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/binfmts.h>
25 #include <linux/personality.h>
26 #include <linux/init.h>
27 #include <linux/jiffies.h>
28
29 #include <asm/system.h>
30 #include <asm/uaccess.h>
31 #include <asm/pgalloc.h>
32 #include <asm/cacheflush.h>
33 #include <asm/user32.h>
34 #include <asm/ia32.h>
35
36 #undef WARN_OLD
37 #undef CORE_DUMP /* definitely broken */
38
39 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
40 static int load_aout_library(struct file *);
41
42 #ifdef CORE_DUMP
43 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
44 unsigned long limit);
45
46 /*
47 * fill in the user structure for a core dump..
48 */
dump_thread32(struct pt_regs * regs,struct user32 * dump)49 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
50 {
51 u32 fs, gs;
52
53 /* changed the size calculations - should hopefully work better. lbt */
54 dump->magic = CMAGIC;
55 dump->start_code = 0;
56 dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
57 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
58 dump->u_dsize = ((unsigned long)
59 (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
60 dump->u_dsize -= dump->u_tsize;
61 dump->u_ssize = 0;
62 dump->u_debugreg[0] = current->thread.debugreg0;
63 dump->u_debugreg[1] = current->thread.debugreg1;
64 dump->u_debugreg[2] = current->thread.debugreg2;
65 dump->u_debugreg[3] = current->thread.debugreg3;
66 dump->u_debugreg[4] = 0;
67 dump->u_debugreg[5] = 0;
68 dump->u_debugreg[6] = current->thread.debugreg6;
69 dump->u_debugreg[7] = current->thread.debugreg7;
70
71 if (dump->start_stack < 0xc0000000) {
72 unsigned long tmp;
73
74 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
75 dump->u_ssize = tmp >> PAGE_SHIFT;
76 }
77
78 dump->regs.bx = regs->bx;
79 dump->regs.cx = regs->cx;
80 dump->regs.dx = regs->dx;
81 dump->regs.si = regs->si;
82 dump->regs.di = regs->di;
83 dump->regs.bp = regs->bp;
84 dump->regs.ax = regs->ax;
85 dump->regs.ds = current->thread.ds;
86 dump->regs.es = current->thread.es;
87 savesegment(fs, fs);
88 dump->regs.fs = fs;
89 savesegment(gs, gs);
90 dump->regs.gs = gs;
91 dump->regs.orig_ax = regs->orig_ax;
92 dump->regs.ip = regs->ip;
93 dump->regs.cs = regs->cs;
94 dump->regs.flags = regs->flags;
95 dump->regs.sp = regs->sp;
96 dump->regs.ss = regs->ss;
97
98 #if 1 /* FIXME */
99 dump->u_fpvalid = 0;
100 #else
101 dump->u_fpvalid = dump_fpu(regs, &dump->i387);
102 #endif
103 }
104
105 #endif
106
107 static struct linux_binfmt aout_format = {
108 .module = THIS_MODULE,
109 .load_binary = load_aout_binary,
110 .load_shlib = load_aout_library,
111 #ifdef CORE_DUMP
112 .core_dump = aout_core_dump,
113 #endif
114 .min_coredump = PAGE_SIZE
115 };
116
set_brk(unsigned long start,unsigned long end)117 static void set_brk(unsigned long start, unsigned long end)
118 {
119 start = PAGE_ALIGN(start);
120 end = PAGE_ALIGN(end);
121 if (end <= start)
122 return;
123 down_write(¤t->mm->mmap_sem);
124 do_brk(start, end - start);
125 up_write(¤t->mm->mmap_sem);
126 }
127
128 #ifdef CORE_DUMP
129 /*
130 * These are the only things you should do on a core-file: use only these
131 * macros to write out all the necessary info.
132 */
133
134 #include <linux/coredump.h>
135
136 #define DUMP_WRITE(addr, nr) \
137 if (!dump_write(file, (void *)(addr), (nr))) \
138 goto end_coredump;
139
140 #define DUMP_SEEK(offset) \
141 if (!dump_seek(file, offset)) \
142 goto end_coredump;
143
144 #define START_DATA() (u.u_tsize << PAGE_SHIFT)
145 #define START_STACK(u) (u.start_stack)
146
147 /*
148 * Routine writes a core dump image in the current directory.
149 * Currently only a stub-function.
150 *
151 * Note that setuid/setgid files won't make a core-dump if the uid/gid
152 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
153 * field, which also makes sure the core-dumps won't be recursive if the
154 * dumping of the process results in another error..
155 */
156
aout_core_dump(long signr,struct pt_regs * regs,struct file * file,unsigned long limit)157 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
158 unsigned long limit)
159 {
160 mm_segment_t fs;
161 int has_dumped = 0;
162 unsigned long dump_start, dump_size;
163 struct user32 dump;
164
165 fs = get_fs();
166 set_fs(KERNEL_DS);
167 has_dumped = 1;
168 current->flags |= PF_DUMPCORE;
169 strncpy(dump.u_comm, current->comm, sizeof(current->comm));
170 dump.u_ar0 = offsetof(struct user32, regs);
171 dump.signal = signr;
172 dump_thread32(regs, &dump);
173
174 /*
175 * If the size of the dump file exceeds the rlimit, then see
176 * what would happen if we wrote the stack, but not the data
177 * area.
178 */
179 if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
180 dump.u_dsize = 0;
181
182 /* Make sure we have enough room to write the stack and data areas. */
183 if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
184 dump.u_ssize = 0;
185
186 /* make sure we actually have a data and stack area to dump */
187 set_fs(USER_DS);
188 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
189 dump.u_dsize << PAGE_SHIFT))
190 dump.u_dsize = 0;
191 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
192 dump.u_ssize << PAGE_SHIFT))
193 dump.u_ssize = 0;
194
195 set_fs(KERNEL_DS);
196 /* struct user */
197 DUMP_WRITE(&dump, sizeof(dump));
198 /* Now dump all of the user data. Include malloced stuff as well */
199 DUMP_SEEK(PAGE_SIZE);
200 /* now we start writing out the user space info */
201 set_fs(USER_DS);
202 /* Dump the data area */
203 if (dump.u_dsize != 0) {
204 dump_start = START_DATA(dump);
205 dump_size = dump.u_dsize << PAGE_SHIFT;
206 DUMP_WRITE(dump_start, dump_size);
207 }
208 /* Now prepare to dump the stack area */
209 if (dump.u_ssize != 0) {
210 dump_start = START_STACK(dump);
211 dump_size = dump.u_ssize << PAGE_SHIFT;
212 DUMP_WRITE(dump_start, dump_size);
213 }
214 end_coredump:
215 set_fs(fs);
216 return has_dumped;
217 }
218 #endif
219
220 /*
221 * create_aout_tables() parses the env- and arg-strings in new user
222 * memory and creates the pointer tables from them, and puts their
223 * addresses on the "stack", returning the new stack pointer value.
224 */
create_aout_tables(char __user * p,struct linux_binprm * bprm)225 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
226 {
227 u32 __user *argv, *envp, *sp;
228 int argc = bprm->argc, envc = bprm->envc;
229
230 sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
231 sp -= envc+1;
232 envp = sp;
233 sp -= argc+1;
234 argv = sp;
235 put_user((unsigned long) envp, --sp);
236 put_user((unsigned long) argv, --sp);
237 put_user(argc, --sp);
238 current->mm->arg_start = (unsigned long) p;
239 while (argc-- > 0) {
240 char c;
241
242 put_user((u32)(unsigned long)p, argv++);
243 do {
244 get_user(c, p++);
245 } while (c);
246 }
247 put_user(0, argv);
248 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
249 while (envc-- > 0) {
250 char c;
251
252 put_user((u32)(unsigned long)p, envp++);
253 do {
254 get_user(c, p++);
255 } while (c);
256 }
257 put_user(0, envp);
258 current->mm->env_end = (unsigned long) p;
259 return sp;
260 }
261
262 /*
263 * These are the functions used to load a.out style executables and shared
264 * libraries. There is no binary dependent code anywhere else.
265 */
load_aout_binary(struct linux_binprm * bprm,struct pt_regs * regs)266 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
267 {
268 unsigned long error, fd_offset, rlim;
269 struct exec ex;
270 int retval;
271
272 ex = *((struct exec *) bprm->buf); /* exec-header */
273 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
274 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
275 N_TRSIZE(ex) || N_DRSIZE(ex) ||
276 i_size_read(bprm->file->f_path.dentry->d_inode) <
277 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
278 return -ENOEXEC;
279 }
280
281 fd_offset = N_TXTOFF(ex);
282
283 /* Check initial limits. This avoids letting people circumvent
284 * size limits imposed on them by creating programs with large
285 * arrays in the data or bss.
286 */
287 rlim = rlimit(RLIMIT_DATA);
288 if (rlim >= RLIM_INFINITY)
289 rlim = ~0;
290 if (ex.a_data + ex.a_bss > rlim)
291 return -ENOMEM;
292
293 /* Flush all traces of the currently running executable */
294 retval = flush_old_exec(bprm);
295 if (retval)
296 return retval;
297
298 /* OK, This is the point of no return */
299 set_personality(PER_LINUX);
300 set_thread_flag(TIF_IA32);
301 current->mm->context.ia32_compat = 1;
302
303 setup_new_exec(bprm);
304
305 regs->cs = __USER32_CS;
306 regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
307 regs->r13 = regs->r14 = regs->r15 = 0;
308
309 current->mm->end_code = ex.a_text +
310 (current->mm->start_code = N_TXTADDR(ex));
311 current->mm->end_data = ex.a_data +
312 (current->mm->start_data = N_DATADDR(ex));
313 current->mm->brk = ex.a_bss +
314 (current->mm->start_brk = N_BSSADDR(ex));
315 current->mm->free_area_cache = TASK_UNMAPPED_BASE;
316 current->mm->cached_hole_size = 0;
317
318 install_exec_creds(bprm);
319 current->flags &= ~PF_FORKNOEXEC;
320
321 if (N_MAGIC(ex) == OMAGIC) {
322 unsigned long text_addr, map_size;
323 loff_t pos;
324
325 text_addr = N_TXTADDR(ex);
326
327 pos = 32;
328 map_size = ex.a_text+ex.a_data;
329
330 down_write(¤t->mm->mmap_sem);
331 error = do_brk(text_addr & PAGE_MASK, map_size);
332 up_write(¤t->mm->mmap_sem);
333
334 if (error != (text_addr & PAGE_MASK)) {
335 send_sig(SIGKILL, current, 0);
336 return error;
337 }
338
339 error = bprm->file->f_op->read(bprm->file,
340 (char __user *)text_addr,
341 ex.a_text+ex.a_data, &pos);
342 if ((signed long)error < 0) {
343 send_sig(SIGKILL, current, 0);
344 return error;
345 }
346
347 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
348 } else {
349 #ifdef WARN_OLD
350 static unsigned long error_time, error_time2;
351 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
352 (N_MAGIC(ex) != NMAGIC) &&
353 time_after(jiffies, error_time2 + 5*HZ)) {
354 printk(KERN_NOTICE "executable not page aligned\n");
355 error_time2 = jiffies;
356 }
357
358 if ((fd_offset & ~PAGE_MASK) != 0 &&
359 time_after(jiffies, error_time + 5*HZ)) {
360 printk(KERN_WARNING
361 "fd_offset is not page aligned. Please convert "
362 "program: %s\n",
363 bprm->file->f_path.dentry->d_name.name);
364 error_time = jiffies;
365 }
366 #endif
367
368 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
369 loff_t pos = fd_offset;
370
371 down_write(¤t->mm->mmap_sem);
372 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
373 up_write(¤t->mm->mmap_sem);
374 bprm->file->f_op->read(bprm->file,
375 (char __user *)N_TXTADDR(ex),
376 ex.a_text+ex.a_data, &pos);
377 flush_icache_range((unsigned long) N_TXTADDR(ex),
378 (unsigned long) N_TXTADDR(ex) +
379 ex.a_text+ex.a_data);
380 goto beyond_if;
381 }
382
383 down_write(¤t->mm->mmap_sem);
384 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
385 PROT_READ | PROT_EXEC,
386 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
387 MAP_EXECUTABLE | MAP_32BIT,
388 fd_offset);
389 up_write(¤t->mm->mmap_sem);
390
391 if (error != N_TXTADDR(ex)) {
392 send_sig(SIGKILL, current, 0);
393 return error;
394 }
395
396 down_write(¤t->mm->mmap_sem);
397 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
398 PROT_READ | PROT_WRITE | PROT_EXEC,
399 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
400 MAP_EXECUTABLE | MAP_32BIT,
401 fd_offset + ex.a_text);
402 up_write(¤t->mm->mmap_sem);
403 if (error != N_DATADDR(ex)) {
404 send_sig(SIGKILL, current, 0);
405 return error;
406 }
407 }
408 beyond_if:
409 set_binfmt(&aout_format);
410
411 set_brk(current->mm->start_brk, current->mm->brk);
412
413 retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
414 if (retval < 0) {
415 /* Someone check-me: is this error path enough? */
416 send_sig(SIGKILL, current, 0);
417 return retval;
418 }
419
420 current->mm->start_stack =
421 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
422 /* start thread */
423 loadsegment(fs, 0);
424 loadsegment(ds, __USER32_DS);
425 loadsegment(es, __USER32_DS);
426 load_gs_index(0);
427 (regs)->ip = ex.a_entry;
428 (regs)->sp = current->mm->start_stack;
429 (regs)->flags = 0x200;
430 (regs)->cs = __USER32_CS;
431 (regs)->ss = __USER32_DS;
432 regs->r8 = regs->r9 = regs->r10 = regs->r11 =
433 regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
434 set_fs(USER_DS);
435 return 0;
436 }
437
load_aout_library(struct file * file)438 static int load_aout_library(struct file *file)
439 {
440 struct inode *inode;
441 unsigned long bss, start_addr, len, error;
442 int retval;
443 struct exec ex;
444
445 inode = file->f_path.dentry->d_inode;
446
447 retval = -ENOEXEC;
448 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
449 if (error != sizeof(ex))
450 goto out;
451
452 /* We come in here for the regular a.out style of shared libraries */
453 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
454 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
455 i_size_read(inode) <
456 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
457 goto out;
458 }
459
460 if (N_FLAGS(ex))
461 goto out;
462
463 /* For QMAGIC, the starting address is 0x20 into the page. We mask
464 this off to get the starting address for the page */
465
466 start_addr = ex.a_entry & 0xfffff000;
467
468 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
469 loff_t pos = N_TXTOFF(ex);
470
471 #ifdef WARN_OLD
472 static unsigned long error_time;
473 if (time_after(jiffies, error_time + 5*HZ)) {
474 printk(KERN_WARNING
475 "N_TXTOFF is not page aligned. Please convert "
476 "library: %s\n",
477 file->f_path.dentry->d_name.name);
478 error_time = jiffies;
479 }
480 #endif
481 down_write(¤t->mm->mmap_sem);
482 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
483 up_write(¤t->mm->mmap_sem);
484
485 file->f_op->read(file, (char __user *)start_addr,
486 ex.a_text + ex.a_data, &pos);
487 flush_icache_range((unsigned long) start_addr,
488 (unsigned long) start_addr + ex.a_text +
489 ex.a_data);
490
491 retval = 0;
492 goto out;
493 }
494 /* Now use mmap to map the library into memory. */
495 down_write(¤t->mm->mmap_sem);
496 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
497 PROT_READ | PROT_WRITE | PROT_EXEC,
498 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
499 N_TXTOFF(ex));
500 up_write(¤t->mm->mmap_sem);
501 retval = error;
502 if (error != start_addr)
503 goto out;
504
505 len = PAGE_ALIGN(ex.a_text + ex.a_data);
506 bss = ex.a_text + ex.a_data + ex.a_bss;
507 if (bss > len) {
508 down_write(¤t->mm->mmap_sem);
509 error = do_brk(start_addr + len, bss - len);
510 up_write(¤t->mm->mmap_sem);
511 retval = error;
512 if (error != start_addr + len)
513 goto out;
514 }
515 retval = 0;
516 out:
517 return retval;
518 }
519
init_aout_binfmt(void)520 static int __init init_aout_binfmt(void)
521 {
522 return register_binfmt(&aout_format);
523 }
524
exit_aout_binfmt(void)525 static void __exit exit_aout_binfmt(void)
526 {
527 unregister_binfmt(&aout_format);
528 }
529
530 module_init(init_aout_binfmt);
531 module_exit(exit_aout_binfmt);
532 MODULE_LICENSE("GPL");
533