mirror of
https://github.com/d0k3/GodMode9.git
synced 2025-06-26 13:42:47 +00:00
74 lines
2.5 KiB
C
74 lines
2.5 KiB
C
#include "ncsd.h"
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#include "ncch.h"
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u32 ValidateNcsdHeader(NcsdHeader* header) {
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u8 zeroes[16] = { 0 };
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if ((memcmp(header->magic, "NCSD", 4) != 0) || // check magic number
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(memcmp(header->partitions_fs_type, zeroes, 8) != 0) || !header->mediaId) // prevent detection of NAND images
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return 1;
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u32 data_units = 0;
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for (u32 i = 0; i < 8; i++) {
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NcchPartition* partition = header->partitions + i;
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if ((i == 0) && !partition->size) return 1; // first content must be there
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else if (!partition->size) continue;
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if (partition->offset < data_units)
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return 1; // overlapping partitions, failed
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data_units = partition->offset + partition->size;
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}
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if (data_units > header->size)
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return 1;
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return 0;
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}
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u64 GetNcsdTrimmedSize(NcsdHeader* header) {
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u32 data_units = 0;
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for (u32 i = 0; i < 8; i++) {
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NcchPartition* partition = header->partitions + i;
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u32 partition_end = partition->offset + partition->size;
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if (!partition->size) continue;
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data_units = (partition_end > data_units) ? partition_end : data_units;
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}
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return data_units * NCSD_MEDIA_UNIT;
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}
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// on the fly decryptor for NCSD
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u32 CryptNcsdSequential(u8* data, u32 offset_data, u32 size_data, u16 crypto) {
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// warning: this will only work for sequential processing
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static NcsdHeader ncsd;
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// fetch ncsd header from data
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if ((offset_data == 0) && (size_data >= sizeof(NcsdHeader)))
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memcpy(&ncsd, data, sizeof(NcsdHeader));
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for (u32 i = 0; i < 8; i++) {
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NcchPartition* partition = ncsd.partitions + i;
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u32 offset_p = partition->offset * NCSD_MEDIA_UNIT;
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u32 size_p = partition->size * NCSD_MEDIA_UNIT;
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// check if partition in data
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if ((offset_p >= offset_data + size_data) ||
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(offset_data >= offset_p + size_p) ||
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!size_p) {
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continue; // section not in data
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}
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// determine data / offset / size
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u8* data_i = data;
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u32 offset_i = 0;
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u32 size_i = size_p;
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if (offset_p < offset_data)
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offset_i = offset_data - offset_p;
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else data_i = data + (offset_p - offset_data);
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size_i = size_p - offset_i;
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if (size_i > size_data - (data_i - data))
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size_i = size_data - (data_i - data);
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// decrypt ncch segment
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if (CryptNcchSequential(data_i, offset_i, size_i, crypto) != 0)
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return 1;
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}
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return 0;
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}
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