1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
|
/* $OpenBSD: rtld_machine.c,v 1.8 2005/09/22 01:33:08 drahn Exp $ */
/*
* Copyright (c) 1998-2004 Opsycon AB, Sweden.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#define _DYN_LOADER
#include <sys/types.h>
#include <sys/mman.h>
#include <link.h>
#include "resolve.h"
#include "syscall.h"
#include "archdep.h"
int
_dl_md_reloc(elf_object_t *object, int rel, int relsz)
{
int i;
int numrel;
int fails = 0;
struct load_list *load_list;
Elf64_Addr loff;
Elf64_Addr ooff;
Elf64_Addr got_start, got_end;
Elf64_Rel *relocs;
const Elf64_Sym *sym, *this;
loff = object->load_offs;
numrel = object->Dyn.info[relsz] / sizeof(Elf64_Rel);
relocs = (Elf64_Rel *)(object->Dyn.info[rel]);
if (relocs == NULL)
return(0);
/*
* Change protection of all write protected segments in the
* object so we can do relocations in the .rodata section.
* After relocation restore protection.
*/
load_list = object->load_list;
while (load_list != NULL) {
if ((load_list->prot & PROT_WRITE) == 0)
_dl_mprotect(load_list->start, load_list->size,
load_list->prot|PROT_WRITE);
load_list = load_list->next;
}
/* XXX We need the got limits to know if reloc is in got. */
/* XXX Relocs against the got should not include the STUB address! */
this = NULL;
got_start = 0;
got_end = 0;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
got_start = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__got_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
got_end = ooff + this->st_value;
DL_DEB(("relocating %d\n", numrel));
for (i = 0; i < numrel; i++, relocs++) {
Elf64_Addr r_addr = relocs->r_offset + loff;
const char *symn;
int type;
if (ELF64_R_SYM(relocs->r_info) == 0xffffff)
continue;
ooff = 0;
sym = object->dyn.symtab;
sym += ELF64_R_SYM(relocs->r_info);
symn = object->dyn.strtab + sym->st_name;
type = ELF64_R_TYPE(relocs->r_info);
this = NULL;
if (ELF64_R_SYM(relocs->r_info) &&
!(ELF64_ST_BIND(sym->st_info) == STB_LOCAL &&
ELF64_ST_TYPE (sym->st_info) == STT_NOTYPE)) {
ooff = _dl_find_symbol(symn, &this,
SYM_SEARCH_ALL | SYM_WARNNOTFOUND | SYM_PLT,
sym, object, NULL);
if (this == NULL) {
if (ELF_ST_BIND(sym->st_info) != STB_WEAK)
fails++;
continue;
}
}
switch (ELF64_R_TYPE(relocs->r_info)) {
/* XXX Handle non aligned relocs. .eh_frame
* XXX in libstdc++ seems to have them... */
u_int64_t robj;
case R_MIPS_REL32_64:
if (ELF64_ST_BIND(sym->st_info) == STB_LOCAL &&
(ELF64_ST_TYPE(sym->st_info) == STT_SECTION ||
ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE) ) {
if ((long)r_addr & 7) {
_dl_bcopy((char *)r_addr, &robj, sizeof(robj));
robj += loff + sym->st_value;
_dl_bcopy(&robj, (char *)r_addr, sizeof(robj));
} else {
*(u_int64_t *)r_addr += loff + sym->st_value;
}
} else if (this && ((long)r_addr & 7)) {
_dl_bcopy((char *)r_addr, &robj, sizeof(robj));
robj += this->st_value + ooff;
_dl_bcopy(&robj, (char *)r_addr, sizeof(robj));
} else if (this) {
*(u_int64_t *)r_addr += this->st_value + ooff;
}
break;
case R_MIPS_NONE:
break;
default:
_dl_printf("%s: unsupported relocation '%d'\n",
_dl_progname, ELF64_R_TYPE(relocs->r_info));
_dl_exit(1);
}
}
DL_DEB(("done %d fails\n", fails));
load_list = object->load_list;
while (load_list != NULL) {
if ((load_list->prot & PROT_WRITE) == 0)
_dl_mprotect(load_list->start, load_list->size,
load_list->prot);
load_list = load_list->next;
}
return(fails);
}
/*
* Relocate the Global Offset Table (GOT). Currently we don't
* do lazy evaluation here because the GNU linker doesn't
* follow the ABI spec which says that if an external symbol
* is referenced by other relocations than CALL16 and 26 it
* should not be given a stub and have a zero value in the
* symbol table. By not doing so, we can't use pointers to
* external functions and use them in comparisons...
*/
void
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
int i, n;
Elf64_Addr loff;
Elf64_Addr ooff;
Elf64_Addr *gotp;
const Elf64_Sym *symp;
const Elf64_Sym *this;
const char *strt;
if (object->status & STAT_GOT_DONE)
return;
lazy = 0; /* XXX Fix ld before enabling lazy */
loff = object->load_offs;
strt = object->dyn.strtab;
gotp = object->dyn.pltgot;
n = object->Dyn.info[DT_MIPS_LOCAL_GOTNO - DT_LOPROC + DT_NUM];
DL_DEB(("loff: '%p'\n", loff));
/*
* Set up pointers for run time (lazy) resolving.
*/
gotp[0] = (long)_dl_rt_resolve;
if (gotp[1] & 0x0000000080000000) {
gotp[1] = (long)object | 0x0000000080000000;
}
/* First do all local references. */
for (i = ((gotp[1] & 0x0000000080000000) ? 2 : 1); i < n; i++) {
gotp[i] += loff;
}
gotp += n;
symp = object->dyn.symtab;
symp += object->Dyn.info[DT_MIPS_GOTSYM - DT_LOPROC + DT_NUM];
n = object->Dyn.info[DT_MIPS_SYMTABNO - DT_LOPROC + DT_NUM] -
object->Dyn.info[DT_MIPS_GOTSYM - DT_LOPROC + DT_NUM];
this = NULL;
object->plt_size = 0;
object->got_size = 0;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_start = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__got_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_size = ooff + this->st_value - object->got_start;
/*
* Then do all global references according to the ABI.
* Quickstart is not yet implemented.
*/
while (n--) {
if (symp->st_shndx == SHN_UNDEF &&
ELF64_ST_TYPE(symp->st_info) == STT_FUNC) {
if (symp->st_value == 0 || !lazy) {
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name,
&this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
} else
*gotp = symp->st_value + ooff;
} else if (symp->st_shndx == SHN_COMMON ||
symp->st_shndx == SHN_UNDEF) {
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name, &this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
} else if (ELF64_ST_TYPE(symp->st_info) == STT_FUNC &&
symp->st_value != *gotp) {
*gotp += loff;
} else { /* Resolve all others immediatly */
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name, &this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
else
*gotp = symp->st_value + loff;
}
gotp++;
symp++;
}
object->status |= STAT_GOT_DONE;
DL_DEB(("got: %x, %x\n", object->got_start, object->got_size));
if (object->got_size != 0)
_dl_mprotect((void*)object->got_start, object->got_size,
PROT_READ);
}
|
