From: Junio C Hamano <gitster@pobox.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
Geert Jansen <gerardu@amazon.com>,
Christian Couder <christian.couder@gmail.com>,
Nicolas Pitre <nico@fluxnic.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Petr Baudis <pasky@ucw.cz>
Subject: Re: [PATCH v3] index-pack: add ability to disable SHA-1 collision check
Date: Wed, 14 Nov 2018 16:09:17 +0900 [thread overview]
Message-ID: <xmqqftw4nnj6.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20181113201910.11518-1-avarab@gmail.com> (=?utf-8?B?IsOGdmFy?= =?utf-8?B?IEFybmZqw7Zyw7A=?= Bjarmason"'s message of "Tue, 13 Nov 2018 20:19:10 +0000")
Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> Add a new core.checkCollisions setting. On by default, it can be set
> to 'false' to disable the check for existing objects in sha1_object().
> ...
> diff --git a/builtin/index-pack.c b/builtin/index-pack.c
> index 2004e25da2..4a3508aa9f 100644
> --- a/builtin/index-pack.c
> +++ b/builtin/index-pack.c
> @@ -791,23 +791,24 @@ static void sha1_object(const void *data, struct object_entry *obj_entry,
> {
> void *new_data = NULL;
> int collision_test_needed = 0;
> + int do_coll_check = git_config_get_collision_check();
>
> assert(data || obj_entry);
>
> - if (startup_info->have_repository) {
> + if (do_coll_check && startup_info->have_repository) {
> read_lock();
> collision_test_needed =
> has_sha1_file_with_flags(oid->hash, OBJECT_INFO_QUICK);
> read_unlock();
> }
>
> - if (collision_test_needed && !data) {
> + if (do_coll_check && collision_test_needed && !data) {
> read_lock();
> if (!check_collison(obj_entry))
> collision_test_needed = 0;
> read_unlock();
> }
> - if (collision_test_needed) {
> + if (do_coll_check && collision_test_needed) {
If I am reading the patch correctly, The latter two changes are
totally unnecessary. c-t-needed is true only when dO-coll_check
allowed the initial "do we even have that object?" check to kick in
and never set otherwise.
I am not all that enthused to the idea of sending a wrong message to
our users, i.e. it is sometimes OK to sacrifice the security of
collision detection.
A small change like this is easy to adjust to apply to the codebase,
even after today's codebase undergoes extensive modifications; quite
honestly, I'd prefer not having to worry about it so close to the
pre-release feature freeze.
next prev parent reply other threads:[~2018-11-14 7:09 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 18:38 [RFC PATCH] index-pack: improve performance on NFS Jansen, Geert
2018-10-26 0:21 ` Junio C Hamano
2018-10-26 20:38 ` Ævar Arnfjörð Bjarmason
2018-10-27 7:26 ` Junio C Hamano
2018-10-27 9:33 ` Jeff King
2018-10-27 11:22 ` Ævar Arnfjörð Bjarmason
2018-10-28 22:50 ` [PATCH 0/4] index-pack: optionally turn off SHA-1 collision checking Ævar Arnfjörð Bjarmason
2018-10-30 2:49 ` Geert Jansen
2018-10-30 9:04 ` Junio C Hamano
2018-10-30 18:43 ` [PATCH v2 0/3] index-pack: test updates Ævar Arnfjörð Bjarmason
2018-11-13 20:19 ` [PATCH v3] index-pack: add ability to disable SHA-1 collision check Ævar Arnfjörð Bjarmason
2018-11-14 7:09 ` Junio C Hamano [this message]
2018-11-14 12:40 ` Ævar Arnfjörð Bjarmason
2018-10-30 18:43 ` [PATCH v2 1/3] pack-objects test: modernize style Ævar Arnfjörð Bjarmason
2018-10-30 18:43 ` [PATCH v2 2/3] pack-objects tests: don't leave test .git corrupt at end Ævar Arnfjörð Bjarmason
2018-10-30 18:43 ` [PATCH v2 3/3] index-pack tests: don't leave test repo dirty " Ævar Arnfjörð Bjarmason
2018-10-28 22:50 ` [PATCH 1/4] pack-objects test: modernize style Ævar Arnfjörð Bjarmason
2018-10-28 22:50 ` [PATCH 2/4] pack-objects tests: don't leave test .git corrupt at end Ævar Arnfjörð Bjarmason
2018-10-28 22:50 ` [PATCH 3/4] index-pack tests: don't leave test repo dirty " Ævar Arnfjörð Bjarmason
2018-10-28 22:50 ` [PATCH 4/4] index-pack: add ability to disable SHA-1 collision check Ævar Arnfjörð Bjarmason
2018-10-29 15:04 ` [RFC PATCH] index-pack: improve performance on NFS Jeff King
2018-10-29 15:09 ` Jeff King
2018-10-29 19:36 ` Ævar Arnfjörð Bjarmason
2018-10-29 23:27 ` Jeff King
2018-11-07 22:55 ` Geert Jansen
2018-11-08 12:02 ` Jeff King
2018-11-08 20:58 ` Geert Jansen
2018-11-08 21:18 ` Jeff King
2018-11-08 21:55 ` Geert Jansen
2018-11-08 22:20 ` Ævar Arnfjörð Bjarmason
2018-11-09 10:11 ` Ævar Arnfjörð Bjarmason
2018-11-12 14:31 ` Jeff King
2018-11-12 14:46 ` [PATCH 0/9] caching loose objects Jeff King
2018-11-12 14:46 ` [PATCH 1/9] fsck: do not reuse child_process structs Jeff King
2018-11-12 15:26 ` Derrick Stolee
2018-11-12 14:47 ` [PATCH 2/9] submodule--helper: prefer strip_suffix() to ends_with() Jeff King
2018-11-12 18:23 ` Stefan Beller
2018-11-12 14:48 ` [PATCH 3/9] rename "alternate_object_database" to "object_directory" Jeff King
2018-11-12 15:30 ` Derrick Stolee
2018-11-12 15:36 ` Jeff King
2018-11-12 19:41 ` Ramsay Jones
2018-11-12 14:48 ` [PATCH 4/9] sha1_file_name(): overwrite buffer instead of appending Jeff King
2018-11-12 15:32 ` Derrick Stolee
2018-11-12 14:49 ` [PATCH 5/9] handle alternates paths the same as the main object dir Jeff King
2018-11-12 15:38 ` Derrick Stolee
2018-11-12 15:46 ` Jeff King
2018-11-12 15:50 ` Derrick Stolee
2018-11-12 14:50 ` [PATCH 6/9] sha1-file: use an object_directory for " Jeff King
2018-11-12 15:48 ` Derrick Stolee
2018-11-12 16:09 ` Jeff King
2018-11-12 19:04 ` Stefan Beller
2018-11-22 17:42 ` Jeff King
2018-11-12 18:48 ` Stefan Beller
2018-11-12 14:50 ` [PATCH 7/9] object-store: provide helpers for loose_objects_cache Jeff King
2018-11-12 19:24 ` René Scharfe
2018-11-12 20:16 ` Jeff King
2018-11-12 14:54 ` [PATCH 8/9] sha1-file: use loose object cache for quick existence check Jeff King
2018-11-12 16:00 ` Derrick Stolee
2018-11-12 16:01 ` Ævar Arnfjörð Bjarmason
2018-11-12 16:21 ` Jeff King
2018-11-12 22:18 ` Ævar Arnfjörð Bjarmason
2018-11-12 22:30 ` Ævar Arnfjörð Bjarmason
2018-11-13 10:02 ` Ævar Arnfjörð Bjarmason
2018-11-14 18:21 ` René Scharfe
2018-12-02 10:52 ` René Scharfe
2018-12-03 22:04 ` Jeff King
2018-12-04 21:45 ` René Scharfe
2018-12-05 4:46 ` Jeff King
2018-12-05 6:02 ` René Scharfe
2018-12-05 6:51 ` Jeff King
2018-12-05 8:15 ` Jeff King
2018-12-05 18:41 ` René Scharfe
2018-12-05 20:17 ` Jeff King
2018-11-12 22:44 ` Geert Jansen
2018-11-27 20:48 ` René Scharfe
2018-12-01 19:49 ` Jeff King
2018-11-12 14:55 ` [PATCH 9/9] fetch-pack: drop custom loose object cache Jeff King
2018-11-12 19:25 ` René Scharfe
2018-11-12 19:32 ` Ævar Arnfjörð Bjarmason
2018-11-12 20:07 ` Jeff King
2018-11-12 20:13 ` René Scharfe
2018-11-12 16:02 ` [PATCH 0/9] caching loose objects Derrick Stolee
2018-11-12 19:10 ` Stefan Beller
2018-11-09 13:43 ` [RFC PATCH] index-pack: improve performance on NFS Ævar Arnfjörð Bjarmason
2018-11-09 16:08 ` Duy Nguyen
2018-11-10 14:04 ` Ævar Arnfjörð Bjarmason
2018-11-12 14:34 ` Jeff King
2018-11-12 22:58 ` Geert Jansen
2018-10-27 14:04 ` Duy Nguyen
2018-10-29 15:18 ` Jeff King
2018-10-29 0:48 ` Junio C Hamano
2018-10-29 15:20 ` Jeff King
2018-10-29 18:43 ` Ævar Arnfjörð Bjarmason
2018-10-29 21:34 ` Geert Jansen
2018-10-29 21:50 ` Jeff King
2018-10-29 22:21 ` Geert Jansen
2018-10-29 22:27 ` Jeff King
2018-10-29 22:35 ` Stefan Beller
2018-10-29 23:29 ` Jeff King
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