blob: 8a3b32f5b781b17a58ba2e474ec03d583b25a83c [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*);
Neil Horman7dc0b222007-10-16 23:26:34 -070035static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
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
Neil Horman7dc0b222007-10-16 23:26:34 -070092static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
94 mm_segment_t fs;
95 int has_dumped = 0;
96 unsigned long dump_start, dump_size;
97 struct user dump;
98#if defined(__alpha__)
99# define START_DATA(u) (u.start_data)
100#elif defined(__arm__)
101# define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102#elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
103# define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
104#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105# define START_STACK(u) (u.start_stack)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107 fs = get_fs();
108 set_fs(KERNEL_DS);
109 has_dumped = 1;
110 current->flags |= PF_DUMPCORE;
111 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
H. Peter Anvin6e16d892008-02-07 00:15:57 -0800112 dump.u_ar0 = offsetof(struct user, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 dump.signal = signr;
David Howells7fa30312008-02-08 04:19:28 -0800114 aout_dump_thread(regs, &dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116/* If the size of the dump file exceeds the rlimit, then see what would happen
117 if we wrote the stack, but not the data area. */
Neil Horman7dc0b222007-10-16 23:26:34 -0700118 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 dump.u_dsize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121/* Make sure we have enough room to write the stack and data areas. */
Neil Horman7dc0b222007-10-16 23:26:34 -0700122 if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
125/* make sure we actually have a data and stack area to dump */
126 set_fs(USER_DS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
128 dump.u_dsize = 0;
129 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
130 dump.u_ssize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132 set_fs(KERNEL_DS);
133/* struct user */
134 DUMP_WRITE(&dump,sizeof(dump));
135/* Now dump all of the user data. Include malloced stuff as well */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 DUMP_SEEK(PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137/* now we start writing out the user space info */
138 set_fs(USER_DS);
139/* Dump the data area */
140 if (dump.u_dsize != 0) {
141 dump_start = START_DATA(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 dump_size = dump.u_dsize << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 DUMP_WRITE(dump_start,dump_size);
144 }
145/* Now prepare to dump the stack area */
146 if (dump.u_ssize != 0) {
147 dump_start = START_STACK(dump);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 dump_size = dump.u_ssize << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 DUMP_WRITE(dump_start,dump_size);
150 }
151/* Finally dump the task struct. Not be used by gdb, but could be useful */
152 set_fs(KERNEL_DS);
153 DUMP_WRITE(current,sizeof(*current));
154end_coredump:
155 set_fs(fs);
156 return has_dumped;
157}
158
159/*
160 * create_aout_tables() parses the env- and arg-strings in new user
161 * memory and creates the pointer tables from them, and puts their
162 * addresses on the "stack", returning the new stack pointer value.
163 */
164static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
165{
166 char __user * __user *argv;
167 char __user * __user *envp;
168 unsigned long __user *sp;
169 int argc = bprm->argc;
170 int envc = bprm->envc;
171
172 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173#ifdef __alpha__
174/* whee.. test-programs are so much fun. */
175 put_user(0, --sp);
176 put_user(0, --sp);
177 if (bprm->loader) {
178 put_user(0, --sp);
179 put_user(0x3eb, --sp);
180 put_user(bprm->loader, --sp);
181 put_user(0x3ea, --sp);
182 }
183 put_user(bprm->exec, --sp);
184 put_user(0x3e9, --sp);
185#endif
186 sp -= envc+1;
187 envp = (char __user * __user *) sp;
188 sp -= argc+1;
189 argv = (char __user * __user *) sp;
190#if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
191 put_user((unsigned long) envp,--sp);
192 put_user((unsigned long) argv,--sp);
193#endif
194 put_user(argc,--sp);
195 current->mm->arg_start = (unsigned long) p;
196 while (argc-->0) {
197 char c;
198 put_user(p,argv++);
199 do {
200 get_user(c,p++);
201 } while (c);
202 }
203 put_user(NULL,argv);
204 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
205 while (envc-->0) {
206 char c;
207 put_user(p,envp++);
208 do {
209 get_user(c,p++);
210 } while (c);
211 }
212 put_user(NULL,envp);
213 current->mm->env_end = (unsigned long) p;
214 return sp;
215}
216
217/*
218 * These are the functions used to load a.out style executables and shared
219 * libraries. There is no binary dependent code anywhere else.
220 */
221
222static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
223{
224 struct exec ex;
225 unsigned long error;
226 unsigned long fd_offset;
227 unsigned long rlim;
228 int retval;
229
230 ex = *((struct exec *) bprm->buf); /* exec-header */
231 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
232 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
233 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800234 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 -0700235 return -ENOEXEC;
236 }
237
Eugene Teo8454aee2006-09-29 01:59:33 -0700238 /*
239 * Requires a mmap handler. This prevents people from using a.out
240 * as part of an exploit attack against /proc-related vulnerabilities.
241 */
242 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
243 return -ENOEXEC;
244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 fd_offset = N_TXTOFF(ex);
246
247 /* Check initial limits. This avoids letting people circumvent
248 * size limits imposed on them by creating programs with large
249 * arrays in the data or bss.
250 */
251 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
252 if (rlim >= RLIM_INFINITY)
253 rlim = ~0;
254 if (ex.a_data + ex.a_bss > rlim)
255 return -ENOMEM;
256
257 /* Flush all traces of the currently running executable */
258 retval = flush_old_exec(bprm);
259 if (retval)
260 return retval;
261
262 /* OK, This is the point of no return */
263#if defined(__alpha__)
264 SET_AOUT_PERSONALITY(bprm, ex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265#else
266 set_personality(PER_LINUX);
267#endif
268
269 current->mm->end_code = ex.a_text +
270 (current->mm->start_code = N_TXTADDR(ex));
271 current->mm->end_data = ex.a_data +
272 (current->mm->start_data = N_DATADDR(ex));
273 current->mm->brk = ex.a_bss +
274 (current->mm->start_brk = N_BSSADDR(ex));
275 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700276 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
David Howellsa6f76f22008-11-14 10:39:24 +1100278 install_exec_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 current->flags &= ~PF_FORKNOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281 if (N_MAGIC(ex) == OMAGIC) {
282 unsigned long text_addr, map_size;
283 loff_t pos;
284
285 text_addr = N_TXTADDR(ex);
286
Al Virofe30af92009-01-03 07:16:13 +0000287#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 pos = fd_offset;
289 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
290#else
291 pos = 32;
292 map_size = ex.a_text+ex.a_data;
293#endif
294 down_write(&current->mm->mmap_sem);
295 error = do_brk(text_addr & PAGE_MASK, map_size);
296 up_write(&current->mm->mmap_sem);
297 if (error != (text_addr & PAGE_MASK)) {
298 send_sig(SIGKILL, current, 0);
299 return error;
300 }
301
302 error = bprm->file->f_op->read(bprm->file,
303 (char __user *)text_addr,
304 ex.a_text+ex.a_data, &pos);
305 if ((signed long)error < 0) {
306 send_sig(SIGKILL, current, 0);
307 return error;
308 }
309
310 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
311 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700313 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 {
315 printk(KERN_NOTICE "executable not page aligned\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 }
317
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700318 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 {
320 printk(KERN_WARNING
321 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800322 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 }
324
325 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
326 loff_t pos = fd_offset;
327 down_write(&current->mm->mmap_sem);
328 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
329 up_write(&current->mm->mmap_sem);
330 bprm->file->f_op->read(bprm->file,
331 (char __user *)N_TXTADDR(ex),
332 ex.a_text+ex.a_data, &pos);
333 flush_icache_range((unsigned long) N_TXTADDR(ex),
334 (unsigned long) N_TXTADDR(ex) +
335 ex.a_text+ex.a_data);
336 goto beyond_if;
337 }
338
339 down_write(&current->mm->mmap_sem);
340 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
341 PROT_READ | PROT_EXEC,
342 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
343 fd_offset);
344 up_write(&current->mm->mmap_sem);
345
346 if (error != N_TXTADDR(ex)) {
347 send_sig(SIGKILL, current, 0);
348 return error;
349 }
350
351 down_write(&current->mm->mmap_sem);
352 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
353 PROT_READ | PROT_WRITE | PROT_EXEC,
354 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
355 fd_offset + ex.a_text);
356 up_write(&current->mm->mmap_sem);
357 if (error != N_DATADDR(ex)) {
358 send_sig(SIGKILL, current, 0);
359 return error;
360 }
361 }
362beyond_if:
363 set_binfmt(&aout_format);
364
365 retval = set_brk(current->mm->start_brk, current->mm->brk);
366 if (retval < 0) {
367 send_sig(SIGKILL, current, 0);
368 return retval;
369 }
370
371 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
372 if (retval < 0) {
373 /* Someone check-me: is this error path enough? */
374 send_sig(SIGKILL, current, 0);
375 return retval;
376 }
377
378 current->mm->start_stack =
379 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
380#ifdef __alpha__
381 regs->gp = ex.a_gpvalue;
382#endif
383 start_thread(regs, ex.a_entry, current->mm->start_stack);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 return 0;
385}
386
387static int load_aout_library(struct file *file)
388{
389 struct inode * inode;
390 unsigned long bss, start_addr, len;
391 unsigned long error;
392 int retval;
393 struct exec ex;
394
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800395 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396
397 retval = -ENOEXEC;
398 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
399 if (error != sizeof(ex))
400 goto out;
401
402 /* We come in here for the regular a.out style of shared libraries */
403 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
404 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
405 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
406 goto out;
407 }
408
Eugene Teo8454aee2006-09-29 01:59:33 -0700409 /*
410 * Requires a mmap handler. This prevents people from using a.out
411 * as part of an exploit attack against /proc-related vulnerabilities.
412 */
413 if (!file->f_op || !file->f_op->mmap)
414 goto out;
415
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 if (N_FLAGS(ex))
417 goto out;
418
419 /* For QMAGIC, the starting address is 0x20 into the page. We mask
420 this off to get the starting address for the page */
421
422 start_addr = ex.a_entry & 0xfffff000;
423
424 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 loff_t pos = N_TXTOFF(ex);
426
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700427 if (printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 {
429 printk(KERN_WARNING
430 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800431 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 }
433 down_write(&current->mm->mmap_sem);
434 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
435 up_write(&current->mm->mmap_sem);
436
437 file->f_op->read(file, (char __user *)start_addr,
438 ex.a_text + ex.a_data, &pos);
439 flush_icache_range((unsigned long) start_addr,
440 (unsigned long) start_addr + ex.a_text + ex.a_data);
441
442 retval = 0;
443 goto out;
444 }
445 /* Now use mmap to map the library into memory. */
446 down_write(&current->mm->mmap_sem);
447 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
448 PROT_READ | PROT_WRITE | PROT_EXEC,
449 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
450 N_TXTOFF(ex));
451 up_write(&current->mm->mmap_sem);
452 retval = error;
453 if (error != start_addr)
454 goto out;
455
456 len = PAGE_ALIGN(ex.a_text + ex.a_data);
457 bss = ex.a_text + ex.a_data + ex.a_bss;
458 if (bss > len) {
459 down_write(&current->mm->mmap_sem);
460 error = do_brk(start_addr + len, bss - len);
461 up_write(&current->mm->mmap_sem);
462 retval = error;
463 if (error != start_addr + len)
464 goto out;
465 }
466 retval = 0;
467out:
468 return retval;
469}
470
471static int __init init_aout_binfmt(void)
472{
473 return register_binfmt(&aout_format);
474}
475
476static void __exit exit_aout_binfmt(void)
477{
478 unregister_binfmt(&aout_format);
479}
480
481core_initcall(init_aout_binfmt);
482module_exit(exit_aout_binfmt);
483MODULE_LICENSE("GPL");