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TOMOYO Linux Cross Reference
Linux/arch/x86/ia32/ia32_aout.c

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  1 /*
  2  *  a.out loader for x86-64
  3  *
  4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
  5  *  Hacked together by Andi Kleen
  6  */
  7 
  8 #include <linux/module.h>
  9 
 10 #include <linux/time.h>
 11 #include <linux/kernel.h>
 12 #include <linux/mm.h>
 13 #include <linux/mman.h>
 14 #include <linux/a.out.h>
 15 #include <linux/errno.h>
 16 #include <linux/signal.h>
 17 #include <linux/string.h>
 18 #include <linux/fs.h>
 19 #include <linux/file.h>
 20 #include <linux/stat.h>
 21 #include <linux/fcntl.h>
 22 #include <linux/ptrace.h>
 23 #include <linux/user.h>
 24 #include <linux/binfmts.h>
 25 #include <linux/personality.h>
 26 #include <linux/init.h>
 27 #include <linux/jiffies.h>
 28 #include <linux/perf_event.h>
 29 
 30 #include <asm/uaccess.h>
 31 #include <asm/pgalloc.h>
 32 #include <asm/cacheflush.h>
 33 #include <asm/user32.h>
 34 #include <asm/ia32.h>
 35 
 36 #undef WARN_OLD
 37 
 38 static int load_aout_binary(struct linux_binprm *);
 39 static int load_aout_library(struct file *);
 40 
 41 #ifdef CONFIG_COREDUMP
 42 static int aout_core_dump(struct coredump_params *);
 43 
 44 static unsigned long get_dr(int n)
 45 {
 46         struct perf_event *bp = current->thread.ptrace_bps[n];
 47         return bp ? bp->hw.info.address : 0;
 48 }
 49 
 50 /*
 51  * fill in the user structure for a core dump..
 52  */
 53 static void fill_dump(struct pt_regs *regs, struct user32 *dump)
 54 {
 55         u32 fs, gs;
 56         memset(dump, 0, sizeof(*dump));
 57 
 58 /* changed the size calculations - should hopefully work better. lbt */
 59         dump->magic = CMAGIC;
 60         dump->start_code = 0;
 61         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
 62         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 63         dump->u_dsize = ((unsigned long)
 64                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
 65         dump->u_dsize -= dump->u_tsize;
 66         dump->u_debugreg[0] = get_dr(0);
 67         dump->u_debugreg[1] = get_dr(1);
 68         dump->u_debugreg[2] = get_dr(2);
 69         dump->u_debugreg[3] = get_dr(3);
 70         dump->u_debugreg[6] = current->thread.debugreg6;
 71         dump->u_debugreg[7] = current->thread.ptrace_dr7;
 72 
 73         if (dump->start_stack < 0xc0000000) {
 74                 unsigned long tmp;
 75 
 76                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
 77                 dump->u_ssize = tmp >> PAGE_SHIFT;
 78         }
 79 
 80         dump->regs.ebx = regs->bx;
 81         dump->regs.ecx = regs->cx;
 82         dump->regs.edx = regs->dx;
 83         dump->regs.esi = regs->si;
 84         dump->regs.edi = regs->di;
 85         dump->regs.ebp = regs->bp;
 86         dump->regs.eax = regs->ax;
 87         dump->regs.ds = current->thread.ds;
 88         dump->regs.es = current->thread.es;
 89         savesegment(fs, fs);
 90         dump->regs.fs = fs;
 91         savesegment(gs, gs);
 92         dump->regs.gs = gs;
 93         dump->regs.orig_eax = regs->orig_ax;
 94         dump->regs.eip = regs->ip;
 95         dump->regs.cs = regs->cs;
 96         dump->regs.eflags = regs->flags;
 97         dump->regs.esp = regs->sp;
 98         dump->regs.ss = regs->ss;
 99 
100 #if 1 /* FIXME */
101         dump->u_fpvalid = 0;
102 #else
103         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
104 #endif
105 }
106 
107 #endif
108 
109 static struct linux_binfmt aout_format = {
110         .module         = THIS_MODULE,
111         .load_binary    = load_aout_binary,
112         .load_shlib     = load_aout_library,
113 #ifdef CONFIG_COREDUMP
114         .core_dump      = aout_core_dump,
115 #endif
116         .min_coredump   = PAGE_SIZE
117 };
118 
119 static void set_brk(unsigned long start, unsigned long end)
120 {
121         start = PAGE_ALIGN(start);
122         end = PAGE_ALIGN(end);
123         if (end <= start)
124                 return;
125         vm_brk(start, end - start);
126 }
127 
128 #ifdef CONFIG_COREDUMP
129 /*
130  * These are the only things you should do on a core-file: use only these
131  * macros to write out all the necessary info.
132  */
133 
134 #include <linux/coredump.h>
135 
136 #define START_DATA(u)   (u.u_tsize << PAGE_SHIFT)
137 #define START_STACK(u)  (u.start_stack)
138 
139 /*
140  * Routine writes a core dump image in the current directory.
141  * Currently only a stub-function.
142  *
143  * Note that setuid/setgid files won't make a core-dump if the uid/gid
144  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
145  * field, which also makes sure the core-dumps won't be recursive if the
146  * dumping of the process results in another error..
147  */
148 
149 static int aout_core_dump(struct coredump_params *cprm)
150 {
151         mm_segment_t fs;
152         int has_dumped = 0;
153         unsigned long dump_start, dump_size;
154         struct user32 dump;
155 
156         fs = get_fs();
157         set_fs(KERNEL_DS);
158         has_dumped = 1;
159 
160         fill_dump(cprm->regs, &dump);
161 
162         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
163         dump.u_ar0 = offsetof(struct user32, regs);
164         dump.signal = cprm->siginfo->si_signo;
165 
166         /*
167          * If the size of the dump file exceeds the rlimit, then see
168          * what would happen if we wrote the stack, but not the data
169          * area.
170          */
171         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
172                 dump.u_dsize = 0;
173 
174         /* Make sure we have enough room to write the stack and data areas. */
175         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
176                 dump.u_ssize = 0;
177 
178         /* make sure we actually have a data and stack area to dump */
179         set_fs(USER_DS);
180         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
181                        dump.u_dsize << PAGE_SHIFT))
182                 dump.u_dsize = 0;
183         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
184                        dump.u_ssize << PAGE_SHIFT))
185                 dump.u_ssize = 0;
186 
187         set_fs(KERNEL_DS);
188         /* struct user */
189         if (!dump_emit(cprm, &dump, sizeof(dump)))
190                 goto end_coredump;
191         /* Now dump all of the user data.  Include malloced stuff as well */
192         if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
193                 goto end_coredump;
194         /* now we start writing out the user space info */
195         set_fs(USER_DS);
196         /* Dump the data area */
197         if (dump.u_dsize != 0) {
198                 dump_start = START_DATA(dump);
199                 dump_size = dump.u_dsize << PAGE_SHIFT;
200                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
201                         goto end_coredump;
202         }
203         /* Now prepare to dump the stack area */
204         if (dump.u_ssize != 0) {
205                 dump_start = START_STACK(dump);
206                 dump_size = dump.u_ssize << PAGE_SHIFT;
207                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
208                         goto end_coredump;
209         }
210 end_coredump:
211         set_fs(fs);
212         return has_dumped;
213 }
214 #endif
215 
216 /*
217  * create_aout_tables() parses the env- and arg-strings in new user
218  * memory and creates the pointer tables from them, and puts their
219  * addresses on the "stack", returning the new stack pointer value.
220  */
221 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
222 {
223         u32 __user *argv, *envp, *sp;
224         int argc = bprm->argc, envc = bprm->envc;
225 
226         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
227         sp -= envc+1;
228         envp = sp;
229         sp -= argc+1;
230         argv = sp;
231         put_user((unsigned long) envp, --sp);
232         put_user((unsigned long) argv, --sp);
233         put_user(argc, --sp);
234         current->mm->arg_start = (unsigned long) p;
235         while (argc-- > 0) {
236                 char c;
237 
238                 put_user((u32)(unsigned long)p, argv++);
239                 do {
240                         get_user(c, p++);
241                 } while (c);
242         }
243         put_user(0, argv);
244         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
245         while (envc-- > 0) {
246                 char c;
247 
248                 put_user((u32)(unsigned long)p, envp++);
249                 do {
250                         get_user(c, p++);
251                 } while (c);
252         }
253         put_user(0, envp);
254         current->mm->env_end = (unsigned long) p;
255         return sp;
256 }
257 
258 /*
259  * These are the functions used to load a.out style executables and shared
260  * libraries.  There is no binary dependent code anywhere else.
261  */
262 static int load_aout_binary(struct linux_binprm *bprm)
263 {
264         unsigned long error, fd_offset, rlim;
265         struct pt_regs *regs = current_pt_regs();
266         struct exec ex;
267         int retval;
268 
269         ex = *((struct exec *) bprm->buf);              /* exec-header */
270         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
271              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
272             N_TRSIZE(ex) || N_DRSIZE(ex) ||
273             i_size_read(file_inode(bprm->file)) <
274             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
275                 return -ENOEXEC;
276         }
277 
278         fd_offset = N_TXTOFF(ex);
279 
280         /* Check initial limits. This avoids letting people circumvent
281          * size limits imposed on them by creating programs with large
282          * arrays in the data or bss.
283          */
284         rlim = rlimit(RLIMIT_DATA);
285         if (rlim >= RLIM_INFINITY)
286                 rlim = ~0;
287         if (ex.a_data + ex.a_bss > rlim)
288                 return -ENOMEM;
289 
290         /* Flush all traces of the currently running executable */
291         retval = flush_old_exec(bprm);
292         if (retval)
293                 return retval;
294 
295         /* OK, This is the point of no return */
296         set_personality(PER_LINUX);
297         set_personality_ia32(false);
298 
299         setup_new_exec(bprm);
300 
301         regs->cs = __USER32_CS;
302         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
303                 regs->r13 = regs->r14 = regs->r15 = 0;
304 
305         current->mm->end_code = ex.a_text +
306                 (current->mm->start_code = N_TXTADDR(ex));
307         current->mm->end_data = ex.a_data +
308                 (current->mm->start_data = N_DATADDR(ex));
309         current->mm->brk = ex.a_bss +
310                 (current->mm->start_brk = N_BSSADDR(ex));
311 
312         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
313         if (retval < 0) {
314                 /* Someone check-me: is this error path enough? */
315                 send_sig(SIGKILL, current, 0);
316                 return retval;
317         }
318 
319         install_exec_creds(bprm);
320 
321         if (N_MAGIC(ex) == OMAGIC) {
322                 unsigned long text_addr, map_size;
323 
324                 text_addr = N_TXTADDR(ex);
325                 map_size = ex.a_text+ex.a_data;
326 
327                 error = vm_brk(text_addr & PAGE_MASK, map_size);
328 
329                 if (error != (text_addr & PAGE_MASK)) {
330                         send_sig(SIGKILL, current, 0);
331                         return error;
332                 }
333 
334                 error = read_code(bprm->file, text_addr, 32,
335                                   ex.a_text + ex.a_data);
336                 if ((signed long)error < 0) {
337                         send_sig(SIGKILL, current, 0);
338                         return error;
339                 }
340         } else {
341 #ifdef WARN_OLD
342                 static unsigned long error_time, error_time2;
343                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
344                     (N_MAGIC(ex) != NMAGIC) &&
345                                 time_after(jiffies, error_time2 + 5*HZ)) {
346                         printk(KERN_NOTICE "executable not page aligned\n");
347                         error_time2 = jiffies;
348                 }
349 
350                 if ((fd_offset & ~PAGE_MASK) != 0 &&
351                             time_after(jiffies, error_time + 5*HZ)) {
352                         printk(KERN_WARNING
353                                "fd_offset is not page aligned. Please convert "
354                                "program: %s\n",
355                                bprm->file->f_path.dentry->d_name.name);
356                         error_time = jiffies;
357                 }
358 #endif
359 
360                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
361                         vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
362                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
363                                         ex.a_text+ex.a_data);
364                         goto beyond_if;
365                 }
366 
367                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
368                                 PROT_READ | PROT_EXEC,
369                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
370                                 MAP_EXECUTABLE | MAP_32BIT,
371                                 fd_offset);
372 
373                 if (error != N_TXTADDR(ex)) {
374                         send_sig(SIGKILL, current, 0);
375                         return error;
376                 }
377 
378                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
379                                 PROT_READ | PROT_WRITE | PROT_EXEC,
380                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
381                                 MAP_EXECUTABLE | MAP_32BIT,
382                                 fd_offset + ex.a_text);
383                 if (error != N_DATADDR(ex)) {
384                         send_sig(SIGKILL, current, 0);
385                         return error;
386                 }
387         }
388 beyond_if:
389         set_binfmt(&aout_format);
390 
391         set_brk(current->mm->start_brk, current->mm->brk);
392 
393         current->mm->start_stack =
394                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
395         /* start thread */
396         loadsegment(fs, 0);
397         loadsegment(ds, __USER32_DS);
398         loadsegment(es, __USER32_DS);
399         load_gs_index(0);
400         (regs)->ip = ex.a_entry;
401         (regs)->sp = current->mm->start_stack;
402         (regs)->flags = 0x200;
403         (regs)->cs = __USER32_CS;
404         (regs)->ss = __USER32_DS;
405         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
406         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
407         set_fs(USER_DS);
408         return 0;
409 }
410 
411 static int load_aout_library(struct file *file)
412 {
413         unsigned long bss, start_addr, len, error;
414         int retval;
415         struct exec ex;
416 
417 
418         retval = -ENOEXEC;
419         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
420         if (error != sizeof(ex))
421                 goto out;
422 
423         /* We come in here for the regular a.out style of shared libraries */
424         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
425             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
426             i_size_read(file_inode(file)) <
427             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
428                 goto out;
429         }
430 
431         if (N_FLAGS(ex))
432                 goto out;
433 
434         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
435            this off to get the starting address for the page */
436 
437         start_addr =  ex.a_entry & 0xfffff000;
438 
439         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
440 #ifdef WARN_OLD
441                 static unsigned long error_time;
442                 if (time_after(jiffies, error_time + 5*HZ)) {
443                         printk(KERN_WARNING
444                                "N_TXTOFF is not page aligned. Please convert "
445                                "library: %s\n",
446                                file->f_path.dentry->d_name.name);
447                         error_time = jiffies;
448                 }
449 #endif
450                 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
451 
452                 read_code(file, start_addr, N_TXTOFF(ex),
453                           ex.a_text + ex.a_data);
454                 retval = 0;
455                 goto out;
456         }
457         /* Now use mmap to map the library into memory. */
458         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
459                         PROT_READ | PROT_WRITE | PROT_EXEC,
460                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
461                         N_TXTOFF(ex));
462         retval = error;
463         if (error != start_addr)
464                 goto out;
465 
466         len = PAGE_ALIGN(ex.a_text + ex.a_data);
467         bss = ex.a_text + ex.a_data + ex.a_bss;
468         if (bss > len) {
469                 error = vm_brk(start_addr + len, bss - len);
470                 retval = error;
471                 if (error != start_addr + len)
472                         goto out;
473         }
474         retval = 0;
475 out:
476         return retval;
477 }
478 
479 static int __init init_aout_binfmt(void)
480 {
481         register_binfmt(&aout_format);
482         return 0;
483 }
484 
485 static void __exit exit_aout_binfmt(void)
486 {
487         unregister_binfmt(&aout_format);
488 }
489 
490 module_init(init_aout_binfmt);
491 module_exit(exit_aout_binfmt);
492 MODULE_LICENSE("GPL");
493 

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