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Linux/fs/binfmt_elf.c

  1 /*
  2  * linux/fs/binfmt_elf.c
  3  *
  4  * These are the functions used to load ELF format executables as used
  5  * on SVr4 machines.  Information on the format may be found in the book
  6  * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
  7  * Tools".
  8  *
  9  * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 10  */
 11 
 12 #include <linux/module.h>
 13 #include <linux/kernel.h>
 14 #include <linux/fs.h>
 15 #include <linux/mm.h>
 16 #include <linux/mman.h>
 17 #include <linux/errno.h>
 18 #include <linux/signal.h>
 19 #include <linux/binfmts.h>
 20 #include <linux/string.h>
 21 #include <linux/file.h>
 22 #include <linux/slab.h>
 23 #include <linux/personality.h>
 24 #include <linux/elfcore.h>
 25 #include <linux/init.h>
 26 #include <linux/highuid.h>
 27 #include <linux/compiler.h>
 28 #include <linux/highmem.h>
 29 #include <linux/pagemap.h>
 30 #include <linux/vmalloc.h>
 31 #include <linux/security.h>
 32 #include <linux/random.h>
 33 #include <linux/elf.h>
 34 #include <linux/elf-randomize.h>
 35 #include <linux/utsname.h>
 36 #include <linux/coredump.h>
 37 #include <linux/sched.h>
 38 #include <linux/dax.h>
 39 #include <asm/uaccess.h>
 40 #include <asm/param.h>
 41 #include <asm/page.h>
 42 
 43 #ifndef user_long_t
 44 #define user_long_t long
 45 #endif
 46 #ifndef user_siginfo_t
 47 #define user_siginfo_t siginfo_t
 48 #endif
 49 
 50 static int load_elf_binary(struct linux_binprm *bprm);
 51 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
 52                                 int, int, unsigned long);
 53 
 54 #ifdef CONFIG_USELIB
 55 static int load_elf_library(struct file *);
 56 #else
 57 #define load_elf_library NULL
 58 #endif
 59 
 60 /*
 61  * If we don't support core dumping, then supply a NULL so we
 62  * don't even try.
 63  */
 64 #ifdef CONFIG_ELF_CORE
 65 static int elf_core_dump(struct coredump_params *cprm);
 66 #else
 67 #define elf_core_dump   NULL
 68 #endif
 69 
 70 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
 71 #define ELF_MIN_ALIGN   ELF_EXEC_PAGESIZE
 72 #else
 73 #define ELF_MIN_ALIGN   PAGE_SIZE
 74 #endif
 75 
 76 #ifndef ELF_CORE_EFLAGS
 77 #define ELF_CORE_EFLAGS 0
 78 #endif
 79 
 80 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
 81 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
 82 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
 83 
 84 static struct linux_binfmt elf_format = {
 85         .module         = THIS_MODULE,
 86         .load_binary    = load_elf_binary,
 87         .load_shlib     = load_elf_library,
 88         .core_dump      = elf_core_dump,
 89         .min_coredump   = ELF_EXEC_PAGESIZE,
 90 };
 91 
 92 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
 93 
 94 static int set_brk(unsigned long start, unsigned long end)
 95 {
 96         start = ELF_PAGEALIGN(start);
 97         end = ELF_PAGEALIGN(end);
 98         if (end > start) {
 99                 int error = vm_brk(start, end - start);
100                 if (error)
101                         return error;
102         }
103         current->mm->start_brk = current->mm->brk = end;
104         return 0;
105 }
106 
107 /* We need to explicitly zero any fractional pages
108    after the data section (i.e. bss).  This would
109    contain the junk from the file that should not
110    be in memory
111  */
112 static int padzero(unsigned long elf_bss)
113 {
114         unsigned long nbyte;
115 
116         nbyte = ELF_PAGEOFFSET(elf_bss);
117         if (nbyte) {
118                 nbyte = ELF_MIN_ALIGN - nbyte;
119                 if (clear_user((void __user *) elf_bss, nbyte))
120                         return -EFAULT;
121         }
122         return 0;
123 }
124 
125 /* Let's use some macros to make this stack manipulation a little clearer */
126 #ifdef CONFIG_STACK_GROWSUP
127 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
128 #define STACK_ROUND(sp, items) \
129         ((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
130 #define STACK_ALLOC(sp, len) ({ \
131         elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
132         old_sp; })
133 #else
134 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
135 #define STACK_ROUND(sp, items) \
136         (((unsigned long) (sp - items)) &~ 15UL)
137 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
138 #endif
139 
140 #ifndef ELF_BASE_PLATFORM
141 /*
142  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
143  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
144  * will be copied to the user stack in the same manner as AT_PLATFORM.
145  */
146 #define ELF_BASE_PLATFORM NULL
147 #endif
148 
149 static int
150 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
151                 unsigned long load_addr, unsigned long interp_load_addr)
152 {
153         unsigned long p = bprm->p;
154         int argc = bprm->argc;
155         int envc = bprm->envc;
156         elf_addr_t __user *argv;
157         elf_addr_t __user *envp;
158         elf_addr_t __user *sp;
159         elf_addr_t __user *u_platform;
160         elf_addr_t __user *u_base_platform;
161         elf_addr_t __user *u_rand_bytes;
162         const char *k_platform = ELF_PLATFORM;
163         const char *k_base_platform = ELF_BASE_PLATFORM;
164         unsigned char k_rand_bytes[16];
165         int items;
166         elf_addr_t *elf_info;
167         int ei_index = 0;
168         const struct cred *cred = current_cred();
169         struct vm_area_struct *vma;
170 
171         /*
172          * In some cases (e.g. Hyper-Threading), we want to avoid L1
173          * evictions by the processes running on the same package. One
174          * thing we can do is to shuffle the initial stack for them.
175          */
176 
177         p = arch_align_stack(p);
178 
179         /*
180          * If this architecture has a platform capability string, copy it
181          * to userspace.  In some cases (Sparc), this info is impossible
182          * for userspace to get any other way, in others (i386) it is
183          * merely difficult.
184          */
185         u_platform = NULL;
186         if (k_platform) {
187                 size_t len = strlen(k_platform) + 1;
188 
189                 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
190                 if (__copy_to_user(u_platform, k_platform, len))
191                         return -EFAULT;
192         }
193 
194         /*
195          * If this architecture has a "base" platform capability
196          * string, copy it to userspace.
197          */
198         u_base_platform = NULL;
199         if (k_base_platform) {
200                 size_t len = strlen(k_base_platform) + 1;
201 
202                 u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
203                 if (__copy_to_user(u_base_platform, k_base_platform, len))
204                         return -EFAULT;
205         }
206 
207         /*
208          * Generate 16 random bytes for userspace PRNG seeding.
209          */
210         get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
211         u_rand_bytes = (elf_addr_t __user *)
212                        STACK_ALLOC(p, sizeof(k_rand_bytes));
213         if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
214                 return -EFAULT;
215 
216         /* Create the ELF interpreter info */
217         elf_info = (elf_addr_t *)current->mm->saved_auxv;
218         /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
219 #define NEW_AUX_ENT(id, val) \
220         do { \
221                 elf_info[ei_index++] = id; \
222                 elf_info[ei_index++] = val; \
223         } while (0)
224 
225 #ifdef ARCH_DLINFO
226         /* 
227          * ARCH_DLINFO must come first so PPC can do its special alignment of
228          * AUXV.
229          * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
230          * ARCH_DLINFO changes
231          */
232         ARCH_DLINFO;
233 #endif
234         NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
235         NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
236         NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
237         NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
238         NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
239         NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
240         NEW_AUX_ENT(AT_BASE, interp_load_addr);
241         NEW_AUX_ENT(AT_FLAGS, 0);
242         NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
243         NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
244         NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
245         NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
246         NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
247         NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
248         NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
249 #ifdef ELF_HWCAP2
250         NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
251 #endif
252         NEW_AUX_ENT(AT_EXECFN, bprm->exec);
253         if (k_platform) {
254                 NEW_AUX_ENT(AT_PLATFORM,
255                             (elf_addr_t)(unsigned long)u_platform);
256         }
257         if (k_base_platform) {
258                 NEW_AUX_ENT(AT_BASE_PLATFORM,
259                             (elf_addr_t)(unsigned long)u_base_platform);
260         }
261         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
262                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
263         }
264 #undef NEW_AUX_ENT
265         /* AT_NULL is zero; clear the rest too */
266         memset(&elf_info[ei_index], 0,
267                sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
268 
269         /* And advance past the AT_NULL entry.  */
270         ei_index += 2;
271 
272         sp = STACK_ADD(p, ei_index);
273 
274         items = (argc + 1) + (envc + 1) + 1;
275         bprm->p = STACK_ROUND(sp, items);
276 
277         /* Point sp at the lowest address on the stack */
278 #ifdef CONFIG_STACK_GROWSUP
279         sp = (elf_addr_t __user *)bprm->p - items - ei_index;
280         bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
281 #else
282         sp = (elf_addr_t __user *)bprm->p;
283 #endif
284 
285 
286         /*
287          * Grow the stack manually; some architectures have a limit on how
288          * far ahead a user-space access may be in order to grow the stack.
289          */
290         vma = find_extend_vma(current->mm, bprm->p);
291         if (!vma)
292                 return -EFAULT;
293 
294         /* Now, let's put argc (and argv, envp if appropriate) on the stack */
295         if (__put_user(argc, sp++))
296                 return -EFAULT;
297         argv = sp;
298         envp = argv + argc + 1;
299 
300         /* Populate argv and envp */
301         p = current->mm->arg_end = current->mm->arg_start;
302         while (argc-- > 0) {
303                 size_t len;
304                 if (__put_user((elf_addr_t)p, argv++))
305                         return -EFAULT;
306                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
307                 if (!len || len > MAX_ARG_STRLEN)
308                         return -EINVAL;
309                 p += len;
310         }
311         if (__put_user(0, argv))
312                 return -EFAULT;
313         current->mm->arg_end = current->mm->env_start = p;
314         while (envc-- > 0) {
315                 size_t len;
316                 if (__put_user((elf_addr_t)p, envp++))
317                         return -EFAULT;
318                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
319                 if (!len || len > MAX_ARG_STRLEN)
320                         return -EINVAL;
321                 p += len;
322         }
323         if (__put_user(0, envp))
324                 return -EFAULT;
325         current->mm->env_end = p;
326 
327         /* Put the elf_info on the stack in the right place.  */
328         sp = (elf_addr_t __user *)envp + 1;
329         if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
330                 return -EFAULT;
331         return 0;
332 }
333 
334 #ifndef elf_map
335 
336 static unsigned long elf_map(struct file *filep, unsigned long addr,
337                 struct elf_phdr *eppnt, int prot, int type,
338                 unsigned long total_size)
339 {
340         unsigned long map_addr;
341         unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
342         unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
343         addr = ELF_PAGESTART(addr);
344         size = ELF_PAGEALIGN(size);
345 
346         /* mmap() will return -EINVAL if given a zero size, but a
347          * segment with zero filesize is perfectly valid */
348         if (!size)
349                 return addr;
350 
351         /*
352         * total_size is the size of the ELF (interpreter) image.
353         * The _first_ mmap needs to know the full size, otherwise
354         * randomization might put this image into an overlapping
355         * position with the ELF binary image. (since size < total_size)
356         * So we first map the 'big' image - and unmap the remainder at
357         * the end. (which unmap is needed for ELF images with holes.)
358         */
359         if (total_size) {
360                 total_size = ELF_PAGEALIGN(total_size);
361                 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
362                 if (!BAD_ADDR(map_addr))
363                         vm_munmap(map_addr+size, total_size-size);
364         } else
365                 map_addr = vm_mmap(filep, addr, size, prot, type, off);
366 
367         return(map_addr);
368 }
369 
370 #endif /* !elf_map */
371 
372 static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
373 {
374         int i, first_idx = -1, last_idx = -1;
375 
376         for (i = 0; i < nr; i++) {
377                 if (cmds[i].p_type == PT_LOAD) {
378                         last_idx = i;
379                         if (first_idx == -1)
380                                 first_idx = i;
381                 }
382         }
383         if (first_idx == -1)
384                 return 0;
385 
386         return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
387                                 ELF_PAGESTART(cmds[first_idx].p_vaddr);
388 }
389 
390 /**
391  * load_elf_phdrs() - load ELF program headers
392  * @elf_ex:   ELF header of the binary whose program headers should be loaded
393  * @elf_file: the opened ELF binary file
394  *
395  * Loads ELF program headers from the binary file elf_file, which has the ELF
396  * header pointed to by elf_ex, into a newly allocated array. The caller is
397  * responsible for freeing the allocated data. Returns an ERR_PTR upon failure.
398  */
399 static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
400                                        struct file *elf_file)
401 {
402         struct elf_phdr *elf_phdata = NULL;
403         int retval, size, err = -1;
404 
405         /*
406          * If the size of this structure has changed, then punt, since
407          * we will be doing the wrong thing.
408          */
409         if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
410                 goto out;
411 
412         /* Sanity check the number of program headers... */
413         if (elf_ex->e_phnum < 1 ||
414                 elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
415                 goto out;
416 
417         /* ...and their total size. */
418         size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
419         if (size > ELF_MIN_ALIGN)
420                 goto out;
421 
422         elf_phdata = kmalloc(size, GFP_KERNEL);
423         if (!elf_phdata)
424                 goto out;
425 
426         /* Read in the program headers */
427         retval = kernel_read(elf_file, elf_ex->e_phoff,
428                              (char *)elf_phdata, size);
429         if (retval != size) {
430                 err = (retval < 0) ? retval : -EIO;
431                 goto out;
432         }
433 
434         /* Success! */
435         err = 0;
436 out:
437         if (err) {
438                 kfree(elf_phdata);
439                 elf_phdata = NULL;
440         }
441         return elf_phdata;
442 }
443 
444 #ifndef CONFIG_ARCH_BINFMT_ELF_STATE
445 
446 /**
447  * struct arch_elf_state - arch-specific ELF loading state
448  *
449  * This structure is used to preserve architecture specific data during
450  * the loading of an ELF file, throughout the checking of architecture
451  * specific ELF headers & through to the point where the ELF load is
452  * known to be proceeding (ie. SET_PERSONALITY).
453  *
454  * This implementation is a dummy for architectures which require no
455  * specific state.
456  */
457 struct arch_elf_state {
458 };
459 
460 #define INIT_ARCH_ELF_STATE {}
461 
462 /**
463  * arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
464  * @ehdr:       The main ELF header
465  * @phdr:       The program header to check
466  * @elf:        The open ELF file
467  * @is_interp:  True if the phdr is from the interpreter of the ELF being
468  *              loaded, else false.
469  * @state:      Architecture-specific state preserved throughout the process
470  *              of loading the ELF.
471  *
472  * Inspects the program header phdr to validate its correctness and/or
473  * suitability for the system. Called once per ELF program header in the
474  * range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
475  * interpreter.
476  *
477  * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
478  *         with that return code.
479  */
480 static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
481                                    struct elf_phdr *phdr,
482                                    struct file *elf, bool is_interp,
483                                    struct arch_elf_state *state)
484 {
485         /* Dummy implementation, always proceed */
486         return 0;
487 }
488 
489 /**
490  * arch_check_elf() - check an ELF executable
491  * @ehdr:       The main ELF header
492  * @has_interp: True if the ELF has an interpreter, else false.
493  * @interp_ehdr: The interpreter's ELF header
494  * @state:      Architecture-specific state preserved throughout the process
495  *              of loading the ELF.
496  *
497  * Provides a final opportunity for architecture code to reject the loading
498  * of the ELF & cause an exec syscall to return an error. This is called after
499  * all program headers to be checked by arch_elf_pt_proc have been.
500  *
501  * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
502  *         with that return code.
503  */
504 static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
505                                  struct elfhdr *interp_ehdr,
506                                  struct arch_elf_state *state)
507 {
508         /* Dummy implementation, always proceed */
509         return 0;
510 }
511 
512 #endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
513 
514 /* This is much more generalized than the library routine read function,
515    so we keep this separate.  Technically the library read function
516    is only provided so that we can read a.out libraries that have
517    an ELF header */
518 
519 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
520                 struct file *interpreter, unsigned long *interp_map_addr,
521                 unsigned long no_base, struct elf_phdr *interp_elf_phdata)
522 {
523         struct elf_phdr *eppnt;
524         unsigned long load_addr = 0;
525         int load_addr_set = 0;
526         unsigned long last_bss = 0, elf_bss = 0;
527         unsigned long error = ~0UL;
528         unsigned long total_size;
529         int i;
530 
531         /* First of all, some simple consistency checks */
532         if (interp_elf_ex->e_type != ET_EXEC &&
533             interp_elf_ex->e_type != ET_DYN)
534                 goto out;
535         if (!elf_check_arch(interp_elf_ex))
536                 goto out;
537         if (!interpreter->f_op->mmap)
538                 goto out;
539 
540         total_size = total_mapping_size(interp_elf_phdata,
541                                         interp_elf_ex->e_phnum);
542         if (!total_size) {
543                 error = -EINVAL;
544                 goto out;
545         }
546 
547         eppnt = interp_elf_phdata;
548         for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
549                 if (eppnt->p_type == PT_LOAD) {
550                         int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
551                         int elf_prot = 0;
552                         unsigned long vaddr = 0;
553                         unsigned long k, map_addr;
554 
555                         if (eppnt->p_flags & PF_R)
556                                 elf_prot = PROT_READ;
557                         if (eppnt->p_flags & PF_W)
558                                 elf_prot |= PROT_WRITE;
559                         if (eppnt->p_flags & PF_X)
560                                 elf_prot |= PROT_EXEC;
561                         vaddr = eppnt->p_vaddr;
562                         if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
563                                 elf_type |= MAP_FIXED;
564                         else if (no_base && interp_elf_ex->e_type == ET_DYN)
565                                 load_addr = -vaddr;
566 
567                         map_addr = elf_map(interpreter, load_addr + vaddr,
568                                         eppnt, elf_prot, elf_type, total_size);
569                         total_size = 0;
570                         if (!*interp_map_addr)
571                                 *interp_map_addr = map_addr;
572                         error = map_addr;
573                         if (BAD_ADDR(map_addr))
574                                 goto out;
575 
576                         if (!load_addr_set &&
577                             interp_elf_ex->e_type == ET_DYN) {
578                                 load_addr = map_addr - ELF_PAGESTART(vaddr);
579                                 load_addr_set = 1;
580                         }
581 
582                         /*
583                          * Check to see if the section's size will overflow the
584                          * allowed task size. Note that p_filesz must always be
585                          * <= p_memsize so it's only necessary to check p_memsz.
586                          */
587                         k = load_addr + eppnt->p_vaddr;
588                         if (BAD_ADDR(k) ||
589                             eppnt->p_filesz > eppnt->p_memsz ||
590                             eppnt->p_memsz > TASK_SIZE ||
591                             TASK_SIZE - eppnt->p_memsz < k) {
592                                 error = -ENOMEM;
593                                 goto out;
594                         }
595 
596                         /*
597                          * Find the end of the file mapping for this phdr, and
598                          * keep track of the largest address we see for this.
599                          */
600                         k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
601                         if (k > elf_bss)
602                                 elf_bss = k;
603 
604                         /*
605                          * Do the same thing for the memory mapping - between
606                          * elf_bss and last_bss is the bss section.
607                          */
608                         k = load_addr + eppnt->p_vaddr + eppnt->p_memsz;
609                         if (k > last_bss)
610                                 last_bss = k;
611                 }
612         }
613 
614         /*
615          * Now fill out the bss section: first pad the last page from
616          * the file up to the page boundary, and zero it from elf_bss
617          * up to the end of the page.
618          */
619         if (padzero(elf_bss)) {
620                 error = -EFAULT;
621                 goto out;
622         }
623         /*
624          * Next, align both the file and mem bss up to the page size,
625          * since this is where elf_bss was just zeroed up to, and where
626          * last_bss will end after the vm_brk() below.
627          */
628         elf_bss = ELF_PAGEALIGN(elf_bss);
629         last_bss = ELF_PAGEALIGN(last_bss);
630         /* Finally, if there is still more bss to allocate, do it. */
631         if (last_bss > elf_bss) {
632                 error = vm_brk(elf_bss, last_bss - elf_bss);
633                 if (error)
634                         goto out;
635         }
636 
637         error = load_addr;
638 out:
639         return error;
640 }
641 
642 /*
643  * These are the functions used to load ELF style executables and shared
644  * libraries.  There is no binary dependent code anywhere else.
645  */
646 
647 #ifndef STACK_RND_MASK
648 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))     /* 8MB of VA */
649 #endif
650 
651 static unsigned long randomize_stack_top(unsigned long stack_top)
652 {
653         unsigned long random_variable = 0;
654 
655         if ((current->flags & PF_RANDOMIZE) &&
656                 !(current->personality & ADDR_NO_RANDOMIZE)) {
657                 random_variable = get_random_long();
658                 random_variable &= STACK_RND_MASK;
659                 random_variable <<= PAGE_SHIFT;
660         }
661 #ifdef CONFIG_STACK_GROWSUP
662         return PAGE_ALIGN(stack_top) + random_variable;
663 #else
664         return PAGE_ALIGN(stack_top) - random_variable;
665 #endif
666 }
667 
668 static int load_elf_binary(struct linux_binprm *bprm)
669 {
670         struct file *interpreter = NULL; /* to shut gcc up */
671         unsigned long load_addr = 0, load_bias = 0;
672         int load_addr_set = 0;
673         char * elf_interpreter = NULL;
674         unsigned long error;
675         struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
676         unsigned long elf_bss, elf_brk;
677         int retval, i;
678         unsigned long elf_entry;
679         unsigned long interp_load_addr = 0;
680         unsigned long start_code, end_code, start_data, end_data;
681         unsigned long reloc_func_desc __maybe_unused = 0;
682         int executable_stack = EXSTACK_DEFAULT;
683         struct pt_regs *regs = current_pt_regs();
684         struct {
685                 struct elfhdr elf_ex;
686                 struct elfhdr interp_elf_ex;
687         } *loc;
688         struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
689 
690         loc = kmalloc(sizeof(*loc), GFP_KERNEL);
691         if (!loc) {
692                 retval = -ENOMEM;
693                 goto out_ret;
694         }
695         
696         /* Get the exec-header */
697         loc->elf_ex = *((struct elfhdr *)bprm->buf);
698 
699         retval = -ENOEXEC;
700         /* First of all, some simple consistency checks */
701         if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
702                 goto out;
703 
704         if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
705                 goto out;
706         if (!elf_check_arch(&loc->elf_ex))
707                 goto out;
708         if (!bprm->file->f_op->mmap)
709                 goto out;
710 
711         elf_phdata = load_elf_phdrs(&loc->elf_ex, bprm->file);
712         if (!elf_phdata)
713                 goto out;
714 
715         elf_ppnt = elf_phdata;
716         elf_bss = 0;
717         elf_brk = 0;
718 
719         start_code = ~0UL;
720         end_code = 0;
721         start_data = 0;
722         end_data = 0;
723 
724         for (i = 0; i < loc->elf_ex.e_phnum; i++) {
725                 if (elf_ppnt->p_type == PT_INTERP) {
726                         /* This is the program interpreter used for
727                          * shared libraries - for now assume that this
728                          * is an a.out format binary
729                          */
730                         retval = -ENOEXEC;
731                         if (elf_ppnt->p_filesz > PATH_MAX || 
732                             elf_ppnt->p_filesz < 2)
733                                 goto out_free_ph;
734 
735                         retval = -ENOMEM;
736                         elf_interpreter = kmalloc(elf_ppnt->p_filesz,
737                                                   GFP_KERNEL);
738                         if (!elf_interpreter)
739                                 goto out_free_ph;
740 
741                         retval = kernel_read(bprm->file, elf_ppnt->p_offset,
742                                              elf_interpreter,
743                                              elf_ppnt->p_filesz);
744                         if (retval != elf_ppnt->p_filesz) {
745                                 if (retval >= 0)
746                                         retval = -EIO;
747                                 goto out_free_interp;
748                         }
749                         /* make sure path is NULL terminated */
750                         retval = -ENOEXEC;
751                         if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
752                                 goto out_free_interp;
753 
754                         interpreter = open_exec(elf_interpreter);
755                         retval = PTR_ERR(interpreter);
756                         if (IS_ERR(interpreter))
757                                 goto out_free_interp;
758 
759                         /*
760                          * If the binary is not readable then enforce
761                          * mm->dumpable = 0 regardless of the interpreter's
762                          * permissions.
763                          */
764                         would_dump(bprm, interpreter);
765 
766                         /* Get the exec headers */
767                         retval = kernel_read(interpreter, 0,
768                                              (void *)&loc->interp_elf_ex,
769                                              sizeof(loc->interp_elf_ex));
770                         if (retval != sizeof(loc->interp_elf_ex)) {
771                                 if (retval >= 0)
772                                         retval = -EIO;
773                                 goto out_free_dentry;
774                         }
775 
776                         break;
777                 }
778                 elf_ppnt++;
779         }
780 
781         elf_ppnt = elf_phdata;
782         for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
783                 switch (elf_ppnt->p_type) {
784                 case PT_GNU_STACK:
785                         if (elf_ppnt->p_flags & PF_X)
786                                 executable_stack = EXSTACK_ENABLE_X;
787                         else
788                                 executable_stack = EXSTACK_DISABLE_X;
789                         break;
790 
791                 case PT_LOPROC ... PT_HIPROC:
792                         retval = arch_elf_pt_proc(&loc->elf_ex, elf_ppnt,
793                                                   bprm->file, false,
794                                                   &arch_state);
795                         if (retval)
796                                 goto out_free_dentry;
797                         break;
798                 }
799 
800         /* Some simple consistency checks for the interpreter */
801         if (elf_interpreter) {
802                 retval = -ELIBBAD;
803                 /* Not an ELF interpreter */
804                 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
805                         goto out_free_dentry;
806                 /* Verify the interpreter has a valid arch */
807                 if (!elf_check_arch(&loc->interp_elf_ex))
808                         goto out_free_dentry;
809 
810                 /* Load the interpreter program headers */
811                 interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
812                                                    interpreter);
813                 if (!interp_elf_phdata)
814                         goto out_free_dentry;
815 
816                 /* Pass PT_LOPROC..PT_HIPROC headers to arch code */
817                 elf_ppnt = interp_elf_phdata;
818                 for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++)
819                         switch (elf_ppnt->p_type) {
820                         case PT_LOPROC ... PT_HIPROC:
821                                 retval = arch_elf_pt_proc(&loc->interp_elf_ex,
822                                                           elf_ppnt, interpreter,
823                                                           true, &arch_state);
824                                 if (retval)
825                                         goto out_free_dentry;
826                                 break;
827                         }
828         }
829 
830         /*
831          * Allow arch code to reject the ELF at this point, whilst it's
832          * still possible to return an error to the code that invoked
833          * the exec syscall.
834          */
835         retval = arch_check_elf(&loc->elf_ex,
836                                 !!interpreter, &loc->interp_elf_ex,
837                                 &arch_state);
838         if (retval)
839                 goto out_free_dentry;
840 
841         /* Flush all traces of the currently running executable */
842         retval = flush_old_exec(bprm);
843         if (retval)
844                 goto out_free_dentry;
845 
846         /* Do this immediately, since STACK_TOP as used in setup_arg_pages
847            may depend on the personality.  */
848         SET_PERSONALITY2(loc->elf_ex, &arch_state);
849         if (elf_read_implies_exec(loc->elf_ex, executable_stack))
850                 current->personality |= READ_IMPLIES_EXEC;
851 
852         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
853                 current->flags |= PF_RANDOMIZE;
854 
855         setup_new_exec(bprm);
856         install_exec_creds(bprm);
857 
858         /* Do this so that we can load the interpreter, if need be.  We will
859            change some of these later */
860         retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
861                                  executable_stack);
862         if (retval < 0)
863                 goto out_free_dentry;
864         
865         current->mm->start_stack = bprm->p;
866 
867         /* Now we do a little grungy work by mmapping the ELF image into
868            the correct location in memory. */
869         for(i = 0, elf_ppnt = elf_phdata;
870             i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
871                 int elf_prot = 0, elf_flags;
872                 unsigned long k, vaddr;
873                 unsigned long total_size = 0;
874 
875                 if (elf_ppnt->p_type != PT_LOAD)
876                         continue;
877 
878                 if (unlikely (elf_brk > elf_bss)) {
879                         unsigned long nbyte;
880                     
881                         /* There was a PT_LOAD segment with p_memsz > p_filesz
882                            before this one. Map anonymous pages, if needed,
883                            and clear the area.  */
884                         retval = set_brk(elf_bss + load_bias,
885                                          elf_brk + load_bias);
886                         if (retval)
887                                 goto out_free_dentry;
888                         nbyte = ELF_PAGEOFFSET(elf_bss);
889                         if (nbyte) {
890                                 nbyte = ELF_MIN_ALIGN - nbyte;
891                                 if (nbyte > elf_brk - elf_bss)
892                                         nbyte = elf_brk - elf_bss;
893                                 if (clear_user((void __user *)elf_bss +
894                                                         load_bias, nbyte)) {
895                                         /*
896                                          * This bss-zeroing can fail if the ELF
897                                          * file specifies odd protections. So
898                                          * we don't check the return value
899                                          */
900                                 }
901                         }
902                 }
903 
904                 if (elf_ppnt->p_flags & PF_R)
905                         elf_prot |= PROT_READ;
906                 if (elf_ppnt->p_flags & PF_W)
907                         elf_prot |= PROT_WRITE;
908                 if (elf_ppnt->p_flags & PF_X)
909                         elf_prot |= PROT_EXEC;
910 
911                 elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
912 
913                 vaddr = elf_ppnt->p_vaddr;
914                 if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
915                         elf_flags |= MAP_FIXED;
916                 } else if (loc->elf_ex.e_type == ET_DYN) {
917                         /* Try and get dynamic programs out of the way of the
918                          * default mmap base, as well as whatever program they
919                          * might try to exec.  This is because the brk will
920                          * follow the loader, and is not movable.  */
921                         load_bias = ELF_ET_DYN_BASE - vaddr;
922                         if (current->flags & PF_RANDOMIZE)
923                                 load_bias += arch_mmap_rnd();
924                         load_bias = ELF_PAGESTART(load_bias);
925                         total_size = total_mapping_size(elf_phdata,
926                                                         loc->elf_ex.e_phnum);
927                         if (!total_size) {
928                                 retval = -EINVAL;
929                                 goto out_free_dentry;
930                         }
931                 }
932 
933                 error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
934                                 elf_prot, elf_flags, total_size);
935                 if (BAD_ADDR(error)) {
936                         retval = IS_ERR((void *)error) ?
937                                 PTR_ERR((void*)error) : -EINVAL;
938                         goto out_free_dentry;
939                 }
940 
941                 if (!load_addr_set) {
942                         load_addr_set = 1;
943                         load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
944                         if (loc->elf_ex.e_type == ET_DYN) {
945                                 load_bias += error -
946                                              ELF_PAGESTART(load_bias + vaddr);
947                                 load_addr += load_bias;
948                                 reloc_func_desc = load_bias;
949                         }
950                 }
951                 k = elf_ppnt->p_vaddr;
952                 if (k < start_code)
953                         start_code = k;
954                 if (start_data < k)
955                         start_data = k;
956 
957                 /*
958                  * Check to see if the section's size will overflow the
959                  * allowed task size. Note that p_filesz must always be
960                  * <= p_memsz so it is only necessary to check p_memsz.
961                  */
962                 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
963                     elf_ppnt->p_memsz > TASK_SIZE ||
964                     TASK_SIZE - elf_ppnt->p_memsz < k) {
965                         /* set_brk can never work. Avoid overflows. */
966                         retval = -EINVAL;
967                         goto out_free_dentry;
968                 }
969 
970                 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
971 
972                 if (k > elf_bss)
973                         elf_bss = k;
974                 if ((elf_ppnt->p_flags & PF_X) && end_code < k)
975                         end_code = k;
976                 if (end_data < k)
977                         end_data = k;
978                 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
979                 if (k > elf_brk)
980                         elf_brk = k;
981         }
982 
983         loc->elf_ex.e_entry += load_bias;
984         elf_bss += load_bias;
985         elf_brk += load_bias;
986         start_code += load_bias;
987         end_code += load_bias;
988         start_data += load_bias;
989         end_data += load_bias;
990 
991         /* Calling set_brk effectively mmaps the pages that we need
992          * for the bss and break sections.  We must do this before
993          * mapping in the interpreter, to make sure it doesn't wind
994          * up getting placed where the bss needs to go.
995          */
996         retval = set_brk(elf_bss, elf_brk);
997         if (retval)
998                 goto out_free_dentry;
999         if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
1000                 retval = -EFAULT; /* Nobody gets to see this, but.. */
1001                 goto out_free_dentry;
1002         }
1003 
1004         if (elf_interpreter) {
1005                 unsigned long interp_map_addr = 0;
1006 
1007                 elf_entry = load_elf_interp(&loc->interp_elf_ex,
1008                                             interpreter,
1009                                             &interp_map_addr,
1010                                             load_bias, interp_elf_phdata);
1011                 if (!IS_ERR((void *)elf_entry)) {
1012                         /*
1013                          * load_elf_interp() returns relocation
1014                          * adjustment
1015                          */
1016                         interp_load_addr = elf_entry;
1017                         elf_entry += loc->interp_elf_ex.e_entry;
1018                 }
1019                 if (BAD_ADDR(elf_entry)) {
1020                         retval = IS_ERR((void *)elf_entry) ?
1021                                         (int)elf_entry : -EINVAL;
1022                         goto out_free_dentry;
1023                 }
1024                 reloc_func_desc = interp_load_addr;
1025 
1026                 allow_write_access(interpreter);
1027                 fput(interpreter);
1028                 kfree(elf_interpreter);
1029         } else {
1030                 elf_entry = loc->elf_ex.e_entry;
1031                 if (BAD_ADDR(elf_entry)) {
1032                         retval = -EINVAL;
1033                         goto out_free_dentry;
1034                 }
1035         }
1036 
1037         kfree(interp_elf_phdata);
1038         kfree(elf_phdata);
1039 
1040         set_binfmt(&elf_format);
1041 
1042 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
1043         retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
1044         if (retval < 0)
1045                 goto out;
1046 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
1047 
1048         retval = create_elf_tables(bprm, &loc->elf_ex,
1049                           load_addr, interp_load_addr);
1050         if (retval < 0)
1051                 goto out;
1052         /* N.B. passed_fileno might not be initialized? */
1053         current->mm->end_code = end_code;
1054         current->mm->start_code = start_code;
1055         current->mm->start_data = start_data;
1056         current->mm->end_data = end_data;
1057         current->mm->start_stack = bprm->p;
1058 
1059         if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
1060                 current->mm->brk = current->mm->start_brk =
1061                         arch_randomize_brk(current->mm);
1062 #ifdef compat_brk_randomized
1063                 current->brk_randomized = 1;
1064 #endif
1065         }
1066 
1067         if (current->personality & MMAP_PAGE_ZERO) {
1068                 /* Why this, you ask???  Well SVr4 maps page 0 as read-only,
1069                    and some applications "depend" upon this behavior.
1070                    Since we do not have the power to recompile these, we
1071                    emulate the SVr4 behavior. Sigh. */
1072                 error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
1073                                 MAP_FIXED | MAP_PRIVATE, 0);
1074         }
1075 
1076 #ifdef ELF_PLAT_INIT
1077         /*
1078          * The ABI may specify that certain registers be set up in special
1079          * ways (on i386 %edx is the address of a DT_FINI function, for
1080          * example.  In addition, it may also specify (eg, PowerPC64 ELF)
1081          * that the e_entry field is the address of the function descriptor
1082          * for the startup routine, rather than the address of the startup
1083          * routine itself.  This macro performs whatever initialization to
1084          * the regs structure is required as well as any relocations to the
1085          * function descriptor entries when executing dynamically links apps.
1086          */
1087         ELF_PLAT_INIT(regs, reloc_func_desc);
1088 #endif
1089 
1090         start_thread(regs, elf_entry, bprm->p);
1091         retval = 0;
1092 out:
1093         kfree(loc);
1094 out_ret:
1095         return retval;
1096 
1097         /* error cleanup */
1098 out_free_dentry:
1099         kfree(interp_elf_phdata);
1100         allow_write_access(interpreter);
1101         if (interpreter)
1102                 fput(interpreter);
1103 out_free_interp:
1104         kfree(elf_interpreter);
1105 out_free_ph:
1106         kfree(elf_phdata);
1107         goto out;
1108 }
1109 
1110 #ifdef CONFIG_USELIB
1111 /* This is really simpleminded and specialized - we are loading an
1112    a.out library that is given an ELF header. */
1113 static int load_elf_library(struct file *file)
1114 {
1115         struct elf_phdr *elf_phdata;
1116         struct elf_phdr *eppnt;
1117         unsigned long elf_bss, bss, len;
1118         int retval, error, i, j;
1119         struct elfhdr elf_ex;
1120 
1121         error = -ENOEXEC;
1122         retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1123         if (retval != sizeof(elf_ex))
1124                 goto out;
1125 
1126         if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1127                 goto out;
1128 
1129         /* First of all, some simple consistency checks */
1130         if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1131             !elf_check_arch(&elf_ex) || !file->f_op->mmap)
1132                 goto out;
1133 
1134         /* Now read in all of the header information */
1135 
1136         j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1137         /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1138 
1139         error = -ENOMEM;
1140         elf_phdata = kmalloc(j, GFP_KERNEL);
1141         if (!elf_phdata)
1142                 goto out;
1143 
1144         eppnt = elf_phdata;
1145         error = -ENOEXEC;
1146         retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1147         if (retval != j)
1148                 goto out_free_ph;
1149 
1150         for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1151                 if ((eppnt + i)->p_type == PT_LOAD)
1152                         j++;
1153         if (j != 1)
1154                 goto out_free_ph;
1155 
1156         while (eppnt->p_type != PT_LOAD)
1157                 eppnt++;
1158 
1159         /* Now use mmap to map the library into memory. */
1160         error = vm_mmap(file,
1161                         ELF_PAGESTART(eppnt->p_vaddr),
1162                         (eppnt->p_filesz +
1163                          ELF_PAGEOFFSET(eppnt->p_vaddr)),
1164                         PROT_READ | PROT_WRITE | PROT_EXEC,
1165                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1166                         (eppnt->p_offset -
1167                          ELF_PAGEOFFSET(eppnt->p_vaddr)));
1168         if (error != ELF_PAGESTART(eppnt->p_vaddr))
1169                 goto out_free_ph;
1170 
1171         elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1172         if (padzero(elf_bss)) {
1173                 error = -EFAULT;
1174                 goto out_free_ph;
1175         }
1176 
1177         len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1178                             ELF_MIN_ALIGN - 1);
1179         bss = eppnt->p_memsz + eppnt->p_vaddr;
1180         if (bss > len) {
1181                 error = vm_brk(len, bss - len);
1182                 if (error)
1183                         goto out_free_ph;
1184         }
1185         error = 0;
1186 
1187 out_free_ph:
1188         kfree(elf_phdata);
1189 out:
1190         return error;
1191 }
1192 #endif /* #ifdef CONFIG_USELIB */
1193 
1194 #ifdef CONFIG_ELF_CORE
1195 /*
1196  * ELF core dumper
1197  *
1198  * Modelled on fs/exec.c:aout_core_dump()
1199  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1200  */
1201 
1202 /*
1203  * The purpose of always_dump_vma() is to make sure that special kernel mappings
1204  * that are useful for post-mortem analysis are included in every core dump.
1205  * In that way we ensure that the core dump is fully interpretable later
1206  * without matching up the same kernel and hardware config to see what PC values
1207  * meant. These special mappings include - vDSO, vsyscall, and other
1208  * architecture specific mappings
1209  */
1210 static bool always_dump_vma(struct vm_area_struct *vma)
1211 {
1212         /* Any vsyscall mappings? */
1213         if (vma == get_gate_vma(vma->vm_mm))
1214                 return true;
1215 
1216         /*
1217          * Assume that all vmas with a .name op should always be dumped.
1218          * If this changes, a new vm_ops field can easily be added.
1219          */
1220         if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
1221                 return true;
1222 
1223         /*
1224          * arch_vma_name() returns non-NULL for special architecture mappings,
1225          * such as vDSO sections.
1226          */
1227         if (arch_vma_name(vma))
1228                 return true;
1229 
1230         return false;
1231 }
1232 
1233 /*
1234  * Decide what to dump of a segment, part, all or none.
1235  */
1236 static unsigned long vma_dump_size(struct vm_area_struct *vma,
1237                                    unsigned long mm_flags)
1238 {
1239 #define FILTER(type)    (mm_flags & (1UL << MMF_DUMP_##type))
1240 
1241         /* always dump the vdso and vsyscall sections */
1242         if (always_dump_vma(vma))
1243                 goto whole;
1244 
1245         if (vma->vm_flags & VM_DONTDUMP)
1246                 return 0;
1247 
1248         /* support for DAX */
1249         if (vma_is_dax(vma)) {
1250                 if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
1251                         goto whole;
1252                 if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
1253                         goto whole;
1254                 return 0;
1255         }
1256 
1257         /* Hugetlb memory check */
1258         if (vma->vm_flags & VM_HUGETLB) {
1259                 if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
1260                         goto whole;
1261                 if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
1262                         goto whole;
1263                 return 0;
1264         }
1265 
1266         /* Do not dump I/O mapped devices or special mappings */
1267         if (vma->vm_flags & VM_IO)
1268                 return 0;
1269 
1270         /* By default, dump shared memory if mapped from an anonymous file. */
1271         if (vma->vm_flags & VM_SHARED) {
1272                 if (file_inode(vma->vm_file)->i_nlink == 0 ?
1273                     FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
1274                         goto whole;
1275                 return 0;
1276         }
1277 
1278         /* Dump segments that have been written to.  */
1279         if (vma->anon_vma && FILTER(ANON_PRIVATE))
1280                 goto whole;
1281         if (vma->vm_file == NULL)
1282                 return 0;
1283 
1284         if (FILTER(MAPPED_PRIVATE))
1285                 goto whole;
1286 
1287         /*
1288          * If this looks like the beginning of a DSO or executable mapping,
1289          * check for an ELF header.  If we find one, dump the first page to
1290          * aid in determining what was mapped here.
1291          */
1292         if (FILTER(ELF_HEADERS) &&
1293             vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
1294                 u32 __user *header = (u32 __user *) vma->vm_start;
1295                 u32 word;
1296                 mm_segment_t fs = get_fs();
1297                 /*
1298                  * Doing it this way gets the constant folded by GCC.
1299                  */
1300                 union {
1301                         u32 cmp;
1302                         char elfmag[SELFMAG];
1303                 } magic;
1304                 BUILD_BUG_ON(SELFMAG != sizeof word);
1305                 magic.elfmag[EI_MAG0] = ELFMAG0;
1306                 magic.elfmag[EI_MAG1] = ELFMAG1;
1307                 magic.elfmag[EI_MAG2] = ELFMAG2;
1308                 magic.elfmag[EI_MAG3] = ELFMAG3;
1309                 /*
1310                  * Switch to the user "segment" for get_user(),
1311                  * then put back what elf_core_dump() had in place.
1312                  */
1313                 set_fs(USER_DS);
1314                 if (unlikely(get_user(word, header)))
1315                         word = 0;
1316                 set_fs(fs);
1317                 if (word == magic.cmp)
1318                         return PAGE_SIZE;
1319         }
1320 
1321 #undef  FILTER
1322 
1323         return 0;
1324 
1325 whole:
1326         return vma->vm_end - vma->vm_start;
1327 }
1328 
1329 /* An ELF note in memory */
1330 struct memelfnote
1331 {
1332         const char *name;
1333         int type;
1334         unsigned int datasz;
1335         void *data;
1336 };
1337 
1338 static int notesize(struct memelfnote *en)
1339 {
1340         int sz;
1341 
1342         sz = sizeof(struct elf_note);
1343         sz += roundup(strlen(en->name) + 1, 4);
1344         sz += roundup(en->datasz, 4);
1345 
1346         return sz;
1347 }
1348 
1349 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1350 {
1351         struct elf_note en;
1352         en.n_namesz = strlen(men->name) + 1;
1353         en.n_descsz = men->datasz;
1354         en.n_type = men->type;
1355 
1356         return dump_emit(cprm, &en, sizeof(en)) &&
1357             dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1358             dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1359 }
1360 
1361 static void fill_elf_header(struct elfhdr *elf, int segs,
1362                             u16 machine, u32 flags)
1363 {
1364         memset(elf, 0, sizeof(*elf));
1365 
1366         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1367         elf->e_ident[EI_CLASS] = ELF_CLASS;
1368         elf->e_ident[EI_DATA] = ELF_DATA;
1369         elf->e_ident[EI_VERSION] = EV_CURRENT;
1370         elf->e_ident[EI_OSABI] = ELF_OSABI;
1371 
1372         elf->e_type = ET_CORE;
1373         elf->e_machine = machine;
1374         elf->e_version = EV_CURRENT;
1375         elf->e_phoff = sizeof(struct elfhdr);
1376         elf->e_flags = flags;
1377         elf->e_ehsize = sizeof(struct elfhdr);
1378         elf->e_phentsize = sizeof(struct elf_phdr);
1379         elf->e_phnum = segs;
1380 
1381         return;
1382 }
1383 
1384 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1385 {
1386         phdr->p_type = PT_NOTE;
1387         phdr->p_offset = offset;
1388         phdr->p_vaddr = 0;
1389         phdr->p_paddr = 0;
1390         phdr->p_filesz = sz;
1391         phdr->p_memsz = 0;
1392         phdr->p_flags = 0;
1393         phdr->p_align = 0;
1394         return;
1395 }
1396 
1397 static void fill_note(struct memelfnote *note, const char *name, int type, 
1398                 unsigned int sz, void *data)
1399 {
1400         note->name = name;
1401         note->type = type;
1402         note->datasz = sz;
1403         note->data = data;
1404         return;
1405 }
1406 
1407 /*
1408  * fill up all the fields in prstatus from the given task struct, except
1409  * registers which need to be filled up separately.
1410  */
1411 static void fill_prstatus(struct elf_prstatus *prstatus,
1412                 struct task_struct *p, long signr)
1413 {
1414         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1415         prstatus->pr_sigpend = p->pending.signal.sig[0];
1416         prstatus->pr_sighold = p->blocked.sig[0];
1417         rcu_read_lock();
1418         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1419         rcu_read_unlock();
1420         prstatus->pr_pid = task_pid_vnr(p);
1421         prstatus->pr_pgrp = task_pgrp_vnr(p);
1422         prstatus->pr_sid = task_session_vnr(p);
1423         if (thread_group_leader(p)) {
1424                 struct task_cputime cputime;
1425 
1426                 /*
1427                  * This is the record for the group leader.  It shows the
1428                  * group-wide total, not its individual thread total.
1429                  */
1430                 thread_group_cputime(p, &cputime);
1431                 cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1432                 cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1433         } else {
1434                 cputime_t utime, stime;
1435 
1436                 task_cputime(p, &utime, &stime);
1437                 cputime_to_timeval(utime, &prstatus->pr_utime);
1438                 cputime_to_timeval(stime, &prstatus->pr_stime);
1439         }
1440         cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1441         cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1442 }
1443 
1444 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1445                        struct mm_struct *mm)
1446 {
1447         const struct cred *cred;
1448         unsigned int i, len;
1449         
1450         /* first copy the parameters from user space */
1451         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1452 
1453         len = mm->arg_end - mm->arg_start;
1454         if (len >= ELF_PRARGSZ)
1455                 len = ELF_PRARGSZ-1;
1456         if (copy_from_user(&psinfo->pr_psargs,
1457                            (const char __user *)mm->arg_start, len))
1458                 return -EFAULT;
1459         for(i = 0; i < len; i++)
1460                 if (psinfo->pr_psargs[i] == 0)
1461                         psinfo->pr_psargs[i] = ' ';
1462         psinfo->pr_psargs[len] = 0;
1463 
1464         rcu_read_lock();
1465         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1466         rcu_read_unlock();
1467         psinfo->pr_pid = task_pid_vnr(p);
1468         psinfo->pr_pgrp = task_pgrp_vnr(p);
1469         psinfo->pr_sid = task_session_vnr(p);
1470 
1471         i = p->state ? ffz(~p->state) + 1 : 0;
1472         psinfo->pr_state = i;
1473         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1474         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1475         psinfo->pr_nice = task_nice(p);
1476         psinfo->pr_flag = p->flags;
1477         rcu_read_lock();
1478         cred = __task_cred(p);
1479         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1480         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1481         rcu_read_unlock();
1482         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1483         
1484         return 0;
1485 }
1486 
1487 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1488 {
1489         elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1490         int i = 0;
1491         do
1492                 i += 2;
1493         while (auxv[i - 2] != AT_NULL);
1494         fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1495 }
1496 
1497 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
1498                 const siginfo_t *siginfo)
1499 {
1500         mm_segment_t old_fs = get_fs();
1501         set_fs(KERNEL_DS);
1502         copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
1503         set_fs(old_fs);
1504         fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
1505 }
1506 
1507 #define MAX_FILE_NOTE_SIZE (4*1024*1024)
1508 /*
1509  * Format of NT_FILE note:
1510  *
1511  * long count     -- how many files are mapped
1512  * long page_size -- units for file_ofs
1513  * array of [COUNT] elements of
1514  *   long start
1515  *   long end
1516  *   long file_ofs
1517  * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
1518  */
1519 static int fill_files_note(struct memelfnote *note)
1520 {
1521         struct vm_area_struct *vma;
1522         unsigned count, size, names_ofs, remaining, n;
1523         user_long_t *data;
1524         user_long_t *start_end_ofs;
1525         char *name_base, *name_curpos;
1526 
1527         /* *Estimated* file count and total data size needed */
1528         count = current->mm->map_count;
1529         size = count * 64;
1530 
1531         names_ofs = (2 + 3 * count) * sizeof(data[0]);
1532  alloc:
1533         if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
1534                 return -EINVAL;
1535         size = round_up(size, PAGE_SIZE);
1536         data = vmalloc(size);
1537         if (!data)
1538                 return -ENOMEM;
1539 
1540         start_end_ofs = data + 2;
1541         name_base = name_curpos = ((char *)data) + names_ofs;
1542         remaining = size - names_ofs;
1543         count = 0;
1544         for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
1545                 struct file *file;
1546                 const char *filename;
1547 
1548                 file = vma->vm_file;
1549                 if (!file)
1550                         continue;
1551                 filename = file_path(file, name_curpos, remaining);
1552                 if (IS_ERR(filename)) {
1553                         if (PTR_ERR(filename) == -ENAMETOOLONG) {
1554                                 vfree(data);
1555                                 size = size * 5 / 4;
1556                                 goto alloc;
1557                         }
1558                         continue;
1559                 }
1560 
1561                 /* file_path() fills at the end, move name down */
1562                 /* n = strlen(filename) + 1: */
1563                 n = (name_curpos + remaining) - filename;
1564                 remaining = filename - name_curpos;
1565                 memmove(name_curpos, filename, n);
1566                 name_curpos += n;
1567 
1568                 *start_end_ofs++ = vma->vm_start;
1569                 *start_end_ofs++ = vma->vm_end;
1570                 *start_end_ofs++ = vma->vm_pgoff;
1571                 count++;
1572         }
1573 
1574         /* Now we know exact count of files, can store it */
1575         data[0] = count;
1576         data[1] = PAGE_SIZE;
1577         /*
1578          * Count usually is less than current->mm->map_count,
1579          * we need to move filenames down.
1580          */
1581         n = current->mm->map_count - count;
1582         if (n != 0) {
1583                 unsigned shift_bytes = n * 3 * sizeof(data[0]);
1584                 memmove(name_base - shift_bytes, name_base,
1585                         name_curpos - name_base);
1586                 name_curpos -= shift_bytes;
1587         }
1588 
1589         size = name_curpos - (char *)data;
1590         fill_note(note, "CORE", NT_FILE, size, data);
1591         return 0;
1592 }
1593 
1594 #ifdef CORE_DUMP_USE_REGSET
1595 #include <linux/regset.h>
1596 
1597 struct elf_thread_core_info {
1598         struct elf_thread_core_info *next;
1599         struct task_struct *task;
1600         struct elf_prstatus prstatus;
1601         struct memelfnote notes[0];
1602 };
1603 
1604 struct elf_note_info {
1605         struct elf_thread_core_info *thread;
1606         struct memelfnote psinfo;
1607         struct memelfnote signote;
1608         struct memelfnote auxv;
1609         struct memelfnote files;
1610         user_siginfo_t csigdata;
1611         size_t size;
1612         int thread_notes;
1613 };
1614 
1615 /*
1616  * When a regset has a writeback hook, we call it on each thread before
1617  * dumping user memory.  On register window machines, this makes sure the
1618  * user memory backing the register data is up to date before we read it.
1619  */
1620 static void do_thread_regset_writeback(struct task_struct *task,
1621                                        const struct user_regset *regset)
1622 {
1623         if (regset->writeback)
1624                 regset->writeback(task, regset, 1);
1625 }
1626 
1627 #ifndef PR_REG_SIZE
1628 #define PR_REG_SIZE(S) sizeof(S)
1629 #endif
1630 
1631 #ifndef PRSTATUS_SIZE
1632 #define PRSTATUS_SIZE(S) sizeof(S)
1633 #endif
1634 
1635 #ifndef PR_REG_PTR
1636 #define PR_REG_PTR(S) (&((S)->pr_reg))
1637 #endif
1638 
1639 #ifndef SET_PR_FPVALID
1640 #define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V))
1641 #endif
1642 
1643 static int fill_thread_core_info(struct elf_thread_core_info *t,
1644                                  const struct user_regset_view *view,
1645                                  long signr, size_t *total)
1646 {
1647         unsigned int i;
1648 
1649         /*
1650          * NT_PRSTATUS is the one special case, because the regset data
1651          * goes into the pr_reg field inside the note contents, rather
1652          * than being the whole note contents.  We fill the reset in here.
1653          * We assume that regset 0 is NT_PRSTATUS.
1654          */
1655         fill_prstatus(&t->prstatus, t->task, signr);
1656         (void) view->regsets[0].get(t->task, &view->regsets[0],
1657                                     0, PR_REG_SIZE(t->prstatus.pr_reg),
1658                                     PR_REG_PTR(&t->prstatus), NULL);
1659 
1660         fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1661                   PRSTATUS_SIZE(t->prstatus), &t->prstatus);
1662         *total += notesize(&t->notes[0]);
1663 
1664         do_thread_regset_writeback(t->task, &view->regsets[0]);
1665 
1666         /*
1667          * Each other regset might generate a note too.  For each regset
1668          * that has no core_note_type or is inactive, we leave t->notes[i]
1669          * all zero and we'll know to skip writing it later.
1670          */
1671         for (i = 1; i < view->n; ++i) {
1672                 const struct user_regset *regset = &view->regsets[i];
1673                 do_thread_regset_writeback(t->task, regset);
1674                 if (regset->core_note_type && regset->get &&
1675                     (!regset->active || regset->active(t->task, regset))) {
1676                         int ret;
1677                         size_t size = regset->n * regset->size;
1678                         void *data = kmalloc(size, GFP_KERNEL);
1679                         if (unlikely(!data))
1680                                 return 0;
1681                         ret = regset->get(t->task, regset,
1682                                           0, size, data, NULL);
1683                         if (unlikely(ret))
1684                                 kfree(data);
1685                         else {
1686                                 if (regset->core_note_type != NT_PRFPREG)
1687                                         fill_note(&t->notes[i], "LINUX",
1688                                                   regset->core_note_type,
1689                                                   size, data);
1690                                 else {
1691                                         SET_PR_FPVALID(&t->prstatus, 1);
1692                                         fill_note(&t->notes[i], "CORE",
1693                                                   NT_PRFPREG, size, data);
1694                                 }
1695                                 *total += notesize(&t->notes[i]);
1696                         }
1697                 }
1698         }
1699 
1700         return 1;
1701 }
1702 
1703 static int fill_note_info(struct elfhdr *elf, int phdrs,
1704                           struct elf_note_info *info,
1705                           const siginfo_t *siginfo, struct pt_regs *regs)
1706 {
1707         struct task_struct *dump_task = current;
1708         const struct user_regset_view *view = task_user_regset_view(dump_task);
1709         struct elf_thread_core_info *t;
1710         struct elf_prpsinfo *psinfo;
1711         struct core_thread *ct;
1712         unsigned int i;
1713 
1714         info->size = 0;
1715         info->thread = NULL;
1716 
1717         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1718         if (psinfo == NULL) {
1719                 info->psinfo.data = NULL; /* So we don't free this wrongly */
1720                 return 0;
1721         }
1722 
1723         fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1724 
1725         /*
1726          * Figure out how many notes we're going to need for each thread.
1727          */
1728         info->thread_notes = 0;
1729         for (i = 0; i < view->n; ++i)
1730                 if (view->regsets[i].core_note_type != 0)
1731                         ++info->thread_notes;
1732 
1733         /*
1734          * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
1735          * since it is our one special case.
1736          */
1737         if (unlikely(info->thread_notes == 0) ||
1738             unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1739                 WARN_ON(1);
1740                 return 0;
1741         }
1742 
1743         /*
1744          * Initialize the ELF file header.
1745          */
1746         fill_elf_header(elf, phdrs,
1747                         view->e_machine, view->e_flags);
1748 
1749         /*
1750          * Allocate a structure for each thread.
1751          */
1752         for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
1753                 t = kzalloc(offsetof(struct elf_thread_core_info,
1754                                      notes[info->thread_notes]),
1755                             GFP_KERNEL);
1756                 if (unlikely(!t))
1757                         return 0;
1758 
1759                 t->task = ct->task;
1760                 if (ct->task == dump_task || !info->thread) {
1761                         t->next = info->thread;
1762                         info->thread = t;
1763                 } else {
1764                         /*
1765                          * Make sure to keep the original task at
1766                          * the head of the list.
1767                          */
1768                         t->next = info->thread->next;
1769                         info->thread->next = t;
1770                 }
1771         }
1772 
1773         /*
1774          * Now fill in each thread's information.
1775          */
1776         for (t = info->thread; t != NULL; t = t->next)
1777                 if (!fill_thread_core_info(t, view, siginfo->si_signo, &info->size))
1778                         return 0;
1779 
1780         /*
1781          * Fill in the two process-wide notes.
1782          */
1783         fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1784         info->size += notesize(&info->psinfo);
1785 
1786         fill_siginfo_note(&info->signote, &info->csigdata, siginfo);
1787         info->size += notesize(&info->signote);
1788 
1789         fill_auxv_note(&info->auxv, current->mm);
1790         info->size += notesize(&info->auxv);
1791 
1792         if (fill_files_note(&info->files) == 0)
1793                 info->size += notesize(&info->files);
1794 
1795         return 1;
1796 }
1797 
1798 static size_t get_note_info_size(struct elf_note_info *info)
1799 {
1800         return info->size;
1801 }
1802 
1803 /*
1804  * Write all the notes for each thread.  When writing the first thread, the
1805  * process-wide notes are interleaved after the first thread-specific note.
1806  */
1807 static int write_note_info(struct elf_note_info *info,
1808                            struct coredump_params *cprm)
1809 {
1810         bool first = true;
1811         struct elf_thread_core_info *t = info->thread;
1812 
1813         do {
1814                 int i;
1815 
1816                 if (!writenote(&t->notes[0], cprm))
1817                         return 0;
1818 
1819                 if (first && !writenote(&info->psinfo, cprm))
1820                         return 0;
1821                 if (first && !writenote(&info->signote, cprm))
1822                         return 0;
1823                 if (first && !writenote(&info->auxv, cprm))
1824                         return 0;
1825                 if (first && info->files.data &&
1826                                 !writenote(&info->files, cprm))
1827                         return 0;
1828 
1829                 for (i = 1; i < info->thread_notes; ++i)
1830                         if (t->notes[i].data &&
1831                             !writenote(&t->notes[i], cprm))
1832                                 return 0;
1833 
1834                 first = false;
1835                 t = t->next;
1836         } while (t);
1837 
1838         return 1;
1839 }
1840 
1841 static void free_note_info(struct elf_note_info *info)
1842 {
1843         struct elf_thread_core_info *threads = info->thread;
1844         while (threads) {
1845                 unsigned int i;
1846                 struct elf_thread_core_info *t = threads;
1847                 threads = t->next;
1848                 WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
1849                 for (i = 1; i < info->thread_notes; ++i)
1850                         kfree(t->notes[i].data);
1851                 kfree(t);
1852         }
1853         kfree(info->psinfo.data);
1854         vfree(info->files.data);
1855 }
1856 
1857 #else
1858 
1859 /* Here is the structure in which status of each thread is captured. */
1860 struct elf_thread_status
1861 {
1862         struct list_head list;
1863         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1864         elf_fpregset_t fpu;             /* NT_PRFPREG */
1865         struct task_struct *thread;
1866 #ifdef ELF_CORE_COPY_XFPREGS
1867         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1868 #endif
1869         struct memelfnote notes[3];
1870         int num_notes;
1871 };
1872 
1873 /*
1874  * In order to add the specific thread information for the elf file format,
1875  * we need to keep a linked list of every threads pr_status and then create
1876  * a single section for them in the final core file.
1877  */
1878 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1879 {
1880         int sz = 0;
1881         struct task_struct *p = t->thread;
1882         t->num_notes = 0;
1883 
1884         fill_prstatus(&t->prstatus, p, signr);
1885         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);        
1886         
1887         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1888                   &(t->prstatus));
1889         t->num_notes++;
1890         sz += notesize(&t->notes[0]);
1891 
1892         if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1893                                                                 &t->fpu))) {
1894                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1895                           &(t->fpu));
1896                 t->num_notes++;
1897                 sz += notesize(&t->notes[1]);
1898         }
1899 
1900 #ifdef ELF_CORE_COPY_XFPREGS
1901         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1902                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1903                           sizeof(t->xfpu), &t->xfpu);
1904                 t->num_notes++;
1905                 sz += notesize(&t->notes[2]);
1906         }
1907 #endif  
1908         return sz;
1909 }
1910 
1911 struct elf_note_info {
1912         struct memelfnote *notes;
1913         struct memelfnote *notes_files;
1914         struct elf_prstatus *prstatus;  /* NT_PRSTATUS */
1915         struct elf_prpsinfo *psinfo;    /* NT_PRPSINFO */
1916         struct list_head thread_list;
1917         elf_fpregset_t *fpu;
1918 #ifdef ELF_CORE_COPY_XFPREGS
1919         elf_fpxregset_t *xfpu;
1920 #endif
1921         user_siginfo_t csigdata;
1922         int thread_status_size;
1923         int numnote;
1924 };
1925 
1926 static int elf_note_info_init(struct elf_note_info *info)
1927 {
1928         memset(info, 0, sizeof(*info));
1929         INIT_LIST_HEAD(&info->thread_list);
1930 
1931         /* Allocate space for ELF notes */
1932         info->notes = kmalloc(8 * sizeof(struct memelfnote), GFP_KERNEL);
1933         if (!info->notes)
1934                 return 0;
1935         info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
1936         if (!info->psinfo)
1937                 return 0;
1938         info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
1939         if (!info->prstatus)
1940                 return 0;
1941         info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
1942         if (!info->fpu)
1943                 return 0;
1944 #ifdef ELF_CORE_COPY_XFPREGS
1945         info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
1946         if (!info->xfpu)
1947                 return 0;
1948 #endif
1949         return 1;
1950 }
1951 
1952 static int fill_note_info(struct elfhdr *elf, int phdrs,
1953                           struct elf_note_info *info,
1954                           const siginfo_t *siginfo, struct pt_regs *regs)
1955 {
1956         struct list_head *t;
1957         struct core_thread *ct;
1958         struct elf_thread_status *ets;
1959 
1960         if (!elf_note_info_init(info))
1961                 return 0;
1962 
1963         for (ct = current->mm->core_state->dumper.next;
1964                                         ct; ct = ct->next) {
1965                 ets = kzalloc(sizeof(*ets), GFP_KERNEL);
1966                 if (!ets)
1967                         return 0;
1968 
1969                 ets->thread = ct->task;
1970                 list_add(&ets->list, &info->thread_list);
1971         }
1972 
1973         list_for_each(t, &info->thread_list) {
1974                 int sz;
1975 
1976                 ets = list_entry(t, struct elf_thread_status, list);
1977                 sz = elf_dump_thread_status(siginfo->si_signo, ets);
1978                 info->thread_status_size += sz;
1979         }
1980         /* now collect the dump for the current */
1981         memset(info->prstatus, 0, sizeof(*info->prstatus));
1982         fill_prstatus(info->prstatus, current, siginfo->si_signo);
1983         elf_core_copy_regs(&info->prstatus->pr_reg, regs);
1984 
1985         /* Set up header */
1986         fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
1987 
1988         /*
1989          * Set up the notes in similar form to SVR4 core dumps made
1990          * with info from their /proc.
1991          */
1992 
1993         fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
1994                   sizeof(*info->prstatus), info->prstatus);
1995         fill_psinfo(info->psinfo, current->group_leader, current->mm);
1996         fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
1997                   sizeof(*info->psinfo), info->psinfo);
1998 
1999         fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo);
2000         fill_auxv_note(info->notes + 3, current->mm);
2001         info->numnote = 4;
2002 
2003         if (fill_files_note(info->notes + info->numnote) == 0) {
2004                 info->notes_files = info->notes + info->numnote;
2005                 info->numnote++;
2006         }
2007 
2008         /* Try to dump the FPU. */
2009         info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
2010                                                                info->fpu);
2011         if (info->prstatus->pr_fpvalid)
2012                 fill_note(info->notes + info->numnote++,
2013                           "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
2014 #ifdef ELF_CORE_COPY_XFPREGS
2015         if (elf_core_copy_task_xfpregs(current, info->xfpu))
2016                 fill_note(info->notes + info->numnote++,
2017                           "LINUX", ELF_CORE_XFPREG_TYPE,
2018                           sizeof(*info->xfpu), info->xfpu);
2019 #endif
2020 
2021         return 1;
2022 }
2023 
2024 static size_t get_note_info_size(struct elf_note_info *info)
2025 {
2026         int sz = 0;
2027         int i;
2028 
2029         for (i = 0; i < info->numnote; i++)
2030                 sz += notesize(info->notes + i);
2031 
2032         sz += info->thread_status_size;
2033 
2034         return sz;
2035 }
2036 
2037 static int write_note_info(struct elf_note_info *info,
2038                            struct coredump_params *cprm)
2039 {
2040         int i;
2041         struct list_head *t;
2042 
2043         for (i = 0; i < info->numnote; i++)
2044                 if (!writenote(info->notes + i, cprm))
2045                         return 0;
2046 
2047         /* write out the thread status notes section */
2048         list_for_each(t, &info->thread_list) {
2049                 struct elf_thread_status *tmp =
2050                                 list_entry(t, struct elf_thread_status, list);
2051 
2052                 for (i = 0; i < tmp->num_notes; i++)
2053                         if (!writenote(&tmp->notes[i], cprm))
2054                                 return 0;
2055         }
2056 
2057         return 1;
2058 }
2059 
2060 static void free_note_info(struct elf_note_info *info)
2061 {
2062         while (!list_empty(&info->thread_list)) {
2063                 struct list_head *tmp = info->thread_list.next;
2064                 list_del(tmp);
2065                 kfree(list_entry(tmp, struct elf_thread_status, list));
2066         }
2067 
2068         /* Free data possibly allocated by fill_files_note(): */
2069         if (info->notes_files)
2070                 vfree(info->notes_files->data);
2071 
2072         kfree(info->prstatus);
2073         kfree(info->psinfo);
2074         kfree(info->notes);
2075         kfree(info->fpu);
2076 #ifdef ELF_CORE_COPY_XFPREGS
2077         kfree(info->xfpu);
2078 #endif
2079 }
2080 
2081 #endif
2082 
2083 static struct vm_area_struct *first_vma(struct task_struct *tsk,
2084                                         struct vm_area_struct *gate_vma)
2085 {
2086         struct vm_area_struct *ret = tsk->mm->mmap;
2087 
2088         if (ret)
2089                 return ret;
2090         return gate_vma;
2091 }
2092 /*
2093  * Helper function for iterating across a vma list.  It ensures that the caller
2094  * will visit `gate_vma' prior to terminating the search.
2095  */
2096 static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
2097                                         struct vm_area_struct *gate_vma)
2098 {
2099         struct vm_area_struct *ret;
2100 
2101         ret = this_vma->vm_next;
2102         if (ret)
2103                 return ret;
2104         if (this_vma == gate_vma)
2105                 return NULL;
2106         return gate_vma;
2107 }
2108 
2109 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
2110                              elf_addr_t e_shoff, int segs)
2111 {
2112         elf->e_shoff = e_shoff;
2113         elf->e_shentsize = sizeof(*shdr4extnum);
2114         elf->e_shnum = 1;
2115         elf->e_shstrndx = SHN_UNDEF;
2116 
2117         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
2118 
2119         shdr4extnum->sh_type = SHT_NULL;
2120         shdr4extnum->sh_size = elf->e_shnum;
2121         shdr4extnum->sh_link = elf->e_shstrndx;
2122         shdr4extnum->sh_info = segs;
2123 }
2124 
2125 /*
2126  * Actual dumper
2127  *
2128  * This is a two-pass process; first we find the offsets of the bits,
2129  * and then they are actually written out.  If we run out of core limit
2130  * we just truncate.
2131  */
2132 static int elf_core_dump(struct coredump_params *cprm)
2133 {
2134         int has_dumped = 0;
2135         mm_segment_t fs;
2136         int segs, i;
2137         size_t vma_data_size = 0;
2138         struct vm_area_struct *vma, *gate_vma;
2139         struct elfhdr *elf = NULL;
2140         loff_t offset = 0, dataoff;
2141         struct elf_note_info info = { };
2142         struct elf_phdr *phdr4note = NULL;
2143         struct elf_shdr *shdr4extnum = NULL;
2144         Elf_Half e_phnum;
2145         elf_addr_t e_shoff;
2146         elf_addr_t *vma_filesz = NULL;
2147 
2148         /*
2149          * We no longer stop all VM operations.
2150          * 
2151          * This is because those proceses that could possibly change map_count
2152          * or the mmap / vma pages are now blocked in do_exit on current
2153          * finishing this core dump.
2154          *
2155          * Only ptrace can touch these memory addresses, but it doesn't change
2156          * the map_count or the pages allocated. So no possibility of crashing
2157          * exists while dumping the mm->vm_next areas to the core file.
2158          */
2159   
2160         /* alloc memory for large data structures: too large to be on stack */
2161         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
2162         if (!elf)
2163                 goto out;
2164         /*
2165          * The number of segs are recored into ELF header as 16bit value.
2166          * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
2167          */
2168         segs = current->mm->map_count;
2169         segs += elf_core_extra_phdrs();
2170 
2171         gate_vma = get_gate_vma(current->mm);
2172         if (gate_vma != NULL)
2173                 segs++;
2174 
2175         /* for notes section */
2176         segs++;
2177 
2178         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
2179          * this, kernel supports extended numbering. Have a look at
2180          * include/linux/elf.h for further information. */
2181         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
2182 
2183         /*
2184          * Collect all the non-memory information about the process for the
2185          * notes.  This also sets up the file header.
2186          */
2187         if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs))
2188                 goto cleanup;
2189 
2190         has_dumped = 1;
2191 
2192         fs = get_fs();
2193         set_fs(KERNEL_DS);
2194 
2195         offset += sizeof(*elf);                         /* Elf header */
2196         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
2197 
2198         /* Write notes phdr entry */
2199         {
2200                 size_t sz = get_note_info_size(&info);
2201 
2202                 sz += elf_coredump_extra_notes_size();
2203 
2204                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
2205                 if (!phdr4note)
2206                         goto end_coredump;
2207 
2208                 fill_elf_note_phdr(phdr4note, sz, offset);
2209                 offset += sz;
2210         }
2211 
2212         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
2213 
2214         vma_filesz = kmalloc_array(segs - 1, sizeof(*vma_filesz), GFP_KERNEL);
2215         if (!vma_filesz)
2216                 goto end_coredump;
2217 
2218         for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2219                         vma = next_vma(vma, gate_vma)) {
2220                 unsigned long dump_size;
2221 
2222                 dump_size = vma_dump_size(vma, cprm->mm_flags);
2223                 vma_filesz[i++] = dump_size;
2224                 vma_data_size += dump_size;
2225         }
2226 
2227         offset += vma_data_size;
2228         offset += elf_core_extra_data_size();
2229         e_shoff = offset;
2230 
2231         if (e_phnum == PN_XNUM) {
2232                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
2233                 if (!shdr4extnum)
2234                         goto end_coredump;
2235                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
2236         }
2237 
2238         offset = dataoff;
2239 
2240         if (!dump_emit(cprm, elf, sizeof(*elf)))
2241                 goto end_coredump;
2242 
2243         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
2244                 goto end_coredump;
2245 
2246         /* Write program headers for segments dump */
2247         for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2248                         vma = next_vma(vma, gate_vma)) {
2249                 struct elf_phdr phdr;
2250 
2251                 phdr.p_type = PT_LOAD;
2252                 phdr.p_offset = offset;
2253                 phdr.p_vaddr = vma->vm_start;
2254                 phdr.p_paddr = 0;
2255                 phdr.p_filesz = vma_filesz[i++];
2256                 phdr.p_memsz = vma->vm_end - vma->vm_start;
2257                 offset += phdr.p_filesz;
2258                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
2259                 if (vma->vm_flags & VM_WRITE)
2260                         phdr.p_flags |= PF_W;
2261                 if (vma->vm_flags & VM_EXEC)
2262                         phdr.p_flags |= PF_X;
2263                 phdr.p_align = ELF_EXEC_PAGESIZE;
2264 
2265                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
2266                         goto end_coredump;
2267         }
2268 
2269         if (!elf_core_write_extra_phdrs(cprm, offset))
2270                 goto end_coredump;
2271 
2272         /* write out the notes section */
2273         if (!write_note_info(&info, cprm))
2274                 goto end_coredump;
2275 
2276         if (elf_coredump_extra_notes_write(cprm))
2277                 goto end_coredump;
2278 
2279         /* Align to page */
2280         if (!dump_skip(cprm, dataoff - cprm->pos))
2281                 goto end_coredump;
2282 
2283         for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2284                         vma = next_vma(vma, gate_vma)) {
2285                 unsigned long addr;
2286                 unsigned long end;
2287 
2288                 end = vma->vm_start + vma_filesz[i++];
2289 
2290                 for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
2291                         struct page *page;
2292                         int stop;
2293 
2294                         page = get_dump_page(addr);
2295                         if (page) {
2296                                 void *kaddr = kmap(page);
2297                                 stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
2298                                 kunmap(page);
2299                                 put_page(page);
2300                         } else
2301                                 stop = !dump_skip(cprm, PAGE_SIZE);
2302                         if (stop)
2303                                 goto end_coredump;
2304                 }
2305         }
2306 
2307         if (!elf_core_write_extra_data(cprm))
2308                 goto end_coredump;
2309 
2310         if (e_phnum == PN_XNUM) {
2311                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
2312                         goto end_coredump;
2313         }
2314 
2315 end_coredump:
2316         set_fs(fs);
2317 
2318 cleanup:
2319         free_note_info(&info);
2320         kfree(shdr4extnum);
2321         kfree(vma_filesz);
2322         kfree(phdr4note);
2323         kfree(elf);
2324 out:
2325         return has_dumped;
2326 }
2327 
2328 #endif          /* CONFIG_ELF_CORE */
2329 
2330 static int __init init_elf_binfmt(void)
2331 {
2332         register_binfmt(&elf_format);
2333         return 0;
2334 }
2335 
2336 static void __exit exit_elf_binfmt(void)
2337 {
2338         /* Remove the COFF and ELF loaders. */
2339         unregister_binfmt(&elf_format);
2340 }
2341 
2342 core_initcall(init_elf_binfmt);
2343 module_exit(exit_elf_binfmt);
2344 MODULE_LICENSE("GPL");
2345 

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