On Mon, Dec 05, 2016 at 03:26:19PM +0100, Stephan Mueller wrote: > Hi Herbert, > > Changes v4: restore the old behavior -- if the caller does not provide sufficient > output buffer size, return an error. > > ---8<--- > > For encryption, the AEAD ciphers require AAD || PT as input and generate > AAD || CT || Tag as output and vice versa for decryption. Prior to this > patch, the AF_ALG interface for AEAD ciphers requires the buffer to be > present as input for encryption. Similarly, the output buffer for > decryption required the presence of the tag buffer too. This implies > that the kernel reads / writes data buffers from/to kernel space > even though this operation is not required. > > This patch changes the AF_ALG AEAD interface to be consistent with the > in-kernel AEAD cipher requirements. > > Due to this handling, he changes are transparent to user space with one > exception: the return code of recv indicates the mount of output buffer. > That output buffer has a different size compared to before the patch > which implies that the return code of recv will also be different. > For example, a decryption operation uses 16 bytes AAD, 16 bytes CT and > 16 bytes tag, the AF_ALG AEAD interface before showed a recv return > code of 48 (bytes) whereas after this patch, the return code is 32 > since the tag is not returned any more. > > Reported-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> > Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx> Hmm, I don't see the code that copies the AAD over. Did I miss it? Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
