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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 *); | |
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 | unsigned long addr; | |
132 | addr = vm_brk(start, end - start); | |
133 | if (BAD_ADDR(addr)) | |
134 | return addr; | |
135 | } | |
136 | return 0; | |
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) | |
203 | { | |
204 | struct pt_regs *regs = current_pt_regs(); | |
205 | struct exec ex; | |
206 | unsigned long error; | |
207 | unsigned long fd_offset; | |
208 | unsigned long rlim; | |
209 | int retval; | |
210 | ||
211 | ex = *((struct exec *) bprm->buf); /* exec-header */ | |
212 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && | |
213 | N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || | |
214 | N_TRSIZE(ex) || N_DRSIZE(ex) || | |
215 | i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { | |
216 | return -ENOEXEC; | |
217 | } | |
218 | ||
219 | /* | |
220 | * Requires a mmap handler. This prevents people from using a.out | |
221 | * as part of an exploit attack against /proc-related vulnerabilities. | |
222 | */ | |
223 | if (!bprm->file->f_op->mmap) | |
224 | return -ENOEXEC; | |
225 | ||
226 | fd_offset = N_TXTOFF(ex); | |
227 | ||
228 | /* Check initial limits. This avoids letting people circumvent | |
229 | * size limits imposed on them by creating programs with large | |
230 | * arrays in the data or bss. | |
231 | */ | |
232 | rlim = rlimit(RLIMIT_DATA); | |
233 | if (rlim >= RLIM_INFINITY) | |
234 | rlim = ~0; | |
235 | if (ex.a_data + ex.a_bss > rlim) | |
236 | return -ENOMEM; | |
237 | ||
238 | /* Flush all traces of the currently running executable */ | |
239 | retval = flush_old_exec(bprm); | |
240 | if (retval) | |
241 | return retval; | |
242 | ||
243 | /* OK, This is the point of no return */ | |
244 | #ifdef __alpha__ | |
245 | SET_AOUT_PERSONALITY(bprm, ex); | |
246 | #else | |
247 | set_personality(PER_LINUX); | |
248 | #endif | |
249 | setup_new_exec(bprm); | |
250 | ||
251 | current->mm->end_code = ex.a_text + | |
252 | (current->mm->start_code = N_TXTADDR(ex)); | |
253 | current->mm->end_data = ex.a_data + | |
254 | (current->mm->start_data = N_DATADDR(ex)); | |
255 | current->mm->brk = ex.a_bss + | |
256 | (current->mm->start_brk = N_BSSADDR(ex)); | |
257 | ||
258 | retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); | |
259 | if (retval < 0) | |
260 | return retval; | |
261 | ||
262 | install_exec_creds(bprm); | |
263 | ||
264 | if (N_MAGIC(ex) == OMAGIC) { | |
265 | unsigned long text_addr, map_size; | |
266 | loff_t pos; | |
267 | ||
268 | text_addr = N_TXTADDR(ex); | |
269 | ||
270 | #ifdef __alpha__ | |
271 | pos = fd_offset; | |
272 | map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; | |
273 | #else | |
274 | pos = 32; | |
275 | map_size = ex.a_text+ex.a_data; | |
276 | #endif | |
277 | error = vm_brk(text_addr & PAGE_MASK, map_size); | |
278 | if (error != (text_addr & PAGE_MASK)) | |
279 | return error; | |
280 | ||
281 | error = read_code(bprm->file, text_addr, pos, | |
282 | ex.a_text+ex.a_data); | |
283 | if ((signed long)error < 0) | |
284 | return error; | |
285 | } else { | |
286 | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && | |
287 | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) | |
288 | { | |
289 | printk(KERN_NOTICE "executable not page aligned\n"); | |
290 | } | |
291 | ||
292 | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) | |
293 | { | |
294 | printk(KERN_WARNING | |
295 | "fd_offset is not page aligned. Please convert program: %pD\n", | |
296 | bprm->file); | |
297 | } | |
298 | ||
299 | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { | |
300 | vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); | |
301 | read_code(bprm->file, N_TXTADDR(ex), fd_offset, | |
302 | ex.a_text + ex.a_data); | |
303 | goto beyond_if; | |
304 | } | |
305 | ||
306 | error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, | |
307 | PROT_READ | PROT_EXEC, | |
308 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, | |
309 | fd_offset); | |
310 | ||
311 | if (error != N_TXTADDR(ex)) | |
312 | return error; | |
313 | ||
314 | error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, | |
315 | PROT_READ | PROT_WRITE | PROT_EXEC, | |
316 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, | |
317 | fd_offset + ex.a_text); | |
318 | if (error != N_DATADDR(ex)) | |
319 | return error; | |
320 | } | |
321 | beyond_if: | |
322 | set_binfmt(&aout_format); | |
323 | ||
324 | retval = set_brk(current->mm->start_brk, current->mm->brk); | |
325 | if (retval < 0) | |
326 | return retval; | |
327 | ||
328 | current->mm->start_stack = | |
329 | (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); | |
330 | #ifdef __alpha__ | |
331 | regs->gp = ex.a_gpvalue; | |
332 | #endif | |
333 | start_thread(regs, ex.a_entry, current->mm->start_stack); | |
334 | return 0; | |
335 | } | |
336 | ||
337 | static int load_aout_library(struct file *file) | |
338 | { | |
339 | struct inode * inode; | |
340 | unsigned long bss, start_addr, len; | |
341 | unsigned long error; | |
342 | int retval; | |
343 | struct exec ex; | |
344 | ||
345 | inode = file_inode(file); | |
346 | ||
347 | retval = -ENOEXEC; | |
348 | error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); | |
349 | if (error != sizeof(ex)) | |
350 | goto out; | |
351 | ||
352 | /* We come in here for the regular a.out style of shared libraries */ | |
353 | if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || | |
354 | N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || | |
355 | i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { | |
356 | goto out; | |
357 | } | |
358 | ||
359 | /* | |
360 | * Requires a mmap handler. This prevents people from using a.out | |
361 | * as part of an exploit attack against /proc-related vulnerabilities. | |
362 | */ | |
363 | if (!file->f_op->mmap) | |
364 | goto out; | |
365 | ||
366 | if (N_FLAGS(ex)) | |
367 | goto out; | |
368 | ||
369 | /* For QMAGIC, the starting address is 0x20 into the page. We mask | |
370 | this off to get the starting address for the page */ | |
371 | ||
372 | start_addr = ex.a_entry & 0xfffff000; | |
373 | ||
374 | if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { | |
375 | if (printk_ratelimit()) | |
376 | { | |
377 | printk(KERN_WARNING | |
378 | "N_TXTOFF is not page aligned. Please convert library: %pD\n", | |
379 | file); | |
380 | } | |
381 | vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); | |
382 | ||
383 | read_code(file, start_addr, N_TXTOFF(ex), | |
384 | ex.a_text + ex.a_data); | |
385 | retval = 0; | |
386 | goto out; | |
387 | } | |
388 | /* Now use mmap to map the library into memory. */ | |
389 | error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, | |
390 | PROT_READ | PROT_WRITE | PROT_EXEC, | |
391 | MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, | |
392 | N_TXTOFF(ex)); | |
393 | retval = error; | |
394 | if (error != start_addr) | |
395 | goto out; | |
396 | ||
397 | len = PAGE_ALIGN(ex.a_text + ex.a_data); | |
398 | bss = ex.a_text + ex.a_data + ex.a_bss; | |
399 | if (bss > len) { | |
400 | error = vm_brk(start_addr + len, bss - len); | |
401 | retval = error; | |
402 | if (error != start_addr + len) | |
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"); |