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 #include <linux/sched/task_stack.h>
30
31 #include <linux/uaccess.h>
32 #include <asm/pgalloc.h>
33 #include <asm/cacheflush.h>
34 #include <asm/user32.h>
35 #include <asm/ia32.h>
36
37 #undef WARN_OLD
38
39 static int load_aout_binary(struct linux_binprm *);
40 static int load_aout_library(struct file *);
41
42 #ifdef CONFIG_COREDUMP
43 static int aout_core_dump(struct coredump_params *);
44
get_dr(int n)45 static unsigned long get_dr(int n)
46 {
47 struct perf_event *bp = current->thread.ptrace_bps[n];
48 return bp ? bp->hw.info.address : 0;
49 }
50
51 /*
52 * fill in the user structure for a core dump..
53 */
fill_dump(struct pt_regs * regs,struct user32 * dump)54 static void fill_dump(struct pt_regs *regs, struct user32 *dump)
55 {
56 u32 fs, gs;
57 memset(dump, 0, sizeof(*dump));
58
59 /* changed the size calculations - should hopefully work better. lbt */
60 dump->magic = CMAGIC;
61 dump->start_code = 0;
62 dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
63 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
64 dump->u_dsize = ((unsigned long)
65 (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
66 dump->u_dsize -= dump->u_tsize;
67 dump->u_debugreg[0] = get_dr(0);
68 dump->u_debugreg[1] = get_dr(1);
69 dump->u_debugreg[2] = get_dr(2);
70 dump->u_debugreg[3] = get_dr(3);
71 dump->u_debugreg[6] = current->thread.debugreg6;
72 dump->u_debugreg[7] = current->thread.ptrace_dr7;
73
74 if (dump->start_stack < 0xc0000000) {
75 unsigned long tmp;
76
77 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
78 dump->u_ssize = tmp >> PAGE_SHIFT;
79 }
80
81 dump->regs.ebx = regs->bx;
82 dump->regs.ecx = regs->cx;
83 dump->regs.edx = regs->dx;
84 dump->regs.esi = regs->si;
85 dump->regs.edi = regs->di;
86 dump->regs.ebp = regs->bp;
87 dump->regs.eax = regs->ax;
88 dump->regs.ds = current->thread.ds;
89 dump->regs.es = current->thread.es;
90 savesegment(fs, fs);
91 dump->regs.fs = fs;
92 savesegment(gs, gs);
93 dump->regs.gs = gs;
94 dump->regs.orig_eax = regs->orig_ax;
95 dump->regs.eip = regs->ip;
96 dump->regs.cs = regs->cs;
97 dump->regs.eflags = regs->flags;
98 dump->regs.esp = regs->sp;
99 dump->regs.ss = regs->ss;
100
101 #if 1 /* FIXME */
102 dump->u_fpvalid = 0;
103 #else
104 dump->u_fpvalid = dump_fpu(regs, &dump->i387);
105 #endif
106 }
107
108 #endif
109
110 static struct linux_binfmt aout_format = {
111 .module = THIS_MODULE,
112 .load_binary = load_aout_binary,
113 .load_shlib = load_aout_library,
114 #ifdef CONFIG_COREDUMP
115 .core_dump = aout_core_dump,
116 #endif
117 .min_coredump = PAGE_SIZE
118 };
119
set_brk(unsigned long start,unsigned long end)120 static int set_brk(unsigned long start, unsigned long end)
121 {
122 start = PAGE_ALIGN(start);
123 end = PAGE_ALIGN(end);
124 if (end <= start)
125 return 0;
126 return vm_brk(start, end - start);
127 }
128
129 #ifdef CONFIG_COREDUMP
130 /*
131 * These are the only things you should do on a core-file: use only these
132 * macros to write out all the necessary info.
133 */
134
135 #include <linux/coredump.h>
136
137 #define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
138 #define START_STACK(u) (u.start_stack)
139
140 /*
141 * Routine writes a core dump image in the current directory.
142 * Currently only a stub-function.
143 *
144 * Note that setuid/setgid files won't make a core-dump if the uid/gid
145 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
146 * field, which also makes sure the core-dumps won't be recursive if the
147 * dumping of the process results in another error..
148 */
149
aout_core_dump(struct coredump_params * cprm)150 static int aout_core_dump(struct coredump_params *cprm)
151 {
152 mm_segment_t fs;
153 int has_dumped = 0;
154 unsigned long dump_start, dump_size;
155 struct user32 dump;
156
157 fs = get_fs();
158 set_fs(KERNEL_DS);
159 has_dumped = 1;
160
161 fill_dump(cprm->regs, &dump);
162
163 strncpy(dump.u_comm, current->comm, sizeof(current->comm));
164 dump.u_ar0 = offsetof(struct user32, regs);
165 dump.signal = cprm->siginfo->si_signo;
166
167 /*
168 * If the size of the dump file exceeds the rlimit, then see
169 * what would happen if we wrote the stack, but not the data
170 * area.
171 */
172 if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
173 dump.u_dsize = 0;
174
175 /* Make sure we have enough room to write the stack and data areas. */
176 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
177 dump.u_ssize = 0;
178
179 /* make sure we actually have a data and stack area to dump */
180 set_fs(USER_DS);
181 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
182 dump.u_dsize << PAGE_SHIFT))
183 dump.u_dsize = 0;
184 if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
185 dump.u_ssize << PAGE_SHIFT))
186 dump.u_ssize = 0;
187
188 set_fs(KERNEL_DS);
189 /* struct user */
190 if (!dump_emit(cprm, &dump, sizeof(dump)))
191 goto end_coredump;
192 /* Now dump all of the user data. Include malloced stuff as well */
193 if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
194 goto end_coredump;
195 /* now we start writing out the user space info */
196 set_fs(USER_DS);
197 /* Dump the data area */
198 if (dump.u_dsize != 0) {
199 dump_start = START_DATA(dump);
200 dump_size = dump.u_dsize << PAGE_SHIFT;
201 if (!dump_emit(cprm, (void *)dump_start, dump_size))
202 goto end_coredump;
203 }
204 /* Now prepare to dump the stack area */
205 if (dump.u_ssize != 0) {
206 dump_start = START_STACK(dump);
207 dump_size = dump.u_ssize << PAGE_SHIFT;
208 if (!dump_emit(cprm, (void *)dump_start, dump_size))
209 goto end_coredump;
210 }
211 end_coredump:
212 set_fs(fs);
213 return has_dumped;
214 }
215 #endif
216
217 /*
218 * create_aout_tables() parses the env- and arg-strings in new user
219 * memory and creates the pointer tables from them, and puts their
220 * addresses on the "stack", returning the new stack pointer value.
221 */
create_aout_tables(char __user * p,struct linux_binprm * bprm)222 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
223 {
224 u32 __user *argv, *envp, *sp;
225 int argc = bprm->argc, envc = bprm->envc;
226
227 sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
228 sp -= envc+1;
229 envp = sp;
230 sp -= argc+1;
231 argv = sp;
232 put_user((unsigned long) envp, --sp);
233 put_user((unsigned long) argv, --sp);
234 put_user(argc, --sp);
235 current->mm->arg_start = (unsigned long) p;
236 while (argc-- > 0) {
237 char c;
238
239 put_user((u32)(unsigned long)p, argv++);
240 do {
241 get_user(c, p++);
242 } while (c);
243 }
244 put_user(0, argv);
245 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
246 while (envc-- > 0) {
247 char c;
248
249 put_user((u32)(unsigned long)p, envp++);
250 do {
251 get_user(c, p++);
252 } while (c);
253 }
254 put_user(0, envp);
255 current->mm->env_end = (unsigned long) p;
256 return sp;
257 }
258
259 /*
260 * These are the functions used to load a.out style executables and shared
261 * libraries. There is no binary dependent code anywhere else.
262 */
load_aout_binary(struct linux_binprm * bprm)263 static int load_aout_binary(struct linux_binprm *bprm)
264 {
265 unsigned long error, fd_offset, rlim;
266 struct pt_regs *regs = current_pt_regs();
267 struct exec ex;
268 int retval;
269
270 ex = *((struct exec *) bprm->buf); /* exec-header */
271 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
272 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
273 N_TRSIZE(ex) || N_DRSIZE(ex) ||
274 i_size_read(file_inode(bprm->file)) <
275 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
276 return -ENOEXEC;
277 }
278
279 fd_offset = N_TXTOFF(ex);
280
281 /* Check initial limits. This avoids letting people circumvent
282 * size limits imposed on them by creating programs with large
283 * arrays in the data or bss.
284 */
285 rlim = rlimit(RLIMIT_DATA);
286 if (rlim >= RLIM_INFINITY)
287 rlim = ~0;
288 if (ex.a_data + ex.a_bss > rlim)
289 return -ENOMEM;
290
291 /* Flush all traces of the currently running executable */
292 retval = flush_old_exec(bprm);
293 if (retval)
294 return retval;
295
296 /* OK, This is the point of no return */
297 set_personality(PER_LINUX);
298 set_personality_ia32(false);
299
300 setup_new_exec(bprm);
301
302 regs->cs = __USER32_CS;
303 regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
304 regs->r13 = regs->r14 = regs->r15 = 0;
305
306 current->mm->end_code = ex.a_text +
307 (current->mm->start_code = N_TXTADDR(ex));
308 current->mm->end_data = ex.a_data +
309 (current->mm->start_data = N_DATADDR(ex));
310 current->mm->brk = ex.a_bss +
311 (current->mm->start_brk = N_BSSADDR(ex));
312
313 retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
314 if (retval < 0)
315 return retval;
316
317 install_exec_creds(bprm);
318
319 if (N_MAGIC(ex) == OMAGIC) {
320 unsigned long text_addr, map_size;
321
322 text_addr = N_TXTADDR(ex);
323 map_size = ex.a_text+ex.a_data;
324
325 error = vm_brk(text_addr & PAGE_MASK, map_size);
326
327 if (error)
328 return error;
329
330 error = read_code(bprm->file, text_addr, 32,
331 ex.a_text + ex.a_data);
332 if ((signed long)error < 0)
333 return error;
334 } else {
335 #ifdef WARN_OLD
336 static unsigned long error_time, error_time2;
337 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
338 (N_MAGIC(ex) != NMAGIC) &&
339 time_after(jiffies, error_time2 + 5*HZ)) {
340 printk(KERN_NOTICE "executable not page aligned\n");
341 error_time2 = jiffies;
342 }
343
344 if ((fd_offset & ~PAGE_MASK) != 0 &&
345 time_after(jiffies, error_time + 5*HZ)) {
346 printk(KERN_WARNING
347 "fd_offset is not page aligned. Please convert "
348 "program: %pD\n",
349 bprm->file);
350 error_time = jiffies;
351 }
352 #endif
353
354 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
355 error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
356 if (error)
357 return error;
358
359 read_code(bprm->file, N_TXTADDR(ex), fd_offset,
360 ex.a_text+ex.a_data);
361 goto beyond_if;
362 }
363
364 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
365 PROT_READ | PROT_EXEC,
366 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
367 MAP_EXECUTABLE | MAP_32BIT,
368 fd_offset);
369
370 if (error != N_TXTADDR(ex))
371 return error;
372
373 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
374 PROT_READ | PROT_WRITE | PROT_EXEC,
375 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
376 MAP_EXECUTABLE | MAP_32BIT,
377 fd_offset + ex.a_text);
378 if (error != N_DATADDR(ex))
379 return error;
380 }
381
382 beyond_if:
383 error = set_brk(current->mm->start_brk, current->mm->brk);
384 if (error)
385 return error;
386
387 set_binfmt(&aout_format);
388
389 current->mm->start_stack =
390 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
391 /* start thread */
392 loadsegment(fs, 0);
393 loadsegment(ds, __USER32_DS);
394 loadsegment(es, __USER32_DS);
395 load_gs_index(0);
396 (regs)->ip = ex.a_entry;
397 (regs)->sp = current->mm->start_stack;
398 (regs)->flags = 0x200;
399 (regs)->cs = __USER32_CS;
400 (regs)->ss = __USER32_DS;
401 regs->r8 = regs->r9 = regs->r10 = regs->r11 =
402 regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
403 set_fs(USER_DS);
404 return 0;
405 }
406
load_aout_library(struct file * file)407 static int load_aout_library(struct file *file)
408 {
409 unsigned long bss, start_addr, len, error;
410 int retval;
411 struct exec ex;
412 loff_t pos = 0;
413
414 retval = -ENOEXEC;
415 error = kernel_read(file, &ex, sizeof(ex), &pos);
416 if (error != sizeof(ex))
417 goto out;
418
419 /* We come in here for the regular a.out style of shared libraries */
420 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
421 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
422 i_size_read(file_inode(file)) <
423 ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
424 goto out;
425 }
426
427 if (N_FLAGS(ex))
428 goto out;
429
430 /* For QMAGIC, the starting address is 0x20 into the page. We mask
431 this off to get the starting address for the page */
432
433 start_addr = ex.a_entry & 0xfffff000;
434
435 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
436 #ifdef WARN_OLD
437 static unsigned long error_time;
438 if (time_after(jiffies, error_time + 5*HZ)) {
439 printk(KERN_WARNING
440 "N_TXTOFF is not page aligned. Please convert "
441 "library: %pD\n",
442 file);
443 error_time = jiffies;
444 }
445 #endif
446 retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
447 if (retval)
448 goto out;
449
450 read_code(file, start_addr, N_TXTOFF(ex),
451 ex.a_text + ex.a_data);
452 retval = 0;
453 goto out;
454 }
455 /* Now use mmap to map the library into memory. */
456 error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
457 PROT_READ | PROT_WRITE | PROT_EXEC,
458 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
459 N_TXTOFF(ex));
460 retval = error;
461 if (error != start_addr)
462 goto out;
463
464 len = PAGE_ALIGN(ex.a_text + ex.a_data);
465 bss = ex.a_text + ex.a_data + ex.a_bss;
466 if (bss > len) {
467 retval = vm_brk(start_addr + len, bss - len);
468 if (retval)
469 goto out;
470 }
471 retval = 0;
472 out:
473 return retval;
474 }
475
init_aout_binfmt(void)476 static int __init init_aout_binfmt(void)
477 {
478 register_binfmt(&aout_format);
479 return 0;
480 }
481
exit_aout_binfmt(void)482 static void __exit exit_aout_binfmt(void)
483 {
484 unregister_binfmt(&aout_format);
485 }
486
487 module_init(init_aout_binfmt);
488 module_exit(exit_aout_binfmt);
489 MODULE_LICENSE("GPL");
490