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(long signr
, struct pt_regs
*regs
, struct file
*file
, unsigned long limit
);
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(long signr
, struct pt_regs
*regs
, struct file
*file
, unsigned long limit
)
96 unsigned long dump_start
, dump_size
;
99 # define START_DATA(u) (u.start_data)
101 # define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
103 # define START_STACK(u) (u.start_stack)
108 current
->flags
|= PF_DUMPCORE
;
109 strncpy(dump
.u_comm
, current
->comm
, sizeof(dump
.u_comm
));
110 dump
.u_ar0
= offsetof(struct user
, regs
);
112 aout_dump_thread(regs
, &dump
);
114 /* If the size of the dump file exceeds the rlimit, then see what would happen
115 if we wrote the stack, but not the data area. */
116 if ((dump
.u_dsize
+ dump
.u_ssize
+1) * PAGE_SIZE
> limit
)
119 /* Make sure we have enough room to write the stack and data areas. */
120 if ((dump
.u_ssize
+ 1) * PAGE_SIZE
> limit
)
123 /* make sure we actually have a data and stack area to dump */
125 if (!access_ok(VERIFY_READ
, (void __user
*)START_DATA(dump
), dump
.u_dsize
<< PAGE_SHIFT
))
127 if (!access_ok(VERIFY_READ
, (void __user
*)START_STACK(dump
), dump
.u_ssize
<< PAGE_SHIFT
))
132 DUMP_WRITE(&dump
,sizeof(dump
));
133 /* Now dump all of the user data. Include malloced stuff as well */
134 DUMP_SEEK(PAGE_SIZE
);
135 /* now we start writing out the user space info */
137 /* Dump the data area */
138 if (dump
.u_dsize
!= 0) {
139 dump_start
= START_DATA(dump
);
140 dump_size
= dump
.u_dsize
<< PAGE_SHIFT
;
141 DUMP_WRITE(dump_start
,dump_size
);
143 /* Now prepare to dump the stack area */
144 if (dump
.u_ssize
!= 0) {
145 dump_start
= START_STACK(dump
);
146 dump_size
= dump
.u_ssize
<< PAGE_SHIFT
;
147 DUMP_WRITE(dump_start
,dump_size
);
149 /* Finally dump the task struct. Not be used by gdb, but could be useful */
151 DUMP_WRITE(current
,sizeof(*current
));
158 * create_aout_tables() parses the env- and arg-strings in new user
159 * memory and creates the pointer tables from them, and puts their
160 * addresses on the "stack", returning the new stack pointer value.
162 static unsigned long __user
*create_aout_tables(char __user
*p
, struct linux_binprm
* bprm
)
164 char __user
* __user
*argv
;
165 char __user
* __user
*envp
;
166 unsigned long __user
*sp
;
167 int argc
= bprm
->argc
;
168 int envc
= bprm
->envc
;
170 sp
= (void __user
*)((-(unsigned long)sizeof(char *)) & (unsigned long) p
);
172 /* whee.. test-programs are so much fun. */
177 put_user(1003, --sp
);
178 put_user(bprm
->loader
, --sp
);
179 put_user(1002, --sp
);
181 put_user(bprm
->exec
, --sp
);
182 put_user(1001, --sp
);
185 envp
= (char __user
* __user
*) sp
;
187 argv
= (char __user
* __user
*) sp
;
189 put_user((unsigned long) envp
,--sp
);
190 put_user((unsigned long) argv
,--sp
);
193 current
->mm
->arg_start
= (unsigned long) p
;
202 current
->mm
->arg_end
= current
->mm
->env_start
= (unsigned long) p
;
211 current
->mm
->env_end
= (unsigned long) p
;
216 * These are the functions used to load a.out style executables and shared
217 * libraries. There is no binary dependent code anywhere else.
220 static int load_aout_binary(struct linux_binprm
* bprm
, struct pt_regs
* regs
)
224 unsigned long fd_offset
;
228 ex
= *((struct exec
*) bprm
->buf
); /* exec-header */
229 if ((N_MAGIC(ex
) != ZMAGIC
&& N_MAGIC(ex
) != OMAGIC
&&
230 N_MAGIC(ex
) != QMAGIC
&& N_MAGIC(ex
) != NMAGIC
) ||
231 N_TRSIZE(ex
) || N_DRSIZE(ex
) ||
232 i_size_read(bprm
->file
->f_path
.dentry
->d_inode
) < ex
.a_text
+ex
.a_data
+N_SYMSIZE(ex
)+N_TXTOFF(ex
)) {
237 * Requires a mmap handler. This prevents people from using a.out
238 * as part of an exploit attack against /proc-related vulnerabilities.
240 if (!bprm
->file
->f_op
|| !bprm
->file
->f_op
->mmap
)
243 fd_offset
= N_TXTOFF(ex
);
245 /* Check initial limits. This avoids letting people circumvent
246 * size limits imposed on them by creating programs with large
247 * arrays in the data or bss.
249 rlim
= current
->signal
->rlim
[RLIMIT_DATA
].rlim_cur
;
250 if (rlim
>= RLIM_INFINITY
)
252 if (ex
.a_data
+ ex
.a_bss
> rlim
)
255 /* Flush all traces of the currently running executable */
256 retval
= flush_old_exec(bprm
);
260 /* OK, This is the point of no return */
262 SET_AOUT_PERSONALITY(bprm
, ex
);
264 set_personality(PER_LINUX
);
267 current
->mm
->end_code
= ex
.a_text
+
268 (current
->mm
->start_code
= N_TXTADDR(ex
));
269 current
->mm
->end_data
= ex
.a_data
+
270 (current
->mm
->start_data
= N_DATADDR(ex
));
271 current
->mm
->brk
= ex
.a_bss
+
272 (current
->mm
->start_brk
= N_BSSADDR(ex
));
273 current
->mm
->free_area_cache
= current
->mm
->mmap_base
;
274 current
->mm
->cached_hole_size
= 0;
276 install_exec_creds(bprm
);
277 current
->flags
&= ~PF_FORKNOEXEC
;
279 if (N_MAGIC(ex
) == OMAGIC
) {
280 unsigned long text_addr
, map_size
;
283 text_addr
= N_TXTADDR(ex
);
287 map_size
= ex
.a_text
+ex
.a_data
+ PAGE_SIZE
- 1;
290 map_size
= ex
.a_text
+ex
.a_data
;
292 down_write(¤t
->mm
->mmap_sem
);
293 error
= do_brk(text_addr
& PAGE_MASK
, map_size
);
294 up_write(¤t
->mm
->mmap_sem
);
295 if (error
!= (text_addr
& PAGE_MASK
)) {
296 send_sig(SIGKILL
, current
, 0);
300 error
= bprm
->file
->f_op
->read(bprm
->file
,
301 (char __user
*)text_addr
,
302 ex
.a_text
+ex
.a_data
, &pos
);
303 if ((signed long)error
< 0) {
304 send_sig(SIGKILL
, current
, 0);
308 flush_icache_range(text_addr
, text_addr
+ex
.a_text
+ex
.a_data
);
310 if ((ex
.a_text
& 0xfff || ex
.a_data
& 0xfff) &&
311 (N_MAGIC(ex
) != NMAGIC
) && printk_ratelimit())
313 printk(KERN_NOTICE
"executable not page aligned\n");
316 if ((fd_offset
& ~PAGE_MASK
) != 0 && printk_ratelimit())
319 "fd_offset is not page aligned. Please convert program: %s\n",
320 bprm
->file
->f_path
.dentry
->d_name
.name
);
323 if (!bprm
->file
->f_op
->mmap
||((fd_offset
& ~PAGE_MASK
) != 0)) {
324 loff_t pos
= fd_offset
;
325 down_write(¤t
->mm
->mmap_sem
);
326 do_brk(N_TXTADDR(ex
), ex
.a_text
+ex
.a_data
);
327 up_write(¤t
->mm
->mmap_sem
);
328 bprm
->file
->f_op
->read(bprm
->file
,
329 (char __user
*)N_TXTADDR(ex
),
330 ex
.a_text
+ex
.a_data
, &pos
);
331 flush_icache_range((unsigned long) N_TXTADDR(ex
),
332 (unsigned long) N_TXTADDR(ex
) +
333 ex
.a_text
+ex
.a_data
);
337 down_write(¤t
->mm
->mmap_sem
);
338 error
= do_mmap(bprm
->file
, N_TXTADDR(ex
), ex
.a_text
,
339 PROT_READ
| PROT_EXEC
,
340 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
| MAP_EXECUTABLE
,
342 up_write(¤t
->mm
->mmap_sem
);
344 if (error
!= N_TXTADDR(ex
)) {
345 send_sig(SIGKILL
, current
, 0);
349 down_write(¤t
->mm
->mmap_sem
);
350 error
= do_mmap(bprm
->file
, N_DATADDR(ex
), ex
.a_data
,
351 PROT_READ
| PROT_WRITE
| PROT_EXEC
,
352 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
| MAP_EXECUTABLE
,
353 fd_offset
+ ex
.a_text
);
354 up_write(¤t
->mm
->mmap_sem
);
355 if (error
!= N_DATADDR(ex
)) {
356 send_sig(SIGKILL
, current
, 0);
361 set_binfmt(&aout_format
);
363 retval
= set_brk(current
->mm
->start_brk
, current
->mm
->brk
);
365 send_sig(SIGKILL
, current
, 0);
369 retval
= setup_arg_pages(bprm
, STACK_TOP
, EXSTACK_DEFAULT
);
371 /* Someone check-me: is this error path enough? */
372 send_sig(SIGKILL
, current
, 0);
376 current
->mm
->start_stack
=
377 (unsigned long) create_aout_tables((char __user
*) bprm
->p
, bprm
);
379 regs
->gp
= ex
.a_gpvalue
;
381 start_thread(regs
, ex
.a_entry
, current
->mm
->start_stack
);
385 static int load_aout_library(struct file
*file
)
387 struct inode
* inode
;
388 unsigned long bss
, start_addr
, len
;
393 inode
= file
->f_path
.dentry
->d_inode
;
396 error
= kernel_read(file
, 0, (char *) &ex
, sizeof(ex
));
397 if (error
!= sizeof(ex
))
400 /* We come in here for the regular a.out style of shared libraries */
401 if ((N_MAGIC(ex
) != ZMAGIC
&& N_MAGIC(ex
) != QMAGIC
) || N_TRSIZE(ex
) ||
402 N_DRSIZE(ex
) || ((ex
.a_entry
& 0xfff) && N_MAGIC(ex
) == ZMAGIC
) ||
403 i_size_read(inode
) < ex
.a_text
+ex
.a_data
+N_SYMSIZE(ex
)+N_TXTOFF(ex
)) {
408 * Requires a mmap handler. This prevents people from using a.out
409 * as part of an exploit attack against /proc-related vulnerabilities.
411 if (!file
->f_op
|| !file
->f_op
->mmap
)
417 /* For QMAGIC, the starting address is 0x20 into the page. We mask
418 this off to get the starting address for the page */
420 start_addr
= ex
.a_entry
& 0xfffff000;
422 if ((N_TXTOFF(ex
) & ~PAGE_MASK
) != 0) {
423 loff_t pos
= N_TXTOFF(ex
);
425 if (printk_ratelimit())
428 "N_TXTOFF is not page aligned. Please convert library: %s\n",
429 file
->f_path
.dentry
->d_name
.name
);
431 down_write(¤t
->mm
->mmap_sem
);
432 do_brk(start_addr
, ex
.a_text
+ ex
.a_data
+ ex
.a_bss
);
433 up_write(¤t
->mm
->mmap_sem
);
435 file
->f_op
->read(file
, (char __user
*)start_addr
,
436 ex
.a_text
+ ex
.a_data
, &pos
);
437 flush_icache_range((unsigned long) start_addr
,
438 (unsigned long) start_addr
+ ex
.a_text
+ ex
.a_data
);
443 /* Now use mmap to map the library into memory. */
444 down_write(¤t
->mm
->mmap_sem
);
445 error
= do_mmap(file
, start_addr
, ex
.a_text
+ ex
.a_data
,
446 PROT_READ
| PROT_WRITE
| PROT_EXEC
,
447 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
,
449 up_write(¤t
->mm
->mmap_sem
);
451 if (error
!= start_addr
)
454 len
= PAGE_ALIGN(ex
.a_text
+ ex
.a_data
);
455 bss
= ex
.a_text
+ ex
.a_data
+ ex
.a_bss
;
457 down_write(¤t
->mm
->mmap_sem
);
458 error
= do_brk(start_addr
+ len
, bss
- len
);
459 up_write(¤t
->mm
->mmap_sem
);
461 if (error
!= start_addr
+ len
)
469 static int __init
init_aout_binfmt(void)
471 return register_binfmt(&aout_format
);
474 static void __exit
exit_aout_binfmt(void)
476 unregister_binfmt(&aout_format
);
479 core_initcall(init_aout_binfmt
);
480 module_exit(exit_aout_binfmt
);
481 MODULE_LICENSE("GPL");
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