOEXEC;
226                goto error;
227            }
228
229            retval = -ENOENT;
230            if (interpreter_name[phdr->p_filesz - 1] != '\0')
231                goto error;
232
233            kdebug("Using ELF interpreter %s", interpreter_name);
234
235            /* replace the program with the interpreter */
236            interpreter = open_exec(interpreter_name);
237            retval = PTR_ERR(interpreter);
238            if (IS_ERR(interpreter)) {
239                interpreter = NULL;
240                goto error;
241            }
242
243            /*
244             * If the binary is not readable then enforce
245             * mm->dumpable = 0 regardless of the interpreter's
246             * permissions.
247             */
248            if (file_permission(interpreter, MAY_READ) < 0)
249                bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
250
251            retval = kernel_read(interpreter, 0, bprm->buf,
252                         BINPRM_BUF_SIZE);
253            if (unlikely(retval != BINPRM_BUF_SIZE)) {
254                if (retval >= 0)
255                    retval = -ENOEXEC;
256                goto error;
257            }
258
259            interp_params.hdr = *((struct elfhdr *) bprm->buf);
260            break;
261
262        case PT_LOAD:
263#ifdef CONFIG_MMU
264            if (exec_params.load_addr == 0)
265                exec_params.load_addr = phdr->p_vaddr;
266#endif
267            break;
268        }
269
270    }
271
272    if (elf_check_const_displacement(&exec_params.hdr))
273        exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
274
275    /* perform insanity checks on the interpreter */
276    if (interpreter_name) {
277        retval = -ELIBBAD;
278        if (!is_elf_fdpic(&interp_params.hdr, interpreter))
279            goto error;
280
281        interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
282
283        /* read the interpreter's program header table */
284        retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
285        if (retval < 0)
286            goto error;
287    }
288
289    stack_size = exec_params.stack_size;
290    if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
291        executable_stack = EXSTACK_ENABLE_X;
292    else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
293        executable_stack = EXSTACK_DISABLE_X;
294    else
295        executable_stack = EXSTACK_DEFAULT;
296
297    if (stack_size == 0) {
298        stack_size = interp_params.stack_size;
299        if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
300            executable_stack = EXSTACK_ENABLE_X;
301        else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
302            executable_stack = EXSTACK_DISABLE_X;
303        else
304            executable_stack = EXSTACK_DEFAULT;
305    }
306
307    retval = -ENOEXEC;
308    if (stack_size == 0)
309        goto error;
310
311    if (elf_check_const_displacement(&interp_params.hdr))
312        interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
313
314    /* flush all traces of the currently running executable */
315    retval = flush_old_exec(bprm);
316    if (retval)
317        goto error;
318
319    /* there's now no turning back... the old userspace image is dead,
320     * defunct, deceased, etc. after this point we have to exit via
321     * error_kill */
322    set_personality(PER_LINUX_FDPIC);
323    if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
324        current->personality |= READ_IMPLIES_EXEC;
325
326    setup_new_exec(bprm);
327
328    set_binfmt(&elf_fdpic_format);
329
330    current->mm->start_code = 0;
331    current->mm->end_code = 0;
332    current->mm->start_stack = 0;
333    current->mm->start_data = 0;
334    current->mm->end_data = 0;
335    current->mm->context.exec_fdpic_loadmap = 0;
336    current->mm->context.interp_fdpic_loadmap = 0;
337
338    current->flags &= ~PF_FORKNOEXEC;
339
340#ifdef CONFIG_MMU
341    elf_fdpic_arch_lay_out_mm(&exec_params,
342                  &interp_params,
343                  &current->mm->start_stack,
344                  &current->mm->start_brk);
345
346    retval = setup_arg_pages(bprm, current->mm->start_stack,
347                 executable_stack);
348    if (retval < 0) {
349        send_sig(SIGKILL, current, 0);
350        goto error_kill;
351    }
352#endif
353
354    /* load the executable and interpreter into memory */
355    retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
356                    "executable");
357    if (retval < 0)
358        goto error_kill;
359
360    if (interpreter_name) {
361        retval = elf_fdpic_map_file(&interp_params, interpreter,
362                        current->mm, "interpreter");
363        if (retval < 0) {
364            printk(KERN_ERR "Unable to load interpreter\n");
365            goto error_kill;
366        }
367
368        allow_write_access(interpreter);
369        fput(interpreter);
370        interpreter = NULL;
371    }
372
373#ifdef CONFIG_MMU
374    if (!current->mm->start_brk)
375        current->mm->start_brk = current->mm->end_data;
376
377    current->mm->brk = current->mm->start_brk =
378        PAGE_ALIGN(current->mm->start_brk);
379
380#else
381    /* create a stack and brk area big enough for everyone
382     * - the brk heap starts at the bottom and works up
383     * - the stack starts at the top and works down
384     */
385    stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
386    if (stack_size < PAGE_SIZE * 2)
387        stack_size = PAGE_SIZE * 2;
388
389    stack_prot = PROT_READ | PROT_WRITE;
390    if (executable_stack == EXSTACK_ENABLE_X ||
391        (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
392        stack_prot |= PROT_EXEC;
393
394    down_write(&current->mm->mmap_sem);
395    current->mm->start_brk = do_mmap(NULL, 0, stack_size, stack_prot,
396                     MAP_PRIVATE | MAP_ANONYMOUS |
397                     MAP_UNINITIALIZED | MAP_GROWSDOWN,
398                     0);
399
400    if (IS_ERR_VALUE(current->mm->start_brk)) {
401        up_write(&current->mm->mmap_sem);
402        retval = current->mm->start_brk;
403        current->mm->start_brk = 0;
404        goto error_kill;
405    }
406
407    up_write(&current->mm->mmap_sem);
408
409    current->mm->brk = current->mm->start_brk;
410    current->mm->context.end_brk = current->mm->start_brk;
411    current->mm->context.end_brk +=
412        (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
413    current->mm->start_stack = current->mm->start_brk + stack_size;
414#endif
415
416    install_exec_creds(bprm);
417    current->flags &= ~PF_FORKNOEXEC;
418    if (create_elf_fdpic_tables(bprm, current->mm,
419                    &exec_params, &interp_params) < 0)
420        goto error_kill;
421
422    kdebug("- start_code %lx", current->mm->start_code);
423    kdebug("- end_code %lx", current->mm->end_code);
424    kdebug("- start_data %lx", current->mm->start_data);
425    kdebug("- end_data %lx", current->mm->end_data);
426    kdebug("- start_brk %lx", current->mm->start_brk);
427    kdebug("- brk %lx", current->mm->brk);
428    kdebug("- start_stack %lx", current->mm->start_stack);
429
430#ifdef ELF_FDPIC_PLAT_INIT
431    /*
432     * The ABI may specify that certain registers be set up in special
433     * ways (on i386 %edx is the address of a DT_FINI function, for
434     * example. This macro performs whatever initialization to
435     * the regs structure is required.
436     */
437    dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
438    ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
439                dynaddr);
440#endif
441
442    /* everything is now ready... get the userspace context ready to roll */
443    entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
444    start_thread(regs, entryaddr, current->mm->start_stack);
445
446    retval = 0;
447
448error:
449    if (interpreter) {
450        allow_write_access(interpreter);
451        fput(interpreter);
452    }
453    kfree(interpreter_name);
454    kfree(exec_params.phdrs);
455    kfree(exec_params.loadmap);
456    kfree(interp_params.phdrs);
457    kfree(interp_params.loadmap);
458    return retval;
459
460    /* unrecoverable error - kill the process */
461error_kill:
462    send_sig(SIGSEGV, current, 0);
463    goto error;
464
465}
466
467/*****************************************************************************/
468
469#ifndef ELF_BASE_PLATFORM
470/*
471 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
472 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
473 * will be copied to the user stack in the same manner as AT_PLATFORM.
474 */
475#define ELF_BASE_PLATFORM NULL
476#endif
477
478/*
479 * present useful information to the program by shovelling it onto the new
480 * process's stack
481 */
482static int create_elf_fdpic_tables(struct linux_binprm *bprm,
483                   struct mm_struct *mm,
484                   struct elf_fdpic_params *exec_params,
485                   struct elf_fdpic_params *interp_params)
486{
487    const struct cred *cred = current_cred();
488    unsigned long sp, csp, nitems;
489    elf_caddr_t __user *argv, *envp;
490    size_t platform_len = 0, len;
491    char *k_platform, *k_base_platform;
492    char __user *u_platform, *u_base_platform, *p;
493    long hwcap;
494    int loop;
495    int nr; /* reset for each csp adjustment */
496
497#ifdef CONFIG_MMU
498    /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
499     * by the processes running on the same package. One thing we can do is
500     * to shuffle the initial stack for them, so we give the architecture
501     * an opportunity to do so here.
502     */
503    sp = arch_align_stack(bprm->p);
504#else
505    sp = mm->start_stack;
506
507    /* stack the program arguments and environment */
508    if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
509        return -EFAULT;
510#endif
511
512    hwcap = ELF_HWCAP;
513
514    /*
515     * If this architecture has a platform capability string, copy it
516     * to userspace. In some cases (Sparc), this info is impossible
517     * for userspace to get any other way, in others (i386) it is
518     * merely difficult.
519     */
520    k_platform = ELF_PLATFORM;
521    u_platform = NULL;
522
523    if (k_platform) {
524        platform_len = strlen(k_platform) + 1;
525        sp -= platform_len;
526        u_platform = (char __user *) sp;
527        if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
528            return -EFAULT;
529    }
530
531    /*
532     * If this architecture has a "base" platform capability
533     * string, copy it to userspace.
534     */
535    k_base_platform = ELF_BASE_PLATFORM;
536    u_base_platform = NULL;
537
538    if (k_base_platform) {
539        platform_len = strlen(k_base_platform) + 1;
540        sp -= platform_len;
541        u_base_platform = (char __user *) sp;
542        if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
543            return -EFAULT;
544    }
545
546    sp &= ~7UL;
547
548    /* stack the load map(s) */
549    len = sizeof(struct elf32_fdpic_loadmap);
550    len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
551    sp = (sp - len) & ~7UL;
552    exec_params->map_addr = sp;
553
554    if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
555        return -EFAULT;
556
557    current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
558
559    if (interp_params->loadmap) {
560        len = sizeof(struct elf32_fdpic_loadmap);
561        len += sizeof(struct elf32_fdpic_loadseg) *
562            interp_params->loadmap->nsegs;
563        sp = (sp - len) & ~7UL;
564        interp_params->map_addr = sp;
565
566        if (copy_to_user((void __user *) sp, interp_params->loadmap,
567                 len) != 0)
568            return -EFAULT;
569
570        current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
571    }
572
573    /* force 16 byte _final_ alignment here for generality */
574#define DLINFO_ITEMS 15
575
576    nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
577        (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
578
579    if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
580        nitems++;
581
582    csp = sp;
583    sp -= nitems * 2 * sizeof(unsigned long);
584    sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
585    sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
586    sp -= 1 * sizeof(unsigned long); /* argc */
587
588    csp -= sp & 15UL;
589    sp -= sp & 15UL;
590
591    /* put the ELF interpreter info on the stack */
592#define NEW_AUX_ENT(id, val) \
593    do { \
594        struct { unsigned long _id, _val; } __user *ent; \
595                                    \
596        ent = (void __user *) csp; \
597        __put_user((id), &ent[nr]._id); \
598        __put_user((val), &ent[nr]._val); \
599        nr++; \
600    } while (0)
601
602    nr = 0;
603    csp -= 2 * sizeof(unsigned long);
604    NEW_AUX_ENT(AT_NULL, 0);
605    if (k_platform) {
606        nr = 0;
607        csp -= 2 * sizeof(unsigned long);
608        NEW_AUX_ENT(AT_PLATFORM,
609                (elf_addr_t) (unsigned long) u_platform);
610    }
611
612    if (k_base_platform) {
613        nr = 0;
614        csp -= 2 * sizeof(unsigned long);
615        NEW_AUX_ENT(AT_BASE_PLATFORM,
616                (elf_addr_t) (unsigned long) u_base_platform);
617    }
618
619    if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
620        nr = 0;
621        csp -= 2 * sizeof(unsigned long);
622        NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
623    }
624
625    nr = 0;
626    csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
627    NEW_AUX_ENT(AT_HWCAP, hwcap);
628    NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
629    NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
630    NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
631    NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
632    NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum);
633    NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr);
634    NEW_AUX_ENT(AT_FLAGS, 0);
635    NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr);
636    NEW_AUX_ENT(AT_UID, (elf_addr_t) cred->uid);
637    NEW_AUX_ENT(AT_EUID, (elf_addr_t) cred->euid);
638    NEW_AUX_ENT(AT_GID, (elf_addr_t) cred->gid);
639    NEW_AUX_ENT(AT_EGID, (elf_addr_t) cred->egid);
640    NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
641    NEW_AUX_ENT(AT_EXECFN, bprm->exec);
642
643#ifdef ARCH_DLINFO
644    nr = 0;
645    csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
646
647    /* ARCH_DLINFO must come last so platform specific code can enforce
648     * special alignment requirements on the AUXV if necessary (eg. PPC).
649     */
650    ARCH_DLINFO;
651#endif
652#undef NEW_AUX_ENT
653
654    /* allocate room for argv[] and envv[] */
655    csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
656    envp = (elf_caddr_t __user *) csp;
657    csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
658    argv = (elf_caddr_t __user *) csp;
659
660    /* stack argc */
661    csp -= sizeof(unsigned long);
662    __put_user(bprm->argc, (unsigned long __user *) csp);
663
664    BUG_ON(csp != sp);
665
666    /* fill in the argv[] array */
667#ifdef CONFIG_MMU
668    current->mm->arg_start = bprm->p;
669#else
670    current->mm->arg_start = current->mm->start_stack -
671        (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
672#endif
673
674    p = (char __user *) current->mm->arg_start;
675    for (loop = bprm->argc; loop > 0; loop--) {
676        __put_user((elf_caddr_t) p, argv++);
677        len = strnlen_user(p, MAX_ARG_STRLEN);
678        if (!len || len > MAX_ARG_STRLEN)
679            return -EINVAL;
680        p += len;
681    }
682    __put_user(NULL, argv);
683    current->mm->arg_end = (unsigned long) p;
684
685    /* fill in the envv[] array */
686    current->mm->env_start = (unsigned long) p;
687    for (loop = bprm->envc; loop > 0; loop--) {
688        __put_user((elf_caddr_t)(unsigned long) p, envp++);
689        len = strnlen_user(p, MAX_ARG_STRLEN);
690        if (!len || len > MAX_ARG_STRLEN)
691            return -EINVAL;
692        p += len;
693    }
694    __put_user(NULL, envp);
695    current->mm->env_end = (unsigned long) p;
696
697    mm->start_stack = (unsigned long) sp;
698    return 0;
699}
700
701/*****************************************************************************/
702/*
703 * transfer the program arguments and environment from the holding pages onto
704 * the stack
705 */
706#ifndef CONFIG_MMU
707static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm,
708                        unsigned long *_sp)
709{
710    unsigned long index, stop, sp;
711    char *src;
712    int ret = 0;
713
714    stop = bprm->p >> PAGE_SHIFT;
715    sp = *_sp;
716
717    for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
718        src = kmap(bprm->page[index]);
719        sp -= PAGE_SIZE;
720        if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
721            ret = -EFAULT;
722        kunmap(bprm->page[index]);
723        if (ret < 0)
724            goto out;
725    }
726
727    *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
728
729out:
730    return ret;
731}
732#endif
733
734/*****************************************************************************/
735/*
736 * load the appropriate binary image (executable or interpreter) into memory
737 * - we assume no MMU is available
738 * - if no other PIC bits are set in params->hdr->e_flags
739 * - we assume that the LOADable segments in the binary are independently relocatable
740 * - we assume R/O executable segments are shareable
741 * - else
742 * - we assume the loadable parts of the image to require fixed displacement
743 * - the image is not shareable
744 */
745static int elf_fdpic_map_file(struct elf_fdpic_params *params,
746                  struct file *file,
747                  struct mm_struct *mm,
748                  const char *what)
749{
750    struct elf32_fdpic_loadmap *loadmap;
751#ifdef CONFIG_MMU
752    struct elf32_fdpic_loadseg *mseg;
753#endif
754    struct elf32_fdpic_loadseg *seg;
755    struct elf32_phdr *phdr;
756    unsigned long load_addr, stop;
757    unsigned nloads, tmp;
758    size_t size;
759    int loop, ret;
760
761    /* allocate a load map table */
762    nloads = 0;
763    for (loop = 0; loop < params->hdr.e_phnum; loop++)
764        if (params->phdrs[loop].p_type == PT_LOAD)
765            nloads++;
766
767    if (nloads == 0)
768        return -ELIBBAD;
769
770    size = sizeof(*loadmap) + nloads * sizeof(*seg);
771    loadmap = kzalloc(size, GFP_KERNEL);
772    if (!loadmap)
773        return -ENOMEM;
774
775    params->loadmap = loadmap;
776
777    loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
778    loadmap->nsegs = nloads;
779
780    load_addr = params->load_addr;
781    seg = loadmap->segs;
782
783    /* map the requested LOADs into the memory space */
784    switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
785    case ELF_FDPIC_FLAG_CONSTDISP:
786    case ELF_FDPIC_FLAG_CONTIGUOUS:
787#ifndef CONFIG_MMU
788        ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
789        if (ret < 0)
790            return ret;
791        break;
792#endif
793    default:
794        ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
795        if (ret < 0)
796            return ret;
797        break;
798    }
799
800    /* map the entry point */
801    if (params->hdr.e_entry) {
802        seg = loadmap->segs;
803        for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
804            if (params->hdr.e_entry >= seg->p_vaddr &&
805                params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
806                params->entry_addr =
807                    (params->hdr.e_entry - seg->p_vaddr) +
808                    seg->addr;
809                break;
810            }
811        }
812    }
813
814    /* determine where the program header table has wound up if mapped */
815    stop = params->hdr.e_phoff;
816    stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
817    phdr = params->phdrs;
818
819    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
820        if (phdr->p_type != PT_LOAD)
821            continue;
822
823        if (phdr->p_offset > params->hdr.e_phoff ||
824            phdr->p_offset + phdr->p_filesz < stop)
825            continue;
826
827        seg = loadmap->segs;
828        for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
829            if (phdr->p_vaddr >= seg->p_vaddr &&
830                phdr->p_vaddr + phdr->p_filesz <=
831                seg->p_vaddr + seg->p_memsz) {
832                params->ph_addr =
833                    (phdr->p_vaddr - seg->p_vaddr) +
834                    seg->addr +
835                    params->hdr.e_phoff - phdr->p_offset;
836                break;
837            }
838        }
839        break;
840    }
841
842    /* determine where the dynamic section has wound up if there is one */
843    phdr = params->phdrs;
844    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
845        if (phdr->p_type != PT_DYNAMIC)
846            continue;
847
848        seg = loadmap->segs;
849        for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
850            if (phdr->p_vaddr >= seg->p_vaddr &&
851                phdr->p_vaddr + phdr->p_memsz <=
852                seg->p_vaddr + seg->p_memsz) {
853                params->dynamic_addr =
854                    (phdr->p_vaddr - seg->p_vaddr) +
855                    seg->addr;
856
857                /* check the dynamic section contains at least
858                 * one item, and that the last item is a NULL
859                 * entry */
860                if (phdr->p_memsz == 0 ||
861                    phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
862                    goto dynamic_error;
863
864                tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
865                if (((Elf32_Dyn *)
866                     params->dynamic_addr)[tmp - 1].d_tag != 0)
867                    goto dynamic_error;
868                break;
869            }
870        }
871        break;
872    }
873
874    /* now elide adjacent segments in the load map on MMU linux
875     * - on uClinux the holes between may actually be filled with system
876     * stuff or stuff from other processes
877     */
878#ifdef CONFIG_MMU
879    nloads = loadmap->nsegs;
880    mseg = loadmap->segs;
881    seg = mseg + 1;
882    for (loop = 1; loop < nloads; loop++) {
883        /* see if we have a candidate for merging */
884        if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
885            load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
886            if (load_addr == (seg->addr & PAGE_MASK)) {
887                mseg->p_memsz +=
888                    load_addr -
889                    (mseg->addr + mseg->p_memsz);
890                mseg->p_memsz += seg->addr & ~PAGE_MASK;
891                mseg->p_memsz += seg->p_memsz;
892                loadmap->nsegs--;
893                continue;
894            }
895        }
896
897        mseg++;
898        if (mseg != seg)
899            *mseg = *seg;
900    }
901#endif
902
903    kdebug("Mapped Object [%s]:", what);
904    kdebug("- elfhdr : %lx", params->elfhdr_addr);
905    kdebug("- entry : %lx", params->entry_addr);
906    kdebug("- PHDR[] : %lx", params->ph_addr);
907    kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
908    seg = loadmap->segs;
909    for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
910        kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
911               loop,
912               seg->addr, seg->addr + seg->p_memsz - 1,
913               seg->p_vaddr, seg->p_memsz);
914
915    return 0;
916
917dynamic_error:
918    printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
919           what, file->f_path.dentry->d_inode->i_ino);
920    return -ELIBBAD;
921}
922
923/*****************************************************************************/
924/*
925 * map a file with constant displacement under uClinux
926 */
927#ifndef CONFIG_MMU
928static int elf_fdpic_map_file_constdisp_on_uclinux(
929    struct elf_fdpic_params *params,
930    struct file *file,
931    struct mm_struct *mm)
932{
933    struct elf32_fdpic_loadseg *seg;
934    struct elf32_phdr *phdr;
935    unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
936    loff_t fpos;
937    int loop, ret;
938
939    load_addr = params->load_addr;
940    seg = params->loadmap->segs;
941
942    /* determine the bounds of the contiguous overall allocation we must
943     * make */
944    phdr = params->phdrs;
945    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
946        if (params->phdrs[loop].p_type != PT_LOAD)
947            continue;
948
949        if (base > phdr->p_vaddr)
950            base = phdr->p_vaddr;
951        if (top < phdr->p_vaddr + phdr->p_memsz)
952            top = phdr->p_vaddr + phdr->p_memsz;
953    }
954
955    /* allocate one big anon block for everything */
956    mflags = MAP_PRIVATE;
957    if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
958        mflags |= MAP_EXECUTABLE;
959
960    down_write(&mm->mmap_sem);
961    maddr = do_mmap(NULL, load_addr, top - base,
962            PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
963    up_write(&mm->mmap_sem);
964    if (IS_ERR_VALUE(maddr))
965        return (int) maddr;
966
967    if (load_addr != 0)
968        load_addr += PAGE_ALIGN(top - base);
969
970    /* and then load the file segments into it */
971    phdr = params->phdrs;
972    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
973        if (params->phdrs[loop].p_type != PT_LOAD)
974            continue;
975
976        fpos = phdr->p_offset;
977
978        seg->addr = maddr + (phdr->p_vaddr - base);
979        seg->p_vaddr = phdr->p_vaddr;
980        seg->p_memsz = phdr->p_memsz;
981
982        ret = file->f_op->read(file, (void *) seg->addr,
983                       phdr->p_filesz, &fpos);
984        if (ret < 0)
985            return ret;
986
987        /* map the ELF header address if in this segment */
988        if (phdr->p_offset == 0)
989            params->elfhdr_addr = seg->addr;
990
991        /* clear any space allocated but not loaded */
992        if (phdr->p_filesz < phdr->p_memsz) {
993            ret = clear_user((void *) (seg->addr + phdr->p_filesz),
994                     phdr->p_memsz - phdr->p_filesz);
995            if (ret)
996                return ret;
997        }
998
999        if (mm) {
1000            if (phdr->p_flags & PF_X) {
1001                if (!mm->start_code) {
1002                    mm->start_code = seg->addr;
1003                    mm->end_code = seg->addr +
1004                        phdr->p_memsz;
1005                }
1006            } else if (!mm->start_data) {
1007                mm->start_data = seg->addr;
1008#ifndef CONFIG_MMU
1009                mm->end_data = seg->addr + phdr->p_memsz;
1010#endif
1011            }
1012
1013#ifdef CONFIG_MMU
1014            if (seg->addr + phdr->p_memsz > mm->end_data)
1015                mm->end_data = seg->addr + phdr->p_memsz;
1016#endif
1017        }
1018
1019        seg++;
1020    }
1021
1022    return 0;
1023}
1024#endif
1025
1026/*****************************************************************************/
1027/*
1028 * map a binary by direct mmap() of the individual PT_LOAD segments
1029 */
1030static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
1031                         struct file *file,
1032                         struct mm_struct *mm)
1033{
1034    struct elf32_fdpic_loadseg *seg;
1035    struct elf32_phdr *phdr;
1036    unsigned long load_addr, delta_vaddr;
1037    int loop, dvset, ret;
1038
1039    load_addr = params->load_addr;
1040    delta_vaddr = 0;
1041    dvset = 0;
1042
1043    seg = params->loadmap->segs;
1044
1045    /* deal with each load segment separately */
1046    phdr = params->phdrs;
1047    for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1048        unsigned long maddr, disp, excess, excess1;
1049        int prot = 0, flags;
1050
1051        if (phdr->p_type != PT_LOAD)
1052            continue;
1053
1054        kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1055               (unsigned long) phdr->p_vaddr,
1056               (unsigned long) phdr->p_offset,
1057               (unsigned long) phdr->p_filesz,
1058               (unsigned long) phdr->p_memsz);
1059
1060        /* determine the mapping parameters */
1061        if (phdr->p_flags & PF_R) prot |= PROT_READ;
1062        if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1063        if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1064
1065        flags = MAP_PRIVATE | MAP_DENYWRITE;
1066        if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1067            flags |= MAP_EXECUTABLE;
1068
1069        maddr = 0;
1070
1071        switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1072        case ELF_FDPIC_FLAG_INDEPENDENT:
1073            /* PT_LOADs are independently locatable */
1074            break;
1075
1076        case ELF_FDPIC_FLAG_HONOURVADDR:
1077            /* the specified virtual address must be honoured */
1078            maddr = phdr->p_vaddr;
1079            flags |= MAP_FIXED;
1080            break;
1081
1082        case ELF_FDPIC_FLAG_CONSTDISP:
1083            /* constant displacement
1084             * - can be mapped anywhere, but must be mapped as a
1085             * unit
1086             */
1087            if (!dvset) {
1088                maddr = load_addr;
1089                delta_vaddr = phdr->p_vaddr;
1090                dvset = 1;
1091            } else {
1092                maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1093                flags |= MAP_FIXED;
1094            }
1095            break;
1096
1097        case ELF_FDPIC_FLAG_CONTIGUOUS:
1098            /* contiguity handled later */
1099            break;
1100
1101        default:
1102            BUG();
1103        }
1104
1105        maddr &= PAGE_MASK;
1106
1107        /* create the mapping */
1108        disp = phdr->p_vaddr & ~PAGE_MASK;
1109        down_write(&mm->mmap_sem);
1110        maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1111                phdr->p_offset - disp);
1112        up_write(&mm->mmap_sem);
1113
1114        kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1115               loop, phdr->p_memsz + disp, prot, flags,
1116               phdr->p_offset - disp, maddr);
1117
1118        if (IS_ERR_VALUE(maddr))
1119            return (int) maddr;
1120
1121        if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1122            ELF_FDPIC_FLAG_CONTIGUOUS)
1123            load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1124
1125        seg->addr = maddr + disp;
1126        seg->p_vaddr = phdr->p_vaddr;
1127        seg->p_memsz = phdr->p_memsz;
1128
1129        /* map the ELF header address if in this segment */
1130        if (phdr->p_offset == 0)
1131            params->elfhdr_addr = seg->addr;
1132
1133        /* clear the bit between beginning of mapping and beginning of
1134         * PT_LOAD */
1135        if (prot & PROT_WRITE && disp > 0) {
1136            kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1137            ret = clear_user((void __user *) maddr, disp);
1138            if (ret)
1139                return ret;
1140            maddr += disp;
1141        }
1142
1143        /* clear any space allocated but not loaded
1144         * - on uClinux we can just clear the lot
1145         * - on MMU linux we'll get a SIGBUS beyond the last page
1146         * extant in the file
1147         */
1148        excess = phdr->p_memsz - phdr->p_filesz;
1149        excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1150
1151#ifdef CONFIG_MMU
1152        if (excess > excess1) {
1153            unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1154            unsigned long xmaddr;
1155
1156            flags |= MAP_FIXED | MAP_ANONYMOUS;
1157            down_write(&mm->mmap_sem);
1158            xmaddr = do_mmap(NULL, xaddr, excess - excess1,
1159                     prot, flags, 0);
1160            up_write(&mm->mmap_sem);
1161
1162            kdebug("mmap[%d] <anon>"
1163                   " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1164                   loop, xaddr, excess - excess1, prot, flags,
1165                   xmaddr);
1166
1167            if (xmaddr != xaddr)
1168                return -ENOMEM;
1169        }
1170
1171        if (prot & PROT_WRITE && excess1 > 0) {
1172            kdebug("clear[%d] ad=%lx sz=%lx",
1173                   loop, maddr + phdr->p_filesz, excess1);
1174            ret = clear_user((void __user *) maddr + phdr->p_filesz,
1175                     excess1);
1176            if (ret)
1177                return ret;
1178        }
1179
1180#else
1181        if (excess > 0) {
1182            kdebug("clear[%d] ad=%lx sz=%lx",
1183                   loop, maddr + phdr->p_filesz, excess);
1184            ret = clear_user((void *) maddr + phdr->p_filesz, excess);
1185            if (ret)
1186                return ret;
1187        }
1188#endif
1189
1190        if (mm) {
1191            if (phdr->p_flags & PF_X) {
1192                if (!mm->start_code) {
1193                    mm->start_code = maddr;
1194                    mm->end_code = maddr + phdr->p_memsz;
1195                }
1196            } else if (!mm->start_data) {
1197                mm->start_data = maddr;
1198                mm->end_data = maddr + phdr->p_memsz;
1199            }
1200        }
1201
1202        seg++;
1203    }
1204
1205    return 0;
1206}
1207
1208/*****************************************************************************/
1209/*
1210 * ELF-FDPIC core dumper
1211 *
1212 * Modelled on fs/exec.c:aout_core_dump()
1213 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1214 *
1215 * Modelled on fs/binfmt_elf.c core dumper
1216 */
1217#ifdef CONFIG_ELF_CORE
1218
1219/*
1220 * Decide whether a segment is worth dumping; default is yes to be
1221 * sure (missing info is worse than too much; etc).
1222 * Personally I'd include everything, and use the coredump limit...
1223 *
1224 * I think we should skip something. But I am not sure how. H.J.
1225 */
1226static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1227{
1228    int dump_ok;
1229
1230    /* Do not dump I/O mapped devices or special mappings */
1231    if (vma->vm_flags & (VM_IO | VM_RESERVED)) {
1232        kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1233        return 0;
1234    }
1235
1236    /* If we may not read the contents, don't allow us to dump
1237     * them either. "dump_write()" can't handle it anyway.
1238     */
1239    if (!(vma->vm_flags & VM_READ)) {
1240        kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1241        return 0;
1242    }
1243
1244    /* By default, dump shared memory if mapped from an anonymous file. */
1245    if (vma->vm_flags & VM_SHARED) {
1246        if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0) {
1247            dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
1248            kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1249                   vma->vm_flags, dump_ok ? "yes" : "no");
1250            return dump_ok;
1251        }
1252
1253        dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
1254        kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1255               vma->vm_flags, dump_ok ? "yes" : "no");
1256        return dump_ok;
1257    }
1258
1259#ifdef CONFIG_MMU
1260    /* By default, if it hasn't been written to, don't write it out */
1261    if (!vma->anon_vma) {
1262        dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1263        kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1264               vma->vm_flags, dump_ok ? "yes" : "no");
1265        return dump_ok;
1266    }
1267#endif
1268
1269    dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1270    kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1271           dump_ok ? "yes" : "no");
1272    return dump_ok;
1273}
1274
1275/* An ELF note in memory */
1276struct memelfnote
1277{
1278    const char *name;
1279    int type;
1280    unsigned int datasz;
1281    void *data;
1282};
1283
1284static int notesize(struct memelfnote *en)
1285{
1286    int sz;
1287
1288    sz = sizeof(struct elf_note);
1289    sz += roundup(strlen(en->name) + 1, 4);
1290    sz += roundup(en->datasz, 4);
1291
1292    return sz;
1293}
1294
1295/* #define DEBUG */
1296
1297#define DUMP_WRITE(addr, nr, foffset) \
1298    do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
1299
1300static int alignfile(struct file *file, loff_t *foffset)
1301{
1302    static const char buf[4] = { 0, };
1303    DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
1304    return 1;
1305}
1306
1307static int writenote(struct memelfnote *men, struct file *file,
1308            loff_t *foffset)
1309{
1310    struct elf_note en;
1311    en.n_namesz = strlen(men->name) + 1;
1312    en.n_descsz = men->datasz;
1313    en.n_type = men->type;
1314
1315    DUMP_WRITE(&en, sizeof(en), foffset);
1316    DUMP_WRITE(men->name, en.n_namesz, foffset);
1317    if (!alignfile(file, foffset))
1318        return 0;
1319    DUMP_WRITE(men->data, men->datasz, foffset);
1320    if (!alignfile(file, foffset))
1321        return 0;
1322
1323    return 1;
1324}
1325#undef DUMP_WRITE
1326
1327static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1328{
1329    memcpy(elf->e_ident, ELFMAG, SELFMAG);
1330    elf->e_ident[EI_CLASS] = ELF_CLASS;
1331    elf->e_ident[EI_DATA] = ELF_DATA;
1332    elf->e_ident[EI_VERSION] = EV_CURRENT;
1333    elf->e_ident[EI_OSABI] = ELF_OSABI;
1334    memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1335
1336    elf->e_type = ET_CORE;
1337    elf->e_machine = ELF_ARCH;
1338    elf->e_version = EV_CURRENT;
1339    elf->e_entry = 0;
1340    elf->e_phoff = sizeof(struct elfhdr);
1341    elf->e_shoff = 0;
1342    elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1343    elf->e_ehsize = sizeof(struct elfhdr);
1344    elf->e_phentsize = sizeof(struct elf_phdr);
1345    elf->e_phnum = segs;
1346    elf->e_shentsize = 0;
1347    elf->e_shnum = 0;
1348    elf->e_shstrndx = 0;
1349    return;
1350}
1351
1352static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1353{
1354    phdr->p_type = PT_NOTE;
1355    phdr->p_offset = offset;
1356    phdr->p_vaddr = 0;
1357    phdr->p_paddr = 0;
1358    phdr->p_filesz = sz;
1359    phdr->p_memsz = 0;
1360    phdr->p_flags = 0;
1361    phdr->p_align = 0;
1362    return;
1363}
1364
1365static inline void fill_note(struct memelfnote *note, const char *name, int type,
1366        unsigned int sz, void *data)
1367{
1368    note->name = name;
1369    note->type = type;
1370    note->datasz = sz;
1371    note->data = data;
1372    return;
1373}
1374
1375/*
1376 * fill up all the fields in prstatus from the given task struct, except
1377 * registers which need to be filled up separately.
1378 */
1379static void fill_prstatus(struct elf_prstatus *prstatus,
1380              struct task_struct *p, long signr)
1381{
1382    prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1383    prstatus->pr_sigpend = p->pending.signal.sig[0];
1384    prstatus->pr_sighold = p->blocked.sig[0];
1385    rcu_read_lock();
1386    prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1387    rcu_read_unlock();
1388    prstatus->pr_pid = task_pid_vnr(p);
1389    prstatus->pr_pgrp = task_pgrp_vnr(p);
1390    prstatus->pr_sid = task_session_vnr(p);
1391    if (thread_group_leader(p)) {
1392        struct task_cputime cputime;
1393
1394        /*
1395         * This is the record for the group leader. It shows the
1396         * group-wide total, not its individual thread total.
1397         */
1398        thread_group_cputime(p, &cputime);
1399        cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1400        cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1401    } else {
1402        cputime_to_timeval(p->utime, &prstatus->pr_utime);
1403        cputime_to_timeval(p->stime, &prstatus->pr_stime);
1404    }
1405    cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1406    cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1407
1408    prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1409    prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1410}
1411
1412static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1413               struct mm_struct *mm)
1414{
1415    const struct cred *cred;
1416    unsigned int i, len;
1417
1418    /* first copy the parameters from user space */
1419    memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1420
1421    len = mm->arg_end - mm->arg_start;
1422    if (len >= ELF_PRARGSZ)
1423        len = ELF_PRARGSZ - 1;
1424    if (copy_from_user(&psinfo->pr_psargs,
1425                   (const char __user *) mm->arg_start, len))
1426        return -EFAULT;
1427    for (i = 0; i < len; i++)
1428        if (psinfo->pr_psargs[i] == 0)
1429            psinfo->pr_psargs[i] = ' ';
1430    psinfo->pr_psargs[len] = 0;
1431
1432    rcu_read_lock();
1433    psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1434    rcu_read_unlock();
1435    psinfo->pr_pid = task_pid_vnr(p);
1436    psinfo->pr_pgrp = task_pgrp_vnr(p);
1437    psinfo->pr_sid = task_session_vnr(p);
1438
1439    i = p->state ? ffz(~p->state) + 1 : 0;
1440    psinfo->pr_state = i;
1441    psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1442    psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1443    psinfo->pr_nice = task_nice(p);
1444    psinfo->pr_flag = p->flags;
1445    rcu_read_lock();
1446    cred = __task_cred(p);
1447    SET_UID(psinfo->pr_uid, cred->uid);
1448    SET_GID(psinfo->pr_gid, cred->gid);
1449    rcu_read_unlock();
1450    strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1451
1452    return 0;
1453}
1454
1455/* Here is the structure in which status of each thread is captured. */
1456struct elf_thread_status
1457{
1458    struct list_head list;
1459    struct elf_prstatus prstatus; /* NT_PRSTATUS */
1460    elf_fpregset_t fpu; /* NT_PRFPREG */
1461    struct task_struct *thread;
1462#ifdef ELF_CORE_COPY_XFPREGS
1463    elf_fpxregset_t xfpu; /* ELF_CORE_XFPREG_TYPE */
1464#endif
1465    struct memelfnote notes[3];
1466    int num_notes;
1467};
1468
1469/*
1470 * In order to add the specific thread information for the elf file format,
1471 * we need to keep a linked list of every thread's pr_status and then create
1472 * a single section for them in the final core file.
1473 */
1474static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1475{
1476    struct task_struct *p = t->thread;
1477    int sz = 0;
1478
1479    t->num_notes = 0;
1480
1481    fill_prstatus(&t->prstatus, p, signr);
1482    elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1483
1484    fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1485          &t->prstatus);
1486    t->num_notes++;
1487    sz += notesize(&t->notes[0]);
1488
1489    t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1490    if (t->prstatus.pr_fpvalid) {
1491        fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1492              &t->fpu);
1493        t->num_notes++;
1494        sz += notesize(&t->notes[1]);
1495    }
1496
1497#ifdef ELF_CORE_COPY_XFPREGS
1498    if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1499        fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1500              sizeof(t->xfpu), &t->xfpu);
1501        t->num_notes++;
1502        sz += notesize(&t->notes[2]);
1503    }
1504#endif
1505    return sz;
1506}
1507
1508static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1509                 elf_addr_t e_shoff, int segs)
1510{
1511    elf->e_shoff = e_shoff;
1512    elf->e_shentsize = sizeof(*shdr4extnum);
1513    elf->e_shnum = 1;
1514    elf->e_shstrndx = SHN_UNDEF;
1515
1516    memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1517
1518    shdr4extnum->sh_type = SHT_NULL;
1519    shdr4extnum->sh_size = elf->e_shnum;
1520    shdr4extnum->sh_link = elf->e_shstrndx;
1521    shdr4extnum->sh_info = segs;
1522}
1523
1524/*
1525 * dump the segments for an MMU process
1526 */
1527#ifdef CONFIG_MMU
1528static int elf_fdpic_dump_segments(struct file *file, size_t *size,
1529               unsigned long *limit, unsigned long mm_flags)
1530{
1531    struct vm_area_struct *vma;
1532    int err = 0;
1533
1534    for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1535        unsigned long addr;
1536
1537        if (!maydump(vma, mm_flags))
1538            continue;
1539
1540        for (addr = vma->vm_start; addr < vma->vm_end;
1541                            addr += PAGE_SIZE) {
1542            struct page *page = get_dump_page(addr);
1543            if (page) {
1544                void *kaddr = kmap(page);
1545                *size += PAGE_SIZE;
1546                if (*size > *limit)
1547                    err = -EFBIG;
1548                else if (!dump_write(file, kaddr, PAGE_SIZE))
1549                    err = -EIO;
1550                kunmap(page);
1551                page_cache_release(page);
1552            } else if (!dump_seek(file, PAGE_SIZE))
1553                err = -EFBIG;
1554            if (err)
1555                goto out;
1556        }
1557    }
1558out:
1559    return err;
1560}
1561#endif
1562
1563/*
1564 * dump the segments for a NOMMU process
1565 */
1566#ifndef CONFIG_MMU
1567static int elf_fdpic_dump_segments(struct file *file, size_t *size,
1568               unsigned long *limit, unsigned long mm_flags)
1569{
1570    struct vm_area_struct *vma;
1571
1572    for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1573        if (!maydump(vma, mm_flags))
1574            continue;
1575
1576        if ((*size += PAGE_SIZE) > *limit)
1577            return -EFBIG;
1578
1579        if (!dump_write(file, (void *) vma->vm_start,
1580                vma->vm_end - vma->vm_start))
1581            return -EIO;
1582    }
1583
1584    return 0;
1585}
1586#endif
1587
1588static size_t elf_core_vma_data_size(unsigned long mm_flags)
1589{
1590    struct vm_area_struct *vma;
1591    size_t size = 0;
1592
1593    for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1594        if (maydump(vma, mm_flags))
1595            size += vma->vm_end - vma->vm_start;
1596    return size;
1597}
1598
1599/*
1600 * Actual dumper
1601 *
1602 * This is a two-pass process; first we find the offsets of the bits,
1603 * and then they are actually written out. If we run out of core limit
1604 * we just truncate.
1605 */
1606static int elf_fdpic_core_dump(struct coredump_params *cprm)
1607{
1608#define NUM_NOTES 6
1609    int has_dumped = 0;
1610    mm_segment_t fs;
1611    int segs;
1612    size_t size = 0;
1613    int i;
1614    struct vm_area_struct *vma;
1615    struct elfhdr *elf = NULL;
1616    loff_t offset = 0, dataoff, foffset;
1617    int numnote;
1618    struct memelfnote *notes = NULL;
1619    struct elf_prstatus *prstatus = NULL; /* NT_PRSTATUS */
1620    struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
1621     LIST_HEAD(thread_list);
1622     struct list_head *t;
1623    elf_fpregset_t *fpu = NULL;
1624#ifdef ELF_CORE_COPY_XFPREGS
1625    elf_fpxregset_t *xfpu = NULL;
1626#endif
1627    int thread_status_size = 0;
1628    elf_addr_t *auxv;
1629    struct elf_phdr *phdr4note = NULL;
1630    struct elf_shdr *shdr4extnum = NULL;
1631    Elf_Half e_phnum;
1632    elf_addr_t e_shoff;
1633
1634    /*
1635     * We no longer stop all VM operations.
1636     *
1637     * This is because those proceses that could possibly change map_count
1638     * or the mmap / vma pages are now blocked in do_exit on current
1639     * finishing this core dump.
1640     *
1641     * Only ptrace can touch these memory addresses, but it doesn't change
1642     * the map_count or the pages allocated. So no possibility of crashing
1643     * exists while dumping the mm->vm_next areas to the core file.
1644     */
1645
1646    /* alloc memory for large data structures: too large to be on stack */
1647    elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1648    if (!elf)
1649        goto cleanup;
1650    prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1651    if (!prstatus)
1652        goto cleanup;
1653    psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1654    if (!psinfo)
1655        goto cleanup;
1656    notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
1657    if (!notes)
1658        goto cleanup;
1659    fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1660    if (!fpu)
1661        goto cleanup;
1662#ifdef ELF_CORE_COPY_XFPREGS
1663    xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1664    if (!xfpu)
1665        goto cleanup;
1666#endif
1667
1668    if (cprm->signr) {
1669        struct core_thread *ct;
1670        struct elf_thread_status *tmp;
1671
1672        for (ct = current->mm->core_state->dumper.next;
1673                        ct; ct = ct->next) {
1674            tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1675            if (!tmp)
1676                goto cleanup;
1677
1678            tmp->thread = ct->task;
1679            list_add(&tmp->list, &thread_list);
1680        }
1681
1682        list_for_each(t, &thread_list) {
1683            struct elf_thread_status *tmp;
1684            int sz;
1685
1686            tmp = list_entry(t, struct elf_thread_status, list);
1687            sz = elf_dump_thread_status(cprm->signr, tmp);
1688            thread_status_size += sz;
1689        }
1690    }
1691
1692    /* now collect the dump for the current */
1693    fill_prstatus(prstatus, current, cprm->signr);
1694    elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1695
1696    segs = current->mm->map_count;
1697    segs += elf_core_extra_phdrs();
1698
1699    /* for notes section */
1700    segs++;
1701
1702    /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1703     * this, kernel supports extended numbering. Have a look at
1704     * include/linux/elf.h for further information. */
1705    e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1706
1707    /* Set up header */
1708    fill_elf_fdpic_header(elf, e_phnum);
1709
1710    has_dumped = 1;
1711    current->flags |= PF_DUMPCORE;
1712
1713    /*
1714     * Set up the notes in similar form to SVR4 core dumps made
1715     * with info from their /proc.
1716     */
1717
1718    fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1719    fill_psinfo(psinfo, current->group_leader, current->mm);
1720    fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1721
1722    numnote = 2;
1723
1724    auxv = (elf_addr_t *) current->mm->saved_auxv;
1725
1726    i = 0;
1727    do
1728        i += 2;
1729    while (auxv[i - 2] != AT_NULL);
1730    fill_note(&notes[numnote++], "CORE", NT_AUXV,
1731          i * sizeof(elf_addr_t), auxv);
1732
1733      /* Try to dump the FPU. */
1734    if ((prstatus->pr_fpvalid =
1735         elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1736        fill_note(notes + numnote++,
1737              "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1738#ifdef ELF_CORE_COPY_XFPREGS
1739    if (elf_core_copy_task_xfpregs(current, xfpu))
1740        fill_note(notes + numnote++,
1741              "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1742#endif
1743
1744    fs = get_fs();
1745    set_fs(KERNEL_DS);
1746
1747    offset += sizeof(*elf); /* Elf header */
1748    offset += segs * sizeof(struct elf_phdr); /* Program headers */
1749    foffset = offset;
1750
1751    /* Write notes phdr entry */
1752    {
1753        int sz = 0;
1754
1755        for (i = 0; i < numnote; i++)
1756            sz += notesize(notes + i);
1757
1758        sz += thread_status_size;
1759
1760        phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1761        if (!phdr4note)
1762            goto end_coredump;
1763
1764        fill_elf_note_phdr(phdr4note, sz, offset);
1765        offset += sz;
1766    }
1767
1768    /* Page-align dumped data */
1769    dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1770
1771    offset += elf_core_vma_data_size(cprm->mm_flags);
1772    offset += elf_core_extra_data_size();
1773    e_shoff = offset;
1774
1775    if (e_phnum == PN_XNUM) {
1776        shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1777        if (!shdr4extnum)
1778            goto end_coredump;
1779        fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1780    }
1781
1782    offset = dataoff;
1783
1784    size += sizeof(*elf);
1785    if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
1786        goto end_coredump;
1787
1788    size += sizeof(*phdr4note);
1789    if (size > cprm->limit
1790        || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note)))
1791        goto end_coredump;
1792
1793    /* write program headers for segments dump */
1794    for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1795        struct elf_phdr phdr;
1796        size_t sz;
1797
1798        sz = vma->vm_end - vma->vm_start;
1799
1800        phdr.p_type = PT_LOAD;
1801        phdr.p_offset = offset;
1802        phdr.p_vaddr = vma->vm_start;
1803        phdr.p_paddr = 0;
1804        phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1805        phdr.p_memsz = sz;
1806        offset += phdr.p_filesz;
1807        phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1808        if (vma->vm_flags & VM_WRITE)
1809            phdr.p_flags |= PF_W;
1810        if (vma->vm_flags & VM_EXEC)
1811            phdr.p_flags |= PF_X;
1812        phdr.p_align = ELF_EXEC_PAGESIZE;
1813
1814        size += sizeof(phdr);
1815        if (size > cprm->limit
1816            || !dump_write(cprm->file, &phdr, sizeof(phdr)))
1817            goto end_coredump;
1818    }
1819
1820    if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
1821        goto end_coredump;
1822
1823     /* write out the notes section */
1824    for (i = 0; i < numnote; i++)
1825        if (!writenote(notes + i, cprm->file, &foffset))
1826            goto end_coredump;
1827
1828    /* write out the thread status notes section */
1829    list_for_each(t, &thread_list) {
1830        struct elf_thread_status *tmp =
1831                list_entry(t, struct elf_thread_status, list);
1832
1833        for (i = 0; i < tmp->num_notes; i++)
1834            if (!writenote(&tmp->notes[i], cprm->file, &foffset))
1835                goto end_coredump;
1836    }
1837
1838    if (!dump_seek(cprm->file, dataoff - foffset))
1839        goto end_coredump;
1840
1841    if (elf_fdpic_dump_segments(cprm->file, &size, &cprm->limit,
1842                    cprm->mm_flags) < 0)
1843        goto end_coredump;
1844
1845    if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
1846        goto end_coredump;
1847
1848    if (e_phnum == PN_XNUM) {
1849        size += sizeof(*shdr4extnum);
1850        if (size > cprm->limit
1851            || !dump_write(cprm->file, shdr4extnum,
1852                   sizeof(*shdr4extnum)))
1853            goto end_coredump;
1854    }
1855
1856    if (cprm->file->f_pos != offset) {
1857        /* Sanity check */
1858        printk(KERN_WARNING
1859               "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1860               cprm->file->f_pos, offset);
1861    }
1862
1863end_coredump:
1864    set_fs(fs);
1865
1866cleanup:
1867    while (!list_empty(&thread_list)) {
1868        struct list_head *tmp = thread_list.next;
1869        list_del(tmp);
1870        kfree(list_entry(tmp, struct elf_thread_status, list));
1871    }
1872    kfree(phdr4note);
1873    kfree(elf);
1874    kfree(prstatus);
1875    kfree(psinfo);
1876    kfree(notes);
1877    kfree(fpu);
1878#ifdef ELF_CORE_COPY_XFPREGS
1879    kfree(xfpu);
1880#endif
1881    return has_dumped;
1882#undef NUM_NOTES
1883}
1884
1885#endif /* CONFIG_ELF_CORE */
1886

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