blob: a6395bdb26aeb13b7b98c74df4f77780c1c95412 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/binfmts.h>
24#include <linux/personality.h>
25#include <linux/init.h>
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -080026#include <linux/coredump.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29#include <asm/system.h>
30#include <asm/uaccess.h>
31#include <asm/cacheflush.h>
David Howells7fa30312008-02-08 04:19:28 -080032#include <asm/a.out-core.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
35static int load_aout_library(struct file*);
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080036static int aout_core_dump(struct coredump_params *cprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static struct linux_binfmt aout_format = {
39 .module = THIS_MODULE,
40 .load_binary = load_aout_binary,
41 .load_shlib = load_aout_library,
42 .core_dump = aout_core_dump,
43 .min_coredump = PAGE_SIZE
44};
45
46#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
47
48static int set_brk(unsigned long start, unsigned long end)
49{
50 start = PAGE_ALIGN(start);
51 end = PAGE_ALIGN(end);
52 if (end > start) {
53 unsigned long addr;
54 down_write(&current->mm->mmap_sem);
55 addr = do_brk(start, end - start);
56 up_write(&current->mm->mmap_sem);
57 if (BAD_ADDR(addr))
58 return addr;
59 }
60 return 0;
61}
62
63/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 * Routine writes a core dump image in the current directory.
65 * Currently only a stub-function.
66 *
67 * Note that setuid/setgid files won't make a core-dump if the uid/gid
68 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
69 * field, which also makes sure the core-dumps won't be recursive if the
70 * dumping of the process results in another error..
71 */
72
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080073static int aout_core_dump(struct coredump_params *cprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080075 struct file *file = cprm->file;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 mm_segment_t fs;
77 int has_dumped = 0;
Borislav Petkov7731d9a2010-03-23 13:35:15 -070078 void __user *dump_start;
79 int dump_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 struct user dump;
Al Viro17580d72009-01-03 07:16:23 +000081#ifdef __alpha__
Borislav Petkov7731d9a2010-03-23 13:35:15 -070082# define START_DATA(u) ((void __user *)u.start_data)
Al Viro17580d72009-01-03 07:16:23 +000083#else
Borislav Petkov7731d9a2010-03-23 13:35:15 -070084# define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \
85 u.start_code))
Linus Torvalds1da177e2005-04-16 15:20:36 -070086#endif
Borislav Petkov7731d9a2010-03-23 13:35:15 -070087# define START_STACK(u) ((void __user *)u.start_stack)
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89 fs = get_fs();
90 set_fs(KERNEL_DS);
91 has_dumped = 1;
92 current->flags |= PF_DUMPCORE;
93 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
H. Peter Anvin6e16d892008-02-07 00:15:57 -080094 dump.u_ar0 = offsetof(struct user, regs);
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080095 dump.signal = cprm->signr;
96 aout_dump_thread(cprm->regs, &dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98/* If the size of the dump file exceeds the rlimit, then see what would happen
99 if we wrote the stack, but not the data area. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800100 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 dump.u_dsize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
103/* Make sure we have enough room to write the stack and data areas. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800104 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107/* make sure we actually have a data and stack area to dump */
108 set_fs(USER_DS);
Borislav Petkov7731d9a2010-03-23 13:35:15 -0700109 if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 dump.u_dsize = 0;
Borislav Petkov7731d9a2010-03-23 13:35:15 -0700111 if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 set_fs(KERNEL_DS);
115/* struct user */
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800116 if (!dump_write(file, &dump, sizeof(dump)))
117 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118/* Now dump all of the user data. Include malloced stuff as well */
Daisuke HATAYAMA05f47fd2010-03-05 13:44:05 -0800119 if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
120 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121/* now we start writing out the user space info */
122 set_fs(USER_DS);
123/* Dump the data area */
124 if (dump.u_dsize != 0) {
125 dump_start = START_DATA(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 dump_size = dump.u_dsize << PAGE_SHIFT;
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800127 if (!dump_write(file, dump_start, dump_size))
128 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 }
130/* Now prepare to dump the stack area */
131 if (dump.u_ssize != 0) {
132 dump_start = START_STACK(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 dump_size = dump.u_ssize << PAGE_SHIFT;
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800134 if (!dump_write(file, dump_start, dump_size))
135 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137end_coredump:
138 set_fs(fs);
139 return has_dumped;
140}
141
142/*
143 * create_aout_tables() parses the env- and arg-strings in new user
144 * memory and creates the pointer tables from them, and puts their
145 * addresses on the "stack", returning the new stack pointer value.
146 */
147static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
148{
149 char __user * __user *argv;
150 char __user * __user *envp;
151 unsigned long __user *sp;
152 int argc = bprm->argc;
153 int envc = bprm->envc;
154
155 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156#ifdef __alpha__
157/* whee.. test-programs are so much fun. */
158 put_user(0, --sp);
159 put_user(0, --sp);
160 if (bprm->loader) {
161 put_user(0, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000162 put_user(1003, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 put_user(bprm->loader, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000164 put_user(1002, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 }
166 put_user(bprm->exec, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000167 put_user(1001, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168#endif
169 sp -= envc+1;
170 envp = (char __user * __user *) sp;
171 sp -= argc+1;
172 argv = (char __user * __user *) sp;
Al Viro17580d72009-01-03 07:16:23 +0000173#ifndef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 put_user((unsigned long) envp,--sp);
175 put_user((unsigned long) argv,--sp);
176#endif
177 put_user(argc,--sp);
178 current->mm->arg_start = (unsigned long) p;
179 while (argc-->0) {
180 char c;
181 put_user(p,argv++);
182 do {
183 get_user(c,p++);
184 } while (c);
185 }
186 put_user(NULL,argv);
187 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
188 while (envc-->0) {
189 char c;
190 put_user(p,envp++);
191 do {
192 get_user(c,p++);
193 } while (c);
194 }
195 put_user(NULL,envp);
196 current->mm->env_end = (unsigned long) p;
197 return sp;
198}
199
200/*
201 * These are the functions used to load a.out style executables and shared
202 * libraries. There is no binary dependent code anywhere else.
203 */
204
205static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
206{
207 struct exec ex;
208 unsigned long error;
209 unsigned long fd_offset;
210 unsigned long rlim;
211 int retval;
212
213 ex = *((struct exec *) bprm->buf); /* exec-header */
214 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
215 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
216 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800217 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 -0700218 return -ENOEXEC;
219 }
220
Eugene Teo8454aee2006-09-29 01:59:33 -0700221 /*
222 * Requires a mmap handler. This prevents people from using a.out
223 * as part of an exploit attack against /proc-related vulnerabilities.
224 */
225 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
226 return -ENOEXEC;
227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 fd_offset = N_TXTOFF(ex);
229
230 /* Check initial limits. This avoids letting people circumvent
231 * size limits imposed on them by creating programs with large
232 * arrays in the data or bss.
233 */
Jiri Slabyd554ed892010-03-05 13:42:42 -0800234 rlim = rlimit(RLIMIT_DATA);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 if (rlim >= RLIM_INFINITY)
236 rlim = ~0;
237 if (ex.a_data + ex.a_bss > rlim)
238 return -ENOMEM;
239
240 /* Flush all traces of the currently running executable */
241 retval = flush_old_exec(bprm);
242 if (retval)
243 return retval;
244
245 /* OK, This is the point of no return */
Al Viro17580d72009-01-03 07:16:23 +0000246#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 SET_AOUT_PERSONALITY(bprm, ex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248#else
249 set_personality(PER_LINUX);
250#endif
Linus Torvalds221af7f2010-01-28 22:14:42 -0800251 setup_new_exec(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 current->mm->end_code = ex.a_text +
254 (current->mm->start_code = N_TXTADDR(ex));
255 current->mm->end_data = ex.a_data +
256 (current->mm->start_data = N_DATADDR(ex));
257 current->mm->brk = ex.a_bss +
258 (current->mm->start_brk = N_BSSADDR(ex));
259 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700260 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
David Howellsa6f76f22008-11-14 10:39:24 +1100262 install_exec_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 current->flags &= ~PF_FORKNOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265 if (N_MAGIC(ex) == OMAGIC) {
266 unsigned long text_addr, map_size;
267 loff_t pos;
268
269 text_addr = N_TXTADDR(ex);
270
Al Virofe30af92009-01-03 07:16:13 +0000271#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 pos = fd_offset;
273 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
274#else
275 pos = 32;
276 map_size = ex.a_text+ex.a_data;
277#endif
278 down_write(&current->mm->mmap_sem);
279 error = do_brk(text_addr & PAGE_MASK, map_size);
280 up_write(&current->mm->mmap_sem);
281 if (error != (text_addr & PAGE_MASK)) {
282 send_sig(SIGKILL, current, 0);
283 return error;
284 }
285
286 error = bprm->file->f_op->read(bprm->file,
287 (char __user *)text_addr,
288 ex.a_text+ex.a_data, &pos);
289 if ((signed long)error < 0) {
290 send_sig(SIGKILL, current, 0);
291 return error;
292 }
293
294 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
295 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700297 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 {
299 printk(KERN_NOTICE "executable not page aligned\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 }
301
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700302 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 {
304 printk(KERN_WARNING
305 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800306 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 }
308
309 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
310 loff_t pos = fd_offset;
311 down_write(&current->mm->mmap_sem);
312 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
313 up_write(&current->mm->mmap_sem);
314 bprm->file->f_op->read(bprm->file,
315 (char __user *)N_TXTADDR(ex),
316 ex.a_text+ex.a_data, &pos);
317 flush_icache_range((unsigned long) N_TXTADDR(ex),
318 (unsigned long) N_TXTADDR(ex) +
319 ex.a_text+ex.a_data);
320 goto beyond_if;
321 }
322
323 down_write(&current->mm->mmap_sem);
324 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
325 PROT_READ | PROT_EXEC,
326 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
327 fd_offset);
328 up_write(&current->mm->mmap_sem);
329
330 if (error != N_TXTADDR(ex)) {
331 send_sig(SIGKILL, current, 0);
332 return error;
333 }
334
335 down_write(&current->mm->mmap_sem);
336 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
337 PROT_READ | PROT_WRITE | PROT_EXEC,
338 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
339 fd_offset + ex.a_text);
340 up_write(&current->mm->mmap_sem);
341 if (error != N_DATADDR(ex)) {
342 send_sig(SIGKILL, current, 0);
343 return error;
344 }
345 }
346beyond_if:
347 set_binfmt(&aout_format);
348
349 retval = set_brk(current->mm->start_brk, current->mm->brk);
350 if (retval < 0) {
351 send_sig(SIGKILL, current, 0);
352 return retval;
353 }
354
355 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
356 if (retval < 0) {
357 /* Someone check-me: is this error path enough? */
358 send_sig(SIGKILL, current, 0);
359 return retval;
360 }
361
362 current->mm->start_stack =
363 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
364#ifdef __alpha__
365 regs->gp = ex.a_gpvalue;
366#endif
367 start_thread(regs, ex.a_entry, current->mm->start_stack);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 return 0;
369}
370
371static int load_aout_library(struct file *file)
372{
373 struct inode * inode;
374 unsigned long bss, start_addr, len;
375 unsigned long error;
376 int retval;
377 struct exec ex;
378
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800379 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
381 retval = -ENOEXEC;
382 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
383 if (error != sizeof(ex))
384 goto out;
385
386 /* We come in here for the regular a.out style of shared libraries */
387 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
388 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
389 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
390 goto out;
391 }
392
Eugene Teo8454aee2006-09-29 01:59:33 -0700393 /*
394 * Requires a mmap handler. This prevents people from using a.out
395 * as part of an exploit attack against /proc-related vulnerabilities.
396 */
397 if (!file->f_op || !file->f_op->mmap)
398 goto out;
399
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 if (N_FLAGS(ex))
401 goto out;
402
403 /* For QMAGIC, the starting address is 0x20 into the page. We mask
404 this off to get the starting address for the page */
405
406 start_addr = ex.a_entry & 0xfffff000;
407
408 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 loff_t pos = N_TXTOFF(ex);
410
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700411 if (printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 {
413 printk(KERN_WARNING
414 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800415 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 }
417 down_write(&current->mm->mmap_sem);
418 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
419 up_write(&current->mm->mmap_sem);
420
421 file->f_op->read(file, (char __user *)start_addr,
422 ex.a_text + ex.a_data, &pos);
423 flush_icache_range((unsigned long) start_addr,
424 (unsigned long) start_addr + ex.a_text + ex.a_data);
425
426 retval = 0;
427 goto out;
428 }
429 /* Now use mmap to map the library into memory. */
430 down_write(&current->mm->mmap_sem);
431 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
432 PROT_READ | PROT_WRITE | PROT_EXEC,
433 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
434 N_TXTOFF(ex));
435 up_write(&current->mm->mmap_sem);
436 retval = error;
437 if (error != start_addr)
438 goto out;
439
440 len = PAGE_ALIGN(ex.a_text + ex.a_data);
441 bss = ex.a_text + ex.a_data + ex.a_bss;
442 if (bss > len) {
443 down_write(&current->mm->mmap_sem);
444 error = do_brk(start_addr + len, bss - len);
445 up_write(&current->mm->mmap_sem);
446 retval = error;
447 if (error != start_addr + len)
448 goto out;
449 }
450 retval = 0;
451out:
452 return retval;
453}
454
455static int __init init_aout_binfmt(void)
456{
457 return register_binfmt(&aout_format);
458}
459
460static void __exit exit_aout_binfmt(void)
461{
462 unregister_binfmt(&aout_format);
463}
464
465core_initcall(init_aout_binfmt);
466module_exit(exit_aout_binfmt);
467MODULE_LICENSE("GPL");