Commit Graph

8 Commits

Author SHA1 Message Date
David Benjamin
56f5eb9ffd Name constant-time functions more consistently.
I'm not sure why I separated "fixed" and "quick_ctx" names. That's
annoying and doesn't generalize well to, say, adding a bn_div_consttime
function for RSA keygen.

Change-Id: I751d52b30e079de2f0d37a952de380fbf2c1e6b7
Reviewed-on: https://boringssl-review.googlesource.com/26364
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2018-03-29 23:30:55 +00:00
David Benjamin
6f564afbdd Make BN_mod_*_quick constant-time.
As the EC code will ultimately want to use these in "words" form by way
of EC_FELEM, and because it's much easier, I've implement these as
low-level words-based functions that require all inputs have the same
width. The BIGNUM versions which RSA and, for now, EC calls are
implemented on top of that.

Unfortunately, doing such things in constant-time and accounting for
undersized inputs requires some scratch space, and these functions don't
take BN_CTX. So I've added internal bn_mod_*_quick_ctx functions that
take a BN_CTX and the old functions now allocate a bit unnecessarily.
RSA only needs lshift (for BN_MONT_CTX) and sub (for CRT), but the
generic EC code wants add as well.

The generic EC code isn't even remotely constant-time, and I hope to
ultimately use stack-allocated EC_FELEMs, so I've made the actual
implementations here implemented in "words", which is much simpler
anyway due to not having to take care of widths.

I've also gone ahead and switched the EC code to these functions,
largely as a test of their performance (an earlier iteration made the EC
code noticeably slower). These operations are otherwise not
performance-critical in RSA.

The conversion from BIGNUM to BIGNUM+BN_CTX should be dropped by the
static linker already, and the unused BIGNUM+BN_CTX functions will fall
off when EC_FELEM happens.

Update-Note: BN_mod_*_quick bounce on malloc a bit now, but they're not
    really used externally. The one caller I found was wpa_supplicant
    which bounces on malloc already. They appear to be implementing
    compressed coordinates by hand? We may be able to convince them to
    call EC_POINT_set_compressed_coordinates_GFp.

Bug: 233, 236
Change-Id: I2bf361e9c089e0211b97d95523dbc06f1168e12b
Reviewed-on: https://boringssl-review.googlesource.com/25261
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2018-02-06 01:16:04 +00:00
Adam Langley
45210dd4e2 Tidy up |ec_GFp_simple_point2oct| and friend.
(Just happened to see these as I went by.)

Change-Id: I348b163e6986bfca8b58e56885c35a813efe28f6
Reviewed-on: https://boringssl-review.googlesource.com/25725
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>
2018-02-05 04:40:59 +00:00
David Benjamin
1eddb4be29 Make EC_POINT_set_compressed_coordinates_GFp use BIGNUM directly.
All the messing around with field_mul and field_sqr does the same thing
as calling EC_GROUP_get_curve_GFp. This is in preparation for ultimately
moving the field elements to an EC_FELEM type.

Where we draw the BIGNUM / EC_FELEM line determines what EC_FELEM
operations we need. Since we don't care much about the performance of
this function, leave it in BIGNUM so we don't need an EC_FELEM
BN_mod_sqrt just yet. We can push it down later if we feel so inclined.

Change-Id: Iec07240d40828df6b7a29fd1f430e3b390d5f506
Reviewed-on: https://boringssl-review.googlesource.com/24686
Reviewed-by: Adam Langley <agl@google.com>
2018-01-08 19:40:21 +00:00
David Benjamin
cb16f17b36 Check EC_POINT/EC_GROUP compatibility more accurately.
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>
2017-10-28 08:02:50 +00:00
David Benjamin
808f832917 Run the comment converter on libcrypto.
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>
2017-08-18 21:49:04 +00:00
David Benjamin
4323e22793 Tidy up FIPS module dependencies.
This avoids depending the FIPS module on crypto/bytestring and moves
ECDSA_SIG_{new,free} into the module.

Change-Id: I7b45ef07f1140873a0da300501141b6ae272a5d9
Reviewed-on: https://boringssl-review.googlesource.com/15984
Reviewed-by: Adam Langley <agl@google.com>
2017-05-05 23:10:24 +00:00
Adam Langley
aacb72c1b7 Move ec/ and ecdsa/ into fipsmodule/
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>
2017-05-04 20:27:23 +00:00