blob: f96eff04e11ab4a8b23f7489ee4b0de50e67e152 [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 }
137/* Finally dump the task struct. Not be used by gdb, but could be useful */
138 set_fs(KERNEL_DS);
Daisuke HATAYAMA088e7af2010-03-05 13:44:06 -0800139 if (!dump_write(file, current, sizeof(*current)))
140 goto end_coredump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141end_coredump:
142 set_fs(fs);
143 return has_dumped;
144}
145
146/*
147 * create_aout_tables() parses the env- and arg-strings in new user
148 * memory and creates the pointer tables from them, and puts their
149 * addresses on the "stack", returning the new stack pointer value.
150 */
151static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
152{
153 char __user * __user *argv;
154 char __user * __user *envp;
155 unsigned long __user *sp;
156 int argc = bprm->argc;
157 int envc = bprm->envc;
158
159 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160#ifdef __alpha__
161/* whee.. test-programs are so much fun. */
162 put_user(0, --sp);
163 put_user(0, --sp);
164 if (bprm->loader) {
165 put_user(0, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000166 put_user(1003, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 put_user(bprm->loader, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000168 put_user(1002, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 }
170 put_user(bprm->exec, --sp);
Al Viro17580d72009-01-03 07:16:23 +0000171 put_user(1001, --sp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172#endif
173 sp -= envc+1;
174 envp = (char __user * __user *) sp;
175 sp -= argc+1;
176 argv = (char __user * __user *) sp;
Al Viro17580d72009-01-03 07:16:23 +0000177#ifndef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 put_user((unsigned long) envp,--sp);
179 put_user((unsigned long) argv,--sp);
180#endif
181 put_user(argc,--sp);
182 current->mm->arg_start = (unsigned long) p;
183 while (argc-->0) {
184 char c;
185 put_user(p,argv++);
186 do {
187 get_user(c,p++);
188 } while (c);
189 }
190 put_user(NULL,argv);
191 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
192 while (envc-->0) {
193 char c;
194 put_user(p,envp++);
195 do {
196 get_user(c,p++);
197 } while (c);
198 }
199 put_user(NULL,envp);
200 current->mm->env_end = (unsigned long) p;
201 return sp;
202}
203
204/*
205 * These are the functions used to load a.out style executables and shared
206 * libraries. There is no binary dependent code anywhere else.
207 */
208
209static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
210{
211 struct exec ex;
212 unsigned long error;
213 unsigned long fd_offset;
214 unsigned long rlim;
215 int retval;
216
217 ex = *((struct exec *) bprm->buf); /* exec-header */
218 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
219 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
220 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800221 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 -0700222 return -ENOEXEC;
223 }
224
Eugene Teo8454aee2006-09-29 01:59:33 -0700225 /*
226 * Requires a mmap handler. This prevents people from using a.out
227 * as part of an exploit attack against /proc-related vulnerabilities.
228 */
229 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
230 return -ENOEXEC;
231
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 fd_offset = N_TXTOFF(ex);
233
234 /* Check initial limits. This avoids letting people circumvent
235 * size limits imposed on them by creating programs with large
236 * arrays in the data or bss.
237 */
Jiri Slabyd554ed892010-03-05 13:42:42 -0800238 rlim = rlimit(RLIMIT_DATA);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 if (rlim >= RLIM_INFINITY)
240 rlim = ~0;
241 if (ex.a_data + ex.a_bss > rlim)
242 return -ENOMEM;
243
244 /* Flush all traces of the currently running executable */
245 retval = flush_old_exec(bprm);
246 if (retval)
247 return retval;
248
249 /* OK, This is the point of no return */
Al Viro17580d72009-01-03 07:16:23 +0000250#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 SET_AOUT_PERSONALITY(bprm, ex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252#else
253 set_personality(PER_LINUX);
254#endif
Linus Torvalds221af7f2010-01-28 22:14:42 -0800255 setup_new_exec(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
257 current->mm->end_code = ex.a_text +
258 (current->mm->start_code = N_TXTADDR(ex));
259 current->mm->end_data = ex.a_data +
260 (current->mm->start_data = N_DATADDR(ex));
261 current->mm->brk = ex.a_bss +
262 (current->mm->start_brk = N_BSSADDR(ex));
263 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700264 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265
David Howellsa6f76f22008-11-14 10:39:24 +1100266 install_exec_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 current->flags &= ~PF_FORKNOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
269 if (N_MAGIC(ex) == OMAGIC) {
270 unsigned long text_addr, map_size;
271 loff_t pos;
272
273 text_addr = N_TXTADDR(ex);
274
Al Virofe30af92009-01-03 07:16:13 +0000275#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 pos = fd_offset;
277 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
278#else
279 pos = 32;
280 map_size = ex.a_text+ex.a_data;
281#endif
282 down_write(&current->mm->mmap_sem);
283 error = do_brk(text_addr & PAGE_MASK, map_size);
284 up_write(&current->mm->mmap_sem);
285 if (error != (text_addr & PAGE_MASK)) {
286 send_sig(SIGKILL, current, 0);
287 return error;
288 }
289
290 error = bprm->file->f_op->read(bprm->file,
291 (char __user *)text_addr,
292 ex.a_text+ex.a_data, &pos);
293 if ((signed long)error < 0) {
294 send_sig(SIGKILL, current, 0);
295 return error;
296 }
297
298 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
299 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700301 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 {
303 printk(KERN_NOTICE "executable not page aligned\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 }
305
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700306 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 {
308 printk(KERN_WARNING
309 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800310 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 }
312
313 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
314 loff_t pos = fd_offset;
315 down_write(&current->mm->mmap_sem);
316 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
317 up_write(&current->mm->mmap_sem);
318 bprm->file->f_op->read(bprm->file,
319 (char __user *)N_TXTADDR(ex),
320 ex.a_text+ex.a_data, &pos);
321 flush_icache_range((unsigned long) N_TXTADDR(ex),
322 (unsigned long) N_TXTADDR(ex) +
323 ex.a_text+ex.a_data);
324 goto beyond_if;
325 }
326
327 down_write(&current->mm->mmap_sem);
328 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
329 PROT_READ | PROT_EXEC,
330 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
331 fd_offset);
332 up_write(&current->mm->mmap_sem);
333
334 if (error != N_TXTADDR(ex)) {
335 send_sig(SIGKILL, current, 0);
336 return error;
337 }
338
339 down_write(&current->mm->mmap_sem);
340 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
341 PROT_READ | PROT_WRITE | PROT_EXEC,
342 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
343 fd_offset + ex.a_text);
344 up_write(&current->mm->mmap_sem);
345 if (error != N_DATADDR(ex)) {
346 send_sig(SIGKILL, current, 0);
347 return error;
348 }
349 }
350beyond_if:
351 set_binfmt(&aout_format);
352
353 retval = set_brk(current->mm->start_brk, current->mm->brk);
354 if (retval < 0) {
355 send_sig(SIGKILL, current, 0);
356 return retval;
357 }
358
359 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
360 if (retval < 0) {
361 /* Someone check-me: is this error path enough? */
362 send_sig(SIGKILL, current, 0);
363 return retval;
364 }
365
366 current->mm->start_stack =
367 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
368#ifdef __alpha__
369 regs->gp = ex.a_gpvalue;
370#endif
371 start_thread(regs, ex.a_entry, current->mm->start_stack);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 return 0;
373}
374
375static int load_aout_library(struct file *file)
376{
377 struct inode * inode;
378 unsigned long bss, start_addr, len;
379 unsigned long error;
380 int retval;
381 struct exec ex;
382
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800383 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384
385 retval = -ENOEXEC;
386 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
387 if (error != sizeof(ex))
388 goto out;
389
390 /* We come in here for the regular a.out style of shared libraries */
391 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
392 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
393 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
394 goto out;
395 }
396
Eugene Teo8454aee2006-09-29 01:59:33 -0700397 /*
398 * Requires a mmap handler. This prevents people from using a.out
399 * as part of an exploit attack against /proc-related vulnerabilities.
400 */
401 if (!file->f_op || !file->f_op->mmap)
402 goto out;
403
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 if (N_FLAGS(ex))
405 goto out;
406
407 /* For QMAGIC, the starting address is 0x20 into the page. We mask
408 this off to get the starting address for the page */
409
410 start_addr = ex.a_entry & 0xfffff000;
411
412 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 loff_t pos = N_TXTOFF(ex);
414
S.Caglar Onur2e50b6c2008-04-29 00:59:26 -0700415 if (printk_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 {
417 printk(KERN_WARNING
418 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800419 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 }
421 down_write(&current->mm->mmap_sem);
422 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
423 up_write(&current->mm->mmap_sem);
424
425 file->f_op->read(file, (char __user *)start_addr,
426 ex.a_text + ex.a_data, &pos);
427 flush_icache_range((unsigned long) start_addr,
428 (unsigned long) start_addr + ex.a_text + ex.a_data);
429
430 retval = 0;
431 goto out;
432 }
433 /* Now use mmap to map the library into memory. */
434 down_write(&current->mm->mmap_sem);
435 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
436 PROT_READ | PROT_WRITE | PROT_EXEC,
437 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
438 N_TXTOFF(ex));
439 up_write(&current->mm->mmap_sem);
440 retval = error;
441 if (error != start_addr)
442 goto out;
443
444 len = PAGE_ALIGN(ex.a_text + ex.a_data);
445 bss = ex.a_text + ex.a_data + ex.a_bss;
446 if (bss > len) {
447 down_write(&current->mm->mmap_sem);
448 error = do_brk(start_addr + len, bss - len);
449 up_write(&current->mm->mmap_sem);
450 retval = error;
451 if (error != start_addr + len)
452 goto out;
453 }
454 retval = 0;
455out:
456 return retval;
457}
458
459static int __init init_aout_binfmt(void)
460{
461 return register_binfmt(&aout_format);
462}
463
464static void __exit exit_aout_binfmt(void)
465{
466 unregister_binfmt(&aout_format);
467}
468
469core_initcall(init_aout_binfmt);
470module_exit(exit_aout_binfmt);
471MODULE_LICENSE("GPL");