Along the way, this allows us to tidy up the invariants associated with
EC_SCALAR. They were fuzzy around ec_point_mul_scalar and some
computations starting from the digest in ECDSA. The latter I've put into
the type system with EC_LOOSE_SCALAR.
As for the former, Andres points out that particular EC implementations
are only good for scalars within a certain range, otherwise you may need
extra work to avoid the doubling case. To simplify curve
implementations, we reduce them fully rather than do the looser bit size
check, so they can have the stronger precondition to work with.
Change-Id: Iff9a0404f89adf8f7f914f8e8246c9f3136453f1
Reviewed-on: https://boringssl-review.googlesource.com/23664
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
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None of the asymmetric crypto we inherented from OpenSSL is
constant-time because of BIGNUM. BIGNUM chops leading zeros off the
front of everything, so we end up leaking information about the first
word, in theory. BIGNUM functions additionally tend to take the full
range of inputs and then call into BN_nnmod at various points.
All our secret values should be acted on in constant-time, but k in
ECDSA is a particularly sensitive value. So, ecdsa_sign_setup, in an
attempt to mitigate the BIGNUM leaks, would add a couple copies of the
order.
This does not work at all. k is used to compute two values: k^-1 and kG.
The first operation when computing k^-1 is to call BN_nnmod if k is out
of range. The entry point to our tuned constant-time curve
implementations is to call BN_nnmod if the scalar has too many bits,
which this causes. The result is both corrections are immediately undone
but cause us to do more variable-time work in the meantime.
Replace all these computations around k with the word-based functions
added in the various preceding CLs. In doing so, replace the BN_mod_mul
calls (which internally call BN_nnmod) with Montgomery reduction. We can
avoid taking k^-1 out of Montgomery form, which combines nicely with
Brian Smith's trick in 3426d10119. Along
the way, we avoid some unnecessary mallocs.
BIGNUM still affects the private key itself, as well as the EC_POINTs.
But this should hopefully be much better now. Also it's 10% faster:
Before:
Did 15000 ECDSA P-224 signing operations in 1069117us (14030.3 ops/sec)
Did 18000 ECDSA P-256 signing operations in 1053908us (17079.3 ops/sec)
Did 1078 ECDSA P-384 signing operations in 1087853us (990.9 ops/sec)
Did 473 ECDSA P-521 signing operations in 1069835us (442.1 ops/sec)
After:
Did 16000 ECDSA P-224 signing operations in 1064799us (15026.3 ops/sec)
Did 19000 ECDSA P-256 signing operations in 1007839us (18852.2 ops/sec)
Did 1078 ECDSA P-384 signing operations in 1079413us (998.7 ops/sec)
Did 484 ECDSA P-521 signing operations in 1083616us (446.7 ops/sec)
Change-Id: I2a25e90fc99dac13c0616d0ea45e125a4bd8cca1
Reviewed-on: https://boringssl-review.googlesource.com/23075
Reviewed-by: Adam Langley <agl@google.com>
Change-Id: Id12ab478b6ba441fb1b6f4c2f9479384fc3fbdb6
Reviewed-on: https://boringssl-review.googlesource.com/23144
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
I still need to revive the original CL, but right now I'm interested in
giving every EC_GROUP an order_mont and having different ownership of
that field between built-in and custom groups is kind of a nuisance. If
I'm going to do that anyway, better to avoid computing the entire
EC_GROUP in one go.
I'm using some manual locking rather than CRYPTO_once here so that it
behaves well in the face of malloc errors. Not that we especially care,
but it was easy to do.
This speeds up our ECDH benchmark a bit which otherwise must construct the
EC_GROUP each time (matching real world usage).
Before:
Did 7619 ECDH P-224 operations in 1003190us (7594.8 ops/sec)
Did 7518 ECDH P-256 operations in 1060844us (7086.8 ops/sec)
Did 572 ECDH P-384 operations in 1055878us (541.7 ops/sec)
Did 264 ECDH P-521 operations in 1062375us (248.5 ops/sec)
After:
Did 8415 ECDH P-224 operations in 1066695us (7888.9 ops/sec)
Did 7952 ECDH P-256 operations in 1022819us (7774.6 ops/sec)
Did 572 ECDH P-384 operations in 1055817us (541.8 ops/sec)
Did 264 ECDH P-521 operations in 1060008us (249.1 ops/sec)
Bug: 20
Change-Id: I7446cd0a69a840551dcc2dfabadde8ee1e3ff3e2
Reviewed-on: https://boringssl-review.googlesource.com/23073
Reviewed-by: Adam Langley <agl@google.com>
Later code will take advantage of these invariants. Enforcing them on
custom curves avoids making them go through a custom codepath.
Change-Id: I23cee72a90c2e4846b41e03e6be26bc3abeb4a45
Reviewed-on: https://boringssl-review.googlesource.com/23072
Reviewed-by: Adam Langley <agl@google.com>
Currently we only check that the underlying EC_METHODs match, which
avoids the points being in different forms, but not that the points are
on the same curves. (We fixed the APIs early on so off-curve EC_POINTs
cannot be created.)
In particular, this comes up with folks implementating Java's crypto
APIs with ECDH_compute_key. These APIs are both unfortunate and should
not be mimicked, as they allow folks to mismatch the groups on the two
multiple EC_POINTs. Instead, ECDH APIs should take the public value as a
byte string.
Thanks also to Java's poor crypto APIs, we must support custom curves,
which makes this particularly gnarly. This CL makes EC_GROUP_cmp work
with custom curves and adds an additional subtle requirement to
EC_GROUP_set_generator.
Annoyingly, this change is additionally subtle because we now have a
reference cycle to hack around.
Change-Id: I2efbc4bd5cb65fee5f66527bd6ccad6b9d5120b9
Reviewed-on: https://boringssl-review.googlesource.com/22245
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
I really need to resurrect the CL to make them entirely static
(https://crbug.com/boringssl/20), but, in the meantime, to make
replacing the EC_METHOD pointer in EC_POINT with EC_GROUP not
*completely* insane, make them refcounted.
OpenSSL did not do this because their EC_GROUPs are mutable
(EC_GROUP_set_asn1_flag and EC_GROUP_set_point_conversion_form). Ours
are immutable but for the two-function dance around custom curves (more
of OpenSSL's habit of making their objects too complex), which is good
enough to refcount.
Change-Id: I3650993737a97da0ddcf0e5fb7a15876e724cadc
Reviewed-on: https://boringssl-review.googlesource.com/22244
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
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This reverts commit f6942f0d22.
Reason for revert: This doesn't actually work in clang-cl. I
forgot we didn't have the clang-cl try bots enabled! :-( I
believe __asm__ is still okay, but I'll try it by hand
tomorrow.
Original change's description:
> Use uint128_t and __asm__ in clang-cl.
>
> clang-cl does not define __GNUC__ but is still a functioning clang. We
> should be able to use our uint128_t and __asm__ code in it on Windows.
>
> Change-Id: I67310ee68baa0c0c947b2441c265b019ef12af7e
> Reviewed-on: https://boringssl-review.googlesource.com/22184
> Commit-Queue: Adam Langley <agl@google.com>
> Reviewed-by: Adam Langley <agl@google.com>
> CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
TBR=agl@google.com,davidben@google.com
Change-Id: I5c7e0391cd9c2e8cc0dfde37e174edaf5d17db22
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://boringssl-review.googlesource.com/22224
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
clang-cl does not define __GNUC__ but is still a functioning clang. We
should be able to use our uint128_t and __asm__ code in it on Windows.
Change-Id: I67310ee68baa0c0c947b2441c265b019ef12af7e
Reviewed-on: https://boringssl-review.googlesource.com/22184
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
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crypto/{asn1,x509,x509v3,pem} were skipped as they are still OpenSSL
style.
Change-Id: I3cd9a60e1cb483a981aca325041f3fbce294247c
Reviewed-on: https://boringssl-review.googlesource.com/19504
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
It's confusing to have both mont and mont_data on EC_GROUP. The
documentation was also wrong.
Change-Id: I4e2e3169ed79307018212fba51d015bbbe5c4227
Reviewed-on: https://boringssl-review.googlesource.com/10348
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
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Change-Id: I8512c6bfb62f1a83afc8f763d681bf5db3b4ceae
Reviewed-on: https://boringssl-review.googlesource.com/17144
Commit-Queue: Adam Langley <alangley@gmail.com>
Reviewed-by: David Benjamin <davidben@google.com>
The names in the P-224 code collided with the P-256 code and thus many
of the functions and constants in the P-224 code have been prefixed.
Change-Id: I6bcd304640c539d0483d129d5eaf1702894929a8
Reviewed-on: https://boringssl-review.googlesource.com/15847
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
