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crypto: keembay-ocs-aes - Fix 'q' assignment during CCM B0 generation
In ocs_aes_ccm_write_b0(), 'q' (the octet length of the binary representation of the octet length of the payload) is set to 'iv[0]', while it should be set to 'iv[0] & 0x7' (i.e., only the last 3 bits of iv[0] should be used), as documented in NIST Special Publication 800-38C: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38c.pdf In practice, this is not an issue, since 'iv[0]' is checked to be in the range [1-7] by ocs_aes_validate_inputs(), but let's fix the assignment anyway, in order to make the code more robust. Signed-off-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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committed by
Herbert Xu
parent
cfb28fde08
commit
0db5bc85c5
@@ -1080,15 +1080,15 @@ static int ocs_aes_ccm_write_b0(const struct ocs_aes_dev *aes_dev,
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/*
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/*
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* q is the octet length of Q.
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* q is the octet length of Q.
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* q can only be an element of {2, 3, 4, 5, 6, 7, 8} and is encoded as
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* q can only be an element of {2, 3, 4, 5, 6, 7, 8} and is encoded as
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* q - 1 == iv[0]
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* q - 1 == iv[0] & 0x7;
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*/
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*/
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b0[0] |= iv[0] & 0x7;
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b0[0] |= iv[0] & 0x7;
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/*
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/*
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* Copy the Nonce N from IV to B0; N is located in iv[1]..iv[15 - q]
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* Copy the Nonce N from IV to B0; N is located in iv[1]..iv[15 - q]
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* and must be copied to b0[1]..b0[15-q].
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* and must be copied to b0[1]..b0[15-q].
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* q == iv[0] + 1
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* q == (iv[0] & 0x7) + 1
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*/
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*/
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q = iv[0] + 1;
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q = (iv[0] & 0x7) + 1;
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for (i = 1; i <= 15 - q; i++)
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for (i = 1; i <= 15 - q; i++)
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b0[i] = iv[i];
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b0[i] = iv[i];
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/*
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/*
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