Vitaly Chikunov
3da2c1dfdb
ecc_point_mult is supposed to be used with a regularized scalar, otherwise, it's possible to deduce the position of the top bit of the scalar with timing attack. This is important when the scalar is a private key. ecc_point_mult is already using a regular algorithm (i.e. having an operation flow independent of the input scalar) but regularization step is not implemented. Arrange scalar to always have fixed top bit by adding a multiple of the curve order (n). References: The constant time regularization step is based on micro-ecc by Kenneth MacKay and also referenced in the literature (Bernstein, D. J., & Lange, T. (2017). Montgomery curves and the Montgomery ladder. (Cryptology ePrint Archive; Vol. 2017/293). s.l.: IACR. Chapter 4.6.2.) Signed-off-by: Vitaly Chikunov <vt@altlinux.org> Cc: kernel-hardening@lists.openwall.com Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.