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/binfmts.h>
24 #include <linux/personality.h>
25 #include <linux/init.h>
26 #include <linux/coredump.h>
27 #include <linux/slab.h>
29 #include <asm/system.h>
30 #include <asm/uaccess.h>
31 #include <asm/cacheflush.h>
32 #include <asm/a.out-core.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(struct coredump_params
*cprm
);
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 * Routine writes a core dump image in the current directory.
65 * Currently only a stub-function.
67 * Note that setuid/setgid files won't make a core-dump if the uid/gid
68 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
69 * field, which also makes sure the core-dumps won't be recursive if the
70 * dumping of the process results in another error..
73 static int aout_core_dump(struct coredump_params
*cprm
)
75 struct file
*file
= cprm
->file
;
78 void __user
*dump_start
;
82 # define START_DATA(u) ((void __user *)u.start_data)
84 # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \
87 # define START_STACK(u) ((void __user *)u.start_stack)
92 current
->flags
|= PF_DUMPCORE
;
93 strncpy(dump
.u_comm
, current
->comm
, sizeof(dump
.u_comm
));
94 dump
.u_ar0
= offsetof(struct user
, regs
);
95 dump
.signal
= cprm
->signr
;
96 aout_dump_thread(cprm
->regs
, &dump
);
98 /* If the size of the dump file exceeds the rlimit, then see what would happen
99 if we wrote the stack, but not the data area. */
100 if ((dump
.u_dsize
+ dump
.u_ssize
+1) * PAGE_SIZE
> cprm
->limit
)
103 /* Make sure we have enough room to write the stack and data areas. */
104 if ((dump
.u_ssize
+ 1) * PAGE_SIZE
> cprm
->limit
)
107 /* make sure we actually have a data and stack area to dump */
109 if (!access_ok(VERIFY_READ
, START_DATA(dump
), dump
.u_dsize
<< PAGE_SHIFT
))
111 if (!access_ok(VERIFY_READ
, START_STACK(dump
), dump
.u_ssize
<< PAGE_SHIFT
))
116 if (!dump_write(file
, &dump
, sizeof(dump
)))
118 /* Now dump all of the user data. Include malloced stuff as well */
119 if (!dump_seek(cprm
->file
, PAGE_SIZE
- sizeof(dump
)))
121 /* now we start writing out the user space info */
123 /* Dump the data area */
124 if (dump
.u_dsize
!= 0) {
125 dump_start
= START_DATA(dump
);
126 dump_size
= dump
.u_dsize
<< PAGE_SHIFT
;
127 if (!dump_write(file
, dump_start
, dump_size
))
130 /* Now prepare to dump the stack area */
131 if (dump
.u_ssize
!= 0) {
132 dump_start
= START_STACK(dump
);
133 dump_size
= dump
.u_ssize
<< PAGE_SHIFT
;
134 if (!dump_write(file
, dump_start
, dump_size
))
143 * create_aout_tables() parses the env- and arg-strings in new user
144 * memory and creates the pointer tables from them, and puts their
145 * addresses on the "stack", returning the new stack pointer value.
147 static unsigned long __user
*create_aout_tables(char __user
*p
, struct linux_binprm
* bprm
)
149 char __user
* __user
*argv
;
150 char __user
* __user
*envp
;
151 unsigned long __user
*sp
;
152 int argc
= bprm
->argc
;
153 int envc
= bprm
->envc
;
155 sp
= (void __user
*)((-(unsigned long)sizeof(char *)) & (unsigned long) p
);
157 /* whee.. test-programs are so much fun. */
162 put_user(1003, --sp
);
163 put_user(bprm
->loader
, --sp
);
164 put_user(1002, --sp
);
166 put_user(bprm
->exec
, --sp
);
167 put_user(1001, --sp
);
170 envp
= (char __user
* __user
*) sp
;
172 argv
= (char __user
* __user
*) sp
;
174 put_user((unsigned long) envp
,--sp
);
175 put_user((unsigned long) argv
,--sp
);
178 current
->mm
->arg_start
= (unsigned long) p
;
187 current
->mm
->arg_end
= current
->mm
->env_start
= (unsigned long) p
;
196 current
->mm
->env_end
= (unsigned long) p
;
201 * These are the functions used to load a.out style executables and shared
202 * libraries. There is no binary dependent code anywhere else.
205 static int load_aout_binary(struct linux_binprm
* bprm
, struct pt_regs
* regs
)
209 unsigned long fd_offset
;
213 ex
= *((struct exec
*) bprm
->buf
); /* exec-header */
214 if ((N_MAGIC(ex
) != ZMAGIC
&& N_MAGIC(ex
) != OMAGIC
&&
215 N_MAGIC(ex
) != QMAGIC
&& N_MAGIC(ex
) != NMAGIC
) ||
216 N_TRSIZE(ex
) || N_DRSIZE(ex
) ||
217 i_size_read(bprm
->file
->f_path
.dentry
->d_inode
) < ex
.a_text
+ex
.a_data
+N_SYMSIZE(ex
)+N_TXTOFF(ex
)) {
222 * Requires a mmap handler. This prevents people from using a.out
223 * as part of an exploit attack against /proc-related vulnerabilities.
225 if (!bprm
->file
->f_op
|| !bprm
->file
->f_op
->mmap
)
228 fd_offset
= N_TXTOFF(ex
);
230 /* Check initial limits. This avoids letting people circumvent
231 * size limits imposed on them by creating programs with large
232 * arrays in the data or bss.
234 rlim
= rlimit(RLIMIT_DATA
);
235 if (rlim
>= RLIM_INFINITY
)
237 if (ex
.a_data
+ ex
.a_bss
> rlim
)
240 /* Flush all traces of the currently running executable */
241 retval
= flush_old_exec(bprm
);
245 /* OK, This is the point of no return */
247 SET_AOUT_PERSONALITY(bprm
, ex
);
249 set_personality(PER_LINUX
);
251 setup_new_exec(bprm
);
253 current
->mm
->end_code
= ex
.a_text
+
254 (current
->mm
->start_code
= N_TXTADDR(ex
));
255 current
->mm
->end_data
= ex
.a_data
+
256 (current
->mm
->start_data
= N_DATADDR(ex
));
257 current
->mm
->brk
= ex
.a_bss
+
258 (current
->mm
->start_brk
= N_BSSADDR(ex
));
259 current
->mm
->free_area_cache
= current
->mm
->mmap_base
;
260 current
->mm
->cached_hole_size
= 0;
262 install_exec_creds(bprm
);
263 current
->flags
&= ~PF_FORKNOEXEC
;
265 if (N_MAGIC(ex
) == OMAGIC
) {
266 unsigned long text_addr
, map_size
;
269 text_addr
= N_TXTADDR(ex
);
273 map_size
= ex
.a_text
+ex
.a_data
+ PAGE_SIZE
- 1;
276 map_size
= ex
.a_text
+ex
.a_data
;
278 down_write(¤t
->mm
->mmap_sem
);
279 error
= do_brk(text_addr
& PAGE_MASK
, map_size
);
280 up_write(¤t
->mm
->mmap_sem
);
281 if (error
!= (text_addr
& PAGE_MASK
)) {
282 send_sig(SIGKILL
, current
, 0);
286 error
= bprm
->file
->f_op
->read(bprm
->file
,
287 (char __user
*)text_addr
,
288 ex
.a_text
+ex
.a_data
, &pos
);
289 if ((signed long)error
< 0) {
290 send_sig(SIGKILL
, current
, 0);
294 flush_icache_range(text_addr
, text_addr
+ex
.a_text
+ex
.a_data
);
296 if ((ex
.a_text
& 0xfff || ex
.a_data
& 0xfff) &&
297 (N_MAGIC(ex
) != NMAGIC
) && printk_ratelimit())
299 printk(KERN_NOTICE
"executable not page aligned\n");
302 if ((fd_offset
& ~PAGE_MASK
) != 0 && printk_ratelimit())
305 "fd_offset is not page aligned. Please convert program: %s\n",
306 bprm
->file
->f_path
.dentry
->d_name
.name
);
309 if (!bprm
->file
->f_op
->mmap
||((fd_offset
& ~PAGE_MASK
) != 0)) {
310 loff_t pos
= fd_offset
;
311 down_write(¤t
->mm
->mmap_sem
);
312 do_brk(N_TXTADDR(ex
), ex
.a_text
+ex
.a_data
);
313 up_write(¤t
->mm
->mmap_sem
);
314 bprm
->file
->f_op
->read(bprm
->file
,
315 (char __user
*)N_TXTADDR(ex
),
316 ex
.a_text
+ex
.a_data
, &pos
);
317 flush_icache_range((unsigned long) N_TXTADDR(ex
),
318 (unsigned long) N_TXTADDR(ex
) +
319 ex
.a_text
+ex
.a_data
);
323 down_write(¤t
->mm
->mmap_sem
);
324 error
= do_mmap(bprm
->file
, N_TXTADDR(ex
), ex
.a_text
,
325 PROT_READ
| PROT_EXEC
,
326 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
| MAP_EXECUTABLE
,
328 up_write(¤t
->mm
->mmap_sem
);
330 if (error
!= N_TXTADDR(ex
)) {
331 send_sig(SIGKILL
, current
, 0);
335 down_write(¤t
->mm
->mmap_sem
);
336 error
= do_mmap(bprm
->file
, N_DATADDR(ex
), ex
.a_data
,
337 PROT_READ
| PROT_WRITE
| PROT_EXEC
,
338 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
| MAP_EXECUTABLE
,
339 fd_offset
+ ex
.a_text
);
340 up_write(¤t
->mm
->mmap_sem
);
341 if (error
!= N_DATADDR(ex
)) {
342 send_sig(SIGKILL
, current
, 0);
347 set_binfmt(&aout_format
);
349 retval
= set_brk(current
->mm
->start_brk
, current
->mm
->brk
);
351 send_sig(SIGKILL
, current
, 0);
355 retval
= setup_arg_pages(bprm
, STACK_TOP
, EXSTACK_DEFAULT
);
357 /* Someone check-me: is this error path enough? */
358 send_sig(SIGKILL
, current
, 0);
362 current
->mm
->start_stack
=
363 (unsigned long) create_aout_tables((char __user
*) bprm
->p
, bprm
);
365 regs
->gp
= ex
.a_gpvalue
;
367 start_thread(regs
, ex
.a_entry
, current
->mm
->start_stack
);
371 static int load_aout_library(struct file
*file
)
373 struct inode
* inode
;
374 unsigned long bss
, start_addr
, len
;
379 inode
= file
->f_path
.dentry
->d_inode
;
382 error
= kernel_read(file
, 0, (char *) &ex
, sizeof(ex
));
383 if (error
!= sizeof(ex
))
386 /* We come in here for the regular a.out style of shared libraries */
387 if ((N_MAGIC(ex
) != ZMAGIC
&& N_MAGIC(ex
) != QMAGIC
) || N_TRSIZE(ex
) ||
388 N_DRSIZE(ex
) || ((ex
.a_entry
& 0xfff) && N_MAGIC(ex
) == ZMAGIC
) ||
389 i_size_read(inode
) < ex
.a_text
+ex
.a_data
+N_SYMSIZE(ex
)+N_TXTOFF(ex
)) {
394 * Requires a mmap handler. This prevents people from using a.out
395 * as part of an exploit attack against /proc-related vulnerabilities.
397 if (!file
->f_op
|| !file
->f_op
->mmap
)
403 /* For QMAGIC, the starting address is 0x20 into the page. We mask
404 this off to get the starting address for the page */
406 start_addr
= ex
.a_entry
& 0xfffff000;
408 if ((N_TXTOFF(ex
) & ~PAGE_MASK
) != 0) {
409 loff_t pos
= N_TXTOFF(ex
);
411 if (printk_ratelimit())
414 "N_TXTOFF is not page aligned. Please convert library: %s\n",
415 file
->f_path
.dentry
->d_name
.name
);
417 down_write(¤t
->mm
->mmap_sem
);
418 do_brk(start_addr
, ex
.a_text
+ ex
.a_data
+ ex
.a_bss
);
419 up_write(¤t
->mm
->mmap_sem
);
421 file
->f_op
->read(file
, (char __user
*)start_addr
,
422 ex
.a_text
+ ex
.a_data
, &pos
);
423 flush_icache_range((unsigned long) start_addr
,
424 (unsigned long) start_addr
+ ex
.a_text
+ ex
.a_data
);
429 /* Now use mmap to map the library into memory. */
430 down_write(¤t
->mm
->mmap_sem
);
431 error
= do_mmap(file
, start_addr
, ex
.a_text
+ ex
.a_data
,
432 PROT_READ
| PROT_WRITE
| PROT_EXEC
,
433 MAP_FIXED
| MAP_PRIVATE
| MAP_DENYWRITE
,
435 up_write(¤t
->mm
->mmap_sem
);
437 if (error
!= start_addr
)
440 len
= PAGE_ALIGN(ex
.a_text
+ ex
.a_data
);
441 bss
= ex
.a_text
+ ex
.a_data
+ ex
.a_bss
;
443 down_write(¤t
->mm
->mmap_sem
);
444 error
= do_brk(start_addr
+ len
, bss
- len
);
445 up_write(¤t
->mm
->mmap_sem
);
447 if (error
!= start_addr
+ len
)
455 static int __init
init_aout_binfmt(void)
457 return register_binfmt(&aout_format
);
460 static void __exit
exit_aout_binfmt(void)
462 unregister_binfmt(&aout_format
);
465 core_initcall(init_aout_binfmt
);
466 module_exit(exit_aout_binfmt
);
467 MODULE_LICENSE("GPL");
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