blob: 15d80bb35d6f7c9e10adcb7ac62d587813449870 [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>
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -080027#include <linux/coredump.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;
78 unsigned long dump_start, dump_size;
79 struct user dump;
Al Viro17580d72009-01-03 07:16:23 +000080#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -070081# define START_DATA(u) (u.start_data)
Al Viro17580d72009-01-03 07:16:23 +000082#else
Linus Torvalds1da177e2005-04-16 15:20:36 -070083# define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070085# define START_STACK(u) (u.start_stack)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87 fs = get_fs();
88 set_fs(KERNEL_DS);
89 has_dumped = 1;
90 current->flags |= PF_DUMPCORE;
91 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
H. Peter Anvin6e16d892008-02-07 00:15:57 -080092 dump.u_ar0 = offsetof(struct user, regs);
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080093 dump.signal = cprm->signr;
94 aout_dump_thread(cprm->regs, &dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96/* If the size of the dump file exceeds the rlimit, then see what would happen
97 if we wrote the stack, but not the data area. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -080098 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 dump.u_dsize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
101/* Make sure we have enough room to write the stack and data areas. */
Masami Hiramatsuf6151df2009-12-17 15:27:16 -0800102 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104
105/* make sure we actually have a data and stack area to dump */
106 set_fs(USER_DS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
108 dump.u_dsize = 0;
109 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
110 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112 set_fs(KERNEL_DS);
113/* struct user */
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800114 if (!dump_write(file, &dump, sizeof(dump)))
115 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116/* Now dump all of the user data. Include malloced stuff as well */
Daisuke HATAYAMA05f47fd2010-03-05 13:44:05 -0800117 if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
118 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119/* now we start writing out the user space info */
120 set_fs(USER_DS);
121/* Dump the data area */
122 if (dump.u_dsize != 0) {
123 dump_start = START_DATA(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 dump_size = dump.u_dsize << PAGE_SHIFT;
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800125 if (!dump_write(file, dump_start, dump_size))
126 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 }
128/* Now prepare to dump the stack area */
129 if (dump.u_ssize != 0) {
130 dump_start = START_STACK(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 dump_size = dump.u_ssize << PAGE_SHIFT;
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800132 if (!dump_write(file, dump_start, dump_size))
133 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 }
135/* Finally dump the task struct. Not be used by gdb, but could be useful */
136 set_fs(KERNEL_DS);
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800137 if (!dump_write(file, current, sizeof(*current)))
138 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139end_coredump:
140 set_fs(fs);
141 return has_dumped;
142}
143
144/*
145 * create_aout_tables() parses the env- and arg-strings in new user
146 * memory and creates the pointer tables from them, and puts their
147 * addresses on the "stack", returning the new stack pointer value.
148 */
149static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
150{
151 char __user * __user *argv;
152 char __user * __user *envp;
153 unsigned long __user *sp;
154 int argc = bprm->argc;
155 int envc = bprm->envc;
156
157 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158#ifdef __alpha__
159/* whee.. test-programs are so much fun. */
160 put_user(0, --sp);
161 put_user(0, --sp);
162 if (bprm->loader) {
163 put_user(0, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000164 put_user(1003, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 put_user(bprm->loader, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000166 put_user(1002, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 }
168 put_user(bprm->exec, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000169 put_user(1001, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170#endif
171 sp -= envc+1;
172 envp = (char __user * __user *) sp;
173 sp -= argc+1;
174 argv = (char __user * __user *) sp;
Al Viro17580d72009-01-03 07:16:23 +0000175#ifndef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 put_user((unsigned long) envp,--sp);
177 put_user((unsigned long) argv,--sp);
178#endif
179 put_user(argc,--sp);
180 current->mm->arg_start = (unsigned long) p;
181 while (argc-->0) {
182 char c;
183 put_user(p,argv++);
184 do {
185 get_user(c,p++);
186 } while (c);
187 }
188 put_user(NULL,argv);
189 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
190 while (envc-->0) {
191 char c;
192 put_user(p,envp++);
193 do {
194 get_user(c,p++);
195 } while (c);
196 }
197 put_user(NULL,envp);
198 current->mm->env_end = (unsigned long) p;
199 return sp;
200}
201
202/*
203 * These are the functions used to load a.out style executables and shared
204 * libraries. There is no binary dependent code anywhere else.
205 */
206
207static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
208{
209 struct exec ex;
210 unsigned long error;
211 unsigned long fd_offset;
212 unsigned long rlim;
213 int retval;
214
215 ex = *((struct exec *) bprm->buf); /* exec-header */
216 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
217 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
218 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800219 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 -0700220 return -ENOEXEC;
221 }
222
Eugene Teo8454aee2006-09-29 01:59:33 -0700223 /*
224 * Requires a mmap handler. This prevents people from using a.out
225 * as part of an exploit attack against /proc-related vulnerabilities.
226 */
227 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
228 return -ENOEXEC;
229
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 fd_offset = N_TXTOFF(ex);
231
232 /* Check initial limits. This avoids letting people circumvent
233 * size limits imposed on them by creating programs with large
234 * arrays in the data or bss.
235 */
Jiri Slabyd554ed892010-03-05 13:42:42 -0800236 rlim = rlimit(RLIMIT_DATA);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 if (rlim >= RLIM_INFINITY)
238 rlim = ~0;
239 if (ex.a_data + ex.a_bss > rlim)
240 return -ENOMEM;
241
242 /* Flush all traces of the currently running executable */
243 retval = flush_old_exec(bprm);
244 if (retval)
245 return retval;
246
247 /* OK, This is the point of no return */
Al Viro17580d72009-01-03 07:16:23 +0000248#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 SET_AOUT_PERSONALITY(bprm, ex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250#else
251 set_personality(PER_LINUX);
252#endif
Linus Torvalds221af7f2010-01-28 22:14:42 -0800253 setup_new_exec(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 current->mm->end_code = ex.a_text +
256 (current->mm->start_code = N_TXTADDR(ex));
257 current->mm->end_data = ex.a_data +
258 (current->mm->start_data = N_DATADDR(ex));
259 current->mm->brk = ex.a_bss +
260 (current->mm->start_brk = N_BSSADDR(ex));
261 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700262 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
David Howellsa6f76f22008-11-14 10:39:24 +1100264 install_exec_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 current->flags &= ~PF_FORKNOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
267 if (N_MAGIC(ex) == OMAGIC) {
268 unsigned long text_addr, map_size;
269 loff_t pos;
270
271 text_addr = N_TXTADDR(ex);
272
Al Virofe30af92009-01-03 07:16:13 +0000273#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 pos = fd_offset;
275 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
276#else
277 pos = 32;
278 map_size = ex.a_text+ex.a_data;
279#endif
280 down_write(&current->mm->mmap_sem);
281 error = do_brk(text_addr & PAGE_MASK, map_size);
282 up_write(&current->mm->mmap_sem);
283 if (error != (text_addr & PAGE_MASK)) {
284 send_sig(SIGKILL, current, 0);
285 return error;
286 }
287
288 error = bprm->file->f_op->read(bprm->file,
289 (char __user *)text_addr,
290 ex.a_text+ex.a_data, &pos);
291 if ((signed long)error < 0) {
292 send_sig(SIGKILL, current, 0);
293 return error;
294 }
295
296 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
297 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700299 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 {
301 printk(KERN_NOTICE "executable not page aligned\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 }
303
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700304 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 {
306 printk(KERN_WARNING
307 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800308 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 }
310
311 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
312 loff_t pos = fd_offset;
313 down_write(&current->mm->mmap_sem);
314 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
315 up_write(&current->mm->mmap_sem);
316 bprm->file->f_op->read(bprm->file,
317 (char __user *)N_TXTADDR(ex),
318 ex.a_text+ex.a_data, &pos);
319 flush_icache_range((unsigned long) N_TXTADDR(ex),
320 (unsigned long) N_TXTADDR(ex) +
321 ex.a_text+ex.a_data);
322 goto beyond_if;
323 }
324
325 down_write(&current->mm->mmap_sem);
326 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
327 PROT_READ | PROT_EXEC,
328 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
329 fd_offset);
330 up_write(&current->mm->mmap_sem);
331
332 if (error != N_TXTADDR(ex)) {
333 send_sig(SIGKILL, current, 0);
334 return error;
335 }
336
337 down_write(&current->mm->mmap_sem);
338 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
339 PROT_READ | PROT_WRITE | PROT_EXEC,
340 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
341 fd_offset + ex.a_text);
342 up_write(&current->mm->mmap_sem);
343 if (error != N_DATADDR(ex)) {
344 send_sig(SIGKILL, current, 0);
345 return error;
346 }
347 }
348beyond_if:
349 set_binfmt(&aout_format);
350
351 retval = set_brk(current->mm->start_brk, current->mm->brk);
352 if (retval < 0) {
353 send_sig(SIGKILL, current, 0);
354 return retval;
355 }
356
357 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
358 if (retval < 0) {
359 /* Someone check-me: is this error path enough? */
360 send_sig(SIGKILL, current, 0);
361 return retval;
362 }
363
364 current->mm->start_stack =
365 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
366#ifdef __alpha__
367 regs->gp = ex.a_gpvalue;
368#endif
369 start_thread(regs, ex.a_entry, current->mm->start_stack);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 return 0;
371}
372
373static int load_aout_library(struct file *file)
374{
375 struct inode * inode;
376 unsigned long bss, start_addr, len;
377 unsigned long error;
378 int retval;
379 struct exec ex;
380
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800381 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382
383 retval = -ENOEXEC;
384 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
385 if (error != sizeof(ex))
386 goto out;
387
388 /* We come in here for the regular a.out style of shared libraries */
389 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
390 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
391 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
392 goto out;
393 }
394
Eugene Teo8454aee2006-09-29 01:59:33 -0700395 /*
396 * Requires a mmap handler. This prevents people from using a.out
397 * as part of an exploit attack against /proc-related vulnerabilities.
398 */
399 if (!file->f_op || !file->f_op->mmap)
400 goto out;
401
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (N_FLAGS(ex))
403 goto out;
404
405 /* For QMAGIC, the starting address is 0x20 into the page. We mask
406 this off to get the starting address for the page */
407
408 start_addr = ex.a_entry & 0xfffff000;
409
410 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 loff_t pos = N_TXTOFF(ex);
412
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700413 if (printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 {
415 printk(KERN_WARNING
416 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800417 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 }
419 down_write(&current->mm->mmap_sem);
420 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
421 up_write(&current->mm->mmap_sem);
422
423 file->f_op->read(file, (char __user *)start_addr,
424 ex.a_text + ex.a_data, &pos);
425 flush_icache_range((unsigned long) start_addr,
426 (unsigned long) start_addr + ex.a_text + ex.a_data);
427
428 retval = 0;
429 goto out;
430 }
431 /* Now use mmap to map the library into memory. */
432 down_write(&current->mm->mmap_sem);
433 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
434 PROT_READ | PROT_WRITE | PROT_EXEC,
435 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
436 N_TXTOFF(ex));
437 up_write(&current->mm->mmap_sem);
438 retval = error;
439 if (error != start_addr)
440 goto out;
441
442 len = PAGE_ALIGN(ex.a_text + ex.a_data);
443 bss = ex.a_text + ex.a_data + ex.a_bss;
444 if (bss > len) {
445 down_write(&current->mm->mmap_sem);
446 error = do_brk(start_addr + len, bss - len);
447 up_write(&current->mm->mmap_sem);
448 retval = error;
449 if (error != start_addr + len)
450 goto out;
451 }
452 retval = 0;
453out:
454 return retval;
455}
456
457static int __init init_aout_binfmt(void)
458{
459 return register_binfmt(&aout_format);
460}
461
462static void __exit exit_aout_binfmt(void)
463{
464 unregister_binfmt(&aout_format);
465}
466
467core_initcall(init_aout_binfmt);
468module_exit(exit_aout_binfmt);
469MODULE_LICENSE("GPL");