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1/*
2 * linux/fs/binfmt_aout.c
3 *
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
5 */
6
7#include <linux/module.h>
8
9#include <linux/time.h>
10#include <linux/kernel.h>
11#include <linux/mm.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>
17#include <linux/fs.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>
28#include <linux/sched/task_stack.h>
29
30#include <linux/uaccess.h>
31#include <asm/cacheflush.h>
32
33static int load_aout_binary(struct linux_binprm *);
34static int load_aout_library(struct file*);
35
36static struct linux_binfmt aout_format = {
37 .module = THIS_MODULE,
38 .load_binary = load_aout_binary,
39 .load_shlib = load_aout_library,
40};
41
42#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
43
44static int set_brk(unsigned long start, unsigned long end)
45{
46 start = PAGE_ALIGN(start);
47 end = PAGE_ALIGN(end);
48 if (end > start)
49 return vm_brk(start, end - start);
50 return 0;
51}
52
53/*
54 * create_aout_tables() parses the env- and arg-strings in new user
55 * memory and creates the pointer tables from them, and puts their
56 * addresses on the "stack", returning the new stack pointer value.
57 */
58static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
59{
60 char __user * __user *argv;
61 char __user * __user *envp;
62 unsigned long __user *sp;
63 int argc = bprm->argc;
64 int envc = bprm->envc;
65
66 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
67#ifdef __alpha__
68/* whee.. test-programs are so much fun. */
69 put_user(0, --sp);
70 put_user(0, --sp);
71 if (bprm->loader) {
72 put_user(0, --sp);
73 put_user(1003, --sp);
74 put_user(bprm->loader, --sp);
75 put_user(1002, --sp);
76 }
77 put_user(bprm->exec, --sp);
78 put_user(1001, --sp);
79#endif
80 sp -= envc+1;
81 envp = (char __user * __user *) sp;
82 sp -= argc+1;
83 argv = (char __user * __user *) sp;
84#ifndef __alpha__
85 put_user((unsigned long) envp,--sp);
86 put_user((unsigned long) argv,--sp);
87#endif
88 put_user(argc,--sp);
89 current->mm->arg_start = (unsigned long) p;
90 while (argc-->0) {
91 char c;
92 put_user(p,argv++);
93 do {
94 get_user(c,p++);
95 } while (c);
96 }
97 put_user(NULL,argv);
98 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
99 while (envc-->0) {
100 char c;
101 put_user(p,envp++);
102 do {
103 get_user(c,p++);
104 } while (c);
105 }
106 put_user(NULL,envp);
107 current->mm->env_end = (unsigned long) p;
108 return sp;
109}
110
111/*
112 * These are the functions used to load a.out style executables and shared
113 * libraries. There is no binary dependent code anywhere else.
114 */
115
116static int load_aout_binary(struct linux_binprm * bprm)
117{
118 struct pt_regs *regs = current_pt_regs();
119 struct exec ex;
120 unsigned long error;
121 unsigned long fd_offset;
122 unsigned long rlim;
123 int retval;
124
125 ex = *((struct exec *) bprm->buf); /* exec-header */
126 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
127 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
128 N_TRSIZE(ex) || N_DRSIZE(ex) ||
129 i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
130 return -ENOEXEC;
131 }
132
133 /*
134 * Requires a mmap handler. This prevents people from using a.out
135 * as part of an exploit attack against /proc-related vulnerabilities.
136 */
137 if (!bprm->file->f_op->mmap)
138 return -ENOEXEC;
139
140 fd_offset = N_TXTOFF(ex);
141
142 /* Check initial limits. This avoids letting people circumvent
143 * size limits imposed on them by creating programs with large
144 * arrays in the data or bss.
145 */
146 rlim = rlimit(RLIMIT_DATA);
147 if (rlim >= RLIM_INFINITY)
148 rlim = ~0;
149 if (ex.a_data + ex.a_bss > rlim)
150 return -ENOMEM;
151
152 /* Flush all traces of the currently running executable */
153 retval = flush_old_exec(bprm);
154 if (retval)
155 return retval;
156
157 /* OK, This is the point of no return */
158#ifdef __alpha__
159 SET_AOUT_PERSONALITY(bprm, ex);
160#else
161 set_personality(PER_LINUX);
162#endif
163 setup_new_exec(bprm);
164
165 current->mm->end_code = ex.a_text +
166 (current->mm->start_code = N_TXTADDR(ex));
167 current->mm->end_data = ex.a_data +
168 (current->mm->start_data = N_DATADDR(ex));
169 current->mm->brk = ex.a_bss +
170 (current->mm->start_brk = N_BSSADDR(ex));
171
172 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
173 if (retval < 0)
174 return retval;
175
176 install_exec_creds(bprm);
177
178 if (N_MAGIC(ex) == OMAGIC) {
179 unsigned long text_addr, map_size;
180 loff_t pos;
181
182 text_addr = N_TXTADDR(ex);
183
184#ifdef __alpha__
185 pos = fd_offset;
186 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
187#else
188 pos = 32;
189 map_size = ex.a_text+ex.a_data;
190#endif
191 error = vm_brk(text_addr & PAGE_MASK, map_size);
192 if (error)
193 return error;
194
195 error = read_code(bprm->file, text_addr, pos,
196 ex.a_text+ex.a_data);
197 if ((signed long)error < 0)
198 return error;
199 } else {
200 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
201 (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
202 {
203 printk(KERN_NOTICE "executable not page aligned\n");
204 }
205
206 if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
207 {
208 printk(KERN_WARNING
209 "fd_offset is not page aligned. Please convert program: %pD\n",
210 bprm->file);
211 }
212
213 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
214 error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
215 if (error)
216 return error;
217
218 read_code(bprm->file, N_TXTADDR(ex), fd_offset,
219 ex.a_text + ex.a_data);
220 goto beyond_if;
221 }
222
223 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
224 PROT_READ | PROT_EXEC,
225 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
226 fd_offset);
227
228 if (error != N_TXTADDR(ex))
229 return error;
230
231 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
232 PROT_READ | PROT_WRITE | PROT_EXEC,
233 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
234 fd_offset + ex.a_text);
235 if (error != N_DATADDR(ex))
236 return error;
237 }
238beyond_if:
239 set_binfmt(&aout_format);
240
241 retval = set_brk(current->mm->start_brk, current->mm->brk);
242 if (retval < 0)
243 return retval;
244
245 current->mm->start_stack =
246 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
247#ifdef __alpha__
248 regs->gp = ex.a_gpvalue;
249#endif
250 finalize_exec(bprm);
251 start_thread(regs, ex.a_entry, current->mm->start_stack);
252 return 0;
253}
254
255static int load_aout_library(struct file *file)
256{
257 struct inode * inode;
258 unsigned long bss, start_addr, len;
259 unsigned long error;
260 int retval;
261 struct exec ex;
262 loff_t pos = 0;
263
264 inode = file_inode(file);
265
266 retval = -ENOEXEC;
267 error = kernel_read(file, &ex, sizeof(ex), &pos);
268 if (error != sizeof(ex))
269 goto out;
270
271 /* We come in here for the regular a.out style of shared libraries */
272 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
273 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
274 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
275 goto out;
276 }
277
278 /*
279 * Requires a mmap handler. This prevents people from using a.out
280 * as part of an exploit attack against /proc-related vulnerabilities.
281 */
282 if (!file->f_op->mmap)
283 goto out;
284
285 if (N_FLAGS(ex))
286 goto out;
287
288 /* For QMAGIC, the starting address is 0x20 into the page. We mask
289 this off to get the starting address for the page */
290
291 start_addr = ex.a_entry & 0xfffff000;
292
293 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
294 if (printk_ratelimit())
295 {
296 printk(KERN_WARNING
297 "N_TXTOFF is not page aligned. Please convert library: %pD\n",
298 file);
299 }
300 retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
301 if (retval)
302 goto out;
303
304 read_code(file, start_addr, N_TXTOFF(ex),
305 ex.a_text + ex.a_data);
306 retval = 0;
307 goto out;
308 }
309 /* Now use mmap to map the library into memory. */
310 error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
311 PROT_READ | PROT_WRITE | PROT_EXEC,
312 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
313 N_TXTOFF(ex));
314 retval = error;
315 if (error != start_addr)
316 goto out;
317
318 len = PAGE_ALIGN(ex.a_text + ex.a_data);
319 bss = ex.a_text + ex.a_data + ex.a_bss;
320 if (bss > len) {
321 retval = vm_brk(start_addr + len, bss - len);
322 if (retval)
323 goto out;
324 }
325 retval = 0;
326out:
327 return retval;
328}
329
330static int __init init_aout_binfmt(void)
331{
332 register_binfmt(&aout_format);
333 return 0;
334}
335
336static void __exit exit_aout_binfmt(void)
337{
338 unregister_binfmt(&aout_format);
339}
340
341core_initcall(init_aout_binfmt);
342module_exit(exit_aout_binfmt);
343MODULE_LICENSE("GPL");
344

Warning: That file was not part of the compilation database. It may have many parsing errors.