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 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 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_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump), 91 92 OPT_GROUP("Options:"), 93 OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"), 94 OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"), 95 OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"), 96 OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"), 97 OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"), 98 OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"), 99 OPT_STRING('o', "output", &opts.output, "file", "output file name"), 100 OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"), 101 OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"), 102 OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"), 103 OPT_BOOLEAN(0, "Werror", &opts.werror, "return error on warnings"), 104 105 OPT_END(), 106 }; 107 108 int cmd_parse_options(int argc, const char **argv, const char * const usage[]) 109 { 110 const char *envv[16] = { }; 111 char *env; 112 int envc; 113 114 env = getenv("OBJTOOL_ARGS"); 115 if (env) { 116 envv[0] = "OBJTOOL_ARGS"; 117 for (envc = 1; envc < ARRAY_SIZE(envv); ) { 118 envv[envc++] = env; 119 env = strchr(env, ' '); 120 if (!env) 121 break; 122 *env = '\0'; 123 env++; 124 } 125 126 parse_options(envc, envv, check_options, env_usage, 0); 127 } 128 129 env = getenv("OBJTOOL_VERBOSE"); 130 if (env && !strcmp(env, "1")) 131 opts.verbose = true; 132 133 argc = parse_options(argc, argv, check_options, usage, 0); 134 if (argc != 1) 135 usage_with_options(usage, check_options); 136 return argc; 137 } 138 139 static bool opts_valid(void) 140 { 141 if (opts.mnop && !opts.mcount) { 142 ERROR("--mnop requires --mcount"); 143 return false; 144 } 145 146 if (opts.noinstr && !opts.link) { 147 ERROR("--noinstr requires --link"); 148 return false; 149 } 150 151 if (opts.ibt && !opts.link) { 152 ERROR("--ibt requires --link"); 153 return false; 154 } 155 156 if (opts.unret && !opts.link) { 157 ERROR("--unret requires --link"); 158 return false; 159 } 160 161 if (opts.hack_jump_label || 162 opts.hack_noinstr || 163 opts.ibt || 164 opts.mcount || 165 opts.noinstr || 166 opts.orc || 167 opts.retpoline || 168 opts.rethunk || 169 opts.sls || 170 opts.stackval || 171 opts.static_call || 172 opts.uaccess) { 173 if (opts.dump_orc) { 174 ERROR("--dump can't be combined with other actions"); 175 return false; 176 } 177 178 return true; 179 } 180 181 if (opts.dump_orc) 182 return true; 183 184 ERROR("At least one action required"); 185 return false; 186 } 187 188 static int copy_file(const char *src, const char *dst) 189 { 190 size_t to_copy, copied; 191 int dst_fd, src_fd; 192 struct stat stat; 193 off_t offset = 0; 194 195 src_fd = open(src, O_RDONLY); 196 if (src_fd == -1) { 197 ERROR("can't open %s for reading: %s", src, strerror(errno)); 198 return 1; 199 } 200 201 dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400); 202 if (dst_fd == -1) { 203 ERROR("can't open %s for writing: %s", dst, strerror(errno)); 204 return 1; 205 } 206 207 if (fstat(src_fd, &stat) == -1) { 208 ERROR_GLIBC("fstat"); 209 return 1; 210 } 211 212 if (fchmod(dst_fd, stat.st_mode) == -1) { 213 ERROR_GLIBC("fchmod"); 214 return 1; 215 } 216 217 for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) { 218 copied = sendfile(dst_fd, src_fd, &offset, to_copy); 219 if (copied == -1) { 220 ERROR_GLIBC("sendfile"); 221 return 1; 222 } 223 } 224 225 close(dst_fd); 226 close(src_fd); 227 return 0; 228 } 229 230 static void save_argv(int argc, const char **argv) 231 { 232 orig_argv = calloc(argc, sizeof(char *)); 233 if (!orig_argv) { 234 ERROR_GLIBC("calloc"); 235 exit(1); 236 } 237 238 for (int i = 0; i < argc; i++) { 239 orig_argv[i] = strdup(argv[i]); 240 if (!orig_argv[i]) { 241 ERROR_GLIBC("strdup(%s)", argv[i]); 242 exit(1); 243 } 244 }; 245 } 246 247 void print_args(void) 248 { 249 char *backup = NULL; 250 251 if (opts.output || opts.dryrun) 252 goto print; 253 254 /* 255 * Make a backup before kbuild deletes the file so the error 256 * can be recreated without recompiling or relinking. 257 */ 258 backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1); 259 if (!backup) { 260 ERROR_GLIBC("malloc"); 261 goto print; 262 } 263 264 strcpy(backup, objname); 265 strcat(backup, ORIG_SUFFIX); 266 if (copy_file(objname, backup)) { 267 backup = NULL; 268 goto print; 269 } 270 271 print: 272 /* 273 * Print the cmdline args to make it easier to recreate. If '--output' 274 * wasn't used, add it to the printed args with the backup as input. 275 */ 276 fprintf(stderr, "%s", orig_argv[0]); 277 278 for (int i = 1; i < orig_argc; i++) { 279 char *arg = orig_argv[i]; 280 281 if (backup && !strcmp(arg, objname)) 282 fprintf(stderr, " %s -o %s", backup, objname); 283 else 284 fprintf(stderr, " %s", arg); 285 } 286 287 fprintf(stderr, "\n"); 288 } 289 290 int objtool_run(int argc, const char **argv) 291 { 292 struct objtool_file *file; 293 int ret = 0; 294 295 orig_argc = argc; 296 save_argv(argc, argv); 297 298 cmd_parse_options(argc, argv, check_usage); 299 300 if (!opts_valid()) 301 return 1; 302 303 objname = argv[0]; 304 305 if (opts.dump_orc) 306 return orc_dump(objname); 307 308 if (!opts.dryrun && opts.output) { 309 /* copy original .o file to output file */ 310 if (copy_file(objname, opts.output)) 311 return 1; 312 313 /* from here on, work directly on the output file */ 314 objname = opts.output; 315 } 316 317 file = objtool_open_read(objname); 318 if (!file) 319 return 1; 320 321 if (!opts.link && has_multiple_files(file->elf)) { 322 ERROR("Linked object requires --link"); 323 return 1; 324 } 325 326 ret = check(file); 327 if (ret) 328 return ret; 329 330 if (!opts.dryrun && file->elf->changed && elf_write(file->elf)) 331 return 1; 332 333 return 0; 334 } 335