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774f5a30 | 1 | /* Check for executable stacks in DSOs. |
30950a5f | 2 | Copyright (C) 2009, 2010 Free Software Foundation, Inc. |
774f5a30 UD |
3 | This file is part of the GNU C Library. |
4 | Contribute by Ulrich Drepper <drepper@redhat.com>. 2009. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
774f5a30 UD |
19 | |
20 | #include <byteswap.h> | |
21 | #include <elf.h> | |
22 | #include <endian.h> | |
23 | #include <fcntl.h> | |
24 | #include <stdio.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <unistd.h> | |
68dc9497 | 28 | #include "check-execstack.h" |
774f5a30 UD |
29 | |
30 | ||
31 | #ifdef BITS | |
32 | ||
33 | # define AB(name) _AB (name, BITS) | |
34 | # define _AB(name, bits) __AB (name, bits) | |
35 | # define __AB(name, bits) name##bits | |
36 | # define E(name) _E (name, BITS) | |
37 | # define _E(name, bits) __E (name, bits) | |
38 | # define __E(name, bits) Elf##bits##_##name | |
39 | # define SWAP(val) \ | |
40 | ({ __typeof (val) __res; \ | |
41 | if (((ehdr.e_ident[EI_DATA] == ELFDATA2MSB \ | |
42 | && BYTE_ORDER == LITTLE_ENDIAN) \ | |
43 | || (ehdr.e_ident[EI_DATA] == ELFDATA2LSB \ | |
44 | && BYTE_ORDER == BIG_ENDIAN)) \ | |
45 | && sizeof (val) != 1) \ | |
46 | { \ | |
47 | if (sizeof (val) == 2) \ | |
48 | __res = bswap_16 (val); \ | |
49 | else if (sizeof (val) == 4) \ | |
50 | __res = bswap_32 (val); \ | |
51 | else \ | |
52 | __res = bswap_64 (val); \ | |
53 | } \ | |
54 | else \ | |
55 | __res = (val); \ | |
56 | __res; }) | |
57 | ||
58 | ||
59 | static int | |
60 | AB(handle_file) (const char *fname, int fd) | |
61 | { | |
62 | E(Ehdr) ehdr; | |
63 | ||
64 | if (pread (fd, &ehdr, sizeof (ehdr), 0) != sizeof (ehdr)) | |
65 | { | |
66 | read_error: | |
67 | printf ("%s: read error: %m\n", fname); | |
68 | return 1; | |
69 | } | |
70 | ||
71 | const size_t phnum = SWAP (ehdr.e_phnum); | |
72 | const size_t phentsize = SWAP (ehdr.e_phentsize); | |
73 | ||
74 | /* Read the program header. */ | |
75 | E(Phdr) *phdr = alloca (phentsize * phnum); | |
76 | if (pread (fd, phdr, phentsize * phnum, SWAP (ehdr.e_phoff)) | |
77 | != phentsize * phnum) | |
78 | goto read_error; | |
79 | ||
80 | /* Search for the PT_GNU_STACK entry. */ | |
81 | for (size_t cnt = 0; cnt < phnum; ++cnt) | |
82 | if (SWAP (phdr[cnt].p_type) == PT_GNU_STACK) | |
83 | { | |
84 | unsigned int flags = SWAP(phdr[cnt].p_flags); | |
85 | if (flags & PF_X) | |
86 | { | |
87 | printf ("%s: executable stack signaled\n", fname); | |
88 | return 1; | |
89 | } | |
90 | ||
91 | return 0; | |
92 | } | |
93 | ||
68dc9497 AS |
94 | if (DEFAULT_STACK_PERMS & PF_X) |
95 | { | |
96 | printf ("%s: no PT_GNU_STACK entry\n", fname); | |
97 | return 1; | |
98 | } | |
99 | ||
100 | return 0; | |
774f5a30 UD |
101 | } |
102 | ||
103 | # undef BITS | |
104 | #else | |
105 | ||
106 | # define BITS 32 | |
107 | # include "check-execstack.c" | |
108 | ||
109 | # define BITS 64 | |
110 | # include "check-execstack.c" | |
111 | ||
112 | ||
113 | static int | |
114 | handle_file (const char *fname) | |
115 | { | |
116 | int fd = open (fname, O_RDONLY); | |
117 | if (fd == -1) | |
118 | { | |
119 | printf ("cannot open %s: %m\n", fname); | |
120 | return 1; | |
121 | } | |
122 | ||
123 | /* Read was is supposed to be the ELF header. Read the initial | |
124 | bytes to determine whether this is a 32 or 64 bit file. */ | |
125 | char ident[EI_NIDENT]; | |
126 | if (read (fd, ident, EI_NIDENT) != EI_NIDENT) | |
127 | { | |
128 | printf ("%s: read error: %m\n", fname); | |
129 | close (fd); | |
130 | return 1; | |
131 | } | |
132 | ||
133 | if (memcmp (&ident[EI_MAG0], ELFMAG, SELFMAG) != 0) | |
134 | { | |
135 | printf ("%s: not an ELF file\n", fname); | |
136 | close (fd); | |
137 | return 1; | |
138 | } | |
139 | ||
140 | int result; | |
141 | if (ident[EI_CLASS] == ELFCLASS64) | |
142 | result = handle_file64 (fname, fd); | |
143 | else | |
144 | result = handle_file32 (fname, fd); | |
145 | ||
146 | close (fd); | |
147 | ||
148 | return result; | |
149 | } | |
150 | ||
151 | ||
152 | int | |
153 | main (int argc, char *argv[]) | |
154 | { | |
155 | int cnt; | |
156 | int result = 0; | |
157 | ||
68dc9497 AS |
158 | for (cnt = 1; cnt < argc; ++cnt) |
159 | result |= handle_file (argv[cnt]); | |
774f5a30 UD |
160 | return result; |
161 | } | |
162 | #endif |