+"""
+Implements operations with CMS EnvelopedData and SignedData messages
+
+Contains function CMS() which parses CMS message and creates either
+EnvelopedData or SignedData objects (EncryptedData and CompressedData
+can be easily added, because OpenSSL contain nessesary function)
+
+Each of these objects contains create() static method which is used to
+create it from raw data and neccessary certificates.
+
+
+"""
+
+from ctypescrypto.exception import LibCryptoError
+from ctypescrypto.bio import Membio
+from ctypescrypto.oid import Oid
+
+class CMSError(LibCryptoError):
+ """
+ Exception which is raised when error occurs
+ """
+ pass
+
+class Flags:
+ """
+ Constants for flags passed to the CMS methods.
+ Can be OR-ed together
+ """
+ TEXT=1
+ NOCERTS=2
+ NO_CONTENT_VERIFY=4
+ NO_ATTR_VERIFY=8
+ NO_SIGS=NO_CONTENT_VERIFY|NO_ATTR_VERIFY
+ NOINTERN=0x10
+ NO_SIGNER_CERT_VERIFY=0x20
+ NO_VERIFY=0x20
+ DETACHED=0x40
+ BINARY=0x80
+ NOATTR=0x100
+ NOSMIMECAP =0x200
+ NOOLDMIMETYPE=0x400
+ CRLFEOL=0x800
+ STREAM=0x1000
+ NOCRL=0x2000
+ PARTIAL=0x4000
+ REUSE_DIGEST=0x8000
+ USE_KEYID=0x10000
+ DEBUG_DECRYPT=0x20000
+
+def CMS(data,format="PEM"):
+ """
+ Parses CMS data and returns either SignedData or EnvelopedData
+ object
+ """
+ b=Membio(data)
+ if format == "PEM":
+ ptr=libcrypto.PEM_read_bio_CMS(b.bio,None,None,None)
+ else:
+ ptr=libcrypto.d2i_CMS_bio(b.bio,None)
+ typeoid = Oid(libcrypto.OBJ_obj2nid(libcrypto.CMS_get0_type(ptr)))
+ if typeoid.shortname()=="pkcs7-signedData":
+ return SignedData(ptr)
+ elif typeoid.shortname()=="pkcs7-envelopedData":
+ return EnvelopedData(ptr)
+ else:
+ raise NotImplementedError("cannot handle "+typeoid.shortname())
+
+
+
+
+class SignedData:
+ def __init__(self,ptr=None):
+ self.ptr=ptr
+ @staticmethod
+ def create(data,cert,pkey,flags=Flags.BINARY):
+ """
+ Creates SignedData message by signing data with pkey and
+ certificate.
+
+ @param data - data to sign
+ @param pkey - pkey object with private key to sign
+ """
+ if not pkey.cansign:
+ raise ValueError("Specified keypair has no private part")
+ if cert.pubkey!=pkey:
+ raise ValueError("Certificate doesn't match public key")
+ b=Membio(data)
+ ptr=libcrypto.CMS_sign(cert.cert,pkey.ptr,None,b.bio,flags)
+ if ptr is None:
+ raise CMSError("signing message")
+ return SignedData(ptr)
+ def sign(self,cert,pkey,md=None,data=None,flags=Flags.BINARY):
+ """
+ Adds another signer to already signed message
+ @param cert - signer's certificate
+ @param pkey - signer's private key
+ @param data - data to sign (if detached)
+ @param md - message digest to use as DigestType object (if None - default for key
+ would be used)
+ @param flags - flags
+ """
+ if not pkey.cansign:
+ raise ValueError("Specified keypair has no private part")
+ if cert.pubkey!=pkey:
+ raise ValueError("Certificate doesn't match public key")
+ p1=libcrypto.CMS_sign_add1_Signer(self.ptr,cert.cert,pkey.ptr,
+ md.digest,flags)
+ if p1 is None:
+ raise CMSError("adding signer")
+ if flags & Flags.REUSE_DIGEST==0:
+ if data is not None:
+ b=Membio(data)
+ biodata=b.bio
+ else:
+ biodata=None
+ res= libcrypto.CMS_final(self.ptr,biodata,None,flags)
+ if res<=0:
+ raise CMSError
+ def verify(self,store,flags,data=None):
+ bio=None
+ if data!=None:
+ b=Membio(data)
+ bio=b.bio
+ res=libcrypto.CMS_verify(self.ptr,store.store,bio,None,flags)
+ return res>0
+ def __str__(self):
+ """
+ Serialize in DER format
+ """
+ b=Membio()
+ if not libcrypto.i2d_CMS_bio(b.bio,self.ptr):
+ raise CMSError("writing CMS to PEM")
+ return str(b)
+
+ def pem(self):
+ """
+ Serialize in PEM format
+ """
+ b=Membio()
+ if not libcrypto.PEM_write_bio_CMS(b.bio,self.ptr):
+ raise CMSError("writing CMS to PEM")
+ return str(b)
+
+ @property
+ def signers(self,store=None):
+ """
+ Return list of signer's certificates
+ """
+ raise NotImplementedError
+ @property
+ def data(self):
+ """
+ Returns signed data if present
+ """
+ raise NotImplementedError
+ def addcert(self,cert):
+ """
+ Adds a certificate (probably intermediate CA) to the SignedData
+ structure
+ """
+ raise NotImplementedError
+ def addcrl(self,crl):
+ """
+ Adds a CRL to the signed data structure
+ """
+ raise NotImplementedError
+ @property
+ def certs(self):
+ """
+ List of the certificates contained in the structure
+ """
+ raise NotImplementedError
+ @property
+ def crls(self):
+ """
+ List of the CRLs contained in the structure
+ """
+ raise NotImplementedError
+
+class EnvelopedData:
+ def __init__(self,ptr):
+ """
+ Initializes an object. For internal use
+ """
+ self.ptr=ptr
+ def __str__(self):
+ """
+ Serialize in DER format
+ """
+ b=Membio()
+ if not libcrypto.i2d_CMS_bio(b.bio,self.ptr):
+ raise CMSError("writing CMS to PEM")
+ return str(b)
+
+ def pem(self):
+ """
+ Serialize in PEM format
+ """
+ b=Membio()
+ if not libcrypto.PEM_write_bio_CMS(b.bio,self.ptr):
+ raise CMSError("writing CMS to PEM")
+ return str(b)
+ @staticmethod
+ def create(recipients,data,cipher,flags=0):
+ """
+ Creates and encrypts message
+ @param recipients - list of X509 objects
+ @param data - contents of the message
+ @param cipher - CipherType object
+ @param flags - flag
+ """
+ # Need to be able to handle OPENSSL stacks
+ raise NotImplementedError
+ def decrypt(self,pkey,cert,flags=0):
+ """
+ Decrypts message
+ @param pkey - private key to decrypt
+ @param cert - certificate of this private key (to find
+ neccessary RecipientInfo
+ @param flags - flags
+ @returns - decrypted data
+ """
+ if not pkey.cansign:
+ raise ValueError("Specified keypair has no private part")
+ if pkey != cert.pubkey:
+ raise ValueError("Certificate doesn't match private key")
+ b=Membio()
+ res=libcrypto.CMS_decrypt(self.ptr,pkey.ptr,cert.ccert,None,b.bio,flags)
+ if res<=0:
+ raise CMSError("decrypting CMS")
+ return str(b)
projects / oss / ctypescrypto.git / commitdiff