1 /*-
2 * Copyright (c) 2015-2017 Ruslan Bukin <[email protected]>
3 * All rights reserved.
4 *
5 * This software was developed by SRI International and the University of
6 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
7 * ("CTSRD"), as part of the DARPA CRASH research programme.
8 *
9 * This software was developed by the University of Cambridge Computer
10 * Laboratory as part of the CTSRD Project, with support from the UK Higher
11 * Education Innovation Fund (HEIF).
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37
38 #include <sys/types.h>
39
40 #include <stdlib.h>
41
42 #include "debug.h"
43 #include "rtld.h"
44 #include "rtld_printf.h"
45
46 /*
47 * It is possible for the compiler to emit relocations for unaligned data.
48 * We handle this situation with these inlines.
49 */
50 #define RELOC_ALIGNED_P(x) \
51 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
52
53 uint64_t
set_gp(Obj_Entry * obj)54 set_gp(Obj_Entry *obj)
55 {
56 uint64_t old;
57 SymLook req;
58 uint64_t gp;
59 int res;
60
61 __asm __volatile("mv %0, gp" : "=r"(old));
62
63 symlook_init(&req, "__global_pointer$");
64 req.ventry = NULL;
65 req.flags = SYMLOOK_EARLY;
66 res = symlook_obj(&req, obj);
67
68 if (res == 0) {
69 gp = req.sym_out->st_value;
70 __asm __volatile("mv gp, %0" :: "r"(gp));
71 }
72
73 return (old);
74 }
75
76 void
init_pltgot(Obj_Entry * obj)77 init_pltgot(Obj_Entry *obj)
78 {
79
80 if (obj->pltgot != NULL) {
81 obj->pltgot[0] = (Elf_Addr)&_rtld_bind_start;
82 obj->pltgot[1] = (Elf_Addr)obj;
83 }
84 }
85
86 int
do_copy_relocations(Obj_Entry * dstobj)87 do_copy_relocations(Obj_Entry *dstobj)
88 {
89 const Obj_Entry *srcobj, *defobj;
90 const Elf_Rela *relalim;
91 const Elf_Rela *rela;
92 const Elf_Sym *srcsym;
93 const Elf_Sym *dstsym;
94 const void *srcaddr;
95 const char *name;
96 void *dstaddr;
97 SymLook req;
98 size_t size;
99 int res;
100
101 /*
102 * COPY relocs are invalid outside of the main program
103 */
104 assert(dstobj->mainprog);
105
106 relalim = (const Elf_Rela *)((const char *)dstobj->rela +
107 dstobj->relasize);
108 for (rela = dstobj->rela; rela < relalim; rela++) {
109 if (ELF_R_TYPE(rela->r_info) != R_RISCV_COPY)
110 continue;
111
112 dstaddr = (void *)(dstobj->relocbase + rela->r_offset);
113 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
114 name = dstobj->strtab + dstsym->st_name;
115 size = dstsym->st_size;
116
117 symlook_init(&req, name);
118 req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
119 req.flags = SYMLOOK_EARLY;
120
121 for (srcobj = globallist_next(dstobj); srcobj != NULL;
122 srcobj = globallist_next(srcobj)) {
123 res = symlook_obj(&req, srcobj);
124 if (res == 0) {
125 srcsym = req.sym_out;
126 defobj = req.defobj_out;
127 break;
128 }
129 }
130 if (srcobj == NULL) {
131 _rtld_error(
132 "Undefined symbol \"%s\" referenced from COPY relocation in %s",
133 name, dstobj->path);
134 return (-1);
135 }
136
137 srcaddr = (const void *)(defobj->relocbase + srcsym->st_value);
138 memcpy(dstaddr, srcaddr, size);
139 }
140
141 return (0);
142 }
143
144 /*
145 * Process the PLT relocations.
146 */
147 int
reloc_plt(Obj_Entry * obj,int flags __unused,RtldLockState * lockstate __unused)148 reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)
149 {
150 const Elf_Rela *relalim;
151 const Elf_Rela *rela;
152
153 relalim = (const Elf_Rela *)((const char *)obj->pltrela +
154 obj->pltrelasize);
155 for (rela = obj->pltrela; rela < relalim; rela++) {
156 Elf_Addr *where;
157
158 assert(ELF_R_TYPE(rela->r_info) == R_RISCV_JUMP_SLOT);
159
160 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
161 *where += (Elf_Addr)obj->relocbase;
162 }
163
164 return (0);
165 }
166
167 /*
168 * LD_BIND_NOW was set - force relocation for all jump slots
169 */
170 int
reloc_jmpslots(Obj_Entry * obj,int flags,RtldLockState * lockstate)171 reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
172 {
173 const Obj_Entry *defobj;
174 const Elf_Rela *relalim;
175 const Elf_Rela *rela;
176 const Elf_Sym *def;
177
178 relalim = (const Elf_Rela *)((const char *)obj->pltrela +
179 obj->pltrelasize);
180 for (rela = obj->pltrela; rela < relalim; rela++) {
181 Elf_Addr *where;
182
183 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
184 switch(ELF_R_TYPE(rela->r_info)) {
185 case R_RISCV_JUMP_SLOT:
186 def = find_symdef(ELF_R_SYM(rela->r_info), obj,
187 &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate);
188 if (def == NULL) {
189 dbg("reloc_jmpslots: sym not found");
190 return (-1);
191 }
192
193 *where = (Elf_Addr)(defobj->relocbase + def->st_value);
194 break;
195 default:
196 _rtld_error("Unknown relocation type %x in jmpslot",
197 (unsigned int)ELF_R_TYPE(rela->r_info));
198 return (-1);
199 }
200 }
201
202 return (0);
203 }
204
205 int
reloc_iresolve(Obj_Entry * obj __unused,struct Struct_RtldLockState * lockstate __unused)206 reloc_iresolve(Obj_Entry *obj __unused,
207 struct Struct_RtldLockState *lockstate __unused)
208 {
209
210 /* XXX not implemented */
211 return (0);
212 }
213
214 int
reloc_gnu_ifunc(Obj_Entry * obj __unused,int flags __unused,struct Struct_RtldLockState * lockstate __unused)215 reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused,
216 struct Struct_RtldLockState *lockstate __unused)
217 {
218
219 /* XXX not implemented */
220 return (0);
221 }
222
223 Elf_Addr
reloc_jmpslot(Elf_Addr * where,Elf_Addr target,const Obj_Entry * defobj __unused,const Obj_Entry * obj __unused,const Elf_Rel * rel)224 reloc_jmpslot(Elf_Addr *where, Elf_Addr target,
225 const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused,
226 const Elf_Rel *rel)
227 {
228
229 assert(ELF_R_TYPE(rel->r_info) == R_RISCV_JUMP_SLOT);
230
231 if (*where != target && !ld_bind_not)
232 *where = target;
233 return (target);
234 }
235
236 /*
237 * Process non-PLT relocations
238 */
239 int
reloc_non_plt(Obj_Entry * obj,Obj_Entry * obj_rtld,int flags,RtldLockState * lockstate)240 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
241 RtldLockState *lockstate)
242 {
243 const Obj_Entry *defobj;
244 const Elf_Rela *relalim;
245 const Elf_Rela *rela;
246 const Elf_Sym *def;
247 SymCache *cache;
248 Elf_Addr *where;
249 unsigned long symnum;
250
251 if ((flags & SYMLOOK_IFUNC) != 0)
252 /* XXX not implemented */
253 return (0);
254
255 /*
256 * The dynamic loader may be called from a thread, we have
257 * limited amounts of stack available so we cannot use alloca().
258 */
259 if (obj == obj_rtld)
260 cache = NULL;
261 else
262 cache = calloc(obj->dynsymcount, sizeof(SymCache));
263 /* No need to check for NULL here */
264
265 relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize);
266 for (rela = obj->rela; rela < relalim; rela++) {
267 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
268 symnum = ELF_R_SYM(rela->r_info);
269
270 switch (ELF_R_TYPE(rela->r_info)) {
271 case R_RISCV_JUMP_SLOT:
272 /* This will be handled by the plt/jmpslot routines */
273 break;
274 case R_RISCV_NONE:
275 break;
276 case R_RISCV_64:
277 def = find_symdef(symnum, obj, &defobj, flags, cache,
278 lockstate);
279 if (def == NULL)
280 return (-1);
281
282 *where = (Elf_Addr)(defobj->relocbase + def->st_value +
283 rela->r_addend);
284 break;
285 case R_RISCV_TLS_DTPMOD64:
286 def = find_symdef(symnum, obj, &defobj, flags, cache,
287 lockstate);
288 if (def == NULL)
289 return -1;
290
291 *where += (Elf_Addr)defobj->tlsindex;
292 break;
293 case R_RISCV_COPY:
294 /*
295 * These are deferred until all other relocations have
296 * been done. All we do here is make sure that the
297 * COPY relocation is not in a shared library. They
298 * are allowed only in executable files.
299 */
300 if (!obj->mainprog) {
301 _rtld_error("%s: Unexpected R_RISCV_COPY "
302 "relocation in shared library", obj->path);
303 return (-1);
304 }
305 break;
306 case R_RISCV_TLS_DTPREL64:
307 def = find_symdef(symnum, obj, &defobj, flags, cache,
308 lockstate);
309 if (def == NULL)
310 return (-1);
311 /*
312 * We lazily allocate offsets for static TLS as we
313 * see the first relocation that references the
314 * TLS block. This allows us to support (small
315 * amounts of) static TLS in dynamically loaded
316 * modules. If we run out of space, we generate an
317 * error.
318 */
319 if (!defobj->tls_done) {
320 if (!allocate_tls_offset(
321 __DECONST(Obj_Entry *, defobj))) {
322 _rtld_error(
323 "%s: No space available for static "
324 "Thread Local Storage", obj->path);
325 return (-1);
326 }
327 }
328
329 *where += (Elf_Addr)(def->st_value + rela->r_addend
330 - TLS_DTV_OFFSET);
331 break;
332 case R_RISCV_TLS_TPREL64:
333 def = find_symdef(symnum, obj, &defobj, flags, cache,
334 lockstate);
335 if (def == NULL)
336 return (-1);
337
338 /*
339 * We lazily allocate offsets for static TLS as we
340 * see the first relocation that references the
341 * TLS block. This allows us to support (small
342 * amounts of) static TLS in dynamically loaded
343 * modules. If we run out of space, we generate an
344 * error.
345 */
346 if (!defobj->tls_done) {
347 if (!allocate_tls_offset(
348 __DECONST(Obj_Entry *, defobj))) {
349 _rtld_error(
350 "%s: No space available for static "
351 "Thread Local Storage", obj->path);
352 return (-1);
353 }
354 }
355
356 *where = (def->st_value + rela->r_addend +
357 defobj->tlsoffset - TLS_TP_OFFSET);
358 break;
359 case R_RISCV_RELATIVE:
360 *where = (Elf_Addr)(obj->relocbase + rela->r_addend);
361 break;
362 default:
363 rtld_printf("%s: Unhandled relocation %lu\n",
364 obj->path, ELF_R_TYPE(rela->r_info));
365 return (-1);
366 }
367 }
368
369 return (0);
370 }
371
372 void
ifunc_init(Elf_Auxinfo aux_info[__min_size (AT_COUNT)]__unused)373 ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused)
374 {
375
376 }
377
378 void
pre_init(void)379 pre_init(void)
380 {
381
382 }
383
384 void
allocate_initial_tls(Obj_Entry * objs)385 allocate_initial_tls(Obj_Entry *objs)
386 {
387 Elf_Addr **tp;
388
389 /*
390 * Fix the size of the static TLS block by using the maximum
391 * offset allocated so far and adding a bit for dynamic modules to
392 * use.
393 */
394 tls_static_space = tls_last_offset + tls_last_size +
395 RTLD_STATIC_TLS_EXTRA;
396
397 tp = (Elf_Addr **)((char *)allocate_tls(objs, NULL, TLS_TCB_SIZE, 16)
398 + TLS_TP_OFFSET + TLS_TCB_SIZE);
399
400 __asm __volatile("mv tp, %0" :: "r"(tp));
401 }
402
403 void *
__tls_get_addr(tls_index * ti)404 __tls_get_addr(tls_index* ti)
405 {
406 char *_tp;
407 void *p;
408
409 __asm __volatile("mv %0, tp" : "=r" (_tp));
410
411 p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)_tp - TLS_TP_OFFSET
412 - TLS_TCB_SIZE), ti->ti_module, ti->ti_offset);
413
414 return ((char*)p + TLS_DTV_OFFSET);
415 }
416