blob: 70789e198dea9249e1ad3388a25ba209769acb12 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Mike Frysingere6084d42014-12-10 15:52:10 -08002 * binfmt_misc.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Mike Frysingere6084d42014-12-10 15:52:10 -08004 * Copyright (C) 1997 Richard Günther
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Mike Frysingere6084d42014-12-10 15:52:10 -08006 * binfmt_misc detects binaries via a magic or filename extension and invokes
7 * a specified wrapper. See Documentation/binfmt_misc.txt for more details.
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 */
9
Mike Frysinger6b899c42014-12-10 15:52:08 -080010#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/module.h>
13#include <linux/init.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040014#include <linux/sched.h>
Muthu Kumarb502bd12012-03-23 15:01:50 -070015#include <linux/magic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/binfmts.h>
17#include <linux/slab.h>
18#include <linux/ctype.h>
Andy Shevchenko8d82e182013-04-30 15:27:33 -070019#include <linux/string_helpers.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/file.h>
21#include <linux/pagemap.h>
22#include <linux/namei.h>
23#include <linux/mount.h>
24#include <linux/syscalls.h>
Akinobu Mita6e2c10a2008-07-23 21:29:15 -070025#include <linux/fs.h>
Mike Frysinger6b899c42014-12-10 15:52:08 -080026#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Mike Frysinger6b899c42014-12-10 15:52:08 -080028#ifdef DEBUG
29# define USE_DEBUG 1
30#else
31# define USE_DEBUG 0
32#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34enum {
35 VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
36};
37
38static LIST_HEAD(entries);
39static int enabled = 1;
40
41enum {Enabled, Magic};
Mike Frysingere6084d42014-12-10 15:52:10 -080042#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
43#define MISC_FMT_OPEN_BINARY (1 << 30)
44#define MISC_FMT_CREDENTIALS (1 << 29)
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
46typedef struct {
47 struct list_head list;
48 unsigned long flags; /* type, status, etc. */
49 int offset; /* offset of magic */
50 int size; /* size of magic/mask */
51 char *magic; /* magic or filename extension */
52 char *mask; /* mask, NULL for exact match */
53 char *interpreter; /* filename of interpreter */
54 char *name;
55 struct dentry *dentry;
56} Node;
57
58static DEFINE_RWLOCK(entries_lock);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -040059static struct file_system_type bm_fs_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060static struct vfsmount *bm_mnt;
61static int entry_count;
62
Mike Frysingerbbaecc02014-10-13 15:52:03 -070063/*
64 * Max length of the register string. Determined by:
65 * - 7 delimiters
66 * - name: ~50 bytes
67 * - type: 1 byte
68 * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE)
69 * - magic: 128 bytes (512 in escaped form)
70 * - mask: 128 bytes (512 in escaped form)
71 * - interp: ~50 bytes
72 * - flags: 5 bytes
73 * Round that up a bit, and then back off to hold the internal data
74 * (like struct Node).
75 */
76#define MAX_REGISTER_LENGTH 1920
77
78/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 * Check if we support the binfmt
80 * if we do, return the node, else NULL
81 * locking is done in load_misc_binary
82 */
83static Node *check_file(struct linux_binprm *bprm)
84{
85 char *p = strrchr(bprm->interp, '.');
86 struct list_head *l;
87
Mike Frysinger6b899c42014-12-10 15:52:08 -080088 /* Walk all the registered handlers. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 list_for_each(l, &entries) {
90 Node *e = list_entry(l, Node, list);
91 char *s;
92 int j;
93
Mike Frysinger6b899c42014-12-10 15:52:08 -080094 /* Make sure this one is currently enabled. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 if (!test_bit(Enabled, &e->flags))
96 continue;
97
Mike Frysinger6b899c42014-12-10 15:52:08 -080098 /* Do matching based on extension if applicable. */
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 if (!test_bit(Magic, &e->flags)) {
100 if (p && !strcmp(e->magic, p + 1))
101 return e;
102 continue;
103 }
104
Mike Frysinger6b899c42014-12-10 15:52:08 -0800105 /* Do matching based on magic & mask. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 s = bprm->buf + e->offset;
107 if (e->mask) {
108 for (j = 0; j < e->size; j++)
109 if ((*s++ ^ e->magic[j]) & e->mask[j])
110 break;
111 } else {
112 for (j = 0; j < e->size; j++)
113 if ((*s++ ^ e->magic[j]))
114 break;
115 }
116 if (j == e->size)
117 return e;
118 }
119 return NULL;
120}
121
122/*
123 * the loader itself
124 */
Al Viro71613c32012-10-20 22:00:48 -0400125static int load_misc_binary(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126{
127 Node *fmt;
Mike Frysingere6084d42014-12-10 15:52:10 -0800128 struct file *interp_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 char iname[BINPRM_BUF_SIZE];
David Howellsd7627462010-08-17 23:52:56 +0100130 const char *iname_addr = iname;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 int retval;
132 int fd_binary = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
134 retval = -ENOEXEC;
135 if (!enabled)
Mike Frysingere6084d42014-12-10 15:52:10 -0800136 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138 /* to keep locking time low, we copy the interpreter string */
139 read_lock(&entries_lock);
140 fmt = check_file(bprm);
141 if (fmt)
142 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE);
143 read_unlock(&entries_lock);
144 if (!fmt)
Mike Frysingere6084d42014-12-10 15:52:10 -0800145 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
147 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700148 retval = remove_arg_zero(bprm);
149 if (retval)
Mike Frysingere6084d42014-12-10 15:52:10 -0800150 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 }
152
153 if (fmt->flags & MISC_FMT_OPEN_BINARY) {
154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 /* if the binary should be opened on behalf of the
156 * interpreter than keep it open and assign descriptor
Mike Frysingere6084d42014-12-10 15:52:10 -0800157 * to it
158 */
Yann Droneaudc6cb8982014-12-10 15:45:42 -0800159 fd_binary = get_unused_fd_flags(0);
Mike Frysingere6084d42014-12-10 15:52:10 -0800160 if (fd_binary < 0) {
161 retval = fd_binary;
162 goto ret;
163 }
164 fd_install(fd_binary, bprm->file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
166 /* if the binary is not readable than enforce mm->dumpable=0
167 regardless of the interpreter's permissions */
Al Viro1b5d7832011-06-19 12:49:47 -0400168 would_dump(bprm, bprm->file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
170 allow_write_access(bprm->file);
171 bprm->file = NULL;
172
173 /* mark the bprm that fd should be passed to interp */
174 bprm->interp_flags |= BINPRM_FLAGS_EXECFD;
175 bprm->interp_data = fd_binary;
176
Mike Frysingere6084d42014-12-10 15:52:10 -0800177 } else {
178 allow_write_access(bprm->file);
179 fput(bprm->file);
180 bprm->file = NULL;
181 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 /* make argv[1] be the path to the binary */
Mike Frysingere6084d42014-12-10 15:52:10 -0800183 retval = copy_strings_kernel(1, &bprm->interp, bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 if (retval < 0)
Mike Frysingere6084d42014-12-10 15:52:10 -0800185 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 bprm->argc++;
187
188 /* add the interp as argv[0] */
Mike Frysingere6084d42014-12-10 15:52:10 -0800189 retval = copy_strings_kernel(1, &iname_addr, bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 if (retval < 0)
Mike Frysingere6084d42014-12-10 15:52:10 -0800191 goto error;
192 bprm->argc++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
Kees Cookb66c5982012-12-20 15:05:16 -0800194 /* Update interp in case binfmt_script needs it. */
195 retval = bprm_change_interp(iname, bprm);
196 if (retval < 0)
Mike Frysingere6084d42014-12-10 15:52:10 -0800197 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
Mike Frysingere6084d42014-12-10 15:52:10 -0800199 interp_file = open_exec(iname);
200 retval = PTR_ERR(interp_file);
201 if (IS_ERR(interp_file))
202 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204 bprm->file = interp_file;
205 if (fmt->flags & MISC_FMT_CREDENTIALS) {
206 /*
207 * No need to call prepare_binprm(), it's already been
208 * done. bprm->buf is stale, update from interp_file.
209 */
210 memset(bprm->buf, 0, BINPRM_BUF_SIZE);
211 retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
212 } else
Mike Frysingere6084d42014-12-10 15:52:10 -0800213 retval = prepare_binprm(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
215 if (retval < 0)
Mike Frysingere6084d42014-12-10 15:52:10 -0800216 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
Al Viro3c456bf2012-10-20 21:53:31 -0400218 retval = search_binary_handler(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (retval < 0)
Mike Frysingere6084d42014-12-10 15:52:10 -0800220 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Mike Frysingere6084d42014-12-10 15:52:10 -0800222ret:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 return retval;
Mike Frysingere6084d42014-12-10 15:52:10 -0800224error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 if (fd_binary > 0)
226 sys_close(fd_binary);
227 bprm->interp_flags = 0;
228 bprm->interp_data = 0;
Mike Frysingere6084d42014-12-10 15:52:10 -0800229 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
232/* Command parsers */
233
234/*
235 * parses and copies one argument enclosed in del from *sp to *dp,
236 * recognising the \x special.
237 * returns pointer to the copied argument or NULL in case of an
238 * error (and sets err) or null argument length.
239 */
240static char *scanarg(char *s, char del)
241{
242 char c;
243
244 while ((c = *s++) != del) {
245 if (c == '\\' && *s == 'x') {
246 s++;
247 if (!isxdigit(*s++))
248 return NULL;
249 if (!isxdigit(*s++))
250 return NULL;
251 }
252 }
253 return s;
254}
255
Mike Frysingere6084d42014-12-10 15:52:10 -0800256static char *check_special_flags(char *sfs, Node *e)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257{
Mike Frysingere6084d42014-12-10 15:52:10 -0800258 char *p = sfs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 int cont = 1;
260
261 /* special flags */
262 while (cont) {
263 switch (*p) {
Mike Frysingere6084d42014-12-10 15:52:10 -0800264 case 'P':
265 pr_debug("register: flag: P (preserve argv0)\n");
266 p++;
267 e->flags |= MISC_FMT_PRESERVE_ARGV0;
268 break;
269 case 'O':
270 pr_debug("register: flag: O (open binary)\n");
271 p++;
272 e->flags |= MISC_FMT_OPEN_BINARY;
273 break;
274 case 'C':
275 pr_debug("register: flag: C (preserve creds)\n");
276 p++;
277 /* this flags also implies the
278 open-binary flag */
279 e->flags |= (MISC_FMT_CREDENTIALS |
280 MISC_FMT_OPEN_BINARY);
281 break;
282 default:
283 cont = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 }
285 }
286
287 return p;
288}
Mike Frysingere6084d42014-12-10 15:52:10 -0800289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/*
291 * This registers a new binary format, it recognises the syntax
292 * ':name:type:offset:magic:mask:interpreter:flags'
293 * where the ':' is the IFS, that can be chosen with the first char
294 */
295static Node *create_entry(const char __user *buffer, size_t count)
296{
297 Node *e;
298 int memsize, err;
299 char *buf, *p;
300 char del;
301
Mike Frysinger6b899c42014-12-10 15:52:08 -0800302 pr_debug("register: received %zu bytes\n", count);
303
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 /* some sanity checks */
305 err = -EINVAL;
Mike Frysingerbbaecc02014-10-13 15:52:03 -0700306 if ((count < 11) || (count > MAX_REGISTER_LENGTH))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 goto out;
308
309 err = -ENOMEM;
310 memsize = sizeof(Node) + count + 8;
Andrew Mortonf7e1ad12014-12-10 15:52:13 -0800311 e = kmalloc(memsize, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 if (!e)
313 goto out;
314
315 p = buf = (char *)e + sizeof(Node);
316
317 memset(e, 0, sizeof(Node));
318 if (copy_from_user(buf, buffer, count))
Mike Frysingere6084d42014-12-10 15:52:10 -0800319 goto efault;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320
321 del = *p++; /* delimeter */
322
Mike Frysinger6b899c42014-12-10 15:52:08 -0800323 pr_debug("register: delim: %#x {%c}\n", del, del);
324
325 /* Pad the buffer with the delim to simplify parsing below. */
Mike Frysingere6084d42014-12-10 15:52:10 -0800326 memset(buf + count, del, 8);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
Mike Frysinger6b899c42014-12-10 15:52:08 -0800328 /* Parse the 'name' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 e->name = p;
330 p = strchr(p, del);
331 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800332 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 *p++ = '\0';
334 if (!e->name[0] ||
335 !strcmp(e->name, ".") ||
336 !strcmp(e->name, "..") ||
337 strchr(e->name, '/'))
Mike Frysingere6084d42014-12-10 15:52:10 -0800338 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800339
340 pr_debug("register: name: {%s}\n", e->name);
341
342 /* Parse the 'type' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 switch (*p++) {
Mike Frysinger6b899c42014-12-10 15:52:08 -0800344 case 'E':
345 pr_debug("register: type: E (extension)\n");
346 e->flags = 1 << Enabled;
347 break;
348 case 'M':
349 pr_debug("register: type: M (magic)\n");
350 e->flags = (1 << Enabled) | (1 << Magic);
351 break;
352 default:
Mike Frysingere6084d42014-12-10 15:52:10 -0800353 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 }
355 if (*p++ != del)
Mike Frysingere6084d42014-12-10 15:52:10 -0800356 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800357
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 if (test_bit(Magic, &e->flags)) {
Mike Frysinger6b899c42014-12-10 15:52:08 -0800359 /* Handle the 'M' (magic) format. */
360 char *s;
361
362 /* Parse the 'offset' field. */
363 s = strchr(p, del);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 if (!s)
Mike Frysingere6084d42014-12-10 15:52:10 -0800365 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 *s++ = '\0';
367 e->offset = simple_strtoul(p, &p, 10);
368 if (*p++)
Mike Frysingere6084d42014-12-10 15:52:10 -0800369 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800370 pr_debug("register: offset: %#x\n", e->offset);
371
372 /* Parse the 'magic' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 e->magic = p;
374 p = scanarg(p, del);
375 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800376 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 p[-1] = '\0';
Mike Frysinger6b899c42014-12-10 15:52:08 -0800378 if (p == e->magic)
Mike Frysingere6084d42014-12-10 15:52:10 -0800379 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800380 if (USE_DEBUG)
381 print_hex_dump_bytes(
382 KBUILD_MODNAME ": register: magic[raw]: ",
383 DUMP_PREFIX_NONE, e->magic, p - e->magic);
384
385 /* Parse the 'mask' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 e->mask = p;
387 p = scanarg(p, del);
388 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800389 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 p[-1] = '\0';
Mike Frysinger6b899c42014-12-10 15:52:08 -0800391 if (p == e->mask) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 e->mask = NULL;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800393 pr_debug("register: mask[raw]: none\n");
394 } else if (USE_DEBUG)
395 print_hex_dump_bytes(
396 KBUILD_MODNAME ": register: mask[raw]: ",
397 DUMP_PREFIX_NONE, e->mask, p - e->mask);
398
399 /*
400 * Decode the magic & mask fields.
401 * Note: while we might have accepted embedded NUL bytes from
402 * above, the unescape helpers here will stop at the first one
403 * it encounters.
404 */
Andy Shevchenko8d82e182013-04-30 15:27:33 -0700405 e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX);
406 if (e->mask &&
407 string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size)
Mike Frysingere6084d42014-12-10 15:52:10 -0800408 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 if (e->size + e->offset > BINPRM_BUF_SIZE)
Mike Frysingere6084d42014-12-10 15:52:10 -0800410 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800411 pr_debug("register: magic/mask length: %i\n", e->size);
412 if (USE_DEBUG) {
413 print_hex_dump_bytes(
414 KBUILD_MODNAME ": register: magic[decoded]: ",
415 DUMP_PREFIX_NONE, e->magic, e->size);
416
417 if (e->mask) {
418 int i;
Andrew Mortonf7e1ad12014-12-10 15:52:13 -0800419 char *masked = kmalloc(e->size, GFP_KERNEL);
Mike Frysinger6b899c42014-12-10 15:52:08 -0800420
421 print_hex_dump_bytes(
422 KBUILD_MODNAME ": register: mask[decoded]: ",
423 DUMP_PREFIX_NONE, e->mask, e->size);
424
425 if (masked) {
426 for (i = 0; i < e->size; ++i)
427 masked[i] = e->magic[i] & e->mask[i];
428 print_hex_dump_bytes(
429 KBUILD_MODNAME ": register: magic[masked]: ",
430 DUMP_PREFIX_NONE, masked, e->size);
431
432 kfree(masked);
433 }
434 }
435 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 } else {
Mike Frysinger6b899c42014-12-10 15:52:08 -0800437 /* Handle the 'E' (extension) format. */
438
439 /* Skip the 'offset' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 p = strchr(p, del);
441 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800442 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 *p++ = '\0';
Mike Frysinger6b899c42014-12-10 15:52:08 -0800444
445 /* Parse the 'magic' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 e->magic = p;
447 p = strchr(p, del);
448 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800449 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 *p++ = '\0';
451 if (!e->magic[0] || strchr(e->magic, '/'))
Mike Frysingere6084d42014-12-10 15:52:10 -0800452 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800453 pr_debug("register: extension: {%s}\n", e->magic);
454
455 /* Skip the 'mask' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 p = strchr(p, del);
457 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800458 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 *p++ = '\0';
460 }
Mike Frysinger6b899c42014-12-10 15:52:08 -0800461
462 /* Parse the 'interpreter' field. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 e->interpreter = p;
464 p = strchr(p, del);
465 if (!p)
Mike Frysingere6084d42014-12-10 15:52:10 -0800466 goto einval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 *p++ = '\0';
468 if (!e->interpreter[0])
Mike Frysingere6084d42014-12-10 15:52:10 -0800469 goto einval;
Mike Frysinger6b899c42014-12-10 15:52:08 -0800470 pr_debug("register: interpreter: {%s}\n", e->interpreter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
Mike Frysinger6b899c42014-12-10 15:52:08 -0800472 /* Parse the 'flags' field. */
Mike Frysingere6084d42014-12-10 15:52:10 -0800473 p = check_special_flags(p, e);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 if (*p == '\n')
475 p++;
476 if (p != buf + count)
Mike Frysingere6084d42014-12-10 15:52:10 -0800477 goto einval;
478
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 return e;
480
481out:
482 return ERR_PTR(err);
483
Mike Frysingere6084d42014-12-10 15:52:10 -0800484efault:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 kfree(e);
486 return ERR_PTR(-EFAULT);
Mike Frysingere6084d42014-12-10 15:52:10 -0800487einval:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 kfree(e);
489 return ERR_PTR(-EINVAL);
490}
491
492/*
493 * Set status of entry/binfmt_misc:
494 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc
495 */
496static int parse_command(const char __user *buffer, size_t count)
497{
498 char s[4];
499
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 if (count > 3)
501 return -EINVAL;
502 if (copy_from_user(s, buffer, count))
503 return -EFAULT;
Arnd Bergmannde8288b2014-10-13 15:52:08 -0700504 if (!count)
505 return 0;
Mike Frysingere6084d42014-12-10 15:52:10 -0800506 if (s[count - 1] == '\n')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 count--;
508 if (count == 1 && s[0] == '0')
509 return 1;
510 if (count == 1 && s[0] == '1')
511 return 2;
512 if (count == 2 && s[0] == '-' && s[1] == '1')
513 return 3;
514 return -EINVAL;
515}
516
517/* generic stuff */
518
519static void entry_status(Node *e, char *page)
520{
521 char *dp;
522 char *status = "disabled";
Mike Frysingere6084d42014-12-10 15:52:10 -0800523 const char *flags = "flags: ";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
525 if (test_bit(Enabled, &e->flags))
526 status = "enabled";
527
528 if (!VERBOSE_STATUS) {
529 sprintf(page, "%s\n", status);
530 return;
531 }
532
533 sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter);
534 dp = page + strlen(page);
535
536 /* print the special flags */
Mike Frysingere6084d42014-12-10 15:52:10 -0800537 sprintf(dp, "%s", flags);
538 dp += strlen(flags);
539 if (e->flags & MISC_FMT_PRESERVE_ARGV0)
540 *dp++ = 'P';
541 if (e->flags & MISC_FMT_OPEN_BINARY)
542 *dp++ = 'O';
543 if (e->flags & MISC_FMT_CREDENTIALS)
544 *dp++ = 'C';
545 *dp++ = '\n';
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546
547 if (!test_bit(Magic, &e->flags)) {
548 sprintf(dp, "extension .%s\n", e->magic);
549 } else {
550 int i;
551
552 sprintf(dp, "offset %i\nmagic ", e->offset);
553 dp = page + strlen(page);
554 for (i = 0; i < e->size; i++) {
555 sprintf(dp, "%02x", 0xff & (int) (e->magic[i]));
556 dp += 2;
557 }
558 if (e->mask) {
559 sprintf(dp, "\nmask ");
560 dp += 6;
561 for (i = 0; i < e->size; i++) {
562 sprintf(dp, "%02x", 0xff & (int) (e->mask[i]));
563 dp += 2;
564 }
565 }
566 *dp++ = '\n';
567 *dp = '\0';
568 }
569}
570
571static struct inode *bm_get_inode(struct super_block *sb, int mode)
572{
Mike Frysingere6084d42014-12-10 15:52:10 -0800573 struct inode *inode = new_inode(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -0400576 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 inode->i_atime = inode->i_mtime = inode->i_ctime =
579 current_fs_time(inode->i_sb);
580 }
581 return inode;
582}
583
Al Virob57922d2010-06-07 14:34:48 -0400584static void bm_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
Jan Karadbd57682012-05-03 14:48:02 +0200586 clear_inode(inode);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700587 kfree(inode->i_private);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588}
589
590static void kill_node(Node *e)
591{
592 struct dentry *dentry;
593
594 write_lock(&entries_lock);
595 dentry = e->dentry;
596 if (dentry) {
597 list_del_init(&e->list);
598 e->dentry = NULL;
599 }
600 write_unlock(&entries_lock);
601
602 if (dentry) {
Miklos Szeredi6d6b77f2011-10-28 14:13:28 +0200603 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 d_drop(dentry);
605 dput(dentry);
606 simple_release_fs(&bm_mnt, &entry_count);
607 }
608}
609
610/* /<entry> */
611
612static ssize_t
Mike Frysingere6084d42014-12-10 15:52:10 -0800613bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614{
Al Viro496ad9a2013-01-23 17:07:38 -0500615 Node *e = file_inode(file)->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 ssize_t res;
617 char *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Mike Frysingere6084d42014-12-10 15:52:10 -0800619 page = (char *) __get_free_page(GFP_KERNEL);
620 if (!page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 return -ENOMEM;
622
623 entry_status(e, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Akinobu Mita6e2c10a2008-07-23 21:29:15 -0700625 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
626
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 free_page((unsigned long) page);
628 return res;
629}
630
631static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
632 size_t count, loff_t *ppos)
633{
634 struct dentry *root;
Al Viro496ad9a2013-01-23 17:07:38 -0500635 Node *e = file_inode(file)->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 int res = parse_command(buffer, count);
637
638 switch (res) {
Mike Frysingere6084d42014-12-10 15:52:10 -0800639 case 1:
640 /* Disable this handler. */
641 clear_bit(Enabled, &e->flags);
642 break;
643 case 2:
644 /* Enable this handler. */
645 set_bit(Enabled, &e->flags);
646 break;
647 case 3:
648 /* Delete this handler. */
649 root = dget(file->f_path.dentry->d_sb->s_root);
650 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651
Mike Frysingere6084d42014-12-10 15:52:10 -0800652 kill_node(e);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
Mike Frysingere6084d42014-12-10 15:52:10 -0800654 mutex_unlock(&root->d_inode->i_mutex);
655 dput(root);
656 break;
657 default:
658 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 }
Mike Frysingere6084d42014-12-10 15:52:10 -0800660
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 return count;
662}
663
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800664static const struct file_operations bm_entry_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 .read = bm_entry_read,
666 .write = bm_entry_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200667 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668};
669
670/* /register */
671
672static ssize_t bm_register_write(struct file *file, const char __user *buffer,
673 size_t count, loff_t *ppos)
674{
675 Node *e;
676 struct inode *inode;
677 struct dentry *root, *dentry;
Al Virod8c95842011-12-07 18:16:57 -0500678 struct super_block *sb = file->f_path.dentry->d_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 int err = 0;
680
681 e = create_entry(buffer, count);
682
683 if (IS_ERR(e))
684 return PTR_ERR(e);
685
686 root = dget(sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800687 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 dentry = lookup_one_len(e->name, root, strlen(e->name));
689 err = PTR_ERR(dentry);
690 if (IS_ERR(dentry))
691 goto out;
692
693 err = -EEXIST;
694 if (dentry->d_inode)
695 goto out2;
696
697 inode = bm_get_inode(sb, S_IFREG | 0644);
698
699 err = -ENOMEM;
700 if (!inode)
701 goto out2;
702
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400703 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 if (err) {
705 iput(inode);
706 inode = NULL;
707 goto out2;
708 }
709
710 e->dentry = dget(dentry);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700711 inode->i_private = e;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 inode->i_fop = &bm_entry_operations;
713
714 d_instantiate(dentry, inode);
715 write_lock(&entries_lock);
716 list_add(&e->list, &entries);
717 write_unlock(&entries_lock);
718
719 err = 0;
720out2:
721 dput(dentry);
722out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800723 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 dput(root);
725
726 if (err) {
727 kfree(e);
728 return -EINVAL;
729 }
730 return count;
731}
732
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800733static const struct file_operations bm_register_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 .write = bm_register_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200735 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736};
737
738/* /status */
739
740static ssize_t
741bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
742{
Qinghuang Feng87113e802009-01-06 14:41:38 -0800743 char *s = enabled ? "enabled\n" : "disabled\n";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744
Akinobu Mita92f4c702007-05-09 02:33:32 -0700745 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746}
747
Mike Frysingere6084d42014-12-10 15:52:10 -0800748static ssize_t bm_status_write(struct file *file, const char __user *buffer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 size_t count, loff_t *ppos)
750{
751 int res = parse_command(buffer, count);
752 struct dentry *root;
753
754 switch (res) {
Mike Frysingere6084d42014-12-10 15:52:10 -0800755 case 1:
756 /* Disable all handlers. */
757 enabled = 0;
758 break;
759 case 2:
760 /* Enable all handlers. */
761 enabled = 1;
762 break;
763 case 3:
764 /* Delete all handlers. */
765 root = dget(file->f_path.dentry->d_sb->s_root);
766 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
Mike Frysingere6084d42014-12-10 15:52:10 -0800768 while (!list_empty(&entries))
769 kill_node(list_entry(entries.next, Node, list));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
Mike Frysingere6084d42014-12-10 15:52:10 -0800771 mutex_unlock(&root->d_inode->i_mutex);
772 dput(root);
773 break;
774 default:
775 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 }
Mike Frysingere6084d42014-12-10 15:52:10 -0800777
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 return count;
779}
780
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800781static const struct file_operations bm_status_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 .read = bm_status_read,
783 .write = bm_status_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200784 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785};
786
787/* Superblock handling */
788
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800789static const struct super_operations s_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 .statfs = simple_statfs,
Al Virob57922d2010-06-07 14:34:48 -0400791 .evict_inode = bm_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792};
793
Mike Frysingere6084d42014-12-10 15:52:10 -0800794static int bm_fill_super(struct super_block *sb, void *data, int silent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795{
Mike Frysingere6084d42014-12-10 15:52:10 -0800796 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 static struct tree_descr bm_files[] = {
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700798 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
799 [3] = {"register", &bm_register_operations, S_IWUSR},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 /* last one */ {""}
801 };
Mike Frysingere6084d42014-12-10 15:52:10 -0800802
803 err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 if (!err)
805 sb->s_op = &s_ops;
806 return err;
807}
808
Al Virofc14f2f2010-07-25 01:48:30 +0400809static struct dentry *bm_mount(struct file_system_type *fs_type,
810 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811{
Al Virofc14f2f2010-07-25 01:48:30 +0400812 return mount_single(fs_type, flags, data, bm_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813}
814
815static struct linux_binfmt misc_format = {
816 .module = THIS_MODULE,
817 .load_binary = load_misc_binary,
818};
819
820static struct file_system_type bm_fs_type = {
821 .owner = THIS_MODULE,
822 .name = "binfmt_misc",
Al Virofc14f2f2010-07-25 01:48:30 +0400823 .mount = bm_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 .kill_sb = kill_litter_super,
825};
Eric W. Biederman7f78e032013-03-02 19:39:14 -0800826MODULE_ALIAS_FS("binfmt_misc");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827
828static int __init init_misc_binfmt(void)
829{
830 int err = register_filesystem(&bm_fs_type);
Al Viro8fc3dc52012-03-17 03:05:16 -0400831 if (!err)
832 insert_binfmt(&misc_format);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 return err;
834}
835
836static void __exit exit_misc_binfmt(void)
837{
838 unregister_binfmt(&misc_format);
839 unregister_filesystem(&bm_fs_type);
840}
841
842core_initcall(init_misc_binfmt);
843module_exit(exit_misc_binfmt);
844MODULE_LICENSE("GPL");