GitHub/dsd-fme
1
0
Fork 0
mirror of https://github.com/lwvmobile/dsd-fme.git synced 2026-11-11 16:27:24 -05:00
Code Issues Packages Projects Releases Wiki Activity

DMR: Tidy Up PDU Enc Code;

Browse Source
This commit is contained in:
lwvmobile
2025-03-03 23:09:02 -05:00
parent 4255a2f9ba
commit eebb251d2f
1 changed files with 12 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
src/dmr_block.c
View File

@@ -890,12 +890,12 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
#ifdef DMR_PDU_DECRYPTION
if (enc_check)
{
// decrypted_pdu = 0; //hasn't been decrypted yet
int poc = (int)state->data_block_poc[slot]; //say that three times real fast
int poc = (int)state->data_block_poc[slot];
int start = (int)state->data_ks_start[slot];
int end = ((blocks+1)*block_len)-4-poc-start;
//sanity check on end, has to be a positive value
if (end < 0) end = 3096; //its a signed interger, so should reflect negative values here and not rollover
if (end < 0) end = 3096;
int alg = 0;
int kid = 0;
if (state->currentslot == 0)
@@ -907,21 +907,20 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
else kid = state->payload_keyidR;
//start keystream creation
uint8_t ob[129*24]; //may need more blocks (enough for 127 * 24)
uint8_t kiv[9]; UNUSED(kiv);
uint8_t ob[129*24];
uint8_t kiv[9];
uint32_t mi = 0;
unsigned long long int R = 0;
if (state->currentslot == 0)
mi = (uint32_t)state->payload_mi;
else mi = (uint32_t)state->payload_miR;
//mini key loader for RC4/DES
//key loader
if (state->currentslot == 0)
R = state->rkey_array[state->payload_keyid];
else
R = state->rkey_array[state->payload_keyidR];
if (R == 0 && state->R != 0) R = state->R;
//easier to manually load up rather than make a loop (RC4)
@@ -953,18 +952,15 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
//NOTE: Observed that keystream should not be applied to pad bytes or CRC
//apply keystream here, only if alg is 1 or 4 AND key is available!
//using modulus 3096 to prevent sefgault (increased storage and changed ofb modes to a ptr)
//will want to rework output_blocks to be a pointer instead of a fixed size (done)
if (alg == 1 && R != 0)
{
for (i = 0; i < end; i++)
state->dmr_pdu_sf[slot][i+start] ^= ob[i%3096];
}
//BP key application
else if (alg == 0) //&& state->K != 0
{
//NOTE: using dmr_sr and dmr_soR now for a enc check on all encrypted PDUs
//BP key application
else if (alg == 0)
{
uint16_t bp_key = 0;
if (state->K != 0) //state->M == 1 &&
{
@@ -972,22 +968,19 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
bp_key = BPK[state->K];
ob[0] = (bp_key >> 8) & 0xFF;
ob[1] = (bp_key >> 0) & 0xFF;
//
fprintf (stderr, " Key: %lld:%04X;", state->K, bp_key);
// fprintf (stderr, "ob1: %02X; ob2: %02X", ob[0], ob[1]);
fprintf (stderr, " Key: %lld : %04X;", state->K, bp_key);
}
if (bp_key != 0)
{
for (i = start; i < (end-start); i++)
state->dmr_pdu_sf[slot][i] ^= ob[i%2]; //modulus 2 here, just rinse and repeat
state->dmr_pdu_sf[slot][i] ^= ob[i%2];
decrypted_pdu = 1;
}
}
//reset alg/keyid/mi after running?
//reset alg/keyid/mi
if (state->currentslot == 0)
{
state->payload_mi = 0;