macOS: Avoid deviceinterfaced races during DFU reconnect

During Port DFU-to-DFU re-enumeration, macOS deviceinterfaced daemon can
acquire the USB interface first, making idevicerestore time out waiting
for DFU reconnection.

Add experimental flag: --exclusive-usb that keeps deviceinterfaced from
claiming the USB device for the duration of the restore, by booting it
out or repeatedly terminating it when bootout is denied (SIP on), then
reloading and starting it again on exit.

idevicerestore itself does not need to run as root for this. Only the
launchctl subcommands that manage the system-domain deviceinterfaced
daemon (bootout, bootstrap, kickstart, kill) are elevated individually
via sudo, which may prompt for a password on the controlling terminal.
Read-only queries (print) are run unprivileged. Document how to allow
these specific commands via a scoped sudoers(5) NOPASSWD rule for
unattended use.

Co-authored-by: Nikias Bassen <nikias@gmx.li>

1 files changed, 39 insertions, 0 deletions

diff --git a/src/idevicerestore.c b/src/idevicerestore.c
index 04070a1..11d7ec4 100644
--- a/src/idevicerestore.c
+++ b/src/idevicerestore.c
@@ -61,6 +61,10 @@
 
 #include "locking.h"
 
+#ifdef __APPLE__
+#include "deviceinterfaced.h"
+#endif
+
 #define VERSION_XML "version.xml"
 
 #ifndef IDEVICERESTORE_NOMAIN
@@ -91,6 +95,9 @@ static struct option longopts[] = {
 	{ "ignore-errors",  no_argument,       NULL,  1  },
 	{ "variant",        required_argument, NULL,  2  },
 	{ "logfile",        required_argument, NULL,  3  },
+#ifdef __APPLE__
+	{ "exclusive-usb",  no_argument,       NULL,  4  },
+#endif
 	{ NULL, 0, NULL, 0 }
 };
 
@@ -101,6 +108,14 @@ static void usage(int argc, char* argv[], int err)
 #else
 #define PWN_FLAG_LINE ""
 #endif
+#ifdef __APPLE__
+#define EXCLUSIVE_USB_ACCESS_FLAG_LINE \
+	"  --exclusive-usb       Keep deviceinterfaced from claiming the USB device\n" \
+	"                        during the restore (may prompt for your password\n" \
+	"                        via sudo)\n"
+#else
+#define EXCLUSIVE_USB_ACCESS_FLAG_LINE ""
+#endif
 	char* name = strrchr(argv[0], '/');
 	fprintf((err) ? stderr : stdout,
 	"Usage: %s [OPTIONS] PATH\n" \
@@ -141,6 +156,7 @@ static void usage(int argc, char* argv[], int err)
 	"  -v, --version         Print version information\n" \
 	"\n" \
 	"Advanced/experimental options:\n"
+	EXCLUSIVE_USB_ACCESS_FLAG_LINE \
 	"  -c, --custom          Restore with a custom firmware (requires bootrom exploit)\n" \
 	"  -s, --server URL      Override default signing server request URL\n" \
 	"  -x, --exclude         Exclude nor/baseband upgrade (legacy devices)\n" \
@@ -1777,6 +1793,9 @@ int main(int argc, char* argv[])
 	int ipsw_info = 0;
 	int result = 0;
 	const char* logfile = NULL;
+#ifdef __APPLE__
+	int exclusive_usb_access = 0;
+#endif
 
 	logger_set_print_func(tty_print);
 
@@ -1978,6 +1997,12 @@ int main(int argc, char* argv[])
 			logfile = optarg;
 			break;
 
+#ifdef __APPLE__
+		case 4:
+			exclusive_usb_access = 1;
+			break;
+#endif
+
 		default:
 			usage(argc, argv, 1);
 			return EXIT_FAILURE;
@@ -2036,12 +2061,26 @@ int main(int argc, char* argv[])
 
 	curl_global_init(CURL_GLOBAL_ALL);
 
+#ifdef __APPLE__
+	if (exclusive_usb_access && deviceinterfaced_control_start() < 0) {
+		idevicerestore_client_free(client);
+		curl_global_cleanup();
+		return EXIT_FAILURE;
+	}
+#endif
+
 	client->flags |= FLAG_IN_PROGRESS;
 	result = idevicerestore_start(client);
 	client->flags &= ~FLAG_IN_PROGRESS;
 
 	idevicerestore_client_free(client);
 
+#ifdef __APPLE__
+	if (exclusive_usb_access) {
+		deviceinterfaced_control_stop();
+	}
+#endif
+
 	curl_global_cleanup();
 
 	return (result == 0) ? EXIT_SUCCESS : EXIT_FAILURE;