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581c785b | 1 | /* Copyright (C) 1999-2022 Free Software Foundation, Inc. |
591e1ffb | 2 | This file is part of the GNU C Library. |
591e1ffb UD |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
591e1ffb UD |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
591e1ffb | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
591e1ffb | 17 | |
efbbd9c3 L |
18 | #include <elf-read-prop.h> |
19 | ||
591e1ffb UD |
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, |
c628c229 AZ |
43 | unsigned int *isa_level, char **soname, void *file_contents, |
44 | size_t file_length) | |
591e1ffb UD |
45 | { |
46 | int i; | |
591e1ffb UD |
47 | unsigned int dynamic_addr; |
48 | size_t dynamic_size; | |
49 | char *program_interpreter; | |
c98d82db | 50 | |
591e1ffb UD |
51 | ElfW(Ehdr) *elf_header; |
52 | ElfW(Phdr) *elf_pheader, *segment; | |
53 | ElfW(Dyn) *dynamic_segment, *dyn_entry; | |
c98d82db | 54 | char *dynamic_strings; |
591e1ffb UD |
55 | |
56 | elf_header = (ElfW(Ehdr) *) file_contents; | |
57 | ||
58 | if (elf_header->e_ident [EI_CLASS] != ElfW (CLASS)) | |
59 | { | |
60 | if (opt_verbose) | |
61 | { | |
63fb40b3 | 62 | if (elf_header->e_ident [EI_CLASS] == ELFCLASS32) |
591e1ffb | 63 | error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name); |
63fb40b3 | 64 | else if (elf_header->e_ident [EI_CLASS] == ELFCLASS64) |
591e1ffb UD |
65 | error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name); |
66 | else | |
67 | error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name); | |
68 | } | |
69 | return 1; | |
70 | } | |
71 | ||
72 | if (elf_header->e_type != ET_DYN) | |
73 | { | |
74 | error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name, | |
75 | elf_header->e_type); | |
76 | return 1; | |
77 | } | |
c98d82db | 78 | |
591e1ffb UD |
79 | /* Get information from elf program header. */ |
80 | elf_pheader = (ElfW(Phdr) *) (elf_header->e_phoff + file_contents); | |
dc95d158 | 81 | check_ptr (elf_pheader); |
591e1ffb | 82 | |
8ee87859 LM |
83 | /* The library is an elf library. */ |
84 | *flag = FLAG_ELF_LIBC6; | |
c98d82db | 85 | |
efbbd9c3 L |
86 | /* The default ISA level is 0. */ |
87 | *isa_level = 0; | |
88 | ||
591e1ffb UD |
89 | dynamic_addr = 0; |
90 | dynamic_size = 0; | |
91 | program_interpreter = NULL; | |
92 | for (i = 0, segment = elf_pheader; | |
93 | i < elf_header->e_phnum; i++, segment++) | |
94 | { | |
dc95d158 AJ |
95 | check_ptr (segment); |
96 | ||
591e1ffb UD |
97 | switch (segment->p_type) |
98 | { | |
591e1ffb UD |
99 | case PT_DYNAMIC: |
100 | if (dynamic_addr) | |
101 | error (0, 0, _("more than one dynamic segment\n")); | |
102 | ||
103 | dynamic_addr = segment->p_offset; | |
104 | dynamic_size = segment->p_filesz; | |
105 | break; | |
a986484f | 106 | |
591e1ffb UD |
107 | case PT_INTERP: |
108 | program_interpreter = (char *) (file_contents + segment->p_offset); | |
dc95d158 | 109 | check_ptr (program_interpreter); |
591e1ffb | 110 | |
efbbd9c3 L |
111 | case PT_GNU_PROPERTY: |
112 | /* The NT_GNU_PROPERTY_TYPE_0 note must be aligned to 4 bytes | |
113 | in 32-bit objects and to 8 bytes in 64-bit objects. Skip | |
114 | notes with incorrect alignment. */ | |
115 | if (segment->p_align == (__ELF_NATIVE_CLASS / 8)) | |
116 | { | |
117 | const ElfW(Nhdr) *note = (const void *) (file_contents | |
118 | + segment->p_offset); | |
119 | const ElfW(Addr) size = segment->p_filesz; | |
120 | const ElfW(Addr) align = segment->p_align; | |
121 | ||
122 | const ElfW(Addr) start = (ElfW(Addr)) (uintptr_t) note; | |
123 | unsigned int last_type = 0; | |
124 | ||
125 | while ((ElfW(Addr)) (uintptr_t) (note + 1) - start < size) | |
126 | { | |
127 | /* Find the NT_GNU_PROPERTY_TYPE_0 note. */ | |
128 | if (note->n_namesz == 4 | |
129 | && note->n_type == NT_GNU_PROPERTY_TYPE_0 | |
130 | && memcmp (note + 1, "GNU", 4) == 0) | |
131 | { | |
132 | /* Check for invalid property. */ | |
133 | if (note->n_descsz < 8 | |
134 | || (note->n_descsz % sizeof (ElfW(Addr))) != 0) | |
135 | goto done; | |
136 | ||
137 | /* Start and end of property array. */ | |
138 | unsigned char *ptr = (unsigned char *) (note + 1) + 4; | |
139 | unsigned char *ptr_end = ptr + note->n_descsz; | |
140 | ||
141 | do | |
142 | { | |
143 | unsigned int type = *(unsigned int *) ptr; | |
144 | unsigned int datasz = *(unsigned int *) (ptr + 4); | |
145 | ||
146 | /* Property type must be in ascending order. */ | |
147 | if (type < last_type) | |
148 | goto done; | |
149 | ||
150 | ptr += 8; | |
151 | if ((ptr + datasz) > ptr_end) | |
152 | goto done; | |
153 | ||
154 | last_type = type; | |
155 | ||
156 | /* Target specific property processing. | |
157 | Return value: | |
158 | false: Continue processing the properties. | |
159 | true : Stop processing the properties. | |
160 | */ | |
161 | if (read_gnu_property (isa_level, type, | |
162 | datasz, ptr)) | |
163 | goto done; | |
164 | ||
165 | /* Check the next property item. */ | |
166 | ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr))); | |
167 | } | |
168 | while ((ptr_end - ptr) >= 8); | |
169 | ||
170 | /* Only handle one NT_GNU_PROPERTY_TYPE_0. */ | |
171 | goto done; | |
172 | } | |
173 | ||
174 | note = ((const void *) note | |
175 | + ELF_NOTE_NEXT_OFFSET (note->n_namesz, | |
176 | note->n_descsz, | |
177 | align)); | |
178 | } | |
179 | } | |
180 | done: | |
181 | break; | |
182 | ||
591e1ffb UD |
183 | default: |
184 | break; | |
185 | } | |
c98d82db | 186 | |
591e1ffb | 187 | } |
591e1ffb UD |
188 | |
189 | /* Now we can read the dynamic sections. */ | |
190 | if (dynamic_size == 0) | |
191 | return 1; | |
c98d82db | 192 | |
591e1ffb | 193 | dynamic_segment = (ElfW(Dyn) *) (file_contents + dynamic_addr); |
dc95d158 | 194 | check_ptr (dynamic_segment); |
591e1ffb UD |
195 | |
196 | /* Find the string table. */ | |
197 | dynamic_strings = NULL; | |
198 | for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL; | |
199 | ++dyn_entry) | |
200 | { | |
dc95d158 | 201 | check_ptr (dyn_entry); |
591e1ffb UD |
202 | if (dyn_entry->d_tag == DT_STRTAB) |
203 | { | |
58e8f5fd AS |
204 | /* Find the file offset of the segment containing the dynamic |
205 | string table. */ | |
206 | ElfW(Off) loadoff = -1; | |
207 | for (i = 0, segment = elf_pheader; | |
208 | i < elf_header->e_phnum; i++, segment++) | |
209 | { | |
210 | if (segment->p_type == PT_LOAD | |
211 | && dyn_entry->d_un.d_val >= segment->p_vaddr | |
212 | && (dyn_entry->d_un.d_val - segment->p_vaddr | |
213 | < segment->p_filesz)) | |
214 | { | |
215 | loadoff = segment->p_vaddr - segment->p_offset; | |
216 | break; | |
217 | } | |
218 | } | |
219 | if (loadoff == (ElfW(Off)) -1) | |
220 | { | |
221 | /* Very strange. */ | |
222 | loadoff = 0; | |
223 | } | |
224 | ||
225 | dynamic_strings = (char *) (file_contents + dyn_entry->d_un.d_val | |
226 | - loadoff); | |
dc95d158 | 227 | check_ptr (dynamic_strings); |
591e1ffb UD |
228 | break; |
229 | } | |
230 | } | |
231 | ||
232 | if (dynamic_strings == NULL) | |
233 | return 1; | |
234 | ||
8ee87859 | 235 | /* Now read the DT_SONAME entries. */ |
591e1ffb UD |
236 | for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL; |
237 | ++dyn_entry) | |
238 | { | |
8ee87859 | 239 | if (dyn_entry->d_tag == DT_SONAME) |
591e1ffb UD |
240 | { |
241 | char *name = dynamic_strings + dyn_entry->d_un.d_val; | |
dc95d158 | 242 | check_ptr (name); |
8ee87859 LM |
243 | *soname = xstrdup (name); |
244 | return 0; | |
591e1ffb UD |
245 | } |
246 | } | |
247 | ||
591e1ffb UD |
248 | return 0; |
249 | } |