• Stephan Mueller's avatar
    crypto: algif_aead - copy AAD from src to dst · 72548b09
    Stephan Mueller authored
    Use the NULL cipher to copy the AAD and PT/CT from the TX SGL
    to the RX SGL. This allows an in-place crypto operation on the
    RX SGL for encryption, because the TX data is always smaller or
    equal to the RX data (the RX data will hold the tag).
    
    For decryption, a per-request TX SGL is created which will only hold
    the tag value. As the RX SGL will have no space for the tag value and
    an in-place operation will not write the tag buffer, the TX SGL with the
    tag value is chained to the RX SGL. This now allows an in-place
    crypto operation.
    
    For example:
    
    * without the patch:
    kcapi -x 2 -e -c "gcm(aes)" -p 89154d0d4129d322e4487bafaa4f6b46 -k c0ece3e63198af382b5603331cc23fa8 -i 7e489b83622e7228314d878d -a afcd7202d621e06ca53b70c2bdff7fb2 -l 16 -u -s
    00000000000000000000000000000000f4a3eacfbdadd3b1a17117b1d67ffc1f1e21efbbc6d83724a8c296e3bb8cda0c
    
    * with the patch:
    kcapi -x 2 -e -c "gcm(aes)" -p 89154d0d4129d322e4487bafaa4f6b46 -k c0ece3e63198af382b5603331cc23fa8 -i 7e489b83622e7228314d878d -a afcd7202d621e06ca53b70c2bdff7fb2 -l 16 -u -s
    afcd7202d621e06ca53b70c2bdff7fb2f4a3eacfbdadd3b1a17117b1d67ffc1f1e21efbbc6d83724a8c296e3bb8cda0c
    
    Tests covering this functionality have been added to libkcapi.
    Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    72548b09
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