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Commit | Line | Data |
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1da177e4 LT |
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 | ||
28 | #include <asm/system.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/cacheflush.h> | |
7fa30315 | 31 | #include <asm/a.out-core.h> |
1da177e4 LT |
32 | |
33 | static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); | |
34 | static int load_aout_library(struct file*); | |
f6151dfe | 35 | static int aout_core_dump(struct coredump_params *cprm); |
1da177e4 | 36 | |
1da177e4 LT |
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(¤t->mm->mmap_sem); | |
54 | addr = do_brk(start, end - start); | |
55 | up_write(¤t->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 | ||
67 | static 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 | ||
05f47fda DH |
72 | static int dump_seek(struct file *file, loff_t off) |
73 | { | |
74 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { | |
75 | if (file->f_op->llseek(file, off, SEEK_CUR) < 0) | |
76 | return 0; | |
77 | } else { | |
78 | char *buf = (char *)get_zeroed_page(GFP_KERNEL); | |
79 | if (!buf) | |
80 | return 0; | |
81 | while (off > 0) { | |
82 | unsigned long n = off; | |
83 | if (n > PAGE_SIZE) | |
84 | n = PAGE_SIZE; | |
85 | if (!dump_write(file, buf, n)) | |
86 | return 0; | |
87 | off -= n; | |
88 | } | |
89 | free_page((unsigned long)buf); | |
90 | } | |
91 | return 1; | |
92 | } | |
93 | ||
1da177e4 LT |
94 | #define DUMP_WRITE(addr, nr) \ |
95 | if (!dump_write(file, (void *)(addr), (nr))) \ | |
96 | goto end_coredump; | |
97 | ||
1da177e4 LT |
98 | /* |
99 | * Routine writes a core dump image in the current directory. | |
100 | * Currently only a stub-function. | |
101 | * | |
102 | * Note that setuid/setgid files won't make a core-dump if the uid/gid | |
103 | * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" | |
104 | * field, which also makes sure the core-dumps won't be recursive if the | |
105 | * dumping of the process results in another error.. | |
106 | */ | |
107 | ||
f6151dfe | 108 | static int aout_core_dump(struct coredump_params *cprm) |
1da177e4 | 109 | { |
f6151dfe | 110 | struct file *file = cprm->file; |
1da177e4 LT |
111 | mm_segment_t fs; |
112 | int has_dumped = 0; | |
113 | unsigned long dump_start, dump_size; | |
114 | struct user dump; | |
17580d7f | 115 | #ifdef __alpha__ |
1da177e4 | 116 | # define START_DATA(u) (u.start_data) |
17580d7f | 117 | #else |
1da177e4 | 118 | # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code) |
1da177e4 | 119 | #endif |
1da177e4 | 120 | # define START_STACK(u) (u.start_stack) |
1da177e4 LT |
121 | |
122 | fs = get_fs(); | |
123 | set_fs(KERNEL_DS); | |
124 | has_dumped = 1; | |
125 | current->flags |= PF_DUMPCORE; | |
126 | strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); | |
6e16d89b | 127 | dump.u_ar0 = offsetof(struct user, regs); |
f6151dfe MH |
128 | dump.signal = cprm->signr; |
129 | aout_dump_thread(cprm->regs, &dump); | |
1da177e4 LT |
130 | |
131 | /* If the size of the dump file exceeds the rlimit, then see what would happen | |
132 | if we wrote the stack, but not the data area. */ | |
f6151dfe | 133 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 134 | dump.u_dsize = 0; |
1da177e4 LT |
135 | |
136 | /* Make sure we have enough room to write the stack and data areas. */ | |
f6151dfe | 137 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 138 | dump.u_ssize = 0; |
1da177e4 LT |
139 | |
140 | /* make sure we actually have a data and stack area to dump */ | |
141 | set_fs(USER_DS); | |
1da177e4 LT |
142 | if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
143 | dump.u_dsize = 0; | |
144 | if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) | |
145 | dump.u_ssize = 0; | |
1da177e4 LT |
146 | |
147 | set_fs(KERNEL_DS); | |
148 | /* struct user */ | |
149 | DUMP_WRITE(&dump,sizeof(dump)); | |
150 | /* Now dump all of the user data. Include malloced stuff as well */ | |
05f47fda DH |
151 | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
152 | goto end_coredump; | |
1da177e4 LT |
153 | /* now we start writing out the user space info */ |
154 | set_fs(USER_DS); | |
155 | /* Dump the data area */ | |
156 | if (dump.u_dsize != 0) { | |
157 | dump_start = START_DATA(dump); | |
1da177e4 | 158 | dump_size = dump.u_dsize << PAGE_SHIFT; |
1da177e4 LT |
159 | DUMP_WRITE(dump_start,dump_size); |
160 | } | |
161 | /* Now prepare to dump the stack area */ | |
162 | if (dump.u_ssize != 0) { | |
163 | dump_start = START_STACK(dump); | |
1da177e4 | 164 | dump_size = dump.u_ssize << PAGE_SHIFT; |
1da177e4 LT |
165 | DUMP_WRITE(dump_start,dump_size); |
166 | } | |
167 | /* Finally dump the task struct. Not be used by gdb, but could be useful */ | |
168 | set_fs(KERNEL_DS); | |
169 | DUMP_WRITE(current,sizeof(*current)); | |
170 | end_coredump: | |
171 | set_fs(fs); | |
172 | return has_dumped; | |
173 | } | |
174 | ||
175 | /* | |
176 | * create_aout_tables() parses the env- and arg-strings in new user | |
177 | * memory and creates the pointer tables from them, and puts their | |
178 | * addresses on the "stack", returning the new stack pointer value. | |
179 | */ | |
180 | static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) | |
181 | { | |
182 | char __user * __user *argv; | |
183 | char __user * __user *envp; | |
184 | unsigned long __user *sp; | |
185 | int argc = bprm->argc; | |
186 | int envc = bprm->envc; | |
187 | ||
188 | sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); | |
1da177e4 LT |
189 | #ifdef __alpha__ |
190 | /* whee.. test-programs are so much fun. */ | |
191 | put_user(0, --sp); | |
192 | put_user(0, --sp); | |
193 | if (bprm->loader) { | |
194 | put_user(0, --sp); | |
17580d7f | 195 | put_user(1003, --sp); |
1da177e4 | 196 | put_user(bprm->loader, --sp); |
17580d7f | 197 | put_user(1002, --sp); |
1da177e4 LT |
198 | } |
199 | put_user(bprm->exec, --sp); | |
17580d7f | 200 | put_user(1001, --sp); |
1da177e4 LT |
201 | #endif |
202 | sp -= envc+1; | |
203 | envp = (char __user * __user *) sp; | |
204 | sp -= argc+1; | |
205 | argv = (char __user * __user *) sp; | |
17580d7f | 206 | #ifndef __alpha__ |
1da177e4 LT |
207 | put_user((unsigned long) envp,--sp); |
208 | put_user((unsigned long) argv,--sp); | |
209 | #endif | |
210 | put_user(argc,--sp); | |
211 | current->mm->arg_start = (unsigned long) p; | |
212 | while (argc-->0) { | |
213 | char c; | |
214 | put_user(p,argv++); | |
215 | do { | |
216 | get_user(c,p++); | |
217 | } while (c); | |
218 | } | |
219 | put_user(NULL,argv); | |
220 | current->mm->arg_end = current->mm->env_start = (unsigned long) p; | |
221 | while (envc-->0) { | |
222 | char c; | |
223 | put_user(p,envp++); | |
224 | do { | |
225 | get_user(c,p++); | |
226 | } while (c); | |
227 | } | |
228 | put_user(NULL,envp); | |
229 | current->mm->env_end = (unsigned long) p; | |
230 | return sp; | |
231 | } | |
232 | ||
233 | /* | |
234 | * These are the functions used to load a.out style executables and shared | |
235 | * libraries. There is no binary dependent code anywhere else. | |
236 | */ | |
237 | ||
238 | static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs) | |
239 | { | |
240 | struct exec ex; | |
241 | unsigned long error; | |
242 | unsigned long fd_offset; | |
243 | unsigned long rlim; | |
244 | int retval; | |
245 | ||
246 | ex = *((struct exec *) bprm->buf); /* exec-header */ | |
247 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && | |
248 | N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || | |
249 | N_TRSIZE(ex) || N_DRSIZE(ex) || | |
0f7fc9e4 | 250 | i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
1da177e4 LT |
251 | return -ENOEXEC; |
252 | } | |
253 | ||
8454aeef ET |
254 | /* |
255 | * Requires a mmap handler. This prevents people from using a.out | |
256 | * as part of an exploit attack against /proc-related vulnerabilities. | |
257 | */ | |
258 | if (!bprm->file->f_op || !bprm->file->f_op->mmap) | |
259 | return -ENOEXEC; | |
260 | ||
1da177e4 LT |
261 | fd_offset = N_TXTOFF(ex); |
262 | ||
263 | /* Check initial limits. This avoids letting people circumvent | |
264 | * size limits imposed on them by creating programs with large | |
265 | * arrays in the data or bss. | |
266 | */ | |
d554ed89 | 267 | rlim = rlimit(RLIMIT_DATA); |
1da177e4 LT |
268 | if (rlim >= RLIM_INFINITY) |
269 | rlim = ~0; | |
270 | if (ex.a_data + ex.a_bss > rlim) | |
271 | return -ENOMEM; | |
272 | ||
273 | /* Flush all traces of the currently running executable */ | |
274 | retval = flush_old_exec(bprm); | |
275 | if (retval) | |
276 | return retval; | |
277 | ||
278 | /* OK, This is the point of no return */ | |
17580d7f | 279 | #ifdef __alpha__ |
1da177e4 | 280 | SET_AOUT_PERSONALITY(bprm, ex); |
1da177e4 LT |
281 | #else |
282 | set_personality(PER_LINUX); | |
283 | #endif | |
221af7f8 | 284 | setup_new_exec(bprm); |
1da177e4 LT |
285 | |
286 | current->mm->end_code = ex.a_text + | |
287 | (current->mm->start_code = N_TXTADDR(ex)); | |
288 | current->mm->end_data = ex.a_data + | |
289 | (current->mm->start_data = N_DATADDR(ex)); | |
290 | current->mm->brk = ex.a_bss + | |
291 | (current->mm->start_brk = N_BSSADDR(ex)); | |
292 | current->mm->free_area_cache = current->mm->mmap_base; | |
1363c3cd | 293 | current->mm->cached_hole_size = 0; |
1da177e4 | 294 | |
a6f76f23 | 295 | install_exec_creds(bprm); |
1da177e4 | 296 | current->flags &= ~PF_FORKNOEXEC; |
1da177e4 LT |
297 | |
298 | if (N_MAGIC(ex) == OMAGIC) { | |
299 | unsigned long text_addr, map_size; | |
300 | loff_t pos; | |
301 | ||
302 | text_addr = N_TXTADDR(ex); | |
303 | ||
fe30af97 | 304 | #ifdef __alpha__ |
1da177e4 LT |
305 | pos = fd_offset; |
306 | map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; | |
307 | #else | |
308 | pos = 32; | |
309 | map_size = ex.a_text+ex.a_data; | |
310 | #endif | |
311 | down_write(¤t->mm->mmap_sem); | |
312 | error = do_brk(text_addr & PAGE_MASK, map_size); | |
313 | up_write(¤t->mm->mmap_sem); | |
314 | if (error != (text_addr & PAGE_MASK)) { | |
315 | send_sig(SIGKILL, current, 0); | |
316 | return error; | |
317 | } | |
318 | ||
319 | error = bprm->file->f_op->read(bprm->file, | |
320 | (char __user *)text_addr, | |
321 | ex.a_text+ex.a_data, &pos); | |
322 | if ((signed long)error < 0) { | |
323 | send_sig(SIGKILL, current, 0); | |
324 | return error; | |
325 | } | |
326 | ||
327 | flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data); | |
328 | } else { | |
1da177e4 | 329 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
2e50b6cc | 330 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
1da177e4 LT |
331 | { |
332 | printk(KERN_NOTICE "executable not page aligned\n"); | |
1da177e4 LT |
333 | } |
334 | ||
2e50b6cc | 335 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
1da177e4 LT |
336 | { |
337 | printk(KERN_WARNING | |
338 | "fd_offset is not page aligned. Please convert program: %s\n", | |
0f7fc9e4 | 339 | bprm->file->f_path.dentry->d_name.name); |
1da177e4 LT |
340 | } |
341 | ||
342 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { | |
343 | loff_t pos = fd_offset; | |
344 | down_write(¤t->mm->mmap_sem); | |
345 | do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); | |
346 | up_write(¤t->mm->mmap_sem); | |
347 | bprm->file->f_op->read(bprm->file, | |
348 | (char __user *)N_TXTADDR(ex), | |
349 | ex.a_text+ex.a_data, &pos); | |
350 | flush_icache_range((unsigned long) N_TXTADDR(ex), | |
351 | (unsigned long) N_TXTADDR(ex) + | |
352 | ex.a_text+ex.a_data); | |
353 | goto beyond_if; | |
354 | } | |
355 | ||
356 | down_write(¤t->mm->mmap_sem); | |
357 | error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, | |
358 | PROT_READ | PROT_EXEC, | |
359 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, | |
360 | fd_offset); | |
361 | up_write(¤t->mm->mmap_sem); | |
362 | ||
363 | if (error != N_TXTADDR(ex)) { | |
364 | send_sig(SIGKILL, current, 0); | |
365 | return error; | |
366 | } | |
367 | ||
368 | down_write(¤t->mm->mmap_sem); | |
369 | error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data, | |
370 | PROT_READ | PROT_WRITE | PROT_EXEC, | |
371 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, | |
372 | fd_offset + ex.a_text); | |
373 | up_write(¤t->mm->mmap_sem); | |
374 | if (error != N_DATADDR(ex)) { | |
375 | send_sig(SIGKILL, current, 0); | |
376 | return error; | |
377 | } | |
378 | } | |
379 | beyond_if: | |
380 | set_binfmt(&aout_format); | |
381 | ||
382 | retval = set_brk(current->mm->start_brk, current->mm->brk); | |
383 | if (retval < 0) { | |
384 | send_sig(SIGKILL, current, 0); | |
385 | return retval; | |
386 | } | |
387 | ||
388 | retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); | |
389 | if (retval < 0) { | |
390 | /* Someone check-me: is this error path enough? */ | |
391 | send_sig(SIGKILL, current, 0); | |
392 | return retval; | |
393 | } | |
394 | ||
395 | current->mm->start_stack = | |
396 | (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); | |
397 | #ifdef __alpha__ | |
398 | regs->gp = ex.a_gpvalue; | |
399 | #endif | |
400 | start_thread(regs, ex.a_entry, current->mm->start_stack); | |
1da177e4 LT |
401 | return 0; |
402 | } | |
403 | ||
404 | static int load_aout_library(struct file *file) | |
405 | { | |
406 | struct inode * inode; | |
407 | unsigned long bss, start_addr, len; | |
408 | unsigned long error; | |
409 | int retval; | |
410 | struct exec ex; | |
411 | ||
0f7fc9e4 | 412 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
413 | |
414 | retval = -ENOEXEC; | |
415 | error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); | |
416 | if (error != sizeof(ex)) | |
417 | goto out; | |
418 | ||
419 | /* We come in here for the regular a.out style of shared libraries */ | |
420 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || | |
421 | N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || | |
422 | i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { | |
423 | goto out; | |
424 | } | |
425 | ||
8454aeef ET |
426 | /* |
427 | * Requires a mmap handler. This prevents people from using a.out | |
428 | * as part of an exploit attack against /proc-related vulnerabilities. | |
429 | */ | |
430 | if (!file->f_op || !file->f_op->mmap) | |
431 | goto out; | |
432 | ||
1da177e4 LT |
433 | if (N_FLAGS(ex)) |
434 | goto out; | |
435 | ||
436 | /* For QMAGIC, the starting address is 0x20 into the page. We mask | |
437 | this off to get the starting address for the page */ | |
438 | ||
439 | start_addr = ex.a_entry & 0xfffff000; | |
440 | ||
441 | if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { | |
1da177e4 LT |
442 | loff_t pos = N_TXTOFF(ex); |
443 | ||
2e50b6cc | 444 | if (printk_ratelimit()) |
1da177e4 LT |
445 | { |
446 | printk(KERN_WARNING | |
447 | "N_TXTOFF is not page aligned. Please convert library: %s\n", | |
0f7fc9e4 | 448 | file->f_path.dentry->d_name.name); |
1da177e4 LT |
449 | } |
450 | down_write(¤t->mm->mmap_sem); | |
451 | do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); | |
452 | up_write(¤t->mm->mmap_sem); | |
453 | ||
454 | file->f_op->read(file, (char __user *)start_addr, | |
455 | ex.a_text + ex.a_data, &pos); | |
456 | flush_icache_range((unsigned long) start_addr, | |
457 | (unsigned long) start_addr + ex.a_text + ex.a_data); | |
458 | ||
459 | retval = 0; | |
460 | goto out; | |
461 | } | |
462 | /* Now use mmap to map the library into memory. */ | |
463 | down_write(¤t->mm->mmap_sem); | |
464 | error = do_mmap(file, start_addr, ex.a_text + ex.a_data, | |
465 | PROT_READ | PROT_WRITE | PROT_EXEC, | |
466 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, | |
467 | N_TXTOFF(ex)); | |
468 | up_write(¤t->mm->mmap_sem); | |
469 | retval = error; | |
470 | if (error != start_addr) | |
471 | goto out; | |
472 | ||
473 | len = PAGE_ALIGN(ex.a_text + ex.a_data); | |
474 | bss = ex.a_text + ex.a_data + ex.a_bss; | |
475 | if (bss > len) { | |
476 | down_write(¤t->mm->mmap_sem); | |
477 | error = do_brk(start_addr + len, bss - len); | |
478 | up_write(¤t->mm->mmap_sem); | |
479 | retval = error; | |
480 | if (error != start_addr + len) | |
481 | goto out; | |
482 | } | |
483 | retval = 0; | |
484 | out: | |
485 | return retval; | |
486 | } | |
487 | ||
488 | static int __init init_aout_binfmt(void) | |
489 | { | |
490 | return register_binfmt(&aout_format); | |
491 | } | |
492 | ||
493 | static void __exit exit_aout_binfmt(void) | |
494 | { | |
495 | unregister_binfmt(&aout_format); | |
496 | } | |
497 | ||
498 | core_initcall(init_aout_binfmt); | |
499 | module_exit(exit_aout_binfmt); | |
500 | MODULE_LICENSE("GPL"); |