// Copyright (c) Microsoft. All rights reserved. // Licensed under the MIT license. See LICENSE file in the project root for full license information. #include #include #include #include "azure_c_shared_utility/buffer_.h" #include "azure_c_shared_utility/xlogging.h" #include "azure_c_shared_utility/gballoc.h" #include "azure_c_shared_utility/strings.h" #include "azure_c_shared_utility/safe_math.h" #include "azure_c_shared_utility/azure_base32.h" static const unsigned char BASE32_EQUAL_SIGN = 32; static const char BASE32_VALUES[] = "abcdefghijklmnopqrstuvwxyz234567="; #define TARGET_BLOCK_SIZE 5 #define INVALID_CHAR_POS 260 #define BASE32_INPUT_SIZE 8 #define ASCII_VALUE_MAX 0x80 static size_t base32_encoding_length(size_t src_len) { return (((src_len + TARGET_BLOCK_SIZE - 1) / TARGET_BLOCK_SIZE) * 8); } static size_t base32_decoding_length(size_t src_len) { return ((src_len*TARGET_BLOCK_SIZE) / 8); } static unsigned char convert_value_to_base32_char(unsigned char value) { unsigned char result; if (value >= 50 && value <= 55) { result = 0x1a+(value-50); } else if (value == 61) { result = 0x20; } else if ((value <= 49) || (value >= 56 && value <= 64)) { result = 0xFF; } else if (value >= 65 && value <= 90) { result = 0x00 + (value - 65); } else if (value >= 91 && value <= 96) { result = 0xFF; } else if (value >= 97 && value <= 123) { result = 0x00 + (value - 97); } else // value > 123 { result = 0xFF; } return result; } static char* base32_encode_impl(const unsigned char* source, size_t src_size) { char* result; // Allocate target buffer size_t output_len = safe_add_size_t(base32_encoding_length(src_size), 1); if (output_len == SIZE_MAX) { result = NULL; LogError("invalid src_size"); } /* Codes_SRS_BASE32_07_009: [ base32_encode_impl shall allocate the buffer to the size of the encoding value. ] */ else if ((result = (char*)malloc(output_len)) == NULL) { LogError("Failure allocating output buffer"); } else { const unsigned char* iterator = source; size_t block_len = 0; size_t result_len = 0; unsigned char pos1 = 0; unsigned char pos2 = 0; unsigned char pos3 = 0; unsigned char pos4 = 0; unsigned char pos5 = 0; unsigned char pos6 = 0; unsigned char pos7 = 0; unsigned char pos8 = 0; memset(result, 0, output_len); // Go through the source buffer sectioning off blocks of 5 /* Codes_SRS_BASE32_07_010: [ base32_encode_impl shall look through source and separate each block into 5 bit chunks ] */ while (src_size >= 1) { pos1 = pos2 = pos3 = pos4 = pos5 = pos6 = pos7 = pos8 = 0; block_len = src_size > TARGET_BLOCK_SIZE ? TARGET_BLOCK_SIZE : src_size; // Fall through switch block to process the 5 (or smaller) block switch (block_len) { case 5: pos8 = (iterator[4] & 0x1f); pos7 = ((iterator[4] & 0xe0) >> 5); // fall through case 4: pos7 |= ((iterator[3] & 0x03) << 3); pos6 = ((iterator[3] & 0x7c) >> 2); pos5 = ((iterator[3] & 0x80) >> 7); // fall through case 3: pos5 |= ((iterator[2] & 0x0f) << 1); pos4 = ((iterator[2] & 0xf0) >> 4); // fall through case 2: pos4 |= ((iterator[1] & 0x01) << 4); pos3 = ((iterator[1] & 0x3e) >> 1); pos2 = ((iterator[1] & 0xc0) >> 6); // fall through case 1: pos2 |= ((iterator[0] & 0x07) << 2); pos1 = ((iterator[0] & 0xf8) >> 3); break; } // Move the iterator the block size iterator += block_len; // and decrement the src_size; src_size -= block_len; /* Codes_SRS_BASE32_07_012: [ If the src_size is not divisible by 8, base32_encode_impl shall pad the remaining places with =. ] */ switch (block_len) { case 1: pos3 = pos4 = 32; // fall through case 2: pos5 = 32; // fall through case 3: pos6 = pos7 = 32; // fall through case 4: pos8 = 32; // fall through case 5: break; } if ((result_len + 8) > output_len) { LogError("result buffer is too small"); free(result); result = NULL; break; } /* Codes_SRS_BASE32_07_011: [ base32_encode_impl shall then map the 5 bit chunks into one of the BASE32 values (a-z,2,3,4,5,6,7) values. ] */ result[result_len++] = BASE32_VALUES[pos1]; result[result_len++] = BASE32_VALUES[pos2]; result[result_len++] = BASE32_VALUES[pos3]; result[result_len++] = BASE32_VALUES[pos4]; result[result_len++] = BASE32_VALUES[pos5]; result[result_len++] = BASE32_VALUES[pos6]; result[result_len++] = BASE32_VALUES[pos7]; result[result_len++] = BASE32_VALUES[pos8]; } } return result; } static BUFFER_HANDLE base32_decode_impl(const char* source) { BUFFER_HANDLE result; size_t src_length = strlen(source); if (src_length % BASE32_INPUT_SIZE != 0) { /* Codes_SRS_BASE32_07_021: [ If the source length is not evenly divisible by 8, base32_decode_impl shall return NULL. ] */ LogError("Failure invalid input length %lu", (unsigned long)src_length); result = NULL; } else { size_t dest_size = 0; unsigned char* temp_buffer; unsigned char* dest_buff; bool continue_processing = true; unsigned char input[8]; const char* iterator = source; /* Codes_SRS_BASE32_07_022: [ base32_decode_impl shall allocate a temp buffer to store the in process value. ] */ size_t allocation_len = base32_decoding_length(src_length); if ((temp_buffer = (unsigned char*)malloc(allocation_len)) == NULL) { /* Codes_SRS_BASE32_07_023: [ If an error is encountered, base32_decode_impl shall return NULL. ] */ LogError("Failure allocating buffer"); result = NULL; } else { dest_buff = temp_buffer; while (*iterator != '\0') { size_t index = 0; /* Codes_SRS_BASE32_07_024: [ base32_decode_impl shall loop through and collect 8 characters from the source variable. ] */ for (index = 0; index < BASE32_INPUT_SIZE; index++) { input[index] = *iterator; iterator++; if (input[index] >= ASCII_VALUE_MAX) { LogError("Failure source encoding"); continue_processing = false; break; } input[index] = convert_value_to_base32_char(input[index]); } if (!continue_processing) { result = NULL; break; } else if ((dest_size + TARGET_BLOCK_SIZE) > allocation_len) { LogError("Failure target length exceeded"); result = NULL; continue_processing = false; break; } else { // Codes_SRS_BASE32_07_025: [ base32_decode_impl shall group 5 bytes at a time into the temp buffer. ] *dest_buff++ = ((input[0] & 0x1f) << 3) | ((input[1] & 0x1c) >> 2); *dest_buff++ = ((input[1] & 0x03) << 6) | ((input[2] & 0x1f) << 1) | ((input[3] & 0x10) >> 4); *dest_buff++ = ((input[3] & 0x0f) << 4) | ((input[4] & 0x1e) >> 1); *dest_buff++ = ((input[4] & 0x01) << 7) | ((input[5] & 0x1f) << 2) | ((input[6] & 0x18) >> 3); *dest_buff++ = ((input[6] & 0x07) << 5) | (input[7] & 0x1f); dest_size += TARGET_BLOCK_SIZE; // If there is padding remove it // Because we are packing 5 bytes into an 8 byte variable we need to check every other // variable for padding if (input[7] == BASE32_EQUAL_SIGN) { --dest_size; if (input[5] == BASE32_EQUAL_SIGN) { --dest_size; if (input[4] == BASE32_EQUAL_SIGN) { --dest_size; if (input[2] == BASE32_EQUAL_SIGN) { --dest_size; } } } } } } if (!continue_processing) { result = NULL; } else { /* Codes_SRS_BASE32_07_026: [ Once base32_decode_impl is complete it shall create a BUFFER with the temp buffer. ] */ result = BUFFER_create(temp_buffer, dest_size); if (result == NULL) { LogError("Failure: BUFFER_create failed to create decoded buffer"); } } free(temp_buffer); } } return result; } BUFFER_HANDLE Azure_Base32_Decode(STRING_HANDLE handle) { BUFFER_HANDLE result; if (handle == NULL) { /* Codes_SRS_BASE32_07_016: [ If source is NULL Azure_Base32_Decode shall return NULL. ] */ LogError("invalid parameter handle"); result = NULL; } else { const char* str_source = STRING_c_str(handle); if (str_source == NULL) { /* Codes_SRS_BASE32_07_027: [ If the string in source value is NULL, Azure_Base32_Decode shall return NULL. ] */ LogError("NULL value specified in string"); result = NULL; } else { /* Codes_SRS_BASE32_07_018: [ Azure_Base32_Decode shall call base32_decode_impl to decode the base64 value. ] */ result = base32_decode_impl(str_source); } } /* Codes_SRS_BASE32_07_017: [ On success Azure_Base32_Decode shall return a BUFFER_HANDLE that contains the decoded bytes for source. ] */ return result; } BUFFER_HANDLE Azure_Base32_Decode_String(const char* source) { BUFFER_HANDLE result; if (source == NULL) { /* Codes_SRS_BASE32_07_008: [ If source is NULL Azure_Base32_Decode_String shall return NULL. ] */ LogError("invalid parameter source=NULL"); result = NULL; } else { /* Codes_SRS_BASE32_07_020: [ Azure_Base32_Decode_String shall call base32_decode_impl to decode the base64 value. ] */ result = base32_decode_impl(source); } /* Codes_SRS_BASE32_07_019: [ On success Azure_Base32_Decode_String shall return a BUFFER_HANDLE that contains the decoded bytes for source. ] */ return result; } char* Azure_Base32_Encode_Bytes(const unsigned char* source, size_t size) { char* result; if (source == NULL) { /* Codes_SRS_BASE32_07_004: [ If source is NULL Azure_Base32_Encode_Bytes shall return NULL. ] */ result = NULL; LogError("Failure: Invalid input parameter source"); } else if (size == 0) { /* Codes_SRS_BASE32_07_005: [ If size is 0 Azure_Base32_Encode_Bytes shall return an empty string. ] */ if ((result = malloc(1)) != NULL) { strcpy(result, ""); } else { LogError("unable to allocate memory for result"); } } else { /* Codes_SRS_BASE32_07_007: [ Azure_Base32_Encode_Bytes shall call into base32_Encode_impl to encode the source data. ] */ result = base32_encode_impl(source, size); if (result == NULL) { /* Codes_SRS_BASE32_07_014: [ Upon failure Azure_Base32_Encode_Bytes shall return NULL. ] */ LogError("encoding of unsigned char failed."); } } /* Codes_SRS_BASE32_07_006: [ If successful Azure_Base32_Encode_Bytes shall return the base32 value of input. ] */ return result; } STRING_HANDLE Azure_Base32_Encode(BUFFER_HANDLE source) { STRING_HANDLE result; if (source == NULL) { /* Codes_SRS_BASE32_07_001: [ If source is NULL Azure_Base32_Encode shall return NULL. ] */ result = NULL; LogError("Failure: Invalid input parameter"); } else { size_t input_len = BUFFER_length(source); const unsigned char* input_value = BUFFER_u_char(source); if (input_value == NULL || input_len == 0) { /* Codes_SRS_BASE32_07_015: [ If size is 0 Azure_Base32_Encode shall return an empty string. ] */ result = STRING_new(); if (result == NULL) { LogError("Failure constructing new string."); } } else { /* Codes_SRS_BASE32_07_003: [ Azure_Base32_Encode shall call into base32_Encode_impl to encode the source data. ] */ char* encoded = base32_encode_impl(input_value, input_len); if (encoded == NULL) { /* Codes_SRS_BASE32_07_014: [ Upon failure Azure_Base32_Encode shall return NULL. ] */ LogError("base32 encode implementation failed."); result = NULL; } else { /* Codes_SRS_BASE32_07_012: [ Azure_Base32_Encode shall wrap the base32_Encode_impl result into a STRING_HANDLE. ] */ result = STRING_construct(encoded); if (result == NULL) { /* Codes_SRS_BASE32_07_014: [ Upon failure Azure_Base32_Encode shall return NULL. ] */ LogError("string construction failed."); } free(encoded); } } } /* Codes_SRS_BASE32_07_002: [ If successful Azure_Base32_Encode shall return the base32 value of source. ] */ return result; }