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_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 }; 108 109 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 } 139 140 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 } 189 190 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 } 231 232 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 } 248 249 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 } 291 292 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