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Linux/fs/binfmt_elf_fdpic.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
  3  *
  4  * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
  5  * Written by David Howells (dhowells@redhat.com)
  6  * Derived from binfmt_elf.c
  7  */
  8 
  9 #include <linux/module.h>
 10 
 11 #include <linux/fs.h>
 12 #include <linux/stat.h>
 13 #include <linux/sched.h>
 14 #include <linux/sched/coredump.h>
 15 #include <linux/sched/task_stack.h>
 16 #include <linux/sched/cputime.h>
 17 #include <linux/mm.h>
 18 #include <linux/mman.h>
 19 #include <linux/errno.h>
 20 #include <linux/signal.h>
 21 #include <linux/binfmts.h>
 22 #include <linux/string.h>
 23 #include <linux/file.h>
 24 #include <linux/fcntl.h>
 25 #include <linux/slab.h>
 26 #include <linux/pagemap.h>
 27 #include <linux/security.h>
 28 #include <linux/highmem.h>
 29 #include <linux/highuid.h>
 30 #include <linux/personality.h>
 31 #include <linux/ptrace.h>
 32 #include <linux/init.h>
 33 #include <linux/elf.h>
 34 #include <linux/elf-fdpic.h>
 35 #include <linux/elfcore.h>
 36 #include <linux/coredump.h>
 37 #include <linux/dax.h>
 38 #include <linux/regset.h>
 39 
 40 #include <linux/uaccess.h>
 41 #include <asm/param.h>
 42 
 43 typedef char *elf_caddr_t;
 44 
 45 #if 0
 46 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
 47 #else
 48 #define kdebug(fmt, ...) do {} while(0)
 49 #endif
 50 
 51 #if 0
 52 #define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
 53 #else
 54 #define kdcore(fmt, ...) do {} while(0)
 55 #endif
 56 
 57 MODULE_LICENSE("GPL");
 58 
 59 static int load_elf_fdpic_binary(struct linux_binprm *);
 60 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
 61 static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
 62                               struct mm_struct *, const char *);
 63 
 64 static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
 65                                    struct elf_fdpic_params *,
 66                                    struct elf_fdpic_params *);
 67 
 68 #ifndef CONFIG_MMU
 69 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
 70                                                    struct file *,
 71                                                    struct mm_struct *);
 72 #endif
 73 
 74 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
 75                                              struct file *, struct mm_struct *);
 76 
 77 #ifdef CONFIG_ELF_CORE
 78 static int elf_fdpic_core_dump(struct coredump_params *cprm);
 79 #endif
 80 
 81 static struct linux_binfmt elf_fdpic_format = {
 82         .module         = THIS_MODULE,
 83         .load_binary    = load_elf_fdpic_binary,
 84 #ifdef CONFIG_ELF_CORE
 85         .core_dump      = elf_fdpic_core_dump,
 86 #endif
 87         .min_coredump   = ELF_EXEC_PAGESIZE,
 88 };
 89 
 90 static int __init init_elf_fdpic_binfmt(void)
 91 {
 92         register_binfmt(&elf_fdpic_format);
 93         return 0;
 94 }
 95 
 96 static void __exit exit_elf_fdpic_binfmt(void)
 97 {
 98         unregister_binfmt(&elf_fdpic_format);
 99 }
100 
101 core_initcall(init_elf_fdpic_binfmt);
102 module_exit(exit_elf_fdpic_binfmt);
103 
104 static int is_elf(struct elfhdr *hdr, struct file *file)
105 {
106         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
107                 return 0;
108         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
109                 return 0;
110         if (!elf_check_arch(hdr))
111                 return 0;
112         if (!file->f_op->mmap)
113                 return 0;
114         return 1;
115 }
116 
117 #ifndef elf_check_fdpic
118 #define elf_check_fdpic(x) 0
119 #endif
120 
121 #ifndef elf_check_const_displacement
122 #define elf_check_const_displacement(x) 0
123 #endif
124 
125 static int is_constdisp(struct elfhdr *hdr)
126 {
127         if (!elf_check_fdpic(hdr))
128                 return 1;
129         if (elf_check_const_displacement(hdr))
130                 return 1;
131         return 0;
132 }
133 
134 /*****************************************************************************/
135 /*
136  * read the program headers table into memory
137  */
138 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
139                                  struct file *file)
140 {
141         struct elf32_phdr *phdr;
142         unsigned long size;
143         int retval, loop;
144         loff_t pos = params->hdr.e_phoff;
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->phdrs, size, &pos);
157         if (unlikely(retval != size))
158                 return retval < 0 ? retval : -ENOEXEC;
159 
160         /* determine stack size for this binary */
161         phdr = params->phdrs;
162         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
163                 if (phdr->p_type != PT_GNU_STACK)
164                         continue;
165 
166                 if (phdr->p_flags & PF_X)
167                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
168                 else
169                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
170 
171                 params->stack_size = phdr->p_memsz;
172                 break;
173         }
174 
175         return 0;
176 }
177 
178 /*****************************************************************************/
179 /*
180  * load an fdpic binary into various bits of memory
181  */
182 static int load_elf_fdpic_binary(struct linux_binprm *bprm)
183 {
184         struct elf_fdpic_params exec_params, interp_params;
185         struct pt_regs *regs = current_pt_regs();
186         struct elf_phdr *phdr;
187         unsigned long stack_size, entryaddr;
188 #ifdef ELF_FDPIC_PLAT_INIT
189         unsigned long dynaddr;
190 #endif
191 #ifndef CONFIG_MMU
192         unsigned long stack_prot;
193 #endif
194         struct file *interpreter = NULL; /* to shut gcc up */
195         char *interpreter_name = NULL;
196         int executable_stack;
197         int retval, i;
198         loff_t pos;
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                         pos = phdr->p_offset;
247                         retval = kernel_read(bprm->file, interpreter_name,
248                                              phdr->p_filesz, &pos);
249                         if (unlikely(retval != phdr->p_filesz)) {
250                                 if (retval >= 0)
251                                         retval = -ENOEXEC;
252                                 goto error;
253                         }
254 
255                         retval = -ENOENT;
256                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
257                                 goto error;
258 
259                         kdebug("Using ELF interpreter %s", interpreter_name);
260 
261                         /* replace the program with the interpreter */
262                         interpreter = open_exec(interpreter_name);
263                         retval = PTR_ERR(interpreter);
264                         if (IS_ERR(interpreter)) {
265                                 interpreter = NULL;
266                                 goto error;
267                         }
268 
269                         /*
270                          * If the binary is not readable then enforce
271                          * mm->dumpable = 0 regardless of the interpreter's
272                          * permissions.
273                          */
274                         would_dump(bprm, interpreter);
275 
276                         pos = 0;
277                         retval = kernel_read(interpreter, bprm->buf,
278                                         BINPRM_BUF_SIZE, &pos);
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 = begin_new_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 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
378         retval = arch_setup_additional_pages(bprm, !!interpreter_name);
379         if (retval < 0)
380                 goto error;
381 #endif
382 #endif
383 
384         /* load the executable and interpreter into memory */
385         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
386                                     "executable");
387         if (retval < 0)
388                 goto error;
389 
390         if (interpreter_name) {
391                 retval = elf_fdpic_map_file(&interp_params, interpreter,
392                                             current->mm, "interpreter");
393                 if (retval < 0) {
394                         printk(KERN_ERR "Unable to load interpreter\n");
395                         goto error;
396                 }
397 
398                 allow_write_access(interpreter);
399                 fput(interpreter);
400                 interpreter = NULL;
401         }
402 
403 #ifdef CONFIG_MMU
404         if (!current->mm->start_brk)
405                 current->mm->start_brk = current->mm->end_data;
406 
407         current->mm->brk = current->mm->start_brk =
408                 PAGE_ALIGN(current->mm->start_brk);
409 
410 #else
411         /* create a stack area and zero-size brk area */
412         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
413         if (stack_size < PAGE_SIZE * 2)
414                 stack_size = PAGE_SIZE * 2;
415 
416         stack_prot = PROT_READ | PROT_WRITE;
417         if (executable_stack == EXSTACK_ENABLE_X ||
418             (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
419                 stack_prot |= PROT_EXEC;
420 
421         current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
422                                          MAP_PRIVATE | MAP_ANONYMOUS |
423                                          MAP_UNINITIALIZED | MAP_GROWSDOWN,
424                                          0);
425 
426         if (IS_ERR_VALUE(current->mm->start_brk)) {
427                 retval = current->mm->start_brk;
428                 current->mm->start_brk = 0;
429                 goto error;
430         }
431 
432         current->mm->brk = current->mm->start_brk;
433         current->mm->context.end_brk = current->mm->start_brk;
434         current->mm->start_stack = current->mm->start_brk + stack_size;
435 #endif
436 
437         if (create_elf_fdpic_tables(bprm, current->mm,
438                                     &exec_params, &interp_params) < 0)
439                 goto error;
440 
441         kdebug("- start_code  %lx", current->mm->start_code);
442         kdebug("- end_code    %lx", current->mm->end_code);
443         kdebug("- start_data  %lx", current->mm->start_data);
444         kdebug("- end_data    %lx", current->mm->end_data);
445         kdebug("- start_brk   %lx", current->mm->start_brk);
446         kdebug("- brk         %lx", current->mm->brk);
447         kdebug("- start_stack %lx", current->mm->start_stack);
448 
449 #ifdef ELF_FDPIC_PLAT_INIT
450         /*
451          * The ABI may specify that certain registers be set up in special
452          * ways (on i386 %edx is the address of a DT_FINI function, for
453          * example.  This macro performs whatever initialization to
454          * the regs structure is required.
455          */
456         dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
457         ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
458                             dynaddr);
459 #endif
460 
461         finalize_exec(bprm);
462         /* everything is now ready... get the userspace context ready to roll */
463         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
464         start_thread(regs, entryaddr, current->mm->start_stack);
465 
466         retval = 0;
467 
468 error:
469         if (interpreter) {
470                 allow_write_access(interpreter);
471                 fput(interpreter);
472         }
473         kfree(interpreter_name);
474         kfree(exec_params.phdrs);
475         kfree(exec_params.loadmap);
476         kfree(interp_params.phdrs);
477         kfree(interp_params.loadmap);
478         return retval;
479 }
480 
481 /*****************************************************************************/
482 
483 #ifndef ELF_BASE_PLATFORM
484 /*
485  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
486  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
487  * will be copied to the user stack in the same manner as AT_PLATFORM.
488  */
489 #define ELF_BASE_PLATFORM NULL
490 #endif
491 
492 /*
493  * present useful information to the program by shovelling it onto the new
494  * process's stack
495  */
496 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
497                                    struct mm_struct *mm,
498                                    struct elf_fdpic_params *exec_params,
499                                    struct elf_fdpic_params *interp_params)
500 {
501         const struct cred *cred = current_cred();
502         unsigned long sp, csp, nitems;
503         elf_caddr_t __user *argv, *envp;
504         size_t platform_len = 0, len;
505         char *k_platform, *k_base_platform;
506         char __user *u_platform, *u_base_platform, *p;
507         int loop;
508         int nr; /* reset for each csp adjustment */
509         unsigned long flags = 0;
510 
511 #ifdef CONFIG_MMU
512         /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
513          * by the processes running on the same package. One thing we can do is
514          * to shuffle the initial stack for them, so we give the architecture
515          * an opportunity to do so here.
516          */
517         sp = arch_align_stack(bprm->p);
518 #else
519         sp = mm->start_stack;
520 
521         /* stack the program arguments and environment */
522         if (transfer_args_to_stack(bprm, &sp) < 0)
523                 return -EFAULT;
524         sp &= ~15;
525 #endif
526 
527         /*
528          * If this architecture has a platform capability string, copy it
529          * to userspace.  In some cases (Sparc), this info is impossible
530          * for userspace to get any other way, in others (i386) it is
531          * merely difficult.
532          */
533         k_platform = ELF_PLATFORM;
534         u_platform = NULL;
535 
536         if (k_platform) {
537                 platform_len = strlen(k_platform) + 1;
538                 sp -= platform_len;
539                 u_platform = (char __user *) sp;
540                 if (copy_to_user(u_platform, k_platform, platform_len) != 0)
541                         return -EFAULT;
542         }
543 
544         /*
545          * If this architecture has a "base" platform capability
546          * string, copy it to userspace.
547          */
548         k_base_platform = ELF_BASE_PLATFORM;
549         u_base_platform = NULL;
550 
551         if (k_base_platform) {
552                 platform_len = strlen(k_base_platform) + 1;
553                 sp -= platform_len;
554                 u_base_platform = (char __user *) sp;
555                 if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
556                         return -EFAULT;
557         }
558 
559         sp &= ~7UL;
560 
561         /* stack the load map(s) */
562         len = sizeof(struct elf32_fdpic_loadmap);
563         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
564         sp = (sp - len) & ~7UL;
565         exec_params->map_addr = sp;
566 
567         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
568                 return -EFAULT;
569 
570         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
571 
572         if (interp_params->loadmap) {
573                 len = sizeof(struct elf32_fdpic_loadmap);
574                 len += sizeof(struct elf32_fdpic_loadseg) *
575                         interp_params->loadmap->nsegs;
576                 sp = (sp - len) & ~7UL;
577                 interp_params->map_addr = sp;
578 
579                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
580                                  len) != 0)
581                         return -EFAULT;
582 
583                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
584         }
585 
586         /* force 16 byte _final_ alignment here for generality */
587 #define DLINFO_ITEMS 15
588 
589         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
590                 (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
591 
592         if (bprm->have_execfd)
593                 nitems++;
594 
595         csp = sp;
596         sp -= nitems * 2 * sizeof(unsigned long);
597         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
598         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
599         sp -= 1 * sizeof(unsigned long);                /* argc */
600 
601         csp -= sp & 15UL;
602         sp -= sp & 15UL;
603 
604         /* put the ELF interpreter info on the stack */
605 #define NEW_AUX_ENT(id, val)                                            \
606         do {                                                            \
607                 struct { unsigned long _id, _val; } __user *ent, v;     \
608                                                                         \
609                 ent = (void __user *) csp;                              \
610                 v._id = (id);                                           \
611                 v._val = (val);                                         \
612                 if (copy_to_user(ent + nr, &v, sizeof(v)))              \
613                         return -EFAULT;                                 \
614                 nr++;                                                   \
615         } while (0)
616 
617         nr = 0;
618         csp -= 2 * sizeof(unsigned long);
619         NEW_AUX_ENT(AT_NULL, 0);
620         if (k_platform) {
621                 nr = 0;
622                 csp -= 2 * sizeof(unsigned long);
623                 NEW_AUX_ENT(AT_PLATFORM,
624                             (elf_addr_t) (unsigned long) u_platform);
625         }
626 
627         if (k_base_platform) {
628                 nr = 0;
629                 csp -= 2 * sizeof(unsigned long);
630                 NEW_AUX_ENT(AT_BASE_PLATFORM,
631                             (elf_addr_t) (unsigned long) u_base_platform);
632         }
633 
634         if (bprm->have_execfd) {
635                 nr = 0;
636                 csp -= 2 * sizeof(unsigned long);
637                 NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
638         }
639 
640         nr = 0;
641         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
642         NEW_AUX_ENT(AT_HWCAP,   ELF_HWCAP);
643 #ifdef ELF_HWCAP2
644         NEW_AUX_ENT(AT_HWCAP2,  ELF_HWCAP2);
645 #endif
646         NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
647         NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
648         NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
649         NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
650         NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
651         NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
652         if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
653                 flags |= AT_FLAGS_PRESERVE_ARGV0;
654         NEW_AUX_ENT(AT_FLAGS,   flags);
655         NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
656         NEW_AUX_ENT(AT_UID,     (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
657         NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
658         NEW_AUX_ENT(AT_GID,     (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
659         NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
660         NEW_AUX_ENT(AT_SECURE,  bprm->secureexec);
661         NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
662 
663 #ifdef ARCH_DLINFO
664         nr = 0;
665         csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
666 
667         /* ARCH_DLINFO must come last so platform specific code can enforce
668          * special alignment requirements on the AUXV if necessary (eg. PPC).
669          */
670         ARCH_DLINFO;
671 #endif
672 #undef NEW_AUX_ENT
673 
674         /* allocate room for argv[] and envv[] */
675         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
676         envp = (elf_caddr_t __user *) csp;
677         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
678         argv = (elf_caddr_t __user *) csp;
679 
680         /* stack argc */
681         csp -= sizeof(unsigned long);
682         if (put_user(bprm->argc, (unsigned long __user *) csp))
683                 return -EFAULT;
684 
685         BUG_ON(csp != sp);
686 
687         /* fill in the argv[] array */
688 #ifdef CONFIG_MMU
689         current->mm->arg_start = bprm->p;
690 #else
691         current->mm->arg_start = current->mm->start_stack -
692                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
693 #endif
694 
695         p = (char __user *) current->mm->arg_start;
696         for (loop = bprm->argc; loop > 0; loop--) {
697                 if (put_user((elf_caddr_t) p, argv++))
698                         return -EFAULT;
699                 len = strnlen_user(p, MAX_ARG_STRLEN);
700                 if (!len || len > MAX_ARG_STRLEN)
701                         return -EINVAL;
702                 p += len;
703         }
704         if (put_user(NULL, argv))
705                 return -EFAULT;
706         current->mm->arg_end = (unsigned long) p;
707 
708         /* fill in the envv[] array */
709         current->mm->env_start = (unsigned long) p;
710         for (loop = bprm->envc; loop > 0; loop--) {
711                 if (put_user((elf_caddr_t)(unsigned long) p, envp++))
712                         return -EFAULT;
713                 len = strnlen_user(p, MAX_ARG_STRLEN);
714                 if (!len || len > MAX_ARG_STRLEN)
715                         return -EINVAL;
716                 p += len;
717         }
718         if (put_user(NULL, envp))
719                 return -EFAULT;
720         current->mm->env_end = (unsigned long) p;
721 
722         mm->start_stack = (unsigned long) sp;
723         return 0;
724 }
725 
726 /*****************************************************************************/
727 /*
728  * load the appropriate binary image (executable or interpreter) into memory
729  * - we assume no MMU is available
730  * - if no other PIC bits are set in params->hdr->e_flags
731  *   - we assume that the LOADable segments in the binary are independently relocatable
732  *   - we assume R/O executable segments are shareable
733  * - else
734  *   - we assume the loadable parts of the image to require fixed displacement
735  *   - the image is not shareable
736  */
737 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
738                               struct file *file,
739                               struct mm_struct *mm,
740                               const char *what)
741 {
742         struct elf32_fdpic_loadmap *loadmap;
743 #ifdef CONFIG_MMU
744         struct elf32_fdpic_loadseg *mseg;
745 #endif
746         struct elf32_fdpic_loadseg *seg;
747         struct elf32_phdr *phdr;
748         unsigned long load_addr, stop;
749         unsigned nloads, tmp;
750         size_t size;
751         int loop, ret;
752 
753         /* allocate a load map table */
754         nloads = 0;
755         for (loop = 0; loop < params->hdr.e_phnum; loop++)
756                 if (params->phdrs[loop].p_type == PT_LOAD)
757                         nloads++;
758 
759         if (nloads == 0)
760                 return -ELIBBAD;
761 
762         size = sizeof(*loadmap) + nloads * sizeof(*seg);
763         loadmap = kzalloc(size, GFP_KERNEL);
764         if (!loadmap)
765                 return -ENOMEM;
766 
767         params->loadmap = loadmap;
768 
769         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
770         loadmap->nsegs = nloads;
771 
772         load_addr = params->load_addr;
773         seg = loadmap->segs;
774 
775         /* map the requested LOADs into the memory space */
776         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
777         case ELF_FDPIC_FLAG_CONSTDISP:
778         case ELF_FDPIC_FLAG_CONTIGUOUS:
779 #ifndef CONFIG_MMU
780                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
781                 if (ret < 0)
782                         return ret;
783                 break;
784 #endif
785         default:
786                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
787                 if (ret < 0)
788                         return ret;
789                 break;
790         }
791 
792         /* map the entry point */
793         if (params->hdr.e_entry) {
794                 seg = loadmap->segs;
795                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
796                         if (params->hdr.e_entry >= seg->p_vaddr &&
797                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
798                                 params->entry_addr =
799                                         (params->hdr.e_entry - seg->p_vaddr) +
800                                         seg->addr;
801                                 break;
802                         }
803                 }
804         }
805 
806         /* determine where the program header table has wound up if mapped */
807         stop = params->hdr.e_phoff;
808         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
809         phdr = params->phdrs;
810 
811         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
812                 if (phdr->p_type != PT_LOAD)
813                         continue;
814 
815                 if (phdr->p_offset > params->hdr.e_phoff ||
816                     phdr->p_offset + phdr->p_filesz < stop)
817                         continue;
818 
819                 seg = loadmap->segs;
820                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
821                         if (phdr->p_vaddr >= seg->p_vaddr &&
822                             phdr->p_vaddr + phdr->p_filesz <=
823                             seg->p_vaddr + seg->p_memsz) {
824                                 params->ph_addr =
825                                         (phdr->p_vaddr - seg->p_vaddr) +
826                                         seg->addr +
827                                         params->hdr.e_phoff - phdr->p_offset;
828                                 break;
829                         }
830                 }
831                 break;
832         }
833 
834         /* determine where the dynamic section has wound up if there is one */
835         phdr = params->phdrs;
836         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
837                 if (phdr->p_type != PT_DYNAMIC)
838                         continue;
839 
840                 seg = loadmap->segs;
841                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
842                         if (phdr->p_vaddr >= seg->p_vaddr &&
843                             phdr->p_vaddr + phdr->p_memsz <=
844                             seg->p_vaddr + seg->p_memsz) {
845                                 Elf32_Dyn __user *dyn;
846                                 Elf32_Sword d_tag;
847 
848                                 params->dynamic_addr =
849                                         (phdr->p_vaddr - seg->p_vaddr) +
850                                         seg->addr;
851 
852                                 /* check the dynamic section contains at least
853                                  * one item, and that the last item is a NULL
854                                  * entry */
855                                 if (phdr->p_memsz == 0 ||
856                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
857                                         goto dynamic_error;
858 
859                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
860                                 dyn = (Elf32_Dyn __user *)params->dynamic_addr;
861                                 if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
862                                     d_tag != 0)
863                                         goto dynamic_error;
864                                 break;
865                         }
866                 }
867                 break;
868         }
869 
870         /* now elide adjacent segments in the load map on MMU linux
871          * - on uClinux the holes between may actually be filled with system
872          *   stuff or stuff from other processes
873          */
874 #ifdef CONFIG_MMU
875         nloads = loadmap->nsegs;
876         mseg = loadmap->segs;
877         seg = mseg + 1;
878         for (loop = 1; loop < nloads; loop++) {
879                 /* see if we have a candidate for merging */
880                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
881                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
882                         if (load_addr == (seg->addr & PAGE_MASK)) {
883                                 mseg->p_memsz +=
884                                         load_addr -
885                                         (mseg->addr + mseg->p_memsz);
886                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
887                                 mseg->p_memsz += seg->p_memsz;
888                                 loadmap->nsegs--;
889                                 continue;
890                         }
891                 }
892 
893                 mseg++;
894                 if (mseg != seg)
895                         *mseg = *seg;
896         }
897 #endif
898 
899         kdebug("Mapped Object [%s]:", what);
900         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
901         kdebug("- entry    : %lx", params->entry_addr);
902         kdebug("- PHDR[]   : %lx", params->ph_addr);
903         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
904         seg = loadmap->segs;
905         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
906                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
907                        loop,
908                        seg->addr, seg->addr + seg->p_memsz - 1,
909                        seg->p_vaddr, seg->p_memsz);
910 
911         return 0;
912 
913 dynamic_error:
914         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
915                what, file_inode(file)->i_ino);
916         return -ELIBBAD;
917 }
918 
919 /*****************************************************************************/
920 /*
921  * map a file with constant displacement under uClinux
922  */
923 #ifndef CONFIG_MMU
924 static int elf_fdpic_map_file_constdisp_on_uclinux(
925         struct elf_fdpic_params *params,
926         struct file *file,
927         struct mm_struct *mm)
928 {
929         struct elf32_fdpic_loadseg *seg;
930         struct elf32_phdr *phdr;
931         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0;
932         int loop, ret;
933 
934         load_addr = params->load_addr;
935         seg = params->loadmap->segs;
936 
937         /* determine the bounds of the contiguous overall allocation we must
938          * make */
939         phdr = params->phdrs;
940         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
941                 if (params->phdrs[loop].p_type != PT_LOAD)
942                         continue;
943 
944                 if (base > phdr->p_vaddr)
945                         base = phdr->p_vaddr;
946                 if (top < phdr->p_vaddr + phdr->p_memsz)
947                         top = phdr->p_vaddr + phdr->p_memsz;
948         }
949 
950         /* allocate one big anon block for everything */
951         maddr = vm_mmap(NULL, load_addr, top - base,
952                         PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, 0);
953         if (IS_ERR_VALUE(maddr))
954                 return (int) maddr;
955 
956         if (load_addr != 0)
957                 load_addr += PAGE_ALIGN(top - base);
958 
959         /* and then load the file segments into it */
960         phdr = params->phdrs;
961         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
962                 if (params->phdrs[loop].p_type != PT_LOAD)
963                         continue;
964 
965                 seg->addr = maddr + (phdr->p_vaddr - base);
966                 seg->p_vaddr = phdr->p_vaddr;
967                 seg->p_memsz = phdr->p_memsz;
968 
969                 ret = read_code(file, seg->addr, phdr->p_offset,
970                                        phdr->p_filesz);
971                 if (ret < 0)
972                         return ret;
973 
974                 /* map the ELF header address if in this segment */
975                 if (phdr->p_offset == 0)
976                         params->elfhdr_addr = seg->addr;
977 
978                 /* clear any space allocated but not loaded */
979                 if (phdr->p_filesz < phdr->p_memsz) {
980                         if (clear_user((void *) (seg->addr + phdr->p_filesz),
981                                        phdr->p_memsz - phdr->p_filesz))
982                                 return -EFAULT;
983                 }
984 
985                 if (mm) {
986                         if (phdr->p_flags & PF_X) {
987                                 if (!mm->start_code) {
988                                         mm->start_code = seg->addr;
989                                         mm->end_code = seg->addr +
990                                                 phdr->p_memsz;
991                                 }
992                         } else if (!mm->start_data) {
993                                 mm->start_data = seg->addr;
994                                 mm->end_data = seg->addr + phdr->p_memsz;
995                         }
996                 }
997 
998                 seg++;
999         }
1000 
1001         return 0;
1002 }
1003 #endif
1004 
1005 /*****************************************************************************/
1006 /*
1007  * map a binary by direct mmap() of the individual PT_LOAD segments
1008  */
1009 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
1010                                              struct file *file,
1011                                              struct mm_struct *mm)
1012 {
1013         struct elf32_fdpic_loadseg *seg;
1014         struct elf32_phdr *phdr;
1015         unsigned long load_addr, delta_vaddr;
1016         int loop, dvset;
1017 
1018         load_addr = params->load_addr;
1019         delta_vaddr = 0;
1020         dvset = 0;
1021 
1022         seg = params->loadmap->segs;
1023 
1024         /* deal with each load segment separately */
1025         phdr = params->phdrs;
1026         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1027                 unsigned long maddr, disp, excess, excess1;
1028                 int prot = 0, flags;
1029 
1030                 if (phdr->p_type != PT_LOAD)
1031                         continue;
1032 
1033                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1034                        (unsigned long) phdr->p_vaddr,
1035                        (unsigned long) phdr->p_offset,
1036                        (unsigned long) phdr->p_filesz,
1037                        (unsigned long) phdr->p_memsz);
1038 
1039                 /* determine the mapping parameters */
1040                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1041                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1042                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1043 
1044                 flags = MAP_PRIVATE | MAP_DENYWRITE;
1045                 maddr = 0;
1046 
1047                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1048                 case ELF_FDPIC_FLAG_INDEPENDENT:
1049                         /* PT_LOADs are independently locatable */
1050                         break;
1051 
1052                 case ELF_FDPIC_FLAG_HONOURVADDR:
1053                         /* the specified virtual address must be honoured */
1054                         maddr = phdr->p_vaddr;
1055                         flags |= MAP_FIXED;
1056                         break;
1057 
1058                 case ELF_FDPIC_FLAG_CONSTDISP:
1059                         /* constant displacement
1060                          * - can be mapped anywhere, but must be mapped as a
1061                          *   unit
1062                          */
1063                         if (!dvset) {
1064                                 maddr = load_addr;
1065                                 delta_vaddr = phdr->p_vaddr;
1066                                 dvset = 1;
1067                         } else {
1068                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1069                                 flags |= MAP_FIXED;
1070                         }
1071                         break;
1072 
1073                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1074                         /* contiguity handled later */
1075                         break;
1076 
1077                 default:
1078                         BUG();
1079                 }
1080 
1081                 maddr &= PAGE_MASK;
1082 
1083                 /* create the mapping */
1084                 disp = phdr->p_vaddr & ~PAGE_MASK;
1085                 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1086                                 phdr->p_offset - disp);
1087 
1088                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1089                        loop, phdr->p_memsz + disp, prot, flags,
1090                        phdr->p_offset - disp, maddr);
1091 
1092                 if (IS_ERR_VALUE(maddr))
1093                         return (int) maddr;
1094 
1095                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1096                     ELF_FDPIC_FLAG_CONTIGUOUS)
1097                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1098 
1099                 seg->addr = maddr + disp;
1100                 seg->p_vaddr = phdr->p_vaddr;
1101                 seg->p_memsz = phdr->p_memsz;
1102 
1103                 /* map the ELF header address if in this segment */
1104                 if (phdr->p_offset == 0)
1105                         params->elfhdr_addr = seg->addr;
1106 
1107                 /* clear the bit between beginning of mapping and beginning of
1108                  * PT_LOAD */
1109                 if (prot & PROT_WRITE && disp > 0) {
1110                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1111                         if (clear_user((void __user *) maddr, disp))
1112                                 return -EFAULT;
1113                         maddr += disp;
1114                 }
1115 
1116                 /* clear any space allocated but not loaded
1117                  * - on uClinux we can just clear the lot
1118                  * - on MMU linux we'll get a SIGBUS beyond the last page
1119                  *   extant in the file
1120                  */
1121                 excess = phdr->p_memsz - phdr->p_filesz;
1122                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1123 
1124 #ifdef CONFIG_MMU
1125                 if (excess > excess1) {
1126                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1127                         unsigned long xmaddr;
1128 
1129                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1130                         xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1131                                          prot, flags, 0);
1132 
1133                         kdebug("mmap[%d] <anon>"
1134                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1135                                loop, xaddr, excess - excess1, prot, flags,
1136                                xmaddr);
1137 
1138                         if (xmaddr != xaddr)
1139                                 return -ENOMEM;
1140                 }
1141 
1142                 if (prot & PROT_WRITE && excess1 > 0) {
1143                         kdebug("clear[%d] ad=%lx sz=%lx",
1144                                loop, maddr + phdr->p_filesz, excess1);
1145                         if (clear_user((void __user *) maddr + phdr->p_filesz,
1146                                        excess1))
1147                                 return -EFAULT;
1148                 }
1149 
1150 #else
1151                 if (excess > 0) {
1152                         kdebug("clear[%d] ad=%lx sz=%lx",
1153                                loop, maddr + phdr->p_filesz, excess);
1154                         if (clear_user((void *) maddr + phdr->p_filesz, excess))
1155                                 return -EFAULT;
1156                 }
1157 #endif
1158 
1159                 if (mm) {
1160                         if (phdr->p_flags & PF_X) {
1161                                 if (!mm->start_code) {
1162                                         mm->start_code = maddr;
1163                                         mm->end_code = maddr + phdr->p_memsz;
1164                                 }
1165                         } else if (!mm->start_data) {
1166                                 mm->start_data = maddr;
1167                                 mm->end_data = maddr + phdr->p_memsz;
1168                         }
1169                 }
1170 
1171                 seg++;
1172         }
1173 
1174         return 0;
1175 }
1176 
1177 /*****************************************************************************/
1178 /*
1179  * ELF-FDPIC core dumper
1180  *
1181  * Modelled on fs/exec.c:aout_core_dump()
1182  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1183  *
1184  * Modelled on fs/binfmt_elf.c core dumper
1185  */
1186 #ifdef CONFIG_ELF_CORE
1187 
1188 struct elf_prstatus_fdpic
1189 {
1190         struct elf_prstatus_common      common;
1191         elf_gregset_t pr_reg;   /* GP registers */
1192         /* When using FDPIC, the loadmap addresses need to be communicated
1193          * to GDB in order for GDB to do the necessary relocations.  The
1194          * fields (below) used to communicate this information are placed
1195          * immediately after ``pr_reg'', so that the loadmap addresses may
1196          * be viewed as part of the register set if so desired.
1197          */
1198         unsigned long pr_exec_fdpic_loadmap;
1199         unsigned long pr_interp_fdpic_loadmap;
1200         int pr_fpvalid;         /* True if math co-processor being used.  */
1201 };
1202 
1203 /* An ELF note in memory */
1204 struct memelfnote
1205 {
1206         const char *name;
1207         int type;
1208         unsigned int datasz;
1209         void *data;
1210 };
1211 
1212 static int notesize(struct memelfnote *en)
1213 {
1214         int sz;
1215 
1216         sz = sizeof(struct elf_note);
1217         sz += roundup(strlen(en->name) + 1, 4);
1218         sz += roundup(en->datasz, 4);
1219 
1220         return sz;
1221 }
1222 
1223 /* #define DEBUG */
1224 
1225 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1226 {
1227         struct elf_note en;
1228         en.n_namesz = strlen(men->name) + 1;
1229         en.n_descsz = men->datasz;
1230         en.n_type = men->type;
1231 
1232         return dump_emit(cprm, &en, sizeof(en)) &&
1233                 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1234                 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1235 }
1236 
1237 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1238 {
1239         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1240         elf->e_ident[EI_CLASS] = ELF_CLASS;
1241         elf->e_ident[EI_DATA] = ELF_DATA;
1242         elf->e_ident[EI_VERSION] = EV_CURRENT;
1243         elf->e_ident[EI_OSABI] = ELF_OSABI;
1244         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1245 
1246         elf->e_type = ET_CORE;
1247         elf->e_machine = ELF_ARCH;
1248         elf->e_version = EV_CURRENT;
1249         elf->e_entry = 0;
1250         elf->e_phoff = sizeof(struct elfhdr);
1251         elf->e_shoff = 0;
1252         elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1253         elf->e_ehsize = sizeof(struct elfhdr);
1254         elf->e_phentsize = sizeof(struct elf_phdr);
1255         elf->e_phnum = segs;
1256         elf->e_shentsize = 0;
1257         elf->e_shnum = 0;
1258         elf->e_shstrndx = 0;
1259         return;
1260 }
1261 
1262 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1263 {
1264         phdr->p_type = PT_NOTE;
1265         phdr->p_offset = offset;
1266         phdr->p_vaddr = 0;
1267         phdr->p_paddr = 0;
1268         phdr->p_filesz = sz;
1269         phdr->p_memsz = 0;
1270         phdr->p_flags = 0;
1271         phdr->p_align = 0;
1272         return;
1273 }
1274 
1275 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1276                 unsigned int sz, void *data)
1277 {
1278         note->name = name;
1279         note->type = type;
1280         note->datasz = sz;
1281         note->data = data;
1282         return;
1283 }
1284 
1285 /*
1286  * fill up all the fields in prstatus from the given task struct, except
1287  * registers which need to be filled up separately.
1288  */
1289 static void fill_prstatus(struct elf_prstatus_common *prstatus,
1290                           struct task_struct *p, long signr)
1291 {
1292         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1293         prstatus->pr_sigpend = p->pending.signal.sig[0];
1294         prstatus->pr_sighold = p->blocked.sig[0];
1295         rcu_read_lock();
1296         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1297         rcu_read_unlock();
1298         prstatus->pr_pid = task_pid_vnr(p);
1299         prstatus->pr_pgrp = task_pgrp_vnr(p);
1300         prstatus->pr_sid = task_session_vnr(p);
1301         if (thread_group_leader(p)) {
1302                 struct task_cputime cputime;
1303 
1304                 /*
1305                  * This is the record for the group leader.  It shows the
1306                  * group-wide total, not its individual thread total.
1307                  */
1308                 thread_group_cputime(p, &cputime);
1309                 prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
1310                 prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1311         } else {
1312                 u64 utime, stime;
1313 
1314                 task_cputime(p, &utime, &stime);
1315                 prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
1316                 prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1317         }
1318         prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
1319         prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1320 }
1321 
1322 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1323                        struct mm_struct *mm)
1324 {
1325         const struct cred *cred;
1326         unsigned int i, len;
1327         unsigned int state;
1328 
1329         /* first copy the parameters from user space */
1330         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1331 
1332         len = mm->arg_end - mm->arg_start;
1333         if (len >= ELF_PRARGSZ)
1334                 len = ELF_PRARGSZ - 1;
1335         if (copy_from_user(&psinfo->pr_psargs,
1336                            (const char __user *) mm->arg_start, len))
1337                 return -EFAULT;
1338         for (i = 0; i < len; i++)
1339                 if (psinfo->pr_psargs[i] == 0)
1340                         psinfo->pr_psargs[i] = ' ';
1341         psinfo->pr_psargs[len] = 0;
1342 
1343         rcu_read_lock();
1344         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1345         rcu_read_unlock();
1346         psinfo->pr_pid = task_pid_vnr(p);
1347         psinfo->pr_pgrp = task_pgrp_vnr(p);
1348         psinfo->pr_sid = task_session_vnr(p);
1349 
1350         state = READ_ONCE(p->__state);
1351         i = state ? ffz(~state) + 1 : 0;
1352         psinfo->pr_state = i;
1353         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1354         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1355         psinfo->pr_nice = task_nice(p);
1356         psinfo->pr_flag = p->flags;
1357         rcu_read_lock();
1358         cred = __task_cred(p);
1359         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1360         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1361         rcu_read_unlock();
1362         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1363 
1364         return 0;
1365 }
1366 
1367 /* Here is the structure in which status of each thread is captured. */
1368 struct elf_thread_status
1369 {
1370         struct elf_thread_status *next;
1371         struct elf_prstatus_fdpic prstatus;     /* NT_PRSTATUS */
1372         elf_fpregset_t fpu;             /* NT_PRFPREG */
1373         struct memelfnote notes[2];
1374         int num_notes;
1375 };
1376 
1377 /*
1378  * In order to add the specific thread information for the elf file format,
1379  * we need to keep a linked list of every thread's pr_status and then create
1380  * a single section for them in the final core file.
1381  */
1382 static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_struct *p, int *sz)
1383 {
1384         const struct user_regset_view *view = task_user_regset_view(p);
1385         struct elf_thread_status *t;
1386         int i, ret;
1387 
1388         t = kzalloc(sizeof(struct elf_thread_status), GFP_KERNEL);
1389         if (!t)
1390                 return t;
1391 
1392         fill_prstatus(&t->prstatus.common, p, signr);
1393         t->prstatus.pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1394         t->prstatus.pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1395         regset_get(p, &view->regsets[0],
1396                    sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
1397 
1398         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1399                   &t->prstatus);
1400         t->num_notes++;
1401         *sz += notesize(&t->notes[0]);
1402 
1403         for (i = 1; i < view->n; ++i) {
1404                 const struct user_regset *regset = &view->regsets[i];
1405                 if (regset->core_note_type != NT_PRFPREG)
1406                         continue;
1407                 if (regset->active && regset->active(p, regset) <= 0)
1408                         continue;
1409                 ret = regset_get(p, regset, sizeof(t->fpu), &t->fpu);
1410                 if (ret >= 0)
1411                         t->prstatus.pr_fpvalid = 1;
1412                 break;
1413         }
1414 
1415         if (t->prstatus.pr_fpvalid) {
1416                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1417                           &t->fpu);
1418                 t->num_notes++;
1419                 *sz += notesize(&t->notes[1]);
1420         }
1421         return t;
1422 }
1423 
1424 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1425                              elf_addr_t e_shoff, int segs)
1426 {
1427         elf->e_shoff = e_shoff;
1428         elf->e_shentsize = sizeof(*shdr4extnum);
1429         elf->e_shnum = 1;
1430         elf->e_shstrndx = SHN_UNDEF;
1431 
1432         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1433 
1434         shdr4extnum->sh_type = SHT_NULL;
1435         shdr4extnum->sh_size = elf->e_shnum;
1436         shdr4extnum->sh_link = elf->e_shstrndx;
1437         shdr4extnum->sh_info = segs;
1438 }
1439 
1440 /*
1441  * dump the segments for an MMU process
1442  */
1443 static bool elf_fdpic_dump_segments(struct coredump_params *cprm,
1444                                     struct core_vma_metadata *vma_meta,
1445                                     int vma_count)
1446 {
1447         int i;
1448 
1449         for (i = 0; i < vma_count; i++) {
1450                 struct core_vma_metadata *meta = vma_meta + i;
1451 
1452                 if (!dump_user_range(cprm, meta->start, meta->dump_size))
1453                         return false;
1454         }
1455         return true;
1456 }
1457 
1458 /*
1459  * Actual dumper
1460  *
1461  * This is a two-pass process; first we find the offsets of the bits,
1462  * and then they are actually written out.  If we run out of core limit
1463  * we just truncate.
1464  */
1465 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1466 {
1467         int has_dumped = 0;
1468         int vma_count, segs;
1469         int i;
1470         struct elfhdr *elf = NULL;
1471         loff_t offset = 0, dataoff;
1472         struct memelfnote psinfo_note, auxv_note;
1473         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1474         struct elf_thread_status *thread_list = NULL;
1475         int thread_status_size = 0;
1476         elf_addr_t *auxv;
1477         struct elf_phdr *phdr4note = NULL;
1478         struct elf_shdr *shdr4extnum = NULL;
1479         Elf_Half e_phnum;
1480         elf_addr_t e_shoff;
1481         struct core_thread *ct;
1482         struct elf_thread_status *tmp;
1483         struct core_vma_metadata *vma_meta = NULL;
1484         size_t vma_data_size;
1485 
1486         /* alloc memory for large data structures: too large to be on stack */
1487         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1488         if (!elf)
1489                 goto end_coredump;
1490         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1491         if (!psinfo)
1492                 goto end_coredump;
1493 
1494         if (dump_vma_snapshot(cprm, &vma_count, &vma_meta, &vma_data_size))
1495                 goto end_coredump;
1496 
1497         for (ct = current->mm->core_state->dumper.next;
1498                                         ct; ct = ct->next) {
1499                 tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
1500                                              ct->task, &thread_status_size);
1501                 if (!tmp)
1502                         goto end_coredump;
1503 
1504                 tmp->next = thread_list;
1505                 thread_list = tmp;
1506         }
1507 
1508         /* now collect the dump for the current */
1509         tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
1510                                      current, &thread_status_size);
1511         if (!tmp)
1512                 goto end_coredump;
1513         tmp->next = thread_list;
1514         thread_list = tmp;
1515 
1516         segs = vma_count + elf_core_extra_phdrs();
1517 
1518         /* for notes section */
1519         segs++;
1520 
1521         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1522          * this, kernel supports extended numbering. Have a look at
1523          * include/linux/elf.h for further information. */
1524         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1525 
1526         /* Set up header */
1527         fill_elf_fdpic_header(elf, e_phnum);
1528 
1529         has_dumped = 1;
1530         /*
1531          * Set up the notes in similar form to SVR4 core dumps made
1532          * with info from their /proc.
1533          */
1534 
1535         fill_psinfo(psinfo, current->group_leader, current->mm);
1536         fill_note(&psinfo_note, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1537         thread_status_size += notesize(&psinfo_note);
1538 
1539         auxv = (elf_addr_t *) current->mm->saved_auxv;
1540         i = 0;
1541         do
1542                 i += 2;
1543         while (auxv[i - 2] != AT_NULL);
1544         fill_note(&auxv_note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1545         thread_status_size += notesize(&auxv_note);
1546 
1547         offset = sizeof(*elf);                          /* Elf header */
1548         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1549 
1550         /* Write notes phdr entry */
1551         phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1552         if (!phdr4note)
1553                 goto end_coredump;
1554 
1555         fill_elf_note_phdr(phdr4note, thread_status_size, offset);
1556         offset += thread_status_size;
1557 
1558         /* Page-align dumped data */
1559         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1560 
1561         offset += vma_data_size;
1562         offset += elf_core_extra_data_size();
1563         e_shoff = offset;
1564 
1565         if (e_phnum == PN_XNUM) {
1566                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1567                 if (!shdr4extnum)
1568                         goto end_coredump;
1569                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1570         }
1571 
1572         offset = dataoff;
1573 
1574         if (!dump_emit(cprm, elf, sizeof(*elf)))
1575                 goto end_coredump;
1576 
1577         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1578                 goto end_coredump;
1579 
1580         /* write program headers for segments dump */
1581         for (i = 0; i < vma_count; i++) {
1582                 struct core_vma_metadata *meta = vma_meta + i;
1583                 struct elf_phdr phdr;
1584                 size_t sz;
1585 
1586                 sz = meta->end - meta->start;
1587 
1588                 phdr.p_type = PT_LOAD;
1589                 phdr.p_offset = offset;
1590                 phdr.p_vaddr = meta->start;
1591                 phdr.p_paddr = 0;
1592                 phdr.p_filesz = meta->dump_size;
1593                 phdr.p_memsz = sz;
1594                 offset += phdr.p_filesz;
1595                 phdr.p_flags = 0;
1596                 if (meta->flags & VM_READ)
1597                         phdr.p_flags |= PF_R;
1598                 if (meta->flags & VM_WRITE)
1599                         phdr.p_flags |= PF_W;
1600                 if (meta->flags & VM_EXEC)
1601                         phdr.p_flags |= PF_X;
1602                 phdr.p_align = ELF_EXEC_PAGESIZE;
1603 
1604                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1605                         goto end_coredump;
1606         }
1607 
1608         if (!elf_core_write_extra_phdrs(cprm, offset))
1609                 goto end_coredump;
1610 
1611         /* write out the notes section */
1612         if (!writenote(thread_list->notes, cprm))
1613                 goto end_coredump;
1614         if (!writenote(&psinfo_note, cprm))
1615                 goto end_coredump;
1616         if (!writenote(&auxv_note, cprm))
1617                 goto end_coredump;
1618         for (i = 1; i < thread_list->num_notes; i++)
1619                 if (!writenote(thread_list->notes + i, cprm))
1620                         goto end_coredump;
1621 
1622         /* write out the thread status notes section */
1623         for (tmp = thread_list->next; tmp; tmp = tmp->next) {
1624                 for (i = 0; i < tmp->num_notes; i++)
1625                         if (!writenote(&tmp->notes[i], cprm))
1626                                 goto end_coredump;
1627         }
1628 
1629         dump_skip_to(cprm, dataoff);
1630 
1631         if (!elf_fdpic_dump_segments(cprm, vma_meta, vma_count))
1632                 goto end_coredump;
1633 
1634         if (!elf_core_write_extra_data(cprm))
1635                 goto end_coredump;
1636 
1637         if (e_phnum == PN_XNUM) {
1638                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1639                         goto end_coredump;
1640         }
1641 
1642         if (cprm->file->f_pos != offset) {
1643                 /* Sanity check */
1644                 printk(KERN_WARNING
1645                        "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1646                        cprm->file->f_pos, offset);
1647         }
1648 
1649 end_coredump:
1650         while (thread_list) {
1651                 tmp = thread_list;
1652                 thread_list = thread_list->next;
1653                 kfree(tmp);
1654         }
1655         kvfree(vma_meta);
1656         kfree(phdr4note);
1657         kfree(elf);
1658         kfree(psinfo);
1659         kfree(shdr4extnum);
1660         return has_dumped;
1661 }
1662 
1663 #endif          /* CONFIG_ELF_CORE */
1664 

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