1 /*
2 * a.out loader for x86-64
3 *
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
5 * Hacked together by Andi Kleen
6 */
7
8 #include <linux/module.h>
9
10 #include <linux/time.h>
11 #include <linux/kernel.h>
12 #include <linux/mm.h>
13 #include <linux/mman.h>
14 #include <linux/a.out.h>
15 #include <linux/errno.h>
16 #include <linux/signal.h>
17 #include <linux/string.h>
18 #include <linux/fs.h>
19 #include <linux/file.h>
20 #include <linux/stat.h>
21 #include <linux/fcntl.h>
22 #include <linux/ptrace.h>
23 #include <linux/user.h>
24 #include <linux/binfmts.h>
25 #include <linux/personality.h>
26 #include <linux/init.h>
27 #include <linux/jiffies.h>
28 #include <linux/perf_event.h>
29
30 #include <asm/uaccess.h>
31 #include <asm/pgalloc.h>
32 #include <asm/cacheflush.h>
33 #include <asm/user32.h>
34 #include <asm/ia32.h>
35
36 #undef WARN_OLD
37
38 static int load_aout_binary(struct linux_binprm *);
39 static int load_aout_library(struct file *);
40
41 #ifdef CONFIG_COREDUMP
42 static int aout_core_dump(struct coredump_params *);
43
get_dr(int n)44 static unsigned long get_dr(int n)
45 {
46 struct perf_event *bp = current->thread.ptrace_bps[n];
47 return bp ? bp->hw.info.address : 0;
48 }
49
50 /*
51 * fill in the user structure for a core dump..
52 */
dump_thread32(struct pt_regs * regs,struct user32 * dump)53 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
54 {
55 u32 fs, gs;
56 memset(dump, 0, sizeof(*dump));
57
58 /* changed the size calculations - should hopefully work better. lbt */
59 dump->magic = CMAGIC;
60 dump->start_code = 0;
61 dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
62 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
63 dump->u_dsize = ((unsigned long)
64 (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
65 dump->u_dsize -= dump->u_tsize;
66 dump->u_debugreg[0] = get_dr(0);
67 dump->u_debugreg[1] = get_dr(1);
68 dump->u_debugreg[2] = get_dr(2);
69 dump->u_debugreg[3] = get_dr(3);
70 dump->u_debugreg[6] = current->thread.debugreg6;
71 dump->u_debugreg[7] = current->thread.ptrace_dr7;
72
73 if (dump->start_stack < 0xc0000000) {
74 unsigned long tmp;
75
76 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
77 dump->u_ssize = tmp >> PAGE_SHIFT;
78 }
79
80 dump->regs.ebx = regs->bx;
81 dump->regs.ecx = regs->cx;
82 dump->regs.edx = regs->dx;
83 dump->regs.esi = regs->si;
84 dump->regs.edi = regs->di;
85 dump->regs.ebp = regs->bp;
86 dump->regs.eax = regs->ax;
87 dump->regs.ds = current->thread.ds;
88 dump->regs.es = current->thread.es;
89 savesegment(fs, fs);
90 dump->regs.fs = fs;
91 savesegment(gs, gs);
92 dump->regs.gs = gs;
93 dump->regs.orig_eax = regs->orig_ax;
94 dump->regs.eip = regs->ip;
95 dump->regs.cs = regs->cs;
96 dump->regs.eflags = regs->flags;
97 dump->regs.esp = regs->sp;
98 dump->regs.ss = regs->ss;
99
100 #if 1 /* FIXME */
101 dump->u_fpvalid = 0;
102 #else
103 dump->u_fpvalid = dump_fpu(regs, &dump->i387);
104 #endif
105 }
106
107 #endif
108
109 static struct linux_binfmt aout_format = {
110 .module = THIS_MODULE,
111 .load_binary = load_aout_binary,
112 .load_shlib = load_aout_library,
113 #ifdef CONFIG_COREDUMP
114 .core_dump = aout_core_dump,
115 #endif
116 .min_coredump = PAGE_SIZE
117 };
118
set_brk(unsigned long start,unsigned long end)119 static void set_brk(unsigned long start, unsigned long end)
120 {
121 start = PAGE_ALIGN(start);
122 end = PAGE_ALIGN(end);
123 if (end <= start)
124 return;
125 vm_brk(start, end - start);
126 }
127
128 #ifdef CONFIG_COREDUMP
129 /*
130 * These are the only things you should do on a core-file: use only these
131 * macros to write out all the necessary info.
132 */
133
134 #include <linux/coredump.h>
135
136 #define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
137 #define START_STACK(u) (u.start_stack)
138
139 /*
140 * Routine writes a core dump image in the current directory.
141 * Currently only a stub-function.
142 *
143 * Note that setuid/setgid files won't make a core-dump if the uid/gid
144 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
145 * field, which also makes sure the core-dumps won't be recursive if the
146 * dumping of the process results in another error..
147 */
148
aout_core_dump(struct coredump_params * cprm)149 static int aout_core_dump(struct coredump_params *cprm)
150 {
151 mm_segment_t fs;
152 int has_dumped = 0;
153 unsigned long dump_start, dump_size;
154 struct user32 dump;
155
156 fs = get_fs();
157 set_fs(KERNEL_DS);
158 has_dumped = 1;
159 strncpy(dump.u_comm, current->comm, sizeof(current->comm));
160 dump.u_ar0 = offsetof(struct user32, regs);
161 dump.signal = cprm->siginfo->si_signo;
162 dump_thread32(cprm->regs, &dump);
163
164 /*
165 * If the size of the dump file exceeds the rlimit, then see
166 * what would happen if we wrote the stack, but not the data
167 * area.
168 */
169 if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
170 dump.u_dsize = 0;
171
172 /* Make sure we have enough room to write the stack and data areas. */
173 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
174 dump.u_ssize = 0;
175
176 /* make sure we actually have a data and stack area to dump */
177 set_fs(USER_DS);
178 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
179 dump.u_dsize << PAGE_SHIFT))
180 dump.u_dsize = 0;
181 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
182 dump.u_ssize << PAGE_SHIFT))
183 dump.u_ssize = 0;
184
185 set_fs(KERNEL_DS);
186 /* struct user */
187 if (!dump_emit(cprm, &dump, sizeof(dump)))
188 goto end_coredump;
189 /* Now dump all of the user data. Include malloced stuff as well */
190 if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
191 goto end_coredump;
192 /* now we start writing out the user space info */
193 set_fs(USER_DS);
194 /* Dump the data area */
195 if (dump.u_dsize != 0) {
196 dump_start = START_DATA(dump);
197 dump_size = dump.u_dsize << PAGE_SHIFT;
198 if (!dump_emit(cprm, (void *)dump_start, dump_size))
199 goto end_coredump;
200 }
201 /* Now prepare to dump the stack area */
202 if (dump.u_ssize != 0) {
203 dump_start = START_STACK(dump);
204 dump_size = dump.u_ssize << PAGE_SHIFT;
205 if (!dump_emit(cprm, (void *)dump_start, dump_size))
206 goto end_coredump;
207 }
208 end_coredump:
209 set_fs(fs);
210 return has_dumped;
211 }
212 #endif
213
214 /*
215 * create_aout_tables() parses the env- and arg-strings in new user
216 * memory and creates the pointer tables from them, and puts their
217 * addresses on the "stack", returning the new stack pointer value.
218 */
create_aout_tables(char __user * p,struct linux_binprm * bprm)219 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
220 {
221 u32 __user *argv, *envp, *sp;
222 int argc = bprm->argc, envc = bprm->envc;
223
224 sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
225 sp -= envc+1;
226 envp = sp;
227 sp -= argc+1;
228 argv = sp;
229 put_user((unsigned long) envp, --sp);
230 put_user((unsigned long) argv, --sp);
231 put_user(argc, --sp);
232 current->mm->arg_start = (unsigned long) p;
233 while (argc-- > 0) {
234 char c;
235
236 put_user((u32)(unsigned long)p, argv++);
237 do {
238 get_user(c, p++);
239 } while (c);
240 }
241 put_user(0, argv);
242 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
243 while (envc-- > 0) {
244 char c;
245
246 put_user((u32)(unsigned long)p, envp++);
247 do {
248 get_user(c, p++);
249 } while (c);
250 }
251 put_user(0, envp);
252 current->mm->env_end = (unsigned long) p;
253 return sp;
254 }
255
256 /*
257 * These are the functions used to load a.out style executables and shared
258 * libraries. There is no binary dependent code anywhere else.
259 */
load_aout_binary(struct linux_binprm * bprm)260 static int load_aout_binary(struct linux_binprm *bprm)
261 {
262 unsigned long error, fd_offset, rlim;
263 struct pt_regs *regs = current_pt_regs();
264 struct exec ex;
265 int retval;
266
267 ex = *((struct exec *) bprm->buf); /* exec-header */
268 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
269 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
270 N_TRSIZE(ex) || N_DRSIZE(ex) ||
271 i_size_read(file_inode(bprm->file)) <
272 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
273 return -ENOEXEC;
274 }
275
276 fd_offset = N_TXTOFF(ex);
277
278 /* Check initial limits. This avoids letting people circumvent
279 * size limits imposed on them by creating programs with large
280 * arrays in the data or bss.
281 */
282 rlim = rlimit(RLIMIT_DATA);
283 if (rlim >= RLIM_INFINITY)
284 rlim = ~0;
285 if (ex.a_data + ex.a_bss > rlim)
286 return -ENOMEM;
287
288 /* Flush all traces of the currently running executable */
289 retval = flush_old_exec(bprm);
290 if (retval)
291 return retval;
292
293 /* OK, This is the point of no return */
294 set_personality(PER_LINUX);
295 set_personality_ia32(false);
296
297 setup_new_exec(bprm);
298
299 regs->cs = __USER32_CS;
300 regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
301 regs->r13 = regs->r14 = regs->r15 = 0;
302
303 current->mm->end_code = ex.a_text +
304 (current->mm->start_code = N_TXTADDR(ex));
305 current->mm->end_data = ex.a_data +
306 (current->mm->start_data = N_DATADDR(ex));
307 current->mm->brk = ex.a_bss +
308 (current->mm->start_brk = N_BSSADDR(ex));
309
310 retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
311 if (retval < 0)
312 return retval;
313
314 install_exec_creds(bprm);
315
316 if (N_MAGIC(ex) == OMAGIC) {
317 unsigned long text_addr, map_size;
318
319 text_addr = N_TXTADDR(ex);
320 map_size = ex.a_text+ex.a_data;
321
322 error = vm_brk(text_addr & PAGE_MASK, map_size);
323
324 if (error != (text_addr & PAGE_MASK))
325 return error;
326
327 error = read_code(bprm->file, text_addr, 32,
328 ex.a_text + ex.a_data);
329 if ((signed long)error < 0)
330 return error;
331 } else {
332 #ifdef WARN_OLD
333 static unsigned long error_time, error_time2;
334 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
335 (N_MAGIC(ex) != NMAGIC) &&
336 time_after(jiffies, error_time2 + 5*HZ)) {
337 printk(KERN_NOTICE "executable not page aligned\n");
338 error_time2 = jiffies;
339 }
340
341 if ((fd_offset & ~PAGE_MASK) != 0 &&
342 time_after(jiffies, error_time + 5*HZ)) {
343 printk(KERN_WARNING
344 "fd_offset is not page aligned. Please convert "
345 "program: %s\n",
346 bprm->file->f_path.dentry->d_name.name);
347 error_time = jiffies;
348 }
349 #endif
350
351 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
352 vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
353 read_code(bprm->file, N_TXTADDR(ex), fd_offset,
354 ex.a_text+ex.a_data);
355 goto beyond_if;
356 }
357
358 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
359 PROT_READ | PROT_EXEC,
360 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
361 MAP_EXECUTABLE | MAP_32BIT,
362 fd_offset);
363
364 if (error != N_TXTADDR(ex))
365 return error;
366
367 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
368 PROT_READ | PROT_WRITE | PROT_EXEC,
369 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
370 MAP_EXECUTABLE | MAP_32BIT,
371 fd_offset + ex.a_text);
372 if (error != N_DATADDR(ex))
373 return error;
374 }
375 beyond_if:
376 set_binfmt(&aout_format);
377
378 set_brk(current->mm->start_brk, current->mm->brk);
379
380 current->mm->start_stack =
381 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
382 /* start thread */
383 loadsegment(fs, 0);
384 loadsegment(ds, __USER32_DS);
385 loadsegment(es, __USER32_DS);
386 load_gs_index(0);
387 (regs)->ip = ex.a_entry;
388 (regs)->sp = current->mm->start_stack;
389 (regs)->flags = 0x200;
390 (regs)->cs = __USER32_CS;
391 (regs)->ss = __USER32_DS;
392 regs->r8 = regs->r9 = regs->r10 = regs->r11 =
393 regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
394 set_fs(USER_DS);
395 return 0;
396 }
397
load_aout_library(struct file * file)398 static int load_aout_library(struct file *file)
399 {
400 unsigned long bss, start_addr, len, error;
401 int retval;
402 struct exec ex;
403
404
405 retval = -ENOEXEC;
406 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
407 if (error != sizeof(ex))
408 goto out;
409
410 /* We come in here for the regular a.out style of shared libraries */
411 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
412 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
413 i_size_read(file_inode(file)) <
414 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
415 goto out;
416 }
417
418 if (N_FLAGS(ex))
419 goto out;
420
421 /* For QMAGIC, the starting address is 0x20 into the page. We mask
422 this off to get the starting address for the page */
423
424 start_addr = ex.a_entry & 0xfffff000;
425
426 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
427 #ifdef WARN_OLD
428 static unsigned long error_time;
429 if (time_after(jiffies, error_time + 5*HZ)) {
430 printk(KERN_WARNING
431 "N_TXTOFF is not page aligned. Please convert "
432 "library: %s\n",
433 file->f_path.dentry->d_name.name);
434 error_time = jiffies;
435 }
436 #endif
437 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
438
439 read_code(file, start_addr, N_TXTOFF(ex),
440 ex.a_text + ex.a_data);
441 retval = 0;
442 goto out;
443 }
444 /* Now use mmap to map the library into memory. */
445 error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
446 PROT_READ | PROT_WRITE | PROT_EXEC,
447 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
448 N_TXTOFF(ex));
449 retval = error;
450 if (error != start_addr)
451 goto out;
452
453 len = PAGE_ALIGN(ex.a_text + ex.a_data);
454 bss = ex.a_text + ex.a_data + ex.a_bss;
455 if (bss > len) {
456 error = vm_brk(start_addr + len, bss - len);
457 retval = error;
458 if (error != start_addr + len)
459 goto out;
460 }
461 retval = 0;
462 out:
463 return retval;
464 }
465
init_aout_binfmt(void)466 static int __init init_aout_binfmt(void)
467 {
468 register_binfmt(&aout_format);
469 return 0;
470 }
471
exit_aout_binfmt(void)472 static void __exit exit_aout_binfmt(void)
473 {
474 unregister_binfmt(&aout_format);
475 }
476
477 module_init(init_aout_binfmt);
478 module_exit(exit_aout_binfmt);
479 MODULE_LICENSE("GPL");
480