1 /*
2 * Copyright (c) 2013 Google, Inc.
3 *
4 * Use of this source code is governed by a MIT-style
5 * license that can be found in the LICENSE file or at
6 * https://opensource.org/licenses/MIT
7 */
8 #include <lib/buildsig.h>
9
10 #include <lk/debug.h>
11 #include <lk/err.h>
12 #include <stdint.h>
13 #include <stdio.h>
14 #include <string.h>
15 #include <lk/compiler.h>
16 #include <lib/version.h>
17 #include <lk/console_cmd.h>
18
19 #define MAGIC ((uint32_t)'BSIG')
20 #define MAGIC2 (~MAGIC)
21 #define MAGIC3 ((uint32_t)'BSG2')
22
23 struct buildsig {
24 uint32_t magic;
25
26 const lk_version_t *version;
27
28 uint32_t magic2;
29
30 uint32_t buildtype;
31 uint32_t start;
32 uint32_t end;
33 uint32_t crc32;
34
35 uint32_t magic3;
36 };
37
38 extern char __rom_start;
39 extern char __rom_end;
40
41 const struct buildsig buildsig __SECTION(".text.boot") = {
42 .magic = MAGIC,
43 .version = &lk_version,
44 .magic2 = MAGIC2,
45 #if WITH_APP_BOOTLOADER
46 .buildtype = 1, /* TODO: pull from systemwide headers */
47 #else
48 .buildtype = 0,
49 #endif
50 .start = (uint32_t) &__rom_start,
51 .end = (uint32_t) &__rom_end,
52 .crc32 = 0, /* filled in via an external tool */
53 .magic3 = MAGIC3
54 };
55
buildsig_search(const void * _ptr,size_t search_len,size_t max_len,const lk_version_t ** version)56 status_t buildsig_search(const void *_ptr, size_t search_len, size_t max_len, const lk_version_t **version) {
57 if (max_len < search_len)
58 return ERR_INVALID_ARGS;
59
60 if (max_len < sizeof(lk_version_t))
61 return ERR_INVALID_ARGS;
62
63 /* search for the build signature on 4 byte boundaries */
64 const uint32_t *ptr = _ptr;
65 for (size_t pos = 0; pos < search_len / 4; pos++) {
66 const struct buildsig *sig = (void *)&ptr[pos];
67
68 /* see if the buildsig's magic matches */
69 if (sig->magic != MAGIC || sig->magic2 != MAGIC2)
70 continue;
71
72 /* make sure the pointer to the version struct makes sense */
73 if ((size_t)sig->version - (size_t)ptr > max_len - sizeof(lk_version_t))
74 continue;
75
76 /* validate the strings in the version struct make sense */
77 /* ensure they lie within the search area (ptr .. ptr+max_len) */
78 #define VALIDSTR(str) \
79 (((size_t)(str) >= (size_t)ptr) && (((size_t)(str) - (size_t)ptr) < max_len))
80 if (!VALIDSTR(sig->version->arch))
81 continue;
82 if (!VALIDSTR(sig->version->platform))
83 continue;
84 if (!VALIDSTR(sig->version->target))
85 continue;
86 if (!VALIDSTR(sig->version->project))
87 continue;
88 if (!VALIDSTR(sig->version->buildid))
89 continue;
90 #undef VALIDSTR
91
92 *version = sig->version;
93 return NO_ERROR;
94 }
95
96 return ERR_NOT_FOUND;
97 }
98
99 extern char __rom_start;
100
cmd_buildsig(int argc,const console_cmd_args * argv)101 static int cmd_buildsig(int argc, const console_cmd_args *argv) {
102 if (argc < 2) {
103 //notenoughargs:
104 printf("not enough args\n");
105 usage:
106 printf("usage: %s dump [offset]\n", argv[0].str);
107 return -1;
108 }
109
110 if (!strcmp(argv[1].str, "dump")) {
111 const void *offset = &__rom_start;
112 if (argc >= 3) {
113 offset = argv[2].p;
114 }
115
116 const lk_version_t *v;
117 status_t err = buildsig_search(offset, DEFAULT_BUILDSIG_SEARCH_LEN, 256*1024, &v);
118 if (err < 0) {
119 printf("could not find build signature\n");
120 return ERR_NOT_FOUND;
121 }
122
123 printf("found signature:\n");
124 printf("\tarch: %s\n\tplatform: %s\n\ttarget: %s\n\tproject: %s\n\tbuildid: %s\n",
125 v->arch, v->platform, v->target, v->project, v->buildid);
126 } else {
127 goto usage;
128 }
129
130 return NO_ERROR;
131 }
132
133
134 STATIC_COMMAND_START
135 #if LK_DEBUGLEVEL > 1
136 STATIC_COMMAND("buildsig", "scan for and dump build signature", &cmd_buildsig)
137 #endif
138 STATIC_COMMAND_END(buildid);
139
140