blob: ae1b5404fced41881247e59073cb6fb6c31222a1
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 *); |
34 | static int load_aout_library(struct file*); |
35 | |
36 | #ifdef CONFIG_COREDUMP |
37 | /* |
38 | * Routine writes a core dump image in the current directory. |
39 | * Currently only a stub-function. |
40 | * |
41 | * Note that setuid/setgid files won't make a core-dump if the uid/gid |
42 | * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" |
43 | * field, which also makes sure the core-dumps won't be recursive if the |
44 | * dumping of the process results in another error.. |
45 | */ |
46 | static int aout_core_dump(struct coredump_params *cprm) |
47 | { |
48 | mm_segment_t fs; |
49 | int has_dumped = 0; |
50 | void __user *dump_start; |
51 | int dump_size; |
52 | struct user dump; |
53 | #ifdef __alpha__ |
54 | # define START_DATA(u) ((void __user *)u.start_data) |
55 | #else |
56 | # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \ |
57 | u.start_code)) |
58 | #endif |
59 | # define START_STACK(u) ((void __user *)u.start_stack) |
60 | |
61 | fs = get_fs(); |
62 | set_fs(KERNEL_DS); |
63 | has_dumped = 1; |
64 | strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); |
65 | dump.u_ar0 = offsetof(struct user, regs); |
66 | dump.signal = cprm->siginfo->si_signo; |
67 | aout_dump_thread(cprm->regs, &dump); |
68 | |
69 | /* If the size of the dump file exceeds the rlimit, then see what would happen |
70 | if we wrote the stack, but not the data area. */ |
71 | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
72 | dump.u_dsize = 0; |
73 | |
74 | /* Make sure we have enough room to write the stack and data areas. */ |
75 | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
76 | dump.u_ssize = 0; |
77 | |
78 | /* make sure we actually have a data and stack area to dump */ |
79 | set_fs(USER_DS); |
80 | if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
81 | dump.u_dsize = 0; |
82 | if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) |
83 | dump.u_ssize = 0; |
84 | |
85 | set_fs(KERNEL_DS); |
86 | /* struct user */ |
87 | if (!dump_emit(cprm, &dump, sizeof(dump))) |
88 | goto end_coredump; |
89 | /* Now dump all of the user data. Include malloced stuff as well */ |
90 | if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump))) |
91 | goto end_coredump; |
92 | /* now we start writing out the user space info */ |
93 | set_fs(USER_DS); |
94 | /* Dump the data area */ |
95 | if (dump.u_dsize != 0) { |
96 | dump_start = START_DATA(dump); |
97 | dump_size = dump.u_dsize << PAGE_SHIFT; |
98 | if (!dump_emit(cprm, dump_start, dump_size)) |
99 | goto end_coredump; |
100 | } |
101 | /* Now prepare to dump the stack area */ |
102 | if (dump.u_ssize != 0) { |
103 | dump_start = START_STACK(dump); |
104 | dump_size = dump.u_ssize << PAGE_SHIFT; |
105 | if (!dump_emit(cprm, dump_start, dump_size)) |
106 | goto end_coredump; |
107 | } |
108 | end_coredump: |
109 | set_fs(fs); |
110 | return has_dumped; |
111 | } |
112 | #else |
113 | #define aout_core_dump NULL |
114 | #endif |
115 | |
116 | static struct linux_binfmt aout_format = { |
117 | .module = THIS_MODULE, |
118 | .load_binary = load_aout_binary, |
119 | .load_shlib = load_aout_library, |
120 | .core_dump = aout_core_dump, |
121 | .min_coredump = PAGE_SIZE |
122 | }; |
123 | |
124 | #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE) |
125 | |
126 | static int set_brk(unsigned long start, unsigned long end) |
127 | { |
128 | start = PAGE_ALIGN(start); |
129 | end = PAGE_ALIGN(end); |
130 | if (end > start) |
131 | return vm_brk(start, end - start); |
132 | return 0; |
133 | } |
134 | |
135 | /* |
136 | * create_aout_tables() parses the env- and arg-strings in new user |
137 | * memory and creates the pointer tables from them, and puts their |
138 | * addresses on the "stack", returning the new stack pointer value. |
139 | */ |
140 | static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) |
141 | { |
142 | char __user * __user *argv; |
143 | char __user * __user *envp; |
144 | unsigned long __user *sp; |
145 | int argc = bprm->argc; |
146 | int envc = bprm->envc; |
147 | |
148 | sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); |
149 | #ifdef __alpha__ |
150 | /* whee.. test-programs are so much fun. */ |
151 | put_user(0, --sp); |
152 | put_user(0, --sp); |
153 | if (bprm->loader) { |
154 | put_user(0, --sp); |
155 | put_user(1003, --sp); |
156 | put_user(bprm->loader, --sp); |
157 | put_user(1002, --sp); |
158 | } |
159 | put_user(bprm->exec, --sp); |
160 | put_user(1001, --sp); |
161 | #endif |
162 | sp -= envc+1; |
163 | envp = (char __user * __user *) sp; |
164 | sp -= argc+1; |
165 | argv = (char __user * __user *) sp; |
166 | #ifndef __alpha__ |
167 | put_user((unsigned long) envp,--sp); |
168 | put_user((unsigned long) argv,--sp); |
169 | #endif |
170 | put_user(argc,--sp); |
171 | current->mm->arg_start = (unsigned long) p; |
172 | while (argc-->0) { |
173 | char c; |
174 | put_user(p,argv++); |
175 | do { |
176 | get_user(c,p++); |
177 | } while (c); |
178 | } |
179 | put_user(NULL,argv); |
180 | current->mm->arg_end = current->mm->env_start = (unsigned long) p; |
181 | while (envc-->0) { |
182 | char c; |
183 | put_user(p,envp++); |
184 | do { |
185 | get_user(c,p++); |
186 | } while (c); |
187 | } |
188 | put_user(NULL,envp); |
189 | current->mm->env_end = (unsigned long) p; |
190 | return sp; |
191 | } |
192 | |
193 | /* |
194 | * These are the functions used to load a.out style executables and shared |
195 | * libraries. There is no binary dependent code anywhere else. |
196 | */ |
197 | |
198 | static int load_aout_binary(struct linux_binprm * bprm) |
199 | { |
200 | struct pt_regs *regs = current_pt_regs(); |
201 | struct exec ex; |
202 | unsigned long error; |
203 | unsigned long fd_offset; |
204 | unsigned long rlim; |
205 | int retval; |
206 | |
207 | ex = *((struct exec *) bprm->buf); /* exec-header */ |
208 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && |
209 | N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || |
210 | N_TRSIZE(ex) || N_DRSIZE(ex) || |
211 | i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
212 | return -ENOEXEC; |
213 | } |
214 | |
215 | /* |
216 | * Requires a mmap handler. This prevents people from using a.out |
217 | * as part of an exploit attack against /proc-related vulnerabilities. |
218 | */ |
219 | if (!bprm->file->f_op->mmap) |
220 | return -ENOEXEC; |
221 | |
222 | fd_offset = N_TXTOFF(ex); |
223 | |
224 | /* Check initial limits. This avoids letting people circumvent |
225 | * size limits imposed on them by creating programs with large |
226 | * arrays in the data or bss. |
227 | */ |
228 | rlim = rlimit(RLIMIT_DATA); |
229 | if (rlim >= RLIM_INFINITY) |
230 | rlim = ~0; |
231 | if (ex.a_data + ex.a_bss > rlim) |
232 | return -ENOMEM; |
233 | |
234 | /* Flush all traces of the currently running executable */ |
235 | retval = flush_old_exec(bprm); |
236 | if (retval) |
237 | return retval; |
238 | |
239 | /* OK, This is the point of no return */ |
240 | #ifdef __alpha__ |
241 | SET_AOUT_PERSONALITY(bprm, ex); |
242 | #else |
243 | set_personality(PER_LINUX); |
244 | #endif |
245 | setup_new_exec(bprm); |
246 | |
247 | current->mm->end_code = ex.a_text + |
248 | (current->mm->start_code = N_TXTADDR(ex)); |
249 | current->mm->end_data = ex.a_data + |
250 | (current->mm->start_data = N_DATADDR(ex)); |
251 | current->mm->brk = ex.a_bss + |
252 | (current->mm->start_brk = N_BSSADDR(ex)); |
253 | |
254 | retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); |
255 | if (retval < 0) |
256 | return retval; |
257 | |
258 | install_exec_creds(bprm); |
259 | |
260 | if (N_MAGIC(ex) == OMAGIC) { |
261 | unsigned long text_addr, map_size; |
262 | loff_t pos; |
263 | |
264 | text_addr = N_TXTADDR(ex); |
265 | |
266 | #ifdef __alpha__ |
267 | pos = fd_offset; |
268 | map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; |
269 | #else |
270 | pos = 32; |
271 | map_size = ex.a_text+ex.a_data; |
272 | #endif |
273 | error = vm_brk(text_addr & PAGE_MASK, map_size); |
274 | if (error) |
275 | return error; |
276 | |
277 | error = read_code(bprm->file, text_addr, pos, |
278 | ex.a_text+ex.a_data); |
279 | if ((signed long)error < 0) |
280 | return error; |
281 | } else { |
282 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
283 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
284 | { |
285 | printk(KERN_NOTICE "executable not page aligned\n"); |
286 | } |
287 | |
288 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
289 | { |
290 | printk(KERN_WARNING |
291 | "fd_offset is not page aligned. Please convert program: %pD\n", |
292 | bprm->file); |
293 | } |
294 | |
295 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { |
296 | error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); |
297 | if (error) |
298 | return error; |
299 | |
300 | read_code(bprm->file, N_TXTADDR(ex), fd_offset, |
301 | ex.a_text + ex.a_data); |
302 | goto beyond_if; |
303 | } |
304 | |
305 | error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, |
306 | PROT_READ | PROT_EXEC, |
307 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
308 | fd_offset); |
309 | |
310 | if (error != N_TXTADDR(ex)) |
311 | return error; |
312 | |
313 | error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, |
314 | PROT_READ | PROT_WRITE | PROT_EXEC, |
315 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
316 | fd_offset + ex.a_text); |
317 | if (error != N_DATADDR(ex)) |
318 | return error; |
319 | } |
320 | beyond_if: |
321 | set_binfmt(&aout_format); |
322 | |
323 | retval = set_brk(current->mm->start_brk, current->mm->brk); |
324 | if (retval < 0) |
325 | return retval; |
326 | |
327 | current->mm->start_stack = |
328 | (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); |
329 | #ifdef __alpha__ |
330 | regs->gp = ex.a_gpvalue; |
331 | #endif |
332 | start_thread(regs, ex.a_entry, current->mm->start_stack); |
333 | return 0; |
334 | } |
335 | |
336 | static int load_aout_library(struct file *file) |
337 | { |
338 | struct inode * inode; |
339 | unsigned long bss, start_addr, len; |
340 | unsigned long error; |
341 | int retval; |
342 | struct exec ex; |
343 | |
344 | inode = file_inode(file); |
345 | |
346 | retval = -ENOEXEC; |
347 | error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); |
348 | if (error != sizeof(ex)) |
349 | goto out; |
350 | |
351 | /* We come in here for the regular a.out style of shared libraries */ |
352 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || |
353 | N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || |
354 | i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
355 | goto out; |
356 | } |
357 | |
358 | /* |
359 | * Requires a mmap handler. This prevents people from using a.out |
360 | * as part of an exploit attack against /proc-related vulnerabilities. |
361 | */ |
362 | if (!file->f_op->mmap) |
363 | goto out; |
364 | |
365 | if (N_FLAGS(ex)) |
366 | goto out; |
367 | |
368 | /* For QMAGIC, the starting address is 0x20 into the page. We mask |
369 | this off to get the starting address for the page */ |
370 | |
371 | start_addr = ex.a_entry & 0xfffff000; |
372 | |
373 | if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { |
374 | if (printk_ratelimit()) |
375 | { |
376 | printk(KERN_WARNING |
377 | "N_TXTOFF is not page aligned. Please convert library: %pD\n", |
378 | file); |
379 | } |
380 | retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); |
381 | if (retval) |
382 | goto out; |
383 | |
384 | read_code(file, start_addr, N_TXTOFF(ex), |
385 | ex.a_text + ex.a_data); |
386 | retval = 0; |
387 | goto out; |
388 | } |
389 | /* Now use mmap to map the library into memory. */ |
390 | error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, |
391 | PROT_READ | PROT_WRITE | PROT_EXEC, |
392 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, |
393 | N_TXTOFF(ex)); |
394 | retval = error; |
395 | if (error != start_addr) |
396 | goto out; |
397 | |
398 | len = PAGE_ALIGN(ex.a_text + ex.a_data); |
399 | bss = ex.a_text + ex.a_data + ex.a_bss; |
400 | if (bss > len) { |
401 | retval = vm_brk(start_addr + len, bss - len); |
402 | if (retval) |
403 | goto out; |
404 | } |
405 | retval = 0; |
406 | out: |
407 | return retval; |
408 | } |
409 | |
410 | static int __init init_aout_binfmt(void) |
411 | { |
412 | register_binfmt(&aout_format); |
413 | return 0; |
414 | } |
415 | |
416 | static void __exit exit_aout_binfmt(void) |
417 | { |
418 | unregister_binfmt(&aout_format); |
419 | } |
420 | |
421 | core_initcall(init_aout_binfmt); |
422 | module_exit(exit_aout_binfmt); |
423 | MODULE_LICENSE("GPL"); |
424 |