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>
28 #include <asm/system.h>
29 #include <asm/uaccess.h>
30 #include <asm/cacheflush.h>
31 #include <asm/a.out-core.h>
33 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
34 static int load_aout_library(struct file*);
35 static int aout_core_dump(struct coredump_params *cprm);
37 static struct linux_binfmt aout_format = {
38 .module = THIS_MODULE,
39 .load_binary = load_aout_binary,
40 .load_shlib = load_aout_library,
41 .core_dump = aout_core_dump,
42 .min_coredump = PAGE_SIZE
45 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
47 static int set_brk(unsigned long start, unsigned long end)
49 start = PAGE_ALIGN(start);
50 end = PAGE_ALIGN(end);
53 down_write(¤t->mm->mmap_sem);
54 addr = do_brk(start, end - start);
55 up_write(¤t->mm->mmap_sem);
63 * These are the only things you should do on a core-file: use only these
64 * macros to write out all the necessary info.
67 static int dump_write(struct file *file, const void *addr, int nr)
69 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
72 #define DUMP_WRITE(addr, nr) \
73 if (!dump_write(file, (void *)(addr), (nr))) \
76 #define DUMP_SEEK(offset) \
77 if (file->f_op->llseek) { \
78 if (file->f_op->llseek(file,(offset),0) != (offset)) \
80 } else file->f_pos = (offset)
83 * Routine writes a core dump image in the current directory.
84 * Currently only a stub-function.
86 * Note that setuid/setgid files won't make a core-dump if the uid/gid
87 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
88 * field, which also makes sure the core-dumps won't be recursive if the
89 * dumping of the process results in another error..
92 static int aout_core_dump(struct coredump_params *cprm)
94 struct file *file = cprm->file;
97 unsigned long dump_start, dump_size;
100 # define START_DATA(u) (u.start_data)
102 # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
104 # define START_STACK(u) (u.start_stack)
109 current->flags |= PF_DUMPCORE;
110 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
111 dump.u_ar0 = offsetof(struct user, regs);
112 dump.signal = cprm->signr;
113 aout_dump_thread(cprm->regs, &dump);
115 /* If the size of the dump file exceeds the rlimit, then see what would happen
116 if we wrote the stack, but not the data area. */
117 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit)
120 /* Make sure we have enough room to write the stack and data areas. */
121 if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
124 /* make sure we actually have a data and stack area to dump */
126 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
128 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
133 DUMP_WRITE(&dump,sizeof(dump));
134 /* Now dump all of the user data. Include malloced stuff as well */
135 DUMP_SEEK(PAGE_SIZE);
136 /* now we start writing out the user space info */
138 /* Dump the data area */
139 if (dump.u_dsize != 0) {
140 dump_start = START_DATA(dump);
141 dump_size = dump.u_dsize << PAGE_SHIFT;
142 DUMP_WRITE(dump_start,dump_size);
144 /* Now prepare to dump the stack area */
145 if (dump.u_ssize != 0) {
146 dump_start = START_STACK(dump);
147 dump_size = dump.u_ssize << PAGE_SHIFT;
148 DUMP_WRITE(dump_start,dump_size);
150 /* Finally dump the task struct. Not be used by gdb, but could be useful */
152 DUMP_WRITE(current,sizeof(*current));
159 * create_aout_tables() parses the env- and arg-strings in new user
160 * memory and creates the pointer tables from them, and puts their
161 * addresses on the "stack", returning the new stack pointer value.
163 static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
165 char __user * __user *argv;
166 char __user * __user *envp;
167 unsigned long __user *sp;
168 int argc = bprm->argc;
169 int envc = bprm->envc;
171 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
173 /* whee.. test-programs are so much fun. */
178 put_user(1003, --sp);
179 put_user(bprm->loader, --sp);
180 put_user(1002, --sp);
182 put_user(bprm->exec, --sp);
183 put_user(1001, --sp);
186 envp = (char __user * __user *) sp;
188 argv = (char __user * __user *) sp;
190 put_user((unsigned long) envp,--sp);
191 put_user((unsigned long) argv,--sp);
194 current->mm->arg_start = (unsigned long) p;
203 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
212 current->mm->env_end = (unsigned long) p;
217 * These are the functions used to load a.out style executables and shared
218 * libraries. There is no binary dependent code anywhere else.
221 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
225 unsigned long fd_offset;
229 ex = *((struct exec *) bprm->buf); /* exec-header */
230 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
231 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
232 N_TRSIZE(ex) || N_DRSIZE(ex) ||
233 i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
238 * Requires a mmap handler. This prevents people from using a.out
239 * as part of an exploit attack against /proc-related vulnerabilities.
241 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
244 fd_offset = N_TXTOFF(ex);
246 /* Check initial limits. This avoids letting people circumvent
247 * size limits imposed on them by creating programs with large
248 * arrays in the data or bss.
250 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
251 if (rlim >= RLIM_INFINITY)
253 if (ex.a_data + ex.a_bss > rlim)
256 /* Flush all traces of the currently running executable */
257 retval = flush_old_exec(bprm);
261 /* OK, This is the point of no return */
263 SET_AOUT_PERSONALITY(bprm, ex);
265 set_personality(PER_LINUX);
268 current->mm->end_code = ex.a_text +
269 (current->mm->start_code = N_TXTADDR(ex));
270 current->mm->end_data = ex.a_data +
271 (current->mm->start_data = N_DATADDR(ex));
272 current->mm->brk = ex.a_bss +
273 (current->mm->start_brk = N_BSSADDR(ex));
274 current->mm->free_area_cache = current->mm->mmap_base;
275 current->mm->cached_hole_size = 0;
277 install_exec_creds(bprm);
278 current->flags &= ~PF_FORKNOEXEC;
280 if (N_MAGIC(ex) == OMAGIC) {
281 unsigned long text_addr, map_size;
284 text_addr = N_TXTADDR(ex);
288 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
291 map_size = ex.a_text+ex.a_data;
293 down_write(¤t->mm->mmap_sem);
294 error = do_brk(text_addr & PAGE_MASK, map_size);
295 up_write(¤t->mm->mmap_sem);
296 if (error != (text_addr & PAGE_MASK)) {
297 send_sig(SIGKILL, current, 0);
301 error = bprm->file->f_op->read(bprm->file,
302 (char __user *)text_addr,
303 ex.a_text+ex.a_data, &pos);
304 if ((signed long)error < 0) {
305 send_sig(SIGKILL, current, 0);
309 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
311 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
312 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
314 printk(KERN_NOTICE "executable not page aligned\n");
317 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
320 "fd_offset is not page aligned. Please convert program: %s\n",
321 bprm->file->f_path.dentry->d_name.name);
324 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
325 loff_t pos = fd_offset;
326 down_write(¤t->mm->mmap_sem);
327 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
328 up_write(¤t->mm->mmap_sem);
329 bprm->file->f_op->read(bprm->file,
330 (char __user *)N_TXTADDR(ex),
331 ex.a_text+ex.a_data, &pos);
332 flush_icache_range((unsigned long) N_TXTADDR(ex),
333 (unsigned long) N_TXTADDR(ex) +
334 ex.a_text+ex.a_data);
338 down_write(¤t->mm->mmap_sem);
339 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
340 PROT_READ | PROT_EXEC,
341 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
343 up_write(¤t->mm->mmap_sem);
345 if (error != N_TXTADDR(ex)) {
346 send_sig(SIGKILL, current, 0);
350 down_write(¤t->mm->mmap_sem);
351 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
352 PROT_READ | PROT_WRITE | PROT_EXEC,
353 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
354 fd_offset + ex.a_text);
355 up_write(¤t->mm->mmap_sem);
356 if (error != N_DATADDR(ex)) {
357 send_sig(SIGKILL, current, 0);
362 set_binfmt(&aout_format);
364 retval = set_brk(current->mm->start_brk, current->mm->brk);
366 send_sig(SIGKILL, current, 0);
370 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
372 /* Someone check-me: is this error path enough? */
373 send_sig(SIGKILL, current, 0);
377 current->mm->start_stack =
378 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
380 regs->gp = ex.a_gpvalue;
382 start_thread(regs, ex.a_entry, current->mm->start_stack);
386 static int load_aout_library(struct file *file)
388 struct inode * inode;
389 unsigned long bss, start_addr, len;
394 inode = file->f_path.dentry->d_inode;
397 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
398 if (error != sizeof(ex))
401 /* We come in here for the regular a.out style of shared libraries */
402 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
403 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
404 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
409 * Requires a mmap handler. This prevents people from using a.out
410 * as part of an exploit attack against /proc-related vulnerabilities.
412 if (!file->f_op || !file->f_op->mmap)
418 /* For QMAGIC, the starting address is 0x20 into the page. We mask
419 this off to get the starting address for the page */
421 start_addr = ex.a_entry & 0xfffff000;
423 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
424 loff_t pos = N_TXTOFF(ex);
426 if (printk_ratelimit())
429 "N_TXTOFF is not page aligned. Please convert library: %s\n",
430 file->f_path.dentry->d_name.name);
432 down_write(¤t->mm->mmap_sem);
433 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
434 up_write(¤t->mm->mmap_sem);
436 file->f_op->read(file, (char __user *)start_addr,
437 ex.a_text + ex.a_data, &pos);
438 flush_icache_range((unsigned long) start_addr,
439 (unsigned long) start_addr + ex.a_text + ex.a_data);
444 /* Now use mmap to map the library into memory. */
445 down_write(¤t->mm->mmap_sem);
446 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
447 PROT_READ | PROT_WRITE | PROT_EXEC,
448 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
450 up_write(¤t->mm->mmap_sem);
452 if (error != start_addr)
455 len = PAGE_ALIGN(ex.a_text + ex.a_data);
456 bss = ex.a_text + ex.a_data + ex.a_bss;
458 down_write(¤t->mm->mmap_sem);
459 error = do_brk(start_addr + len, bss - len);
460 up_write(¤t->mm->mmap_sem);
462 if (error != start_addr + len)
470 static int __init init_aout_binfmt(void)
472 return register_binfmt(&aout_format);
475 static void __exit exit_aout_binfmt(void)
477 unregister_binfmt(&aout_format);
480 core_initcall(init_aout_binfmt);
481 module_exit(exit_aout_binfmt);
482 MODULE_LICENSE("GPL");