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authorGravatar Nikias Bassen2022-02-04 04:21:28 +0100
committerGravatar Nikias Bassen2022-02-04 04:21:28 +0100
commit90fc3833203192ff5a6009d339454b0265b4efc1 (patch)
tree36d43304d2849063b4549441eab38f53043cb5b9 /src/tlv.c
parentb5ccf24362f65cacc96f529c33bd2dcf2a50cf1b (diff)
downloadlibimobiledevice-glue-90fc3833203192ff5a6009d339454b0265b4efc1.tar.gz
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Add support for Apple's OPACK encoding and TLV format
Diffstat (limited to 'src/tlv.c')
-rw-r--r--src/tlv.c196
1 files changed, 196 insertions, 0 deletions
diff --git a/src/tlv.c b/src/tlv.c
new file mode 100644
index 0000000..d08c8f3
--- /dev/null
+++ b/src/tlv.c
@@ -0,0 +1,196 @@
+/*
+ * tlv.c
+ * Simple TLV 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/tlv.h"
+#include "endianness.h"
+
+LIBIMOBILEDEVICE_GLUE_API tlv_buf_t tlv_buf_new()
+{
+ tlv_buf_t tlv = malloc(sizeof(struct tlv_buf));
+ tlv->capacity = 1024;
+ tlv->length = 0;
+ tlv->data = malloc(tlv->capacity);
+ return tlv;
+}
+
+LIBIMOBILEDEVICE_GLUE_API void tlv_buf_free(tlv_buf_t tlv)
+{
+ if (tlv) {
+ free(tlv->data);
+ free(tlv);
+ }
+}
+
+LIBIMOBILEDEVICE_GLUE_API void tlv_buf_append(tlv_buf_t tlv, uint8_t tag, unsigned int length, void* data)
+{
+ if (!tlv || !tlv->data) {
+ return;
+ }
+ unsigned int req_len = (length > 255) ? (length / 255) * 257 + (2 + (length % 255)) : length;
+ if (tlv->length + req_len > tlv->capacity) {
+ unsigned int newcapacity = tlv->capacity + ((req_len / 1024) + 1) * 1024;
+ unsigned char* newdata = realloc(tlv->data, newcapacity);
+ if (!newdata) {
+ fprintf(stderr, "%s: ERROR: Failed to realloc\n", __func__);
+ return;
+ }
+ tlv->data = newdata;
+ tlv->capacity = newcapacity;
+ }
+ unsigned char* p = tlv->data + tlv->length;
+ unsigned int cur = 0;
+ while (length - cur > 0) {
+ if (length - cur > 255) {
+ *(p++) = tag;
+ *(p++) = 0xFF;
+ memcpy(p, (unsigned char*)data + cur, 255);
+ p += 255;
+ cur += 255;
+ } else {
+ uint8_t rem = length - cur;
+ *(p++) = tag;
+ *(p++) = rem;
+ memcpy(p, (unsigned char*)data + cur, rem);
+ p += rem;
+ cur += rem;
+ }
+ }
+ tlv->length = p - tlv->data;
+}
+
+LIBIMOBILEDEVICE_GLUE_API unsigned char* tlv_get_data_ptr(const void* tlv_data, void* tlv_end, uint8_t tag, uint8_t* length)
+{
+ unsigned char* p = (unsigned char*)tlv_data;
+ unsigned char* end = (unsigned char*)tlv_end;
+ while (p < end) {
+ uint8_t cur_tag = *(p++);
+ uint8_t len = *(p++);
+ if (cur_tag == tag) {
+ *length = len;
+ return p;
+ }
+ p+=len;
+ }
+ return NULL;
+}
+
+LIBIMOBILEDEVICE_GLUE_API int tlv_data_get_uint(const void* tlv_data, unsigned int tlv_length, uint8_t tag, uint64_t* value)
+{
+ if (!tlv_data || tlv_length < 2 || !value) {
+ return 0;
+ }
+ uint8_t length = 0;
+ unsigned char* ptr = tlv_get_data_ptr(tlv_data, (unsigned char*)tlv_data+tlv_length, tag, &length);
+ if (!ptr) {
+ return 0;
+ }
+ if (ptr + length > (unsigned char*)tlv_data + tlv_length) {
+ return 0;
+ }
+ if (length == 1) {
+ uint8_t val = *ptr;
+ *value = val;
+ } else if (length == 2) {
+ uint16_t val = *(uint16_t*)ptr;
+ val = le16toh(val);
+ *value = val;
+ } else if (length == 4) {
+ uint32_t val = *(uint32_t*)ptr;
+ val = le32toh(val);
+ *value = val;
+ } else if (length == 8) {
+ uint64_t val = *(uint64_t*)ptr;
+ val = le64toh(val);
+ *value = val;
+ } else {
+ return 0;
+ }
+ return 1;
+}
+
+LIBIMOBILEDEVICE_GLUE_API int tlv_data_get_uint8(const void* tlv_data, unsigned int tlv_length, uint8_t tag, uint8_t* value)
+{
+ if (!tlv_data || tlv_length < 2 || !value) {
+ return 0;
+ }
+ uint8_t length = 0;
+ unsigned char* ptr = tlv_get_data_ptr(tlv_data, (unsigned char*)tlv_data+tlv_length, tag, &length);
+ if (!ptr) {
+ return 0;
+ }
+ if (length != 1) {
+ return 0;
+ }
+ if (ptr + length > (unsigned char*)tlv_data + tlv_length) {
+ return 0;
+ }
+ *value = *ptr;
+ return 1;
+}
+
+LIBIMOBILEDEVICE_GLUE_API int tlv_data_copy_data(const void* tlv_data, unsigned int tlv_length, uint8_t tag, void** out, unsigned int* out_len)
+{
+ if (!tlv_data || tlv_length < 2 || !out || !out_len) {
+ return 0;
+ }
+ *out = NULL;
+ *out_len = 0;
+
+ unsigned char* dest = NULL;
+ unsigned int dest_len = 0;
+
+ unsigned char* ptr = (unsigned char*)tlv_data;
+ unsigned char* end = (unsigned char*)tlv_data + tlv_length;
+ while (ptr < end) {
+ uint8_t length = 0;
+ ptr = tlv_get_data_ptr(ptr, end, tag, &length);
+ if (!ptr) {
+ break;
+ }
+ unsigned char* newdest = realloc(dest, dest_len + length);
+ if (!newdest) {
+ free(dest);
+ return 0;
+ }
+ dest = newdest;
+ memcpy(dest + dest_len, ptr, length);
+ dest_len += length;
+ ptr += length;
+ }
+ if (!dest) {
+ return 0;
+ }
+
+ *out = (void*)dest;
+ *out_len = dest_len;
+
+ return 1;
+}