o
    c                     @   sd   d dl Z d dlmZmZmZ d dlmZ d dlmZ e j	r)d dlm
Z
 d dlmZ G dd dZdS )	    N)InvalidSignatureUnsupportedAlgorithm_Reasons)constant_time)CBC)ciphers)Backendc                   @   s`   e Zd Z	d					dddZd	eddfd
dZdefddZdddZdeddfddZdS )_CMACContextNbackendr   	algorithmciphers.BlockCipherAlgorithmreturnc           	      C   s   | |stdtj|| _|j| _|| _|jd | _	|d u ro| jj
}|t|tf }|| j|t}| jj }| j|| jjjk | jj|| jjj}| jj| j}| jj||t| j|| jjj}| j|dk || _d S )Nz#This backend does not support CMAC.      )Zcmac_algorithm_supportedr   r   ZUNSUPPORTED_CIPHER_backendkey_key
_algorithm
block_size_output_lengthZ_cipher_registrytyper   _libCMAC_CTX_newopenssl_assert_ffiNULLgcCMAC_CTX_freefrom_bufferZ	CMAC_Initlen_ctx)	selfr
   r   ctxregistryadapterZ
evp_cipherZkey_ptrres r&   Musr/lib/python3.10/site-packages/cryptography/hazmat/backends/openssl/cmac.py__init__   s4   

z_CMACContext.__init__datac                 C   s,   | j j| j|t|}| j |dk d S )Nr   )r   r   ZCMAC_Updater    r   r   )r!   r)   r%   r&   r&   r'   update=   s   z_CMACContext.updatec                 C   sd   | j jd| j}| j jd| j}| j j| j||}| j |dk d | _| j j|d d  S )Nzunsigned char[]zsize_t *r   )	r   r   newr   r   Z
CMAC_Finalr    r   buffer)r!   buflengthr%   r&   r&   r'   finalizeA   s   z_CMACContext.finalizec                 C   sV   | j j }| j j|| j jj}| j j|| j}| j |dk t	| j | j
|dS )Nr   )r"   )r   r   r   r   r   r   ZCMAC_CTX_copyr    r   r	   r   )r!   Z
copied_ctxr%   r&   r&   r'   copyK   s   
z_CMACContext.copy	signaturec                 C   s    |   }t||stdd S )NzSignature did not match digest.)r/   r   Zbytes_eqr   )r!   r1   digestr&   r&   r'   verifyT   s   z_CMACContext.verify)N)r
   r   r   r   r   N)r   r	   )	__name__
__module____qualname__r(   bytesr*   r/   r0   r3   r&   r&   r&   r'   r	      s    
(

	r	   )typingZcryptography.exceptionsr   r   r   Zcryptography.hazmat.primitivesr   Z,cryptography.hazmat.primitives.ciphers.modesr   TYPE_CHECKINGr   Z,cryptography.hazmat.backends.openssl.backendr   r	   r&   r&   r&   r'   <module>   s   