This series adds a build-time knob to allow selecting an alternative SHA-1 implementation for non-cryptographic hashing within Git, starting with the `hashwrite()` family of functions. This version is a more size-able reroll from the first two rounds, which updates pack-objects to use a (hardened) version of `finalize_object_file()`, that is now sensitive to checksum collisions. Peff and I wrote the first four (new) patches together, and I feel confident now that we're in a good spot to address the concerns raised in [1]. Thanks in advance for your review! [1]: https://lore.kernel.org/git/20240905202707.GA2602440@xxxxxxxxxxxxxxxxxxxxxxx/ Taylor Blau (9): finalize_object_file(): check for name collision before renaming finalize_object_file(): refactor unlink_or_warn() placement finalize_object_file(): implement collision check pack-objects: use finalize_object_file() to rename pack/idx/etc i5500-git-daemon.sh: use compile-able version of Git without OpenSSL sha1: do not redefine `platform_SHA_CTX` and friends hash.h: scaffolding for _fast hashing variants Makefile: allow specifying a SHA-1 for non-cryptographic uses csum-file.c: use fast SHA-1 implementation when available Makefile | 25 ++++++ block-sha1/sha1.h | 2 + csum-file.c | 18 ++--- hash.h | 72 +++++++++++++++++ object-file.c | 110 +++++++++++++++++++++++++- pack-write.c | 7 +- sha1/openssl.h | 2 + sha1dc_git.h | 3 + t/interop/i5500-git-daemon.sh | 2 +- t/t5303-pack-corruption-resilience.sh | 7 +- 10 files changed, 230 insertions(+), 18 deletions(-) Range-diff against v2: -: ----------- > 1: 738b1eb17b4 finalize_object_file(): check for name collision before renaming -: ----------- > 2: e1c2c39711f finalize_object_file(): refactor unlink_or_warn() placement -: ----------- > 3: 0feee5d1d4f finalize_object_file(): implement collision check -: ----------- > 4: 620dde48a9d pack-objects: use finalize_object_file() to rename pack/idx/etc -: ----------- > 5: bfe992765cd i5500-git-daemon.sh: use compile-able version of Git without OpenSSL 1: e7cd23bf4cd = 6: 22863d9f6df sha1: do not redefine `platform_SHA_CTX` and friends 2: 3b5f21e4a62 = 7: 119c318d812 hash.h: scaffolding for _fast hashing variants 3: 02764de1395 = 8: 137ec30d68a Makefile: allow specifying a SHA-1 for non-cryptographic uses 4: 311fcc95960 = 9: 4018261366f csum-file.c: use fast SHA-1 implementation when available base-commit: 159f2d50e75c17382c9f4eb7cbda671a6fa612d1 -- 2.46.0.430.gca674632b70
