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deps: float 949ff366 from openssl (ECDSA blinding) (6.x backport)

Rodrigo Muino Tomonari requested to merge github/fork/rvagg/rvagg/openssl-949ff366-6.x into v6.x-staging

Same as https://github.com/nodejs/node/pull/21345 but for 1.0.2 on 8.x.

Pending OpenSSL 1.0.2p release.

Ref: https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/ Ref: https://github.com/nodejs/node/pull/21345 Upstream: https://github.com/openssl/openssl/commit/949ff366

Original commit message:

Add blinding to an ECDSA signature

Keegan Ryan (NCC Group) has demonstrated a side channel attack on an
ECDSA signature operation. During signing the signer calculates:

s:= k^-1 * (m + r * priv_key) mod order

The addition operation above provides a sufficient signal for a
flush+reload attack to derive the private key given sufficient signature
operations.

As a mitigation (based on a suggestion from Keegan) we add blinding to
the operation so that:

s := k^-1 * blind^-1 (blind * m + blind * r * priv_key) mod order

Since this attack is a localhost side channel only no CVE is assigned.

Reviewed-by: Rich Salz <rsalz@openssl.org>

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