From beae2db127d3b5017cbcf685da9de7a9ef496541 Mon Sep 17 00:00:00 2001 From: sepro Date: Sun, 3 Nov 2024 21:03:09 +0100 Subject: [PATCH] [aes] Fix GCM pad length calculation (#11438) Closes #10169 Authored by: seproDev --- test/test_aes.py | 12 ++++++++++++ yt_dlp/aes.py | 4 ++-- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/test/test_aes.py b/test/test_aes.py index 5f975efec..6fe6059a1 100644 --- a/test/test_aes.py +++ b/test/test_aes.py @@ -83,6 +83,18 @@ class TestAES(unittest.TestCase): data, intlist_to_bytes(self.key), authentication_tag, intlist_to_bytes(self.iv[:12])) self.assertEqual(decrypted.rstrip(b'\x08'), self.secret_msg) + def test_gcm_aligned_decrypt(self): + data = b'\x159Y\xcf5eud\x90\x9c\x85&]\x14\x1d\x0f' + authentication_tag = b'\x08\xb1\x9d!&\x98\xd0\xeaRq\x90\xe6;\xb5]\xd8' + + decrypted = intlist_to_bytes(aes_gcm_decrypt_and_verify( + list(data), self.key, list(authentication_tag), self.iv[:12])) + self.assertEqual(decrypted.rstrip(b'\x08'), self.secret_msg[:16]) + if Cryptodome.AES: + decrypted = aes_gcm_decrypt_and_verify_bytes( + data, bytes(self.key), authentication_tag, bytes(self.iv[:12])) + self.assertEqual(decrypted.rstrip(b'\x08'), self.secret_msg[:16]) + def test_decrypt_text(self): password = intlist_to_bytes(self.key).decode() encrypted = base64.b64encode( diff --git a/yt_dlp/aes.py b/yt_dlp/aes.py index abf54a998..be67b40fe 100644 --- a/yt_dlp/aes.py +++ b/yt_dlp/aes.py @@ -230,11 +230,11 @@ def aes_gcm_decrypt_and_verify(data, key, tag, nonce): iv_ctr = inc(j0) decrypted_data = aes_ctr_decrypt(data, key, iv_ctr + [0] * (BLOCK_SIZE_BYTES - len(iv_ctr))) - pad_len = len(data) // 16 * 16 + pad_len = (BLOCK_SIZE_BYTES - (len(data) % BLOCK_SIZE_BYTES)) % BLOCK_SIZE_BYTES s_tag = ghash( hash_subkey, data - + [0] * (BLOCK_SIZE_BYTES - len(data) + pad_len) # pad + + [0] * pad_len # pad + bytes_to_intlist((0 * 8).to_bytes(8, 'big') # length of associated data + ((len(data) * 8).to_bytes(8, 'big'))), # length of data )