1 /*
2 * a.out loader for x86-64
3 *
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
5 * Hacked together by Andi Kleen
6 */
7
8 #include <linux/module.h>
9
10 #include <linux/time.h>
11 #include <linux/kernel.h>
12 #include <linux/mm.h>
13 #include <linux/mman.h>
14 #include <linux/a.out.h>
15 #include <linux/errno.h>
16 #include <linux/signal.h>
17 #include <linux/string.h>
18 #include <linux/fs.h>
19 #include <linux/file.h>
20 #include <linux/stat.h>
21 #include <linux/fcntl.h>
22 #include <linux/ptrace.h>
23 #include <linux/user.h>
24 #include <linux/slab.h>
25 #include <linux/binfmts.h>
26 #include <linux/personality.h>
27 #include <linux/init.h>
28 #include <linux/jiffies.h>
29
30 #include <asm/system.h>
31 #include <asm/uaccess.h>
32 #include <asm/pgalloc.h>
33 #include <asm/cacheflush.h>
34 #include <asm/user32.h>
35 #include <asm/ia32.h>
36
37 #undef WARN_OLD
38 #undef CORE_DUMP /* probably broken */
39
40 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
41 static int load_aout_library(struct file *);
42
43 #ifdef CORE_DUMP
44 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
45 unsigned long limit);
46
47 /*
48 * fill in the user structure for a core dump..
49 */
dump_thread32(struct pt_regs * regs,struct user32 * dump)50 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
51 {
52 u32 fs, gs;
53
54 /* changed the size calculations - should hopefully work better. lbt */
55 dump->magic = CMAGIC;
56 dump->start_code = 0;
57 dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
58 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
59 dump->u_dsize = ((unsigned long)
60 (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
61 dump->u_dsize -= dump->u_tsize;
62 dump->u_ssize = 0;
63 dump->u_debugreg[0] = current->thread.debugreg0;
64 dump->u_debugreg[1] = current->thread.debugreg1;
65 dump->u_debugreg[2] = current->thread.debugreg2;
66 dump->u_debugreg[3] = current->thread.debugreg3;
67 dump->u_debugreg[4] = 0;
68 dump->u_debugreg[5] = 0;
69 dump->u_debugreg[6] = current->thread.debugreg6;
70 dump->u_debugreg[7] = current->thread.debugreg7;
71
72 if (dump->start_stack < 0xc0000000) {
73 unsigned long tmp;
74
75 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
76 dump->u_ssize = tmp >> PAGE_SHIFT;
77 }
78
79 dump->regs.bx = regs->bx;
80 dump->regs.cx = regs->cx;
81 dump->regs.dx = regs->dx;
82 dump->regs.si = regs->si;
83 dump->regs.di = regs->di;
84 dump->regs.bp = regs->bp;
85 dump->regs.ax = regs->ax;
86 dump->regs.ds = current->thread.ds;
87 dump->regs.es = current->thread.es;
88 savesegment(fs, fs);
89 dump->regs.fs = fs;
90 savesegment(gs, gs);
91 dump->regs.gs = gs;
92 dump->regs.orig_ax = regs->orig_ax;
93 dump->regs.ip = regs->ip;
94 dump->regs.cs = regs->cs;
95 dump->regs.flags = regs->flags;
96 dump->regs.sp = regs->sp;
97 dump->regs.ss = regs->ss;
98
99 #if 1 /* FIXME */
100 dump->u_fpvalid = 0;
101 #else
102 dump->u_fpvalid = dump_fpu(regs, &dump->i387);
103 #endif
104 }
105
106 #endif
107
108 static struct linux_binfmt aout_format = {
109 .module = THIS_MODULE,
110 .load_binary = load_aout_binary,
111 .load_shlib = load_aout_library,
112 #ifdef CORE_DUMP
113 .core_dump = aout_core_dump,
114 #endif
115 .min_coredump = PAGE_SIZE
116 };
117
set_brk(unsigned long start,unsigned long end)118 static void set_brk(unsigned long start, unsigned long end)
119 {
120 start = PAGE_ALIGN(start);
121 end = PAGE_ALIGN(end);
122 if (end <= start)
123 return;
124 down_write(¤t->mm->mmap_sem);
125 do_brk(start, end - start);
126 up_write(¤t->mm->mmap_sem);
127 }
128
129 #ifdef CORE_DUMP
130 /*
131 * These are the only things you should do on a core-file: use only these
132 * macros to write out all the necessary info.
133 */
134
dump_write(struct file * file,const void * addr,int nr)135 static int dump_write(struct file *file, const void *addr, int nr)
136 {
137 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
138 }
139
140 #define DUMP_WRITE(addr, nr) \
141 if (!dump_write(file, (void *)(addr), (nr))) \
142 goto end_coredump;
143
144 #define DUMP_SEEK(offset) \
145 if (file->f_op->llseek) { \
146 if (file->f_op->llseek(file, (offset), 0) != (offset)) \
147 goto end_coredump; \
148 } else \
149 file->f_pos = (offset)
150
151 #define START_DATA() (u.u_tsize << PAGE_SHIFT)
152 #define START_STACK(u) (u.start_stack)
153
154 /*
155 * Routine writes a core dump image in the current directory.
156 * Currently only a stub-function.
157 *
158 * Note that setuid/setgid files won't make a core-dump if the uid/gid
159 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
160 * field, which also makes sure the core-dumps won't be recursive if the
161 * dumping of the process results in another error..
162 */
163
aout_core_dump(long signr,struct pt_regs * regs,struct file * file,unsigned long limit)164 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
165 unsigned long limit)
166 {
167 mm_segment_t fs;
168 int has_dumped = 0;
169 unsigned long dump_start, dump_size;
170 struct user32 dump;
171
172 fs = get_fs();
173 set_fs(KERNEL_DS);
174 has_dumped = 1;
175 current->flags |= PF_DUMPCORE;
176 strncpy(dump.u_comm, current->comm, sizeof(current->comm));
177 dump.u_ar0 = offsetof(struct user32, regs);
178 dump.signal = signr;
179 dump_thread32(regs, &dump);
180
181 /*
182 * If the size of the dump file exceeds the rlimit, then see
183 * what would happen if we wrote the stack, but not the data
184 * area.
185 */
186 if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
187 dump.u_dsize = 0;
188
189 /* Make sure we have enough room to write the stack and data areas. */
190 if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
191 dump.u_ssize = 0;
192
193 /* make sure we actually have a data and stack area to dump */
194 set_fs(USER_DS);
195 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
196 dump.u_dsize << PAGE_SHIFT))
197 dump.u_dsize = 0;
198 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
199 dump.u_ssize << PAGE_SHIFT))
200 dump.u_ssize = 0;
201
202 set_fs(KERNEL_DS);
203 /* struct user */
204 DUMP_WRITE(&dump, sizeof(dump));
205 /* Now dump all of the user data. Include malloced stuff as well */
206 DUMP_SEEK(PAGE_SIZE);
207 /* now we start writing out the user space info */
208 set_fs(USER_DS);
209 /* Dump the data area */
210 if (dump.u_dsize != 0) {
211 dump_start = START_DATA(dump);
212 dump_size = dump.u_dsize << PAGE_SHIFT;
213 DUMP_WRITE(dump_start, dump_size);
214 }
215 /* Now prepare to dump the stack area */
216 if (dump.u_ssize != 0) {
217 dump_start = START_STACK(dump);
218 dump_size = dump.u_ssize << PAGE_SHIFT;
219 DUMP_WRITE(dump_start, dump_size);
220 }
221 /*
222 * Finally dump the task struct. Not be used by gdb, but
223 * could be useful
224 */
225 set_fs(KERNEL_DS);
226 DUMP_WRITE(current, sizeof(*current));
227 end_coredump:
228 set_fs(fs);
229 return has_dumped;
230 }
231 #endif
232
233 /*
234 * create_aout_tables() parses the env- and arg-strings in new user
235 * memory and creates the pointer tables from them, and puts their
236 * addresses on the "stack", returning the new stack pointer value.
237 */
create_aout_tables(char __user * p,struct linux_binprm * bprm)238 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
239 {
240 u32 __user *argv, *envp, *sp;
241 int argc = bprm->argc, envc = bprm->envc;
242
243 sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
244 sp -= envc+1;
245 envp = sp;
246 sp -= argc+1;
247 argv = sp;
248 put_user((unsigned long) envp, --sp);
249 put_user((unsigned long) argv, --sp);
250 put_user(argc, --sp);
251 current->mm->arg_start = (unsigned long) p;
252 while (argc-- > 0) {
253 char c;
254
255 put_user((u32)(unsigned long)p, argv++);
256 do {
257 get_user(c, p++);
258 } while (c);
259 }
260 put_user(0, argv);
261 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
262 while (envc-- > 0) {
263 char c;
264
265 put_user((u32)(unsigned long)p, envp++);
266 do {
267 get_user(c, p++);
268 } while (c);
269 }
270 put_user(0, envp);
271 current->mm->env_end = (unsigned long) p;
272 return sp;
273 }
274
275 /*
276 * These are the functions used to load a.out style executables and shared
277 * libraries. There is no binary dependent code anywhere else.
278 */
load_aout_binary(struct linux_binprm * bprm,struct pt_regs * regs)279 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
280 {
281 unsigned long error, fd_offset, rlim;
282 struct exec ex;
283 int retval;
284
285 ex = *((struct exec *) bprm->buf); /* exec-header */
286 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
287 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
288 N_TRSIZE(ex) || N_DRSIZE(ex) ||
289 i_size_read(bprm->file->f_path.dentry->d_inode) <
290 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
291 return -ENOEXEC;
292 }
293
294 fd_offset = N_TXTOFF(ex);
295
296 /* Check initial limits. This avoids letting people circumvent
297 * size limits imposed on them by creating programs with large
298 * arrays in the data or bss.
299 */
300 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
301 if (rlim >= RLIM_INFINITY)
302 rlim = ~0;
303 if (ex.a_data + ex.a_bss > rlim)
304 return -ENOMEM;
305
306 /* Flush all traces of the currently running executable */
307 retval = flush_old_exec(bprm);
308 if (retval)
309 return retval;
310
311 regs->cs = __USER32_CS;
312 regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
313 regs->r13 = regs->r14 = regs->r15 = 0;
314
315 /* OK, This is the point of no return */
316 set_personality(PER_LINUX);
317 set_thread_flag(TIF_IA32);
318 clear_thread_flag(TIF_ABI_PENDING);
319
320 current->mm->end_code = ex.a_text +
321 (current->mm->start_code = N_TXTADDR(ex));
322 current->mm->end_data = ex.a_data +
323 (current->mm->start_data = N_DATADDR(ex));
324 current->mm->brk = ex.a_bss +
325 (current->mm->start_brk = N_BSSADDR(ex));
326 current->mm->free_area_cache = TASK_UNMAPPED_BASE;
327 current->mm->cached_hole_size = 0;
328
329 current->mm->mmap = NULL;
330 install_exec_creds(bprm);
331 current->flags &= ~PF_FORKNOEXEC;
332
333 if (N_MAGIC(ex) == OMAGIC) {
334 unsigned long text_addr, map_size;
335 loff_t pos;
336
337 text_addr = N_TXTADDR(ex);
338
339 pos = 32;
340 map_size = ex.a_text+ex.a_data;
341
342 down_write(¤t->mm->mmap_sem);
343 error = do_brk(text_addr & PAGE_MASK, map_size);
344 up_write(¤t->mm->mmap_sem);
345
346 if (error != (text_addr & PAGE_MASK)) {
347 send_sig(SIGKILL, current, 0);
348 return error;
349 }
350
351 error = bprm->file->f_op->read(bprm->file,
352 (char __user *)text_addr,
353 ex.a_text+ex.a_data, &pos);
354 if ((signed long)error < 0) {
355 send_sig(SIGKILL, current, 0);
356 return error;
357 }
358
359 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
360 } else {
361 #ifdef WARN_OLD
362 static unsigned long error_time, error_time2;
363 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
364 (N_MAGIC(ex) != NMAGIC) &&
365 time_after(jiffies, error_time2 + 5*HZ)) {
366 printk(KERN_NOTICE "executable not page aligned\n");
367 error_time2 = jiffies;
368 }
369
370 if ((fd_offset & ~PAGE_MASK) != 0 &&
371 time_after(jiffies, error_time + 5*HZ)) {
372 printk(KERN_WARNING
373 "fd_offset is not page aligned. Please convert "
374 "program: %s\n",
375 bprm->file->f_path.dentry->d_name.name);
376 error_time = jiffies;
377 }
378 #endif
379
380 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
381 loff_t pos = fd_offset;
382
383 down_write(¤t->mm->mmap_sem);
384 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
385 up_write(¤t->mm->mmap_sem);
386 bprm->file->f_op->read(bprm->file,
387 (char __user *)N_TXTADDR(ex),
388 ex.a_text+ex.a_data, &pos);
389 flush_icache_range((unsigned long) N_TXTADDR(ex),
390 (unsigned long) N_TXTADDR(ex) +
391 ex.a_text+ex.a_data);
392 goto beyond_if;
393 }
394
395 down_write(¤t->mm->mmap_sem);
396 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
397 PROT_READ | PROT_EXEC,
398 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
399 MAP_EXECUTABLE | MAP_32BIT,
400 fd_offset);
401 up_write(¤t->mm->mmap_sem);
402
403 if (error != N_TXTADDR(ex)) {
404 send_sig(SIGKILL, current, 0);
405 return error;
406 }
407
408 down_write(¤t->mm->mmap_sem);
409 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
410 PROT_READ | PROT_WRITE | PROT_EXEC,
411 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
412 MAP_EXECUTABLE | MAP_32BIT,
413 fd_offset + ex.a_text);
414 up_write(¤t->mm->mmap_sem);
415 if (error != N_DATADDR(ex)) {
416 send_sig(SIGKILL, current, 0);
417 return error;
418 }
419 }
420 beyond_if:
421 set_binfmt(&aout_format);
422
423 set_brk(current->mm->start_brk, current->mm->brk);
424
425 retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
426 if (retval < 0) {
427 /* Someone check-me: is this error path enough? */
428 send_sig(SIGKILL, current, 0);
429 return retval;
430 }
431
432 current->mm->start_stack =
433 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
434 /* start thread */
435 loadsegment(fs, 0);
436 loadsegment(ds, __USER32_DS);
437 loadsegment(es, __USER32_DS);
438 load_gs_index(0);
439 (regs)->ip = ex.a_entry;
440 (regs)->sp = current->mm->start_stack;
441 (regs)->flags = 0x200;
442 (regs)->cs = __USER32_CS;
443 (regs)->ss = __USER32_DS;
444 regs->r8 = regs->r9 = regs->r10 = regs->r11 =
445 regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
446 set_fs(USER_DS);
447 return 0;
448 }
449
load_aout_library(struct file * file)450 static int load_aout_library(struct file *file)
451 {
452 struct inode *inode;
453 unsigned long bss, start_addr, len, error;
454 int retval;
455 struct exec ex;
456
457 inode = file->f_path.dentry->d_inode;
458
459 retval = -ENOEXEC;
460 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
461 if (error != sizeof(ex))
462 goto out;
463
464 /* We come in here for the regular a.out style of shared libraries */
465 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
466 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
467 i_size_read(inode) <
468 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
469 goto out;
470 }
471
472 if (N_FLAGS(ex))
473 goto out;
474
475 /* For QMAGIC, the starting address is 0x20 into the page. We mask
476 this off to get the starting address for the page */
477
478 start_addr = ex.a_entry & 0xfffff000;
479
480 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
481 loff_t pos = N_TXTOFF(ex);
482
483 #ifdef WARN_OLD
484 static unsigned long error_time;
485 if (time_after(jiffies, error_time + 5*HZ)) {
486 printk(KERN_WARNING
487 "N_TXTOFF is not page aligned. Please convert "
488 "library: %s\n",
489 file->f_path.dentry->d_name.name);
490 error_time = jiffies;
491 }
492 #endif
493 down_write(¤t->mm->mmap_sem);
494 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
495 up_write(¤t->mm->mmap_sem);
496
497 file->f_op->read(file, (char __user *)start_addr,
498 ex.a_text + ex.a_data, &pos);
499 flush_icache_range((unsigned long) start_addr,
500 (unsigned long) start_addr + ex.a_text +
501 ex.a_data);
502
503 retval = 0;
504 goto out;
505 }
506 /* Now use mmap to map the library into memory. */
507 down_write(¤t->mm->mmap_sem);
508 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
509 PROT_READ | PROT_WRITE | PROT_EXEC,
510 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
511 N_TXTOFF(ex));
512 up_write(¤t->mm->mmap_sem);
513 retval = error;
514 if (error != start_addr)
515 goto out;
516
517 len = PAGE_ALIGN(ex.a_text + ex.a_data);
518 bss = ex.a_text + ex.a_data + ex.a_bss;
519 if (bss > len) {
520 down_write(¤t->mm->mmap_sem);
521 error = do_brk(start_addr + len, bss - len);
522 up_write(¤t->mm->mmap_sem);
523 retval = error;
524 if (error != start_addr + len)
525 goto out;
526 }
527 retval = 0;
528 out:
529 return retval;
530 }
531
init_aout_binfmt(void)532 static int __init init_aout_binfmt(void)
533 {
534 return register_binfmt(&aout_format);
535 }
536
exit_aout_binfmt(void)537 static void __exit exit_aout_binfmt(void)
538 {
539 unregister_binfmt(&aout_format);
540 }
541
542 module_init(init_aout_binfmt);
543 module_exit(exit_aout_binfmt);
544 MODULE_LICENSE("GPL");
545