modprobe: fix a segfault when modprobe is called with no arguments at all

function                                             old     new   delta
modprobe_main                                        559     535     -24

2 files changed, 29 insertions, 25 deletions

diff --git a/modutils/modprobe.c b/modutils/modprobe.c
index 20b9a74aa..40a1e6627 100644
--- a/modutils/modprobe.c
+++ b/modutils/modprobe.c
@@ -203,18 +203,17 @@ int modprobe_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int modprobe_main(int argc UNUSED_PARAM, char **argv)
 {
         struct utsname uts;
-        int num_modules, i, rc;
+        int rc;
+        unsigned opt;
         llist_t *options = NULL;
-        parser_t *parser;
 
         opt_complementary = "q-v:v-q";
-        getopt32(argv, INSMOD_OPTS MODPROBE_OPTS INSMOD_ARGS,
+        opt = getopt32(argv, INSMOD_OPTS MODPROBE_OPTS INSMOD_ARGS,
                  NULL, NULL);
         argv += optind;
-        argc -= optind;
 
-        if (option_mask32 & (MODPROBE_OPT_DUMP_ONLY | MODPROBE_OPT_LIST_ONLY |
-                             MODPROBE_OPT_SHOW_ONLY))
+        if (opt & (MODPROBE_OPT_DUMP_ONLY | MODPROBE_OPT_LIST_ONLY |
+                                MODPROBE_OPT_SHOW_ONLY))
                 bb_error_msg_and_die("not supported");
 
         /* goto modules location */
@@ -222,40 +221,44 @@ int modprobe_main(int argc UNUSED_PARAM, char **argv)
         uname(&uts);
         xchdir(uts.release);
 
-        if (option_mask32 & (MODPROBE_OPT_REMOVE | MODPROBE_OPT_INSERT_ALL)) {
-                /* each parameter is a module name */
-                num_modules = argc;
-                if (num_modules == 0) {
+        if (!argv[0]) {
+                if (opt & MODPROBE_OPT_REMOVE) {
                         if (bb_delete_module(NULL, O_NONBLOCK|O_EXCL) != 0)
                                 bb_perror_msg_and_die("rmmod");
-                        return EXIT_SUCCESS;
                 }
-        } else {
-                /* the only module, the rest of parameters are options */
-                num_modules = 1;
+                return EXIT_SUCCESS;
+        }
+        if (!(opt & MODPROBE_OPT_INSERT_ALL)) {
+                /* If not -a, we have only one module name,
+                 * the rest of parameters are options */
                 add_option(&options, NULL, parse_cmdline_module_options(argv));
+                argv[1] = NULL;
         }
 
         /* cache modules */
-        parser = config_open2("/proc/modules", fopen_for_read);
-        if (parser) {
+        {
                 char *s;
+                parser_t *parser = config_open2("/proc/modules", fopen_for_read);
                 while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY))
                         llist_add_to(&loaded, xstrdup(s));
                 config_close(parser);
         }
 
-        for (i = 0; i < num_modules; i++) {
+        while (*argv) {
+                const char *arg = *argv;
                 struct modprobe_conf *conf;
 
-                conf = xzalloc(sizeof(struct modprobe_conf));
+                conf = xzalloc(sizeof(*conf));
                 conf->options = options;
-                filename2modname(argv[i], conf->probename);
+                filename2modname(arg, conf->probename);
                 read_config(conf, "/etc/modprobe.conf");
                 read_config(conf, "/etc/modprobe.d");
-                if (ENABLE_FEATURE_MODUTILS_SYMBOLS &&
-                    conf->aliases == NULL && strncmp(argv[i], "symbol:", 7) == 0)
+                if (ENABLE_FEATURE_MODUTILS_SYMBOLS
+                 && conf->aliases == NULL
+                 && strncmp(arg, "symbol:", 7) == 0
+                ) {
                         read_config(conf, "modules.symbols");
+                }
 
                 if (ENABLE_FEATURE_MODUTILS_ALIAS && conf->aliases == NULL)
                         read_config(conf, "modules.alias");
@@ -263,11 +266,11 @@ int modprobe_main(int argc UNUSED_PARAM, char **argv)
                 if (conf->aliases == NULL) {
                         /* Try if module by literal name is found; literal
                          * names are blacklist only if '-b' is given. */
-                        if (!(option_mask32 & MODPROBE_OPT_BLACKLIST) ||
+                        if (!(opt & MODPROBE_OPT_BLACKLIST) ||
                             check_blacklist(conf, conf->probename)) {
                                 rc = do_modprobe(conf, conf->probename);
-                                if (rc < 0 && !(option_mask32 & INSMOD_OPT_SILENT))
-                                        bb_error_msg("Module %s not found.", argv[i]);
+                                if (rc < 0 && !(opt & INSMOD_OPT_SILENT))
+                                        bb_error_msg("Module %s not found.", arg);
                         }
                 } else {
                         /* Probe all aliases */
@@ -279,6 +282,7 @@ int modprobe_main(int argc UNUSED_PARAM, char **argv)
                                         free(realname);
                         }
                 }
+                argv++;
         }
 
         return EXIT_SUCCESS;
diff --git a/modutils/modutils.c b/modutils/modutils.c
index 18ea5374e..10b49c901 100644
--- a/modutils/modutils.c
+++ b/modutils/modutils.c
@@ -106,7 +106,7 @@ char * FAST_FUNC parse_cmdline_module_options(char **argv)
         while (*++argv) {
                 options = xrealloc(options, optlen + 2 + strlen(*argv) + 2);
                 /* Spaces handled by "" pairs, but no way of escaping quotes */
-                optlen += sprintf(options + optlen, (strchr(*argv,' ') ? "\"%s\" " : "%s "), *argv);
+                optlen += sprintf(options + optlen, (strchr(*argv, ' ') ? "\"%s\" " : "%s "), *argv);
         }
         return options;
 }