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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/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(¤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 | |
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 | void __user *dump_start; |
79 | int dump_size; |
80 | struct user dump; |
81 | #ifdef __alpha__ |
82 | # define START_DATA(u) ((void __user *)u.start_data) |
83 | #else |
84 | # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \ |
85 | u.start_code)) |
86 | #endif |
87 | # define START_STACK(u) ((void __user *)u.start_stack) |
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)); |
94 | dump.u_ar0 = offsetof(struct user, regs); |
95 | dump.signal = cprm->signr; |
96 | aout_dump_thread(cprm->regs, &dump); |
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. */ |
100 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
101 | dump.u_dsize = 0; |
102 | |
103 | /* Make sure we have enough room to write the stack and data areas. */ |
104 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
105 | dump.u_ssize = 0; |
106 | |
107 | /* make sure we actually have a data and stack area to dump */ |
108 | set_fs(USER_DS); |
109 | if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
110 | dump.u_dsize = 0; |
111 | if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) |
112 | dump.u_ssize = 0; |
113 | |
114 | set_fs(KERNEL_DS); |
115 | /* struct user */ |
116 | if (!dump_write(file, &dump, sizeof(dump))) |
117 | goto end_coredump; |
118 | /* Now dump all of the user data. Include malloced stuff as well */ |
119 | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
120 | goto end_coredump; |
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); |
126 | dump_size = dump.u_dsize << PAGE_SHIFT; |
127 | if (!dump_write(file, dump_start, dump_size)) |
128 | goto end_coredump; |
129 | } |
130 | /* Now prepare to dump the stack area */ |
131 | if (dump.u_ssize != 0) { |
132 | dump_start = START_STACK(dump); |
133 | dump_size = dump.u_ssize << PAGE_SHIFT; |
134 | if (!dump_write(file, dump_start, dump_size)) |
135 | goto end_coredump; |
136 | } |
137 | /* Finally dump the task struct. Not be used by gdb, but could be useful */ |
138 | set_fs(KERNEL_DS); |
139 | if (!dump_write(file, current, sizeof(*current))) |
140 | goto end_coredump; |
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); |
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); |
166 | put_user(1003, --sp); |
167 | put_user(bprm->loader, --sp); |
168 | put_user(1002, --sp); |
169 | } |
170 | put_user(bprm->exec, --sp); |
171 | put_user(1001, --sp); |
172 | #endif |
173 | sp -= envc+1; |
174 | envp = (char __user * __user *) sp; |
175 | sp -= argc+1; |
176 | argv = (char __user * __user *) sp; |
177 | #ifndef __alpha__ |
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) || |
221 | i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
222 | return -ENOEXEC; |
223 | } |
224 | |
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 | |
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 | */ |
238 | rlim = rlimit(RLIMIT_DATA); |
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 */ |
250 | #ifdef __alpha__ |
251 | SET_AOUT_PERSONALITY(bprm, ex); |
252 | #else |
253 | set_personality(PER_LINUX); |
254 | #endif |
255 | setup_new_exec(bprm); |
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; |
264 | current->mm->cached_hole_size = 0; |
265 | |
266 | install_exec_creds(bprm); |
267 | current->flags &= ~PF_FORKNOEXEC; |
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 | |
275 | #ifdef __alpha__ |
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 { |
300 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
301 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
302 | { |
303 | printk(KERN_NOTICE "executable not page aligned\n"); |
304 | } |
305 | |
306 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
307 | { |
308 | printk(KERN_WARNING |
309 | "fd_offset is not page aligned. Please convert program: %s\n", |
310 | bprm->file->f_path.dentry->d_name.name); |
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); |
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 | |
383 | inode = file->f_path.dentry->d_inode; |
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 | |
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 | |
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) { |
413 | loff_t pos = N_TXTOFF(ex); |
414 | |
415 | if (printk_ratelimit()) |
416 | { |
417 | printk(KERN_WARNING |
418 | "N_TXTOFF is not page aligned. Please convert library: %s\n", |
419 | file->f_path.dentry->d_name.name); |
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"); |
472 |
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