Merge branch '3.4-rc1' into android-tegra-nv-3.3-rebased
[linux-2.6.git] / fs / binfmt_aout.c
1 /*
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/binfmts.h>
24 #include <linux/personality.h>
25 #include <linux/init.h>
26 #include <linux/coredump.h>
27 #include <linux/slab.h>
28
29 #include <asm/uaccess.h>
30 #include <asm/cacheflush.h>
31 #include <asm/a.out-core.h>
32
33 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
34 static int load_aout_library(struct file*);
35 static int aout_core_dump(struct coredump_params *cprm);
36
37 static 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
47 static 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  * Routine writes a core dump image in the current directory.
64  * Currently only a stub-function.
65  *
66  * Note that setuid/setgid files won't make a core-dump if the uid/gid
67  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
68  * field, which also makes sure the core-dumps won't be recursive if the
69  * dumping of the process results in another error..
70  */
71
72 static int aout_core_dump(struct coredump_params *cprm)
73 {
74         struct file *file = cprm->file;
75         mm_segment_t fs;
76         int has_dumped = 0;
77         void __user *dump_start;
78         int dump_size;
79         struct user dump;
80 #ifdef __alpha__
81 #       define START_DATA(u)    ((void __user *)u.start_data)
82 #else
83 #       define START_DATA(u)    ((void __user *)((u.u_tsize << PAGE_SHIFT) + \
84                                  u.start_code))
85 #endif
86 #       define START_STACK(u)   ((void __user *)u.start_stack)
87
88         fs = get_fs();
89         set_fs(KERNEL_DS);
90         has_dumped = 1;
91         current->flags |= PF_DUMPCORE;
92         strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
93         dump.u_ar0 = offsetof(struct user, regs);
94         dump.signal = cprm->signr;
95         aout_dump_thread(cprm->regs, &dump);
96
97 /* If the size of the dump file exceeds the rlimit, then see what would happen
98    if we wrote the stack, but not the data area.  */
99         if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
100                 dump.u_dsize = 0;
101
102 /* Make sure we have enough room to write the stack and data areas. */
103         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
104                 dump.u_ssize = 0;
105
106 /* make sure we actually have a data and stack area to dump */
107         set_fs(USER_DS);
108         if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
109                 dump.u_dsize = 0;
110         if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
111                 dump.u_ssize = 0;
112
113         set_fs(KERNEL_DS);
114 /* struct user */
115         if (!dump_write(file, &dump, sizeof(dump)))
116                 goto end_coredump;
117 /* Now dump all of the user data.  Include malloced stuff as well */
118         if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
119                 goto end_coredump;
120 /* now we start writing out the user space info */
121         set_fs(USER_DS);
122 /* Dump the data area */
123         if (dump.u_dsize != 0) {
124                 dump_start = START_DATA(dump);
125                 dump_size = dump.u_dsize << PAGE_SHIFT;
126                 if (!dump_write(file, dump_start, dump_size))
127                         goto end_coredump;
128         }
129 /* Now prepare to dump the stack area */
130         if (dump.u_ssize != 0) {
131                 dump_start = START_STACK(dump);
132                 dump_size = dump.u_ssize << PAGE_SHIFT;
133                 if (!dump_write(file, dump_start, dump_size))
134                         goto end_coredump;
135         }
136 end_coredump:
137         set_fs(fs);
138         return has_dumped;
139 }
140
141 /*
142  * create_aout_tables() parses the env- and arg-strings in new user
143  * memory and creates the pointer tables from them, and puts their
144  * addresses on the "stack", returning the new stack pointer value.
145  */
146 static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
147 {
148         char __user * __user *argv;
149         char __user * __user *envp;
150         unsigned long __user *sp;
151         int argc = bprm->argc;
152         int envc = bprm->envc;
153
154         sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
155 #ifdef __alpha__
156 /* whee.. test-programs are so much fun. */
157         put_user(0, --sp);
158         put_user(0, --sp);
159         if (bprm->loader) {
160                 put_user(0, --sp);
161                 put_user(1003, --sp);
162                 put_user(bprm->loader, --sp);
163                 put_user(1002, --sp);
164         }
165         put_user(bprm->exec, --sp);
166         put_user(1001, --sp);
167 #endif
168         sp -= envc+1;
169         envp = (char __user * __user *) sp;
170         sp -= argc+1;
171         argv = (char __user * __user *) sp;
172 #ifndef __alpha__
173         put_user((unsigned long) envp,--sp);
174         put_user((unsigned long) argv,--sp);
175 #endif
176         put_user(argc,--sp);
177         current->mm->arg_start = (unsigned long) p;
178         while (argc-->0) {
179                 char c;
180                 put_user(p,argv++);
181                 do {
182                         get_user(c,p++);
183                 } while (c);
184         }
185         put_user(NULL,argv);
186         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
187         while (envc-->0) {
188                 char c;
189                 put_user(p,envp++);
190                 do {
191                         get_user(c,p++);
192                 } while (c);
193         }
194         put_user(NULL,envp);
195         current->mm->env_end = (unsigned long) p;
196         return sp;
197 }
198
199 /*
200  * These are the functions used to load a.out style executables and shared
201  * libraries.  There is no binary dependent code anywhere else.
202  */
203
204 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
205 {
206         struct exec ex;
207         unsigned long error;
208         unsigned long fd_offset;
209         unsigned long rlim;
210         int retval;
211
212         ex = *((struct exec *) bprm->buf);              /* exec-header */
213         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
214              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
215             N_TRSIZE(ex) || N_DRSIZE(ex) ||
216             i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
217                 return -ENOEXEC;
218         }
219
220         /*
221          * Requires a mmap handler. This prevents people from using a.out
222          * as part of an exploit attack against /proc-related vulnerabilities.
223          */
224         if (!bprm->file->f_op || !bprm->file->f_op->mmap)
225                 return -ENOEXEC;
226
227         fd_offset = N_TXTOFF(ex);
228
229         /* Check initial limits. This avoids letting people circumvent
230          * size limits imposed on them by creating programs with large
231          * arrays in the data or bss.
232          */
233         rlim = rlimit(RLIMIT_DATA);
234         if (rlim >= RLIM_INFINITY)
235                 rlim = ~0;
236         if (ex.a_data + ex.a_bss > rlim)
237                 return -ENOMEM;
238
239         /* Flush all traces of the currently running executable */
240         retval = flush_old_exec(bprm);
241         if (retval)
242                 return retval;
243
244         /* OK, This is the point of no return */
245 #ifdef __alpha__
246         SET_AOUT_PERSONALITY(bprm, ex);
247 #else
248         set_personality(PER_LINUX);
249 #endif
250         setup_new_exec(bprm);
251
252         current->mm->end_code = ex.a_text +
253                 (current->mm->start_code = N_TXTADDR(ex));
254         current->mm->end_data = ex.a_data +
255                 (current->mm->start_data = N_DATADDR(ex));
256         current->mm->brk = ex.a_bss +
257                 (current->mm->start_brk = N_BSSADDR(ex));
258         current->mm->free_area_cache = current->mm->mmap_base;
259         current->mm->cached_hole_size = 0;
260
261         retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
262         if (retval < 0) {
263                 /* Someone check-me: is this error path enough? */
264                 send_sig(SIGKILL, current, 0);
265                 return retval;
266         }
267
268         install_exec_creds(bprm);
269
270         if (N_MAGIC(ex) == OMAGIC) {
271                 unsigned long text_addr, map_size;
272                 loff_t pos;
273
274                 text_addr = N_TXTADDR(ex);
275
276 #ifdef __alpha__
277                 pos = fd_offset;
278                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
279 #else
280                 pos = 32;
281                 map_size = ex.a_text+ex.a_data;
282 #endif
283                 down_write(&current->mm->mmap_sem);
284                 error = do_brk(text_addr & PAGE_MASK, map_size);
285                 up_write(&current->mm->mmap_sem);
286                 if (error != (text_addr & PAGE_MASK)) {
287                         send_sig(SIGKILL, current, 0);
288                         return error;
289                 }
290
291                 error = bprm->file->f_op->read(bprm->file,
292                           (char __user *)text_addr,
293                           ex.a_text+ex.a_data, &pos);
294                 if ((signed long)error < 0) {
295                         send_sig(SIGKILL, current, 0);
296                         return error;
297                 }
298                          
299                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
300         } else {
301                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
302                     (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
303                 {
304                         printk(KERN_NOTICE "executable not page aligned\n");
305                 }
306
307                 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
308                 {
309                         printk(KERN_WARNING 
310                                "fd_offset is not page aligned. Please convert program: %s\n",
311                                bprm->file->f_path.dentry->d_name.name);
312                 }
313
314                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
315                         loff_t pos = fd_offset;
316                         down_write(&current->mm->mmap_sem);
317                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
318                         up_write(&current->mm->mmap_sem);
319                         bprm->file->f_op->read(bprm->file,
320                                         (char __user *)N_TXTADDR(ex),
321                                         ex.a_text+ex.a_data, &pos);
322                         flush_icache_range((unsigned long) N_TXTADDR(ex),
323                                            (unsigned long) N_TXTADDR(ex) +
324                                            ex.a_text+ex.a_data);
325                         goto beyond_if;
326                 }
327
328                 down_write(&current->mm->mmap_sem);
329                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
330                         PROT_READ | PROT_EXEC,
331                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
332                         fd_offset);
333                 up_write(&current->mm->mmap_sem);
334
335                 if (error != N_TXTADDR(ex)) {
336                         send_sig(SIGKILL, current, 0);
337                         return error;
338                 }
339
340                 down_write(&current->mm->mmap_sem);
341                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
342                                 PROT_READ | PROT_WRITE | PROT_EXEC,
343                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
344                                 fd_offset + ex.a_text);
345                 up_write(&current->mm->mmap_sem);
346                 if (error != N_DATADDR(ex)) {
347                         send_sig(SIGKILL, current, 0);
348                         return error;
349                 }
350         }
351 beyond_if:
352         set_binfmt(&aout_format);
353
354         retval = set_brk(current->mm->start_brk, current->mm->brk);
355         if (retval < 0) {
356                 send_sig(SIGKILL, current, 0);
357                 return retval;
358         }
359
360         current->mm->start_stack =
361                 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
362 #ifdef __alpha__
363         regs->gp = ex.a_gpvalue;
364 #endif
365         start_thread(regs, ex.a_entry, current->mm->start_stack);
366         return 0;
367 }
368
369 static int load_aout_library(struct file *file)
370 {
371         struct inode * inode;
372         unsigned long bss, start_addr, len;
373         unsigned long error;
374         int retval;
375         struct exec ex;
376
377         inode = file->f_path.dentry->d_inode;
378
379         retval = -ENOEXEC;
380         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
381         if (error != sizeof(ex))
382                 goto out;
383
384         /* We come in here for the regular a.out style of shared libraries */
385         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
386             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
387             i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
388                 goto out;
389         }
390
391         /*
392          * Requires a mmap handler. This prevents people from using a.out
393          * as part of an exploit attack against /proc-related vulnerabilities.
394          */
395         if (!file->f_op || !file->f_op->mmap)
396                 goto out;
397
398         if (N_FLAGS(ex))
399                 goto out;
400
401         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
402            this off to get the starting address for the page */
403
404         start_addr =  ex.a_entry & 0xfffff000;
405
406         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
407                 loff_t pos = N_TXTOFF(ex);
408
409                 if (printk_ratelimit())
410                 {
411                         printk(KERN_WARNING 
412                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
413                                file->f_path.dentry->d_name.name);
414                 }
415                 down_write(&current->mm->mmap_sem);
416                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
417                 up_write(&current->mm->mmap_sem);
418                 
419                 file->f_op->read(file, (char __user *)start_addr,
420                         ex.a_text + ex.a_data, &pos);
421                 flush_icache_range((unsigned long) start_addr,
422                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
423
424                 retval = 0;
425                 goto out;
426         }
427         /* Now use mmap to map the library into memory. */
428         down_write(&current->mm->mmap_sem);
429         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
430                         PROT_READ | PROT_WRITE | PROT_EXEC,
431                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
432                         N_TXTOFF(ex));
433         up_write(&current->mm->mmap_sem);
434         retval = error;
435         if (error != start_addr)
436                 goto out;
437
438         len = PAGE_ALIGN(ex.a_text + ex.a_data);
439         bss = ex.a_text + ex.a_data + ex.a_bss;
440         if (bss > len) {
441                 down_write(&current->mm->mmap_sem);
442                 error = do_brk(start_addr + len, bss - len);
443                 up_write(&current->mm->mmap_sem);
444                 retval = error;
445                 if (error != start_addr + len)
446                         goto out;
447         }
448         retval = 0;
449 out:
450         return retval;
451 }
452
453 static int __init init_aout_binfmt(void)
454 {
455         register_binfmt(&aout_format);
456         return 0;
457 }
458
459 static void __exit exit_aout_binfmt(void)
460 {
461         unregister_binfmt(&aout_format);
462 }
463
464 core_initcall(init_aout_binfmt);
465 module_exit(exit_aout_binfmt);
466 MODULE_LICENSE("GPL");