Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/fs/binfmt_elf_fdpic.c

  1 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
  2  *
  3  * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
  4  * Written by David Howells (dhowells@redhat.com)
  5  * Derived from binfmt_elf.c
  6  *
  7  * This program is free software; you can redistribute it and/or
  8  * modify it under the terms of the GNU General Public License
  9  * as published by the Free Software Foundation; either version
 10  * 2 of the License, or (at your option) any later version.
 11  */
 12 
 13 #include <linux/module.h>
 14 
 15 #include <linux/fs.h>
 16 #include <linux/stat.h>
 17 #include <linux/sched.h>
 18 #include <linux/mm.h>
 19 #include <linux/mman.h>
 20 #include <linux/errno.h>
 21 #include <linux/signal.h>
 22 #include <linux/binfmts.h>
 23 #include <linux/string.h>
 24 #include <linux/file.h>
 25 #include <linux/fcntl.h>
 26 #include <linux/slab.h>
 27 #include <linux/pagemap.h>
 28 #include <linux/security.h>
 29 #include <linux/highmem.h>
 30 #include <linux/highuid.h>
 31 #include <linux/personality.h>
 32 #include <linux/ptrace.h>
 33 #include <linux/init.h>
 34 #include <linux/elf.h>
 35 #include <linux/elf-fdpic.h>
 36 #include <linux/elfcore.h>
 37 #include <linux/coredump.h>
 38 #include <linux/dax.h>
 39 
 40 #include <linux/uaccess.h>
 41 #include <asm/param.h>
 42 #include <asm/pgalloc.h>
 43 
 44 typedef char *elf_caddr_t;
 45 
 46 #if 0
 47 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
 48 #else
 49 #define kdebug(fmt, ...) do {} while(0)
 50 #endif
 51 
 52 #if 0
 53 #define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
 54 #else
 55 #define kdcore(fmt, ...) do {} while(0)
 56 #endif
 57 
 58 MODULE_LICENSE("GPL");
 59 
 60 static int load_elf_fdpic_binary(struct linux_binprm *);
 61 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
 62 static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
 63                               struct mm_struct *, const char *);
 64 
 65 static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
 66                                    struct elf_fdpic_params *,
 67                                    struct elf_fdpic_params *);
 68 
 69 #ifndef CONFIG_MMU
 70 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
 71                                                    struct file *,
 72                                                    struct mm_struct *);
 73 #endif
 74 
 75 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
 76                                              struct file *, struct mm_struct *);
 77 
 78 #ifdef CONFIG_ELF_CORE
 79 static int elf_fdpic_core_dump(struct coredump_params *cprm);
 80 #endif
 81 
 82 static struct linux_binfmt elf_fdpic_format = {
 83         .module         = THIS_MODULE,
 84         .load_binary    = load_elf_fdpic_binary,
 85 #ifdef CONFIG_ELF_CORE
 86         .core_dump      = elf_fdpic_core_dump,
 87 #endif
 88         .min_coredump   = ELF_EXEC_PAGESIZE,
 89 };
 90 
 91 static int __init init_elf_fdpic_binfmt(void)
 92 {
 93         register_binfmt(&elf_fdpic_format);
 94         return 0;
 95 }
 96 
 97 static void __exit exit_elf_fdpic_binfmt(void)
 98 {
 99         unregister_binfmt(&elf_fdpic_format);
100 }
101 
102 core_initcall(init_elf_fdpic_binfmt);
103 module_exit(exit_elf_fdpic_binfmt);
104 
105 static int is_elf(struct elfhdr *hdr, struct file *file)
106 {
107         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
108                 return 0;
109         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
110                 return 0;
111         if (!elf_check_arch(hdr))
112                 return 0;
113         if (!file->f_op->mmap)
114                 return 0;
115         return 1;
116 }
117 
118 #ifndef elf_check_fdpic
119 #define elf_check_fdpic(x) 0
120 #endif
121 
122 #ifndef elf_check_const_displacement
123 #define elf_check_const_displacement(x) 0
124 #endif
125 
126 static int is_constdisp(struct elfhdr *hdr)
127 {
128         if (!elf_check_fdpic(hdr))
129                 return 1;
130         if (elf_check_const_displacement(hdr))
131                 return 1;
132         return 0;
133 }
134 
135 /*****************************************************************************/
136 /*
137  * read the program headers table into memory
138  */
139 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
140                                  struct file *file)
141 {
142         struct elf32_phdr *phdr;
143         unsigned long size;
144         int retval, loop;
145 
146         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
147                 return -ENOMEM;
148         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
149                 return -ENOMEM;
150 
151         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
152         params->phdrs = kmalloc(size, GFP_KERNEL);
153         if (!params->phdrs)
154                 return -ENOMEM;
155 
156         retval = kernel_read(file, params->hdr.e_phoff,
157                              (char *) params->phdrs, size);
158         if (unlikely(retval != size))
159                 return retval < 0 ? retval : -ENOEXEC;
160 
161         /* determine stack size for this binary */
162         phdr = params->phdrs;
163         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
164                 if (phdr->p_type != PT_GNU_STACK)
165                         continue;
166 
167                 if (phdr->p_flags & PF_X)
168                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
169                 else
170                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
171 
172                 params->stack_size = phdr->p_memsz;
173                 break;
174         }
175 
176         return 0;
177 }
178 
179 /*****************************************************************************/
180 /*
181  * load an fdpic binary into various bits of memory
182  */
183 static int load_elf_fdpic_binary(struct linux_binprm *bprm)
184 {
185         struct elf_fdpic_params exec_params, interp_params;
186         struct pt_regs *regs = current_pt_regs();
187         struct elf_phdr *phdr;
188         unsigned long stack_size, entryaddr;
189 #ifdef ELF_FDPIC_PLAT_INIT
190         unsigned long dynaddr;
191 #endif
192 #ifndef CONFIG_MMU
193         unsigned long stack_prot;
194 #endif
195         struct file *interpreter = NULL; /* to shut gcc up */
196         char *interpreter_name = NULL;
197         int executable_stack;
198         int retval, i;
199 
200         kdebug("____ LOAD %d ____", current->pid);
201 
202         memset(&exec_params, 0, sizeof(exec_params));
203         memset(&interp_params, 0, sizeof(interp_params));
204 
205         exec_params.hdr = *(struct elfhdr *) bprm->buf;
206         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
207 
208         /* check that this is a binary we know how to deal with */
209         retval = -ENOEXEC;
210         if (!is_elf(&exec_params.hdr, bprm->file))
211                 goto error;
212         if (!elf_check_fdpic(&exec_params.hdr)) {
213 #ifdef CONFIG_MMU
214                 /* binfmt_elf handles non-fdpic elf except on nommu */
215                 goto error;
216 #else
217                 /* nommu can only load ET_DYN (PIE) ELF */
218                 if (exec_params.hdr.e_type != ET_DYN)
219                         goto error;
220 #endif
221         }
222 
223         /* read the program header table */
224         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
225         if (retval < 0)
226                 goto error;
227 
228         /* scan for a program header that specifies an interpreter */
229         phdr = exec_params.phdrs;
230 
231         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
232                 switch (phdr->p_type) {
233                 case PT_INTERP:
234                         retval = -ENOMEM;
235                         if (phdr->p_filesz > PATH_MAX)
236                                 goto error;
237                         retval = -ENOENT;
238                         if (phdr->p_filesz < 2)
239                                 goto error;
240 
241                         /* read the name of the interpreter into memory */
242                         interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
243                         if (!interpreter_name)
244                                 goto error;
245 
246                         retval = kernel_read(bprm->file,
247                                              phdr->p_offset,
248                                              interpreter_name,
249                                              phdr->p_filesz);
250                         if (unlikely(retval != phdr->p_filesz)) {
251                                 if (retval >= 0)
252                                         retval = -ENOEXEC;
253                                 goto error;
254                         }
255 
256                         retval = -ENOENT;
257                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
258                                 goto error;
259 
260                         kdebug("Using ELF interpreter %s", interpreter_name);
261 
262                         /* replace the program with the interpreter */
263                         interpreter = open_exec(interpreter_name);
264                         retval = PTR_ERR(interpreter);
265                         if (IS_ERR(interpreter)) {
266                                 interpreter = NULL;
267                                 goto error;
268                         }
269 
270                         /*
271                          * If the binary is not readable then enforce
272                          * mm->dumpable = 0 regardless of the interpreter's
273                          * permissions.
274                          */
275                         would_dump(bprm, interpreter);
276 
277                         retval = kernel_read(interpreter, 0, bprm->buf,
278                                              BINPRM_BUF_SIZE);
279                         if (unlikely(retval != BINPRM_BUF_SIZE)) {
280                                 if (retval >= 0)
281                                         retval = -ENOEXEC;
282                                 goto error;
283                         }
284 
285                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
286                         break;
287 
288                 case PT_LOAD:
289 #ifdef CONFIG_MMU
290                         if (exec_params.load_addr == 0)
291                                 exec_params.load_addr = phdr->p_vaddr;
292 #endif
293                         break;
294                 }
295 
296         }
297 
298         if (is_constdisp(&exec_params.hdr))
299                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
300 
301         /* perform insanity checks on the interpreter */
302         if (interpreter_name) {
303                 retval = -ELIBBAD;
304                 if (!is_elf(&interp_params.hdr, interpreter))
305                         goto error;
306 
307                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
308 
309                 /* read the interpreter's program header table */
310                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
311                 if (retval < 0)
312                         goto error;
313         }
314 
315         stack_size = exec_params.stack_size;
316         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
317                 executable_stack = EXSTACK_ENABLE_X;
318         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
319                 executable_stack = EXSTACK_DISABLE_X;
320         else
321                 executable_stack = EXSTACK_DEFAULT;
322 
323         if (stack_size == 0) {
324                 stack_size = interp_params.stack_size;
325                 if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
326                         executable_stack = EXSTACK_ENABLE_X;
327                 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
328                         executable_stack = EXSTACK_DISABLE_X;
329                 else
330                         executable_stack = EXSTACK_DEFAULT;
331         }
332 
333         retval = -ENOEXEC;
334         if (stack_size == 0)
335                 stack_size = 131072UL; /* same as exec.c's default commit */
336 
337         if (is_constdisp(&interp_params.hdr))
338                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
339 
340         /* flush all traces of the currently running executable */
341         retval = flush_old_exec(bprm);
342         if (retval)
343                 goto error;
344 
345         /* there's now no turning back... the old userspace image is dead,
346          * defunct, deceased, etc.
347          */
348         if (elf_check_fdpic(&exec_params.hdr))
349                 set_personality(PER_LINUX_FDPIC);
350         else
351                 set_personality(PER_LINUX);
352         if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
353                 current->personality |= READ_IMPLIES_EXEC;
354 
355         setup_new_exec(bprm);
356 
357         set_binfmt(&elf_fdpic_format);
358 
359         current->mm->start_code = 0;
360         current->mm->end_code = 0;
361         current->mm->start_stack = 0;
362         current->mm->start_data = 0;
363         current->mm->end_data = 0;
364         current->mm->context.exec_fdpic_loadmap = 0;
365         current->mm->context.interp_fdpic_loadmap = 0;
366 
367 #ifdef CONFIG_MMU
368         elf_fdpic_arch_lay_out_mm(&exec_params,
369                                   &interp_params,
370                                   &current->mm->start_stack,
371                                   &current->mm->start_brk);
372 
373         retval = setup_arg_pages(bprm, current->mm->start_stack,
374                                  executable_stack);
375         if (retval < 0)
376                 goto error;
377 #endif
378 
379         /* load the executable and interpreter into memory */
380         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
381                                     "executable");
382         if (retval < 0)
383                 goto error;
384 
385         if (interpreter_name) {
386                 retval = elf_fdpic_map_file(&interp_params, interpreter,
387                                             current->mm, "interpreter");
388                 if (retval < 0) {
389                         printk(KERN_ERR "Unable to load interpreter\n");
390                         goto error;
391                 }
392 
393                 allow_write_access(interpreter);
394                 fput(interpreter);
395                 interpreter = NULL;
396         }
397 
398 #ifdef CONFIG_MMU
399         if (!current->mm->start_brk)
400                 current->mm->start_brk = current->mm->end_data;
401 
402         current->mm->brk = current->mm->start_brk =
403                 PAGE_ALIGN(current->mm->start_brk);
404 
405 #else
406         /* create a stack area and zero-size brk area */
407         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
408         if (stack_size < PAGE_SIZE * 2)
409                 stack_size = PAGE_SIZE * 2;
410 
411         stack_prot = PROT_READ | PROT_WRITE;
412         if (executable_stack == EXSTACK_ENABLE_X ||
413             (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
414                 stack_prot |= PROT_EXEC;
415 
416         current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
417                                          MAP_PRIVATE | MAP_ANONYMOUS |
418                                          MAP_UNINITIALIZED | MAP_GROWSDOWN,
419                                          0);
420 
421         if (IS_ERR_VALUE(current->mm->start_brk)) {
422                 retval = current->mm->start_brk;
423                 current->mm->start_brk = 0;
424                 goto error;
425         }
426 
427         current->mm->brk = current->mm->start_brk;
428         current->mm->context.end_brk = current->mm->start_brk;
429         current->mm->start_stack = current->mm->start_brk + stack_size;
430 #endif
431 
432         install_exec_creds(bprm);
433         if (create_elf_fdpic_tables(bprm, current->mm,
434                                     &exec_params, &interp_params) < 0)
435                 goto error;
436 
437         kdebug("- start_code  %lx", current->mm->start_code);
438         kdebug("- end_code    %lx", current->mm->end_code);
439         kdebug("- start_data  %lx", current->mm->start_data);
440         kdebug("- end_data    %lx", current->mm->end_data);
441         kdebug("- start_brk   %lx", current->mm->start_brk);
442         kdebug("- brk         %lx", current->mm->brk);
443         kdebug("- start_stack %lx", current->mm->start_stack);
444 
445 #ifdef ELF_FDPIC_PLAT_INIT
446         /*
447          * The ABI may specify that certain registers be set up in special
448          * ways (on i386 %edx is the address of a DT_FINI function, for
449          * example.  This macro performs whatever initialization to
450          * the regs structure is required.
451          */
452         dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
453         ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
454                             dynaddr);
455 #endif
456 
457         /* everything is now ready... get the userspace context ready to roll */
458         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
459         start_thread(regs, entryaddr, current->mm->start_stack);
460 
461         retval = 0;
462 
463 error:
464         if (interpreter) {
465                 allow_write_access(interpreter);
466                 fput(interpreter);
467         }
468         kfree(interpreter_name);
469         kfree(exec_params.phdrs);
470         kfree(exec_params.loadmap);
471         kfree(interp_params.phdrs);
472         kfree(interp_params.loadmap);
473         return retval;
474 }
475 
476 /*****************************************************************************/
477 
478 #ifndef ELF_BASE_PLATFORM
479 /*
480  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
481  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
482  * will be copied to the user stack in the same manner as AT_PLATFORM.
483  */
484 #define ELF_BASE_PLATFORM NULL
485 #endif
486 
487 /*
488  * present useful information to the program by shovelling it onto the new
489  * process's stack
490  */
491 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
492                                    struct mm_struct *mm,
493                                    struct elf_fdpic_params *exec_params,
494                                    struct elf_fdpic_params *interp_params)
495 {
496         const struct cred *cred = current_cred();
497         unsigned long sp, csp, nitems;
498         elf_caddr_t __user *argv, *envp;
499         size_t platform_len = 0, len;
500         char *k_platform, *k_base_platform;
501         char __user *u_platform, *u_base_platform, *p;
502         int loop;
503         int nr; /* reset for each csp adjustment */
504 
505 #ifdef CONFIG_MMU
506         /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
507          * by the processes running on the same package. One thing we can do is
508          * to shuffle the initial stack for them, so we give the architecture
509          * an opportunity to do so here.
510          */
511         sp = arch_align_stack(bprm->p);
512 #else
513         sp = mm->start_stack;
514 
515         /* stack the program arguments and environment */
516         if (transfer_args_to_stack(bprm, &sp) < 0)
517                 return -EFAULT;
518         sp &= ~15;
519 #endif
520 
521         /*
522          * If this architecture has a platform capability string, copy it
523          * to userspace.  In some cases (Sparc), this info is impossible
524          * for userspace to get any other way, in others (i386) it is
525          * merely difficult.
526          */
527         k_platform = ELF_PLATFORM;
528         u_platform = NULL;
529 
530         if (k_platform) {
531                 platform_len = strlen(k_platform) + 1;
532                 sp -= platform_len;
533                 u_platform = (char __user *) sp;
534                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
535                         return -EFAULT;
536         }
537 
538         /*
539          * If this architecture has a "base" platform capability
540          * string, copy it to userspace.
541          */
542         k_base_platform = ELF_BASE_PLATFORM;
543         u_base_platform = NULL;
544 
545         if (k_base_platform) {
546                 platform_len = strlen(k_base_platform) + 1;
547                 sp -= platform_len;
548                 u_base_platform = (char __user *) sp;
549                 if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
550                         return -EFAULT;
551         }
552 
553         sp &= ~7UL;
554 
555         /* stack the load map(s) */
556         len = sizeof(struct elf32_fdpic_loadmap);
557         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
558         sp = (sp - len) & ~7UL;
559         exec_params->map_addr = sp;
560 
561         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
562                 return -EFAULT;
563 
564         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
565 
566         if (interp_params->loadmap) {
567                 len = sizeof(struct elf32_fdpic_loadmap);
568                 len += sizeof(struct elf32_fdpic_loadseg) *
569                         interp_params->loadmap->nsegs;
570                 sp = (sp - len) & ~7UL;
571                 interp_params->map_addr = sp;
572 
573                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
574                                  len) != 0)
575                         return -EFAULT;
576 
577                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
578         }
579 
580         /* force 16 byte _final_ alignment here for generality */
581 #define DLINFO_ITEMS 15
582 
583         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
584                 (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
585 
586         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
587                 nitems++;
588 
589         csp = sp;
590         sp -= nitems * 2 * sizeof(unsigned long);
591         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
592         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
593         sp -= 1 * sizeof(unsigned long);                /* argc */
594 
595         csp -= sp & 15UL;
596         sp -= sp & 15UL;
597 
598         /* put the ELF interpreter info on the stack */
599 #define NEW_AUX_ENT(id, val)                                            \
600         do {                                                            \
601                 struct { unsigned long _id, _val; } __user *ent;        \
602                                                                         \
603                 ent = (void __user *) csp;                              \
604                 __put_user((id), &ent[nr]._id);                         \
605                 __put_user((val), &ent[nr]._val);                       \
606                 nr++;                                                   \
607         } while (0)
608 
609         nr = 0;
610         csp -= 2 * sizeof(unsigned long);
611         NEW_AUX_ENT(AT_NULL, 0);
612         if (k_platform) {
613                 nr = 0;
614                 csp -= 2 * sizeof(unsigned long);
615                 NEW_AUX_ENT(AT_PLATFORM,
616                             (elf_addr_t) (unsigned long) u_platform);
617         }
618 
619         if (k_base_platform) {
620                 nr = 0;
621                 csp -= 2 * sizeof(unsigned long);
622                 NEW_AUX_ENT(AT_BASE_PLATFORM,
623                             (elf_addr_t) (unsigned long) u_base_platform);
624         }
625 
626         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
627                 nr = 0;
628                 csp -= 2 * sizeof(unsigned long);
629                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
630         }
631 
632         nr = 0;
633         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
634         NEW_AUX_ENT(AT_HWCAP,   ELF_HWCAP);
635 #ifdef ELF_HWCAP2
636         NEW_AUX_ENT(AT_HWCAP2,  ELF_HWCAP2);
637 #endif
638         NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
639         NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
640         NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
641         NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
642         NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
643         NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
644         NEW_AUX_ENT(AT_FLAGS,   0);
645         NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
646         NEW_AUX_ENT(AT_UID,     (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
647         NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
648         NEW_AUX_ENT(AT_GID,     (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
649         NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
650         NEW_AUX_ENT(AT_SECURE,  security_bprm_secureexec(bprm));
651         NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
652 
653 #ifdef ARCH_DLINFO
654         nr = 0;
655         csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
656 
657         /* ARCH_DLINFO must come last so platform specific code can enforce
658          * special alignment requirements on the AUXV if necessary (eg. PPC).
659          */
660         ARCH_DLINFO;
661 #endif
662 #undef NEW_AUX_ENT
663 
664         /* allocate room for argv[] and envv[] */
665         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
666         envp = (elf_caddr_t __user *) csp;
667         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
668         argv = (elf_caddr_t __user *) csp;
669 
670         /* stack argc */
671         csp -= sizeof(unsigned long);
672         __put_user(bprm->argc, (unsigned long __user *) csp);
673 
674         BUG_ON(csp != sp);
675 
676         /* fill in the argv[] array */
677 #ifdef CONFIG_MMU
678         current->mm->arg_start = bprm->p;
679 #else
680         current->mm->arg_start = current->mm->start_stack -
681                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
682 #endif
683 
684         p = (char __user *) current->mm->arg_start;
685         for (loop = bprm->argc; loop > 0; loop--) {
686                 __put_user((elf_caddr_t) p, argv++);
687                 len = strnlen_user(p, MAX_ARG_STRLEN);
688                 if (!len || len > MAX_ARG_STRLEN)
689                         return -EINVAL;
690                 p += len;
691         }
692         __put_user(NULL, argv);
693         current->mm->arg_end = (unsigned long) p;
694 
695         /* fill in the envv[] array */
696         current->mm->env_start = (unsigned long) p;
697         for (loop = bprm->envc; loop > 0; loop--) {
698                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
699                 len = strnlen_user(p, MAX_ARG_STRLEN);
700                 if (!len || len > MAX_ARG_STRLEN)
701                         return -EINVAL;
702                 p += len;
703         }
704         __put_user(NULL, envp);
705         current->mm->env_end = (unsigned long) p;
706 
707         mm->start_stack = (unsigned long) sp;
708         return 0;
709 }
710 
711 /*****************************************************************************/
712 /*
713  * load the appropriate binary image (executable or interpreter) into memory
714  * - we assume no MMU is available
715  * - if no other PIC bits are set in params->hdr->e_flags
716  *   - we assume that the LOADable segments in the binary are independently relocatable
717  *   - we assume R/O executable segments are shareable
718  * - else
719  *   - we assume the loadable parts of the image to require fixed displacement
720  *   - the image is not shareable
721  */
722 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
723                               struct file *file,
724                               struct mm_struct *mm,
725                               const char *what)
726 {
727         struct elf32_fdpic_loadmap *loadmap;
728 #ifdef CONFIG_MMU
729         struct elf32_fdpic_loadseg *mseg;
730 #endif
731         struct elf32_fdpic_loadseg *seg;
732         struct elf32_phdr *phdr;
733         unsigned long load_addr, stop;
734         unsigned nloads, tmp;
735         size_t size;
736         int loop, ret;
737 
738         /* allocate a load map table */
739         nloads = 0;
740         for (loop = 0; loop < params->hdr.e_phnum; loop++)
741                 if (params->phdrs[loop].p_type == PT_LOAD)
742                         nloads++;
743 
744         if (nloads == 0)
745                 return -ELIBBAD;
746 
747         size = sizeof(*loadmap) + nloads * sizeof(*seg);
748         loadmap = kzalloc(size, GFP_KERNEL);
749         if (!loadmap)
750                 return -ENOMEM;
751 
752         params->loadmap = loadmap;
753 
754         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
755         loadmap->nsegs = nloads;
756 
757         load_addr = params->load_addr;
758         seg = loadmap->segs;
759 
760         /* map the requested LOADs into the memory space */
761         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
762         case ELF_FDPIC_FLAG_CONSTDISP:
763         case ELF_FDPIC_FLAG_CONTIGUOUS:
764 #ifndef CONFIG_MMU
765                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
766                 if (ret < 0)
767                         return ret;
768                 break;
769 #endif
770         default:
771                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
772                 if (ret < 0)
773                         return ret;
774                 break;
775         }
776 
777         /* map the entry point */
778         if (params->hdr.e_entry) {
779                 seg = loadmap->segs;
780                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
781                         if (params->hdr.e_entry >= seg->p_vaddr &&
782                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
783                                 params->entry_addr =
784                                         (params->hdr.e_entry - seg->p_vaddr) +
785                                         seg->addr;
786                                 break;
787                         }
788                 }
789         }
790 
791         /* determine where the program header table has wound up if mapped */
792         stop = params->hdr.e_phoff;
793         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
794         phdr = params->phdrs;
795 
796         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
797                 if (phdr->p_type != PT_LOAD)
798                         continue;
799 
800                 if (phdr->p_offset > params->hdr.e_phoff ||
801                     phdr->p_offset + phdr->p_filesz < stop)
802                         continue;
803 
804                 seg = loadmap->segs;
805                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
806                         if (phdr->p_vaddr >= seg->p_vaddr &&
807                             phdr->p_vaddr + phdr->p_filesz <=
808                             seg->p_vaddr + seg->p_memsz) {
809                                 params->ph_addr =
810                                         (phdr->p_vaddr - seg->p_vaddr) +
811                                         seg->addr +
812                                         params->hdr.e_phoff - phdr->p_offset;
813                                 break;
814                         }
815                 }
816                 break;
817         }
818 
819         /* determine where the dynamic section has wound up if there is one */
820         phdr = params->phdrs;
821         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
822                 if (phdr->p_type != PT_DYNAMIC)
823                         continue;
824 
825                 seg = loadmap->segs;
826                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
827                         if (phdr->p_vaddr >= seg->p_vaddr &&
828                             phdr->p_vaddr + phdr->p_memsz <=
829                             seg->p_vaddr + seg->p_memsz) {
830                                 params->dynamic_addr =
831                                         (phdr->p_vaddr - seg->p_vaddr) +
832                                         seg->addr;
833 
834                                 /* check the dynamic section contains at least
835                                  * one item, and that the last item is a NULL
836                                  * entry */
837                                 if (phdr->p_memsz == 0 ||
838                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
839                                         goto dynamic_error;
840 
841                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
842                                 if (((Elf32_Dyn *)
843                                      params->dynamic_addr)[tmp - 1].d_tag != 0)
844                                         goto dynamic_error;
845                                 break;
846                         }
847                 }
848                 break;
849         }
850 
851         /* now elide adjacent segments in the load map on MMU linux
852          * - on uClinux the holes between may actually be filled with system
853          *   stuff or stuff from other processes
854          */
855 #ifdef CONFIG_MMU
856         nloads = loadmap->nsegs;
857         mseg = loadmap->segs;
858         seg = mseg + 1;
859         for (loop = 1; loop < nloads; loop++) {
860                 /* see if we have a candidate for merging */
861                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
862                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
863                         if (load_addr == (seg->addr & PAGE_MASK)) {
864                                 mseg->p_memsz +=
865                                         load_addr -
866                                         (mseg->addr + mseg->p_memsz);
867                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
868                                 mseg->p_memsz += seg->p_memsz;
869                                 loadmap->nsegs--;
870                                 continue;
871                         }
872                 }
873 
874                 mseg++;
875                 if (mseg != seg)
876                         *mseg = *seg;
877         }
878 #endif
879 
880         kdebug("Mapped Object [%s]:", what);
881         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
882         kdebug("- entry    : %lx", params->entry_addr);
883         kdebug("- PHDR[]   : %lx", params->ph_addr);
884         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
885         seg = loadmap->segs;
886         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
887                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
888                        loop,
889                        seg->addr, seg->addr + seg->p_memsz - 1,
890                        seg->p_vaddr, seg->p_memsz);
891 
892         return 0;
893 
894 dynamic_error:
895         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
896                what, file_inode(file)->i_ino);
897         return -ELIBBAD;
898 }
899 
900 /*****************************************************************************/
901 /*
902  * map a file with constant displacement under uClinux
903  */
904 #ifndef CONFIG_MMU
905 static int elf_fdpic_map_file_constdisp_on_uclinux(
906         struct elf_fdpic_params *params,
907         struct file *file,
908         struct mm_struct *mm)
909 {
910         struct elf32_fdpic_loadseg *seg;
911         struct elf32_phdr *phdr;
912         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
913         int loop, ret;
914 
915         load_addr = params->load_addr;
916         seg = params->loadmap->segs;
917 
918         /* determine the bounds of the contiguous overall allocation we must
919          * make */
920         phdr = params->phdrs;
921         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
922                 if (params->phdrs[loop].p_type != PT_LOAD)
923                         continue;
924 
925                 if (base > phdr->p_vaddr)
926                         base = phdr->p_vaddr;
927                 if (top < phdr->p_vaddr + phdr->p_memsz)
928                         top = phdr->p_vaddr + phdr->p_memsz;
929         }
930 
931         /* allocate one big anon block for everything */
932         mflags = MAP_PRIVATE;
933         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
934                 mflags |= MAP_EXECUTABLE;
935 
936         maddr = vm_mmap(NULL, load_addr, top - base,
937                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
938         if (IS_ERR_VALUE(maddr))
939                 return (int) maddr;
940 
941         if (load_addr != 0)
942                 load_addr += PAGE_ALIGN(top - base);
943 
944         /* and then load the file segments into it */
945         phdr = params->phdrs;
946         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
947                 if (params->phdrs[loop].p_type != PT_LOAD)
948                         continue;
949 
950                 seg->addr = maddr + (phdr->p_vaddr - base);
951                 seg->p_vaddr = phdr->p_vaddr;
952                 seg->p_memsz = phdr->p_memsz;
953 
954                 ret = read_code(file, seg->addr, phdr->p_offset,
955                                        phdr->p_filesz);
956                 if (ret < 0)
957                         return ret;
958 
959                 /* map the ELF header address if in this segment */
960                 if (phdr->p_offset == 0)
961                         params->elfhdr_addr = seg->addr;
962 
963                 /* clear any space allocated but not loaded */
964                 if (phdr->p_filesz < phdr->p_memsz) {
965                         if (clear_user((void *) (seg->addr + phdr->p_filesz),
966                                        phdr->p_memsz - phdr->p_filesz))
967                                 return -EFAULT;
968                 }
969 
970                 if (mm) {
971                         if (phdr->p_flags & PF_X) {
972                                 if (!mm->start_code) {
973                                         mm->start_code = seg->addr;
974                                         mm->end_code = seg->addr +
975                                                 phdr->p_memsz;
976                                 }
977                         } else if (!mm->start_data) {
978                                 mm->start_data = seg->addr;
979                                 mm->end_data = seg->addr + phdr->p_memsz;
980                         }
981                 }
982 
983                 seg++;
984         }
985 
986         return 0;
987 }
988 #endif
989 
990 /*****************************************************************************/
991 /*
992  * map a binary by direct mmap() of the individual PT_LOAD segments
993  */
994 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
995                                              struct file *file,
996                                              struct mm_struct *mm)
997 {
998         struct elf32_fdpic_loadseg *seg;
999         struct elf32_phdr *phdr;
1000         unsigned long load_addr, delta_vaddr;
1001         int loop, dvset;
1002 
1003         load_addr = params->load_addr;
1004         delta_vaddr = 0;
1005         dvset = 0;
1006 
1007         seg = params->loadmap->segs;
1008 
1009         /* deal with each load segment separately */
1010         phdr = params->phdrs;
1011         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1012                 unsigned long maddr, disp, excess, excess1;
1013                 int prot = 0, flags;
1014 
1015                 if (phdr->p_type != PT_LOAD)
1016                         continue;
1017 
1018                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1019                        (unsigned long) phdr->p_vaddr,
1020                        (unsigned long) phdr->p_offset,
1021                        (unsigned long) phdr->p_filesz,
1022                        (unsigned long) phdr->p_memsz);
1023 
1024                 /* determine the mapping parameters */
1025                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1026                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1027                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1028 
1029                 flags = MAP_PRIVATE | MAP_DENYWRITE;
1030                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1031                         flags |= MAP_EXECUTABLE;
1032 
1033                 maddr = 0;
1034 
1035                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1036                 case ELF_FDPIC_FLAG_INDEPENDENT:
1037                         /* PT_LOADs are independently locatable */
1038                         break;
1039 
1040                 case ELF_FDPIC_FLAG_HONOURVADDR:
1041                         /* the specified virtual address must be honoured */
1042                         maddr = phdr->p_vaddr;
1043                         flags |= MAP_FIXED;
1044                         break;
1045 
1046                 case ELF_FDPIC_FLAG_CONSTDISP:
1047                         /* constant displacement
1048                          * - can be mapped anywhere, but must be mapped as a
1049                          *   unit
1050                          */
1051                         if (!dvset) {
1052                                 maddr = load_addr;
1053                                 delta_vaddr = phdr->p_vaddr;
1054                                 dvset = 1;
1055                         } else {
1056                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1057                                 flags |= MAP_FIXED;
1058                         }
1059                         break;
1060 
1061                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1062                         /* contiguity handled later */
1063                         break;
1064 
1065                 default:
1066                         BUG();
1067                 }
1068 
1069                 maddr &= PAGE_MASK;
1070 
1071                 /* create the mapping */
1072                 disp = phdr->p_vaddr & ~PAGE_MASK;
1073                 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1074                                 phdr->p_offset - disp);
1075 
1076                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1077                        loop, phdr->p_memsz + disp, prot, flags,
1078                        phdr->p_offset - disp, maddr);
1079 
1080                 if (IS_ERR_VALUE(maddr))
1081                         return (int) maddr;
1082 
1083                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1084                     ELF_FDPIC_FLAG_CONTIGUOUS)
1085                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1086 
1087                 seg->addr = maddr + disp;
1088                 seg->p_vaddr = phdr->p_vaddr;
1089                 seg->p_memsz = phdr->p_memsz;
1090 
1091                 /* map the ELF header address if in this segment */
1092                 if (phdr->p_offset == 0)
1093                         params->elfhdr_addr = seg->addr;
1094 
1095                 /* clear the bit between beginning of mapping and beginning of
1096                  * PT_LOAD */
1097                 if (prot & PROT_WRITE && disp > 0) {
1098                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1099                         if (clear_user((void __user *) maddr, disp))
1100                                 return -EFAULT;
1101                         maddr += disp;
1102                 }
1103 
1104                 /* clear any space allocated but not loaded
1105                  * - on uClinux we can just clear the lot
1106                  * - on MMU linux we'll get a SIGBUS beyond the last page
1107                  *   extant in the file
1108                  */
1109                 excess = phdr->p_memsz - phdr->p_filesz;
1110                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1111 
1112 #ifdef CONFIG_MMU
1113                 if (excess > excess1) {
1114                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1115                         unsigned long xmaddr;
1116 
1117                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1118                         xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1119                                          prot, flags, 0);
1120 
1121                         kdebug("mmap[%d] <anon>"
1122                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1123                                loop, xaddr, excess - excess1, prot, flags,
1124                                xmaddr);
1125 
1126                         if (xmaddr != xaddr)
1127                                 return -ENOMEM;
1128                 }
1129 
1130                 if (prot & PROT_WRITE && excess1 > 0) {
1131                         kdebug("clear[%d] ad=%lx sz=%lx",
1132                                loop, maddr + phdr->p_filesz, excess1);
1133                         if (clear_user((void __user *) maddr + phdr->p_filesz,
1134                                        excess1))
1135                                 return -EFAULT;
1136                 }
1137 
1138 #else
1139                 if (excess > 0) {
1140                         kdebug("clear[%d] ad=%lx sz=%lx",
1141                                loop, maddr + phdr->p_filesz, excess);
1142                         if (clear_user((void *) maddr + phdr->p_filesz, excess))
1143                                 return -EFAULT;
1144                 }
1145 #endif
1146 
1147                 if (mm) {
1148                         if (phdr->p_flags & PF_X) {
1149                                 if (!mm->start_code) {
1150                                         mm->start_code = maddr;
1151                                         mm->end_code = maddr + phdr->p_memsz;
1152                                 }
1153                         } else if (!mm->start_data) {
1154                                 mm->start_data = maddr;
1155                                 mm->end_data = maddr + phdr->p_memsz;
1156                         }
1157                 }
1158 
1159                 seg++;
1160         }
1161 
1162         return 0;
1163 }
1164 
1165 /*****************************************************************************/
1166 /*
1167  * ELF-FDPIC core dumper
1168  *
1169  * Modelled on fs/exec.c:aout_core_dump()
1170  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1171  *
1172  * Modelled on fs/binfmt_elf.c core dumper
1173  */
1174 #ifdef CONFIG_ELF_CORE
1175 
1176 /*
1177  * Decide whether a segment is worth dumping; default is yes to be
1178  * sure (missing info is worse than too much; etc).
1179  * Personally I'd include everything, and use the coredump limit...
1180  *
1181  * I think we should skip something. But I am not sure how. H.J.
1182  */
1183 static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1184 {
1185         int dump_ok;
1186 
1187         /* Do not dump I/O mapped devices or special mappings */
1188         if (vma->vm_flags & VM_IO) {
1189                 kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1190                 return 0;
1191         }
1192 
1193         /* If we may not read the contents, don't allow us to dump
1194          * them either. "dump_write()" can't handle it anyway.
1195          */
1196         if (!(vma->vm_flags & VM_READ)) {
1197                 kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1198                 return 0;
1199         }
1200 
1201         /* support for DAX */
1202         if (vma_is_dax(vma)) {
1203                 if (vma->vm_flags & VM_SHARED) {
1204                         dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
1205                         kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
1206                                vma->vm_flags, dump_ok ? "yes" : "no");
1207                 } else {
1208                         dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
1209                         kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
1210                                vma->vm_flags, dump_ok ? "yes" : "no");
1211                 }
1212                 return dump_ok;
1213         }
1214 
1215         /* By default, dump shared memory if mapped from an anonymous file. */
1216         if (vma->vm_flags & VM_SHARED) {
1217                 if (file_inode(vma->vm_file)->i_nlink == 0) {
1218                         dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
1219                         kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1220                                vma->vm_flags, dump_ok ? "yes" : "no");
1221                         return dump_ok;
1222                 }
1223 
1224                 dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
1225                 kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1226                        vma->vm_flags, dump_ok ? "yes" : "no");
1227                 return dump_ok;
1228         }
1229 
1230 #ifdef CONFIG_MMU
1231         /* By default, if it hasn't been written to, don't write it out */
1232         if (!vma->anon_vma) {
1233                 dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1234                 kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1235                        vma->vm_flags, dump_ok ? "yes" : "no");
1236                 return dump_ok;
1237         }
1238 #endif
1239 
1240         dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1241         kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1242                dump_ok ? "yes" : "no");
1243         return dump_ok;
1244 }
1245 
1246 /* An ELF note in memory */
1247 struct memelfnote
1248 {
1249         const char *name;
1250         int type;
1251         unsigned int datasz;
1252         void *data;
1253 };
1254 
1255 static int notesize(struct memelfnote *en)
1256 {
1257         int sz;
1258 
1259         sz = sizeof(struct elf_note);
1260         sz += roundup(strlen(en->name) + 1, 4);
1261         sz += roundup(en->datasz, 4);
1262 
1263         return sz;
1264 }
1265 
1266 /* #define DEBUG */
1267 
1268 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1269 {
1270         struct elf_note en;
1271         en.n_namesz = strlen(men->name) + 1;
1272         en.n_descsz = men->datasz;
1273         en.n_type = men->type;
1274 
1275         return dump_emit(cprm, &en, sizeof(en)) &&
1276                 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1277                 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1278 }
1279 
1280 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1281 {
1282         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1283         elf->e_ident[EI_CLASS] = ELF_CLASS;
1284         elf->e_ident[EI_DATA] = ELF_DATA;
1285         elf->e_ident[EI_VERSION] = EV_CURRENT;
1286         elf->e_ident[EI_OSABI] = ELF_OSABI;
1287         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1288 
1289         elf->e_type = ET_CORE;
1290         elf->e_machine = ELF_ARCH;
1291         elf->e_version = EV_CURRENT;
1292         elf->e_entry = 0;
1293         elf->e_phoff = sizeof(struct elfhdr);
1294         elf->e_shoff = 0;
1295         elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1296         elf->e_ehsize = sizeof(struct elfhdr);
1297         elf->e_phentsize = sizeof(struct elf_phdr);
1298         elf->e_phnum = segs;
1299         elf->e_shentsize = 0;
1300         elf->e_shnum = 0;
1301         elf->e_shstrndx = 0;
1302         return;
1303 }
1304 
1305 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1306 {
1307         phdr->p_type = PT_NOTE;
1308         phdr->p_offset = offset;
1309         phdr->p_vaddr = 0;
1310         phdr->p_paddr = 0;
1311         phdr->p_filesz = sz;
1312         phdr->p_memsz = 0;
1313         phdr->p_flags = 0;
1314         phdr->p_align = 0;
1315         return;
1316 }
1317 
1318 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1319                 unsigned int sz, void *data)
1320 {
1321         note->name = name;
1322         note->type = type;
1323         note->datasz = sz;
1324         note->data = data;
1325         return;
1326 }
1327 
1328 /*
1329  * fill up all the fields in prstatus from the given task struct, except
1330  * registers which need to be filled up separately.
1331  */
1332 static void fill_prstatus(struct elf_prstatus *prstatus,
1333                           struct task_struct *p, long signr)
1334 {
1335         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1336         prstatus->pr_sigpend = p->pending.signal.sig[0];
1337         prstatus->pr_sighold = p->blocked.sig[0];
1338         rcu_read_lock();
1339         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1340         rcu_read_unlock();
1341         prstatus->pr_pid = task_pid_vnr(p);
1342         prstatus->pr_pgrp = task_pgrp_vnr(p);
1343         prstatus->pr_sid = task_session_vnr(p);
1344         if (thread_group_leader(p)) {
1345                 struct task_cputime cputime;
1346 
1347                 /*
1348                  * This is the record for the group leader.  It shows the
1349                  * group-wide total, not its individual thread total.
1350                  */
1351                 thread_group_cputime(p, &cputime);
1352                 cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1353                 cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1354         } else {
1355                 cputime_t utime, stime;
1356 
1357                 task_cputime(p, &utime, &stime);
1358                 cputime_to_timeval(utime, &prstatus->pr_utime);
1359                 cputime_to_timeval(stime, &prstatus->pr_stime);
1360         }
1361         cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1362         cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1363 
1364         prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1365         prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1366 }
1367 
1368 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1369                        struct mm_struct *mm)
1370 {
1371         const struct cred *cred;
1372         unsigned int i, len;
1373 
1374         /* first copy the parameters from user space */
1375         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1376 
1377         len = mm->arg_end - mm->arg_start;
1378         if (len >= ELF_PRARGSZ)
1379                 len = ELF_PRARGSZ - 1;
1380         if (copy_from_user(&psinfo->pr_psargs,
1381                            (const char __user *) mm->arg_start, len))
1382                 return -EFAULT;
1383         for (i = 0; i < len; i++)
1384                 if (psinfo->pr_psargs[i] == 0)
1385                         psinfo->pr_psargs[i] = ' ';
1386         psinfo->pr_psargs[len] = 0;
1387 
1388         rcu_read_lock();
1389         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1390         rcu_read_unlock();
1391         psinfo->pr_pid = task_pid_vnr(p);
1392         psinfo->pr_pgrp = task_pgrp_vnr(p);
1393         psinfo->pr_sid = task_session_vnr(p);
1394 
1395         i = p->state ? ffz(~p->state) + 1 : 0;
1396         psinfo->pr_state = i;
1397         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1398         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1399         psinfo->pr_nice = task_nice(p);
1400         psinfo->pr_flag = p->flags;
1401         rcu_read_lock();
1402         cred = __task_cred(p);
1403         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1404         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1405         rcu_read_unlock();
1406         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1407 
1408         return 0;
1409 }
1410 
1411 /* Here is the structure in which status of each thread is captured. */
1412 struct elf_thread_status
1413 {
1414         struct list_head list;
1415         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1416         elf_fpregset_t fpu;             /* NT_PRFPREG */
1417         struct task_struct *thread;
1418 #ifdef ELF_CORE_COPY_XFPREGS
1419         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1420 #endif
1421         struct memelfnote notes[3];
1422         int num_notes;
1423 };
1424 
1425 /*
1426  * In order to add the specific thread information for the elf file format,
1427  * we need to keep a linked list of every thread's pr_status and then create
1428  * a single section for them in the final core file.
1429  */
1430 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1431 {
1432         struct task_struct *p = t->thread;
1433         int sz = 0;
1434 
1435         t->num_notes = 0;
1436 
1437         fill_prstatus(&t->prstatus, p, signr);
1438         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1439 
1440         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1441                   &t->prstatus);
1442         t->num_notes++;
1443         sz += notesize(&t->notes[0]);
1444 
1445         t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1446         if (t->prstatus.pr_fpvalid) {
1447                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1448                           &t->fpu);
1449                 t->num_notes++;
1450                 sz += notesize(&t->notes[1]);
1451         }
1452 
1453 #ifdef ELF_CORE_COPY_XFPREGS
1454         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1455                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1456                           sizeof(t->xfpu), &t->xfpu);
1457                 t->num_notes++;
1458                 sz += notesize(&t->notes[2]);
1459         }
1460 #endif
1461         return sz;
1462 }
1463 
1464 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1465                              elf_addr_t e_shoff, int segs)
1466 {
1467         elf->e_shoff = e_shoff;
1468         elf->e_shentsize = sizeof(*shdr4extnum);
1469         elf->e_shnum = 1;
1470         elf->e_shstrndx = SHN_UNDEF;
1471 
1472         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1473 
1474         shdr4extnum->sh_type = SHT_NULL;
1475         shdr4extnum->sh_size = elf->e_shnum;
1476         shdr4extnum->sh_link = elf->e_shstrndx;
1477         shdr4extnum->sh_info = segs;
1478 }
1479 
1480 /*
1481  * dump the segments for an MMU process
1482  */
1483 static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
1484 {
1485         struct vm_area_struct *vma;
1486 
1487         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1488                 unsigned long addr;
1489 
1490                 if (!maydump(vma, cprm->mm_flags))
1491                         continue;
1492 
1493 #ifdef CONFIG_MMU
1494                 for (addr = vma->vm_start; addr < vma->vm_end;
1495                                                         addr += PAGE_SIZE) {
1496                         bool res;
1497                         struct page *page = get_dump_page(addr);
1498                         if (page) {
1499                                 void *kaddr = kmap(page);
1500                                 res = dump_emit(cprm, kaddr, PAGE_SIZE);
1501                                 kunmap(page);
1502                                 put_page(page);
1503                         } else {
1504                                 res = dump_skip(cprm, PAGE_SIZE);
1505                         }
1506                         if (!res)
1507                                 return false;
1508                 }
1509 #else
1510                 if (!dump_emit(cprm, (void *) vma->vm_start,
1511                                 vma->vm_end - vma->vm_start))
1512                         return false;
1513 #endif
1514         }
1515         return true;
1516 }
1517 
1518 static size_t elf_core_vma_data_size(unsigned long mm_flags)
1519 {
1520         struct vm_area_struct *vma;
1521         size_t size = 0;
1522 
1523         for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1524                 if (maydump(vma, mm_flags))
1525                         size += vma->vm_end - vma->vm_start;
1526         return size;
1527 }
1528 
1529 /*
1530  * Actual dumper
1531  *
1532  * This is a two-pass process; first we find the offsets of the bits,
1533  * and then they are actually written out.  If we run out of core limit
1534  * we just truncate.
1535  */
1536 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1537 {
1538 #define NUM_NOTES       6
1539         int has_dumped = 0;
1540         mm_segment_t fs;
1541         int segs;
1542         int i;
1543         struct vm_area_struct *vma;
1544         struct elfhdr *elf = NULL;
1545         loff_t offset = 0, dataoff;
1546         int numnote;
1547         struct memelfnote *notes = NULL;
1548         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
1549         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1550         LIST_HEAD(thread_list);
1551         struct list_head *t;
1552         elf_fpregset_t *fpu = NULL;
1553 #ifdef ELF_CORE_COPY_XFPREGS
1554         elf_fpxregset_t *xfpu = NULL;
1555 #endif
1556         int thread_status_size = 0;
1557         elf_addr_t *auxv;
1558         struct elf_phdr *phdr4note = NULL;
1559         struct elf_shdr *shdr4extnum = NULL;
1560         Elf_Half e_phnum;
1561         elf_addr_t e_shoff;
1562         struct core_thread *ct;
1563         struct elf_thread_status *tmp;
1564 
1565         /*
1566          * We no longer stop all VM operations.
1567          *
1568          * This is because those proceses that could possibly change map_count
1569          * or the mmap / vma pages are now blocked in do_exit on current
1570          * finishing this core dump.
1571          *
1572          * Only ptrace can touch these memory addresses, but it doesn't change
1573          * the map_count or the pages allocated. So no possibility of crashing
1574          * exists while dumping the mm->vm_next areas to the core file.
1575          */
1576 
1577         /* alloc memory for large data structures: too large to be on stack */
1578         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1579         if (!elf)
1580                 goto cleanup;
1581         prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1582         if (!prstatus)
1583                 goto cleanup;
1584         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1585         if (!psinfo)
1586                 goto cleanup;
1587         notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
1588         if (!notes)
1589                 goto cleanup;
1590         fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1591         if (!fpu)
1592                 goto cleanup;
1593 #ifdef ELF_CORE_COPY_XFPREGS
1594         xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1595         if (!xfpu)
1596                 goto cleanup;
1597 #endif
1598 
1599         for (ct = current->mm->core_state->dumper.next;
1600                                         ct; ct = ct->next) {
1601                 tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1602                 if (!tmp)
1603                         goto cleanup;
1604 
1605                 tmp->thread = ct->task;
1606                 list_add(&tmp->list, &thread_list);
1607         }
1608 
1609         list_for_each(t, &thread_list) {
1610                 struct elf_thread_status *tmp;
1611                 int sz;
1612 
1613                 tmp = list_entry(t, struct elf_thread_status, list);
1614                 sz = elf_dump_thread_status(cprm->siginfo->si_signo, tmp);
1615                 thread_status_size += sz;
1616         }
1617 
1618         /* now collect the dump for the current */
1619         fill_prstatus(prstatus, current, cprm->siginfo->si_signo);
1620         elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1621 
1622         segs = current->mm->map_count;
1623         segs += elf_core_extra_phdrs();
1624 
1625         /* for notes section */
1626         segs++;
1627 
1628         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1629          * this, kernel supports extended numbering. Have a look at
1630          * include/linux/elf.h for further information. */
1631         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1632 
1633         /* Set up header */
1634         fill_elf_fdpic_header(elf, e_phnum);
1635 
1636         has_dumped = 1;
1637         /*
1638          * Set up the notes in similar form to SVR4 core dumps made
1639          * with info from their /proc.
1640          */
1641 
1642         fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1643         fill_psinfo(psinfo, current->group_leader, current->mm);
1644         fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1645 
1646         numnote = 2;
1647 
1648         auxv = (elf_addr_t *) current->mm->saved_auxv;
1649 
1650         i = 0;
1651         do
1652                 i += 2;
1653         while (auxv[i - 2] != AT_NULL);
1654         fill_note(&notes[numnote++], "CORE", NT_AUXV,
1655                   i * sizeof(elf_addr_t), auxv);
1656 
1657         /* Try to dump the FPU. */
1658         if ((prstatus->pr_fpvalid =
1659              elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1660                 fill_note(notes + numnote++,
1661                           "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1662 #ifdef ELF_CORE_COPY_XFPREGS
1663         if (elf_core_copy_task_xfpregs(current, xfpu))
1664                 fill_note(notes + numnote++,
1665                           "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1666 #endif
1667 
1668         fs = get_fs();
1669         set_fs(KERNEL_DS);
1670 
1671         offset += sizeof(*elf);                         /* Elf header */
1672         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1673 
1674         /* Write notes phdr entry */
1675         {
1676                 int sz = 0;
1677 
1678                 for (i = 0; i < numnote; i++)
1679                         sz += notesize(notes + i);
1680 
1681                 sz += thread_status_size;
1682 
1683                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1684                 if (!phdr4note)
1685                         goto end_coredump;
1686 
1687                 fill_elf_note_phdr(phdr4note, sz, offset);
1688                 offset += sz;
1689         }
1690 
1691         /* Page-align dumped data */
1692         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1693 
1694         offset += elf_core_vma_data_size(cprm->mm_flags);
1695         offset += elf_core_extra_data_size();
1696         e_shoff = offset;
1697 
1698         if (e_phnum == PN_XNUM) {
1699                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1700                 if (!shdr4extnum)
1701                         goto end_coredump;
1702                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1703         }
1704 
1705         offset = dataoff;
1706 
1707         if (!dump_emit(cprm, elf, sizeof(*elf)))
1708                 goto end_coredump;
1709 
1710         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1711                 goto end_coredump;
1712 
1713         /* write program headers for segments dump */
1714         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1715                 struct elf_phdr phdr;
1716                 size_t sz;
1717 
1718                 sz = vma->vm_end - vma->vm_start;
1719 
1720                 phdr.p_type = PT_LOAD;
1721                 phdr.p_offset = offset;
1722                 phdr.p_vaddr = vma->vm_start;
1723                 phdr.p_paddr = 0;
1724                 phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1725                 phdr.p_memsz = sz;
1726                 offset += phdr.p_filesz;
1727                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1728                 if (vma->vm_flags & VM_WRITE)
1729                         phdr.p_flags |= PF_W;
1730                 if (vma->vm_flags & VM_EXEC)
1731                         phdr.p_flags |= PF_X;
1732                 phdr.p_align = ELF_EXEC_PAGESIZE;
1733 
1734                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1735                         goto end_coredump;
1736         }
1737 
1738         if (!elf_core_write_extra_phdrs(cprm, offset))
1739                 goto end_coredump;
1740 
1741         /* write out the notes section */
1742         for (i = 0; i < numnote; i++)
1743                 if (!writenote(notes + i, cprm))
1744                         goto end_coredump;
1745 
1746         /* write out the thread status notes section */
1747         list_for_each(t, &thread_list) {
1748                 struct elf_thread_status *tmp =
1749                                 list_entry(t, struct elf_thread_status, list);
1750 
1751                 for (i = 0; i < tmp->num_notes; i++)
1752                         if (!writenote(&tmp->notes[i], cprm))
1753                                 goto end_coredump;
1754         }
1755 
1756         if (!dump_skip(cprm, dataoff - cprm->pos))
1757                 goto end_coredump;
1758 
1759         if (!elf_fdpic_dump_segments(cprm))
1760                 goto end_coredump;
1761 
1762         if (!elf_core_write_extra_data(cprm))
1763                 goto end_coredump;
1764 
1765         if (e_phnum == PN_XNUM) {
1766                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1767                         goto end_coredump;
1768         }
1769 
1770         if (cprm->file->f_pos != offset) {
1771                 /* Sanity check */
1772                 printk(KERN_WARNING
1773                        "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1774                        cprm->file->f_pos, offset);
1775         }
1776 
1777 end_coredump:
1778         set_fs(fs);
1779 
1780 cleanup:
1781         while (!list_empty(&thread_list)) {
1782                 struct list_head *tmp = thread_list.next;
1783                 list_del(tmp);
1784                 kfree(list_entry(tmp, struct elf_thread_status, list));
1785         }
1786         kfree(phdr4note);
1787         kfree(elf);
1788         kfree(prstatus);
1789         kfree(psinfo);
1790         kfree(notes);
1791         kfree(fpu);
1792         kfree(shdr4extnum);
1793 #ifdef ELF_CORE_COPY_XFPREGS
1794         kfree(xfpu);
1795 #endif
1796         return has_dumped;
1797 #undef NUM_NOTES
1798 }
1799 
1800 #endif          /* CONFIG_ELF_CORE */
1801 

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