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> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/binfmts.h> | |
25 | #include <linux/personality.h> | |
26 | #include <linux/init.h> | |
088e7af7 | 27 | #include <linux/coredump.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; | |
78 | unsigned long dump_start, dump_size; | |
79 | struct user dump; | |
17580d7f | 80 | #ifdef __alpha__ |
1da177e4 | 81 | # define START_DATA(u) (u.start_data) |
17580d7f | 82 | #else |
1da177e4 | 83 | # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code) |
1da177e4 | 84 | #endif |
1da177e4 | 85 | # define START_STACK(u) (u.start_stack) |
1da177e4 LT |
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)); | |
6e16d89b | 92 | dump.u_ar0 = offsetof(struct user, regs); |
f6151dfe MH |
93 | dump.signal = cprm->signr; |
94 | aout_dump_thread(cprm->regs, &dump); | |
1da177e4 LT |
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. */ | |
f6151dfe | 98 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 99 | dump.u_dsize = 0; |
1da177e4 LT |
100 | |
101 | /* Make sure we have enough room to write the stack and data areas. */ | |
f6151dfe | 102 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
1da177e4 | 103 | dump.u_ssize = 0; |
1da177e4 LT |
104 | |
105 | /* make sure we actually have a data and stack area to dump */ | |
106 | set_fs(USER_DS); | |
1da177e4 LT |
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; | |
1da177e4 LT |
111 | |
112 | set_fs(KERNEL_DS); | |
113 | /* struct user */ | |
088e7af7 DH |
114 | if (!dump_write(file, &dump, sizeof(dump))) |
115 | goto end_coredump; | |
1da177e4 | 116 | /* Now dump all of the user data. Include malloced stuff as well */ |
05f47fda DH |
117 | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
118 | goto end_coredump; | |
1da177e4 LT |
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); | |
1da177e4 | 124 | dump_size = dump.u_dsize << PAGE_SHIFT; |
088e7af7 DH |
125 | if (!dump_write(file, dump_start, dump_size)) |
126 | goto end_coredump; | |
1da177e4 LT |
127 | } |
128 | /* Now prepare to dump the stack area */ | |
129 | if (dump.u_ssize != 0) { | |
130 | dump_start = START_STACK(dump); | |
1da177e4 | 131 | dump_size = dump.u_ssize << PAGE_SHIFT; |
088e7af7 DH |
132 | if (!dump_write(file, dump_start, dump_size)) |
133 | goto end_coredump; | |
1da177e4 LT |
134 | } |
135 | /* Finally dump the task struct. Not be used by gdb, but could be useful */ | |
136 | set_fs(KERNEL_DS); | |
088e7af7 DH |
137 | if (!dump_write(file, current, sizeof(*current))) |
138 | goto end_coredump; | |
1da177e4 LT |
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); | |
1da177e4 LT |
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); | |
17580d7f | 164 | put_user(1003, --sp); |
1da177e4 | 165 | put_user(bprm->loader, --sp); |
17580d7f | 166 | put_user(1002, --sp); |
1da177e4 LT |
167 | } |
168 | put_user(bprm->exec, --sp); | |
17580d7f | 169 | put_user(1001, --sp); |
1da177e4 LT |
170 | #endif |
171 | sp -= envc+1; | |
172 | envp = (char __user * __user *) sp; | |
173 | sp -= argc+1; | |
174 | argv = (char __user * __user *) sp; | |
17580d7f | 175 | #ifndef __alpha__ |
1da177e4 LT |
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) || | |
0f7fc9e4 | 219 | i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
1da177e4 LT |
220 | return -ENOEXEC; |
221 | } | |
222 | ||
8454aeef ET |
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 | ||
1da177e4 LT |
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 | */ | |
d554ed89 | 236 | rlim = rlimit(RLIMIT_DATA); |
1da177e4 LT |
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 */ | |
17580d7f | 248 | #ifdef __alpha__ |
1da177e4 | 249 | SET_AOUT_PERSONALITY(bprm, ex); |
1da177e4 LT |
250 | #else |
251 | set_personality(PER_LINUX); | |
252 | #endif | |
221af7f8 | 253 | setup_new_exec(bprm); |
1da177e4 LT |
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; | |
1363c3cd | 262 | current->mm->cached_hole_size = 0; |
1da177e4 | 263 | |
a6f76f23 | 264 | install_exec_creds(bprm); |
1da177e4 | 265 | current->flags &= ~PF_FORKNOEXEC; |
1da177e4 LT |
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 | ||
fe30af97 | 273 | #ifdef __alpha__ |
1da177e4 LT |
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(¤t->mm->mmap_sem); | |
281 | error = do_brk(text_addr & PAGE_MASK, map_size); | |
282 | up_write(¤t->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 { | |
1da177e4 | 298 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
2e50b6cc | 299 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
1da177e4 LT |
300 | { |
301 | printk(KERN_NOTICE "executable not page aligned\n"); | |
1da177e4 LT |
302 | } |
303 | ||
2e50b6cc | 304 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
1da177e4 LT |
305 | { |
306 | printk(KERN_WARNING | |
307 | "fd_offset is not page aligned. Please convert program: %s\n", | |
0f7fc9e4 | 308 | bprm->file->f_path.dentry->d_name.name); |
1da177e4 LT |
309 | } |
310 | ||
311 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { | |
312 | loff_t pos = fd_offset; | |
313 | down_write(¤t->mm->mmap_sem); | |
314 | do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); | |
315 | up_write(¤t->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(¤t->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(¤t->mm->mmap_sem); | |
331 | ||
332 | if (error != N_TXTADDR(ex)) { | |
333 | send_sig(SIGKILL, current, 0); | |
334 | return error; | |
335 | } | |
336 | ||
337 | down_write(¤t->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(¤t->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); | |
1da177e4 LT |
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 | ||
0f7fc9e4 | 381 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
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 | ||
8454aeef ET |
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 | ||
1da177e4 LT |
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) { | |
1da177e4 LT |
411 | loff_t pos = N_TXTOFF(ex); |
412 | ||
2e50b6cc | 413 | if (printk_ratelimit()) |
1da177e4 LT |
414 | { |
415 | printk(KERN_WARNING | |
416 | "N_TXTOFF is not page aligned. Please convert library: %s\n", | |
0f7fc9e4 | 417 | file->f_path.dentry->d_name.name); |
1da177e4 LT |
418 | } |
419 | down_write(¤t->mm->mmap_sem); | |
420 | do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); | |
421 | up_write(¤t->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(¤t->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(¤t->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(¤t->mm->mmap_sem); | |
446 | error = do_brk(start_addr + len, bss - len); | |
447 | up_write(¤t->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"); |