1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5
6 #include <subcmd/parse-options.h>
7 #include <string.h>
8 #include <stdlib.h>
9 #include <fcntl.h>
10 #include <unistd.h>
11 #include <errno.h>
12 #include <sys/stat.h>
13 #include <sys/sendfile.h>
14 #include <objtool/builtin.h>
15 #include <objtool/objtool.h>
16 #include <objtool/warn.h>
17
18 #define ORIG_SUFFIX ".orig"
19
20 int orig_argc;
21 static char **orig_argv;
22 const char *objname;
23 struct opts opts;
24
25 static const char * const check_usage[] = {
26 "objtool <actions> [<options>] file.o",
27 NULL,
28 };
29
30 static const char * const env_usage[] = {
31 "OBJTOOL_ARGS=\"<options>\"",
32 NULL,
33 };
34
parse_dump(const struct option * opt,const char * str,int unset)35 static int parse_dump(const struct option *opt, const char *str, int unset)
36 {
37 if (!str || !strcmp(str, "orc")) {
38 opts.dump_orc = true;
39 return 0;
40 }
41
42 return -1;
43 }
44
parse_hacks(const struct option * opt,const char * str,int unset)45 static int parse_hacks(const struct option *opt, const char *str, int unset)
46 {
47 bool found = false;
48
49 /*
50 * Use strstr() as a lazy method of checking for comma-separated
51 * options.
52 *
53 * No string provided == enable all options.
54 */
55
56 if (!str || strstr(str, "jump_label")) {
57 opts.hack_jump_label = true;
58 found = true;
59 }
60
61 if (!str || strstr(str, "noinstr")) {
62 opts.hack_noinstr = true;
63 found = true;
64 }
65
66 if (!str || strstr(str, "skylake")) {
67 opts.hack_skylake = true;
68 found = true;
69 }
70
71 return found ? 0 : -1;
72 }
73
74 static const struct option check_options[] = {
75 OPT_GROUP("Actions:"),
76 OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
77 OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
78 OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
79 OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
80 OPT_BOOLEAN(0, "orc", &opts.orc, "generate ORC metadata"),
81 OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
82 OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
83 OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"),
84 OPT_INTEGER(0, "prefix", &opts.prefix, "generate prefix symbols"),
85 OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
86 OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
87 OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
88 OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
89 OPT_BOOLEAN(0 , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
90 OPT_BOOLEAN(0 , "noabs", &opts.noabs, "reject absolute references in allocatable sections"),
91 OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
92
93 OPT_GROUP("Options:"),
94 OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
95 OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
96 OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
97 OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
98 OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
99 OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
100 OPT_STRING('o', "output", &opts.output, "file", "output file name"),
101 OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
102 OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
103 OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
104 OPT_BOOLEAN(0, "Werror", &opts.werror, "return error on warnings"),
105
106 OPT_END(),
107 };
108
cmd_parse_options(int argc,const char ** argv,const char * const usage[])109 int cmd_parse_options(int argc, const char **argv, const char * const usage[])
110 {
111 const char *envv[16] = { };
112 char *env;
113 int envc;
114
115 env = getenv("OBJTOOL_ARGS");
116 if (env) {
117 envv[0] = "OBJTOOL_ARGS";
118 for (envc = 1; envc < ARRAY_SIZE(envv); ) {
119 envv[envc++] = env;
120 env = strchr(env, ' ');
121 if (!env)
122 break;
123 *env = '\0';
124 env++;
125 }
126
127 parse_options(envc, envv, check_options, env_usage, 0);
128 }
129
130 env = getenv("OBJTOOL_VERBOSE");
131 if (env && !strcmp(env, "1"))
132 opts.verbose = true;
133
134 argc = parse_options(argc, argv, check_options, usage, 0);
135 if (argc != 1)
136 usage_with_options(usage, check_options);
137 return argc;
138 }
139
opts_valid(void)140 static bool opts_valid(void)
141 {
142 if (opts.mnop && !opts.mcount) {
143 ERROR("--mnop requires --mcount");
144 return false;
145 }
146
147 if (opts.noinstr && !opts.link) {
148 ERROR("--noinstr requires --link");
149 return false;
150 }
151
152 if (opts.ibt && !opts.link) {
153 ERROR("--ibt requires --link");
154 return false;
155 }
156
157 if (opts.unret && !opts.link) {
158 ERROR("--unret requires --link");
159 return false;
160 }
161
162 if (opts.hack_jump_label ||
163 opts.hack_noinstr ||
164 opts.ibt ||
165 opts.mcount ||
166 opts.noabs ||
167 opts.noinstr ||
168 opts.orc ||
169 opts.retpoline ||
170 opts.rethunk ||
171 opts.sls ||
172 opts.stackval ||
173 opts.static_call ||
174 opts.uaccess) {
175 if (opts.dump_orc) {
176 ERROR("--dump can't be combined with other actions");
177 return false;
178 }
179
180 return true;
181 }
182
183 if (opts.dump_orc)
184 return true;
185
186 ERROR("At least one action required");
187 return false;
188 }
189
copy_file(const char * src,const char * dst)190 static int copy_file(const char *src, const char *dst)
191 {
192 size_t to_copy, copied;
193 int dst_fd, src_fd;
194 struct stat stat;
195 off_t offset = 0;
196
197 src_fd = open(src, O_RDONLY);
198 if (src_fd == -1) {
199 ERROR("can't open %s for reading: %s", src, strerror(errno));
200 return 1;
201 }
202
203 dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400);
204 if (dst_fd == -1) {
205 ERROR("can't open %s for writing: %s", dst, strerror(errno));
206 return 1;
207 }
208
209 if (fstat(src_fd, &stat) == -1) {
210 ERROR_GLIBC("fstat");
211 return 1;
212 }
213
214 if (fchmod(dst_fd, stat.st_mode) == -1) {
215 ERROR_GLIBC("fchmod");
216 return 1;
217 }
218
219 for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) {
220 copied = sendfile(dst_fd, src_fd, &offset, to_copy);
221 if (copied == -1) {
222 ERROR_GLIBC("sendfile");
223 return 1;
224 }
225 }
226
227 close(dst_fd);
228 close(src_fd);
229 return 0;
230 }
231
save_argv(int argc,const char ** argv)232 static void save_argv(int argc, const char **argv)
233 {
234 orig_argv = calloc(argc, sizeof(char *));
235 if (!orig_argv) {
236 ERROR_GLIBC("calloc");
237 exit(1);
238 }
239
240 for (int i = 0; i < argc; i++) {
241 orig_argv[i] = strdup(argv[i]);
242 if (!orig_argv[i]) {
243 ERROR_GLIBC("strdup(%s)", argv[i]);
244 exit(1);
245 }
246 };
247 }
248
print_args(void)249 void print_args(void)
250 {
251 char *backup = NULL;
252
253 if (opts.output || opts.dryrun)
254 goto print;
255
256 /*
257 * Make a backup before kbuild deletes the file so the error
258 * can be recreated without recompiling or relinking.
259 */
260 backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
261 if (!backup) {
262 ERROR_GLIBC("malloc");
263 goto print;
264 }
265
266 strcpy(backup, objname);
267 strcat(backup, ORIG_SUFFIX);
268 if (copy_file(objname, backup)) {
269 backup = NULL;
270 goto print;
271 }
272
273 print:
274 /*
275 * Print the cmdline args to make it easier to recreate. If '--output'
276 * wasn't used, add it to the printed args with the backup as input.
277 */
278 fprintf(stderr, "%s", orig_argv[0]);
279
280 for (int i = 1; i < orig_argc; i++) {
281 char *arg = orig_argv[i];
282
283 if (backup && !strcmp(arg, objname))
284 fprintf(stderr, " %s -o %s", backup, objname);
285 else
286 fprintf(stderr, " %s", arg);
287 }
288
289 fprintf(stderr, "\n");
290 }
291
objtool_run(int argc,const char ** argv)292 int objtool_run(int argc, const char **argv)
293 {
294 struct objtool_file *file;
295 int ret = 0;
296
297 orig_argc = argc;
298 save_argv(argc, argv);
299
300 cmd_parse_options(argc, argv, check_usage);
301
302 if (!opts_valid())
303 return 1;
304
305 objname = argv[0];
306
307 if (opts.dump_orc)
308 return orc_dump(objname);
309
310 if (!opts.dryrun && opts.output) {
311 /* copy original .o file to output file */
312 if (copy_file(objname, opts.output))
313 return 1;
314
315 /* from here on, work directly on the output file */
316 objname = opts.output;
317 }
318
319 file = objtool_open_read(objname);
320 if (!file)
321 return 1;
322
323 if (!opts.link && has_multiple_files(file->elf)) {
324 ERROR("Linked object requires --link");
325 return 1;
326 }
327
328 ret = check(file);
329 if (ret)
330 return ret;
331
332 if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
333 return 1;
334
335 return 0;
336 }
337