blob: 346b69405363b7419d7d4b591b240074d72bff6b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/time.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/cacheflush.h>
David Howells7fa30312008-02-08 04:19:28 -080031#include <asm/a.out-core.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
34static int load_aout_library(struct file*);
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080035static int aout_core_dump(struct coredump_params *cprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Linus Torvalds1da177e2005-04-16 15:20:36 -070037static struct linux_binfmt aout_format = {
38 .module = THIS_MODULE,
39 .load_binary = load_aout_binary,
40 .load_shlib = load_aout_library,
41 .core_dump = aout_core_dump,
42 .min_coredump = PAGE_SIZE
43};
44
45#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
46
47static int set_brk(unsigned long start, unsigned long end)
48{
49 start = PAGE_ALIGN(start);
50 end = PAGE_ALIGN(end);
51 if (end > start) {
52 unsigned long addr;
53 down_write(&current->mm->mmap_sem);
54 addr = do_brk(start, end - start);
55 up_write(&current->mm->mmap_sem);
56 if (BAD_ADDR(addr))
57 return addr;
58 }
59 return 0;
60}
61
62/*
63 * These are the only things you should do on a core-file: use only these
64 * macros to write out all the necessary info.
65 */
66
67static int dump_write(struct file *file, const void *addr, int nr)
68{
69 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
70}
71
72#define DUMP_WRITE(addr, nr) \
73 if (!dump_write(file, (void *)(addr), (nr))) \
74 goto end_coredump;
75
76#define DUMP_SEEK(offset) \
77if (file->f_op->llseek) { \
78 if (file->f_op->llseek(file,(offset),0) != (offset)) \
79 goto end_coredump; \
80} else file->f_pos = (offset)
81
82/*
83 * Routine writes a core dump image in the current directory.
84 * Currently only a stub-function.
85 *
86 * Note that setuid/setgid files won't make a core-dump if the uid/gid
87 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
88 * field, which also makes sure the core-dumps won't be recursive if the
89 * dumping of the process results in another error..
90 */
91
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080092static int aout_core_dump(struct coredump_params *cprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080094 struct file *file = cprm->file;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 mm_segment_t fs;
96 int has_dumped = 0;
97 unsigned long dump_start, dump_size;
98 struct user dump;
Al Viro17580d72009-01-03 07:16:23 +000099#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100# define START_DATA(u) (u.start_data)
Al Viro17580d72009-01-03 07:16:23 +0000101#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102# define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104# define START_STACK(u) (u.start_stack)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106 fs = get_fs();
107 set_fs(KERNEL_DS);
108 has_dumped = 1;
109 current->flags |= PF_DUMPCORE;
110 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
H. Peter Anvin6e16d892008-02-07 00:15:57 -0800111 dump.u_ar0 = offsetof(struct user, regs);
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800112 dump.signal = cprm->signr;
113 aout_dump_thread(cprm->regs, &dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
115/* If the size of the dump file exceeds the rlimit, then see what would happen
116 if we wrote the stack, but not the data area. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800117 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 dump.u_dsize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120/* Make sure we have enough room to write the stack and data areas. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800121 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
124/* make sure we actually have a data and stack area to dump */
125 set_fs(USER_DS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
127 dump.u_dsize = 0;
128 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
129 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
131 set_fs(KERNEL_DS);
132/* struct user */
133 DUMP_WRITE(&dump,sizeof(dump));
134/* Now dump all of the user data. Include malloced stuff as well */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 DUMP_SEEK(PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136/* now we start writing out the user space info */
137 set_fs(USER_DS);
138/* Dump the data area */
139 if (dump.u_dsize != 0) {
140 dump_start = START_DATA(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 dump_size = dump.u_dsize << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 DUMP_WRITE(dump_start,dump_size);
143 }
144/* Now prepare to dump the stack area */
145 if (dump.u_ssize != 0) {
146 dump_start = START_STACK(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 dump_size = dump.u_ssize << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 DUMP_WRITE(dump_start,dump_size);
149 }
150/* Finally dump the task struct. Not be used by gdb, but could be useful */
151 set_fs(KERNEL_DS);
152 DUMP_WRITE(current,sizeof(*current));
153end_coredump:
154 set_fs(fs);
155 return has_dumped;
156}
157
158/*
159 * create_aout_tables() parses the env- and arg-strings in new user
160 * memory and creates the pointer tables from them, and puts their
161 * addresses on the "stack", returning the new stack pointer value.
162 */
163static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
164{
165 char __user * __user *argv;
166 char __user * __user *envp;
167 unsigned long __user *sp;
168 int argc = bprm->argc;
169 int envc = bprm->envc;
170
171 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172#ifdef __alpha__
173/* whee.. test-programs are so much fun. */
174 put_user(0, --sp);
175 put_user(0, --sp);
176 if (bprm->loader) {
177 put_user(0, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000178 put_user(1003, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 put_user(bprm->loader, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000180 put_user(1002, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 }
182 put_user(bprm->exec, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000183 put_user(1001, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184#endif
185 sp -= envc+1;
186 envp = (char __user * __user *) sp;
187 sp -= argc+1;
188 argv = (char __user * __user *) sp;
Al Viro17580d72009-01-03 07:16:23 +0000189#ifndef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 put_user((unsigned long) envp,--sp);
191 put_user((unsigned long) argv,--sp);
192#endif
193 put_user(argc,--sp);
194 current->mm->arg_start = (unsigned long) p;
195 while (argc-->0) {
196 char c;
197 put_user(p,argv++);
198 do {
199 get_user(c,p++);
200 } while (c);
201 }
202 put_user(NULL,argv);
203 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
204 while (envc-->0) {
205 char c;
206 put_user(p,envp++);
207 do {
208 get_user(c,p++);
209 } while (c);
210 }
211 put_user(NULL,envp);
212 current->mm->env_end = (unsigned long) p;
213 return sp;
214}
215
216/*
217 * These are the functions used to load a.out style executables and shared
218 * libraries. There is no binary dependent code anywhere else.
219 */
220
221static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
222{
223 struct exec ex;
224 unsigned long error;
225 unsigned long fd_offset;
226 unsigned long rlim;
227 int retval;
228
229 ex = *((struct exec *) bprm->buf); /* exec-header */
230 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
231 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
232 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800233 i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 return -ENOEXEC;
235 }
236
Eugene Teo8454aee2006-09-29 01:59:33 -0700237 /*
238 * Requires a mmap handler. This prevents people from using a.out
239 * as part of an exploit attack against /proc-related vulnerabilities.
240 */
241 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
242 return -ENOEXEC;
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 fd_offset = N_TXTOFF(ex);
245
246 /* Check initial limits. This avoids letting people circumvent
247 * size limits imposed on them by creating programs with large
248 * arrays in the data or bss.
249 */
250 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
251 if (rlim >= RLIM_INFINITY)
252 rlim = ~0;
253 if (ex.a_data + ex.a_bss > rlim)
254 return -ENOMEM;
255
256 /* Flush all traces of the currently running executable */
257 retval = flush_old_exec(bprm);
258 if (retval)
259 return retval;
260
261 /* OK, This is the point of no return */
Al Viro17580d72009-01-03 07:16:23 +0000262#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 SET_AOUT_PERSONALITY(bprm, ex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264#else
265 set_personality(PER_LINUX);
266#endif
267
268 current->mm->end_code = ex.a_text +
269 (current->mm->start_code = N_TXTADDR(ex));
270 current->mm->end_data = ex.a_data +
271 (current->mm->start_data = N_DATADDR(ex));
272 current->mm->brk = ex.a_bss +
273 (current->mm->start_brk = N_BSSADDR(ex));
274 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700275 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
David Howellsa6f76f22008-11-14 10:39:24 +1100277 install_exec_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 current->flags &= ~PF_FORKNOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280 if (N_MAGIC(ex) == OMAGIC) {
281 unsigned long text_addr, map_size;
282 loff_t pos;
283
284 text_addr = N_TXTADDR(ex);
285
Al Virofe30af92009-01-03 07:16:13 +0000286#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 pos = fd_offset;
288 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
289#else
290 pos = 32;
291 map_size = ex.a_text+ex.a_data;
292#endif
293 down_write(&current->mm->mmap_sem);
294 error = do_brk(text_addr & PAGE_MASK, map_size);
295 up_write(&current->mm->mmap_sem);
296 if (error != (text_addr & PAGE_MASK)) {
297 send_sig(SIGKILL, current, 0);
298 return error;
299 }
300
301 error = bprm->file->f_op->read(bprm->file,
302 (char __user *)text_addr,
303 ex.a_text+ex.a_data, &pos);
304 if ((signed long)error < 0) {
305 send_sig(SIGKILL, current, 0);
306 return error;
307 }
308
309 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
310 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700312 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 {
314 printk(KERN_NOTICE "executable not page aligned\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 }
316
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700317 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 {
319 printk(KERN_WARNING
320 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800321 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 }
323
324 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
325 loff_t pos = fd_offset;
326 down_write(&current->mm->mmap_sem);
327 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
328 up_write(&current->mm->mmap_sem);
329 bprm->file->f_op->read(bprm->file,
330 (char __user *)N_TXTADDR(ex),
331 ex.a_text+ex.a_data, &pos);
332 flush_icache_range((unsigned long) N_TXTADDR(ex),
333 (unsigned long) N_TXTADDR(ex) +
334 ex.a_text+ex.a_data);
335 goto beyond_if;
336 }
337
338 down_write(&current->mm->mmap_sem);
339 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
340 PROT_READ | PROT_EXEC,
341 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
342 fd_offset);
343 up_write(&current->mm->mmap_sem);
344
345 if (error != N_TXTADDR(ex)) {
346 send_sig(SIGKILL, current, 0);
347 return error;
348 }
349
350 down_write(&current->mm->mmap_sem);
351 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
352 PROT_READ | PROT_WRITE | PROT_EXEC,
353 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
354 fd_offset + ex.a_text);
355 up_write(&current->mm->mmap_sem);
356 if (error != N_DATADDR(ex)) {
357 send_sig(SIGKILL, current, 0);
358 return error;
359 }
360 }
361beyond_if:
362 set_binfmt(&aout_format);
363
364 retval = set_brk(current->mm->start_brk, current->mm->brk);
365 if (retval < 0) {
366 send_sig(SIGKILL, current, 0);
367 return retval;
368 }
369
370 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
371 if (retval < 0) {
372 /* Someone check-me: is this error path enough? */
373 send_sig(SIGKILL, current, 0);
374 return retval;
375 }
376
377 current->mm->start_stack =
378 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
379#ifdef __alpha__
380 regs->gp = ex.a_gpvalue;
381#endif
382 start_thread(regs, ex.a_entry, current->mm->start_stack);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 return 0;
384}
385
386static int load_aout_library(struct file *file)
387{
388 struct inode * inode;
389 unsigned long bss, start_addr, len;
390 unsigned long error;
391 int retval;
392 struct exec ex;
393
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800394 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395
396 retval = -ENOEXEC;
397 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
398 if (error != sizeof(ex))
399 goto out;
400
401 /* We come in here for the regular a.out style of shared libraries */
402 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
403 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
404 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
405 goto out;
406 }
407
Eugene Teo8454aee2006-09-29 01:59:33 -0700408 /*
409 * Requires a mmap handler. This prevents people from using a.out
410 * as part of an exploit attack against /proc-related vulnerabilities.
411 */
412 if (!file->f_op || !file->f_op->mmap)
413 goto out;
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 if (N_FLAGS(ex))
416 goto out;
417
418 /* For QMAGIC, the starting address is 0x20 into the page. We mask
419 this off to get the starting address for the page */
420
421 start_addr = ex.a_entry & 0xfffff000;
422
423 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 loff_t pos = N_TXTOFF(ex);
425
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700426 if (printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 {
428 printk(KERN_WARNING
429 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800430 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 }
432 down_write(&current->mm->mmap_sem);
433 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
434 up_write(&current->mm->mmap_sem);
435
436 file->f_op->read(file, (char __user *)start_addr,
437 ex.a_text + ex.a_data, &pos);
438 flush_icache_range((unsigned long) start_addr,
439 (unsigned long) start_addr + ex.a_text + ex.a_data);
440
441 retval = 0;
442 goto out;
443 }
444 /* Now use mmap to map the library into memory. */
445 down_write(&current->mm->mmap_sem);
446 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
447 PROT_READ | PROT_WRITE | PROT_EXEC,
448 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
449 N_TXTOFF(ex));
450 up_write(&current->mm->mmap_sem);
451 retval = error;
452 if (error != start_addr)
453 goto out;
454
455 len = PAGE_ALIGN(ex.a_text + ex.a_data);
456 bss = ex.a_text + ex.a_data + ex.a_bss;
457 if (bss > len) {
458 down_write(&current->mm->mmap_sem);
459 error = do_brk(start_addr + len, bss - len);
460 up_write(&current->mm->mmap_sem);
461 retval = error;
462 if (error != start_addr + len)
463 goto out;
464 }
465 retval = 0;
466out:
467 return retval;
468}
469
470static int __init init_aout_binfmt(void)
471{
472 return register_binfmt(&aout_format);
473}
474
475static void __exit exit_aout_binfmt(void)
476{
477 unregister_binfmt(&aout_format);
478}
479
480core_initcall(init_aout_binfmt);
481module_exit(exit_aout_binfmt);
482MODULE_LICENSE("GPL");