1 files changed, 657 insertions, 0 deletions

diff --git a/src/debugserver.c b/src/debugserver.c
new file mode 100644
index 0000000..74ade8a
--- /dev/null
+++ b/src/debugserver.c
@@ -0,0 +1,657 @@
+/*
+ * debugserver.c
+ * com.apple.debugserver service implementation.
+ *
+ * Copyright (c) 2019 Nikias Bassen, All Rights Reserved.
+ * Copyright (c) 2014-2015 Martin Szulecki All Rights Reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <string.h>
+#include <stdlib.h>
+#define _GNU_SOURCE 1
+#define __USE_GNU 1
+#include <stdio.h>
+
+#include <libimobiledevice-glue/utils.h>
+
+#include "debugserver.h"
+#include "lockdown.h"
+#include "common/debug.h"
+#include "asprintf.h"
+
+/**
+ * Convert a service_error_t value to a debugserver_error_t value.
+ * Used internally to get correct error codes.
+ *
+ * @param err An service_error_t error code
+ *
+ * @return A matching debugserver_error_t error code,
+ *     DEBUGSERVER_E_UNKNOWN_ERROR otherwise.
+ */
+static debugserver_error_t debugserver_error(service_error_t err)
+{
+        switch (err) {
+                case SERVICE_E_SUCCESS:
+                        return DEBUGSERVER_E_SUCCESS;
+                case SERVICE_E_INVALID_ARG:
+                        return DEBUGSERVER_E_INVALID_ARG;
+                case SERVICE_E_MUX_ERROR:
+                        return DEBUGSERVER_E_MUX_ERROR;
+                case SERVICE_E_SSL_ERROR:
+                        return DEBUGSERVER_E_SSL_ERROR;
+                case SERVICE_E_TIMEOUT:
+                        return DEBUGSERVER_E_TIMEOUT;
+                default:
+                        break;
+        }
+        return DEBUGSERVER_E_UNKNOWN_ERROR;
+}
+
+debugserver_error_t debugserver_client_new(idevice_t device, lockdownd_service_descriptor_t service, debugserver_client_t* client)
+{
+        *client = NULL;
+
+        if (!device || !service || service->port == 0 || !client || *client) {
+                debug_info("Incorrect parameter passed to debugserver_client_new.");
+                return DEBUGSERVER_E_INVALID_ARG;
+        }
+
+        debug_info("Creating debugserver_client, port = %d.", service->port);
+
+        service_client_t parent = NULL;
+        debugserver_error_t ret = debugserver_error(service_client_new(device, service, &parent));
+        if (ret != DEBUGSERVER_E_SUCCESS) {
+                debug_info("Creating base service client failed. Error: %i", ret);
+                return ret;
+        }
+
+        if (service->identifier && (strcmp(service->identifier, DEBUGSERVER_SECURE_SERVICE_NAME) != 0)) {
+                service_disable_bypass_ssl(parent, 1);
+        }
+
+        debugserver_client_t client_loc = (debugserver_client_t) malloc(sizeof(struct debugserver_client_private));
+        client_loc->parent = parent;
+        client_loc->noack_mode = 0;
+        client_loc->cancel_receive = NULL;
+        client_loc->receive_loop_timeout = 1000;
+
+        *client = client_loc;
+
+        debug_info("debugserver_client successfully created.");
+        return DEBUGSERVER_E_SUCCESS;
+}
+
+debugserver_error_t debugserver_client_start_service(idevice_t device, debugserver_client_t * client, const char* label)
+{
+        debugserver_error_t err = DEBUGSERVER_E_UNKNOWN_ERROR;
+        service_client_factory_start_service(device, DEBUGSERVER_SECURE_SERVICE_NAME, (void**)client, label, SERVICE_CONSTRUCTOR(debugserver_client_new), &err);
+        if (err != DEBUGSERVER_E_SUCCESS) {
+                err = DEBUGSERVER_E_UNKNOWN_ERROR;
+                service_client_factory_start_service(device, DEBUGSERVER_SERVICE_NAME, (void**)client, label, SERVICE_CONSTRUCTOR(debugserver_client_new), &err);
+        }
+        return err;
+}
+
+debugserver_error_t debugserver_client_free(debugserver_client_t client)
+{
+        if (!client)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        debugserver_error_t err = debugserver_error(service_client_free(client->parent));
+        client->parent = NULL;
+        free(client);
+
+        return err;
+}
+
+debugserver_error_t debugserver_client_send(debugserver_client_t client, const char* data, uint32_t size, uint32_t *sent)
+{
+        debugserver_error_t res = DEBUGSERVER_E_UNKNOWN_ERROR;
+        int bytes = 0;
+
+        if (!client || !data || (size == 0)) {
+                return DEBUGSERVER_E_INVALID_ARG;
+        }
+
+        debug_info("sending %d bytes", size);
+        res = debugserver_error(service_send(client->parent, data, size, (uint32_t*)&bytes));
+        if (bytes <= 0) {
+                debug_info("ERROR: sending to device failed.");
+        }
+        if (sent) {
+                *sent = (uint32_t)bytes;
+        }
+
+        return res;
+}
+
+debugserver_error_t debugserver_client_receive_with_timeout(debugserver_client_t client, char* data, uint32_t size, uint32_t *received, unsigned int timeout)
+{
+        debugserver_error_t res = DEBUGSERVER_E_UNKNOWN_ERROR;
+        int bytes = 0;
+
+        if (!client || !data || (size == 0)) {
+                return DEBUGSERVER_E_INVALID_ARG;
+        }
+
+        res = debugserver_error(service_receive_with_timeout(client->parent, data, size, (uint32_t*)&bytes, timeout));
+        if (bytes <= 0 && res != DEBUGSERVER_E_TIMEOUT) {
+                debug_info("Could not read data, error %d", res);
+        }
+        if (received) {
+                *received = (uint32_t)bytes;
+        }
+
+        return (bytes > 0) ? DEBUGSERVER_E_SUCCESS : res;
+}
+
+debugserver_error_t debugserver_client_receive(debugserver_client_t client, char* data, uint32_t size, uint32_t *received)
+{
+        debugserver_error_t res = DEBUGSERVER_E_UNKNOWN_ERROR;
+        do {
+                /* Is this allowed to return DEBUGSERVER_E_TIMEOUT and also set data and received? */
+                res = debugserver_client_receive_with_timeout(client, data, size, received, client->receive_loop_timeout);
+        } while (res == DEBUGSERVER_E_TIMEOUT && client->cancel_receive != NULL && !client->cancel_receive());
+        return res;
+}
+
+debugserver_error_t debugserver_command_new(const char* name, int argc, char* argv[], debugserver_command_t* command)
+{
+        int i;
+        debugserver_command_t tmp = (debugserver_command_t) malloc(sizeof(struct debugserver_command_private));
+
+        /* copy name */
+        tmp->name = strdup(name);
+
+        /* copy arguments */
+        tmp->argc = argc;
+        tmp->argv = NULL;
+        if (argc > 0) {
+                tmp->argv = malloc(sizeof(char*) * (argc + 2));
+                for (i = 0; i < argc; i++) {
+                        tmp->argv[i] = strdup(argv[i]);
+                }
+                tmp->argv[i+1] = NULL;
+        }
+
+        /* return */
+        *command = tmp;
+
+        return DEBUGSERVER_E_SUCCESS;
+}
+
+debugserver_error_t debugserver_command_free(debugserver_command_t command)
+{
+        int i;
+        debugserver_error_t res = DEBUGSERVER_E_UNKNOWN_ERROR;
+
+        if (!command)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        if (command) {
+                if (command->name)
+                        free(command->name);
+                if (command->argv && command->argc) {
+                        for (i = 0; i < command->argc; i++) {
+                                free(command->argv[i]);
+                        }
+                        free(command->argv);
+                }
+                free(command);
+                res = DEBUGSERVER_E_SUCCESS;
+        }
+
+        return res;
+}
+
+static int debugserver_hex2int(char c)
+{
+        if (c >= '0' && c <= '9')
+                return c - '0';
+        else if (c >= 'a' && c <= 'f')
+                return 10 + c - 'a';
+        else if (c >= 'A' && c <= 'F')
+                return 10 + c - 'A';
+        else
+                return c;
+}
+
+static char debugserver_int2hex(int x)
+{
+        const char *hexchars = "0123456789ABCDEF";
+        return hexchars[x];
+}
+
+#define DEBUGSERVER_HEX_ENCODE_FIRST_BYTE(byte) debugserver_int2hex(((byte) >> 0x4) & 0xf)
+#define DEBUGSERVER_HEX_ENCODE_SECOND_BYTE(byte) debugserver_int2hex((byte) & 0xf)
+#define DEBUGSERVER_HEX_DECODE_FIRST_BYTE(byte) (((byte) >> 0x4) & 0xf)
+#define DEBUGSERVER_HEX_DECODE_SECOND_BYTE(byte) ((byte) & 0xf)
+
+static uint32_t debugserver_get_checksum_for_buffer(const char* buffer, uint32_t size)
+{
+        uint32_t checksum = 0;
+        uint32_t i;
+
+        for (i = 0; i < size; i++) {
+                checksum += buffer[i];
+        }
+
+        return checksum;
+}
+
+static int debugserver_response_is_checksum_valid(const char* response, uint32_t size)
+{
+        uint32_t checksum = 0;
+        if ((size - DEBUGSERVER_CHECKSUM_HASH_LENGTH - 1) > 0)
+                checksum = debugserver_get_checksum_for_buffer(&response[1], size - DEBUGSERVER_CHECKSUM_HASH_LENGTH - 1);
+
+        debug_info("checksum: 0x%x", checksum);
+
+        if ((unsigned)debugserver_hex2int(response[size - 2]) != DEBUGSERVER_HEX_DECODE_FIRST_BYTE(checksum))
+                return 0;
+
+        if ((unsigned)debugserver_hex2int(response[size - 1]) != DEBUGSERVER_HEX_DECODE_SECOND_BYTE(checksum))
+                return 0;
+
+        debug_info("valid checksum");
+
+        return 1;
+}
+
+void debugserver_encode_string(const char* buffer, char** encoded_buffer, uint32_t* encoded_length)
+{
+        uint32_t position;
+        uint32_t index;
+        uint32_t length = strlen(buffer);
+        *encoded_length = (2 * length) + DEBUGSERVER_CHECKSUM_HASH_LENGTH + 1;
+
+        *encoded_buffer = malloc(sizeof(char) * (*encoded_length));
+        memset(*encoded_buffer, '\0', *encoded_length);
+        for (position = 0, index = 0; index < length; index++) {
+                position = (index * (2 * sizeof(char)));
+                (*encoded_buffer)[position] = DEBUGSERVER_HEX_ENCODE_FIRST_BYTE(buffer[index]);
+                (*encoded_buffer)[position + 1] = DEBUGSERVER_HEX_ENCODE_SECOND_BYTE(buffer[index]);
+        }
+}
+
+void debugserver_decode_string(const char *encoded_buffer, size_t encoded_length, char** buffer)
+{
+        *buffer = malloc(sizeof(char) * ((encoded_length / 2)+1));
+        char* t = *buffer;
+        const char *f = encoded_buffer;
+        const char *fend = f + encoded_length;
+        while (f < fend) {
+                *t++ = debugserver_hex2int(*f) << 4 | debugserver_hex2int(f[1]);
+                f += 2;
+        }
+        *t = '\0';
+}
+
+static void debugserver_format_command(const char* prefix, const char* command, const char* arguments, int calculate_checksum, char** buffer, uint32_t* size)
+{
+        char checksum_hash[DEBUGSERVER_CHECKSUM_HASH_LENGTH + 1] = {'#', '0', '0', '\0'};
+        char* encoded = NULL;
+        uint32_t encoded_length = 0;
+
+        if (arguments) {
+                /* arguments must be hex encoded */
+                debugserver_encode_string(arguments, &encoded, &encoded_length);
+        } else {
+                encoded = NULL;
+        }
+
+        char* encoded_command = string_concat(command, encoded, NULL);
+        encoded_length = strlen(encoded_command);
+
+        if (calculate_checksum) {
+                uint32_t checksum = debugserver_get_checksum_for_buffer(encoded_command, encoded_length);
+                checksum_hash[1] = DEBUGSERVER_HEX_ENCODE_FIRST_BYTE(checksum);
+                checksum_hash[2] = DEBUGSERVER_HEX_ENCODE_SECOND_BYTE(checksum);
+        }
+
+        *buffer = string_concat(prefix, encoded_command, checksum_hash, NULL);
+        *size = strlen(prefix) + strlen(encoded_command) + DEBUGSERVER_CHECKSUM_HASH_LENGTH;
+
+        debug_info("formatted command: %s size: %d checksum: 0x%s", *buffer, *size, checksum_hash);
+
+        if (encoded_command)
+                free(encoded_command);
+
+        if (encoded)
+                free(encoded);
+}
+
+static debugserver_error_t debugserver_client_send_ack(debugserver_client_t client)
+{
+        debug_info("sending ACK");
+        return debugserver_client_send(client, "+", sizeof(char), NULL);
+}
+
+static debugserver_error_t debugserver_client_send_noack(debugserver_client_t client)
+{
+        debug_info("sending !ACK");
+        return debugserver_client_send(client, "-", sizeof(char), NULL);
+}
+
+debugserver_error_t debugserver_client_set_ack_mode(debugserver_client_t client, int enabled)
+{
+        if (!client)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        client->noack_mode = (enabled == 0)? 1: 0;
+
+        debug_info("ack mode: %s", client->noack_mode == 0 ? "on": "off");
+
+        return DEBUGSERVER_E_SUCCESS;
+}
+
+debugserver_error_t debugserver_client_set_receive_params(debugserver_client_t client, int (*cancel_receive)(), int receive_loop_timeout)
+{
+        if (!client)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        client->cancel_receive = cancel_receive;
+        client->receive_loop_timeout = receive_loop_timeout;
+
+        debug_info("receive params: cancel_receive %s, receive_loop_timeout %dms", (client->cancel_receive == NULL ? "unset": "set"), client->receive_loop_timeout);
+
+        return DEBUGSERVER_E_SUCCESS;
+}
+
+static debugserver_error_t debugserver_client_receive_internal_char(debugserver_client_t client, char* received_char)
+{
+        debugserver_error_t res = DEBUGSERVER_E_SUCCESS;
+        uint32_t bytes = 0;
+
+        /* we loop here as we expect an answer */
+        res = debugserver_client_receive(client, received_char, sizeof(char), &bytes);
+        if (res != DEBUGSERVER_E_SUCCESS) {
+                return res;
+        }
+        if (bytes != 1) {
+                debug_info("received %d bytes when asking for %d!", bytes, sizeof(char));
+                return DEBUGSERVER_E_UNKNOWN_ERROR;
+        }
+        return res;
+}
+
+debugserver_error_t debugserver_client_receive_response(debugserver_client_t client, char** response, size_t* response_size)
+{
+        debugserver_error_t res = DEBUGSERVER_E_SUCCESS;
+
+        char data = '\0';
+        int skip_prefix = 0;
+
+        char* buffer = malloc(1024);
+        uint32_t buffer_size = 0;
+        uint32_t buffer_capacity = 1024;
+
+        if (response)
+                *response = NULL;
+
+        if (!client->noack_mode) {
+                debug_info("attempting to receive ACK (+)");
+                res = debugserver_client_receive_internal_char(client, &data);
+                if (res != DEBUGSERVER_E_SUCCESS) {
+                        goto cleanup;
+                }
+                if (data == '+') {
+                        debug_info("received ACK (+)");
+                } else if (data == '$') {
+                        debug_info("received prefix ($)");
+                        buffer[0] = '$';
+                        buffer_size = 1;
+                        skip_prefix = 1;
+                } else {
+                        debug_info("unrecognized response when looking for ACK: %c", data);
+                        goto cleanup;
+                }
+        }
+
+        debug_info("skip_prefix: %d", skip_prefix);
+
+        if (!skip_prefix) {
+                debug_info("attempting to receive prefix ($)");
+                res = debugserver_client_receive_internal_char(client, &data);
+                if (res != DEBUGSERVER_E_SUCCESS) {
+                        goto cleanup;
+                }
+                if (data == '$') {
+                        debug_info("received prefix ($)");
+                        buffer[0] = '$';
+                        buffer_size = 1;
+                } else {
+                        debug_info("unrecognized response when looking for prefix: %c", data);
+                        goto cleanup;
+                }
+        }
+
+        uint32_t checksum_length = DEBUGSERVER_CHECKSUM_HASH_LENGTH;
+        int receiving_checksum_response = 0;
+        debug_info("attempting to read up response until checksum");
+
+        while ((checksum_length > 0)) {
+                res = debugserver_client_receive_internal_char(client, &data);
+                if (res != DEBUGSERVER_E_SUCCESS) {
+                        goto cleanup;
+                }
+                if (data == '#') {
+                        receiving_checksum_response = 1;
+                }
+                if (receiving_checksum_response) {
+                        checksum_length--;
+                }
+                if (buffer_size + 1 >= buffer_capacity) {
+                        char* newbuffer = realloc(buffer, buffer_capacity+1024);
+                        if (!newbuffer) {
+                                return DEBUGSERVER_E_UNKNOWN_ERROR;
+                        }
+                        buffer = newbuffer;
+                        buffer_capacity += 1024;
+                }
+                buffer[buffer_size] = data;
+                buffer_size += sizeof(char);
+        }
+        debug_info("validating response checksum...");
+        if (client->noack_mode || debugserver_response_is_checksum_valid(buffer, buffer_size)) {
+                if (response) {
+                        /* assemble response string */
+                        uint32_t resp_size = sizeof(char) * (buffer_size - DEBUGSERVER_CHECKSUM_HASH_LENGTH - 1);
+                        *response = (char*)malloc(resp_size + 1);
+                        memcpy(*response, buffer + 1, resp_size);
+                        (*response)[resp_size] = '\0';
+                        if (response_size) *response_size = resp_size;
+                }
+                if (!client->noack_mode) {
+                        /* confirm valid command */
+                        debugserver_client_send_ack(client);
+                }
+        } else {
+                /* response was invalid */
+                res = DEBUGSERVER_E_RESPONSE_ERROR;
+                if (!client->noack_mode) {
+                        /* report invalid command */
+                        debugserver_client_send_noack(client);
+                }
+        }
+
+cleanup:
+        if (response) {
+                debug_info("response: %s", *response);
+        }
+
+        if (buffer)
+                free(buffer);
+
+        return res;
+}
+
+debugserver_error_t debugserver_client_send_command(debugserver_client_t client, debugserver_command_t command, char** response, size_t* response_size)
+{
+        debugserver_error_t res = DEBUGSERVER_E_SUCCESS;
+        int i;
+        uint32_t bytes = 0;
+
+        char* send_buffer = NULL;
+        uint32_t send_buffer_size = 0;
+
+        char* command_arguments = NULL;
+
+        /* concat all arguments */
+        for (i = 0; i < command->argc; i++) {
+                debug_info("argv[%d]: %s", i, command->argv[i]);
+                command_arguments = string_append(command_arguments, command->argv[i], NULL);
+        }
+
+        debug_info("command_arguments(%d): %s", command->argc, command_arguments);
+
+        /* encode command arguments, add checksum if required and assemble entire command */
+        debugserver_format_command("$", command->name, command_arguments, 1, &send_buffer, &send_buffer_size);
+
+        debug_info("sending encoded command: %s", send_buffer);
+
+        res = debugserver_client_send(client, send_buffer, send_buffer_size, &bytes);
+        debug_info("command result: %d", res);
+        if (res != DEBUGSERVER_E_SUCCESS) {
+                goto cleanup;
+        }
+
+        /* receive response */
+        res = debugserver_client_receive_response(client, response, response_size);
+        debug_info("response result: %d", res);
+        if (res != DEBUGSERVER_E_SUCCESS) {
+                goto cleanup;
+        }
+
+        if (response) {
+                debug_info("received response: %s", *response);
+        }
+
+        /* disable sending ack on the client */
+        if (!strncmp(command->name, "QStartNoAckMode", 16)) {
+                debugserver_client_set_ack_mode(client, 0);
+        }
+
+cleanup:
+        if (command_arguments)
+                free(command_arguments);
+
+        if (send_buffer)
+                free(send_buffer);
+
+        return res;
+}
+
+debugserver_error_t debugserver_client_set_environment_hex_encoded(debugserver_client_t client, const char* env, char** response)
+{
+        if (!client || !env)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        debugserver_error_t result = DEBUGSERVER_E_UNKNOWN_ERROR;
+        char* env_tmp = strdup(env);
+        char* env_arg[2] = { env_tmp, NULL };
+
+        debugserver_command_t command = NULL;
+        debugserver_command_new("QEnvironmentHexEncoded:", 1, env_arg, &command);
+        result = debugserver_client_send_command(client, command, response, NULL);
+        debugserver_command_free(command);
+
+        free(env_tmp);
+
+        return result;
+}
+
+debugserver_error_t debugserver_client_set_argv(debugserver_client_t client, int argc, char* argv[], char** response)
+{
+        if (!client || !argc)
+                return DEBUGSERVER_E_INVALID_ARG;
+
+        debugserver_error_t result = DEBUGSERVER_E_UNKNOWN_ERROR;
+        char *pkt = NULL;
+        size_t pkt_len = 0;
+        int i = 0;
+
+        /* calculate total length */
+        while (i < argc && argv && argv[i]) {
+                char *prefix = NULL;
+                int ret = asprintf(&prefix, ",%zu,%d,", strlen(argv[i]) * 2, i);
+                if (ret < 0 || prefix == NULL) {
+                        debug_info("asprintf failed, out of memory?");
+                        return DEBUGSERVER_E_UNKNOWN_ERROR;
+                }
+                pkt_len += strlen(prefix) + strlen(argv[i]) * 2;
+                free(prefix);
+                i++;
+        }
+
+        /* allocate packet and initialize it */
+        pkt = (char *) malloc(pkt_len + 1);
+        memset(pkt, 0, pkt_len + 1);
+
+        char *pktp = pkt;
+
+        i = 0;
+        while (i < argc && argv && argv[i]) {
+                debug_info("argv[%d] = \"%s\"", i, argv[i]);
+
+                char *prefix = NULL;
+                char *m = NULL;
+                size_t arg_len = strlen(argv[i]);
+                size_t arg_hexlen = arg_len * 2;
+
+                int ret = asprintf(&prefix, ",%zu,%d,", arg_hexlen, i);
+                if (ret < 0 || prefix == NULL) {
+                        debug_info("asprintf failed, out of memory?");
+                        return DEBUGSERVER_E_UNKNOWN_ERROR;
+                }
+
+                m = (char *) malloc(arg_hexlen);
+                char *p = m;
+                char *q = (char*)argv[i];
+                while (*q) {
+                        *p++ = DEBUGSERVER_HEX_ENCODE_FIRST_BYTE(*q);
+                        *p++ = DEBUGSERVER_HEX_ENCODE_SECOND_BYTE(*q);
+                        q++;
+                }
+
+                memcpy(pktp, prefix, strlen(prefix));
+                pktp += strlen(prefix);
+
+                memcpy(pktp, m, arg_hexlen);
+                pktp += arg_hexlen;
+
+                free(prefix);
+                free(m);
+
+                i++;
+        }
+
+        pkt[0] = 'A';
+
+        debugserver_command_t command = NULL;
+        debugserver_command_new(pkt, 0, NULL, &command);
+        result = debugserver_client_send_command(client, command, response, NULL);
+        debugserver_command_free(command);
+
+        if (pkt)
+                free(pkt);
+
+        return result;
+}