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688903eb | 1 | /* Copyright (C) 1999-2018 Free Software Foundation, Inc. |
591e1ffb UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Andreas Jaeger <aj@suse.de>, 1999 and | |
4 | Jakub Jelinek <jakub@redhat.com>, 1999. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
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. | |
591e1ffb UD |
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 | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
591e1ffb | 15 | |
41bdb6e2 | 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/>. */ | |
591e1ffb UD |
19 | |
20 | /* This code is a heavily simplified version of the readelf program | |
21 | that's part of the current binutils development version. For architectures | |
22 | which need to handle both 32bit and 64bit ELF libraries, this file is | |
23 | included twice for each arch size. */ | |
24 | ||
dc95d158 AJ |
25 | /* check_ptr checks that a pointer is in the mmaped file and doesn't |
26 | point outside it. */ | |
a0f5c800 | 27 | #undef check_ptr |
dc95d158 AJ |
28 | #define check_ptr(ptr) \ |
29 | do \ | |
30 | { \ | |
31 | if ((void *)(ptr) < file_contents \ | |
32 | || (void *)(ptr) > (file_contents+file_length)) \ | |
33 | { \ | |
34 | error (0, 0, _("file %s is truncated\n"), file_name); \ | |
35 | return 1; \ | |
36 | } \ | |
37 | } \ | |
38 | while (0); | |
c98d82db | 39 | |
591e1ffb UD |
40 | /* Returns 0 if everything is ok, != 0 in case of error. */ |
41 | int | |
dc95d158 | 42 | process_elf_file (const char *file_name, const char *lib, int *flag, |
a986484f UD |
43 | unsigned int *osversion, char **soname, void *file_contents, |
44 | size_t file_length) | |
591e1ffb UD |
45 | { |
46 | int i; | |
47 | unsigned int j; | |
c98d82db | 48 | ElfW(Addr) loadaddr; |
591e1ffb UD |
49 | unsigned int dynamic_addr; |
50 | size_t dynamic_size; | |
51 | char *program_interpreter; | |
c98d82db | 52 | |
591e1ffb UD |
53 | ElfW(Ehdr) *elf_header; |
54 | ElfW(Phdr) *elf_pheader, *segment; | |
55 | ElfW(Dyn) *dynamic_segment, *dyn_entry; | |
c98d82db | 56 | char *dynamic_strings; |
591e1ffb UD |
57 | |
58 | elf_header = (ElfW(Ehdr) *) file_contents; | |
a986484f | 59 | *osversion = 0; |
591e1ffb UD |
60 | |
61 | if (elf_header->e_ident [EI_CLASS] != ElfW (CLASS)) | |
62 | { | |
63 | if (opt_verbose) | |
64 | { | |
63fb40b3 | 65 | if (elf_header->e_ident [EI_CLASS] == ELFCLASS32) |
591e1ffb | 66 | error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name); |
63fb40b3 | 67 | else if (elf_header->e_ident [EI_CLASS] == ELFCLASS64) |
591e1ffb UD |
68 | error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name); |
69 | else | |
70 | error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name); | |
71 | } | |
72 | return 1; | |
73 | } | |
74 | ||
75 | if (elf_header->e_type != ET_DYN) | |
76 | { | |
77 | error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name, | |
78 | elf_header->e_type); | |
79 | return 1; | |
80 | } | |
c98d82db | 81 | |
591e1ffb UD |
82 | /* Get information from elf program header. */ |
83 | elf_pheader = (ElfW(Phdr) *) (elf_header->e_phoff + file_contents); | |
dc95d158 | 84 | check_ptr (elf_pheader); |
591e1ffb UD |
85 | |
86 | /* The library is an elf library, now search for soname and | |
87 | libc5/libc6. */ | |
88 | *flag = FLAG_ELF; | |
c98d82db | 89 | |
591e1ffb UD |
90 | loadaddr = -1; |
91 | dynamic_addr = 0; | |
92 | dynamic_size = 0; | |
93 | program_interpreter = NULL; | |
94 | for (i = 0, segment = elf_pheader; | |
95 | i < elf_header->e_phnum; i++, segment++) | |
96 | { | |
dc95d158 AJ |
97 | check_ptr (segment); |
98 | ||
591e1ffb UD |
99 | switch (segment->p_type) |
100 | { | |
101 | case PT_LOAD: | |
b25a62a8 | 102 | if (loadaddr == (ElfW(Addr)) -1) |
459c2eef | 103 | loadaddr = segment->p_vaddr - segment->p_offset; |
591e1ffb UD |
104 | break; |
105 | ||
106 | case PT_DYNAMIC: | |
107 | if (dynamic_addr) | |
108 | error (0, 0, _("more than one dynamic segment\n")); | |
109 | ||
110 | dynamic_addr = segment->p_offset; | |
111 | dynamic_size = segment->p_filesz; | |
112 | break; | |
a986484f | 113 | |
591e1ffb UD |
114 | case PT_INTERP: |
115 | program_interpreter = (char *) (file_contents + segment->p_offset); | |
dc95d158 | 116 | check_ptr (program_interpreter); |
591e1ffb UD |
117 | |
118 | /* Check if this is enough to classify the binary. */ | |
119 | for (j = 0; j < sizeof (interpreters) / sizeof (interpreters [0]); | |
120 | ++j) | |
121 | if (strcmp (program_interpreter, interpreters[j].soname) == 0) | |
122 | { | |
123 | *flag = interpreters[j].flag; | |
124 | break; | |
125 | } | |
126 | break; | |
a986484f UD |
127 | |
128 | case PT_NOTE: | |
0e508a6e | 129 | if (!*osversion && segment->p_filesz >= 32 && segment->p_align >= 4) |
a986484f UD |
130 | { |
131 | ElfW(Word) *abi_note = (ElfW(Word) *) (file_contents | |
132 | + segment->p_offset); | |
0e508a6e | 133 | ElfW(Addr) size = segment->p_filesz; |
8d81ce0c L |
134 | /* NB: Some PT_NOTE segment may have alignment value of 0 |
135 | or 1. gABI specifies that PT_NOTE segments should be | |
136 | aligned to 4 bytes in 32-bit objects and to 8 bytes in | |
137 | 64-bit objects. As a Linux extension, we also support | |
138 | 4 byte alignment in 64-bit objects. If p_align is less | |
139 | than 4, we treate alignment as 4 bytes since some note | |
140 | segments have 0 or 1 byte alignment. */ | |
141 | ElfW(Addr) align = segment->p_align; | |
142 | if (align < 4) | |
143 | align = 4; | |
144 | else if (align != 4 && align != 8) | |
145 | continue; | |
0e508a6e UD |
146 | |
147 | while (abi_note [0] != 4 || abi_note [1] != 16 | |
148 | || abi_note [2] != 1 | |
149 | || memcmp (abi_note + 3, "GNU", 4) != 0) | |
150 | { | |
8d81ce0c L |
151 | ElfW(Addr) note_size |
152 | = ELF_NOTE_NEXT_OFFSET (abi_note[0], abi_note[1], | |
153 | align); | |
0e508a6e UD |
154 | |
155 | if (size - 32 < note_size || note_size == 0) | |
156 | { | |
157 | size = 0; | |
158 | break; | |
159 | } | |
160 | size -= note_size; | |
161 | abi_note = (void *) abi_note + note_size; | |
162 | } | |
163 | ||
164 | if (size == 0) | |
165 | break; | |
166 | ||
167 | *osversion = (abi_note [4] << 24) | | |
168 | ((abi_note [5] & 0xff) << 16) | | |
169 | ((abi_note [6] & 0xff) << 8) | | |
170 | (abi_note [7] & 0xff); | |
a986484f UD |
171 | } |
172 | break; | |
173 | ||
591e1ffb UD |
174 | default: |
175 | break; | |
176 | } | |
c98d82db | 177 | |
591e1ffb | 178 | } |
b25a62a8 | 179 | if (loadaddr == (ElfW(Addr)) -1) |
591e1ffb UD |
180 | { |
181 | /* Very strange. */ | |
182 | loadaddr = 0; | |
183 | } | |
184 | ||
185 | /* Now we can read the dynamic sections. */ | |
186 | if (dynamic_size == 0) | |
187 | return 1; | |
c98d82db | 188 | |
591e1ffb | 189 | dynamic_segment = (ElfW(Dyn) *) (file_contents + dynamic_addr); |
dc95d158 | 190 | check_ptr (dynamic_segment); |
591e1ffb UD |
191 | |
192 | /* Find the string table. */ | |
193 | dynamic_strings = NULL; | |
194 | for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL; | |
195 | ++dyn_entry) | |
196 | { | |
dc95d158 | 197 | check_ptr (dyn_entry); |
591e1ffb UD |
198 | if (dyn_entry->d_tag == DT_STRTAB) |
199 | { | |
200 | dynamic_strings = (char *) (file_contents + dyn_entry->d_un.d_val - loadaddr); | |
dc95d158 | 201 | check_ptr (dynamic_strings); |
591e1ffb UD |
202 | break; |
203 | } | |
204 | } | |
205 | ||
206 | if (dynamic_strings == NULL) | |
207 | return 1; | |
208 | ||
209 | /* Now read the DT_NEEDED and DT_SONAME entries. */ | |
210 | for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL; | |
211 | ++dyn_entry) | |
212 | { | |
213 | if (dyn_entry->d_tag == DT_NEEDED || dyn_entry->d_tag == DT_SONAME) | |
214 | { | |
215 | char *name = dynamic_strings + dyn_entry->d_un.d_val; | |
dc95d158 | 216 | check_ptr (name); |
591e1ffb UD |
217 | |
218 | if (dyn_entry->d_tag == DT_NEEDED) | |
219 | { | |
c98d82db | 220 | |
591e1ffb UD |
221 | if (*flag == FLAG_ELF) |
222 | { | |
223 | /* Check if this is enough to classify the binary. */ | |
224 | for (j = 0; | |
225 | j < sizeof (known_libs) / sizeof (known_libs [0]); | |
226 | ++j) | |
227 | if (strcmp (name, known_libs [j].soname) == 0) | |
228 | { | |
229 | *flag = known_libs [j].flag; | |
230 | break; | |
231 | } | |
232 | } | |
233 | } | |
234 | ||
235 | else if (dyn_entry->d_tag == DT_SONAME) | |
236 | *soname = xstrdup (name); | |
c98d82db | 237 | |
591e1ffb UD |
238 | /* Do we have everything we need? */ |
239 | if (*soname && *flag != FLAG_ELF) | |
240 | return 0; | |
241 | } | |
242 | } | |
243 | ||
591e1ffb UD |
244 | return 0; |
245 | } |