]>
Commit | Line | Data |
---|---|---|
db3476af FW |
1 | /* libio vtable validation. |
2 | Copyright (C) 2016 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <dlfcn.h> | |
20 | #include <libioP.h> | |
21 | #include <stdio.h> | |
22 | ||
23 | #ifdef SHARED | |
24 | ||
25 | void (*IO_accept_foreign_vtables) (void) attribute_hidden; | |
26 | ||
27 | /* Used to detected multiple libcs. */ | |
28 | extern struct dl_open_hook *_dl_open_hook; | |
29 | libc_hidden_proto (_dl_open_hook); | |
30 | ||
31 | #else /* !SHARED */ | |
32 | ||
33 | /* Used to check whether static dlopen support is needed. */ | |
34 | # pragma weak __dlopen | |
35 | ||
36 | #endif | |
37 | ||
38 | void attribute_hidden | |
39 | _IO_vtable_check (void) | |
40 | { | |
41 | #ifdef SHARED | |
42 | /* Honor the compatibility flag. */ | |
43 | void (*flag) (void) = atomic_load_relaxed (&IO_accept_foreign_vtables); | |
44 | PTR_DEMANGLE (flag); | |
45 | if (flag == &_IO_vtable_check) | |
46 | return; | |
47 | ||
48 | /* In case this libc copy is in a non-default namespace, we always | |
49 | need to accept foreign vtables because there is always a | |
50 | possibility that FILE * objects are passed across the linking | |
51 | boundary. */ | |
52 | { | |
53 | Dl_info di; | |
54 | struct link_map *l; | |
55 | if (_dl_open_hook != NULL | |
56 | || (_dl_addr (_IO_vtable_check, &di, &l, NULL) != 0 | |
57 | && l->l_ns != LM_ID_BASE)) | |
58 | return; | |
59 | } | |
60 | ||
61 | #else /* !SHARED */ | |
62 | /* We cannot perform vtable validation in the static dlopen case | |
63 | because FILE * handles might be passed back and forth across the | |
64 | boundary. Therefore, we disable checking in this case. */ | |
65 | if (__dlopen != NULL) | |
66 | return; | |
67 | #endif | |
68 | ||
69 | __libc_fatal ("Fatal error: glibc detected an invalid stdio handle\n"); | |
70 | } |