2 * linux/fs/binfmt_aout.c
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
7 #include <linux/module.h>
9 #include <linux/time.h>
10 #include <linux/kernel.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>
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/slab.h>
24 #include <linux/binfmts.h>
25 #include <linux/personality.h>
26 #include <linux/init.h>
27 #include <linux/vs_base.h>
28 #include <linux/vs_memory.h>
30 #include <asm/system.h>
31 #include <asm/uaccess.h>
32 #include <asm/cacheflush.h>
34 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
35 static int load_aout_library(struct file*);
36 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
38 static struct linux_binfmt aout_format = {
39 .module = THIS_MODULE,
40 .load_binary = load_aout_binary,
41 .load_shlib = load_aout_library,
42 .core_dump = aout_core_dump,
43 .min_coredump = PAGE_SIZE
46 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
48 static int set_brk(unsigned long start, unsigned long end)
50 start = PAGE_ALIGN(start);
51 end = PAGE_ALIGN(end);
54 down_write(¤t->mm->mmap_sem);
55 addr = do_brk(start, end - start);
56 up_write(¤t->mm->mmap_sem);
64 * These are the only things you should do on a core-file: use only these
65 * macros to write out all the necessary info.
68 static int dump_write(struct file *file, const void *addr, int nr)
70 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
73 #define DUMP_WRITE(addr, nr) \
74 if (!dump_write(file, (void *)(addr), (nr))) \
77 #define DUMP_SEEK(offset) \
78 if (file->f_op->llseek) { \
79 if (file->f_op->llseek(file,(offset),0) != (offset)) \
81 } else file->f_pos = (offset)
84 * Routine writes a core dump image in the current directory.
85 * Currently only a stub-function.
87 * Note that setuid/setgid files won't make a core-dump if the uid/gid
88 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
89 * field, which also makes sure the core-dumps won't be recursive if the
90 * dumping of the process results in another error..
93 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
97 unsigned long dump_start, dump_size;
99 #if defined(__alpha__)
100 # define START_DATA(u) (u.start_data)
101 #elif defined(__arm__)
102 # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
103 #elif defined(__sparc__)
104 # define START_DATA(u) (u.u_tsize)
105 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
106 # define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
109 # define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
111 # define START_STACK(u) (u.start_stack)
117 current->flags |= PF_DUMPCORE;
118 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
120 dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
123 dump_thread(regs, &dump);
125 /* If the size of the dump file exceeds the rlimit, then see what would happen
126 if we wrote the stack, but not the data area. */
128 if ((dump.u_dsize+dump.u_ssize) >
129 current->signal->rlim[RLIMIT_CORE].rlim_cur)
132 if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
133 current->signal->rlim[RLIMIT_CORE].rlim_cur)
137 /* Make sure we have enough room to write the stack and data areas. */
140 current->signal->rlim[RLIMIT_CORE].rlim_cur)
143 if ((dump.u_ssize+1) * PAGE_SIZE >
144 current->signal->rlim[RLIMIT_CORE].rlim_cur)
148 /* make sure we actually have a data and stack area to dump */
151 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize))
153 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize))
156 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
158 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
164 DUMP_WRITE(&dump,sizeof(dump));
165 /* Now dump all of the user data. Include malloced stuff as well */
167 DUMP_SEEK(PAGE_SIZE);
169 /* now we start writing out the user space info */
171 /* Dump the data area */
172 if (dump.u_dsize != 0) {
173 dump_start = START_DATA(dump);
175 dump_size = dump.u_dsize;
177 dump_size = dump.u_dsize << PAGE_SHIFT;
179 DUMP_WRITE(dump_start,dump_size);
181 /* Now prepare to dump the stack area */
182 if (dump.u_ssize != 0) {
183 dump_start = START_STACK(dump);
185 dump_size = dump.u_ssize;
187 dump_size = dump.u_ssize << PAGE_SHIFT;
189 DUMP_WRITE(dump_start,dump_size);
191 /* Finally dump the task struct. Not be used by gdb, but could be useful */
193 DUMP_WRITE(current,sizeof(*current));
200 * create_aout_tables() parses the env- and arg-strings in new user
201 * memory and creates the pointer tables from them, and puts their
202 * addresses on the "stack", returning the new stack pointer value.
204 static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
206 char __user * __user *argv;
207 char __user * __user *envp;
208 unsigned long __user *sp;
209 int argc = bprm->argc;
210 int envc = bprm->envc;
212 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
214 /* This imposes the proper stack alignment for a new process. */
215 sp = (void __user *) (((unsigned long) sp) & ~7);
216 if ((envc+argc+3)&1) --sp;
219 /* whee.. test-programs are so much fun. */
224 put_user(0x3eb, --sp);
225 put_user(bprm->loader, --sp);
226 put_user(0x3ea, --sp);
228 put_user(bprm->exec, --sp);
229 put_user(0x3e9, --sp);
232 envp = (char __user * __user *) sp;
234 argv = (char __user * __user *) sp;
235 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
236 put_user((unsigned long) envp,--sp);
237 put_user((unsigned long) argv,--sp);
240 current->mm->arg_start = (unsigned long) p;
249 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
258 current->mm->env_end = (unsigned long) p;
263 * These are the functions used to load a.out style executables and shared
264 * libraries. There is no binary dependent code anywhere else.
267 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
271 unsigned long fd_offset;
275 ex = *((struct exec *) bprm->buf); /* exec-header */
276 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
277 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
278 N_TRSIZE(ex) || N_DRSIZE(ex) ||
279 i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
284 * Requires a mmap handler. This prevents people from using a.out
285 * as part of an exploit attack against /proc-related vulnerabilities.
287 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
290 fd_offset = N_TXTOFF(ex);
292 /* Check initial limits. This avoids letting people circumvent
293 * size limits imposed on them by creating programs with large
294 * arrays in the data or bss.
296 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
297 if (rlim >= RLIM_INFINITY)
299 if (ex.a_data + ex.a_bss > rlim)
302 /* Flush all traces of the currently running executable */
303 retval = flush_old_exec(bprm);
307 /* OK, This is the point of no return */
308 #if defined(__alpha__)
309 SET_AOUT_PERSONALITY(bprm, ex);
310 #elif defined(__sparc__)
311 set_personality(PER_SUNOS);
312 #if !defined(__sparc_v9__)
313 memcpy(¤t->thread.core_exec, &ex, sizeof(struct exec));
316 set_personality(PER_LINUX);
319 current->mm->end_code = ex.a_text +
320 (current->mm->start_code = N_TXTADDR(ex));
321 current->mm->end_data = ex.a_data +
322 (current->mm->start_data = N_DATADDR(ex));
323 current->mm->brk = ex.a_bss +
324 (current->mm->start_brk = N_BSSADDR(ex));
325 current->mm->free_area_cache = current->mm->mmap_base;
326 current->mm->cached_hole_size = 0;
328 current->mm->mmap = NULL;
330 current->flags &= ~PF_FORKNOEXEC;
332 if (N_MAGIC(ex) == NMAGIC) {
333 loff_t pos = fd_offset;
334 /* Fuck me plenty... */
336 down_write(¤t->mm->mmap_sem);
337 error = do_brk(N_TXTADDR(ex), ex.a_text);
338 up_write(¤t->mm->mmap_sem);
339 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
341 down_write(¤t->mm->mmap_sem);
342 error = do_brk(N_DATADDR(ex), ex.a_data);
343 up_write(¤t->mm->mmap_sem);
344 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
350 if (N_MAGIC(ex) == OMAGIC) {
351 unsigned long text_addr, map_size;
354 text_addr = N_TXTADDR(ex);
356 #if defined(__alpha__) || defined(__sparc__)
358 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
361 map_size = ex.a_text+ex.a_data;
363 down_write(¤t->mm->mmap_sem);
364 error = do_brk(text_addr & PAGE_MASK, map_size);
365 up_write(¤t->mm->mmap_sem);
366 if (error != (text_addr & PAGE_MASK)) {
367 send_sig(SIGKILL, current, 0);
371 error = bprm->file->f_op->read(bprm->file,
372 (char __user *)text_addr,
373 ex.a_text+ex.a_data, &pos);
374 if ((signed long)error < 0) {
375 send_sig(SIGKILL, current, 0);
379 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
381 static unsigned long error_time, error_time2;
382 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
383 (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
385 printk(KERN_NOTICE "executable not page aligned\n");
386 error_time2 = jiffies;
389 if ((fd_offset & ~PAGE_MASK) != 0 &&
390 (jiffies-error_time) > 5*HZ)
393 "fd_offset is not page aligned. Please convert program: %s\n",
394 bprm->file->f_path.dentry->d_name.name);
395 error_time = jiffies;
398 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
399 loff_t pos = fd_offset;
400 down_write(¤t->mm->mmap_sem);
401 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
402 up_write(¤t->mm->mmap_sem);
403 bprm->file->f_op->read(bprm->file,
404 (char __user *)N_TXTADDR(ex),
405 ex.a_text+ex.a_data, &pos);
406 flush_icache_range((unsigned long) N_TXTADDR(ex),
407 (unsigned long) N_TXTADDR(ex) +
408 ex.a_text+ex.a_data);
412 down_write(¤t->mm->mmap_sem);
413 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
414 PROT_READ | PROT_EXEC,
415 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
417 up_write(¤t->mm->mmap_sem);
419 if (error != N_TXTADDR(ex)) {
420 send_sig(SIGKILL, current, 0);
424 down_write(¤t->mm->mmap_sem);
425 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
426 PROT_READ | PROT_WRITE | PROT_EXEC,
427 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
428 fd_offset + ex.a_text);
429 up_write(¤t->mm->mmap_sem);
430 if (error != N_DATADDR(ex)) {
431 send_sig(SIGKILL, current, 0);
436 set_binfmt(&aout_format);
438 retval = set_brk(current->mm->start_brk, current->mm->brk);
440 send_sig(SIGKILL, current, 0);
444 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
446 /* Someone check-me: is this error path enough? */
447 send_sig(SIGKILL, current, 0);
451 current->mm->start_stack =
452 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
454 regs->gp = ex.a_gpvalue;
456 start_thread(regs, ex.a_entry, current->mm->start_stack);
460 static int load_aout_library(struct file *file)
462 struct inode * inode;
463 unsigned long bss, start_addr, len;
468 inode = file->f_path.dentry->d_inode;
471 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
472 if (error != sizeof(ex))
475 /* We come in here for the regular a.out style of shared libraries */
476 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
477 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
478 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
483 * Requires a mmap handler. This prevents people from using a.out
484 * as part of an exploit attack against /proc-related vulnerabilities.
486 if (!file->f_op || !file->f_op->mmap)
492 /* For QMAGIC, the starting address is 0x20 into the page. We mask
493 this off to get the starting address for the page */
495 start_addr = ex.a_entry & 0xfffff000;
497 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
498 static unsigned long error_time;
499 loff_t pos = N_TXTOFF(ex);
501 if ((jiffies-error_time) > 5*HZ)
504 "N_TXTOFF is not page aligned. Please convert library: %s\n",
505 file->f_path.dentry->d_name.name);
506 error_time = jiffies;
508 down_write(¤t->mm->mmap_sem);
509 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
510 up_write(¤t->mm->mmap_sem);
512 file->f_op->read(file, (char __user *)start_addr,
513 ex.a_text + ex.a_data, &pos);
514 flush_icache_range((unsigned long) start_addr,
515 (unsigned long) start_addr + ex.a_text + ex.a_data);
520 /* Now use mmap to map the library into memory. */
521 down_write(¤t->mm->mmap_sem);
522 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
523 PROT_READ | PROT_WRITE | PROT_EXEC,
524 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
526 up_write(¤t->mm->mmap_sem);
528 if (error != start_addr)
531 len = PAGE_ALIGN(ex.a_text + ex.a_data);
532 bss = ex.a_text + ex.a_data + ex.a_bss;
534 down_write(¤t->mm->mmap_sem);
535 error = do_brk(start_addr + len, bss - len);
536 up_write(¤t->mm->mmap_sem);
538 if (error != start_addr + len)
546 static int __init init_aout_binfmt(void)
548 return register_binfmt(&aout_format);
551 static void __exit exit_aout_binfmt(void)
553 unregister_binfmt(&aout_format);
556 core_initcall(init_aout_binfmt);
557 module_exit(exit_aout_binfmt);
558 MODULE_LICENSE("GPL");