On Thu, Nov 03, 2016 at 01:30:49PM -0700, Andy Lutomirski wrote: > > Also, Herbert, it seems like the considerable majority of the crypto > code is acting on kernel virtual memory addresses and does software > processing. Would it perhaps make sense to add a kvec-based or > iov_iter-based interface to the crypto code? I bet it would be quite > a bit faster and it would make crypto on stack buffers work directly. I'd like to hear Herbert's opinion on this too, but as I understand it, if a symmetric cipher API operating on virtual addresses was added, similar to the existing "shash" API it would only allow software processing. Whereas with the current API you can request a transform and use it the same way regardless of whether the crypto framework has chosen a software or hardware implementation, or a combination thereof. If this wasn't a concern then I expect using virtual addresses would indeed simplify things a lot, at least for users not already working with physical memory (struct page). Either way, in the near term it looks like 4.9 will be released with the new behavior that encryption/decryption is not supported on stack buffers. Separately from the scatterwalk_map_and_copy() issue, today I've found two places in the filesystem-level encryption code that do encryption on stack buffers and therefore hit the 'BUG_ON(!virt_addr_valid(buf));' in sg_set_buf(). I will be sending patches to fix these, but I suspect there may be more crypto API users elsewhere that have this same problem. Eric -- 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
