@matheusbsbs / matheus-bagliano / commits / 45bb916248

setup: allow cwd=.git w/ bareRepository=explicit

The safe.bareRepository setting can be set to 'explicit' to disallow implicit uses of bare repositories, preventing an attack [1] where an artificial and malicious bare repository is embedded in another git repository. Unfortunately, some tooling uses myrepo/.git/ as the cwd when executing commands, and this is blocked when safe.bareRepository=explicit. Blocking is unnecessary, as git already prevents nested .git directories. Teach git to not reject uses of git inside of the .git directory: check if cwd is .git (or a subdirectory of it) and allow it even if safe.bareRepository=explicit. [1] https://github.com/justinsteven/advisories/blob/main/2022_git_buried_bare_repos_and_fsmonitor_various_abuses.md Signed-off-by: Kyle Lippincott <spectral@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Kyle Lippincott committed Jan 20, 2024 at 00:08 UTC 45bb91624804d3e3a70cfc1ba0eae5577f81fc38

2 files changed +10 -1

setup.c

+2 -1

@@ -1359,7 +1359,8 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,

1359

1360 if (is_git_directory(dir->buf)) {

1361 trace2_data_string("setup", NULL, "implicit-bare-repository", dir->buf);

1362 - if (get_allowed_bare_repo() == ALLOWED_BARE_REPO_EXPLICIT)

1362 + if (get_allowed_bare_repo() == ALLOWED_BARE_REPO_EXPLICIT &&

1363 + !ends_with_path_components(dir->buf, ".git"))

1364 return GIT_DIR_DISALLOWED_BARE;

1365 if (!ensure_valid_ownership(NULL, NULL, dir->buf, report))

1366 return GIT_DIR_INVALID_OWNERSHIP;

t/t0035-safe-bare-repository.sh

@@ -78,4 +78,12 @@ test_expect_success 'no trace when GIT_DIR is explicitly provided' '

78 expect_accepted_explicit "$pwd/outer-repo/bare-repo"

79 '

81 +test_expect_success 'no trace when "bare repository" is .git' '

82 + expect_accepted_implicit -C outer-repo/.git

83 +'

84 +

85 +test_expect_success 'no trace when "bare repository" is a subdir of .git' '

86 + expect_accepted_implicit -C outer-repo/.git/objects

87 +'

88 +

89 test_done