GFS2: do not select QUOTA
[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/slab.h>
24 #include <linux/binfmts.h>
25 #include <linux/personality.h>
26 #include <linux/init.h>
27 #include <linux/coredump.h>
28
29 #include <asm/system.h>
30 #include <asm/uaccess.h>
31 #include <asm/cacheflush.h>
32 #include <asm/a.out-core.h>
33
34 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
35 static int load_aout_library(struct file*);
36 static int aout_core_dump(struct coredump_params *cprm);
37
38 static 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
48 static 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 /*
64  * 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
73 static int aout_core_dump(struct coredump_params *cprm)
74 {
75         struct file *file = cprm->file;
76         mm_segment_t fs;
77         int has_dumped = 0;
78         unsigned long dump_start, dump_size;
79         struct user dump;
80 #ifdef __alpha__
81 #       define START_DATA(u)    (u.start_data)
82 #else
83 #       define START_DATA(u)    ((u.u_tsize << PAGE_SHIFT) + u.start_code)
84 #endif
85 #       define START_STACK(u)   (u.start_stack)
86
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));
92         dump.u_ar0 = offsetof(struct user, regs);
93         dump.signal = cprm->signr;
94         aout_dump_thread(cprm->regs, &dump);
95
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.  */
98         if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
99                 dump.u_dsize = 0;
100
101 /* Make sure we have enough room to write the stack and data areas. */
102         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
103                 dump.u_ssize = 0;
104
105 /* make sure we actually have a data and stack area to dump */
106         set_fs(USER_DS);
107         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;
111
112         set_fs(KERNEL_DS);
113 /* struct user */
114         if (!dump_write(file, &dump, sizeof(dump)))
115                 goto end_coredump;
116 /* Now dump all of the user data.  Include malloced stuff as well */
117         if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
118                 goto end_coredump;
119 /* 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);
124                 dump_size = dump.u_dsize << PAGE_SHIFT;
125                 if (!dump_write(file, dump_start, dump_size))
126                         goto end_coredump;
127         }
128 /* Now prepare to dump the stack area */
129         if (dump.u_ssize != 0) {
130                 dump_start = START_STACK(dump);
131                 dump_size = dump.u_ssize << PAGE_SHIFT;
132                 if (!dump_write(file, dump_start, dump_size))
133                         goto end_coredump;
134         }
135 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
136         set_fs(KERNEL_DS);
137         if (!dump_write(file, current, sizeof(*current)))
138                 goto end_coredump;
139 end_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  */
149 static 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);
158 #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);
164                 put_user(1003, --sp);
165                 put_user(bprm->loader, --sp);
166                 put_user(1002, --sp);
167         }
168         put_user(bprm->exec, --sp);
169         put_user(1001, --sp);
170 #endif
171         sp -= envc+1;
172         envp = (char __user * __user *) sp;
173         sp -= argc+1;
174         argv = (char __user * __user *) sp;
175 #ifndef __alpha__
176         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
207 static 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) ||
219             i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
220                 return -ENOEXEC;
221         }
222
223         /*
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
230         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          */
236         rlim = rlimit(RLIMIT_DATA);
237         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 */
248 #ifdef __alpha__
249         SET_AOUT_PERSONALITY(bprm, ex);
250 #else
251         set_personality(PER_LINUX);
252 #endif
253         setup_new_exec(bprm);
254
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;
262         current->mm->cached_hole_size = 0;
263
264         install_exec_creds(bprm);
265         current->flags &= ~PF_FORKNOEXEC;
266
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
273 #ifdef __alpha__
274                 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 {
298                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
299                     (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
300                 {
301                         printk(KERN_NOTICE "executable not page aligned\n");
302                 }
303
304                 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
305                 {
306                         printk(KERN_WARNING 
307                                "fd_offset is not page aligned. Please convert program: %s\n",
308                                bprm->file->f_path.dentry->d_name.name);
309                 }
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         }
348 beyond_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);
370         return 0;
371 }
372
373 static 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
381         inode = file->f_path.dentry->d_inode;
382
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
395         /*
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
402         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) {
411                 loff_t pos = N_TXTOFF(ex);
412
413                 if (printk_ratelimit())
414                 {
415                         printk(KERN_WARNING 
416                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
417                                file->f_path.dentry->d_name.name);
418                 }
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;
453 out:
454         return retval;
455 }
456
457 static int __init init_aout_binfmt(void)
458 {
459         return register_binfmt(&aout_format);
460 }
461
462 static void __exit exit_aout_binfmt(void)
463 {
464         unregister_binfmt(&aout_format);
465 }
466
467 core_initcall(init_aout_binfmt);
468 module_exit(exit_aout_binfmt);
469 MODULE_LICENSE("GPL");