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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/uaccess.h> |
30 | #include <asm/cacheflush.h> |
31 | #include <asm/a.out-core.h> |
32 | |
33 | static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); |
34 | static int load_aout_library(struct file*); |
35 | static int aout_core_dump(struct coredump_params *cprm); |
36 | |
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 | addr = vm_brk(start, end - start); |
54 | if (BAD_ADDR(addr)) |
55 | return addr; |
56 | } |
57 | return 0; |
58 | } |
59 | |
60 | /* |
61 | * Routine writes a core dump image in the current directory. |
62 | * Currently only a stub-function. |
63 | * |
64 | * Note that setuid/setgid files won't make a core-dump if the uid/gid |
65 | * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" |
66 | * field, which also makes sure the core-dumps won't be recursive if the |
67 | * dumping of the process results in another error.. |
68 | */ |
69 | |
70 | static int aout_core_dump(struct coredump_params *cprm) |
71 | { |
72 | struct file *file = cprm->file; |
73 | mm_segment_t fs; |
74 | int has_dumped = 0; |
75 | void __user *dump_start; |
76 | int dump_size; |
77 | struct user dump; |
78 | #ifdef __alpha__ |
79 | # define START_DATA(u) ((void __user *)u.start_data) |
80 | #else |
81 | # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \ |
82 | u.start_code)) |
83 | #endif |
84 | # define START_STACK(u) ((void __user *)u.start_stack) |
85 | |
86 | fs = get_fs(); |
87 | set_fs(KERNEL_DS); |
88 | has_dumped = 1; |
89 | current->flags |= PF_DUMPCORE; |
90 | strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); |
91 | dump.u_ar0 = offsetof(struct user, regs); |
92 | dump.signal = cprm->signr; |
93 | aout_dump_thread(cprm->regs, &dump); |
94 | |
95 | /* If the size of the dump file exceeds the rlimit, then see what would happen |
96 | if we wrote the stack, but not the data area. */ |
97 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
98 | dump.u_dsize = 0; |
99 | |
100 | /* Make sure we have enough room to write the stack and data areas. */ |
101 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
102 | dump.u_ssize = 0; |
103 | |
104 | /* make sure we actually have a data and stack area to dump */ |
105 | set_fs(USER_DS); |
106 | if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
107 | dump.u_dsize = 0; |
108 | if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) |
109 | dump.u_ssize = 0; |
110 | |
111 | set_fs(KERNEL_DS); |
112 | /* struct user */ |
113 | if (!dump_write(file, &dump, sizeof(dump))) |
114 | goto end_coredump; |
115 | /* Now dump all of the user data. Include malloced stuff as well */ |
116 | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
117 | goto end_coredump; |
118 | /* now we start writing out the user space info */ |
119 | set_fs(USER_DS); |
120 | /* Dump the data area */ |
121 | if (dump.u_dsize != 0) { |
122 | dump_start = START_DATA(dump); |
123 | dump_size = dump.u_dsize << PAGE_SHIFT; |
124 | if (!dump_write(file, dump_start, dump_size)) |
125 | goto end_coredump; |
126 | } |
127 | /* Now prepare to dump the stack area */ |
128 | if (dump.u_ssize != 0) { |
129 | dump_start = START_STACK(dump); |
130 | dump_size = dump.u_ssize << PAGE_SHIFT; |
131 | if (!dump_write(file, dump_start, dump_size)) |
132 | goto end_coredump; |
133 | } |
134 | end_coredump: |
135 | set_fs(fs); |
136 | return has_dumped; |
137 | } |
138 | |
139 | /* |
140 | * create_aout_tables() parses the env- and arg-strings in new user |
141 | * memory and creates the pointer tables from them, and puts their |
142 | * addresses on the "stack", returning the new stack pointer value. |
143 | */ |
144 | static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) |
145 | { |
146 | char __user * __user *argv; |
147 | char __user * __user *envp; |
148 | unsigned long __user *sp; |
149 | int argc = bprm->argc; |
150 | int envc = bprm->envc; |
151 | |
152 | sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); |
153 | #ifdef __alpha__ |
154 | /* whee.. test-programs are so much fun. */ |
155 | put_user(0, --sp); |
156 | put_user(0, --sp); |
157 | if (bprm->loader) { |
158 | put_user(0, --sp); |
159 | put_user(1003, --sp); |
160 | put_user(bprm->loader, --sp); |
161 | put_user(1002, --sp); |
162 | } |
163 | put_user(bprm->exec, --sp); |
164 | put_user(1001, --sp); |
165 | #endif |
166 | sp -= envc+1; |
167 | envp = (char __user * __user *) sp; |
168 | sp -= argc+1; |
169 | argv = (char __user * __user *) sp; |
170 | #ifndef __alpha__ |
171 | put_user((unsigned long) envp,--sp); |
172 | put_user((unsigned long) argv,--sp); |
173 | #endif |
174 | put_user(argc,--sp); |
175 | current->mm->arg_start = (unsigned long) p; |
176 | while (argc-->0) { |
177 | char c; |
178 | put_user(p,argv++); |
179 | do { |
180 | get_user(c,p++); |
181 | } while (c); |
182 | } |
183 | put_user(NULL,argv); |
184 | current->mm->arg_end = current->mm->env_start = (unsigned long) p; |
185 | while (envc-->0) { |
186 | char c; |
187 | put_user(p,envp++); |
188 | do { |
189 | get_user(c,p++); |
190 | } while (c); |
191 | } |
192 | put_user(NULL,envp); |
193 | current->mm->env_end = (unsigned long) p; |
194 | return sp; |
195 | } |
196 | |
197 | /* |
198 | * These are the functions used to load a.out style executables and shared |
199 | * libraries. There is no binary dependent code anywhere else. |
200 | */ |
201 | |
202 | static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs) |
203 | { |
204 | struct exec ex; |
205 | unsigned long error; |
206 | unsigned long fd_offset; |
207 | unsigned long rlim; |
208 | int retval; |
209 | |
210 | ex = *((struct exec *) bprm->buf); /* exec-header */ |
211 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && |
212 | N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || |
213 | N_TRSIZE(ex) || N_DRSIZE(ex) || |
214 | i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
215 | return -ENOEXEC; |
216 | } |
217 | |
218 | /* |
219 | * Requires a mmap handler. This prevents people from using a.out |
220 | * as part of an exploit attack against /proc-related vulnerabilities. |
221 | */ |
222 | if (!bprm->file->f_op || !bprm->file->f_op->mmap) |
223 | return -ENOEXEC; |
224 | |
225 | fd_offset = N_TXTOFF(ex); |
226 | |
227 | /* Check initial limits. This avoids letting people circumvent |
228 | * size limits imposed on them by creating programs with large |
229 | * arrays in the data or bss. |
230 | */ |
231 | rlim = rlimit(RLIMIT_DATA); |
232 | if (rlim >= RLIM_INFINITY) |
233 | rlim = ~0; |
234 | if (ex.a_data + ex.a_bss > rlim) |
235 | return -ENOMEM; |
236 | |
237 | /* Flush all traces of the currently running executable */ |
238 | retval = flush_old_exec(bprm); |
239 | if (retval) |
240 | return retval; |
241 | |
242 | /* OK, This is the point of no return */ |
243 | #ifdef __alpha__ |
244 | SET_AOUT_PERSONALITY(bprm, ex); |
245 | #else |
246 | set_personality(PER_LINUX); |
247 | #endif |
248 | setup_new_exec(bprm); |
249 | |
250 | current->mm->end_code = ex.a_text + |
251 | (current->mm->start_code = N_TXTADDR(ex)); |
252 | current->mm->end_data = ex.a_data + |
253 | (current->mm->start_data = N_DATADDR(ex)); |
254 | current->mm->brk = ex.a_bss + |
255 | (current->mm->start_brk = N_BSSADDR(ex)); |
256 | current->mm->free_area_cache = current->mm->mmap_base; |
257 | current->mm->cached_hole_size = 0; |
258 | |
259 | retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); |
260 | if (retval < 0) { |
261 | /* Someone check-me: is this error path enough? */ |
262 | send_sig(SIGKILL, current, 0); |
263 | return retval; |
264 | } |
265 | |
266 | install_exec_creds(bprm); |
267 | |
268 | if (N_MAGIC(ex) == OMAGIC) { |
269 | unsigned long text_addr, map_size; |
270 | loff_t pos; |
271 | |
272 | text_addr = N_TXTADDR(ex); |
273 | |
274 | #ifdef __alpha__ |
275 | pos = fd_offset; |
276 | map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; |
277 | #else |
278 | pos = 32; |
279 | map_size = ex.a_text+ex.a_data; |
280 | #endif |
281 | error = vm_brk(text_addr & PAGE_MASK, map_size); |
282 | if (error != (text_addr & PAGE_MASK)) { |
283 | send_sig(SIGKILL, current, 0); |
284 | return error; |
285 | } |
286 | |
287 | error = bprm->file->f_op->read(bprm->file, |
288 | (char __user *)text_addr, |
289 | ex.a_text+ex.a_data, &pos); |
290 | if ((signed long)error < 0) { |
291 | send_sig(SIGKILL, current, 0); |
292 | return error; |
293 | } |
294 | |
295 | flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data); |
296 | } else { |
297 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
298 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
299 | { |
300 | printk(KERN_NOTICE "executable not page aligned\n"); |
301 | } |
302 | |
303 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
304 | { |
305 | printk(KERN_WARNING |
306 | "fd_offset is not page aligned. Please convert program: %s\n", |
307 | bprm->file->f_path.dentry->d_name.name); |
308 | } |
309 | |
310 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { |
311 | loff_t pos = fd_offset; |
312 | vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); |
313 | bprm->file->f_op->read(bprm->file, |
314 | (char __user *)N_TXTADDR(ex), |
315 | ex.a_text+ex.a_data, &pos); |
316 | flush_icache_range((unsigned long) N_TXTADDR(ex), |
317 | (unsigned long) N_TXTADDR(ex) + |
318 | ex.a_text+ex.a_data); |
319 | goto beyond_if; |
320 | } |
321 | |
322 | error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, |
323 | PROT_READ | PROT_EXEC, |
324 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
325 | fd_offset); |
326 | |
327 | if (error != N_TXTADDR(ex)) { |
328 | send_sig(SIGKILL, current, 0); |
329 | return error; |
330 | } |
331 | |
332 | error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, |
333 | PROT_READ | PROT_WRITE | PROT_EXEC, |
334 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
335 | fd_offset + ex.a_text); |
336 | if (error != N_DATADDR(ex)) { |
337 | send_sig(SIGKILL, current, 0); |
338 | return error; |
339 | } |
340 | } |
341 | beyond_if: |
342 | set_binfmt(&aout_format); |
343 | |
344 | retval = set_brk(current->mm->start_brk, current->mm->brk); |
345 | if (retval < 0) { |
346 | send_sig(SIGKILL, current, 0); |
347 | return retval; |
348 | } |
349 | |
350 | current->mm->start_stack = |
351 | (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); |
352 | #ifdef __alpha__ |
353 | regs->gp = ex.a_gpvalue; |
354 | #endif |
355 | start_thread(regs, ex.a_entry, current->mm->start_stack); |
356 | return 0; |
357 | } |
358 | |
359 | static int load_aout_library(struct file *file) |
360 | { |
361 | struct inode * inode; |
362 | unsigned long bss, start_addr, len; |
363 | unsigned long error; |
364 | int retval; |
365 | struct exec ex; |
366 | |
367 | inode = file->f_path.dentry->d_inode; |
368 | |
369 | retval = -ENOEXEC; |
370 | error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); |
371 | if (error != sizeof(ex)) |
372 | goto out; |
373 | |
374 | /* We come in here for the regular a.out style of shared libraries */ |
375 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || |
376 | N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || |
377 | i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
378 | goto out; |
379 | } |
380 | |
381 | /* |
382 | * Requires a mmap handler. This prevents people from using a.out |
383 | * as part of an exploit attack against /proc-related vulnerabilities. |
384 | */ |
385 | if (!file->f_op || !file->f_op->mmap) |
386 | goto out; |
387 | |
388 | if (N_FLAGS(ex)) |
389 | goto out; |
390 | |
391 | /* For QMAGIC, the starting address is 0x20 into the page. We mask |
392 | this off to get the starting address for the page */ |
393 | |
394 | start_addr = ex.a_entry & 0xfffff000; |
395 | |
396 | if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { |
397 | loff_t pos = N_TXTOFF(ex); |
398 | |
399 | if (printk_ratelimit()) |
400 | { |
401 | printk(KERN_WARNING |
402 | "N_TXTOFF is not page aligned. Please convert library: %s\n", |
403 | file->f_path.dentry->d_name.name); |
404 | } |
405 | vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); |
406 | |
407 | file->f_op->read(file, (char __user *)start_addr, |
408 | ex.a_text + ex.a_data, &pos); |
409 | flush_icache_range((unsigned long) start_addr, |
410 | (unsigned long) start_addr + ex.a_text + ex.a_data); |
411 | |
412 | retval = 0; |
413 | goto out; |
414 | } |
415 | /* Now use mmap to map the library into memory. */ |
416 | error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, |
417 | PROT_READ | PROT_WRITE | PROT_EXEC, |
418 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, |
419 | N_TXTOFF(ex)); |
420 | retval = error; |
421 | if (error != start_addr) |
422 | goto out; |
423 | |
424 | len = PAGE_ALIGN(ex.a_text + ex.a_data); |
425 | bss = ex.a_text + ex.a_data + ex.a_bss; |
426 | if (bss > len) { |
427 | error = vm_brk(start_addr + len, bss - len); |
428 | retval = error; |
429 | if (error != start_addr + len) |
430 | goto out; |
431 | } |
432 | retval = 0; |
433 | out: |
434 | return retval; |
435 | } |
436 | |
437 | static int __init init_aout_binfmt(void) |
438 | { |
439 | register_binfmt(&aout_format); |
440 | return 0; |
441 | } |
442 | |
443 | static void __exit exit_aout_binfmt(void) |
444 | { |
445 | unregister_binfmt(&aout_format); |
446 | } |
447 | |
448 | core_initcall(init_aout_binfmt); |
449 | module_exit(exit_aout_binfmt); |
450 | MODULE_LICENSE("GPL"); |
451 |
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