doc: document the length requirements of output parameter. #714

rustyrussell · 2020-02-10T00:45:08Z

It's subtle, since it is actually only touched by hashfp (though
we assert it's non-NULL), but give explicit advice in the default
case.

Signed-off-by: Rusty Russell rusty@rustcorp.com.au

It's subtle, since it is actually only touched by hashfp (though we assert it's non-NULL), but give explicit advice in the default case. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

jonasnick

ACK 4b48a43

real-or-random

ACK 4b48a43 diff inspection

4b48a43 doc: document the length requirements of output parameter. (Rusty Russell) Pull request description: It's subtle, since it is actually only touched by hashfp (though we assert it's non-NULL), but give explicit advice in the default case. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> ACKs for top commit: jonasnick: ACK 4b48a43 real-or-random: ACK 4b48a43 diff inspection Tree-SHA512: d6bedb495e46b27ac9b558e77d814884d782ea78569a2296688eccf374bc880d13846546ad449c2a677865cf6ed56fcbc8be58c21f9daca5084831074e20d769

Summary: It's subtle, since it is actually only touched by hashfp (though we assert it's non-NULL), but give explicit advice in the default case. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> This is a backport of libsecp256k1 [[ bitcoin-core/secp256k1#714 | PR714 ]]. Test Plan: ninja check-secp256k1 Reviewers: #bitcoin_abc, Fabien Reviewed By: #bitcoin_abc, Fabien Differential Revision: https://reviews.bitcoinabc.org/D5389

e10439c scripted-diff: rename privkey with seckey in secp256k1 interface (Pieter Wuille) ca8bc42 Drop --disable-jni from libsecp256k1 configure options (Pieter Wuille) ddc2419 Update MSVC build config for libsecp256k1 (Pieter Wuille) 67f232b Squashed 'src/secp256k1/' changes from b19c000..2ed54da (Pieter Wuille) Pull request description: It's been abound a year since the subtree was updated. Here is a list of the included PRs: * bitcoin-core/secp256k1#755: Recovery signing: add to constant time test, and eliminate non ct operators * bitcoin-core/secp256k1#754: Fix uninit values passed into cmov * bitcoin-core/secp256k1#752: autoconf: Use ":" instead of "dnl" as a noop * bitcoin-core/secp256k1#750: Add macOS to the CI * bitcoin-core/secp256k1#701: Make ec_ arithmetic more consistent and add documentation * bitcoin-core/secp256k1#732: Retry if r is zero during signing * bitcoin-core/secp256k1#742: Fix typo in ecmult_const_impl.h * bitcoin-core/secp256k1#740: Make recovery/main_impl.h non-executable * bitcoin-core/secp256k1#735: build: fix OpenSSL EC detection on macOS * bitcoin-core/secp256k1#728: Suppress a harmless variable-time optimization by clang in memczero * bitcoin-core/secp256k1#722: Context isn't freed in the ECDH benchmark * bitcoin-core/secp256k1#700: Allow overriding default flags * bitcoin-core/secp256k1#708: Constant-time behaviour test using valgrind memtest. * bitcoin-core/secp256k1#710: Eliminate harmless non-constant time operations on secret data. * bitcoin-core/secp256k1#718: Clarify that a secp256k1_ecdh_hash_function must return 0 or 1 * bitcoin-core/secp256k1#714: doc: document the length requirements of output parameter. * bitcoin-core/secp256k1#682: Remove Java Native Interface * bitcoin-core/secp256k1#713: Docstrings * bitcoin-core/secp256k1#704: README: add a section for test coverage * bitcoin-core/secp256k1#709: Remove secret-dependant non-constant time operation in ecmult_const. * bitcoin-core/secp256k1#703: Overhaul README.md * bitcoin-core/secp256k1#689: Remove "except in benchmarks" exception for fp math * bitcoin-core/secp256k1#679: Add SECURITY.md * bitcoin-core/secp256k1#685: Fix issue where travis does not show the ./tests seed… * bitcoin-core/secp256k1#690: Add valgrind check to travis * bitcoin-core/secp256k1#678: Preventing compiler optimizations in benchmarks without a memory fence * bitcoin-core/secp256k1#688: Fix ASM setting in travis * bitcoin-core/secp256k1#684: Make no-float policy explicit * bitcoin-core/secp256k1#677: Remove note about heap allocation in secp256k1_ecmult_odd_multiples_table_storage_var * bitcoin-core/secp256k1#647: Increase robustness against UB in secp256k1_scalar_cadd_bit * bitcoin-core/secp256k1#664: Remove mention of ec_privkey_export because it doesn't exist * bitcoin-core/secp256k1#337: variable sized precomputed table for signing * bitcoin-core/secp256k1#661: Make ./configure string consistent * bitcoin-core/secp256k1#657: Fix a nit in the recovery tests * bitcoin-core/secp256k1#650: secp256k1/src/tests.c: Properly handle sscanf return value * bitcoin-core/secp256k1#654: Fix typo (∞) * bitcoin-core/secp256k1#583: JNI: fix use sig array * bitcoin-core/secp256k1#644: Avoid optimizing out a verify_check * bitcoin-core/secp256k1#652: README.md: update instruction to run tests * bitcoin-core/secp256k1#651: Fix typo in secp256k1_preallocated.h * bitcoin-core/secp256k1#640: scalar_impl.h: fix includes * bitcoin-core/secp256k1#655: jni: Use only Guava for hex encoding and decoding * bitcoin-core/secp256k1#634: Add a descriptive comment for secp256k1_ecmult_const. * bitcoin-core/secp256k1#631: typo in comment for secp256k1_ec_pubkey_tweak_mul () * bitcoin-core/secp256k1#629: Avoid calling _is_zero when _set_b32 fails. * bitcoin-core/secp256k1#630: Note intention of timing sidechannel freeness. * bitcoin-core/secp256k1#628: Fix ability to compile tests without -DVERIFY. * bitcoin-core/secp256k1#627: Guard memcmp in tests against mixed size inputs. * bitcoin-core/secp256k1#578: Avoid implementation-defined and undefined behavior when dealing with sizes * bitcoin-core/secp256k1#595: Allow to use external default callbacks * bitcoin-core/secp256k1#600: scratch space: use single allocation * bitcoin-core/secp256k1#592: Use trivial algorithm in ecmult_multi if scratch space is small * bitcoin-core/secp256k1#566: Enable context creation in preallocated memory * bitcoin-core/secp256k1#596: Make WINDOW_G configurable * bitcoin-core/secp256k1#561: Respect LDFLAGS and #undef STATIC_PRECOMPUTATION if using basic config * bitcoin-core/secp256k1#533: Make sure we're not using an uninitialized variable in secp256k1_wnaf_const(...) * bitcoin-core/secp256k1#617: Pass scalar by reference in secp256k1_wnaf_const() * bitcoin-core/secp256k1#619: Clear a copied secret key after negation * bitcoin-core/secp256k1#612: Allow field_10x26_arm.s to compile for ARMv7 architecture ACKs for top commit: real-or-random: ACK e10439c I verified the diff (subtree matches my local tree, manual inspection of other commits) but I didn't tested the resulting code fanquake: ACK e10439c Sjors: ACK e10439c jonasnick: reACK e10439c Tree-SHA512: eb6284a485da78e9d2ed3f771df85560d47c770ebf480a0d4121ab356ad26be101a2b973efe412f26e6c142bc1dbd2efbb5cc08774233e41918c59fe3dff3387

doc: document the length requirements of output parameter.

4b48a43

It's subtle, since it is actually only touched by hashfp (though we assert it's non-NULL), but give explicit advice in the default case. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

jonasnick approved these changes Feb 10, 2020

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real-or-random approved these changes Feb 10, 2020

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real-or-random merged commit 4b48a43 into bitcoin-core:master Feb 10, 2020

sipa mentioned this pull request Jun 9, 2020

Update libsecp256k1 subtree bitcoin/bitcoin#19228

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doc: document the length requirements of output parameter. #714

doc: document the length requirements of output parameter. #714

rustyrussell commented Feb 10, 2020

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doc: document the length requirements of output parameter. #714

doc: document the length requirements of output parameter. #714

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