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
38static int load_aout_binary(struct linux_binprm *);
39static int load_aout_library(struct file *);
40
41#ifdef CONFIG_COREDUMP
42static int aout_core_dump(struct coredump_params *);
43
44static 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 */
53static void dump_thread32(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
109static 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
119static 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
149static 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	strncpy(dump.u_comm, current->comm, sizeof(current->comm));
160	dump.u_ar0 = offsetof(struct user32, regs);
161	dump.signal = cprm->siginfo->si_signo;
162	dump_thread32(cprm->regs, &dump);
163
164	/*
165	 * If the size of the dump file exceeds the rlimit, then see
166	 * what would happen if we wrote the stack, but not the data
167	 * area.
168	 */
169	if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
170		dump.u_dsize = 0;
171
172	/* Make sure we have enough room to write the stack and data areas. */
173	if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
174		dump.u_ssize = 0;
175
176	/* make sure we actually have a data and stack area to dump */
177	set_fs(USER_DS);
178	if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
179		       dump.u_dsize << PAGE_SHIFT))
180		dump.u_dsize = 0;
181	if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
182		       dump.u_ssize << PAGE_SHIFT))
183		dump.u_ssize = 0;
184
185	set_fs(KERNEL_DS);
186	/* struct user */
187	if (!dump_emit(cprm, &dump, sizeof(dump)))
188		goto end_coredump;
189	/* Now dump all of the user data.  Include malloced stuff as well */
190	if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
191		goto end_coredump;
192	/* now we start writing out the user space info */
193	set_fs(USER_DS);
194	/* Dump the data area */
195	if (dump.u_dsize != 0) {
196		dump_start = START_DATA(dump);
197		dump_size = dump.u_dsize << PAGE_SHIFT;
198		if (!dump_emit(cprm, (void *)dump_start, dump_size))
199			goto end_coredump;
200	}
201	/* Now prepare to dump the stack area */
202	if (dump.u_ssize != 0) {
203		dump_start = START_STACK(dump);
204		dump_size = dump.u_ssize << PAGE_SHIFT;
205		if (!dump_emit(cprm, (void *)dump_start, dump_size))
206			goto end_coredump;
207	}
208end_coredump:
209	set_fs(fs);
210	return has_dumped;
211}
212#endif
213
214/*
215 * create_aout_tables() parses the env- and arg-strings in new user
216 * memory and creates the pointer tables from them, and puts their
217 * addresses on the "stack", returning the new stack pointer value.
218 */
219static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
220{
221	u32 __user *argv, *envp, *sp;
222	int argc = bprm->argc, envc = bprm->envc;
223
224	sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
225	sp -= envc+1;
226	envp = sp;
227	sp -= argc+1;
228	argv = sp;
229	put_user((unsigned long) envp, --sp);
230	put_user((unsigned long) argv, --sp);
231	put_user(argc, --sp);
232	current->mm->arg_start = (unsigned long) p;
233	while (argc-- > 0) {
234		char c;
235
236		put_user((u32)(unsigned long)p, argv++);
237		do {
238			get_user(c, p++);
239		} while (c);
240	}
241	put_user(0, argv);
242	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
243	while (envc-- > 0) {
244		char c;
245
246		put_user((u32)(unsigned long)p, envp++);
247		do {
248			get_user(c, p++);
249		} while (c);
250	}
251	put_user(0, envp);
252	current->mm->env_end = (unsigned long) p;
253	return sp;
254}
255
256/*
257 * These are the functions used to load a.out style executables and shared
258 * libraries.  There is no binary dependent code anywhere else.
259 */
260static int load_aout_binary(struct linux_binprm *bprm)
261{
262	unsigned long error, fd_offset, rlim;
263	struct pt_regs *regs = current_pt_regs();
264	struct exec ex;
265	int retval;
266
267	ex = *((struct exec *) bprm->buf);		/* exec-header */
268	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
269	     N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
270	    N_TRSIZE(ex) || N_DRSIZE(ex) ||
271	    i_size_read(file_inode(bprm->file)) <
272	    ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
273		return -ENOEXEC;
274	}
275
276	fd_offset = N_TXTOFF(ex);
277
278	/* Check initial limits. This avoids letting people circumvent
279	 * size limits imposed on them by creating programs with large
280	 * arrays in the data or bss.
281	 */
282	rlim = rlimit(RLIMIT_DATA);
283	if (rlim >= RLIM_INFINITY)
284		rlim = ~0;
285	if (ex.a_data + ex.a_bss > rlim)
286		return -ENOMEM;
287
288	/* Flush all traces of the currently running executable */
289	retval = flush_old_exec(bprm);
290	if (retval)
291		return retval;
292
293	/* OK, This is the point of no return */
294	set_personality(PER_LINUX);
295	set_personality_ia32(false);
296
297	setup_new_exec(bprm);
298
299	regs->cs = __USER32_CS;
300	regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
301		regs->r13 = regs->r14 = regs->r15 = 0;
302
303	current->mm->end_code = ex.a_text +
304		(current->mm->start_code = N_TXTADDR(ex));
305	current->mm->end_data = ex.a_data +
306		(current->mm->start_data = N_DATADDR(ex));
307	current->mm->brk = ex.a_bss +
308		(current->mm->start_brk = N_BSSADDR(ex));
309
310	retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
311	if (retval < 0)
312		return retval;
313
314	install_exec_creds(bprm);
315
316	if (N_MAGIC(ex) == OMAGIC) {
317		unsigned long text_addr, map_size;
318
319		text_addr = N_TXTADDR(ex);
320		map_size = ex.a_text+ex.a_data;
321
322		error = vm_brk(text_addr & PAGE_MASK, map_size);
323
324		if (error != (text_addr & PAGE_MASK))
325			return error;
326
327		error = read_code(bprm->file, text_addr, 32,
328				  ex.a_text + ex.a_data);
329		if ((signed long)error < 0)
330			return error;
331	} else {
332#ifdef WARN_OLD
333		static unsigned long error_time, error_time2;
334		if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
335		    (N_MAGIC(ex) != NMAGIC) &&
336				time_after(jiffies, error_time2 + 5*HZ)) {
337			printk(KERN_NOTICE "executable not page aligned\n");
338			error_time2 = jiffies;
339		}
340
341		if ((fd_offset & ~PAGE_MASK) != 0 &&
342			    time_after(jiffies, error_time + 5*HZ)) {
343			printk(KERN_WARNING
344			       "fd_offset is not page aligned. Please convert "
345			       "program: %pD\n",
346			       bprm->file);
347			error_time = jiffies;
348		}
349#endif
350
351		if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
352			vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
353			read_code(bprm->file, N_TXTADDR(ex), fd_offset,
354					ex.a_text+ex.a_data);
355			goto beyond_if;
356		}
357
358		error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
359				PROT_READ | PROT_EXEC,
360				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
361				MAP_EXECUTABLE | MAP_32BIT,
362				fd_offset);
363
364		if (error != N_TXTADDR(ex))
365			return error;
366
367		error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
368				PROT_READ | PROT_WRITE | PROT_EXEC,
369				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
370				MAP_EXECUTABLE | MAP_32BIT,
371				fd_offset + ex.a_text);
372		if (error != N_DATADDR(ex))
373			return error;
374	}
375beyond_if:
376	set_binfmt(&aout_format);
377
378	set_brk(current->mm->start_brk, current->mm->brk);
379
380	current->mm->start_stack =
381		(unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
382	/* start thread */
383	loadsegment(fs, 0);
384	loadsegment(ds, __USER32_DS);
385	loadsegment(es, __USER32_DS);
386	load_gs_index(0);
387	(regs)->ip = ex.a_entry;
388	(regs)->sp = current->mm->start_stack;
389	(regs)->flags = 0x200;
390	(regs)->cs = __USER32_CS;
391	(regs)->ss = __USER32_DS;
392	regs->r8 = regs->r9 = regs->r10 = regs->r11 =
393	regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
394	set_fs(USER_DS);
395	return 0;
396}
397
398static int load_aout_library(struct file *file)
399{
400	unsigned long bss, start_addr, len, error;
401	int retval;
402	struct exec ex;
403
404
405	retval = -ENOEXEC;
406	error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
407	if (error != sizeof(ex))
408		goto out;
409
410	/* We come in here for the regular a.out style of shared libraries */
411	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
412	    N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
413	    i_size_read(file_inode(file)) <
414	    ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
415		goto out;
416	}
417
418	if (N_FLAGS(ex))
419		goto out;
420
421	/* For  QMAGIC, the starting address is 0x20 into the page.  We mask
422	   this off to get the starting address for the page */
423
424	start_addr =  ex.a_entry & 0xfffff000;
425
426	if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
427#ifdef WARN_OLD
428		static unsigned long error_time;
429		if (time_after(jiffies, error_time + 5*HZ)) {
430			printk(KERN_WARNING
431			       "N_TXTOFF is not page aligned. Please convert "
432			       "library: %pD\n",
433			       file);
434			error_time = jiffies;
435		}
436#endif
437		vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
438
439		read_code(file, start_addr, N_TXTOFF(ex),
440			  ex.a_text + ex.a_data);
441		retval = 0;
442		goto out;
443	}
444	/* Now use mmap to map the library into memory. */
445	error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
446			PROT_READ | PROT_WRITE | PROT_EXEC,
447			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
448			N_TXTOFF(ex));
449	retval = error;
450	if (error != start_addr)
451		goto out;
452
453	len = PAGE_ALIGN(ex.a_text + ex.a_data);
454	bss = ex.a_text + ex.a_data + ex.a_bss;
455	if (bss > len) {
456		error = vm_brk(start_addr + len, bss - len);
457		retval = error;
458		if (error != start_addr + len)
459			goto out;
460	}
461	retval = 0;
462out:
463	return retval;
464}
465
466static int __init init_aout_binfmt(void)
467{
468	register_binfmt(&aout_format);
469	return 0;
470}
471
472static void __exit exit_aout_binfmt(void)
473{
474	unregister_binfmt(&aout_format);
475}
476
477module_init(init_aout_binfmt);
478module_exit(exit_aout_binfmt);
479MODULE_LICENSE("GPL");
480