]> www.wagner.pp.ru Git - oss/ctypescrypto.git/blobdiff - ctypescrypto/x509.py
Converted tabs to spaces to make pylint happy
[oss/ctypescrypto.git] / ctypescrypto / x509.py
index bd056d32f6227bcba4593e26fd79d06504ee5097..159956d72f457dc3640a95db75007092f8408bb0 100644 (file)
@@ -16,452 +16,540 @@ from ctypescrypto.exception import LibCryptoError
 from ctypescrypto import libcrypto
 from datetime import datetime
 try:
-       from pytz import utc
+    from pytz import utc
 except ImportError:
-       from datetime import timedelta
-       ZERO=timedelta(0)
-       class UTC(datetime.tzinfo):
-               """tzinfo object for UTC. 
-                       If no pytz is available, we would use it.
-               """
+    from datetime import timedelta,tzinfo
+    ZERO=timedelta(0)
+    class UTC(tzinfo):
+        """tzinfo object for UTC. 
+            If no pytz is available, we would use it.
+        """
 
-               def utcoffset(self, dt):
-                       return ZERO
+        def utcoffset(self, dt):
+            return ZERO
 
-               def tzname(self, dt):
-                       return "UTC"
+        def tzname(self, dt):
+            return "UTC"
 
-               def dst(self, dt):
-                       return ZERO
+        def dst(self, dt):
+            return ZERO
 
-       utc=UTC()
+    utc=UTC()
 
-__all__ = ['X509Error','X509Name','X509Store','StackOfX509']
+__all__ = ['X509','X509Error','X509Name','X509Store','StackOfX509']
 
 class _validity(Structure):
-       """ ctypes representation of X509_VAL structure 
-               needed to access certificate validity period, because openssl
-               doesn't provide fuctions for it - only macros
-       """
-       _fields_ =      [('notBefore',c_void_p),('notAfter',c_void_p)]
+    """ ctypes representation of X509_VAL structure 
+        needed to access certificate validity period, because openssl
+        doesn't provide fuctions for it - only macros
+    """
+    _fields_ =  [('notBefore',c_void_p),('notAfter',c_void_p)]
 
 class _cinf(Structure):
-       """ ctypes representtion of X509_CINF structure 
-           neede to access certificate data, which are accessable only
-               via macros
-       """
-       _fields_ = [('version',c_void_p),
-               ('serialNumber',c_void_p),
-               ('sign_alg',c_void_p),
-               ('issuer',c_void_p),
-               ('validity',POINTER(_validity)),
-               ('subject',c_void_p),
-               ('pubkey',c_void_p),
-               ]
+    """ ctypes representtion of X509_CINF structure 
+        neede to access certificate data, which are accessable only
+        via macros
+    """
+    _fields_ = [('version',c_void_p),
+        ('serialNumber',c_void_p),
+        ('sign_alg',c_void_p),
+        ('issuer',c_void_p),
+        ('validity',POINTER(_validity)),
+        ('subject',c_void_p),
+        ('pubkey',c_void_p),
+        ('issuerUID',c_void_p),
+        ('subjectUID',c_void_p),
+        ('extensions',c_void_p),
+        ]
 
 class _x509(Structure):
-       """
-       ctypes represntation of X509 structure needed
-       to access certificate data which are accesable only via
-       macros, not functions
-       """
-       _fields_ = [('cert_info',POINTER(_cinf)),
-                               ('sig_alg',c_void_p),
-                               ('signature',c_void_p),
-                               # There are a lot of parsed extension fields there
-                               ]
+    """
+    ctypes represntation of X509 structure needed
+    to access certificate data which are accesable only via
+    macros, not functions
+    """
+    _fields_ = [('cert_info',POINTER(_cinf)),
+                ('sig_alg',c_void_p),
+                ('signature',c_void_p),
+                # There are a lot of parsed extension fields there
+                ]
 _px509 = POINTER(_x509)
 
-# X509_extlist is not exported yet, because is not implemented 
 class X509Error(LibCryptoError):
-       """
-       Exception, generated when some openssl function fail
-       during X509 operation
-       """
-       pass
+    """
+    Exception, generated when some openssl function fail
+    during X509 operation
+    """
+    pass
 
 
-class X509Name:
-       """
-       Class which represents X.509 distinguished name - typically 
-       a certificate subject name or an issuer name.
+class X509Name(object):
+    """
+    Class which represents X.509 distinguished name - typically 
+    a certificate subject name or an issuer name.
 
-       Now used only to represent information, extracted from the
-       certificate. Potentially can be also used to build DN when creating
-       certificate signing request
-       """
-       # XN_FLAG_SEP_COMMA_PLUS & ASN1_STRFLG_UTF8_CONVERT
-       PRINT_FLAG=0x10010
-       ESC_MSB=4
-       def __init__(self,ptr=None,copy=False):
-               """
-               Creates a X509Name object
-               @param ptr - pointer to X509_NAME C structure (as returned by some  OpenSSL functions
-               @param copy - indicates that this structure have to be freed upon object destruction
-               """
-               if ptr is not None:
-                       self.ptr=ptr
-                       self.need_free=copy
-                       self.writable=False
-               else:
-                       self.ptr=libcrypto.X509_NAME_new()
-                       self.need_free=True
-                       self.writable=True
-       def __del__(self):
-               """
-               Frees if neccessary
-               """
-               if self.need_free:
-                       libcrypto.X509_NAME_free(self.ptr)
-       def __str__(self):
-               """
-               Produces an ascii representation of the name, escaping all symbols > 0x80
-               Probably it is not what you want, unless your native language is English
-               """
-               b=Membio()
-               libcrypto.X509_NAME_print_ex(b.bio,self.ptr,0,self.PRINT_FLAG | self.ESC_MSB)
-               return str(b)
-       def __unicode__(self):
-               """
-               Produces unicode representation of the name. 
-               """
-               b=Membio()
-               libcrypto.X509_NAME_print_ex(b.bio,self.ptr,0,self.PRINT_FLAG)
-               return unicode(b)
-       def __len__(self):
-               """
-               return number of components in the name
-               """
-               return libcrypto.X509_NAME_entry_count(self.ptr)
-       def __cmp__(self,other):
-               """
-               Compares X509 names
-               """
-               return libcrypto.X509_NAME_cmp(self.ptr,other.ptr)
-       def __eq__(self,other):
-               return libcrypto.X509_NAME_cmp(self.ptr,other.ptr)==0
+    Now used only to represent information, extracted from the
+    certificate. Potentially can be also used to build DN when creating
+    certificate signing request
+    """
+    # XN_FLAG_SEP_COMMA_PLUS & ASN1_STRFLG_UTF8_CONVERT
+    PRINT_FLAG=0x10010
+    ESC_MSB=4
+    def __init__(self,ptr=None,copy=False):
+        """
+        Creates a X509Name object
+        @param ptr - pointer to X509_NAME C structure (as returned by some  OpenSSL functions
+        @param copy - indicates that this structure have to be freed upon object destruction
+        """
+        if ptr is not None:
+            self.ptr=ptr
+            self.need_free=copy
+            self.writable=False
+        else:
+            self.ptr=libcrypto.X509_NAME_new()
+            self.need_free=True
+            self.writable=True
+    def __del__(self):
+        """
+        Frees if neccessary
+        """
+        if self.need_free:
+            libcrypto.X509_NAME_free(self.ptr)
+    def __str__(self):
+        """
+        Produces an ascii representation of the name, escaping all symbols > 0x80
+        Probably it is not what you want, unless your native language is English
+        """
+        b=Membio()
+        libcrypto.X509_NAME_print_ex(b.bio,self.ptr,0,self.PRINT_FLAG | self.ESC_MSB)
+        return str(b)
+    def __unicode__(self):
+        """
+        Produces unicode representation of the name. 
+        """
+        b=Membio()
+        libcrypto.X509_NAME_print_ex(b.bio,self.ptr,0,self.PRINT_FLAG)
+        return unicode(b)
+    def __len__(self):
+        """
+        return number of components in the name
+        """
+        return libcrypto.X509_NAME_entry_count(self.ptr)
+    def __cmp__(self,other):
+        """
+        Compares X509 names
+        """
+        return libcrypto.X509_NAME_cmp(self.ptr,other.ptr)
+    def __eq__(self,other):
+        return libcrypto.X509_NAME_cmp(self.ptr,other.ptr)==0
 
-       def __getitem__(self,key):
-               if isinstance(key,Oid):
-                       # Return first matching field
-                       idx=libcrypto.X509_NAME_get_index_by_NID(self.ptr,key.nid,-1)
-                       if idx<0:
-                               raise KeyError("Key not found "+repr(Oid))
-                       entry=libcrypto.X509_NAME_get_entry(self.ptr,idx)
-                       s=libcrypto.X509_NAME_ENTRY_get_data(entry)
-                       b=Membio()
-                       libcrypto.ASN1_STRING_print_ex(b.bio,s,self.PRINT_FLAG)
-                       return unicode(b)
-               elif isinstance(key,int):
-                       # Return OID, string tuple
-                       entry=libcrypto.X509_NAME_get_entry(self.ptr,key)
-                       if entry is None:
-                               raise IndexError("name entry index out of range")
-                       obj=libcrypto.X509_NAME_ENTRY_get_object(entry)
-                       nid=libcrypto.OBJ_obj2nid(obj)
-                       if nid==0:
-                               buf=create_string_buffer(80)
-                               len=libcrypto.OBJ_obj2txt(buf,80,obj,1)
-                               oid=Oid(buf[0:len])
-                       else:
-                               oid=Oid(nid)
-                       s=libcrypto.X509_NAME_ENTRY_get_data(entry)
-                       b=Membio()
-                       libcrypto.ASN1_STRING_print_ex(b.bio,s,self.PRINT_FLAG)
-                       return (oid,unicode(b))
+    def __getitem__(self,key):
+        if isinstance(key,Oid):
+            # Return first matching field
+            idx=libcrypto.X509_NAME_get_index_by_NID(self.ptr,key.nid,-1)
+            if idx<0:
+                raise KeyError("Key not found "+str(Oid))
+            entry=libcrypto.X509_NAME_get_entry(self.ptr,idx)
+            s=libcrypto.X509_NAME_ENTRY_get_data(entry)
+            b=Membio()
+            libcrypto.ASN1_STRING_print_ex(b.bio,s,self.PRINT_FLAG)
+            return unicode(b)
+        elif isinstance(key,(int,long)):
+            # Return OID, string tuple
+            entry=libcrypto.X509_NAME_get_entry(self.ptr,key)
+            if entry is None:
+                raise IndexError("name entry index out of range")
+            oid=Oid.fromobj(libcrypto.X509_NAME_ENTRY_get_object(entry))
+            s=libcrypto.X509_NAME_ENTRY_get_data(entry)
+            b=Membio()
+            libcrypto.ASN1_STRING_print_ex(b.bio,s,self.PRINT_FLAG)
+            return (oid,unicode(b))
+        else:
+            raise TypeError("X509 NAME can be indexed by Oids or integers only")
 
-       def __setitem__(self,key,val):
-               if not self.writable:
-                       raise ValueError("Attempt to modify constant X509 object")
-class X509_extlist:
-       def __init__(self,ptr):
-               self.ptr=ptr
-       def __del__(self):
-               libcrypto.X509_NAME_free(self.ptr)
-       def __str__(self):
-               raise NotImplementedError
-       def __len__(self):
-               return libcrypto.X509_NAME_entry_count(self.ptr)
+    def __setitem__(self,key,val):
+        if not self.writable:
+            raise ValueError("Attempt to modify constant X509 object")
+        else:
+            raise NotImplementedError
+    def __delitem__(self,key):
+        if not self.writable:
+            raise ValueError("Attempt to modify constant X509 object")
+        else:
+            raise NotImplementedError
+    def __hash__(self):
+        return libcrypto.X509_NAME_hash(self.ptr)
 
-       def __getattr__(self,key):
-               raise NotImplementedError
-       def __setattr__(self,key,val):
-               raise NotImplementedError
+class _x509_ext(Structure):
+    """ Represens C structure X509_EXTENSION """
+    _fields_=[("object",c_void_p),
+            ("critical",c_int),
+            ("value",c_void_p)]
 
-       
+class X509_EXT(object):
+    """ Python object which represents a certificate extension """
+    def __init__(self,ptr,copy=False):
+        """ Initializes from the pointer to X509_EXTENSION.
+            If copy is True, creates a copy, otherwise just
+            stores pointer.
+        """
+        if copy:
+            self.ptr=libcrypto.X509_EXTENSION_dup(ptr)
+        else:
+            self.ptr=cast(ptr,POINTER(_x509_ext))
+    def __del__(self):
+        libcrypto.X509_EXTENSION_free(self.ptr)
+    def __str__(self):
+        b=Membio()
+        libcrypto.X509V3_EXT_print(b.bio,self.ptr,0x20010,0)
+        return str(b)
+    def __unicode__(self):
+        b=Membio()
+        libcrypto.X509V3_EXT_print(b.bio,self.ptr,0x20010,0)
+        return unicode(b)
+    @property
+    def oid(self):
+        return Oid.fromobj(self.ptr[0].object)
+    @property
+    def critical(self): 
+        return self.ptr[0].critical >0
+class _X509extlist(object): 
+    """
+    Represents list of certificate extensions
+    """
+    def __init__(self,cert):
+        self.cert=cert
+    def __len__(self):
+        return libcrypto.X509_get_ext_count(self.cert.cert)
+    def __getitem__(self,item):
+        p=libcrypto.X509_get_ext(self.cert.cert,item)
+        if p is None:
+            raise IndexError
+        return X509_EXT(p,True)
+    def find(self,oid):
+        """
+        Return list of extensions with given Oid
+        """
+        if not isinstance(oid,Oid):
+            raise TypeError("Need crytypescrypto.oid.Oid as argument")
+        found=[]
+        l=-1
+        end=len(self)
+        while True:
+            l=libcrypto.X509_get_ext_by_NID(self.cert.cert,oid.nid,l)
+            if l>=end or l<0:
+                 break
+            found.append(self[l])
+        return found
+    def find_critical(self,crit=True):
+        """
+        Return list of critical extensions (or list of non-cricital, if
+        optional second argument is False
+        """
+        if crit:
+            flag=1
+        else:
+            flag=0
+        found=[]
+        end=len(self)
+        l=-1
+        while True:
+            l=libcrypto.X509_get_ext_by_critical(self.cert.cert,flag,l)
+            if l>=end or l<0:
+                 break
+            found.append(self[l])
+        return found            
 
+class X509(object):
+    """
+    Represents X.509 certificate. 
+    """
+    def __init__(self,data=None,ptr=None,format="PEM"):
+        """
+        Initializes certificate
+        @param data - serialized certificate in PEM or DER format.
+        @param ptr - pointer to X509, returned by some openssl function. 
+            mutually exclusive with data
+        @param format - specifies data format. "PEM" or "DER", default PEM
+        """
+        if ptr is not None:
+            if data is not None: 
+                raise TypeError("Cannot use data and ptr simultaneously")
+            self.cert = ptr
+        elif data is None:
+            raise TypeError("data argument is required")
+        else:
+            b=Membio(data)
+            if format == "PEM":
+                self.cert=libcrypto.PEM_read_bio_X509(b.bio,None,None,None)
+            else:
+                self.cert=libcrypto.d2i_X509_bio(b.bio,None)
+            if self.cert is None:
+                raise X509Error("error reading certificate")
+        self.extensions=_X509extlist(self)      
+    def __del__(self):
+        """
+        Frees certificate object
+        """
+        libcrypto.X509_free(self.cert)
+    def __str__(self):
+        """ Returns der string of the certificate """
+        b=Membio()
+        if libcrypto.i2d_X509_bio(b.bio,self.cert)==0:
+            raise X509Error("error serializing certificate")
+        return str(b)
+    def __repr__(self):
+        """ Returns valid call to the constructor """
+        return "X509(data="+repr(str(self))+",format='DER')"
+    @property
+    def pubkey(self):
+        """EVP PKEy object of certificate public key"""
+        return PKey(ptr=libcrypto.X509_get_pubkey(self.cert,False))
+    def pem(self):
+        """ Returns PEM represntation of the certificate """
+        b=Membio()
+        if libcrypto.PEM_write_bio_X509(b.bio,self.cert)==0:
+            raise X509Error("error serializing certificate")
+        return str(b)
+    def verify(self,store=None,chain=[],key=None):  
+        """ 
+        Verify self. Supports verification on both X509 store object 
+        or just public issuer key
+        @param store X509Store object.
+        @param chain - list of X509 objects to add into verification
+            context.These objects are untrusted, but can be used to
+            build certificate chain up to trusted object in the store
+        @param key - PKey object with open key to validate signature
+        
+        parameters store and key are mutually exclusive. If neither 
+        is specified, attempts to verify self as self-signed certificate
+        """
+        if store is not None and key is not None:
+            raise X509Error("key and store cannot be specified simultaneously")
+        if store is not None:
+            ctx=libcrypto.X509_STORE_CTX_new()
+            if ctx is None:
+                raise X509Error("Error allocating X509_STORE_CTX")
+            if chain is not None and len(chain)>0:
+                ch=StackOfX509(chain)
+            else:
+                ch=None
+            if libcrypto.X509_STORE_CTX_init(ctx,store.store,self.cert,ch) < 0:
+                raise X509Error("Error allocating X509_STORE_CTX")
+            res= libcrypto.X509_verify_cert(ctx)
+            libcrypto.X509_STORE_CTX_free(ctx)
+            return res>0
+        else:
+            if key is None:
+                if self.issuer != self.subject:
+                    # Not a self-signed certificate
+                    return False
+                key = self.pubkey
+            res = libcrypto.X509_verify(self.cert,key.key)
+            if res < 0:
+                raise X509Error("X509_verify failed")
+            return res>0
+            
+    @property
+    def subject(self):
+        """ X509Name for certificate subject name """
+        return X509Name(libcrypto.X509_get_subject_name(self.cert))
+    @property
+    def issuer(self):
+        """ X509Name for certificate issuer name """
+        return X509Name(libcrypto.X509_get_issuer_name(self.cert))
+    @property
+    def serial(self):
+        """ Serial number of certificate as integer """
+        asnint=libcrypto.X509_get_serialNumber(self.cert)
+        b=Membio()
+        libcrypto.i2a_ASN1_INTEGER(b.bio,asnint)
+        return int(str(b),16)
+    @property 
+    def version(self):
+        """ certificate version as integer. Really certificate stores 0 for
+        version 1 and 2 for version 3, but we return 1 and 3 """
+        asn1int=cast(self.cert,_px509)[0].cert_info[0].version
+        return libcrypto.ASN1_INTEGER_get(asn1int)+1
+    @property
+    def startDate(self):
+        """ Certificate validity period start date """
+        # Need deep poke into certificate structure (x)->cert_info->validity->notBefore 
+        global utc
+        asn1date=cast(self.cert,_px509)[0].cert_info[0].validity[0].notBefore
+        b=Membio()
+        libcrypto.ASN1_TIME_print(b.bio,asn1date)
+        return datetime.strptime(str(b),"%b %d %H:%M:%S %Y %Z").replace(tzinfo=utc)
+    @property
+    def endDate(self):
+        """ Certificate validity period end date """
+        # Need deep poke into certificate structure (x)->cert_info->validity->notAfter
+        global utc
+        asn1date=cast(self.cert,_px509)[0].cert_info[0].validity[0].notAfter
+        b=Membio()
+        libcrypto.ASN1_TIME_print(b.bio,asn1date)
+        return datetime.strptime(str(b),"%b %d %H:%M:%S %Y %Z").replace(tzinfo=utc)
+    def check_ca(self):
+        """ Returns True if certificate is CA certificate """
+        return libcrypto.X509_check_ca(self.cert)>0
+class X509Store(object):
+    """
+        Represents trusted certificate store. Can be used to lookup CA 
+        certificates to verify
 
-class X509:
-       """
-       Represents X.509 certificate. 
-       """
-       def __init__(self,data=None,ptr=None,format="PEM"):
-               """
-               Initializes certificate
-               @param data - serialized certificate in PEM or DER format.
-               @param ptr - pointer to X509, returned by some openssl function. 
-                       mutually exclusive with data
-               @param format - specifies data format. "PEM" or "DER", default PEM
-               """
-               if ptr is not None:
-                       if data is not None: 
-                               raise TypeError("Cannot use data and ptr simultaneously")
-                       self.cert = ptr
-               elif data is None:
-                       raise TypeError("data argument is required")
-               else:
-                       b=Membio(data)
-                       if format == "PEM":
-                               self.cert=libcrypto.PEM_read_bio_X509(b.bio,None,None,None)
-                       else:
-                               self.cert=libcrypto.d2i_X509_bio(b.bio,None)
-                       if self.cert is None:
-                               raise X509Error("error reading certificate")
-       def __del__(self):
-               """
-               Frees certificate object
-               """
-               libcrypto.X509_free(self.cert)
-       def __str__(self):
-               """ Returns der string of the certificate """
-               b=Membio()
-               if libcrypto.i2d_X509_bio(b.bio,self.cert)==0:
-                       raise X509Error("error serializing certificate")
-               return str(b)
-       def __repr__(self):
-               """ Returns valid call to the constructor """
-               return "X509(data="+repr(str(self))+",format='DER')"
-       @property
-       def pubkey(self):
-               """EVP PKEy object of certificate public key"""
-               return PKey(ptr=libcrypto.X509_get_pubkey(self.cert,False))
-       def verify(self,store=None,chain=[],key=None):  
-               """ 
-               Verify self. Supports verification on both X509 store object 
-               or just public issuer key
-               @param store X509Store object.
-               @param chain - list of X509 objects to add into verification
-                       context.These objects are untrusted, but can be used to
-                       build certificate chain up to trusted object in the store
-               @param key - PKey object with open key to validate signature
-               
-               parameters store and key are mutually exclusive. If neither 
-               is specified, attempts to verify self as self-signed certificate
-               """
-               if store is not None and key is not None:
-                       raise X509Error("key and store cannot be specified simultaneously")
-               if store is not None:
-                       ctx=libcrypto.X509_STORE_CTX_new()
-                       if ctx is None:
-                               raise X509Error("Error allocating X509_STORE_CTX")
-                       if chain is not None and len(chain)>0:
-                               ch=StackOfX509(chain)
-                       else:
-                               ch=None
-                       if libcrypto.X509_STORE_CTX_init(ctx,store.store,self.cert,ch) < 0:
-                               raise X509Error("Error allocating X509_STORE_CTX")
-                       res= libcrypto.X509_verify_cert(ctx)
-                       libcrypto.X509_STORE_CTX_free(ctx)
-                       return res>0
-               else:
-                       if key is None:
-                               if self.issuer != self.subject:
-                                       # Not a self-signed certificate
-                                       return False
-                               key = self.pubkey
-                       res = libcrypto.X509_verify(self.cert,key.key)
-                       if res < 0:
-                               raise X509Error("X509_verify failed")
-                       return res>0
-                       
-       @property
-       def subject(self):
-               """ X509Name for certificate subject name """
-               return X509Name(libcrypto.X509_get_subject_name(self.cert))
-       @property
-       def issuer(self):
-               """ X509Name for certificate issuer name """
-               return X509Name(libcrypto.X509_get_issuer_name(self.cert))
-       @property
-       def serial(self):
-               """ Serial number of certificate as integer """
-               asnint=libcrypto.X509_get_serialNumber(self.cert)
-               b=Membio()
-               libcrypto.i2a_ASN1_INTEGER(b.bio,asnint)
-               return int(str(b),16)
-       @property 
-       def version(self):
-               """ certificate version as integer. Really certificate stores 0 for
-               version 1 and 2 for version 3, but we return 1 and 3 """
-               asn1int=cast(self.cert,_px509)[0].cert_info[0].version
-               return libcrypto.ASN1_INTEGER_get(asn1int)+1
-       @property
-       def startDate(self):
-               """ Certificate validity period start date """
-               # Need deep poke into certificate structure (x)->cert_info->validity->notBefore 
-               global utc
-               asn1date=cast(self.cert,_px509)[0].cert_info[0].validity[0].notBefore
-               b=Membio()
-               libcrypto.ASN1_TIME_print(b.bio,asn1date)
-               return datetime.strptime(str(b),"%b %d %H:%M:%S %Y %Z").replace(tzinfo=utc)
-       @property
-       def endDate(self):
-               """ Certificate validity period end date """
-               # Need deep poke into certificate structure (x)->cert_info->validity->notAfter
-               global utc
-               asn1date=cast(self.cert,_px509)[0].cert_info[0].validity[0].notAfter
-               b=Membio()
-               libcrypto.ASN1_TIME_print(b.bio,asn1date)
-               return datetime.strptime(str(b),"%b %d %H:%M:%S %Y %Z").replace(tzinfo=utc)
-       def extensions(self):
-               """ Returns list of extensions """
-               raise NotImplementedError
-       def check_ca(self):
-               """ Returns True if certificate is CA certificate """
-               return libcrypto.X509_check_ca(self.cert)>0
-class X509Store:
-       """
-               Represents trusted certificate store. Can be used to lookup CA 
-               certificates to verify
+        @param file - file with several certificates and crls 
+                to load into store
+        @param dir - hashed directory with certificates and crls
+        @param default - if true, default verify location (directory) 
+            is installed
 
-               @param file - file with several certificates and crls 
-                               to load into store
-               @param dir - hashed directory with certificates and crls
-               @param default - if true, default verify location (directory) 
-                       is installed
-
-       """
-       def __init__(self,file=None,dir=None,default=False):
-               """
-               Creates X509 store and installs lookup method. Optionally initializes 
-               by certificates from given file or directory.
-               """
-               #
-               # Todo - set verification flags
-               # 
-               self.store=libcrypto.X509_STORE_new()
-               if self.store is None:
-                       raise X509Error("allocating store")
-               lookup=libcrypto.X509_STORE_add_lookup(self.store,libcrypto.X509_LOOKUP_file())
-               if lookup is None:
-                       raise X509Error("error installing file lookup method")
-               if (file is not None):
-                       if not libcrypto.X509_LOOKUP_ctrl(lookup,1,file,1,None)>0:
-                               raise X509Error("error loading trusted certs from file "+file)
-               lookup=libcrypto.X509_STORE_add_lookup(self.store,libcrypto.X509_LOOKUP_hash_dir())
-               if lookup is None:
-                       raise X509Error("error installing hashed lookup method")
-               if dir is not None:
-                       if not libcrypto.X509_LOOKUP_ctrl(lookup,2,dir,1,None)>0:
-                               raise X509Error("error adding hashed  trusted certs dir "+dir)
-               if default:
-                       if not libcrypto.X509_LOOKUP_ctrl(lookup,2,None,3,None)>0:
-                               raise X509Error("error adding default trusted certs dir ")
-       def add_cert(self,cert):
-               """
-               Explicitely adds certificate to set of trusted in the store
-               @param cert - X509 object to add
-               """
-               if not isinstance(cert,X509):
-                       raise TypeError("cert should be X509")
-               libcrypto.X509_STORE_add_cert(self.store,cert.cert)
-       def add_callback(self,callback):
-               """
-               Installs callbac function, which would receive detailed information
-               about verified ceritificates
-               """
-               raise NotImplementedError
-       def setflags(self,flags):
-               """
-               Set certificate verification flags.
-               @param flags - integer bit mask. See OpenSSL X509_V_FLAG_* constants
-               """
-               libcrypto.X509_STORE_set_flags(self.store,flags)        
-       def setpurpose(self,purpose):
-               """
-               Sets certificate purpose which verified certificate should match
-               @param purpose - number from 1 to 9 or standard strind defined in Openssl
-               possible strings - sslcient,sslserver, nssslserver, smimesign,smimeencrypt, crlsign, any,ocsphelper
-               """
-               if isinstance(purpose,str):
-                       purp_no=X509_PURPOSE_get_by_sname(purpose)
-                       if purp_no <=0:
-                               raise X509Error("Invalid certificate purpose '"+purpose+"'")
-               elif isinstance(purpose,int):
-                       purp_no = purpose
-               if libcrypto.X509_STORE_set_purpose(self.store,purp_no)<=0:
-                       raise X509Error("cannot set purpose")
-       def setdepth(self,depth):
-               libcrypto.X509_STORE_set_depth(self.store,depth)
-       def settime(self, time):
-               """
-               Set point in time used to check validity of certificates for
-               """
-               if isinstance(time,datetime.datetime) or isinstance(time,datetime.date):
-                       d=int(time.strftime("%s"))
-               elif isinstance(time,int):
-                       pass
-               else:
-                       raise TypeError("datetime.date, datetime.datetime or integer is required as time argument")
-               raise NotImplementedError
-class StackOfX509:
-       """
-       Implements OpenSSL STACK_OF(X509) object.
-       It looks much like python container types
-       """
-       def __init__(self,certs=None,ptr=None,disposable=True):
-               """
-               Create stack
-               @param certs - list of X509 objects. If specified, read-write
-                       stack is created and populated by these certificates
-               @param ptr - pointer to OpenSSL STACK_OF(X509) as returned by
-                       some functions
-               @param disposable - if True, stack created from object, returned
-                               by function is copy, and can be modified and need to be
-                               freeid. If false, it is just pointer into another
-                               structure i.e. CMS_ContentInfo
-               """
-               if  ptr is None:
-                       self.need_free = True
-                       self.ptr=libcrypt.sk_new_null()
-                       if certs is not None:
-                               for crt in certs:
-                                       self.append(crt)
-               elif not certs is None:
-                               raise ValueError("cannot handle certs an ptr simultaneously")
-               else:
-                       self.need_free = disposable
-                       self.ptr=ptr
-       def __len__(self):
-               return libcrypto.sk_num(self.ptr)
-       def __getitem__(self,index):
-               if index <0 or index>=len(self):
-                       raise IndexError
-               p=libcrypto.sk_value(self.ptr,index)
-               return X509(ptr=libcrypto.X509_dup(p))
-       def __putitem__(self,index,value):
-               if not self.need_free:
-                       raise ValueError("Stack is read-only")
-               if index <0 or index>=len(self):
-                       raise IndexError
-               p=libcrypto.sk_set(self.ptr,index,libcrypto.X509_dup(value.cert))
-               libcrypto.X509_free(p)
-       def __delitem__(self,index):    
-               if not self.need_free:
-                       raise ValueError("Stack is read-only")
-               if index <0 or index>=len(self):
-                       raise IndexError
-               p=libcrypto.sk_delete(self.ptr,index)
-               libcrypto.X509_free(p)
-       def __del__(self):
-               if self.need_free:
-                       libcrypto.sk_pop_free(self.ptr,libcrypto.X509_free)
-       def append(self,value):
-               if not self.need_free:
-                       raise ValueError("Stack is read-only")
-               libcrypto.sk_push(self.ptr,libcrypto.X509_dup(value.cert))
+    """
+    def __init__(self,file=None,dir=None,default=False):
+        """
+        Creates X509 store and installs lookup method. Optionally initializes 
+        by certificates from given file or directory.
+        """
+        #
+        # Todo - set verification flags
+        # 
+        self.store=libcrypto.X509_STORE_new()
+        if self.store is None:
+            raise X509Error("allocating store")
+        lookup=libcrypto.X509_STORE_add_lookup(self.store,libcrypto.X509_LOOKUP_file())
+        if lookup is None:
+            raise X509Error("error installing file lookup method")
+        if (file is not None):
+            if not libcrypto.X509_LOOKUP_ctrl(lookup,1,file,1,None)>0:
+                raise X509Error("error loading trusted certs from file "+file)
+        lookup=libcrypto.X509_STORE_add_lookup(self.store,libcrypto.X509_LOOKUP_hash_dir())
+        if lookup is None:
+            raise X509Error("error installing hashed lookup method")
+        if dir is not None:
+            if not libcrypto.X509_LOOKUP_ctrl(lookup,2,dir,1,None)>0:
+                raise X509Error("error adding hashed  trusted certs dir "+dir)
+        if default:
+            if not libcrypto.X509_LOOKUP_ctrl(lookup,2,None,3,None)>0:
+                raise X509Error("error adding default trusted certs dir ")
+    def add_cert(self,cert):
+        """
+        Explicitely adds certificate to set of trusted in the store
+        @param cert - X509 object to add
+        """
+        if not isinstance(cert,X509):
+            raise TypeError("cert should be X509")
+        libcrypto.X509_STORE_add_cert(self.store,cert.cert)
+    def add_callback(self,callback):
+        """
+        Installs callback function, which would receive detailed information
+        about verified ceritificates
+        """
+        raise NotImplementedError
+    def setflags(self,flags):
+        """
+        Set certificate verification flags.
+        @param flags - integer bit mask. See OpenSSL X509_V_FLAG_* constants
+        """
+        libcrypto.X509_STORE_set_flags(self.store,flags)    
+    def setpurpose(self,purpose):
+        """
+        Sets certificate purpose which verified certificate should match
+        @param purpose - number from 1 to 9 or standard strind defined in Openssl
+        possible strings - sslcient,sslserver, nssslserver, smimesign,smimeencrypt, crlsign, any,ocsphelper
+        """
+        if isinstance(purpose,str):
+            purp_no=X509_PURPOSE_get_by_sname(purpose)
+            if purp_no <=0:
+                raise X509Error("Invalid certificate purpose '"+purpose+"'")
+        elif isinstance(purpose,int):
+            purp_no = purpose
+        if libcrypto.X509_STORE_set_purpose(self.store,purp_no)<=0:
+            raise X509Error("cannot set purpose")
+    def setdepth(self,depth):
+        """
+        Sets the verification depth i.e. max length of certificate chain
+        which is acceptable
+        """
+        libcrypto.X509_STORE_set_depth(self.store,depth)
+    def settime(self, time):
+        """
+        Set point in time used to check validity of certificates for
+        Time can be either python datetime object or number of seconds
+        sinse epoch
+        """
+        if isinstance(time,datetime.datetime) or isinstance(time,datetime.date):
+            d=int(time.strftime("%s"))
+        elif isinstance(time,int):
+            pass
+        else:
+            raise TypeError("datetime.date, datetime.datetime or integer is required as time argument")
+        raise NotImplementedError
+class StackOfX509(object):
+    """
+    Implements OpenSSL STACK_OF(X509) object.
+    It looks much like python container types
+    """
+    def __init__(self,certs=None,ptr=None,disposable=True):
+        """
+        Create stack
+        @param certs - list of X509 objects. If specified, read-write
+            stack is created and populated by these certificates
+        @param ptr - pointer to OpenSSL STACK_OF(X509) as returned by
+            some functions
+        @param disposable - if True, stack created from object, returned
+                by function is copy, and can be modified and need to be
+                freeid. If false, it is just pointer into another
+                structure i.e. CMS_ContentInfo
+        """
+        if  ptr is None:
+            self.need_free = True
+            self.ptr=libcrypto.sk_new_null()
+            if certs is not None:
+                for crt in certs:
+                    self.append(crt)
+        elif certs is not None:
+                raise ValueError("cannot handle certs an ptr simultaneously")
+        else:
+            self.need_free = disposable
+            self.ptr=ptr
+    def __len__(self):
+        return libcrypto.sk_num(self.ptr)
+    def __getitem__(self,index):
+        if index <0 or index>=len(self):
+            raise IndexError
+        p=libcrypto.sk_value(self.ptr,index)
+        return X509(ptr=libcrypto.X509_dup(p))
+    def __setitem__(self,index,value):
+        if not self.need_free:
+            raise ValueError("Stack is read-only")
+        if index <0 or index>=len(self):
+            raise IndexError
+        if not isinstance(value,X509):
+            raise TypeError('StackOfX508 can contain only X509 objects')
+        p=libcrypto.sk_value(self.ptr,index)
+        libcrypto.sk_set(self.ptr,index,libcrypto.X509_dup(value.cert))
+        libcrypto.X509_free(p)
+    def __delitem__(self,index):    
+        if not self.need_free:
+            raise ValueError("Stack is read-only")
+        if index <0 or index>=len(self):
+            raise IndexError
+        p=libcrypto.sk_delete(self.ptr,index)
+        libcrypto.X509_free(p)
+    def __del__(self):
+        if self.need_free:
+            libcrypto.sk_pop_free(self.ptr,libcrypto.X509_free)
+    def append(self,value):
+        if not self.need_free:
+            raise ValueError("Stack is read-only")
+        if not isinstance(value,X509):
+            raise TypeError('StackOfX508 can contain only X509 objects')
+        libcrypto.sk_push(self.ptr,libcrypto.X509_dup(value.cert))
 libcrypto.i2a_ASN1_INTEGER.argtypes=(c_void_p,c_void_p)
 libcrypto.ASN1_STRING_print_ex.argtypes=(c_void_p,c_void_p,c_long)
+libcrypto.PEM_read_bio_X509.restype=c_void_p
+libcrypto.PEM_read_bio_X509.argtypes=(c_void_p,POINTER(c_void_p),c_void_p,c_void_p)
+libcrypto.PEM_write_bio_X509.restype=c_int
+libcrypto.PEM_write_bio_X509.argtypes=(c_void_p,c_void_p)
 libcrypto.ASN1_TIME_print.argtypes=(c_void_p,c_void_p)
 libcrypto.ASN1_INTEGER_get.argtypes=(c_void_p,)
 libcrypto.ASN1_INTEGER_get.restype=c_long
@@ -479,4 +567,18 @@ libcrypto.X509_LOOKUP_file.restype=c_void_p
 libcrypto.X509_LOOKUP_hash_dir.restype=c_void_p
 libcrypto.X509_LOOKUP_ctrl.restype=c_int
 libcrypto.X509_LOOKUP_ctrl.argtypes=(c_void_p,c_int,c_char_p,c_long,POINTER(c_char_p))
-
+libcrypto.X509_EXTENSION_dup.argtypes=(c_void_p,)
+libcrypto.X509_EXTENSION_dup.restype=POINTER(_x509_ext)
+libcrypto.X509V3_EXT_print.argtypes=(c_void_p,POINTER(_x509_ext),c_long,c_int)
+libcrypto.X509_get_ext.restype=c_void_p
+libcrypto.X509_get_ext.argtypes=(c_void_p,c_int)
+libcrypto.X509V3_EXT_print.argtypes=(c_void_p,POINTER(_x509_ext),c_long,c_int)
+libcrypto.sk_set.argtypes=(c_void_p,c_int,c_void_p)
+libcrypto.sk_set.restype=c_void_p
+libcrypto.sk_value.argtypes=(c_void_p,c_int)
+libcrypto.sk_value.restype=c_void_p
+libcrypto.X509_dup.restype=c_void_p
+libcrypto.sk_new_null.restype=c_void_p
+libcrypto.X509_dup.argtypes=(c_void_p,)
+libcrypto.X509_NAME_hash.restype=c_long
+libcrypto.X509_NAME_hash.argtypes=(c_void_p,)