U :vh U @svdZddlZddlZddlZddlZddlZddlmZddlm Z ddl m Z ddl m Z mZmZmZddlmZmZdd lmZdd lmZmZmZmZdd lmZz4dd lmZmZdd l m!Z!m"Z"ddl#m$Z$dZ%Wn(e&k rZ'ze'Z%W5dZ'['XYnXe(e)Z*GdddZ+GdddZ,GdddeZ-GdddZ.ee/e0fe/dddZ1e2e2dddZ3dS)a Utilities to perform encryption following the PDF standards. The contents of this module are internal to fpdf2, and not part of the public API. They may change at any time without prior warning or any deprecation period, in non-backward-compatible ways. N)hexlify) BOM_UTF16_BEurandom)CallableIterableTypeUnion)AccessPermissionEncryptionMethod) FPDFException)Name PDFObject PDFStringbuild_obj_dict)create_dictionary_string)Ciphermodes)AES128AES256)PKCS7c@sReZdZdZdZeedddZeee dddZ ee ee fed d d Z d S) ARC4az This is a simplified version of the ARC4 (alleged RC4) algorithm, created based on the following sources: * Wikipedia article on RC4 * github.com/manojpandey/rc4 (MIT License) * http://people.csail.mit.edu/rivest/pubs/RS14.pdf Having this ARC4 implementation makes it possible to have basic encryption functions without additional dependencies )keyreturncCsft|}tt|j}d}t|jD]<}|||||||j}||||||<||<q$|S)Nr)lenlistrangeMOD)selfr key_lengthSjir%3/tmp/pip-unpacked-wheel-dvf6lv8i/fpdf/encryption.pyKSA4szARC4.KSA)r"rccshd}d}|d|j}||||j}||||||<||<||||||j}|VqdS)Nrr )r)r r"r$r#Kr%r%r&PRGA=sz ARC4.PRGA)rtextrcCs4|||}g}|D]}||t|Aq|SN)r)r'appendnext)r rr*Z keystreamrescr%r%r&encryptGs z ARC4.encryptN)__name__ __module__ __qualname____doc__rbytesrr'rintr)r bytearrayr0r%r%r%r&r&s    rcs8eZdZdZeeddfdd ZedddZZS) CryptFilterzMRepresents one crypt filter, listed under CF inside the encryption dictionaryN)modelengthrcs0ttd|_t||_t|d|_dS)Nr8)super__init__rtypeZc_f_mr6r:)r r9r: __class__r%r&r=Rs   zCryptFilter.__init__rcs"tfddtD}t|S)Ncsi|]}|t|qSr%)getattr).0rr r%r& Ysz)CryptFilter.serialize..)rdirpdf_dict)r Zobj_dictr%rDr& serializeXszCryptFilter.serialize) r1r2r3r4strr6r=rH __classcell__r%r%r?r&r8Osr8cs(eZdZdZdddfdd ZZS)EncryptionDictionaryz This class represents an encryption dictionary PDF 32000 reference - Table 20 The PDF trailer must reference this object (/Encrypt) StandardSecurityHandlerN)security_handlerrcsttd|_|j|_|j|_d|j d|_d|j d|_ |jdkrd|j d|_ d|j d|_d|j d|_|j|_t|j|_|jsd|_|jrtd|ji|_|jtjkrtd|_td|_ntd|_td|_dS) NZStandard<>falsez/StdCFZIdentityZStdCF)r<r=rfilterr!r:revisionroupperuoeZo_eueZu_epermsversionvint32access_permissionpencrypt_metadatacfrGrHZc_fencryption_methodr NO_ENCRYPTIONZstm_fZstr_f)r rMr?r%r&r=ds*        zEncryptionDictionary.__init__)r1r2r3r4r=rJr%r%r?r&rK]srKc@seZdZdZdZdeejdfe e e dfeee dddZ e ddd d Z ed d d Ze e eefee e efdddZe ee dddZeeedddZe d ddZeedddZeeedddZeedeedd d!Zeede ed"d#d$Ze ed%d&d'Ze d d(d)Ze d d*d+Zeefedeeeed,d-d.Z dd d/d0Z!dd d1d2Z"dd d3d4Z#ed d5d6Z$dS)7rLa This class is referenced in the main PDF class and is used to handle all encryption functions * Calculate password and hashes * Provide encrypt method to be called by stream and strings * Set the access permissions on the document s (N^NuAdNV..h>/ dSizNF)owner_password user_password permissionrbr`cCs*||_|dkrdnd|B|_||_|r*|nd|_||_d|_d|_trf|jtj tj fkrft dt|jtj krd|_ d|_ |dtd|jd|_n|jtj krd |_ d |_ |d d |_td |jd|_nL|jtjkr d|_ d|_ |dtd|jd|_nd|_ d|_ |d||_dS)Nlpzucryptography module not available - Try: 'pip install cryptography' or use RC4 encryption method - Import error was: z1.6ZAESV2)r9r:rPz2.0rZAESV3ZV2z1.5)fpdfr^rdrerbrar! import_errorr AES_128AES_256EnvironmentErrorr[rSZ_set_min_pdf_versionr8rcr`)r rmrdrerfrbr`r%r%r&r=sJ       z StandardSecurityHandler.__init__)file_idrcCsf||_|dd|_|jdkrD|d|_|||n||_ | |_| |_ dS)z,File_id is the first hash of the PDF file idr !rP N) rrinfo_idrSget_random_byteskgenerate_user_password_rev6generate_owner_password_rev6generate_perms_rev6generate_owner_passwordrUgenerate_encryption_keygenerate_user_passwordrW)r rrr%r%r&generate_passwordss     z*StandardSecurityHandler.generate_passwordsrAcCst|S)zReturn an encryption dictionary)rKrDr%r%r&get_encryption_objsz*StandardSecurityHandler.get_encryption_obj)r*obj_idrcCs2td|t|ttfr&|||S|||S)zOMethod invoked by PDFObject and PDFContentStream to encrypt strings and streamsz Encrypting %s)LOGGERdebug isinstancer7r5encrypt_streamencrypt_string)r r*rr%r%r&r0s    zStandardSecurityHandler.encrypt)stringrrc Cs|jtjkrt|ddStd|z2|ddt| |d| dWSt k rdt t| t|d|ddYSXdS)NF)r0zEncrypting string: %szlatin-1rNrOz utf-16-be)rbr rcrrHrrencoder5 encrypt_byteshexrVUnicodeEncodeErrorrr7rdecode)r rrr%r%r&rs   (z&StandardSecurityHandler.encrypt_string)streamrrcCs |jtjkr|St|||Sr+)rbr rcr5r)r rrr%r%r&rs z&StandardSecurityHandler.encrypt_streamcCs|jtjtjfkSr+)rbr rorprDr%r%r&is_aes_algorithmsz(StandardSecurityHandler.is_aes_algorithm)datarcCstjddd}||j||d@jdddd|djd ddd|rh|td d d d g|}|r|||St ||S)a PDF32000 reference - Algorithm 1: Encryption of data using the RC4 or AES algorithms Append object ID and generation ID to the key and encrypt the data Generation ID is fixed as 0. Will need to revisit if the application start changing generation ID md5FZusedforsecurityirllittle byteordersignedrrksAlT) hashlibnewupdaterwto_bytesrr5digestencrypt_AES_cryptographyrr0)r rrhrr%r%r&rs  z%StandardSecurityHandler.encrypt_bytes)rrrcCst|d}td}||}||7}|jtjkrPt t |t |nt t |jt |}|}|||}|||S)zDEncrypts an array of bytes using AES algorithms (AES 128 or AES 256)rh)r7rvrpadderrfinalizerbr rorrrCBCrrw encryptorextend)r rrZivrZ padded_datacipherrr%r%r&rs     z0StandardSecurityHandler.encrypt_AES_cryptography)clssizercCst|S)z https://docs.python.org/3/library/os.html#os.urandom os.urandom will use OS-specific sources to generate random bytes suitable for cryptographic use r)rrr%r%r&rvsz(StandardSecurityHandler.get_random_bytes)rrrcsttdddt|dkr"tSdfdd|D}tjd|}ttdd d }|D]}||r\td |d q\tt td dd}||t j r||t j rtd |dt |drt |dstd |dt|dkr|dd}| dS)al PDF2.0 - ISO 32000-2:2020 All passwords for revision 6 shall be based on Unicode. Preprocessing of a user-provided password consists first of normalizing its representation by applying the "SASLPrep" profile (Internet RFC 4013) of the "stringprep" algorithm (Internet RFC 3454) to the supplied password using the Normalize and BiDi options. Next, the password string shall be converted to UTF-8 encoding, and then truncated to the first 127 bytes if the string is longer than 127 bytes Python offers a stringprep module with the tables mapped in methods )charrcSs(|sdSt|rdSt|r$dS|S)Nrg ) stringprep in_table_b1 in_table_c12rr%r%r&char_map/s  z8StandardSecurityHandler.prepare_string..char_mapr rgc3s|]}|VqdSr+r%)rCr/rr%r& =sz9StandardSecurityHandler.prepare_string..NFKCcSsZt|pXt|pXt|pXt|pXt|pXt|pXt|pXt|pXt |Sr+) rrin_table_c21_c22 in_table_c3 in_table_c4 in_table_c5 in_table_c6 in_table_c7 in_table_c8 in_table_c9rr%r%r& is_prohibitedCs*   z=StandardSecurityHandler.prepare_string..is_prohibitedz The password z contains prohibited characters)rfunrcstfdd|DS)Nc3s|]}|VqdSr+r%)rCrrr%r&r\szPStandardSecurityHandler.prepare_string..has_character..)any)rrr%rr& has_character[sz=StandardSecurityHandler.prepare_string..has_characterz+ contains invalid bidirectional characters.rNzUTF-8)rIrr5join unicodedata ucd_3_2_0 normalizeboolr rr in_table_d1 in_table_d2r)rrZprepared_stringrrrr%rr&prepare_string!s6          z&StandardSecurityHandler.prepare_string)passwordrcCsFt|dkr|dd}t|d}||jddt||S)z PDF32000 reference - Algorithm 2: Computing an encryption key Step (a) - Add the default padding at the end of provided password to make it 32 bit long rtNlatin1)rr7rrDEFAULT_PADDING)r rr_r%r%r&padded_passwordss   z'StandardSecurityHandler.padded_passwordcCs||j}tdD] }t|}q|dt|jd}||j}tdD]2}g}|D]}|||AqZt t ||}qNt | S)z PDF32000 reference - Algorithm 3: Computing the encryption dictionary's O (owner password) value The security handler is only using revision 3 or 4, so the legacy r2 version is not implemented here 3Nr;) rrdrrmathceilr!rer,rr0r5r)r m_Zrc4keyresultr$new_keyrwr%r%r&r{~s     z/StandardSecurityHandler.generate_owner_passwordcstjddd}|tj|tjt|j }t dD]2}g}|D]}| ||AqVt t|qJfddt dDtS)z PDF32000 reference - Algorithm 5: Computing the encryption dictionary's U (user password) value The security handler is only using revision 3 or 4, so the legacy r2 version is not implemented here rFrrc3s |]}|j|AVqdSr+)r)rCxrr r%r&rszAStandardSecurityHandler.generate_user_password..r)rrrr7rr5fromhexrurrwrr,rr0rr)r rrr$rrwr%rr&r}s  z.StandardSecurityHandler.generate_user_password)rinput_passwordsaltuser_keyrc Cst|||}d}|d7}|||}tt|ddt|dd}|}||d| } t | ddd} | dkrt| }n&| dkrt | }nt | }|dkr| d|dkrqq|ddS) zz Algorithm 2B - section 7.6.4.3.4 of the ISO 32000-2:2020 Applied on Security handlers revision 6 rr Nrrt@rlr) rsha256rrrrrrrrsumsha384sha512) rrrrrwZ round_numberZk1rre remainderr%r%r& compute_hashs  $z$StandardSecurityHandler.compute_hashc Cs||j}|st}|d}|d}|j||d||}||_|j||d}tt|t d}| }| |j |}||_dS)z Generating the U (user password) and UE (user encryption) for security handlers of revision 6 Algorithm 8 - Section 7.6.4.4.7 of the ISO 32000-2:2020 r;)rrN)rrer7rvrrrWrrrrrrrwrrY) r reZuser_validation_saltZ user_key_saltrWrrrrYr%r%r&rxs"     z3StandardSecurityHandler.generate_user_password_rev6c Cs||j}|s td|j|d}|d}|j||t|jd||}||_ |j||t|jd}t t |t d}|}||j|}||_dS)z Generating the O (owner password) and OE (owner encryption) for security handlers of revision 6 Algorithm 9 - Section 7.6.4.4.8 of the ISO 32000-2:2020 zInvalid owner password r;)rrrrN)rrdr rvrr5rrWrrUrrrrrrrwrrX) r rdZowner_validation_saltZowner_key_saltrUrrrrXr%r%r&rys2      z4StandardSecurityHandler.generate_owner_password_rev6cCsvd|jB}|jrdnd}|jdddd|d|d }tt|jt}| }| || }| |_ d S) u 7.6.4.4.9 Algorithm 10: Computing the encryption dictionary’s Perms (permissions) value (Security handlers of revision 6) of the ISO 32000-2:2020 lTFr;rFrsadbriN)r^r`rrvrrrwrECBrrrrrZ)r Zperms64br`Z perms_inputrrrZr%r%r&rzs z+StandardSecurityHandler.generate_perms_rev6cCstjddd}|||j|t|j||jd@j dddd|t|j |j dkr|j dkr|tddddg| d t|jd }td D] }t|d t|jd }q|S) zU PDF32000 reference Algorithm 2: Computing an encryption key rFrrirrNr;2)rrrrrer5rrUr^rrur`r[rrrr!rr)r rrrr%r%r&r|s"  z/StandardSecurityHandler.generate_encryption_key)%r1r2r3r4rr allr RC4rIr rr=r~rKrr7r5r6r0rrrrr classmethodrrvrrr{r}rrxryrzr|r%r%r%r&rL}sZ  7   Q #!rL)rrcCs tjddd}|||S)NrFr)rrrr)rrr%r%r&r)s r)nrcCs|d@}|dAdS)z%convert long to signed 32 bit integerrlr%)rr%r%r&r]/sr])4r4rloggingrrrbinasciircodecsrosrtypingrrrr enumsr r errorsr ZsyntaxrrrrrrG&cryptography.hazmat.primitives.ciphersrrZ1cryptography.hazmat.primitives.ciphers.algorithmsrrZ&cryptography.hazmat.primitives.paddingrrn ImportErrorerror getLoggerr1rrr8rKrLr5r7rr6r]r%r%r%r&s<       ) /