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
39 #include <linux/uaccess.h>
40 #include <asm/param.h>
41 #include <asm/pgalloc.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
init_elf_fdpic_binfmt(void)90 static int __init init_elf_fdpic_binfmt(void)
91 {
92 register_binfmt(&elf_fdpic_format);
93 return 0;
94 }
95
exit_elf_fdpic_binfmt(void)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
is_elf(struct elfhdr * hdr,struct file * file)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
is_constdisp(struct elfhdr * hdr)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 */
elf_fdpic_fetch_phdrs(struct elf_fdpic_params * params,struct file * file)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 */
load_elf_fdpic_binary(struct linux_binprm * bprm)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 = 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 ¤t->mm->start_stack,
371 ¤t->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 install_exec_creds(bprm);
438 if (create_elf_fdpic_tables(bprm, current->mm,
439 &exec_params, &interp_params) < 0)
440 goto error;
441
442 kdebug("- start_code %lx", current->mm->start_code);
443 kdebug("- end_code %lx", current->mm->end_code);
444 kdebug("- start_data %lx", current->mm->start_data);
445 kdebug("- end_data %lx", current->mm->end_data);
446 kdebug("- start_brk %lx", current->mm->start_brk);
447 kdebug("- brk %lx", current->mm->brk);
448 kdebug("- start_stack %lx", current->mm->start_stack);
449
450 #ifdef ELF_FDPIC_PLAT_INIT
451 /*
452 * The ABI may specify that certain registers be set up in special
453 * ways (on i386 %edx is the address of a DT_FINI function, for
454 * example. This macro performs whatever initialization to
455 * the regs structure is required.
456 */
457 dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
458 ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
459 dynaddr);
460 #endif
461
462 finalize_exec(bprm);
463 /* everything is now ready... get the userspace context ready to roll */
464 entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
465 start_thread(regs, entryaddr, current->mm->start_stack);
466
467 retval = 0;
468
469 error:
470 if (interpreter) {
471 allow_write_access(interpreter);
472 fput(interpreter);
473 }
474 kfree(interpreter_name);
475 kfree(exec_params.phdrs);
476 kfree(exec_params.loadmap);
477 kfree(interp_params.phdrs);
478 kfree(interp_params.loadmap);
479 return retval;
480 }
481
482 /*****************************************************************************/
483
484 #ifndef ELF_BASE_PLATFORM
485 /*
486 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
487 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
488 * will be copied to the user stack in the same manner as AT_PLATFORM.
489 */
490 #define ELF_BASE_PLATFORM NULL
491 #endif
492
493 /*
494 * present useful information to the program by shovelling it onto the new
495 * process's stack
496 */
create_elf_fdpic_tables(struct linux_binprm * bprm,struct mm_struct * mm,struct elf_fdpic_params * exec_params,struct elf_fdpic_params * interp_params)497 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
498 struct mm_struct *mm,
499 struct elf_fdpic_params *exec_params,
500 struct elf_fdpic_params *interp_params)
501 {
502 const struct cred *cred = current_cred();
503 unsigned long sp, csp, nitems;
504 elf_caddr_t __user *argv, *envp;
505 size_t platform_len = 0, len;
506 char *k_platform, *k_base_platform;
507 char __user *u_platform, *u_base_platform, *p;
508 int loop;
509 int nr; /* reset for each csp adjustment */
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->interp_flags & BINPRM_FLAGS_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; \
608 \
609 ent = (void __user *) csp; \
610 __put_user((id), &ent[nr]._id); \
611 __put_user((val), &ent[nr]._val); \
612 nr++; \
613 } while (0)
614
615 nr = 0;
616 csp -= 2 * sizeof(unsigned long);
617 NEW_AUX_ENT(AT_NULL, 0);
618 if (k_platform) {
619 nr = 0;
620 csp -= 2 * sizeof(unsigned long);
621 NEW_AUX_ENT(AT_PLATFORM,
622 (elf_addr_t) (unsigned long) u_platform);
623 }
624
625 if (k_base_platform) {
626 nr = 0;
627 csp -= 2 * sizeof(unsigned long);
628 NEW_AUX_ENT(AT_BASE_PLATFORM,
629 (elf_addr_t) (unsigned long) u_base_platform);
630 }
631
632 if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
633 nr = 0;
634 csp -= 2 * sizeof(unsigned long);
635 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
636 }
637
638 nr = 0;
639 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
640 NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
641 #ifdef ELF_HWCAP2
642 NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
643 #endif
644 NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
645 NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
646 NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
647 NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
648 NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum);
649 NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr);
650 NEW_AUX_ENT(AT_FLAGS, 0);
651 NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr);
652 NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
653 NEW_AUX_ENT(AT_EUID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
654 NEW_AUX_ENT(AT_GID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
655 NEW_AUX_ENT(AT_EGID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
656 NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
657 NEW_AUX_ENT(AT_EXECFN, bprm->exec);
658
659 #ifdef ARCH_DLINFO
660 nr = 0;
661 csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
662
663 /* ARCH_DLINFO must come last so platform specific code can enforce
664 * special alignment requirements on the AUXV if necessary (eg. PPC).
665 */
666 ARCH_DLINFO;
667 #endif
668 #undef NEW_AUX_ENT
669
670 /* allocate room for argv[] and envv[] */
671 csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
672 envp = (elf_caddr_t __user *) csp;
673 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
674 argv = (elf_caddr_t __user *) csp;
675
676 /* stack argc */
677 csp -= sizeof(unsigned long);
678 __put_user(bprm->argc, (unsigned long __user *) csp);
679
680 BUG_ON(csp != sp);
681
682 /* fill in the argv[] array */
683 #ifdef CONFIG_MMU
684 current->mm->arg_start = bprm->p;
685 #else
686 current->mm->arg_start = current->mm->start_stack -
687 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
688 #endif
689
690 p = (char __user *) current->mm->arg_start;
691 for (loop = bprm->argc; loop > 0; loop--) {
692 __put_user((elf_caddr_t) p, argv++);
693 len = strnlen_user(p, MAX_ARG_STRLEN);
694 if (!len || len > MAX_ARG_STRLEN)
695 return -EINVAL;
696 p += len;
697 }
698 __put_user(NULL, argv);
699 current->mm->arg_end = (unsigned long) p;
700
701 /* fill in the envv[] array */
702 current->mm->env_start = (unsigned long) p;
703 for (loop = bprm->envc; loop > 0; loop--) {
704 __put_user((elf_caddr_t)(unsigned long) p, envp++);
705 len = strnlen_user(p, MAX_ARG_STRLEN);
706 if (!len || len > MAX_ARG_STRLEN)
707 return -EINVAL;
708 p += len;
709 }
710 __put_user(NULL, envp);
711 current->mm->env_end = (unsigned long) p;
712
713 mm->start_stack = (unsigned long) sp;
714 return 0;
715 }
716
717 /*****************************************************************************/
718 /*
719 * load the appropriate binary image (executable or interpreter) into memory
720 * - we assume no MMU is available
721 * - if no other PIC bits are set in params->hdr->e_flags
722 * - we assume that the LOADable segments in the binary are independently relocatable
723 * - we assume R/O executable segments are shareable
724 * - else
725 * - we assume the loadable parts of the image to require fixed displacement
726 * - the image is not shareable
727 */
elf_fdpic_map_file(struct elf_fdpic_params * params,struct file * file,struct mm_struct * mm,const char * what)728 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
729 struct file *file,
730 struct mm_struct *mm,
731 const char *what)
732 {
733 struct elf32_fdpic_loadmap *loadmap;
734 #ifdef CONFIG_MMU
735 struct elf32_fdpic_loadseg *mseg;
736 #endif
737 struct elf32_fdpic_loadseg *seg;
738 struct elf32_phdr *phdr;
739 unsigned long load_addr, stop;
740 unsigned nloads, tmp;
741 size_t size;
742 int loop, ret;
743
744 /* allocate a load map table */
745 nloads = 0;
746 for (loop = 0; loop < params->hdr.e_phnum; loop++)
747 if (params->phdrs[loop].p_type == PT_LOAD)
748 nloads++;
749
750 if (nloads == 0)
751 return -ELIBBAD;
752
753 size = sizeof(*loadmap) + nloads * sizeof(*seg);
754 loadmap = kzalloc(size, GFP_KERNEL);
755 if (!loadmap)
756 return -ENOMEM;
757
758 params->loadmap = loadmap;
759
760 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
761 loadmap->nsegs = nloads;
762
763 load_addr = params->load_addr;
764 seg = loadmap->segs;
765
766 /* map the requested LOADs into the memory space */
767 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
768 case ELF_FDPIC_FLAG_CONSTDISP:
769 case ELF_FDPIC_FLAG_CONTIGUOUS:
770 #ifndef CONFIG_MMU
771 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
772 if (ret < 0)
773 return ret;
774 break;
775 #endif
776 default:
777 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
778 if (ret < 0)
779 return ret;
780 break;
781 }
782
783 /* map the entry point */
784 if (params->hdr.e_entry) {
785 seg = loadmap->segs;
786 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
787 if (params->hdr.e_entry >= seg->p_vaddr &&
788 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
789 params->entry_addr =
790 (params->hdr.e_entry - seg->p_vaddr) +
791 seg->addr;
792 break;
793 }
794 }
795 }
796
797 /* determine where the program header table has wound up if mapped */
798 stop = params->hdr.e_phoff;
799 stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
800 phdr = params->phdrs;
801
802 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
803 if (phdr->p_type != PT_LOAD)
804 continue;
805
806 if (phdr->p_offset > params->hdr.e_phoff ||
807 phdr->p_offset + phdr->p_filesz < stop)
808 continue;
809
810 seg = loadmap->segs;
811 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
812 if (phdr->p_vaddr >= seg->p_vaddr &&
813 phdr->p_vaddr + phdr->p_filesz <=
814 seg->p_vaddr + seg->p_memsz) {
815 params->ph_addr =
816 (phdr->p_vaddr - seg->p_vaddr) +
817 seg->addr +
818 params->hdr.e_phoff - phdr->p_offset;
819 break;
820 }
821 }
822 break;
823 }
824
825 /* determine where the dynamic section has wound up if there is one */
826 phdr = params->phdrs;
827 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
828 if (phdr->p_type != PT_DYNAMIC)
829 continue;
830
831 seg = loadmap->segs;
832 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
833 if (phdr->p_vaddr >= seg->p_vaddr &&
834 phdr->p_vaddr + phdr->p_memsz <=
835 seg->p_vaddr + seg->p_memsz) {
836 Elf32_Dyn __user *dyn;
837 Elf32_Sword d_tag;
838
839 params->dynamic_addr =
840 (phdr->p_vaddr - seg->p_vaddr) +
841 seg->addr;
842
843 /* check the dynamic section contains at least
844 * one item, and that the last item is a NULL
845 * entry */
846 if (phdr->p_memsz == 0 ||
847 phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
848 goto dynamic_error;
849
850 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
851 dyn = (Elf32_Dyn __user *)params->dynamic_addr;
852 __get_user(d_tag, &dyn[tmp - 1].d_tag);
853 if (d_tag != 0)
854 goto dynamic_error;
855 break;
856 }
857 }
858 break;
859 }
860
861 /* now elide adjacent segments in the load map on MMU linux
862 * - on uClinux the holes between may actually be filled with system
863 * stuff or stuff from other processes
864 */
865 #ifdef CONFIG_MMU
866 nloads = loadmap->nsegs;
867 mseg = loadmap->segs;
868 seg = mseg + 1;
869 for (loop = 1; loop < nloads; loop++) {
870 /* see if we have a candidate for merging */
871 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
872 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
873 if (load_addr == (seg->addr & PAGE_MASK)) {
874 mseg->p_memsz +=
875 load_addr -
876 (mseg->addr + mseg->p_memsz);
877 mseg->p_memsz += seg->addr & ~PAGE_MASK;
878 mseg->p_memsz += seg->p_memsz;
879 loadmap->nsegs--;
880 continue;
881 }
882 }
883
884 mseg++;
885 if (mseg != seg)
886 *mseg = *seg;
887 }
888 #endif
889
890 kdebug("Mapped Object [%s]:", what);
891 kdebug("- elfhdr : %lx", params->elfhdr_addr);
892 kdebug("- entry : %lx", params->entry_addr);
893 kdebug("- PHDR[] : %lx", params->ph_addr);
894 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
895 seg = loadmap->segs;
896 for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
897 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
898 loop,
899 seg->addr, seg->addr + seg->p_memsz - 1,
900 seg->p_vaddr, seg->p_memsz);
901
902 return 0;
903
904 dynamic_error:
905 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
906 what, file_inode(file)->i_ino);
907 return -ELIBBAD;
908 }
909
910 /*****************************************************************************/
911 /*
912 * map a file with constant displacement under uClinux
913 */
914 #ifndef CONFIG_MMU
elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params * params,struct file * file,struct mm_struct * mm)915 static int elf_fdpic_map_file_constdisp_on_uclinux(
916 struct elf_fdpic_params *params,
917 struct file *file,
918 struct mm_struct *mm)
919 {
920 struct elf32_fdpic_loadseg *seg;
921 struct elf32_phdr *phdr;
922 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
923 int loop, ret;
924
925 load_addr = params->load_addr;
926 seg = params->loadmap->segs;
927
928 /* determine the bounds of the contiguous overall allocation we must
929 * make */
930 phdr = params->phdrs;
931 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
932 if (params->phdrs[loop].p_type != PT_LOAD)
933 continue;
934
935 if (base > phdr->p_vaddr)
936 base = phdr->p_vaddr;
937 if (top < phdr->p_vaddr + phdr->p_memsz)
938 top = phdr->p_vaddr + phdr->p_memsz;
939 }
940
941 /* allocate one big anon block for everything */
942 mflags = MAP_PRIVATE;
943 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
944 mflags |= MAP_EXECUTABLE;
945
946 maddr = vm_mmap(NULL, load_addr, top - base,
947 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
948 if (IS_ERR_VALUE(maddr))
949 return (int) maddr;
950
951 if (load_addr != 0)
952 load_addr += PAGE_ALIGN(top - base);
953
954 /* and then load the file segments into it */
955 phdr = params->phdrs;
956 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
957 if (params->phdrs[loop].p_type != PT_LOAD)
958 continue;
959
960 seg->addr = maddr + (phdr->p_vaddr - base);
961 seg->p_vaddr = phdr->p_vaddr;
962 seg->p_memsz = phdr->p_memsz;
963
964 ret = read_code(file, seg->addr, phdr->p_offset,
965 phdr->p_filesz);
966 if (ret < 0)
967 return ret;
968
969 /* map the ELF header address if in this segment */
970 if (phdr->p_offset == 0)
971 params->elfhdr_addr = seg->addr;
972
973 /* clear any space allocated but not loaded */
974 if (phdr->p_filesz < phdr->p_memsz) {
975 if (clear_user((void *) (seg->addr + phdr->p_filesz),
976 phdr->p_memsz - phdr->p_filesz))
977 return -EFAULT;
978 }
979
980 if (mm) {
981 if (phdr->p_flags & PF_X) {
982 if (!mm->start_code) {
983 mm->start_code = seg->addr;
984 mm->end_code = seg->addr +
985 phdr->p_memsz;
986 }
987 } else if (!mm->start_data) {
988 mm->start_data = seg->addr;
989 mm->end_data = seg->addr + phdr->p_memsz;
990 }
991 }
992
993 seg++;
994 }
995
996 return 0;
997 }
998 #endif
999
1000 /*****************************************************************************/
1001 /*
1002 * map a binary by direct mmap() of the individual PT_LOAD segments
1003 */
elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params * params,struct file * file,struct mm_struct * mm)1004 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
1005 struct file *file,
1006 struct mm_struct *mm)
1007 {
1008 struct elf32_fdpic_loadseg *seg;
1009 struct elf32_phdr *phdr;
1010 unsigned long load_addr, delta_vaddr;
1011 int loop, dvset;
1012
1013 load_addr = params->load_addr;
1014 delta_vaddr = 0;
1015 dvset = 0;
1016
1017 seg = params->loadmap->segs;
1018
1019 /* deal with each load segment separately */
1020 phdr = params->phdrs;
1021 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1022 unsigned long maddr, disp, excess, excess1;
1023 int prot = 0, flags;
1024
1025 if (phdr->p_type != PT_LOAD)
1026 continue;
1027
1028 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1029 (unsigned long) phdr->p_vaddr,
1030 (unsigned long) phdr->p_offset,
1031 (unsigned long) phdr->p_filesz,
1032 (unsigned long) phdr->p_memsz);
1033
1034 /* determine the mapping parameters */
1035 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1036 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1037 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1038
1039 flags = MAP_PRIVATE | MAP_DENYWRITE;
1040 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1041 flags |= MAP_EXECUTABLE;
1042
1043 maddr = 0;
1044
1045 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1046 case ELF_FDPIC_FLAG_INDEPENDENT:
1047 /* PT_LOADs are independently locatable */
1048 break;
1049
1050 case ELF_FDPIC_FLAG_HONOURVADDR:
1051 /* the specified virtual address must be honoured */
1052 maddr = phdr->p_vaddr;
1053 flags |= MAP_FIXED;
1054 break;
1055
1056 case ELF_FDPIC_FLAG_CONSTDISP:
1057 /* constant displacement
1058 * - can be mapped anywhere, but must be mapped as a
1059 * unit
1060 */
1061 if (!dvset) {
1062 maddr = load_addr;
1063 delta_vaddr = phdr->p_vaddr;
1064 dvset = 1;
1065 } else {
1066 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1067 flags |= MAP_FIXED;
1068 }
1069 break;
1070
1071 case ELF_FDPIC_FLAG_CONTIGUOUS:
1072 /* contiguity handled later */
1073 break;
1074
1075 default:
1076 BUG();
1077 }
1078
1079 maddr &= PAGE_MASK;
1080
1081 /* create the mapping */
1082 disp = phdr->p_vaddr & ~PAGE_MASK;
1083 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1084 phdr->p_offset - disp);
1085
1086 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1087 loop, phdr->p_memsz + disp, prot, flags,
1088 phdr->p_offset - disp, maddr);
1089
1090 if (IS_ERR_VALUE(maddr))
1091 return (int) maddr;
1092
1093 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1094 ELF_FDPIC_FLAG_CONTIGUOUS)
1095 load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1096
1097 seg->addr = maddr + disp;
1098 seg->p_vaddr = phdr->p_vaddr;
1099 seg->p_memsz = phdr->p_memsz;
1100
1101 /* map the ELF header address if in this segment */
1102 if (phdr->p_offset == 0)
1103 params->elfhdr_addr = seg->addr;
1104
1105 /* clear the bit between beginning of mapping and beginning of
1106 * PT_LOAD */
1107 if (prot & PROT_WRITE && disp > 0) {
1108 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1109 if (clear_user((void __user *) maddr, disp))
1110 return -EFAULT;
1111 maddr += disp;
1112 }
1113
1114 /* clear any space allocated but not loaded
1115 * - on uClinux we can just clear the lot
1116 * - on MMU linux we'll get a SIGBUS beyond the last page
1117 * extant in the file
1118 */
1119 excess = phdr->p_memsz - phdr->p_filesz;
1120 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1121
1122 #ifdef CONFIG_MMU
1123 if (excess > excess1) {
1124 unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1125 unsigned long xmaddr;
1126
1127 flags |= MAP_FIXED | MAP_ANONYMOUS;
1128 xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1129 prot, flags, 0);
1130
1131 kdebug("mmap[%d] <anon>"
1132 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1133 loop, xaddr, excess - excess1, prot, flags,
1134 xmaddr);
1135
1136 if (xmaddr != xaddr)
1137 return -ENOMEM;
1138 }
1139
1140 if (prot & PROT_WRITE && excess1 > 0) {
1141 kdebug("clear[%d] ad=%lx sz=%lx",
1142 loop, maddr + phdr->p_filesz, excess1);
1143 if (clear_user((void __user *) maddr + phdr->p_filesz,
1144 excess1))
1145 return -EFAULT;
1146 }
1147
1148 #else
1149 if (excess > 0) {
1150 kdebug("clear[%d] ad=%lx sz=%lx",
1151 loop, maddr + phdr->p_filesz, excess);
1152 if (clear_user((void *) maddr + phdr->p_filesz, excess))
1153 return -EFAULT;
1154 }
1155 #endif
1156
1157 if (mm) {
1158 if (phdr->p_flags & PF_X) {
1159 if (!mm->start_code) {
1160 mm->start_code = maddr;
1161 mm->end_code = maddr + phdr->p_memsz;
1162 }
1163 } else if (!mm->start_data) {
1164 mm->start_data = maddr;
1165 mm->end_data = maddr + phdr->p_memsz;
1166 }
1167 }
1168
1169 seg++;
1170 }
1171
1172 return 0;
1173 }
1174
1175 /*****************************************************************************/
1176 /*
1177 * ELF-FDPIC core dumper
1178 *
1179 * Modelled on fs/exec.c:aout_core_dump()
1180 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1181 *
1182 * Modelled on fs/binfmt_elf.c core dumper
1183 */
1184 #ifdef CONFIG_ELF_CORE
1185
1186 /*
1187 * Decide whether a segment is worth dumping; default is yes to be
1188 * sure (missing info is worse than too much; etc).
1189 * Personally I'd include everything, and use the coredump limit...
1190 *
1191 * I think we should skip something. But I am not sure how. H.J.
1192 */
maydump(struct vm_area_struct * vma,unsigned long mm_flags)1193 static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1194 {
1195 int dump_ok;
1196
1197 /* Do not dump I/O mapped devices or special mappings */
1198 if (vma->vm_flags & VM_IO) {
1199 kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1200 return 0;
1201 }
1202
1203 /* If we may not read the contents, don't allow us to dump
1204 * them either. "dump_write()" can't handle it anyway.
1205 */
1206 if (!(vma->vm_flags & VM_READ)) {
1207 kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1208 return 0;
1209 }
1210
1211 /* support for DAX */
1212 if (vma_is_dax(vma)) {
1213 if (vma->vm_flags & VM_SHARED) {
1214 dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
1215 kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
1216 vma->vm_flags, dump_ok ? "yes" : "no");
1217 } else {
1218 dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
1219 kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
1220 vma->vm_flags, dump_ok ? "yes" : "no");
1221 }
1222 return dump_ok;
1223 }
1224
1225 /* By default, dump shared memory if mapped from an anonymous file. */
1226 if (vma->vm_flags & VM_SHARED) {
1227 if (file_inode(vma->vm_file)->i_nlink == 0) {
1228 dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
1229 kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1230 vma->vm_flags, dump_ok ? "yes" : "no");
1231 return dump_ok;
1232 }
1233
1234 dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
1235 kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1236 vma->vm_flags, dump_ok ? "yes" : "no");
1237 return dump_ok;
1238 }
1239
1240 #ifdef CONFIG_MMU
1241 /* By default, if it hasn't been written to, don't write it out */
1242 if (!vma->anon_vma) {
1243 dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1244 kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1245 vma->vm_flags, dump_ok ? "yes" : "no");
1246 return dump_ok;
1247 }
1248 #endif
1249
1250 dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1251 kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1252 dump_ok ? "yes" : "no");
1253 return dump_ok;
1254 }
1255
1256 /* An ELF note in memory */
1257 struct memelfnote
1258 {
1259 const char *name;
1260 int type;
1261 unsigned int datasz;
1262 void *data;
1263 };
1264
notesize(struct memelfnote * en)1265 static int notesize(struct memelfnote *en)
1266 {
1267 int sz;
1268
1269 sz = sizeof(struct elf_note);
1270 sz += roundup(strlen(en->name) + 1, 4);
1271 sz += roundup(en->datasz, 4);
1272
1273 return sz;
1274 }
1275
1276 /* #define DEBUG */
1277
writenote(struct memelfnote * men,struct coredump_params * cprm)1278 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1279 {
1280 struct elf_note en;
1281 en.n_namesz = strlen(men->name) + 1;
1282 en.n_descsz = men->datasz;
1283 en.n_type = men->type;
1284
1285 return dump_emit(cprm, &en, sizeof(en)) &&
1286 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1287 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1288 }
1289
fill_elf_fdpic_header(struct elfhdr * elf,int segs)1290 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1291 {
1292 memcpy(elf->e_ident, ELFMAG, SELFMAG);
1293 elf->e_ident[EI_CLASS] = ELF_CLASS;
1294 elf->e_ident[EI_DATA] = ELF_DATA;
1295 elf->e_ident[EI_VERSION] = EV_CURRENT;
1296 elf->e_ident[EI_OSABI] = ELF_OSABI;
1297 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1298
1299 elf->e_type = ET_CORE;
1300 elf->e_machine = ELF_ARCH;
1301 elf->e_version = EV_CURRENT;
1302 elf->e_entry = 0;
1303 elf->e_phoff = sizeof(struct elfhdr);
1304 elf->e_shoff = 0;
1305 elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1306 elf->e_ehsize = sizeof(struct elfhdr);
1307 elf->e_phentsize = sizeof(struct elf_phdr);
1308 elf->e_phnum = segs;
1309 elf->e_shentsize = 0;
1310 elf->e_shnum = 0;
1311 elf->e_shstrndx = 0;
1312 return;
1313 }
1314
fill_elf_note_phdr(struct elf_phdr * phdr,int sz,loff_t offset)1315 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1316 {
1317 phdr->p_type = PT_NOTE;
1318 phdr->p_offset = offset;
1319 phdr->p_vaddr = 0;
1320 phdr->p_paddr = 0;
1321 phdr->p_filesz = sz;
1322 phdr->p_memsz = 0;
1323 phdr->p_flags = 0;
1324 phdr->p_align = 0;
1325 return;
1326 }
1327
fill_note(struct memelfnote * note,const char * name,int type,unsigned int sz,void * data)1328 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1329 unsigned int sz, void *data)
1330 {
1331 note->name = name;
1332 note->type = type;
1333 note->datasz = sz;
1334 note->data = data;
1335 return;
1336 }
1337
1338 /*
1339 * fill up all the fields in prstatus from the given task struct, except
1340 * registers which need to be filled up separately.
1341 */
fill_prstatus(struct elf_prstatus * prstatus,struct task_struct * p,long signr)1342 static void fill_prstatus(struct elf_prstatus *prstatus,
1343 struct task_struct *p, long signr)
1344 {
1345 prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1346 prstatus->pr_sigpend = p->pending.signal.sig[0];
1347 prstatus->pr_sighold = p->blocked.sig[0];
1348 rcu_read_lock();
1349 prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1350 rcu_read_unlock();
1351 prstatus->pr_pid = task_pid_vnr(p);
1352 prstatus->pr_pgrp = task_pgrp_vnr(p);
1353 prstatus->pr_sid = task_session_vnr(p);
1354 if (thread_group_leader(p)) {
1355 struct task_cputime cputime;
1356
1357 /*
1358 * This is the record for the group leader. It shows the
1359 * group-wide total, not its individual thread total.
1360 */
1361 thread_group_cputime(p, &cputime);
1362 prstatus->pr_utime = ns_to_timeval(cputime.utime);
1363 prstatus->pr_stime = ns_to_timeval(cputime.stime);
1364 } else {
1365 u64 utime, stime;
1366
1367 task_cputime(p, &utime, &stime);
1368 prstatus->pr_utime = ns_to_timeval(utime);
1369 prstatus->pr_stime = ns_to_timeval(stime);
1370 }
1371 prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
1372 prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
1373
1374 prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1375 prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1376 }
1377
fill_psinfo(struct elf_prpsinfo * psinfo,struct task_struct * p,struct mm_struct * mm)1378 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1379 struct mm_struct *mm)
1380 {
1381 const struct cred *cred;
1382 unsigned int i, len;
1383
1384 /* first copy the parameters from user space */
1385 memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1386
1387 len = mm->arg_end - mm->arg_start;
1388 if (len >= ELF_PRARGSZ)
1389 len = ELF_PRARGSZ - 1;
1390 if (copy_from_user(&psinfo->pr_psargs,
1391 (const char __user *) mm->arg_start, len))
1392 return -EFAULT;
1393 for (i = 0; i < len; i++)
1394 if (psinfo->pr_psargs[i] == 0)
1395 psinfo->pr_psargs[i] = ' ';
1396 psinfo->pr_psargs[len] = 0;
1397
1398 rcu_read_lock();
1399 psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1400 rcu_read_unlock();
1401 psinfo->pr_pid = task_pid_vnr(p);
1402 psinfo->pr_pgrp = task_pgrp_vnr(p);
1403 psinfo->pr_sid = task_session_vnr(p);
1404
1405 i = p->state ? ffz(~p->state) + 1 : 0;
1406 psinfo->pr_state = i;
1407 psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1408 psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1409 psinfo->pr_nice = task_nice(p);
1410 psinfo->pr_flag = p->flags;
1411 rcu_read_lock();
1412 cred = __task_cred(p);
1413 SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1414 SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1415 rcu_read_unlock();
1416 strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1417
1418 return 0;
1419 }
1420
1421 /* Here is the structure in which status of each thread is captured. */
1422 struct elf_thread_status
1423 {
1424 struct list_head list;
1425 struct elf_prstatus prstatus; /* NT_PRSTATUS */
1426 elf_fpregset_t fpu; /* NT_PRFPREG */
1427 struct task_struct *thread;
1428 #ifdef ELF_CORE_COPY_XFPREGS
1429 elf_fpxregset_t xfpu; /* ELF_CORE_XFPREG_TYPE */
1430 #endif
1431 struct memelfnote notes[3];
1432 int num_notes;
1433 };
1434
1435 /*
1436 * In order to add the specific thread information for the elf file format,
1437 * we need to keep a linked list of every thread's pr_status and then create
1438 * a single section for them in the final core file.
1439 */
elf_dump_thread_status(long signr,struct elf_thread_status * t)1440 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1441 {
1442 struct task_struct *p = t->thread;
1443 int sz = 0;
1444
1445 t->num_notes = 0;
1446
1447 fill_prstatus(&t->prstatus, p, signr);
1448 elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1449
1450 fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1451 &t->prstatus);
1452 t->num_notes++;
1453 sz += notesize(&t->notes[0]);
1454
1455 t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1456 if (t->prstatus.pr_fpvalid) {
1457 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1458 &t->fpu);
1459 t->num_notes++;
1460 sz += notesize(&t->notes[1]);
1461 }
1462
1463 #ifdef ELF_CORE_COPY_XFPREGS
1464 if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1465 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1466 sizeof(t->xfpu), &t->xfpu);
1467 t->num_notes++;
1468 sz += notesize(&t->notes[2]);
1469 }
1470 #endif
1471 return sz;
1472 }
1473
fill_extnum_info(struct elfhdr * elf,struct elf_shdr * shdr4extnum,elf_addr_t e_shoff,int segs)1474 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1475 elf_addr_t e_shoff, int segs)
1476 {
1477 elf->e_shoff = e_shoff;
1478 elf->e_shentsize = sizeof(*shdr4extnum);
1479 elf->e_shnum = 1;
1480 elf->e_shstrndx = SHN_UNDEF;
1481
1482 memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1483
1484 shdr4extnum->sh_type = SHT_NULL;
1485 shdr4extnum->sh_size = elf->e_shnum;
1486 shdr4extnum->sh_link = elf->e_shstrndx;
1487 shdr4extnum->sh_info = segs;
1488 }
1489
1490 /*
1491 * dump the segments for an MMU process
1492 */
elf_fdpic_dump_segments(struct coredump_params * cprm)1493 static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
1494 {
1495 struct vm_area_struct *vma;
1496
1497 for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1498 #ifdef CONFIG_MMU
1499 unsigned long addr;
1500 #endif
1501
1502 if (!maydump(vma, cprm->mm_flags))
1503 continue;
1504
1505 #ifdef CONFIG_MMU
1506 for (addr = vma->vm_start; addr < vma->vm_end;
1507 addr += PAGE_SIZE) {
1508 bool res;
1509 struct page *page = get_dump_page(addr);
1510 if (page) {
1511 void *kaddr = kmap(page);
1512 res = dump_emit(cprm, kaddr, PAGE_SIZE);
1513 kunmap(page);
1514 put_page(page);
1515 } else {
1516 res = dump_skip(cprm, PAGE_SIZE);
1517 }
1518 if (!res)
1519 return false;
1520 }
1521 #else
1522 if (!dump_emit(cprm, (void *) vma->vm_start,
1523 vma->vm_end - vma->vm_start))
1524 return false;
1525 #endif
1526 }
1527 return true;
1528 }
1529
elf_core_vma_data_size(unsigned long mm_flags)1530 static size_t elf_core_vma_data_size(unsigned long mm_flags)
1531 {
1532 struct vm_area_struct *vma;
1533 size_t size = 0;
1534
1535 for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1536 if (maydump(vma, mm_flags))
1537 size += vma->vm_end - vma->vm_start;
1538 return size;
1539 }
1540
1541 /*
1542 * Actual dumper
1543 *
1544 * This is a two-pass process; first we find the offsets of the bits,
1545 * and then they are actually written out. If we run out of core limit
1546 * we just truncate.
1547 */
elf_fdpic_core_dump(struct coredump_params * cprm)1548 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1549 {
1550 #define NUM_NOTES 6
1551 int has_dumped = 0;
1552 mm_segment_t fs;
1553 int segs;
1554 int i;
1555 struct vm_area_struct *vma;
1556 struct elfhdr *elf = NULL;
1557 loff_t offset = 0, dataoff;
1558 int numnote;
1559 struct memelfnote *notes = NULL;
1560 struct elf_prstatus *prstatus = NULL; /* NT_PRSTATUS */
1561 struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
1562 LIST_HEAD(thread_list);
1563 struct list_head *t;
1564 elf_fpregset_t *fpu = NULL;
1565 #ifdef ELF_CORE_COPY_XFPREGS
1566 elf_fpxregset_t *xfpu = NULL;
1567 #endif
1568 int thread_status_size = 0;
1569 elf_addr_t *auxv;
1570 struct elf_phdr *phdr4note = NULL;
1571 struct elf_shdr *shdr4extnum = NULL;
1572 Elf_Half e_phnum;
1573 elf_addr_t e_shoff;
1574 struct core_thread *ct;
1575 struct elf_thread_status *tmp;
1576
1577 /*
1578 * We no longer stop all VM operations.
1579 *
1580 * This is because those proceses that could possibly change map_count
1581 * or the mmap / vma pages are now blocked in do_exit on current
1582 * finishing this core dump.
1583 *
1584 * Only ptrace can touch these memory addresses, but it doesn't change
1585 * the map_count or the pages allocated. So no possibility of crashing
1586 * exists while dumping the mm->vm_next areas to the core file.
1587 */
1588
1589 /* alloc memory for large data structures: too large to be on stack */
1590 elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1591 if (!elf)
1592 goto cleanup;
1593 prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1594 if (!prstatus)
1595 goto cleanup;
1596 psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1597 if (!psinfo)
1598 goto cleanup;
1599 notes = kmalloc_array(NUM_NOTES, sizeof(struct memelfnote),
1600 GFP_KERNEL);
1601 if (!notes)
1602 goto cleanup;
1603 fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1604 if (!fpu)
1605 goto cleanup;
1606 #ifdef ELF_CORE_COPY_XFPREGS
1607 xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1608 if (!xfpu)
1609 goto cleanup;
1610 #endif
1611
1612 for (ct = current->mm->core_state->dumper.next;
1613 ct; ct = ct->next) {
1614 tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1615 if (!tmp)
1616 goto cleanup;
1617
1618 tmp->thread = ct->task;
1619 list_add(&tmp->list, &thread_list);
1620 }
1621
1622 list_for_each(t, &thread_list) {
1623 struct elf_thread_status *tmp;
1624 int sz;
1625
1626 tmp = list_entry(t, struct elf_thread_status, list);
1627 sz = elf_dump_thread_status(cprm->siginfo->si_signo, tmp);
1628 thread_status_size += sz;
1629 }
1630
1631 /* now collect the dump for the current */
1632 fill_prstatus(prstatus, current, cprm->siginfo->si_signo);
1633 elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1634
1635 segs = current->mm->map_count;
1636 segs += elf_core_extra_phdrs();
1637
1638 /* for notes section */
1639 segs++;
1640
1641 /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1642 * this, kernel supports extended numbering. Have a look at
1643 * include/linux/elf.h for further information. */
1644 e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1645
1646 /* Set up header */
1647 fill_elf_fdpic_header(elf, e_phnum);
1648
1649 has_dumped = 1;
1650 /*
1651 * Set up the notes in similar form to SVR4 core dumps made
1652 * with info from their /proc.
1653 */
1654
1655 fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1656 fill_psinfo(psinfo, current->group_leader, current->mm);
1657 fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1658
1659 numnote = 2;
1660
1661 auxv = (elf_addr_t *) current->mm->saved_auxv;
1662
1663 i = 0;
1664 do
1665 i += 2;
1666 while (auxv[i - 2] != AT_NULL);
1667 fill_note(¬es[numnote++], "CORE", NT_AUXV,
1668 i * sizeof(elf_addr_t), auxv);
1669
1670 /* Try to dump the FPU. */
1671 if ((prstatus->pr_fpvalid =
1672 elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1673 fill_note(notes + numnote++,
1674 "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1675 #ifdef ELF_CORE_COPY_XFPREGS
1676 if (elf_core_copy_task_xfpregs(current, xfpu))
1677 fill_note(notes + numnote++,
1678 "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1679 #endif
1680
1681 fs = get_fs();
1682 set_fs(KERNEL_DS);
1683
1684 offset += sizeof(*elf); /* Elf header */
1685 offset += segs * sizeof(struct elf_phdr); /* Program headers */
1686
1687 /* Write notes phdr entry */
1688 {
1689 int sz = 0;
1690
1691 for (i = 0; i < numnote; i++)
1692 sz += notesize(notes + i);
1693
1694 sz += thread_status_size;
1695
1696 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1697 if (!phdr4note)
1698 goto end_coredump;
1699
1700 fill_elf_note_phdr(phdr4note, sz, offset);
1701 offset += sz;
1702 }
1703
1704 /* Page-align dumped data */
1705 dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1706
1707 offset += elf_core_vma_data_size(cprm->mm_flags);
1708 offset += elf_core_extra_data_size();
1709 e_shoff = offset;
1710
1711 if (e_phnum == PN_XNUM) {
1712 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1713 if (!shdr4extnum)
1714 goto end_coredump;
1715 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1716 }
1717
1718 offset = dataoff;
1719
1720 if (!dump_emit(cprm, elf, sizeof(*elf)))
1721 goto end_coredump;
1722
1723 if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1724 goto end_coredump;
1725
1726 /* write program headers for segments dump */
1727 for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1728 struct elf_phdr phdr;
1729 size_t sz;
1730
1731 sz = vma->vm_end - vma->vm_start;
1732
1733 phdr.p_type = PT_LOAD;
1734 phdr.p_offset = offset;
1735 phdr.p_vaddr = vma->vm_start;
1736 phdr.p_paddr = 0;
1737 phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1738 phdr.p_memsz = sz;
1739 offset += phdr.p_filesz;
1740 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1741 if (vma->vm_flags & VM_WRITE)
1742 phdr.p_flags |= PF_W;
1743 if (vma->vm_flags & VM_EXEC)
1744 phdr.p_flags |= PF_X;
1745 phdr.p_align = ELF_EXEC_PAGESIZE;
1746
1747 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1748 goto end_coredump;
1749 }
1750
1751 if (!elf_core_write_extra_phdrs(cprm, offset))
1752 goto end_coredump;
1753
1754 /* write out the notes section */
1755 for (i = 0; i < numnote; i++)
1756 if (!writenote(notes + i, cprm))
1757 goto end_coredump;
1758
1759 /* write out the thread status notes section */
1760 list_for_each(t, &thread_list) {
1761 struct elf_thread_status *tmp =
1762 list_entry(t, struct elf_thread_status, list);
1763
1764 for (i = 0; i < tmp->num_notes; i++)
1765 if (!writenote(&tmp->notes[i], cprm))
1766 goto end_coredump;
1767 }
1768
1769 if (!dump_skip(cprm, dataoff - cprm->pos))
1770 goto end_coredump;
1771
1772 if (!elf_fdpic_dump_segments(cprm))
1773 goto end_coredump;
1774
1775 if (!elf_core_write_extra_data(cprm))
1776 goto end_coredump;
1777
1778 if (e_phnum == PN_XNUM) {
1779 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1780 goto end_coredump;
1781 }
1782
1783 if (cprm->file->f_pos != offset) {
1784 /* Sanity check */
1785 printk(KERN_WARNING
1786 "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1787 cprm->file->f_pos, offset);
1788 }
1789
1790 end_coredump:
1791 set_fs(fs);
1792
1793 cleanup:
1794 while (!list_empty(&thread_list)) {
1795 struct list_head *tmp = thread_list.next;
1796 list_del(tmp);
1797 kfree(list_entry(tmp, struct elf_thread_status, list));
1798 }
1799 kfree(phdr4note);
1800 kfree(elf);
1801 kfree(prstatus);
1802 kfree(psinfo);
1803 kfree(notes);
1804 kfree(fpu);
1805 kfree(shdr4extnum);
1806 #ifdef ELF_CORE_COPY_XFPREGS
1807 kfree(xfpu);
1808 #endif
1809 return has_dumped;
1810 #undef NUM_NOTES
1811 }
1812
1813 #endif /* CONFIG_ELF_CORE */
1814
