1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <assert.h>
18 #include <fcntl.h>
19 #include <gelf.h>
20 #include <libelf.h>
21 #include <sys/types.h>
22 #include <stdbool.h>
23 #include <unistd.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <stdint.h>
27 #include <stdio.h>
28 #include <stddef.h>
29 #include <errno.h>
30 
31 #include <nanohub/nanohub.h>
32 #include <nanohub/nanoapp.h>
33 #include <nanohub/appRelocFormat.h>
34 
35 //This code assumes it is run on a LE CPU with unaligned access abilities. Sorry.
36 
37 #define FLASH_BASE  0x10000000
38 #define RAM_BASE    0x80000000
39 
40 #define FLASH_SIZE  0x10000000  //256MB ought to be enough for everyone
41 #define RAM_SIZE    0x10000000  //256MB ought to be enough for everyone
42 
43 //caution: double evaluation
44 #define IS_IN_RANGE_E(_val, _rstart, _rend) (((_val) >= (_rstart)) && ((_val) < (_rend)))
45 #define IS_IN_RANGE(_val, _rstart, _rsz)    IS_IN_RANGE_E((_val), (_rstart), ((_rstart) + (_rsz)))
46 #define IS_IN_RAM(_val)              IS_IN_RANGE(_val, RAM_BASE, RAM_SIZE)
47 #define IS_IN_FLASH(_val)            IS_IN_RANGE(_val, FLASH_BASE, FLASH_SIZE)
48 
49 
50 #define NANO_RELOC_TYPE_RAM    0
51 #define NANO_RELOC_TYPE_FLASH  1
52 #define NANO_RELOC_LAST        2 //must be <= (RELOC_TYPE_MASK >> RELOC_TYPE_SHIFT)
53 
54 struct RelocEntry {
55     uint32_t where;
56     uint32_t info;  //bottom 8 bits is type, top 24 is sym idx
57 };
58 
59 #define RELOC_TYPE_ABS_S    2
60 #define RELOC_TYPE_ABS_D    21
61 #define RELOC_TYPE_SECT     23
62 
63 
64 struct SymtabEntry {
65     uint32_t a;
66     uint32_t addr;
67     uint32_t b, c;
68 };
69 
70 struct NanoRelocEntry {
71     uint32_t ofstInRam;
72     uint8_t type;
73 };
74 
75 #ifndef ARRAY_SIZE
76 #define ARRAY_SIZE(ary) (sizeof(ary) / sizeof((ary)[0]))
77 #endif
78 
79 #define DBG(fmt, ...) printf(fmt "\n", ##__VA_ARGS__)
80 #define ERR(fmt, ...) fprintf(stderr, fmt "\n", ##__VA_ARGS__)
81 
82 // Prints the given message followed by the most recent libelf error
83 #define ELF_ERR(fmt, ...) ERR(fmt ": %s\n", ##__VA_ARGS__, elf_errmsg(-1))
84 
85 struct ElfAppSection {
86     void  *data;
87     size_t size;
88 };
89 
90 struct ElfNanoApp {
91     struct ElfAppSection flash;
92     struct ElfAppSection data;
93     struct ElfAppSection relocs;
94     struct ElfAppSection symtab;
95 
96     // Not parsed from file, but constructed via genElfNanoRelocs
97     struct ElfAppSection packedNanoRelocs;
98 };
99 
fatalUsage(const char * name,const char * msg,const char * arg)100 static void fatalUsage(const char *name, const char *msg, const char *arg)
101 {
102     if (msg && arg)
103         fprintf(stderr, "Error: %s: %s\n\n", msg, arg);
104     else if (msg)
105         fprintf(stderr, "Error: %s\n\n", msg);
106 
107     fprintf(stderr, "USAGE: %s [-v] [-k <key id>] [-a <app id>] [-r] [-n <layout name>] [-i <layout id>] <input file> [<output file>]\n"
108                     "       -v               : be verbose\n"
109                     "       -n <layout name> : app, os, key\n"
110                     "       -i <layout id>   : 1 (app), 2 (key), 3 (os)\n"
111                     "       -f <layout flags>: 16-bit hex value, stored as layout-specific flags\n"
112                     "       -a <app ID>      : 64-bit hex number != 0\n"
113                     "       -e <app version> : 32-bit hex number\n"
114                     "       -k <key ID>      : 64-bit hex number != 0\n"
115                     "       -r               : bare (no AOSP header); used only for inner OS image generation\n"
116                     "       -s               : treat input as statically linked ELF (app layout only)\n"
117                     "       layout ID and layout name control the same parameter, so only one of them needs to be used\n"
118                     , name);
119     exit(1);
120 }
121 
packNanoRelocs(struct NanoRelocEntry * nanoRelocs,uint32_t outNumRelocs,uint32_t * finalPackedNanoRelocSz,bool verbose)122 static uint8_t *packNanoRelocs(struct NanoRelocEntry *nanoRelocs, uint32_t outNumRelocs, uint32_t *finalPackedNanoRelocSz, bool verbose)
123 {
124     uint32_t i, j, k;
125     uint8_t *packedNanoRelocs;
126     uint32_t packedNanoRelocSz;
127     uint32_t lastOutType = 0, origin = 0;
128 
129     //sort by type and then offset
130     for (i = 0; i < outNumRelocs; i++) {
131         struct NanoRelocEntry t;
132 
133         for (k = i, j = k + 1; j < outNumRelocs; j++) {
134             if (nanoRelocs[j].type > nanoRelocs[k].type)
135                 continue;
136             if ((nanoRelocs[j].type < nanoRelocs[k].type) || (nanoRelocs[j].ofstInRam < nanoRelocs[k].ofstInRam))
137                 k = j;
138         }
139         memcpy(&t, nanoRelocs + i, sizeof(struct NanoRelocEntry));
140         memcpy(nanoRelocs + i, nanoRelocs + k, sizeof(struct NanoRelocEntry));
141         memcpy(nanoRelocs + k, &t, sizeof(struct NanoRelocEntry));
142 
143         if (verbose)
144             fprintf(stderr, "SortedReloc[%3" PRIu32 "] = {0x%08" PRIX32 ",0x%02" PRIX8 "}\n", i, nanoRelocs[i].ofstInRam, nanoRelocs[i].type);
145     }
146 
147     //produce output nanorelocs in packed format
148     packedNanoRelocs = malloc(outNumRelocs * 6); //definitely big enough
149     packedNanoRelocSz = 0;
150     for (i = 0; i < outNumRelocs; i++) {
151         uint32_t displacement;
152 
153         if (lastOutType != nanoRelocs[i].type) {  //output type if ti changed
154             if (nanoRelocs[i].type - lastOutType == 1) {
155                 packedNanoRelocs[packedNanoRelocSz++] = TOKEN_RELOC_TYPE_NEXT;
156                 if (verbose)
157                     fprintf(stderr, "Out: RelocTC (1) // to 0x%02" PRIX8 "\n", nanoRelocs[i].type);
158             }
159             else {
160                 packedNanoRelocs[packedNanoRelocSz++] = TOKEN_RELOC_TYPE_CHG;
161                 packedNanoRelocs[packedNanoRelocSz++] = nanoRelocs[i].type - lastOutType - 1;
162                 if (verbose)
163                     fprintf(stderr, "Out: RelocTC (0x%02" PRIX8 ")  // to 0x%02" PRIX8 "\n", (uint8_t)(nanoRelocs[i].type - lastOutType - 1), nanoRelocs[i].type);
164             }
165             lastOutType = nanoRelocs[i].type;
166             origin = 0;
167         }
168         displacement = nanoRelocs[i].ofstInRam - origin;
169         origin = nanoRelocs[i].ofstInRam + 4;
170         if (displacement & 3) {
171             fprintf(stderr, "Unaligned relocs are not possible!\n");
172             exit(-5);
173         }
174         displacement /= 4;
175 
176         //might be start of a run. look into that
177         if (!displacement) {
178             for (j = 1; j + i < outNumRelocs && j < MAX_RUN_LEN && nanoRelocs[j + i].type == lastOutType && nanoRelocs[j + i].ofstInRam - nanoRelocs[j + i - 1].ofstInRam == 4; j++);
179             if (j >= MIN_RUN_LEN) {
180                 if (verbose)
181                     fprintf(stderr, "Out: Reloc0  x%" PRIX32 "\n", j);
182                 packedNanoRelocs[packedNanoRelocSz++] = TOKEN_CONSECUTIVE;
183                 packedNanoRelocs[packedNanoRelocSz++] = j - MIN_RUN_LEN;
184                 origin = nanoRelocs[j + i - 1].ofstInRam + 4;  //reset origin to last one
185                 i += j - 1;  //loop will increment anyways, hence +1
186                 continue;
187             }
188         }
189 
190         //produce output
191         if (displacement <= MAX_8_BIT_NUM) {
192             if (verbose)
193                 fprintf(stderr, "Out: Reloc8  0x%02" PRIX32 "\n", displacement);
194             packedNanoRelocs[packedNanoRelocSz++] = displacement;
195         }
196         else if (displacement <= MAX_16_BIT_NUM) {
197             if (verbose)
198                 fprintf(stderr, "Out: Reloc16 0x%06" PRIX32 "\n", displacement);
199                         displacement -= MAX_8_BIT_NUM;
200             packedNanoRelocs[packedNanoRelocSz++] = TOKEN_16BIT_OFST;
201             packedNanoRelocs[packedNanoRelocSz++] = displacement;
202             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 8;
203         }
204         else if (displacement <= MAX_24_BIT_NUM) {
205             if (verbose)
206                 fprintf(stderr, "Out: Reloc24 0x%08" PRIX32 "\n", displacement);
207                         displacement -= MAX_16_BIT_NUM;
208             packedNanoRelocs[packedNanoRelocSz++] = TOKEN_24BIT_OFST;
209             packedNanoRelocs[packedNanoRelocSz++] = displacement;
210             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 8;
211             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 16;
212         }
213         else  {
214             if (verbose)
215                 fprintf(stderr, "Out: Reloc32 0x%08" PRIX32 "\n", displacement);
216             packedNanoRelocs[packedNanoRelocSz++] = TOKEN_32BIT_OFST;
217             packedNanoRelocs[packedNanoRelocSz++] = displacement;
218             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 8;
219             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 16;
220             packedNanoRelocs[packedNanoRelocSz++] = displacement >> 24;
221         }
222     }
223 
224     *finalPackedNanoRelocSz = packedNanoRelocSz;
225     return packedNanoRelocs;
226 }
227 
finalizeAndWrite(uint8_t * buf,uint32_t bufUsed,uint32_t bufSz,FILE * out,uint32_t layoutFlags,uint64_t appId)228 static int finalizeAndWrite(uint8_t *buf, uint32_t bufUsed, uint32_t bufSz, FILE *out, uint32_t layoutFlags, uint64_t appId)
229 {
230     int ret;
231     struct AppInfo app;
232     struct SectInfo *sect;
233     struct BinHdr *bin = (struct BinHdr *) buf;
234     struct ImageHeader outHeader = {
235         .aosp = (struct nano_app_binary_t) {
236             .header_version = 1,
237             .magic = NANOAPP_AOSP_MAGIC,
238             .app_id = appId,
239             .app_version = bin->hdr.appVer,
240             .flags       = 0, // encrypted (1), signed (2) (will be set by other tools)
241         },
242         .layout = (struct ImageLayout) {
243             .magic = GOOGLE_LAYOUT_MAGIC,
244             .version = 1,
245             .payload = LAYOUT_APP,
246             .flags = layoutFlags,
247         },
248     };
249     uint32_t dataOffset = sizeof(outHeader) + sizeof(app);
250     uint32_t hdrDiff = dataOffset - sizeof(*bin);
251     app.sect = bin->sect;
252     app.vec  = bin->vec;
253 
254     assertMem(bufUsed + hdrDiff, bufSz);
255 
256     memmove(buf + dataOffset, buf + sizeof(*bin), bufUsed - sizeof(*bin));
257     bufUsed += hdrDiff;
258     memcpy(buf, &outHeader, sizeof(outHeader));
259     memcpy(buf + sizeof(outHeader), &app, sizeof(app));
260     sect = &app.sect;
261 
262     //if we have any bytes to output, show stats
263     if (bufUsed) {
264         uint32_t codeAndRoDataSz = sect->data_data;
265         uint32_t relocsSz = sect->rel_end - sect->rel_start;
266         uint32_t gotSz = sect->got_end - sect->data_start;
267         uint32_t bssSz = sect->bss_end - sect->bss_start;
268 
269         fprintf(stderr,"Final binary size %" PRIu32 " bytes\n", bufUsed);
270         fprintf(stderr, "\n");
271         fprintf(stderr, "       FW header size (flash):      %6zu bytes\n", FLASH_RELOC_OFFSET);
272         fprintf(stderr, "       Code + RO data (flash):      %6" PRIu32 " bytes\n", codeAndRoDataSz);
273         fprintf(stderr, "       Relocs (flash):              %6" PRIu32 " bytes\n", relocsSz);
274         fprintf(stderr, "       GOT + RW data (flash & RAM): %6" PRIu32 " bytes\n", gotSz);
275         fprintf(stderr, "       BSS (RAM):                   %6" PRIu32 " bytes\n", bssSz);
276         fprintf(stderr, "\n");
277         fprintf(stderr,"Runtime flash use: %" PRIu32 " bytes\n", (uint32_t)(codeAndRoDataSz + relocsSz + gotSz + FLASH_RELOC_OFFSET));
278         fprintf(stderr,"Runtime RAM use: %" PRIu32 " bytes\n", gotSz + bssSz);
279     }
280 
281     ret = fwrite(buf, bufUsed, 1, out) == 1 ? 0 : 2;
282     if (ret)
283         fprintf(stderr, "Failed to write output file: %s\n", strerror(errno));
284 
285     return ret;
286 }
287 
handleApp(uint8_t ** pbuf,uint32_t bufUsed,FILE * out,uint32_t layoutFlags,uint64_t appId,uint32_t appVer,bool verbose)288 static int handleApp(uint8_t **pbuf, uint32_t bufUsed, FILE *out, uint32_t layoutFlags, uint64_t appId, uint32_t appVer, bool verbose)
289 {
290     uint32_t i, numRelocs, numSyms, outNumRelocs = 0, packedNanoRelocSz;
291     struct NanoRelocEntry *nanoRelocs = NULL;
292     struct RelocEntry *relocs;
293     struct SymtabEntry *syms;
294     uint8_t *packedNanoRelocs;
295     uint32_t t;
296     struct BinHdr *bin;
297     int ret = -1;
298     struct SectInfo *sect;
299     uint8_t *buf = *pbuf;
300     uint32_t bufSz = bufUsed * 3 /2;
301 
302     //make buffer 50% bigger than bufUsed in case relocs grow out of hand
303     buf = reallocOrDie(buf, bufSz);
304     *pbuf = buf;
305 
306     //sanity checks
307     bin = (struct BinHdr*)buf;
308     if (bufUsed < sizeof(*bin)) {
309         fprintf(stderr, "File size too small\n");
310         goto out;
311     }
312 
313     if (bin->hdr.magic != NANOAPP_FW_MAGIC) {
314         fprintf(stderr, "Magic value is wrong: found %08" PRIX32
315                         "; expected %08" PRIX32 "\n",
316                         bin->hdr.magic, NANOAPP_FW_MAGIC);
317         goto out;
318     }
319 
320     sect = &bin->sect;
321     bin->hdr.appVer = appVer;
322 
323     //do some math
324     relocs = (struct RelocEntry*)(buf + sect->rel_start - FLASH_BASE);
325     syms = (struct SymtabEntry*)(buf + sect->rel_end - FLASH_BASE);
326     numRelocs = (sect->rel_end - sect->rel_start) / sizeof(struct RelocEntry);
327     numSyms = (bufUsed + FLASH_BASE - sect->rel_end) / sizeof(struct SymtabEntry);
328 
329     //sanity
330     if (numRelocs * sizeof(struct RelocEntry) + sect->rel_start != sect->rel_end) {
331         fprintf(stderr, "Relocs of nonstandard size\n");
332         goto out;
333     }
334     if (numSyms * sizeof(struct SymtabEntry) + sect->rel_end != bufUsed + FLASH_BASE) {
335         fprintf(stderr, "Syms of nonstandard size\n");
336         goto out;
337     }
338 
339     //show some info
340     fprintf(stderr, "\nRead %" PRIu32 " bytes of binary.\n", bufUsed);
341 
342     if (verbose)
343         fprintf(stderr, "Found %" PRIu32 " relocs and a %" PRIu32 "-entry symbol table\n", numRelocs, numSyms);
344 
345     //handle relocs
346     nanoRelocs = malloc(sizeof(struct NanoRelocEntry[numRelocs]));
347     if (!nanoRelocs) {
348         fprintf(stderr, "Failed to allocate a nano-reloc table\n");
349         goto out;
350     }
351 
352     for (i = 0; i < numRelocs; i++) {
353         uint32_t relocType = relocs[i].info & 0xff;
354         uint32_t whichSym = relocs[i].info >> 8;
355         uint32_t *valThereP;
356 
357         if (whichSym >= numSyms) {
358             fprintf(stderr, "Reloc %" PRIu32 " references a nonexistent symbol!\n"
359                             "INFO:\n"
360                             "        Where: 0x%08" PRIX32 "\n"
361                             "        type: %" PRIu32 "\n"
362                             "        sym: %" PRIu32 "\n",
363                 i, relocs[i].where, relocs[i].info & 0xff, whichSym);
364             goto out;
365         }
366 
367         if (verbose) {
368             const char *seg;
369 
370             fprintf(stderr, "Reloc[%3" PRIu32 "]:\n {@0x%08" PRIX32 ", type %3" PRIu32 ", -> sym[%3" PRIu32 "]: {@0x%08" PRIX32 "}, ",
371                 i, relocs[i].where, relocs[i].info & 0xff, whichSym, syms[whichSym].addr);
372 
373             if (IS_IN_RANGE_E(relocs[i].where, sect->bss_start, sect->bss_end))
374                 seg = ".bss";
375             else if (IS_IN_RANGE_E(relocs[i].where, sect->data_start, sect->data_end))
376                 seg = ".data";
377             else if (IS_IN_RANGE_E(relocs[i].where, sect->got_start, sect->got_end))
378                 seg = ".got";
379             else if (IS_IN_RANGE_E(relocs[i].where, FLASH_BASE, FLASH_BASE + sizeof(struct BinHdr)))
380                 seg = "APPHDR";
381             else
382                 seg = "???";
383 
384             fprintf(stderr, "in   %s}\n", seg);
385         }
386         /* handle relocs inside the header */
387         if (IS_IN_FLASH(relocs[i].where) && relocs[i].where - FLASH_BASE < sizeof(struct BinHdr) && relocType == RELOC_TYPE_SECT) {
388             /* relocs in header are special - runtime corrects for them */
389             if (syms[whichSym].addr) {
390                 fprintf(stderr, "Weird in-header sect reloc %" PRIu32 " to symbol %" PRIu32 " with nonzero addr 0x%08" PRIX32 "\n",
391                         i, whichSym, syms[whichSym].addr);
392                 goto out;
393             }
394 
395             valThereP = (uint32_t*)(buf + relocs[i].where - FLASH_BASE);
396             if (!IS_IN_FLASH(*valThereP)) {
397                 fprintf(stderr, "In-header reloc %" PRIu32 " of location 0x%08" PRIX32 " is outside of FLASH!\n"
398                                 "INFO:\n"
399                                 "        type: %" PRIu32 "\n"
400                                 "        sym: %" PRIu32 "\n"
401                                 "        Sym Addr: 0x%08" PRIX32 "\n",
402                                 i, relocs[i].where, relocType, whichSym, syms[whichSym].addr);
403                 goto out;
404             }
405 
406             // binary header generated by objcopy, .napp header and final FW header in flash are of different size.
407             // we subtract binary header offset here, so all the entry points are relative to beginning of "sect".
408             // FW will use &sect as a base to call these vectors; no more problems with different header sizes;
409             // Assumption: offsets between sect & vec, vec & code are the same in all images (or, in a simpler words, { sect, vec, code }
410             // must go together). this is enforced by linker script, and maintained by all tools and FW download code in the OS.
411             *valThereP -= FLASH_BASE + BINARY_RELOC_OFFSET;
412 
413             if (verbose)
414                 fprintf(stderr, "  -> Nano reloc skipped for in-header reloc\n");
415 
416             continue; /* do not produce an output reloc */
417         }
418 
419         if (!IS_IN_RAM(relocs[i].where)) {
420             fprintf(stderr, "In-header reloc %" PRIu32 " of location 0x%08" PRIX32 " is outside of RAM!\n"
421                             "INFO:\n"
422                             "        type: %" PRIu32 "\n"
423                             "        sym: %" PRIu32 "\n"
424                             "        Sym Addr: 0x%08" PRIX32 "\n",
425                             i, relocs[i].where, relocType, whichSym, syms[whichSym].addr);
426             goto out;
427         }
428 
429         valThereP = (uint32_t*)(buf + relocs[i].where + sect->data_data - RAM_BASE - FLASH_BASE);
430 
431         nanoRelocs[outNumRelocs].ofstInRam = relocs[i].where - RAM_BASE;
432 
433         switch (relocType) {
434             case RELOC_TYPE_ABS_S:
435             case RELOC_TYPE_ABS_D:
436                 t = *valThereP;
437 
438                 (*valThereP) += syms[whichSym].addr;
439 
440                 if (IS_IN_FLASH(syms[whichSym].addr)) {
441                     (*valThereP) -= FLASH_BASE + BINARY_RELOC_OFFSET;
442                     nanoRelocs[outNumRelocs].type = NANO_RELOC_TYPE_FLASH;
443                 }
444                 else if (IS_IN_RAM(syms[whichSym].addr)) {
445                     (*valThereP) -= RAM_BASE;
446                     nanoRelocs[outNumRelocs].type = NANO_RELOC_TYPE_RAM;
447                 }
448                 else {
449                     fprintf(stderr, "Weird reloc %" PRIu32 " to symbol %" PRIu32 " in unknown memory space (addr 0x%08" PRIX32 ")\n",
450                             i, whichSym, syms[whichSym].addr);
451                     goto out;
452                 }
453                 if (verbose)
454                     fprintf(stderr, "  -> Abs reference fixed up 0x%08" PRIX32 " -> 0x%08" PRIX32 "\n", t, *valThereP);
455                 break;
456 
457             case RELOC_TYPE_SECT:
458                 if (syms[whichSym].addr) {
459                     fprintf(stderr, "Weird sect reloc %" PRIu32 " to symbol %" PRIu32 " with nonzero addr 0x%08" PRIX32 "\n",
460                             i, whichSym, syms[whichSym].addr);
461                     goto out;
462                 }
463 
464                 t = *valThereP;
465 
466                 if (IS_IN_FLASH(*valThereP)) {
467                     nanoRelocs[outNumRelocs].type = NANO_RELOC_TYPE_FLASH;
468                     *valThereP -= FLASH_BASE + BINARY_RELOC_OFFSET;
469                 }
470                 else if (IS_IN_RAM(*valThereP)) {
471                     nanoRelocs[outNumRelocs].type = NANO_RELOC_TYPE_RAM;
472                     *valThereP -= RAM_BASE;
473                 }
474                 else {
475                     fprintf(stderr, "Weird sec reloc %" PRIu32 " to symbol %" PRIu32
476                                     " in unknown memory space (addr 0x%08" PRIX32 ")\n",
477                                     i, whichSym, *valThereP);
478                     goto out;
479                 }
480                 if (verbose)
481                     fprintf(stderr, "  -> Sect reference fixed up 0x%08" PRIX32 " -> 0x%08" PRIX32 "\n", t, *valThereP);
482                 break;
483 
484             default:
485                 fprintf(stderr, "Weird reloc %" PRIX32 " type %" PRIX32 " to symbol %" PRIX32 "\n", i, relocType, whichSym);
486                 goto out;
487         }
488 
489         if (verbose)
490             fprintf(stderr, "  -> Nano reloc calculated as 0x%08" PRIX32 ",0x%02" PRIX8 "\n", nanoRelocs[i].ofstInRam, nanoRelocs[i].type);
491         outNumRelocs++;
492     }
493 
494     packedNanoRelocs = packNanoRelocs(nanoRelocs, outNumRelocs, &packedNanoRelocSz, verbose);
495 
496     //overwrite original relocs and symtab with nanorelocs and adjust sizes
497     memcpy(relocs, packedNanoRelocs, packedNanoRelocSz);
498     bufUsed -= sizeof(struct RelocEntry[numRelocs]);
499     bufUsed -= sizeof(struct SymtabEntry[numSyms]);
500     bufUsed += packedNanoRelocSz;
501     assertMem(bufUsed, bufSz);
502     sect->rel_end = sect->rel_start + packedNanoRelocSz;
503 
504     //sanity
505     if (sect->rel_end - FLASH_BASE != bufUsed) {
506         fprintf(stderr, "Relocs end and file end not coincident\n");
507         goto out;
508     }
509 
510     //adjust headers for easy access (RAM)
511     if (!IS_IN_RAM(sect->data_start) || !IS_IN_RAM(sect->data_end) || !IS_IN_RAM(sect->bss_start) ||
512         !IS_IN_RAM(sect->bss_end) || !IS_IN_RAM(sect->got_start) || !IS_IN_RAM(sect->got_end)) {
513         fprintf(stderr, "data, bss, or got not in ram\n");
514         goto out;
515     }
516     sect->data_start -= RAM_BASE;
517     sect->data_end -= RAM_BASE;
518     sect->bss_start -= RAM_BASE;
519     sect->bss_end -= RAM_BASE;
520     sect->got_start -= RAM_BASE;
521     sect->got_end -= RAM_BASE;
522 
523     //adjust headers for easy access (FLASH)
524     if (!IS_IN_FLASH(sect->data_data) || !IS_IN_FLASH(sect->rel_start) || !IS_IN_FLASH(sect->rel_end)) {
525         fprintf(stderr, "data.data, or rel not in flash\n");
526         goto out;
527     }
528     sect->data_data -= FLASH_BASE + BINARY_RELOC_OFFSET;
529     sect->rel_start -= FLASH_BASE + BINARY_RELOC_OFFSET;
530     sect->rel_end -= FLASH_BASE + BINARY_RELOC_OFFSET;
531 
532     ret = finalizeAndWrite(buf, bufUsed, bufSz, out, layoutFlags, appId);
533 out:
534     free(nanoRelocs);
535     return ret;
536 }
537 
elfExtractSectionPointer(const Elf_Data * data,const char * name,struct ElfNanoApp * app)538 static void elfExtractSectionPointer(const Elf_Data *data, const char *name, struct ElfNanoApp *app)
539 {
540     // Maps section names to their byte offset in struct ElfNanoApp. Note that
541     // this assumes that the linker script puts text/code in the .flash section,
542     // RW data in .data, that relocs for .data are included in .rel.data, and
543     // the symbol table is emitted in .symtab
544     const struct SectionMap {
545         const char *name;
546         size_t offset;
547     } sectionMap[] = {
548         {
549             .name = ".flash",
550             .offset = offsetof(struct ElfNanoApp, flash),
551         },
552         {
553             .name = ".data",
554             .offset = offsetof(struct ElfNanoApp, data),
555         },
556         {
557             .name = ".rel.data",
558             .offset = offsetof(struct ElfNanoApp, relocs),
559         },
560         {
561             .name = ".symtab",
562             .offset = offsetof(struct ElfNanoApp, symtab),
563         },
564     };
565     struct ElfAppSection *appSection;
566     uint8_t *appBytes = (uint8_t *) app;
567 
568     for (size_t i = 0; i < ARRAY_SIZE(sectionMap); i++) {
569         if (strcmp(name, sectionMap[i].name) != 0) {
570             continue;
571         }
572         appSection = (struct ElfAppSection *) &appBytes[sectionMap[i].offset];
573 
574         appSection->data = data->d_buf;
575         appSection->size = data->d_size;
576 
577         DBG("Found section %s with size %zu", name, appSection->size);
578         break;
579     }
580 }
581 
582 // Populates a struct ElfNanoApp with data parsed from the ELF
elfParse(Elf * elf,struct ElfNanoApp * app)583 static bool elfParse(Elf *elf, struct ElfNanoApp *app)
584 {
585     size_t shdrstrndx;
586     Elf_Scn *scn = NULL;
587     GElf_Shdr shdr;
588     char *sectionName;
589     Elf_Data *elf_data;
590 
591     memset(app, 0, sizeof(*app));
592     if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
593         ELF_ERR("Couldn't get section name string table index");
594         return false;
595     }
596 
597     while ((scn = elf_nextscn(elf, scn)) != NULL) {
598         if (gelf_getshdr(scn, &shdr) != &shdr) {
599             ELF_ERR("Error getting section header");
600             return false;
601         }
602         sectionName = elf_strptr(elf, shdrstrndx, shdr.sh_name);
603 
604         elf_data = elf_getdata(scn, NULL);
605         if (!elf_data) {
606             ELF_ERR("Error getting data for section %s", sectionName);
607             return false;
608         }
609 
610         elfExtractSectionPointer(elf_data, sectionName, app);
611     }
612 
613     return true;
614 }
615 
loadNanoappElfFile(const char * fileName,struct ElfNanoApp * app)616 static bool loadNanoappElfFile(const char *fileName, struct ElfNanoApp *app)
617 {
618     int fd;
619     Elf *elf;
620 
621     if (elf_version(EV_CURRENT) == EV_NONE) {
622         ELF_ERR("Failed to initialize ELF library");
623         return false;
624     }
625 
626     fd = open(fileName, O_RDONLY, 0);
627     if (fd < 0) {
628         ERR("Failed to open file %s for reading: %s", fileName, strerror(errno));
629         return false;
630     }
631 
632     elf = elf_begin(fd, ELF_C_READ, NULL);
633     if (elf == NULL) {
634         ELF_ERR("Failed to open ELF");
635         return false;
636     }
637 
638     if (!elfParse(elf, app)) {
639         ERR("Failed to parse ELF file");
640         return false;
641     }
642 
643     return true;
644 }
645 
646 // Subtracts the fixed memory region offset from an absolute address and returns
647 // the associated NANO_RELOC_* value, or NANO_RELOC_LAST if the address is not
648 // in the expected range.
649 // Not strictly tied to ELF usage, but handled slightly differently.
fixupAddrElf(uint32_t * addr)650 static uint8_t fixupAddrElf(uint32_t *addr)
651 {
652     uint8_t type;
653 
654     // TODO: this assumes that the host running this tool has the same
655     // endianness as the image file/target processor
656     if (IS_IN_FLASH(*addr)) {
657         DBG("Fixup addr 0x%08" PRIX32 " (flash) --> 0x%08" PRIX32, *addr,
658             (uint32_t) (*addr - (FLASH_BASE + BINARY_RELOC_OFFSET)));
659         *addr -= FLASH_BASE + BINARY_RELOC_OFFSET;
660         type = NANO_RELOC_TYPE_FLASH;
661     } else if (IS_IN_RAM(*addr)) {
662         DBG("Fixup addr 0x%08" PRIX32 " (ram)   --> 0x%08" PRIX32, *addr,
663             *addr - RAM_BASE);
664         *addr -= RAM_BASE;
665         type = NANO_RELOC_TYPE_RAM;
666     } else {
667         DBG("Error: invalid address 0x%08" PRIX32, *addr);
668         type = NANO_RELOC_LAST;
669     }
670 
671     return type;
672 }
673 
674 // Fixup addresses in the header to be relative. Not strictly tied to the ELF
675 // format, but used only in that program flow in the current implementation.
fixupHeaderElf(const struct ElfNanoApp * app)676 static bool fixupHeaderElf(const struct ElfNanoApp *app)
677 {
678     struct BinHdr *hdr = (struct BinHdr *) app->flash.data;
679 
680     DBG("Appyling fixups to header");
681     if (fixupAddrElf(&hdr->sect.data_start) != NANO_RELOC_TYPE_RAM ||
682         fixupAddrElf(&hdr->sect.data_end)   != NANO_RELOC_TYPE_RAM ||
683         fixupAddrElf(&hdr->sect.bss_start)  != NANO_RELOC_TYPE_RAM ||
684         fixupAddrElf(&hdr->sect.bss_end)    != NANO_RELOC_TYPE_RAM ||
685         fixupAddrElf(&hdr->sect.got_start)  != NANO_RELOC_TYPE_RAM ||
686         fixupAddrElf(&hdr->sect.got_end)    != NANO_RELOC_TYPE_RAM) {
687         ERR(".data, .bss, or .got not in RAM address space!");
688         return false;
689     }
690 
691     if (fixupAddrElf(&hdr->sect.rel_start) != NANO_RELOC_TYPE_FLASH ||
692         fixupAddrElf(&hdr->sect.rel_end)   != NANO_RELOC_TYPE_FLASH ||
693         fixupAddrElf(&hdr->sect.data_data) != NANO_RELOC_TYPE_FLASH) {
694         ERR(".data loadaddr, or .relocs not in flash address space!");
695         return false;
696     }
697 
698     if (fixupAddrElf(&hdr->vec.init)   != NANO_RELOC_TYPE_FLASH ||
699         fixupAddrElf(&hdr->vec.end)    != NANO_RELOC_TYPE_FLASH ||
700         fixupAddrElf(&hdr->vec.handle) != NANO_RELOC_TYPE_FLASH) {
701         ERR("Entry point(s) not in flash address space!");
702         return false;
703     }
704 
705     return true;
706 }
707 
708 // Fixup addresses in .data, .init_array/.fini_array, and .got, and generates
709 // packed array of nano reloc entries. The app header must have already been
710 // fixed up.
genElfNanoRelocs(struct ElfNanoApp * app,bool verbose)711 static bool genElfNanoRelocs(struct ElfNanoApp *app, bool verbose)
712 {
713     const struct BinHdr *hdr = (const struct BinHdr *) app->flash.data;
714     const struct SectInfo *sect = &hdr->sect;
715     bool success = false;
716 
717     size_t numDataRelocs = app->relocs.size / sizeof(Elf32_Rel);
718     size_t gotCount = (sect->got_end - sect->got_start) / sizeof(uint32_t);
719     size_t numInitFuncs  = (sect->bss_start - sect->data_end) / sizeof(uint32_t);
720 
721     size_t totalRelocCount = (numDataRelocs + numInitFuncs + gotCount);
722     struct NanoRelocEntry *nanoRelocs = malloc(
723         totalRelocCount * sizeof(struct NanoRelocEntry));
724     if (!nanoRelocs) {
725         ERR("Couldn't allocate memory for nano relocs! Needed %zu bytes",
726             totalRelocCount * sizeof(struct NanoRelocEntry));
727         return false;
728     }
729 
730     uint8_t *data = app->data.data;
731     const Elf32_Rel *relocs = (const Elf32_Rel *) app->relocs.data;
732     const Elf32_Sym *syms   = (const Elf32_Sym *) app->symtab.data;
733     size_t numRelocs = 0;
734 
735     DBG("Parsing relocs for .data (%zu):", numDataRelocs);
736     for (size_t i = 0; i < numDataRelocs; i++) {
737         uint32_t type = ELF32_R_TYPE(relocs[i].r_info);
738         uint32_t sym = ELF32_R_SYM(relocs[i].r_info);
739 
740         DBG(" [%3zu] 0x%08" PRIx32 " type %2" PRIu32 " symIdx %3" PRIu32
741             " --> 0x%08" PRIx32, i, relocs[i].r_offset, type, sym,
742             syms[sym].st_value);
743         // Note that R_ARM_TARGET1 is used for .init_array/.fini_array support,
744         // and can be interpreted either as ABS32 or REL32, depending on the
745         // runtime; we expect it to be ABS32.
746         if (type == R_ARM_ABS32 || type == R_ARM_TARGET1) {
747             if (!IS_IN_RAM(relocs[i].r_offset)) {
748                 ERR("Reloc for .data not in RAM address range!");
749                 goto out;
750             }
751             uint32_t offset = relocs[i].r_offset - RAM_BASE;
752             uint32_t *addr = (uint32_t *) &data[offset];
753 
754             nanoRelocs[numRelocs].type = fixupAddrElf(addr);
755             nanoRelocs[numRelocs].ofstInRam = offset;
756             numRelocs++;
757         } else {
758             // TODO: Assuming that the ELF only contains absolute addresses in
759             // the .data section; may need to handle other relocation types in
760             // the future
761             ERR("Error: Unexpected reloc type %" PRIu32 " at index %zu",
762                 type, i);
763             goto out;
764         }
765     }
766 
767     DBG("Updating GOT entries (%zu):", gotCount);
768     for (uint32_t offset = sect->got_start; offset < sect->got_end;
769             offset += sizeof(uint32_t)) {
770         uint32_t *addr = (uint32_t *) &data[offset];
771         // Skip values that are set to 0, these seem to be padding (?)
772         if (*addr) {
773             nanoRelocs[numRelocs].type = fixupAddrElf(addr);
774             nanoRelocs[numRelocs].ofstInRam = offset;
775             numRelocs++;
776         }
777     }
778 
779     uint32_t packedNanoRelocSz = 0;
780     app->packedNanoRelocs.data = packNanoRelocs(
781         nanoRelocs, numRelocs, &packedNanoRelocSz, verbose);
782     app->packedNanoRelocs.size = packedNanoRelocSz;
783     success = true;
784 out:
785     free(nanoRelocs);
786     return success;
787 }
788 
handleAppStatic(const char * fileName,FILE * out,uint32_t layoutFlags,uint64_t appId,uint32_t appVer,bool verbose)789 static int handleAppStatic(const char *fileName, FILE *out, uint32_t layoutFlags, uint64_t appId, uint32_t appVer, bool verbose)
790 {
791     struct ElfNanoApp app;
792 
793     if (!loadNanoappElfFile(fileName, &app)
794             || !fixupHeaderElf(&app)
795             || !genElfNanoRelocs(&app, verbose)) {
796         exit(2);
797     }
798 
799     // Construct a single contiguous buffer, with extra room to fit the
800     // ImageHeader that will be prepended by finalizeAndWrite(). Note that this
801     // will allocate a bit more space than is needed, because some of the data
802     // from BinHdr will get discarded.
803     // TODO: this should be refactored to just write the binary components in
804     // order rather than allocating a big buffer, and moving data around
805     size_t bufSize = app.flash.size + app.data.size + app.packedNanoRelocs.size
806         + sizeof(struct ImageHeader);
807     uint8_t *buf = malloc(bufSize);
808     if (!buf) {
809         ERR("Failed to allocate %zu bytes for final app", bufSize);
810         exit(2);
811     }
812 
813     size_t offset = 0;
814     memcpy(buf, app.flash.data, app.flash.size);
815     offset += app.flash.size;
816     memcpy(&buf[offset], app.data.data, app.data.size);
817     offset += app.data.size;
818     memcpy(&buf[offset], app.packedNanoRelocs.data, app.packedNanoRelocs.size);
819     offset += app.packedNanoRelocs.size;
820 
821     // Update rel_end in the header to reflect the packed reloc size
822     struct BinHdr *hdr = (struct BinHdr *) buf;
823     hdr->sect.rel_end = hdr->sect.rel_start + app.packedNanoRelocs.size;
824     hdr->hdr.appVer = appVer;
825 
826     return finalizeAndWrite(buf, offset, bufSize, out, layoutFlags, appId);
827     // TODO: should free all memory we allocated... just letting the OS handle
828     // it for now
829 }
830 
handleKey(uint8_t ** pbuf,uint32_t bufUsed,FILE * out,uint32_t layoutFlags,uint64_t appId,uint64_t keyId)831 static int handleKey(uint8_t **pbuf, uint32_t bufUsed, FILE *out, uint32_t layoutFlags, uint64_t appId, uint64_t keyId)
832 {
833     uint8_t *buf = *pbuf;
834     struct KeyInfo ki = { .data = keyId };
835     bool good = true;
836 
837     struct ImageHeader outHeader = {
838         .aosp = (struct nano_app_binary_t) {
839             .header_version = 1,
840             .magic = NANOAPP_AOSP_MAGIC,
841             .app_id = appId,
842         },
843         .layout = (struct ImageLayout) {
844             .magic = GOOGLE_LAYOUT_MAGIC,
845             .version = 1,
846             .payload = LAYOUT_KEY,
847             .flags = layoutFlags,
848         },
849     };
850 
851     good = good && fwrite(&outHeader, sizeof(outHeader), 1, out) == 1;
852     good = good && fwrite(&ki, sizeof(ki), 1, out) ==  1;
853     good = good && fwrite(buf, bufUsed, 1, out) == 1;
854 
855     return good ? 0 : 2;
856 }
857 
handleOs(uint8_t ** pbuf,uint32_t bufUsed,FILE * out,uint32_t layoutFlags,bool bare)858 static int handleOs(uint8_t **pbuf, uint32_t bufUsed, FILE *out, uint32_t layoutFlags, bool bare)
859 {
860     uint8_t *buf = *pbuf;
861     bool good;
862 
863     struct OsUpdateHdr os = {
864         .magic = OS_UPDT_MAGIC,
865         .marker = OS_UPDT_MARKER_INPROGRESS,
866         .size = bufUsed
867     };
868 
869     struct ImageHeader outHeader = {
870         .aosp = (struct nano_app_binary_t) {
871             .header_version = 1,
872             .magic = NANOAPP_AOSP_MAGIC,
873         },
874         .layout = (struct ImageLayout) {
875             .magic = GOOGLE_LAYOUT_MAGIC,
876             .version = 1,
877             .payload = LAYOUT_OS,
878             .flags = layoutFlags,
879         },
880     };
881 
882     if (!bare)
883         good = fwrite(&outHeader, sizeof(outHeader), 1, out) == 1;
884     else
885         good = fwrite(&os, sizeof(os), 1, out) == 1;
886     good = good && fwrite(buf, bufUsed, 1, out) == 1;
887 
888     return good ? 0 : 2;
889 }
890 
main(int argc,char ** argv)891 int main(int argc, char **argv)
892 {
893     uint32_t bufUsed = 0;
894     bool verbose = false;
895     uint8_t *buf = NULL;
896     uint64_t appId = 0;
897     uint64_t keyId = 0;
898     uint32_t appVer = 0;
899     uint32_t layoutId = 0;
900     uint32_t layoutFlags = 0;
901     int ret = -1;
902     uint32_t *u32Arg = NULL;
903     uint64_t *u64Arg = NULL;
904     const char **strArg = NULL;
905     const char *appName = argv[0];
906     int posArgCnt = 0;
907     const char *posArg[2] = { NULL };
908     FILE *out = NULL;
909     const char *layoutName = "app";
910     const char *prev = NULL;
911     bool bareData = false;
912     bool staticElf = false;
913 
914     for (int i = 1; i < argc; i++) {
915         char *end = NULL;
916         if (argv[i][0] == '-') {
917             prev = argv[i];
918             if (!strcmp(argv[i], "-v"))
919                 verbose = true;
920             else if (!strcmp(argv[i], "-r"))
921                 bareData = true;
922             else if (!strcmp(argv[i], "-s"))
923                 staticElf = true;
924             else if (!strcmp(argv[i], "-a"))
925                 u64Arg = &appId;
926             else if (!strcmp(argv[i], "-e"))
927                 u32Arg = &appVer;
928             else if (!strcmp(argv[i], "-k"))
929                 u64Arg = &keyId;
930             else if (!strcmp(argv[i], "-n"))
931                 strArg = &layoutName;
932             else if (!strcmp(argv[i], "-i"))
933                 u32Arg = &layoutId;
934             else if (!strcmp(argv[i], "-f"))
935                 u32Arg = &layoutFlags;
936             else
937                 fatalUsage(appName, "unknown argument", argv[i]);
938         } else {
939             if (u64Arg) {
940                 uint64_t tmp = strtoull(argv[i], &end, 16);
941                 if (*end == '\0')
942                     *u64Arg = tmp;
943                 u64Arg = NULL;
944             } else if (u32Arg) {
945                 uint32_t tmp = strtoul(argv[i], &end, 16);
946                 if (*end == '\0')
947                     *u32Arg = tmp;
948                 u32Arg = NULL;
949             } else if (strArg) {
950                     *strArg = argv[i];
951                 strArg = NULL;
952             } else {
953                 if (posArgCnt < 2)
954                     posArg[posArgCnt++] = argv[i];
955                 else
956                     fatalUsage(appName, "too many positional arguments", argv[i]);
957             }
958             prev = NULL;
959         }
960     }
961     if (prev)
962         fatalUsage(appName, "missing argument after", prev);
963 
964     if (!posArgCnt)
965         fatalUsage(appName, "missing input file name", NULL);
966 
967     if (!layoutId) {
968         if (strcmp(layoutName, "app") == 0)
969             layoutId = LAYOUT_APP;
970         else if (strcmp(layoutName, "os") == 0)
971             layoutId = LAYOUT_OS;
972         else if (strcmp(layoutName, "key") == 0)
973             layoutId = LAYOUT_KEY;
974         else
975             fatalUsage(appName, "Invalid layout name", layoutName);
976     }
977 
978     if (staticElf && layoutId != LAYOUT_APP)
979         fatalUsage(appName, "Only app layout is supported for static option", NULL);
980 
981     if (layoutId == LAYOUT_APP && !appId)
982         fatalUsage(appName, "App layout requires app ID", NULL);
983     if (layoutId == LAYOUT_KEY && !keyId)
984         fatalUsage(appName, "Key layout requires key ID", NULL);
985     if (layoutId == LAYOUT_OS && (keyId || appId))
986         fatalUsage(appName, "OS layout does not need any ID", NULL);
987 
988     if (!staticElf) {
989         buf = loadFile(posArg[0], &bufUsed);
990         fprintf(stderr, "Read %" PRIu32 " bytes\n", bufUsed);
991     }
992 
993     if (!posArg[1])
994         out = stdout;
995     else
996         out = fopen(posArg[1], "w");
997     if (!out)
998         fatalUsage(appName, "failed to create/open output file", posArg[1]);
999 
1000     switch(layoutId) {
1001     case LAYOUT_APP:
1002         if (staticElf) {
1003             ret = handleAppStatic(posArg[0], out, layoutFlags, appId, appVer, verbose);
1004         } else {
1005             ret = handleApp(&buf, bufUsed, out, layoutFlags, appId, appVer, verbose);
1006         }
1007         break;
1008     case LAYOUT_KEY:
1009         ret = handleKey(&buf, bufUsed, out, layoutFlags, appId, keyId);
1010         break;
1011     case LAYOUT_OS:
1012         ret = handleOs(&buf, bufUsed, out, layoutFlags, bareData);
1013         break;
1014     }
1015 
1016     free(buf);
1017     fclose(out);
1018     return ret;
1019 }
1020