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1718c60c | 1 | /* Operating system specific code for generic dynamic loader functions. Linux. |
688903eb | 2 | Copyright (C) 2000-2018 Free Software Foundation, Inc. |
32b4fe6a UD |
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 | |
41bdb6e2 AJ |
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. | |
32b4fe6a UD |
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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
32b4fe6a | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
32b4fe6a | 18 | |
1718c60c | 19 | #include <dl-sysdep.h> |
15a856b1 | 20 | #include <endian.h> |
39546e34 | 21 | #include <fcntl.h> |
35f1e827 | 22 | #include <stdint.h> |
05f399e6 | 23 | #include <not-cancel.h> |
b4246fd6 UD |
24 | |
25 | #ifndef MIN | |
26 | # define MIN(a,b) (((a)<(b))?(a):(b)) | |
27 | #endif | |
32b4fe6a | 28 | |
1718c60c | 29 | #define DL_SYSDEP_OSCHECK(FATAL) \ |
32b4fe6a | 30 | do { \ |
1718c60c RM |
31 | /* Test whether the kernel is new enough. This test is only performed \ |
32 | if the library is not compiled to run on all kernels. */ \ | |
a334319f | 33 | \ |
1718c60c | 34 | int version = _dl_discover_osversion (); \ |
a1ffb40e | 35 | if (__glibc_likely (version >= 0)) \ |
1718c60c | 36 | { \ |
609b254a UD |
37 | if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \ |
38 | || GLRO(dl_osversion) > version) \ | |
39 | GLRO(dl_osversion) = version; \ | |
32b4fe6a UD |
40 | \ |
41 | /* Now we can test with the required version. */ \ | |
1718c60c | 42 | if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \ |
32b4fe6a UD |
43 | /* Not sufficent. */ \ |
44 | FATAL ("FATAL: kernel too old\n"); \ | |
45 | } \ | |
1718c60c RM |
46 | else if (__LINUX_KERNEL_VERSION > 0) \ |
47 | FATAL ("FATAL: cannot determine kernel version\n"); \ | |
32b4fe6a | 48 | } while (0) |
35f1e827 UD |
49 | |
50 | static inline uintptr_t __attribute__ ((always_inline)) | |
965cb60a | 51 | _dl_setup_stack_chk_guard (void *dl_random) |
35f1e827 | 52 | { |
15a856b1 UD |
53 | union |
54 | { | |
55 | uintptr_t num; | |
56 | unsigned char bytes[sizeof (uintptr_t)]; | |
57 | } ret; | |
58 | ||
4a103975 JM |
59 | /* We need in the moment only 8 bytes on 32-bit platforms and 16 |
60 | bytes on 64-bit platforms. Therefore we can use the data | |
61 | directly and not use the kernel-provided data to seed a PRNG. */ | |
62 | memcpy (ret.bytes, dl_random, sizeof (ret)); | |
15a856b1 | 63 | #if BYTE_ORDER == LITTLE_ENDIAN |
4a103975 | 64 | ret.num &= ~(uintptr_t) 0xff; |
15a856b1 | 65 | #elif BYTE_ORDER == BIG_ENDIAN |
4a103975 | 66 | ret.num &= ~((uintptr_t) 0xff << (8 * (sizeof (ret) - 1))); |
15a856b1 UD |
67 | #else |
68 | # error "BYTE_ORDER unknown" | |
69 | #endif | |
15a856b1 | 70 | return ret.num; |
965cb60a UD |
71 | } |
72 | ||
73 | static inline uintptr_t __attribute__ ((always_inline)) | |
74 | _dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard) | |
75 | { | |
76 | uintptr_t ret; | |
4a103975 | 77 | memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret)); |
35f1e827 UD |
78 | return ret; |
79 | } |