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CommitLineData
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>
1da177e4
LT
23#include <linux/binfmts.h>
24#include <linux/personality.h>
25#include <linux/init.h>
088e7af7 26#include <linux/coredump.h>
5a0e3ad6 27#include <linux/slab.h>
68db0cf1 28#include <linux/sched/task_stack.h>
1da177e4 29
7c0f6ba6 30#include <linux/uaccess.h>
1da177e4 31#include <asm/cacheflush.h>
7fa30315 32#include <asm/a.out-core.h>
1da177e4 33
71613c3b 34static int load_aout_binary(struct linux_binprm *);
1da177e4 35static int load_aout_library(struct file*);
1da177e4 36
046d662f 37#ifdef CONFIG_COREDUMP
1da177e4
LT
38/*
39 * Routine writes a core dump image in the current directory.
40 * Currently only a stub-function.
41 *
42 * Note that setuid/setgid files won't make a core-dump if the uid/gid
43 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
44 * field, which also makes sure the core-dumps won't be recursive if the
45 * dumping of the process results in another error..
46 */
f6151dfe 47static int aout_core_dump(struct coredump_params *cprm)
1da177e4
LT
48{
49 mm_segment_t fs;
50 int has_dumped = 0;
7731d9a5
BP
51 void __user *dump_start;
52 int dump_size;
1da177e4 53 struct user dump;
17580d7f 54#ifdef __alpha__
7731d9a5 55# define START_DATA(u) ((void __user *)u.start_data)
17580d7f 56#else
7731d9a5
BP
57# define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \
58 u.start_code))
1da177e4 59#endif
7731d9a5 60# define START_STACK(u) ((void __user *)u.start_stack)
1da177e4
LT
61
62 fs = get_fs();
63 set_fs(KERNEL_DS);
64 has_dumped = 1;
1da177e4 65 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
6e16d89b 66 dump.u_ar0 = offsetof(struct user, regs);
5ab1c309 67 dump.signal = cprm->siginfo->si_signo;
f6151dfe 68 aout_dump_thread(cprm->regs, &dump);
1da177e4
LT
69
70/* If the size of the dump file exceeds the rlimit, then see what would happen
71 if we wrote the stack, but not the data area. */
f6151dfe 72 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
1da177e4 73 dump.u_dsize = 0;
1da177e4
LT
74
75/* Make sure we have enough room to write the stack and data areas. */
f6151dfe 76 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
1da177e4 77 dump.u_ssize = 0;
1da177e4
LT
78
79/* make sure we actually have a data and stack area to dump */
80 set_fs(USER_DS);
7731d9a5 81 if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
1da177e4 82 dump.u_dsize = 0;
7731d9a5 83 if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
1da177e4 84 dump.u_ssize = 0;
1da177e4
LT
85
86 set_fs(KERNEL_DS);
87/* struct user */
43a5d548 88 if (!dump_emit(cprm, &dump, sizeof(dump)))
088e7af7 89 goto end_coredump;
1da177e4 90/* Now dump all of the user data. Include malloced stuff as well */
9b56d543 91 if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
05f47fda 92 goto end_coredump;
1da177e4
LT
93/* now we start writing out the user space info */
94 set_fs(USER_DS);
95/* Dump the data area */
96 if (dump.u_dsize != 0) {
97 dump_start = START_DATA(dump);
1da177e4 98 dump_size = dump.u_dsize << PAGE_SHIFT;
43a5d548 99 if (!dump_emit(cprm, dump_start, dump_size))
088e7af7 100 goto end_coredump;
1da177e4
LT
101 }
102/* Now prepare to dump the stack area */
103 if (dump.u_ssize != 0) {
104 dump_start = START_STACK(dump);
1da177e4 105 dump_size = dump.u_ssize << PAGE_SHIFT;
43a5d548 106 if (!dump_emit(cprm, dump_start, dump_size))
088e7af7 107 goto end_coredump;
1da177e4 108 }
1da177e4
LT
109end_coredump:
110 set_fs(fs);
111 return has_dumped;
112}
046d662f
AK
113#else
114#define aout_core_dump NULL
115#endif
116
117static struct linux_binfmt aout_format = {
118 .module = THIS_MODULE,
119 .load_binary = load_aout_binary,
120 .load_shlib = load_aout_library,
121 .core_dump = aout_core_dump,
122 .min_coredump = PAGE_SIZE
123};
124
125#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
126
127static int set_brk(unsigned long start, unsigned long end)
128{
129 start = PAGE_ALIGN(start);
130 end = PAGE_ALIGN(end);
5d22fc25
LT
131 if (end > start)
132 return vm_brk(start, end - start);
046d662f
AK
133 return 0;
134}
1da177e4
LT
135
136/*
137 * create_aout_tables() parses the env- and arg-strings in new user
138 * memory and creates the pointer tables from them, and puts their
139 * addresses on the "stack", returning the new stack pointer value.
140 */
141static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
142{
143 char __user * __user *argv;
144 char __user * __user *envp;
145 unsigned long __user *sp;
146 int argc = bprm->argc;
147 int envc = bprm->envc;
148
149 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
1da177e4
LT
150#ifdef __alpha__
151/* whee.. test-programs are so much fun. */
152 put_user(0, --sp);
153 put_user(0, --sp);
154 if (bprm->loader) {
155 put_user(0, --sp);
17580d7f 156 put_user(1003, --sp);
1da177e4 157 put_user(bprm->loader, --sp);
17580d7f 158 put_user(1002, --sp);
1da177e4
LT
159 }
160 put_user(bprm->exec, --sp);
17580d7f 161 put_user(1001, --sp);
1da177e4
LT
162#endif
163 sp -= envc+1;
164 envp = (char __user * __user *) sp;
165 sp -= argc+1;
166 argv = (char __user * __user *) sp;
17580d7f 167#ifndef __alpha__
1da177e4
LT
168 put_user((unsigned long) envp,--sp);
169 put_user((unsigned long) argv,--sp);
170#endif
171 put_user(argc,--sp);
172 current->mm->arg_start = (unsigned long) p;
173 while (argc-->0) {
174 char c;
175 put_user(p,argv++);
176 do {
177 get_user(c,p++);
178 } while (c);
179 }
180 put_user(NULL,argv);
181 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
182 while (envc-->0) {
183 char c;
184 put_user(p,envp++);
185 do {
186 get_user(c,p++);
187 } while (c);
188 }
189 put_user(NULL,envp);
190 current->mm->env_end = (unsigned long) p;
191 return sp;
192}
193
194/*
195 * These are the functions used to load a.out style executables and shared
196 * libraries. There is no binary dependent code anywhere else.
197 */
198
71613c3b 199static int load_aout_binary(struct linux_binprm * bprm)
1da177e4 200{
71613c3b 201 struct pt_regs *regs = current_pt_regs();
1da177e4
LT
202 struct exec ex;
203 unsigned long error;
204 unsigned long fd_offset;
205 unsigned long rlim;
206 int retval;
207
208 ex = *((struct exec *) bprm->buf); /* exec-header */
209 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
210 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
211 N_TRSIZE(ex) || N_DRSIZE(ex) ||
496ad9aa 212 i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
1da177e4
LT
213 return -ENOEXEC;
214 }
215
8454aeef
ET
216 /*
217 * Requires a mmap handler. This prevents people from using a.out
218 * as part of an exploit attack against /proc-related vulnerabilities.
219 */
72c2d531 220 if (!bprm->file->f_op->mmap)
8454aeef
ET
221 return -ENOEXEC;
222
1da177e4
LT
223 fd_offset = N_TXTOFF(ex);
224
225 /* Check initial limits. This avoids letting people circumvent
226 * size limits imposed on them by creating programs with large
227 * arrays in the data or bss.
228 */
d554ed89 229 rlim = rlimit(RLIMIT_DATA);
1da177e4
LT
230 if (rlim >= RLIM_INFINITY)
231 rlim = ~0;
232 if (ex.a_data + ex.a_bss > rlim)
233 return -ENOMEM;
234
235 /* Flush all traces of the currently running executable */
236 retval = flush_old_exec(bprm);
237 if (retval)
238 return retval;
239
240 /* OK, This is the point of no return */
17580d7f 241#ifdef __alpha__
1da177e4 242 SET_AOUT_PERSONALITY(bprm, ex);
1da177e4
LT
243#else
244 set_personality(PER_LINUX);
245#endif
221af7f8 246 setup_new_exec(bprm);
1da177e4
LT
247
248 current->mm->end_code = ex.a_text +
249 (current->mm->start_code = N_TXTADDR(ex));
250 current->mm->end_data = ex.a_data +
251 (current->mm->start_data = N_DATADDR(ex));
252 current->mm->brk = ex.a_bss +
253 (current->mm->start_brk = N_BSSADDR(ex));
1da177e4 254
6414fa6a 255 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
19d860a1 256 if (retval < 0)
6414fa6a 257 return retval;
6414fa6a 258
a6f76f23 259 install_exec_creds(bprm);
1da177e4
LT
260
261 if (N_MAGIC(ex) == OMAGIC) {
262 unsigned long text_addr, map_size;
263 loff_t pos;
264
265 text_addr = N_TXTADDR(ex);
266
fe30af97 267#ifdef __alpha__
1da177e4
LT
268 pos = fd_offset;
269 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
270#else
271 pos = 32;
272 map_size = ex.a_text+ex.a_data;
273#endif
e4eb1ff6 274 error = vm_brk(text_addr & PAGE_MASK, map_size);
5d22fc25 275 if (error)
1da177e4 276 return error;
1da177e4 277
3dc20cb2
AV
278 error = read_code(bprm->file, text_addr, pos,
279 ex.a_text+ex.a_data);
19d860a1 280 if ((signed long)error < 0)
1da177e4 281 return error;
1da177e4 282 } else {
1da177e4 283 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
2e50b6cc 284 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
1da177e4
LT
285 {
286 printk(KERN_NOTICE "executable not page aligned\n");
1da177e4
LT
287 }
288
2e50b6cc 289 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
1da177e4
LT
290 {
291 printk(KERN_WARNING
a455589f
AV
292 "fd_offset is not page aligned. Please convert program: %pD\n",
293 bprm->file);
1da177e4
LT
294 }
295
296 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
864778b1 297 error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
5d22fc25 298 if (error)
864778b1
MH
299 return error;
300
3dc20cb2
AV
301 read_code(bprm->file, N_TXTADDR(ex), fd_offset,
302 ex.a_text + ex.a_data);
1da177e4
LT
303 goto beyond_if;
304 }
305
6be5ceb0 306 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
1da177e4
LT
307 PROT_READ | PROT_EXEC,
308 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
309 fd_offset);
1da177e4 310
19d860a1 311 if (error != N_TXTADDR(ex))
1da177e4 312 return error;
1da177e4 313
6be5ceb0 314 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
1da177e4
LT
315 PROT_READ | PROT_WRITE | PROT_EXEC,
316 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
317 fd_offset + ex.a_text);
19d860a1 318 if (error != N_DATADDR(ex))
1da177e4 319 return error;
1da177e4
LT
320 }
321beyond_if:
322 set_binfmt(&aout_format);
323
324 retval = set_brk(current->mm->start_brk, current->mm->brk);
19d860a1 325 if (retval < 0)
1da177e4 326 return retval;
1da177e4 327
1da177e4
LT
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);
1da177e4
LT
334 return 0;
335}
336
337static 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
496ad9aa 345 inode = file_inode(file);
1da177e4
LT
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
8454aeef
ET
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 */
72c2d531 363 if (!file->f_op->mmap)
8454aeef
ET
364 goto out;
365
1da177e4
LT
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) {
2e50b6cc 375 if (printk_ratelimit())
1da177e4
LT
376 {
377 printk(KERN_WARNING
a455589f
AV
378 "N_TXTOFF is not page aligned. Please convert library: %pD\n",
379 file);
1da177e4 380 }
864778b1 381 retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
5d22fc25 382 if (retval)
864778b1
MH
383 goto out;
384
3dc20cb2
AV
385 read_code(file, start_addr, N_TXTOFF(ex),
386 ex.a_text + ex.a_data);
1da177e4
LT
387 retval = 0;
388 goto out;
389 }
390 /* Now use mmap to map the library into memory. */
6be5ceb0 391 error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
1da177e4
LT
392 PROT_READ | PROT_WRITE | PROT_EXEC,
393 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
394 N_TXTOFF(ex));
1da177e4
LT
395 retval = error;
396 if (error != start_addr)
397 goto out;
398
399 len = PAGE_ALIGN(ex.a_text + ex.a_data);
400 bss = ex.a_text + ex.a_data + ex.a_bss;
401 if (bss > len) {
5d22fc25
LT
402 retval = vm_brk(start_addr + len, bss - len);
403 if (retval)
1da177e4
LT
404 goto out;
405 }
406 retval = 0;
407out:
408 return retval;
409}
410
411static int __init init_aout_binfmt(void)
412{
8fc3dc5a
AV
413 register_binfmt(&aout_format);
414 return 0;
1da177e4
LT
415}
416
417static void __exit exit_aout_binfmt(void)
418{
419 unregister_binfmt(&aout_format);
420}
421
422core_initcall(init_aout_binfmt);
423module_exit(exit_aout_binfmt);
424MODULE_LICENSE("GPL");