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sunny-shu avatar sunny-shu commented on May 23, 2024 1

I was reading the source code of winrar and now I found some important clues. I think in a few days, I can solve this issue.

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sunny-shu avatar sunny-shu commented on May 23, 2024

yeah，i agree with you.
When i was doing this feature，i thougt i shoud creat a filterinputStream to support decryption.
but if i do so, more changes come up.and DataComprIO is just a wrapper of channel and DataComprIO assume this role。
so i have not created a new class.

when support to decrypt encrypted archives,Let's refactor again。

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gotson avatar gotson commented on May 23, 2024

i was playing with the code this morning, trying to decrypt the headers. The most painful part is that AES/CBC is a block cipher, and it requires decrypting by block of 16 bytes. That's what the read code in ComprDataIO is doing at the moment.

I like the FilterInputStream idea, but we don't always use a stream, as the channel can be a file or stream, and we have very low level operations reading byte[].

I'm trying to have a working decryption of the headers first, even with dirty code, then we can refactor.

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sunny-shu avatar sunny-shu commented on May 23, 2024

@gotson
do you work it out?

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gotson avatar gotson commented on May 23, 2024

Nope. I'm confident the salt is the next 8 bytes after the main header, I could get some data decrypted but the size is wrong and I get an extraction error.

I didn't have time to debug more.

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sunny-shu avatar sunny-shu commented on May 23, 2024

If you don’t have time, I will continue your work。

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gotson avatar gotson commented on May 23, 2024

@sunny-shu sure. I have pushed a branch encrypted-headers with my current work, you can use that.

I think we need to implement the same behaviour as in ComprDataIO with the decryptedDataBuffer and notConsumptedLen. Because the Archive.readHeaders() method reads headers in small parts, and we need to decrypt in blocks of 16 bytes with AES.

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sunny-shu avatar sunny-shu commented on May 23, 2024

@sunny-shu i think i have found where the salt for the header encryption is located. I have found this website that talk about it (it's in french). The 8 byte salt is located just after the Main Header block. They also have working python code for decryption which confirms the location of the salt.

hi gotson,have you tested the project "unarcrypto"?
i test it with header-encrypted file and fail.

here is the log.

python3 test.py -p test test1.rar

password= test
Block header: crc 6152 type 72 (marker) flags 0x1a21 size 7 addsize 0
Block header: crc 99ce type 73 (archive) flags 0x80 size 13 addsize 0
headersEncrypted True
header salt b'acbbc8f5d6a50a48'
password test
iv b'e2b62aedef183ba788553e597d2dea30' key b'0347c2184752bd449d39302dc76347f2'
encrypted headers: AES key is OK
Block header: crc a32d type 74 (file) flags 0x9624 size 79 addsize 0
has password
has ext_time
file salt b'acbbc8f5d6a50a48'
file crc OK ? False
header salt b'acbbc8f5d6a50a48'
password test
iv b'e2b62aedef183ba788553e597d2dea30' key b'0347c2184752bd449d39302dc76347f2'
encrypted headers: AES key is OK
Block header: crc 3dc4 type 7b (terminator) flags 0x4000 size 7 addsize 0

i must make sure the project can get right result before i can refer to his code.

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gotson avatar gotson commented on May 23, 2024

Why do you say it fails?

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sunny-shu avatar sunny-shu commented on May 23, 2024

file crc OK ? False

I know better about compression。
Decompression is a mathematical calculation. If input data is wrong, the decompression can stiil continue, but the result is wrong。
the log shows the content is wrong.

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gotson avatar gotson commented on May 23, 2024

Indeed.

It seems it's OK for RAR5 though:

> python3 unarcrypto.py -p hello -s 76d7a5a8d72da80c19acbd0f20f90dabac0c52f6 -v 1 tests/hello5_pw_store.rar                                    7.7s  Wed Jul 29 02:50:01 2020
password= hello
Block header: crc e5b59233 headerSize 10 headerType 1 (Main) headerFlags 5
  ARCHIVE_FLAG_VOLUME
  ARCHIVE_FLAG_SOLID
  extraSize 6 archiveFlags 0 volNum -1
  extra: b'050101808000'
  innerExtraSize 5 extraType 1 extraData: b'0101808000'
Block header: crc d5c0a057 headerSize 86 headerType 2 (File) headerFlags 3
  extraSize 60 fileFlags 4 dataSize 32 unpackedSize 23 dataCRC 0x292f7419 comprInfo 0x0 hostOS 0 filename b'hello.txt'
  innerExtraSize 48 extraType 1 (Encryption) extraData: b'00030f3e8ecf5188a0ceae32cc0fdfc9ab9980825952411445b8610ccbe6b3eb05b81591179e35245a115c37811683'
    encrVersion 0 encrFlags 3 kdfCount 15 salt b'3e8ecf5188a0ceae32cc0fdfc9ab9980' iv b'825952411445b8610ccbe6b3eb05b815' checkValue b'91179e35245a115c37811683'
    use tweaked checksum
  innerExtraSize 10 extraType 3 (Time) extraData: b'02bf2b20ff1e13d201'
    winFileTime b'bf2b20ff1e13d201'
  hmac_sha256(password,hashdata) b'de1bf4c31403ca43d8538b4a0fb34fa3c67feffd74b7e2fd507e82b88cc22b74'
  AES key b'a9356e422f3d7fcd8a9b851697cda8d96e6741e46a5e443b490dfb8a4ddcee52'
  v1 b'358eb01bed0cc6d9e6c4f8fef1b02adf173215e59325f70c788d46bc5b678464'
  v2 b'447751b5b3a8d51651d60e7ed36beb70ed0dc8e985a1f6c869bb0917c138d9f2'
  passwd check OK ? True , hash value OK ? True
  sha1 correct ? True
Block header: crc 5156771d headerSize 3 headerType 5 (End) headerFlags 4

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gotson avatar gotson commented on May 23, 2024

I have tested other archives in the test folder, some are working.

> python3 unarcrypto.py -p hello -v 1 tests/hello_pw_store_encryptednames2.rar                                                            330ms  Wed Jul 29 02:53:52 2020
password= hello
Block header: crc 6152 type 72 (marker) flags 0x1a21 size 7  addsize 0
Block header: crc 99ce type 73 (archive) flags 0x80 size 13  addsize 0
  headersEncrypted True
header salt b'86d6dabf466195dc'
iv b'223bcf9b6ad1c376047622108bfdf05c' key b'4c17206f78c6ccd81de9d8998895740d'
encrypted headers: AES key is OK
Block header: crc 6f5 type 74 (file) flags 0x9424 size 54  addsize 0
  has password
  has ext_time
  file salt b'86d6dabf466195dc'
  file crc OK ?  True
header salt b'86d6dabf466195dc'
iv b'223bcf9b6ad1c376047622108bfdf05c' key b'4c17206f78c6ccd81de9d8998895740d'
encrypted headers: AES key is OK
Block header: crc 3dc4 type 7b (terminator) flags 0x4000 size 7  addsize 0

> python3 unarcrypto.py -p hello -v 1 tests/hello_pw_store.rar                                                                               2884ms  Wed Jul 29 02:54:15 2020
password= hello
Block header: crc 6152 type 72 (marker) flags 0x1a21 size 7  addsize 0
Block header: crc 90cf type 73 (archive) flags 0x0 size 13  addsize 0
  headersEncrypted False
Block header: crc 44dc type 74 (file) flags 0x9424 size 54  addsize 0
  has password
  has ext_time
  file salt b'728be58c227f8db4'
  file crc OK ?  True
Block header: crc 3dc4 type 7b (terminator) flags 0x4000 size 7  addsize 0

> python3 unarcrypto.py -p hello -v 1 tests/hello_pw_store_headers.rar                                                                        344ms  Wed Jul 29 02:55:03 2020
password= hello
Block header: crc 6152 type 72 (marker) flags 0x1a21 size 7  addsize 0
Block header: crc 99ce type 73 (archive) flags 0x80 size 13  addsize 0
  headersEncrypted True
header salt b'379475b06e303955'
iv b'e3dfe7498ad0faf3325f9ee9283a396c' key b'a002f7af8fc3b153436abb226f298747'
encrypted headers: AES key is OK
Block header: crc 4cd type 74 (file) flags 0x9424 size 54  addsize 0
  has password
  has ext_time
  file salt b'379475b06e303955'
  file crc OK ?  True
header salt b'379475b06e303955'
iv b'e3dfe7498ad0faf3325f9ee9283a396c' key b'a002f7af8fc3b153436abb226f298747'
encrypted headers: AES key is OK
Block header: crc 3dc4 type 7b (terminator) flags 0x4000 size 7  addsize 0

> python3 unarcrypto.py -p hello -v 1 tests/hello_pw_store_headers2.rar                                                                       724ms  Wed Jul 29 02:55:40 2020
password= hello
Block header: crc 6152 type 72 (marker) flags 0x1a21 size 7  addsize 0
Block header: crc 99ce type 73 (archive) flags 0x80 size 13  addsize 0
  headersEncrypted True
header salt b'86d6dabf466195dc'
iv b'223bcf9b6ad1c376047622108bfdf05c' key b'4c17206f78c6ccd81de9d8998895740d'
encrypted headers: AES key is OK
Block header: crc 6f5 type 74 (file) flags 0x9424 size 54  addsize 0
  has password
  has ext_time
  file salt b'86d6dabf466195dc'
  file crc OK ?  True
header salt b'86d6dabf466195dc'
iv b'223bcf9b6ad1c376047622108bfdf05c' key b'4c17206f78c6ccd81de9d8998895740d'
encrypted headers: AES key is OK
Block header: crc 3dc4 type 7b (terminator) flags 0x4000 size 7  addsize 0

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gotson avatar gotson commented on May 23, 2024

🎉 This issue has been resolved in version 7.3.0 🎉

The release is available on:

Your semantic-release bot 📦🚀

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