Attempt to clarify what the SHAttered attack means in practice for
Git. The previous version of the text made no mention whatsoever of
Git already having a mitigation for this specific attack, which the
SHAttered researchers claim will detect cryptanalytic collision
attacks.
I may have gotten some of the nuances wrong, but as far as I know this
new text accurately summarizes the current situation with SHA-1 in
git. I.e. git doesn't really use SHA-1 anymore, it uses
Hardened-SHA-1 (they just so happen to produce the same outputs
99.99999999999...% of the time).
Thus the previous text was incorrect in asserting that:
[...]As a result [of SHAttered], SHA-1 cannot be considered
cryptographically secure any more[...]
That's not the case. We have a mitigation against SHAttered, *however*
we consider it prudent to move to work towards a NewHash should future
vulnerabilities in either SHA-1 or Hardened-SHA-1 emerge.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the "Repository format extension" to accurately describe what
happens with different versions of Git when they encounter NewHash
repositories, instead of only saying what happens with versions v2.7.0
and later.
See ab9cb76f66 ("Repository format version check.", 2005-11-25) and
00a09d57eb ("introduce "extensions" form of
core.repositoryformatversion", 2015-06-23) for the relevant changes to
the setup code where these variables are checked.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 11395a3b4b (test_must_be_empty: make sure the file exists, not
just empty, 2018-02-27) basically duplicated the 'test_path_is_file'
helper function in 'test_must_be_empty'.
Just call 'test_path_is_file' to avoid this code duplication.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One of the most interesting thing one can be interested in when
looking at performance test results is possible performance
regressions.
This new option makes it easy to spot such possible regressions.
This new option is named '--sort-by=regression' to make it
possible and easy to add other ways to sort the results, like for
example '--sort-by=utime'.
If we would like to sort according to how much the stime regressed
we could also add a new option called '--sort-by=regression:stime'.
Then '--sort-by=regression' could become a synonym for
'--sort-by=regression:rtime'.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new helper function will be reused in a subsequent
commit.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This will become an umbrella program that absorbs most [1] t/helper
programs in. By having a single executable binary we reduce disk usage
(libgit.a is replicated by every t/helper program) and shorten link
time a bit.
Running "make --jobs=1; du -sh t/helper" with ccache fully populated,
it takes 27 seconds and 277MB at the beginning of this series, 17
seconds and 42MB at the end.
[1] There are a couple programs that will not become part of
test-tool: test-line-buffer and test-svn-fe have extra
dependencies and test-fake-ssh's program name has to be a single
word for some ssh tests.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the $EMPTY_BLOB variable instead of hard-coding a hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses variables and command substitution for
blobs instead of hard-coded hashes.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of our tests start with the opening quote of the test body on the
same line as the test_expect_success call. Additionally, our tests are
usually indented with a single tab. Update this test to be the same as
most others, which will make it easier to use inline heredocs in the
future.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses variables for the revisions we're
checking out instead of hard-coded hashes.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses a variable consisting of the current
HEAD instead of a hard-coded hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses a variable consisting of the current
HEAD instead of a hard-coded hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The test enumerates reflog entries in an arbitrary order and then sorts
them. For SHA-1, this produces results that happen to sort in
alphabetical order, but for other hash algorithms they sort differently.
Ensure we sort the reflog entries in a hash-independent way by sorting
on the ref name instead of the object ID. Remove an assumption about
the length of a hash by using cut with the delimiter and field options
instead of the character range option.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses the computed blob value instead of
hard-coding a hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust the test so that it uses the $EMPTY_BLOB value instead of
hard-coding the hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
