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Code Releases Wiki Activity

Fossil Hybrid: dynmically generate check byte

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This commit is contained in:
Daniel Dakhno 2020-10-31 12:40:20 +01:00
parent d8ade53cdf
commit e8534e01f8
1 changed files with 10 additions and 4 deletions
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14
app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/qhybrid/requests/fossil_hr/file/FileEncryptedGetRequest.java
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@ -56,6 +56,8 @@ public abstract class FileEncryptedGetRequest extends FossilRequest {
private SecretKeySpec keySpec;
private byte[] originalIv;
int fileSize;
private int packetCount = 0;
private int ivIncrementor = 0x1f;
@ -133,7 +135,7 @@ public abstract class FileEncryptedGetRequest extends FossilRequest {
this.initDecryption();
short handle = buffer.getShort(1);
int size = buffer.getInt(4);
fileSize = buffer.getInt(4);
byte status = buffer.get(3);
@ -145,8 +147,8 @@ public abstract class FileEncryptedGetRequest extends FossilRequest {
if (this.handle != handle) {
throw new RuntimeException("handle: " + handle + " expected: " + this.handle);
}
log("file size: " + size);
fileBuffer = ByteBuffer.allocate(size);
log("file size: " + fileSize);
fileBuffer = ByteBuffer.allocate(fileSize);
} else if ((first & 0x0F) == 8) {
this.finished = true;
@ -181,7 +183,11 @@ public abstract class FileEncryptedGetRequest extends FossilRequest {
cipher.init(Cipher.DECRYPT_MODE, keySpec, new IvParameterSpec(iv));
result = cipher.doFinal(value);
if(result[0] == 0x01 || result[0] == 0x81){
int currentLength = fileBuffer.position() + result.length - 1;
byte expectedByte = (currentLength == fileSize) ? (byte)0x81 : (byte)0x01; // 0x81 indicated the last payload
if(result[0] == expectedByte){
this.ivIncrementor = testIvSummand;
log("iv summand: " + testIvSummand);
break;