Commit | Line | Data |
---|---|---|
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> | |
1da177e4 LT |
23 | #include <linux/binfmts.h> |
24 | #include <linux/personality.h> | |
25 | #include <linux/init.h> | |
088e7af7 | 26 | #include <linux/coredump.h> |
5a0e3ad6 | 27 | #include <linux/slab.h> |
1da177e4 LT |
28 | |
29 | #include <asm/system.h> | |
30 | #include <asm/uaccess.h> | |
31 | #include <asm/cacheflush.h> | |
7fa30315 | 32 | #include <asm/a.out-core.h> |
1da177e4 LT |
33 | |
34 | static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); | |
35 | static int load_aout_library(struct file*); | |
f6151dfe | 36 | static int aout_core_dump(struct coredump_params *cprm); |
1da177e4 | 37 | |
1da177e4 LT |
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(¤t->mm->mmap_sem); | |
55 | addr = do_brk(start, end - start); | |
56 | up_write(¤t->mm->mmap_sem); | |
57 | if (BAD_ADDR(addr)) | |
58 | return addr; | |
59 | } | |
60 | return 0; | |
61 | } | |
62 | ||
1da177e4 LT |
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 | ||
f6151dfe | 73 | static int aout_core_dump(struct coredump_params *cprm) |
1da177e4 | 74 | { |
f6151dfe | 75 | struct file *file = cprm->file; |
1da177e4 LT |
76 | mm_segment_t fs; |
77 | int has_dumped = 0; | |
7731d9a5 BP |
78 | void __user *dump_start; |
79 | int dump_size; | |
1da177e4 | 80 | struct user dump; |
17580d7f | 81 | #ifdef __alpha__ |
7731d9a5 | 82 | # define START_DATA(u) ((void __user *)u.start_data) |
17580d7f | 83 | #else |
7731d9a5 BP |
84 | # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \ |
85 | u.start_code)) | |
1da177e4 | 86 | #endif |
7731d9a5 | 87 | # define START_STACK(u) ((void __user *)u.start_stack) |
1da177e4 LT |
88 | |
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)); | |
6e16d89b | 94 | dump.u_ar0 = offsetof(struct user, regs); |
f6151dfe MH |
95 | dump.signal = cprm->signr; |
96 | aout_dump_thread(cprm->regs, &dump); | |
1da177e4 LT |
97 | |
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. */ | |
f6151dfe | 100 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 101 | dump.u_dsize = 0; |
1da177e4 LT |
102 | |
103 | /* Make sure we have enough room to write the stack and data areas. */ | |
f6151dfe | 104 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 105 | dump.u_ssize = 0; |
1da177e4 LT |
106 | |
107 | /* make sure we actually have a data and stack area to dump */ | |
108 | set_fs(USER_DS); | |
7731d9a5 | 109 | if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
1da177e4 | 110 | dump.u_dsize = 0; |
7731d9a5 | 111 | if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) |
1da177e4 | 112 | dump.u_ssize = 0; |
1da177e4 LT |
113 | |
114 | set_fs(KERNEL_DS); | |
115 | /* struct user */ | |
088e7af7 DH |
116 | if (!dump_write(file, &dump, sizeof(dump))) |
117 | goto end_coredump; | |
1da177e4 | 118 | /* Now dump all of the user data. Include malloced stuff as well */ |
05f47fda DH |
119 | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
120 | goto end_coredump; | |
1da177e4 LT |
121 | /* 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); | |
1da177e4 | 126 | dump_size = dump.u_dsize << PAGE_SHIFT; |
088e7af7 DH |
127 | if (!dump_write(file, dump_start, dump_size)) |
128 | goto end_coredump; | |
1da177e4 LT |
129 | } |
130 | /* Now prepare to dump the stack area */ | |
131 | if (dump.u_ssize != 0) { | |
132 | dump_start = START_STACK(dump); | |
1da177e4 | 133 | dump_size = dump.u_ssize << PAGE_SHIFT; |
088e7af7 DH |
134 | if (!dump_write(file, dump_start, dump_size)) |
135 | goto end_coredump; | |
1da177e4 LT |
136 | } |
137 | /* Finally dump the task struct. Not be used by gdb, but could be useful */ | |
138 | set_fs(KERNEL_DS); | |
088e7af7 DH |
139 | if (!dump_write(file, current, sizeof(*current))) |
140 | goto end_coredump; | |
1da177e4 LT |
141 | end_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 | */ | |
151 | static 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); | |
1da177e4 LT |
160 | #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); | |
17580d7f | 166 | put_user(1003, --sp); |
1da177e4 | 167 | put_user(bprm->loader, --sp); |
17580d7f | 168 | put_user(1002, --sp); |
1da177e4 LT |
169 | } |
170 | put_user(bprm->exec, --sp); | |
17580d7f | 171 | put_user(1001, --sp); |
1da177e4 LT |
172 | #endif |
173 | sp -= envc+1; | |
174 | envp = (char __user * __user *) sp; | |
175 | sp -= argc+1; | |
176 | argv = (char __user * __user *) sp; | |
17580d7f | 177 | #ifndef __alpha__ |
1da177e4 LT |
178 | 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 | ||
209 | static 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) || | |
0f7fc9e4 | 221 | i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
1da177e4 LT |
222 | return -ENOEXEC; |
223 | } | |
224 | ||
8454aeef ET |
225 | /* |
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 | ||
1da177e4 LT |
232 | 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 | */ | |
d554ed89 | 238 | rlim = rlimit(RLIMIT_DATA); |
1da177e4 LT |
239 | 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 */ | |
17580d7f | 250 | #ifdef __alpha__ |
1da177e4 | 251 | SET_AOUT_PERSONALITY(bprm, ex); |
1da177e4 LT |
252 | #else |
253 | set_personality(PER_LINUX); | |
254 | #endif | |
221af7f8 | 255 | setup_new_exec(bprm); |
1da177e4 LT |
256 | |
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; | |
1363c3cd | 264 | current->mm->cached_hole_size = 0; |
1da177e4 | 265 | |
a6f76f23 | 266 | install_exec_creds(bprm); |
1da177e4 | 267 | current->flags &= ~PF_FORKNOEXEC; |
1da177e4 LT |
268 | |
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 | ||
fe30af97 | 275 | #ifdef __alpha__ |
1da177e4 LT |
276 | 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(¤t->mm->mmap_sem); | |
283 | error = do_brk(text_addr & PAGE_MASK, map_size); | |
284 | up_write(¤t->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 { | |
1da177e4 | 300 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
2e50b6cc | 301 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
1da177e4 LT |
302 | { |
303 | printk(KERN_NOTICE "executable not page aligned\n"); | |
1da177e4 LT |
304 | } |
305 | ||
2e50b6cc | 306 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
1da177e4 LT |
307 | { |
308 | printk(KERN_WARNING | |
309 | "fd_offset is not page aligned. Please convert program: %s\n", | |
0f7fc9e4 | 310 | bprm->file->f_path.dentry->d_name.name); |
1da177e4 LT |
311 | } |
312 | ||
313 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { | |
314 | loff_t pos = fd_offset; | |
315 | down_write(¤t->mm->mmap_sem); | |
316 | do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); | |
317 | up_write(¤t->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(¤t->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(¤t->mm->mmap_sem); | |
333 | ||
334 | if (error != N_TXTADDR(ex)) { | |
335 | send_sig(SIGKILL, current, 0); | |
336 | return error; | |
337 | } | |
338 | ||
339 | down_write(¤t->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(¤t->mm->mmap_sem); | |
345 | if (error != N_DATADDR(ex)) { | |
346 | send_sig(SIGKILL, current, 0); | |
347 | return error; | |
348 | } | |
349 | } | |
350 | beyond_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); | |
1da177e4 LT |
372 | return 0; |
373 | } | |
374 | ||
375 | static 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 | ||
0f7fc9e4 | 383 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
384 | |
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 | ||
8454aeef ET |
397 | /* |
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 | ||
1da177e4 LT |
404 | 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) { | |
1da177e4 LT |
413 | loff_t pos = N_TXTOFF(ex); |
414 | ||
2e50b6cc | 415 | if (printk_ratelimit()) |
1da177e4 LT |
416 | { |
417 | printk(KERN_WARNING | |
418 | "N_TXTOFF is not page aligned. Please convert library: %s\n", | |
0f7fc9e4 | 419 | file->f_path.dentry->d_name.name); |
1da177e4 LT |
420 | } |
421 | down_write(¤t->mm->mmap_sem); | |
422 | do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); | |
423 | up_write(¤t->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(¤t->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(¤t->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(¤t->mm->mmap_sem); | |
448 | error = do_brk(start_addr + len, bss - len); | |
449 | up_write(¤t->mm->mmap_sem); | |
450 | retval = error; | |
451 | if (error != start_addr + len) | |
452 | goto out; | |
453 | } | |
454 | retval = 0; | |
455 | out: | |
456 | return retval; | |
457 | } | |
458 | ||
459 | static int __init init_aout_binfmt(void) | |
460 | { | |
461 | return register_binfmt(&aout_format); | |
462 | } | |
463 | ||
464 | static void __exit exit_aout_binfmt(void) | |
465 | { | |
466 | unregister_binfmt(&aout_format); | |
467 | } | |
468 | ||
469 | core_initcall(init_aout_binfmt); | |
470 | module_exit(exit_aout_binfmt); | |
471 | MODULE_LICENSE("GPL"); |