Add support for Apple's OPACK encoding and TLV format

1 files changed, 476 insertions, 0 deletions

diff --git a/src/opack.c b/src/opack.c
new file mode 100644
index 0000000..9e7fa73
--- /dev/null
+++ b/src/opack.c
@@ -0,0 +1,476 @@
+/*
+ * opack.c
+ * "opack" format encoder/decoder implementation.
+ *
+ * Copyright (c) 2021 Nikias Bassen, 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 <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "common.h"
+#include "libimobiledevice-glue/cbuf.h"
+#include "libimobiledevice-glue/opack.h"
+#include "endianness.h"
+
+#define MAC_EPOCH 978307200
+
+static void opack_encode_node(plist_t node, struct char_buf* cbuf)
+{
+	plist_type type = plist_get_node_type(node);
+	switch (type) {
+		case PLIST_DICT: {
+			uint32_t count = plist_dict_get_size(node);
+			uint8_t blen = 0xEF;
+			if (count < 15)
+				blen = (uint8_t)count-32;	
+			char_buf_append(cbuf, 1, &blen);
+			plist_dict_iter iter = NULL;
+			plist_dict_new_iter(node, &iter);
+			if (iter) {
+				plist_t sub = NULL;
+				do {
+					sub = NULL;
+					plist_dict_next_item(node, iter, NULL, &sub);
+					if (sub) {
+						plist_t key = plist_dict_item_get_key(sub);
+						opack_encode_node(key, cbuf);
+						opack_encode_node(sub, cbuf);
+					}
+				} while (sub);
+				free(iter);
+				if (count > 14) {
+					uint8_t term = 0x03;
+					char_buf_append(cbuf, 1, &term);
+				}
+			}
+		}	break;
+		case PLIST_ARRAY: {
+			uint32_t count = plist_array_get_size(node);
+			uint8_t blen = 0xDF;
+			if (count < 15)
+				blen = (uint8_t)(count-48);
+			char_buf_append(cbuf, 1, &blen);
+			plist_array_iter iter = NULL;
+			plist_array_new_iter(node, &iter);
+			if (iter) {
+				plist_t sub = NULL;
+				do {
+					sub = NULL;
+					plist_array_next_item(node, iter, &sub);
+					if (sub) {
+						opack_encode_node(sub, cbuf);
+					}
+				} while (sub);
+				free(iter);
+				if (count > 14) {
+					uint8_t term = 0x03;
+					char_buf_append(cbuf, 1, &term);
+				}
+			}
+		}	break;
+		case PLIST_BOOLEAN: {
+			uint8_t bval = 2 - plist_bool_val_is_true(node);
+			char_buf_append(cbuf, 1, &bval);
+		}	break;
+		case PLIST_UINT: {
+			uint64_t u64val = 0;
+			plist_get_uint_val(node, &u64val);
+			if ((uint8_t)u64val == u64val) {
+				uint8_t u8val = (uint8_t)u64val;
+				if (u8val > 0x27) {
+					uint8_t blen = 0x30;
+					char_buf_append(cbuf, 1, &blen);
+					char_buf_append(cbuf, 1, &u8val);
+				} else {
+					u8val += 8;
+					char_buf_append(cbuf, 1, &u8val);
+				}
+			} else if ((uint32_t)u64val == u64val) {
+				uint8_t blen = 0x32;
+				char_buf_append(cbuf, 1, &blen);
+				uint32_t u32val = (uint32_t)u64val;
+				u32val = htole32(u32val);
+				char_buf_append(cbuf, 4, (unsigned char*)&u32val);
+			} else {
+				uint8_t blen = 0x33;
+				char_buf_append(cbuf, 1, &blen);
+				u64val = htole64(u64val);
+				char_buf_append(cbuf, 8, (unsigned char*)&u64val);
+			}
+		}	break;
+		case PLIST_REAL: {
+			double dval = 0;
+			plist_get_real_val(node, &dval);
+			if ((float)dval == dval) {
+				float fval = (float)dval;
+				uint32_t u32val = 0;
+				memcpy(&u32val, &fval, 4);
+				u32val = float_bswap32(u32val);
+				uint8_t blen = 0x35;
+				char_buf_append(cbuf, 1, &blen);
+				char_buf_append(cbuf, 4, (unsigned char*)&u32val);
+			} else {
+				uint64_t u64val = 0;
+				memcpy(&u64val, &dval, 8);
+				u64val = float_bswap64(u64val);
+				uint8_t blen = 0x36;
+				char_buf_append(cbuf, 1, &blen);
+				char_buf_append(cbuf, 8, (unsigned char*)&u64val);
+			}
+		}	break;
+		case PLIST_DATE: {
+			int32_t sec = 0;
+			int32_t usec = 0;	
+			plist_get_date_val(node, &sec, &usec);
+			time_t tsec = sec;
+			tsec -= MAC_EPOCH;
+			double dval = (double)tsec + ((double)usec / 1000000);
+			uint8_t blen = 0x06;
+			char_buf_append(cbuf, 1, &blen);
+			uint64_t u64val = 0;
+			memcpy(&u64val, &dval, 8);
+			u64val = float_bswap64(u64val);
+			char_buf_append(cbuf, 8, (unsigned char*)&u64val);
+		}	break;
+		case PLIST_STRING:
+		case PLIST_KEY: {
+			uint64_t len = 0;
+			char* str = NULL;
+			if (type == PLIST_KEY) {
+				plist_get_key_val(node, &str);
+				len = strlen(str);
+			} else {
+				str = (char*)plist_get_string_ptr(node, &len);
+			}
+			if (len > 0x20) {
+				if (len > 0xFF) {
+					if (len > 0xFFFF) {
+						if (len >> 32) {
+							uint8_t blen = 0x64;
+							char_buf_append(cbuf, 1, &blen);
+							uint64_t u64val = htole64(len);
+							char_buf_append(cbuf, 8, (unsigned char*)&u64val);
+						} else {
+							uint8_t blen = 0x63;
+							char_buf_append(cbuf, 1, &blen);
+							uint32_t u32val = htole32((uint32_t)len);
+							char_buf_append(cbuf, 4, (unsigned char*)&u32val);
+						}
+					} else {
+						uint8_t blen = 0x62;
+						char_buf_append(cbuf, 1, &blen);
+						uint16_t u16val = htole16((uint16_t)len);
+						char_buf_append(cbuf, 2, (unsigned char*)&u16val);
+					}
+				} else {
+					uint8_t blen = 0x61;
+					char_buf_append(cbuf, 1, &blen);
+					char_buf_append(cbuf, 1, (unsigned char*)&len);
+				}
+			} else {
+				uint8_t blen = 0x40 + len;
+				char_buf_append(cbuf, 1, &blen);
+			}
+			char_buf_append(cbuf, len, (unsigned char*)str);
+			if (type == PLIST_KEY) {
+				free(str);
+			}
+		}	break;
+		case PLIST_DATA: {
+			uint64_t len = 0;
+			const char* data = plist_get_data_ptr(node, &len);
+			if (len > 0x20) {
+				if (len > 0xFF) {
+					if (len > 0xFFFF) {
+						if (len >> 32) {
+							uint8_t blen = 0x94;
+							char_buf_append(cbuf, 1, &blen);
+							uint32_t u64val = htole64(len);
+							char_buf_append(cbuf, 8, (unsigned char*)&u64val);
+						} else {
+							uint8_t blen = 0x93;
+							char_buf_append(cbuf, 1, &blen);
+							uint32_t u32val = htole32((uint32_t)len);
+							char_buf_append(cbuf, 4, (unsigned char*)&u32val);
+						}
+					} else {
+						uint8_t blen = 0x92;
+						char_buf_append(cbuf, 1, &blen);
+						uint16_t u16val = htole16((uint16_t)len);
+						char_buf_append(cbuf, 2, (unsigned char*)&u16val);
+					}
+				} else {
+					uint8_t blen = 0x91;
+					char_buf_append(cbuf, 1, &blen);
+					char_buf_append(cbuf, 1, (unsigned char*)&len);
+				}
+			} else {
+				uint8_t blen = 0x70 + len;
+				char_buf_append(cbuf, 1, &blen);
+			}
+			char_buf_append(cbuf, len, (unsigned char*)data);
+		}	break;
+		default:
+			fprintf(stderr, "%s: ERROR: Unsupported data type in plist\n", __func__);
+			break;
+	}
+}
+
+LIBIMOBILEDEVICE_GLUE_API void opack_encode_from_plist(plist_t plist, unsigned char** out, unsigned int* out_len)
+{
+	if (!plist || !out || !out_len) {
+		return;
+	}
+	struct char_buf* cbuf = char_buf_new();
+	opack_encode_node(plist, cbuf);
+	*out = cbuf->data;
+	*out_len = cbuf->length;
+	cbuf->data = NULL;
+	char_buf_free(cbuf);
+}
+
+static int opack_decode_obj(unsigned char** p, unsigned char* end, plist_t* plist_out, uint32_t level)
+{
+	uint8_t type = **p;
+	if (type == 0x02) {
+		/* bool: false */
+		*plist_out = plist_new_bool(0);
+		(*p)++;
+		return 0;
+	} else if (type == 0x01) {
+		/* bool: true */
+		*plist_out = plist_new_bool(1);
+		(*p)++;
+		return 0;
+	} else if (type == 0x03) {
+		/* NULL / structured type child node terminator */
+		(*p)++;
+		return -2;
+	} else if (type == 0x06) {
+		/* date type */
+		(*p)++;
+		double value = *(double*)*p;
+		time_t sec = (time_t)value;
+		value -= sec;
+		uint32_t usec = value * 1000000;
+		(*p)+=8;
+		*plist_out = plist_new_date(sec, usec);
+	} else if (type >= 0x08 && type <= 0x36) {
+		/* numerical type */
+		(*p)++;
+		uint64_t value = 0;
+		if (type == 0x36) {
+			/* double */
+			uint64_t u64val = float_bswap64(*(uint64_t*)(*p));
+			(*p)+=8;
+			double dval = 0;
+			memcpy(&dval, &u64val, 8);
+			*plist_out = plist_new_real(dval);
+			return 0;
+		} else if (type == 0x35) {
+			/* float */
+			uint32_t u32val = float_bswap32(*(uint32_t*)(*p));
+			(*p)+=4;
+			float fval = 0;
+			memcpy(&fval, &u32val, 4);
+			*plist_out = plist_new_real((double)fval);
+			return 0;
+		} else if (type < 0x30) {
+			value = type - 8;
+		} else if (type == 0x30) {
+			value = (int8_t)**p;
+			(*p)++;
+		} else if (type == 0x32) {
+			uint32_t u32val = *(uint32_t*)*p;
+			value = (int32_t)le32toh(u32val);
+			(p)+=4;
+		} else if (type == 0x33) {
+			uint64_t u64val = *(uint64_t*)*p;
+			value = le64toh(u64val);
+			(p)+=8;
+		} else {
+			fprintf(stderr, "%s: ERROR: Invalid encoded byte '%02x'\n", __func__, type);
+			*p = end;
+			return -1;
+		}
+		*plist_out = plist_new_uint(value);
+	} else if (type >= 0x40 && type <= 0x64) {
+		/* string */
+		(*p)++;
+		size_t slen = 0;
+		if (type < 0x61) {
+			slen = type - 0x40;
+		} else {
+			if (type == 0x61) {
+				slen = **p;
+				(*p)++;
+			} else if (type == 0x62) {
+				uint16_t u16val = *(uint16_t*)*p;
+				slen = le16toh(u16val);
+				(*p)+=2;
+			} else if (type == 0x63) {
+				uint32_t u32val = *(uint32_t*)*p;
+				slen = le32toh(u32val);
+				(*p)+=4;
+			} else if (type == 0x64) {
+				uint64_t u64val = *(uint64_t*)*p;
+				slen = le64toh(u64val);
+				(*p)+=8;
+			}
+		}
+		if (*p + slen > end) {
+			fprintf(stderr, "%s: ERROR: Size points past end of data\n", __func__);
+			*p = end;
+			return -1;
+		}
+		char* str = malloc(slen+1);
+		strncpy(str, (const char*)*p, slen);
+		str[slen] = '\0';
+		*plist_out = plist_new_string(str);
+		(*p)+=slen;
+		free(str);
+	} else if (type >= 0x70 && type <= 0x94) {
+		/* data */
+		(*p)++;
+		size_t dlen = 0;
+		if (type < 0x91) {
+			dlen = type - 0x70;
+		} else {
+			if (type == 0x91) {
+				dlen = **p;
+				(*p)++;
+			} else if (type == 0x92) {
+				uint16_t u16val = *(uint16_t*)*p;
+				dlen = le16toh(u16val);
+				(*p)+=2;
+			} else if (type == 0x93) {
+				uint32_t u32val = *(uint32_t*)*p;
+				dlen = le32toh(u32val);
+				(*p)+=4;
+			} else if (type == 0x94) {
+				uint64_t u64val = *(uint64_t*)*p;
+				dlen = le64toh(u64val);
+				(*p)+=8;
+			}
+		}
+		if (*p + dlen > end) {
+			fprintf(stderr, "%s: ERROR: Size points past end of data\n", __func__);
+			*p = end;
+			return -1;
+		}
+		*plist_out = plist_new_data((const char*)*p, dlen);
+		(*p)+=dlen;
+	} else if (type >= 0xE0 && type <= 0xEF) {
+		/* dictionary */
+		(*p)++;
+		plist_t dict = plist_new_dict();
+		uint32_t num_children = 0xFFFFFFFF;
+		if (type < 0xEF) {
+			/* explicit number of children */
+			num_children = type - 0xE0;
+		}
+		if (!*plist_out) {
+			*plist_out = dict;	
+		}
+		uint32_t i = 0;
+		while (i++ < num_children) {
+			plist_t keynode = NULL;
+			int res = opack_decode_obj(p, end, &keynode, level+1);
+			if (res == -2) {
+				break;
+			} else if (res < 0) {
+				return -1;
+			}
+			if (!PLIST_IS_STRING(keynode)) {
+				plist_free(keynode);
+				fprintf(stderr, "%s: ERROR: Invalid node type for dictionary key node\n", __func__);
+				*p = end;
+				return -1;
+			}
+			char* key = NULL;
+			plist_get_string_val(keynode, &key);
+			plist_free(keynode);
+			plist_t valnode = NULL;
+			if (opack_decode_obj(p, end, &valnode, level+1) < 0) {
+				free(key);
+				return -1;
+			}
+			plist_dict_set_item(dict, key, valnode);
+		}
+		if (level == 0) {
+			*p = end;
+			return 0;
+		}
+	} else if (type >= 0xD0 && type <= 0xDF) {
+		/* array */
+		(*p)++;
+		plist_t array = plist_new_array();
+		if (!*plist_out) {
+			*plist_out = array;
+		}
+		uint32_t num_children = 0xFFFFFFFF;
+		if (type < 0xDF) {
+			/* explicit number of children */
+			num_children = type - 0xD0;
+		}
+		uint32_t i = 0;
+		while (i++ < num_children) {
+			plist_t child = NULL;
+			int res = opack_decode_obj(p, end, &child, level+1);
+			if (res == -2) {
+				if (type < 0xDF) {
+					fprintf(stderr, "%s: ERROR: Expected child node, found terminator\n", __func__);
+					*p = end;
+					return -1;
+				}
+				break;
+			} else if (res < 0) {
+				return -1;
+			}
+			plist_array_append_item(array, child);
+		}
+		if (level == 0) {
+			*p = end;
+			return 0;
+		}
+	} else {
+		fprintf(stderr, "%s: ERROR: Unexpected character '%02x encountered\n", __func__, type);
+		*p = end;
+		return -1;
+	}
+	return 0;
+}
+
+LIBIMOBILEDEVICE_GLUE_API int opack_decode_to_plist(unsigned char* buf, unsigned int buf_len, plist_t* plist_out)
+{
+	if (!buf || buf_len == 0 || !plist_out) {
+		return -1;
+	}
+	unsigned char* p = buf;
+	unsigned char* end = buf + buf_len;
+	while (p < end) {
+		opack_decode_obj(&p, end, plist_out, 0);
+	}
+	return 0;
+}