Refactor HMAC implementations

Enterprise / PostgreSQL - Michael Paquier [paquier.xyz] - 3 April 2021 08:30 UTC

Similarly to the cryptohash implementations, this refactors the existing HMAC code into a single set of APIs that can be plugged with any crypto libraries PostgreSQL is built with (only OpenSSL currently). If there is no such libraries, a fallback implementation is available. Those new APIs are designed similarly to the existing cryptohash layer, so there is no real new design here, with the same logic around buffer bound checks and memory handling.

HMAC has a dependency on cryptohashes, so all the cryptohash types supported by cryptohash{_openssl}.c can be used with HMAC. This refactoring is an advantage mainly for SCRAM, that included its own implementation of HMAC with SHA256 without relying on the existing crypto libraries even if PostgreSQL was built with their support.

This code has been tested on Windows and Linux, with and without OpenSSL, across all the versions supported on HEAD from 1.1.1 down to 1.0.1. I have also checked that the implementations are working fine using some sample results, a custom extension of my own, and doing cross-checks across different major versions with SCRAM with the client and the backend.

Author: Michael Paquier

e6bdfd9700 Refactor HMAC implementations
configure | 2 +-
configure.ac | 2 +-
src/backend/libpq/auth-scram.c | 61 ++++----
src/backend/utils/resowner/resowner.c | 61 ++++++++
src/common/Makefile | 4 +-
src/common/hmac.c | 263 ++++++++++++++++++++++++++++++++++
src/common/hmac_openssl.c | 256 +++++++++++++++++++++++++++++++++
src/common/scram-common.c | 158 +++++---------------
src/include/common/hmac.h | 29 ++++
src/include/common/md5.h | 2 +
src/include/common/scram-common.h | 13 --
src/include/common/sha1.h | 2 +
src/include/pg_config.h.in | 6 +
src/include/utils/resowner_private.h | 7 +
src/interfaces/libpq/fe-auth-scram.c | 75 ++++++----
src/tools/msvc/Mkvcbuild.pm | 2 +
src/tools/msvc/Solution.pm | 4 +
src/tools/pgindent/typedefs.list | 2 +-
18 files changed, 749 insertions(+), 200 deletions(-)

Upstream: git.postgresql.org


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