Require explicit username to drop privs

2 files changed, 12 insertions, 8 deletions

diff --git a/daemon/main.c b/daemon/main.c
index 363f3d5..18b28a8 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -56,7 +56,7 @@ int should_discover;
 static int verbose = 0;
 static int foreground = 0;
 static int drop_privileges = 0;
-static const char *drop_user = "usbmux";
+static const char *drop_user = NULL;
 static int opt_udev = 0;
 static int opt_exit = 0;
 static int exit_signal = 0;
@@ -336,8 +336,7 @@ 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-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-U|--user USER            Change to this user after startup (needs usb privileges).\n");
         printf("\t-u|--udev                 Run in udev operation mode.\n");
         printf("\t-x|--exit                 Tell a running instance to exit if there are no devices\n");
         printf("\t                          connected (must be in udev mode).\n");
@@ -361,7 +360,7 @@ static void parse_opts(int argc, char **argv)
         int c;
 
         while (1) {
-                c = getopt_long(argc, argv, "hfvuU::xX", longopts, (int *) 0);
+                c = getopt_long(argc, argv, "hfvuU:xX", longopts, (int *) 0);
                 if (c == -1) {
                         break;
                 }
@@ -378,8 +377,7 @@ static void parse_opts(int argc, char **argv)
                         break;
                 case 'U':
                         drop_privileges = 1;
-                        if(optarg)
-                                drop_user = optarg;
+                        drop_user = optarg;
                         break;
                 case 'u':
                         opt_udev = 1;
@@ -519,7 +517,13 @@ int main(int argc, char *argv[])
 
         // drop elevated privileges
         if (drop_privileges && (getuid() == 0 || geteuid() == 0)) {
-                struct passwd *pw = getpwnam(drop_user);
+                struct passwd *pw;
+                if (!drop_user) {
+                        usbmuxd_log(LL_FATAL, "No user to drop privileges to?");
+                        res = -1;
+                        goto terminate;
+                }
+                pw = getpwnam(drop_user);
                 if (!pw) {
                         usbmuxd_log(LL_FATAL, "Dropping privileges failed, check if user '%s' exists!", drop_user);
                         res = -1;
diff --git a/udev/85-usbmuxd.rules.in b/udev/85-usbmuxd.rules.in
index f68a5fa..f9c8376 100644
--- a/udev/85-usbmuxd.rules.in
+++ b/udev/85-usbmuxd.rules.in
@@ -1,7 +1,7 @@
 # usbmuxd (iPhone "Apple Mobile Device" MUXer listening on /var/run/usbmuxd)
 
 # Forces iPhone 1.0, 3G, 3GS and iPodTouch 1 and 2 to USB configuration 3 and run usbmuxd
-ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="05ac", ATTR{idProduct}=="129[0-9]", ATTR{bConfigurationValue}!="$attr{bNumConfigurations}", ATTR{bConfigurationValue}="$attr{bNumConfigurations}", RUN+="@CMAKE_INSTALL_PREFIX@/sbin/usbmuxd -u -U"
+ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="05ac", ATTR{idProduct}=="129[0-9]", ATTR{bConfigurationValue}!="$attr{bNumConfigurations}", ATTR{bConfigurationValue}="$attr{bNumConfigurations}", RUN+="@CMAKE_INSTALL_PREFIX@/sbin/usbmuxd -u -U usbmux"
 
 # Exit usbmuxd when the last phone is removed
 ACTION=="remove", SUBSYSTEM=="usb", ENV{PRODUCT}=="5ac/129[0-9]/*", ENV{INTERFACE}=="255/*", RUN+="@CMAKE_INSTALL_PREFIX@/sbin/usbmuxd -x"