On Tue, May 31, 2016 at 01:52:32PM +0200, Stephan Mueller wrote: > > + * NOTE: Technically you can use one buffer for holding the label_context and > + * the outbuf in the example above. Howerver, multiple rounds of the > + * KDF are to be expected with the input must always be the same. > + * The first round would replace the input in case of one buffer, and the > + * KDF would calculate a cryptographically strong result which, however, > + * is not portable to other KDF implementations! Thus, always use > + * different buffers for the label_context and the outbuf. A safe > + * in-place operation can only be done when only one round of the KDF > + * is executed (i.e. the size of the requested buffer is equal to the > + * digestsize of the used MAC).
Why don't you put the result in a temporary buffer and then copy it? These things are tiny, right? Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
