1 /*
2 * linux/fs/binfmt_aout.c
3 *
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
5 */
6
7 #include <linux/module.h>
8
9 #include <linux/sched.h>
10 #include <linux/kernel.h>
11 #include <linux/mm.h>
12 #include <linux/mman.h>
13 #include <linux/a.out.h>
14 #include <linux/errno.h>
15 #include <linux/signal.h>
16 #include <linux/string.h>
17 #include <linux/fs.h>
18 #include <linux/file.h>
19 #include <linux/stat.h>
20 #include <linux/fcntl.h>
21 #include <linux/ptrace.h>
22 #include <linux/user.h>
23 #include <linux/slab.h>
24 #include <linux/binfmts.h>
25 #include <linux/personality.h>
26 #include <linux/init.h>
27
28 #include <asm/system.h>
29 #include <asm/uaccess.h>
30 #include <asm/pgalloc.h>
31
32 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
33 static int load_aout_library(struct file*);
34 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
35
36 extern void dump_thread(struct pt_regs *, struct user *);
37
38 static struct linux_binfmt aout_format = {
39 NULL, THIS_MODULE, load_aout_binary, load_aout_library, aout_core_dump, PAGE_SIZE
40 };
41
42 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
43
set_brk(unsigned long start,unsigned long end)44 static int set_brk(unsigned long start, unsigned long end)
45 {
46 start = PAGE_ALIGN(start);
47 end = PAGE_ALIGN(end);
48 if (end > start) {
49 unsigned long addr;
50 down_write(¤t->mm->mmap_sem);
51 addr = do_brk(start, end - start);
52 up_write(¤t->mm->mmap_sem);
53 if (BAD_ADDR(addr))
54 return addr;
55 }
56 return 0;
57 }
58
59 /*
60 * These are the only things you should do on a core-file: use only these
61 * macros to write out all the necessary info.
62 */
63
dump_write(struct file * file,const void * addr,int nr)64 static int dump_write(struct file *file, const void *addr, int nr)
65 {
66 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
67 }
68
69 #define DUMP_WRITE(addr, nr) \
70 if (!dump_write(file, (void *)(addr), (nr))) \
71 goto end_coredump;
72
73 #define DUMP_SEEK(offset) \
74 if (file->f_op->llseek) { \
75 if (file->f_op->llseek(file,(offset),0) != (offset)) \
76 goto end_coredump; \
77 } else file->f_pos = (offset)
78
79 /*
80 * Routine writes a core dump image in the current directory.
81 * Currently only a stub-function.
82 *
83 * Note that setuid/setgid files won't make a core-dump if the uid/gid
84 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
85 * field, which also makes sure the core-dumps won't be recursive if the
86 * dumping of the process results in another error..
87 */
88
aout_core_dump(long signr,struct pt_regs * regs,struct file * file)89 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
90 {
91 mm_segment_t fs;
92 int has_dumped = 0;
93 unsigned long dump_start, dump_size;
94 struct user dump;
95 #if defined(__alpha__)
96 # define START_DATA(u) (u.start_data)
97 #elif defined(__arm__)
98 # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
99 #elif defined(__sparc__)
100 # define START_DATA(u) (u.u_tsize)
101 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
102 # define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
103 #endif
104 #ifdef __sparc__
105 # define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
106 #else
107 # define START_STACK(u) (u.start_stack)
108 #endif
109
110 fs = get_fs();
111 set_fs(KERNEL_DS);
112 has_dumped = 1;
113 current->flags |= PF_DUMPCORE;
114 strncpy(dump.u_comm, current->comm, sizeof(current->comm));
115 #ifndef __sparc__
116 dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
117 #endif
118 dump.signal = signr;
119 dump_thread(regs, &dump);
120
121 /* If the size of the dump file exceeds the rlimit, then see what would happen
122 if we wrote the stack, but not the data area. */
123 #ifdef __sparc__
124 if ((dump.u_dsize+dump.u_ssize) >
125 current->rlim[RLIMIT_CORE].rlim_cur)
126 dump.u_dsize = 0;
127 #else
128 if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
129 current->rlim[RLIMIT_CORE].rlim_cur)
130 dump.u_dsize = 0;
131 #endif
132
133 /* Make sure we have enough room to write the stack and data areas. */
134 #ifdef __sparc__
135 if ((dump.u_ssize) >
136 current->rlim[RLIMIT_CORE].rlim_cur)
137 dump.u_ssize = 0;
138 #else
139 if ((dump.u_ssize+1) * PAGE_SIZE >
140 current->rlim[RLIMIT_CORE].rlim_cur)
141 dump.u_ssize = 0;
142 #endif
143
144 /* make sure we actually have a data and stack area to dump */
145 set_fs(USER_DS);
146 #ifdef __sparc__
147 if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
148 dump.u_dsize = 0;
149 if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
150 dump.u_ssize = 0;
151 #else
152 if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
153 dump.u_dsize = 0;
154 if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
155 dump.u_ssize = 0;
156 #endif
157
158 set_fs(KERNEL_DS);
159 /* struct user */
160 DUMP_WRITE(&dump,sizeof(dump));
161 /* Now dump all of the user data. Include malloced stuff as well */
162 #ifndef __sparc__
163 DUMP_SEEK(PAGE_SIZE);
164 #endif
165 /* now we start writing out the user space info */
166 set_fs(USER_DS);
167 /* Dump the data area */
168 if (dump.u_dsize != 0) {
169 dump_start = START_DATA(dump);
170 #ifdef __sparc__
171 dump_size = dump.u_dsize;
172 #else
173 dump_size = dump.u_dsize << PAGE_SHIFT;
174 #endif
175 DUMP_WRITE(dump_start,dump_size);
176 }
177 /* Now prepare to dump the stack area */
178 if (dump.u_ssize != 0) {
179 dump_start = START_STACK(dump);
180 #ifdef __sparc__
181 dump_size = dump.u_ssize;
182 #else
183 dump_size = dump.u_ssize << PAGE_SHIFT;
184 #endif
185 DUMP_WRITE(dump_start,dump_size);
186 }
187 /* Finally dump the task struct. Not be used by gdb, but could be useful */
188 set_fs(KERNEL_DS);
189 DUMP_WRITE(current,sizeof(*current));
190 end_coredump:
191 set_fs(fs);
192 return has_dumped;
193 }
194
195 /*
196 * create_aout_tables() parses the env- and arg-strings in new user
197 * memory and creates the pointer tables from them, and puts their
198 * addresses on the "stack", returning the new stack pointer value.
199 */
create_aout_tables(char * p,struct linux_binprm * bprm)200 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
201 {
202 char **argv, **envp;
203 unsigned long * sp;
204 int argc = bprm->argc;
205 int envc = bprm->envc;
206
207 sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
208 #ifdef __sparc__
209 /* This imposes the proper stack alignment for a new process. */
210 sp = (unsigned long *) (((unsigned long) sp) & ~7);
211 if ((envc+argc+3)&1) --sp;
212 #endif
213 #ifdef __alpha__
214 /* whee.. test-programs are so much fun. */
215 put_user(0, --sp);
216 put_user(0, --sp);
217 if (bprm->loader) {
218 put_user(0, --sp);
219 put_user(0x3eb, --sp);
220 put_user(bprm->loader, --sp);
221 put_user(0x3ea, --sp);
222 }
223 put_user(bprm->exec, --sp);
224 put_user(0x3e9, --sp);
225 #endif
226 sp -= envc+1;
227 envp = (char **) sp;
228 sp -= argc+1;
229 argv = (char **) sp;
230 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
231 put_user((unsigned long) envp,--sp);
232 put_user((unsigned long) argv,--sp);
233 #endif
234 put_user(argc,--sp);
235 current->mm->arg_start = (unsigned long) p;
236 while (argc-->0) {
237 char c;
238 put_user(p,argv++);
239 do {
240 get_user(c,p++);
241 } while (c);
242 }
243 put_user(NULL,argv);
244 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
245 while (envc-->0) {
246 char c;
247 put_user(p,envp++);
248 do {
249 get_user(c,p++);
250 } while (c);
251 }
252 put_user(NULL,envp);
253 current->mm->env_end = (unsigned long) p;
254 return sp;
255 }
256
257 /*
258 * These are the functions used to load a.out style executables and shared
259 * libraries. There is no binary dependent code anywhere else.
260 */
261
load_aout_binary(struct linux_binprm * bprm,struct pt_regs * regs)262 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
263 {
264 struct exec ex;
265 unsigned long error;
266 unsigned long fd_offset;
267 unsigned long rlim;
268 int retval;
269
270 ex = *((struct exec *) bprm->buf); /* exec-header */
271 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
272 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
273 N_TRSIZE(ex) || N_DRSIZE(ex) ||
274 bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
275 return -ENOEXEC;
276 }
277
278 fd_offset = N_TXTOFF(ex);
279
280 /* Check initial limits. This avoids letting people circumvent
281 * size limits imposed on them by creating programs with large
282 * arrays in the data or bss.
283 */
284 rlim = current->rlim[RLIMIT_DATA].rlim_cur;
285 if (rlim >= RLIM_INFINITY)
286 rlim = ~0;
287 if (ex.a_data + ex.a_bss > rlim)
288 return -ENOMEM;
289
290 /* Flush all traces of the currently running executable */
291 retval = flush_old_exec(bprm);
292 if (retval)
293 return retval;
294
295 /* OK, This is the point of no return */
296 #if defined(__alpha__)
297 SET_AOUT_PERSONALITY(bprm, ex);
298 #elif defined(__sparc__)
299 set_personality(PER_SUNOS);
300 #if !defined(__sparc_v9__)
301 memcpy(¤t->thread.core_exec, &ex, sizeof(struct exec));
302 #endif
303 #else
304 set_personality(PER_LINUX);
305 #endif
306
307 current->mm->end_code = ex.a_text +
308 (current->mm->start_code = N_TXTADDR(ex));
309 current->mm->end_data = ex.a_data +
310 (current->mm->start_data = N_DATADDR(ex));
311 current->mm->brk = ex.a_bss +
312 (current->mm->start_brk = N_BSSADDR(ex));
313
314 current->mm->rss = 0;
315 current->mm->mmap = NULL;
316 compute_creds(bprm);
317 current->flags &= ~PF_FORKNOEXEC;
318 #ifdef __sparc__
319 if (N_MAGIC(ex) == NMAGIC) {
320 loff_t pos = fd_offset;
321 /* Fuck me plenty... */
322 /* <AOL></AOL> */
323 down_write(¤t->mm->mmap_sem);
324 error = do_brk(N_TXTADDR(ex), ex.a_text);
325 up_write(¤t->mm->mmap_sem);
326 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
327 ex.a_text, &pos);
328 down_write(¤t->mm->mmap_sem);
329 error = do_brk(N_DATADDR(ex), ex.a_data);
330 up_write(¤t->mm->mmap_sem);
331 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
332 ex.a_data, &pos);
333 goto beyond_if;
334 }
335 #endif
336
337 if (N_MAGIC(ex) == OMAGIC) {
338 unsigned long text_addr, map_size;
339 loff_t pos;
340
341 text_addr = N_TXTADDR(ex);
342
343 #if defined(__alpha__) || defined(__sparc__)
344 pos = fd_offset;
345 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
346 #else
347 pos = 32;
348 map_size = ex.a_text+ex.a_data;
349 #endif
350 down_write(¤t->mm->mmap_sem);
351 error = do_brk(text_addr & PAGE_MASK, map_size);
352 up_write(¤t->mm->mmap_sem);
353 if (error != (text_addr & PAGE_MASK)) {
354 send_sig(SIGKILL, current, 0);
355 return error;
356 }
357
358 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
359 ex.a_text+ex.a_data, &pos);
360 if ((signed long)error < 0) {
361 send_sig(SIGKILL, current, 0);
362 return error;
363 }
364
365 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
366 } else {
367 static unsigned long error_time, error_time2;
368 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
369 (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
370 {
371 printk(KERN_NOTICE "executable not page aligned\n");
372 error_time2 = jiffies;
373 }
374
375 if ((fd_offset & ~PAGE_MASK) != 0 &&
376 (jiffies-error_time) > 5*HZ)
377 {
378 printk(KERN_WARNING
379 "fd_offset is not page aligned. Please convert program: %s\n",
380 bprm->file->f_dentry->d_name.name);
381 error_time = jiffies;
382 }
383
384 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
385 loff_t pos = fd_offset;
386 down_write(¤t->mm->mmap_sem);
387 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
388 up_write(¤t->mm->mmap_sem);
389 bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
390 ex.a_text+ex.a_data, &pos);
391 flush_icache_range((unsigned long) N_TXTADDR(ex),
392 (unsigned long) N_TXTADDR(ex) +
393 ex.a_text+ex.a_data);
394 goto beyond_if;
395 }
396
397 down_write(¤t->mm->mmap_sem);
398 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
399 PROT_READ | PROT_EXEC,
400 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
401 fd_offset);
402 up_write(¤t->mm->mmap_sem);
403
404 if (error != N_TXTADDR(ex)) {
405 send_sig(SIGKILL, current, 0);
406 return error;
407 }
408
409 down_write(¤t->mm->mmap_sem);
410 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
411 PROT_READ | PROT_WRITE | PROT_EXEC,
412 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
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 retval = set_brk(current->mm->start_brk, current->mm->brk);
424 if (retval < 0) {
425 send_sig(SIGKILL, current, 0);
426 return retval;
427 }
428
429 retval = setup_arg_pages(bprm);
430 if (retval < 0) {
431 /* Someone check-me: is this error path enough? */
432 send_sig(SIGKILL, current, 0);
433 return retval;
434 }
435
436 current->mm->start_stack =
437 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
438 #ifdef __alpha__
439 regs->gp = ex.a_gpvalue;
440 #endif
441 start_thread(regs, ex.a_entry, current->mm->start_stack);
442 if (current->ptrace & PT_PTRACED)
443 send_sig(SIGTRAP, current, 0);
444 return 0;
445 }
446
load_aout_library(struct file * file)447 static int load_aout_library(struct file *file)
448 {
449 struct inode * inode;
450 unsigned long bss, start_addr, len;
451 unsigned long error;
452 int retval;
453 struct exec ex;
454
455 inode = file->f_dentry->d_inode;
456
457 retval = -ENOEXEC;
458 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
459 if (error != sizeof(ex))
460 goto out;
461
462 /* We come in here for the regular a.out style of shared libraries */
463 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
464 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
465 inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
466 goto out;
467 }
468
469 if (N_FLAGS(ex))
470 goto out;
471
472 /* For QMAGIC, the starting address is 0x20 into the page. We mask
473 this off to get the starting address for the page */
474
475 start_addr = ex.a_entry & 0xfffff000;
476
477 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
478 static unsigned long error_time;
479 loff_t pos = N_TXTOFF(ex);
480
481 if ((jiffies-error_time) > 5*HZ)
482 {
483 printk(KERN_WARNING
484 "N_TXTOFF is not page aligned. Please convert library: %s\n",
485 file->f_dentry->d_name.name);
486 error_time = jiffies;
487 }
488
489 down_write(¤t->mm->mmap_sem);
490 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
491 up_write(¤t->mm->mmap_sem);
492
493 file->f_op->read(file, (char *)start_addr,
494 ex.a_text + ex.a_data, &pos);
495 flush_icache_range((unsigned long) start_addr,
496 (unsigned long) start_addr + ex.a_text + ex.a_data);
497
498 retval = 0;
499 goto out;
500 }
501 /* Now use mmap to map the library into memory. */
502 down_write(¤t->mm->mmap_sem);
503 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
504 PROT_READ | PROT_WRITE | PROT_EXEC,
505 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
506 N_TXTOFF(ex));
507 up_write(¤t->mm->mmap_sem);
508 retval = error;
509 if (error != start_addr)
510 goto out;
511
512 len = PAGE_ALIGN(ex.a_text + ex.a_data);
513 bss = ex.a_text + ex.a_data + ex.a_bss;
514 if (bss > len) {
515 down_write(¤t->mm->mmap_sem);
516 error = do_brk(start_addr + len, bss - len);
517 up_write(¤t->mm->mmap_sem);
518
519 retval = error;
520 if (error != start_addr + len)
521 goto out;
522 }
523 retval = 0;
524 out:
525 return retval;
526 }
527
init_aout_binfmt(void)528 static int __init init_aout_binfmt(void)
529 {
530 return register_binfmt(&aout_format);
531 }
532
exit_aout_binfmt(void)533 static void __exit exit_aout_binfmt(void)
534 {
535 unregister_binfmt(&aout_format);
536 }
537
538 EXPORT_NO_SYMBOLS;
539
540 module_init(init_aout_binfmt);
541 module_exit(exit_aout_binfmt);
542 MODULE_LICENSE("GPL");
543