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| author | Paul Kehrer <paul.l.kehrer@gmail.com> | 2018-07-17 21:49:03 +0800 |
|---|---|---|
| committer | Alex Gaynor <alex.gaynor@gmail.com> | 2018-07-17 09:49:03 -0400 |
| commit | d4378e42937b56f473ddade2667f919ce32208cb (patch) | |
| tree | f2374c70935a8b64e3b13d2d89314675d71cdeee /src | |
| parent | c574e7554c7aa27c56f6478258a4e18f79457652 (diff) | |
| download | cryptography-d4378e42937b56f473ddade2667f919ce32208cb.tar.gz cryptography-d4378e42937b56f473ddade2667f919ce32208cb.tar.bz2 cryptography-d4378e42937b56f473ddade2667f919ce32208cb.zip | |
disallow implicit tag truncation with finalize_with_tag (#4342)
Diffstat (limited to 'src')
| -rw-r--r-- | src/cryptography/hazmat/backends/openssl/ciphers.py | 5 | ||||
| -rw-r--r-- | src/cryptography/hazmat/primitives/ciphers/modes.py | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/src/cryptography/hazmat/backends/openssl/ciphers.py b/src/cryptography/hazmat/backends/openssl/ciphers.py index 462ffea2..e0ee06ee 100644 --- a/src/cryptography/hazmat/backends/openssl/ciphers.py +++ b/src/cryptography/hazmat/backends/openssl/ciphers.py @@ -199,6 +199,11 @@ class _CipherContext(object): "finalize_with_tag requires OpenSSL >= 1.0.2. To use this " "method please update OpenSSL" ) + if len(tag) < self._mode._min_tag_length: + raise ValueError( + "Authentication tag must be {0} bytes or longer.".format( + self._mode._min_tag_length) + ) res = self._backend._lib.EVP_CIPHER_CTX_ctrl( self._ctx, self._backend._lib.EVP_CTRL_AEAD_SET_TAG, len(tag), tag diff --git a/src/cryptography/hazmat/primitives/ciphers/modes.py b/src/cryptography/hazmat/primitives/ciphers/modes.py index 598dfaa4..543015fe 100644 --- a/src/cryptography/hazmat/primitives/ciphers/modes.py +++ b/src/cryptography/hazmat/primitives/ciphers/modes.py @@ -220,6 +220,7 @@ class GCM(object): min_tag_length) ) self._tag = tag + self._min_tag_length = min_tag_length tag = utils.read_only_property("_tag") initialization_vector = utils.read_only_property("_initialization_vector") |