+ *) Fixed a padding oracle in PKCS7_dataDecode and CMS_decrypt_set1_pkey.
+ An attack is simple, if the first CMS_recipientInfo is valid but the
+ second CMS_recipientInfo is chosen ciphertext. If the second
+ recipientInfo decodes to PKCS #1 v1.5 form plaintext, the correct
+ encryption key will be replaced by garbage, and the message cannot be
+ decoded, but if the RSA decryption fails, the correct encryption key is
+ used and the recipient will not notice the attack.
+ As a work around for this potential attack the length of the decrypted
+ key must be equal to the cipher default key length, in case the
+ certifiate is not given and all recipientInfo are tried out.
+ The old behaviour can be re-enabled in the CMS code by setting the
+ CMS_DEBUG_DECRYPT flag.
+ [Bernd Edlinger]
+