diff options
| -rw-r--r-- | usbmuxd/main.c | 58 |
1 files changed, 39 insertions, 19 deletions
diff --git a/usbmuxd/main.c b/usbmuxd/main.c index ec52ce0..f1aa1cc 100644 --- a/usbmuxd/main.c +++ b/usbmuxd/main.c @@ -36,6 +36,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA #include <sys/fcntl.h> #include <getopt.h> #include <pwd.h> +#include <grp.h> #include "log.h" #include "usb.h" @@ -50,6 +51,7 @@ int should_exit; static int verbose = 0; static int foreground = 0; static int drop_privileges = 0; +static const char *drop_user = "usbmux"; static int opt_udev = 0; static int opt_exit = 0; static int exit_signal = 0; @@ -236,8 +238,9 @@ static void usage() printf("\t-h|--help Print this message.\n"); printf("\t-v|--verbose Be verbose (use twice or more to increase).\n"); printf("\t-f|--foreground Do not daemonize (implies one -v).\n"); - printf("\t-d|--drop-privileges Drop privileges after startup.\n"); - printf("\t-u|--udev Run in udev operation mode.\n"); + printf("\t-u|--user[=USER] Change to this user after startup (needs usb privileges).\n"); + printf("\t If USER is not specified, defaults to usbmux.\n"); + printf("\t-d|--udev Run in udev operation mode.\n"); printf("\t-x|--exit Tell a running instance to exit.\n"); printf("\t-X|--force-exit Tell a running instance to exit, even if\n"); printf("\t there are still devices connected.\n"); @@ -250,8 +253,8 @@ static void parse_opts(int argc, char **argv) {"help", 0, NULL, 'h'}, {"foreground", 0, NULL, 'f'}, {"verbose", 0, NULL, 'v'}, - {"drop-privileges", 0, NULL, 'd'}, - {"udev", 0, NULL, 'u'}, + {"user", 2, NULL, 'u'}, + {"udev", 0, NULL, 'd'}, {"exit", 0, NULL, 'x'}, {"force-exit", 0, NULL, 'X'}, {NULL, 0, NULL, 0} @@ -259,7 +262,7 @@ static void parse_opts(int argc, char **argv) int c; while (1) { - c = getopt_long(argc, argv, "hfvduxX", longopts, (int *) 0); + c = getopt_long(argc, argv, "hfvdu::xX", longopts, (int *) 0); if (c == -1) { break; } @@ -274,10 +277,12 @@ static void parse_opts(int argc, char **argv) case 'v': ++verbose; break; - case 'd': + case 'u': drop_privileges = 1; + if(optarg) + drop_user = optarg; break; - case 'u': + case 'd': opt_udev = 1; break; case 'x': @@ -403,23 +408,38 @@ int main(int argc, char *argv[]) // drop elevated privileges if (drop_privileges && (getuid() == 0 || geteuid() == 0)) { - struct passwd *pw = getpwnam("nobody"); - if (pw) { - setuid(pw->pw_uid); - } else { - usbmuxd_log(LL_ERROR, - "ERROR: Dropping privileges failed, check if user 'nobody' exists! Will now terminate."); - log_disable_syslog(); - exit(EXIT_FAILURE); + struct passwd *pw = getpwnam(drop_user); + if (!pw) { + usbmuxd_log(LL_FATAL, "Dropping privileges failed, check if user '%s' exists!", drop_user); + res = 1; + goto terminate; + } + + if ((res = initgroups(drop_user, pw->pw_gid)) < 0) { + usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set supplementary groups)"); + goto terminate; + } + if ((res = setgid(pw->pw_gid)) < 0) { + usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set group ID to %d)", pw->pw_gid); + goto terminate; + } + if ((res = setuid(pw->pw_uid)) < 0) { + usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set user ID to %d)", pw->pw_uid); + goto terminate; } // security check if (setuid(0) != -1) { - usbmuxd_log(LL_ERROR, "ERROR: Failed to drop privileges properly!"); - log_disable_syslog(); - exit(EXIT_FAILURE); + usbmuxd_log(LL_FATAL, "Failed to drop privileges properly!"); + res = 1; + goto terminate; + } + if (getuid() != pw->pw_uid || getgid() != pw->pw_gid) { + usbmuxd_log(LL_FATAL, "Failed to drop privileges properly!"); + res = 1; + goto terminate; } - usbmuxd_log(LL_NOTICE, "Successfully dropped privileges"); + usbmuxd_log(LL_NOTICE, "Successfully dropped privileges to '%s'", drop_user); } res = main_loop(listenfd); |