A rather late comment, On 05/10/2020 13:16, Jeff King wrote: > On Mon, Oct 05, 2020 at 03:17:51AM -0400, Jeff King wrote: > >> About 2 years ago as part of a security release we made it illegal to >> have a symlinked .gitmodules file (refusing it both in the index and via >> fsck). At the time we discussed (on the security list) outlawing >> symlinks for other .git files in the same way, but we decided not to do >> so as part of the security release, as it wasn't strictly necessary. Is this something that should be recorded in the documentation, either as a simple (sensible) limitation, or explicitly as a security related safety measure? I didn't see any changes to the .txt docs in the change list below. Philip >> >> We publicly revisited the topic in: >> >> https://lore.kernel.org/git/20190114230902.GG162110@xxxxxxxxxx/ >> >> but there were a few fixes needed, and it got forgotten. So here it is >> again, with those fixes: >> [...] > And here's a v2 incorporating feedback from Jonathan. There are no > substantial changes in the code. Most of the fixes are cosmetic, but the > tests are beefed up a bit, as well: > > - we now test that ntfs and hfs names are matched via fsck and > verify_path() for all file types. The bulk of this is in a new patch > 5, and the final patches are adjusted to use the new helper. > > - we confirm that read-tree doesn't write the forbidden entry into the > index (in addition to seeing that it complains) > > - the test script name is now "bad-dotgitx" instead of the vague > "bad-meta-files" > > - whitespace, typo-fixes, clarity, etc; the range diff is below > > [1/8]: fsck_tree(): fix shadowed variable > [2/8]: fsck_tree(): wrap some long lines > [3/8]: t7415: rename to expand scope > [4/8]: t7450: test verify_path() handling of gitmodules > [5/8]: t7450: test .gitmodules symlink matching against obscured names > [6/8]: t0060: test obscured .gitattributes and .gitignore matching > [7/8]: verify_path(): disallow symlinks in .gitattributes and .gitignore > [8/8]: fsck: complain when .gitattributes or .gitignore is a symlink > > fsck.c | 79 +++++++++++---- > read-cache.c | 12 ++- > t/helper/test-path-utils.c | 41 +++++--- > t/t0060-path-utils.sh | 20 ++++ > ...le-names.sh => t7450-bad-dotgitx-files.sh} | 99 +++++++++++++------ > 5 files changed, 187 insertions(+), 64 deletions(-) > rename t/{t7415-submodule-names.sh => t7450-bad-dotgitx-files.sh} (73%) > > 1: d4c4b98188 ! 1: 78689a44ba fsck_tree(): fix shadowed variable > @@ Commit message > > Let's rename both variables in the function to avoid confusion. This > makes the diff a little noisy (e.g., all of the report() calls outside > - the loop wee already correct but need touched), but makes sure we catch > - all cases and will avoid similar confusion in the future. > + the loop were already correct but need to be touched), but makes sure we > + catch all cases and will avoid similar confusion in the future. > + > + Note that our test change removes the comment about translation. It was > + arguably confusing since 674ba34038 (fsck: mark strings for translation, > + 2018-11-10); we wouldn't translate gitmodulesSymlink, but it did get > + removed by GETTEXT_POISON because that feature eats embedded > + %s characters. But certainly after this patch, when we look for the > + "tree %s: %s" format, we could get foiled by translation. > > Signed-off-by: Jeff King <peff@xxxxxxxx> > > @@ t/t7415-submodule-names.sh: test_expect_success 'fsck detects symlinked .gitmodu > + tree=$(git mktree <bad-tree) && > > # Check not only that we fail, but that it is due to the > - # symlink detector; this grep string comes from the config > - # variable name and will not be translated. > +- # symlink detector; this grep string comes from the config > +- # variable name and will not be translated. > ++ # symlink detector > test_must_fail git fsck 2>output && > - test_i18ngrep gitmodulesSymlink output > + test_i18ngrep "tree $tree: gitmodulesSymlink" output > 2: 29d0d3af44 = 2: b1f7ec465c fsck_tree(): wrap some long lines > 3: 8679f0b2f2 ! 3: d26ef683fd t7415: rename to expand scope > @@ Commit message > > Signed-off-by: Jeff King <peff@xxxxxxxx> > > - ## t/t7415-submodule-names.sh => t/t7450-bad-meta-files.sh ## > + ## t/t7415-submodule-names.sh => t/t7450-bad-dotgitx-files.sh ## > @@ > #!/bin/sh > > 4: 84e58f7f46 ! 4: 493a4c79a3 t7450: test verify_path() handling of gitmodules > @@ Commit message > > Signed-off-by: Jeff King <peff@xxxxxxxx> > > - ## t/t7450-bad-meta-files.sh ## > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'index-pack --strict works for non-repo pack' ' > + ## t/t7450-bad-dotgitx-files.sh ## > +@@ t/t7450-bad-dotgitx-files.sh: test_expect_success 'index-pack --strict works for non-repo pack' ' > grep gitmodulesName output > ' > > -test_expect_success 'fsck detects symlinked .gitmodules file' ' > -+test_expect_success 'create repo with symlinked .gitmodules file' ' > ++test_expect_success 'set up repo with symlinked .gitmodules file' ' > git init symlink && > ( > cd symlink && > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'fsck detects symlinked .gitmodules file' ' > +@@ t/t7450-bad-dotgitx-files.sh: test_expect_success 'fsck detects symlinked .gitmodules file' ' > { > printf "100644 blob $content\t$tricky\n" && > printf "120000 blob $target\t.gitmodules\n" > @@ t/t7450-bad-meta-files.sh: test_expect_success 'fsck detects symlinked .gitmodul > + cd symlink && > > # Check not only that we fail, but that it is due to the > - # symlink detector; this grep string comes from the config > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'fsck detects symlinked .gitmodules file' ' > + # symlink detector > +@@ t/t7450-bad-dotgitx-files.sh: test_expect_success 'fsck detects symlinked .gitmodules file' ' > ) > ' > > -+test_expect_success 'refuse to load symlinked .gitmodule into index' ' > ++test_expect_success 'refuse to load symlinked .gitmodules into index' ' > + test_must_fail git -C symlink read-tree $tree 2>err && > -+ test_i18ngrep "invalid path.*gitmodules" err > ++ test_i18ngrep "invalid path.*gitmodules" err && > ++ git -C symlink ls-files >out && > ++ test_must_be_empty out > +' > + > test_expect_success 'fsck detects non-blob .gitmodules' ' > -: ---------- > 5: db5e78ff5b t7450: test .gitmodules symlink matching against obscured names > 5: e141e49a5b ! 6: b5962a75a4 t0060: test obscured .gitattributes and .gitignore matching > @@ t/helper/test-path-utils.c: static struct test_data dirname_data[] = { > + if (!strcmp("--not", *argv)) > + expect = !expect; > + else if (expect != (is_hfs(*argv) || is_ntfs(*argv))) > -+ res = error("'%s' is %s.%s", *argv, > -+ expect ? "not " : "", x); > ++ res = error("'%s' is %s.git%s", *argv, > ++ expect ? "not " : "", x); > + else > -+ fprintf(stderr, "ok: '%s' is %s.%s\n", > ++ fprintf(stderr, "ok: '%s' is %s.git%s\n", > + *argv, expect ? "" : "not ", x); > + } > + return !!res; > @@ t/helper/test-path-utils.c: int cmd__path_utils(int argc, const char **argv) > - fprintf(stderr, "ok: '%s' is %s.gitmodules\n", > - argv[i], expect ? "" : "not "); > - return !!res; > -+ return check_dotgitx("gitmodules", argv + 2, > ++ return check_dotgitx("modules", argv + 2, > + is_hfs_dotgitmodules, > + is_ntfs_dotgitmodules); > + } > + if (argc > 2 && !strcmp(argv[1], "is_dotgitignore")) { > -+ return check_dotgitx("gitignore", argv + 2, > ++ return check_dotgitx("ignore", argv + 2, > + is_hfs_dotgitignore, > + is_ntfs_dotgitignore); > + } > + if (argc > 2 && !strcmp(argv[1], "is_dotgitattributes")) { > -+ return check_dotgitx("gitattributes", argv + 2, > ++ return check_dotgitx("attributes", argv + 2, > + is_hfs_dotgitattributes, > + is_ntfs_dotgitattributes); > } > 6: d214bbd8ec ! 7: e4ec698a5b verify_path(): disallow symlinks in .gitattributes and .gitignore > @@ Commit message > 0fc333ba20 (is_hfs_dotgit: match other .git files, 2018-05-02), which > were done as part of the series touching .gitmodules. > > + No tests yet, as we'll add them in a subsequent patch once we have fsck > + support, too. > + > Signed-off-by: Jeff King <peff@xxxxxxxx> > > ## read-cache.c ## > @@ read-cache.c: int verify_path(const char *path, unsigned mode) > return 0; > } > } > - > - ## t/t7450-bad-meta-files.sh ## > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'git dirs of sibling submodules must not be nested' ' > - test_i18ngrep "is inside git dir" err > - ' > - > -+test_expect_success 'create repo with symlinked .gitattributes file' ' > -+ git init symlink-attr && > -+ target=$(echo target | git -C symlink-attr hash-object -w --stdin) && > -+ tree=$( > -+ printf "120000 blob $target\t.gitattributes\n" | > -+ git -C symlink-attr mktree > -+ ) > -+' > -+ > -+test_expect_success 'refuse to load symlinked .gitattributes into index' ' > -+ test_must_fail git -C symlink-attr read-tree $tree 2>err && > -+ test_i18ngrep "invalid path.*gitattributes" err > -+' > -+ > -+test_expect_success 'create repo with symlinked .gitignore file' ' > -+ git init symlink-ignore && > -+ target=$(echo target | git -C symlink-ignore hash-object -w --stdin) && > -+ tree=$( > -+ printf "120000 blob $target\t.gitignore\n" | > -+ git -C symlink-ignore mktree > -+ ) > -+' > -+ > -+test_expect_success 'refuse to load symlinked .gitignore into index' ' > -+ test_must_fail git -C symlink-ignore read-tree $tree 2>err && > -+ test_i18ngrep "invalid path.*gitignore" err > -+' > -+ > -+ > - test_done > 7: 49423d03b5 ! 8: 58c9ce0f3c fsck: complain when .gitattributes or .gitignore is a symlink > @@ Commit message > check to fsck, which matches how we handle .gitmodules symlinks, via > b7b1fca175 (fsck: complain when .gitmodules is a symlink, 2018-05-04). > > - Note that we won't add these to the existing gitmodules block. Its logic > - is a bit more complicated, as we also check the content of non-symlink > - instances we find. But for these new files, there is no content check; > - we're just looking at the name and mode of the tree entry (and we can > - avoid even the complicated name checks in the common case that the mode > - doesn't indicate a symlink). > + Note that we won't add these to the existing gitmodules block. The logic > + for gitmodules is a bit more complicated, as we also check the content > + of non-symlink instances we find. But for these new files, there is no > + content check; we're just looking at the name and mode of the tree entry > + (and we can avoid even the complicated name checks in the common case > + that the mode doesn't indicate a symlink). > + > + We can reuse the test helper function we defined for .gitmodules, > + though (and this covers the verify_path() change from the previous > + commit, as well). > > Signed-off-by: Jeff King <peff@xxxxxxxx> > > @@ fsck.c: static int fsck_tree(const struct object_id *tree_oid, > while (backslash) { > backslash++; > > - ## t/t7450-bad-meta-files.sh ## > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'refuse to load symlinked .gitattributes into index' ' > - test_i18ngrep "invalid path.*gitattributes" err > - ' > + ## t/t7450-bad-dotgitx-files.sh ## > +@@ t/t7450-bad-dotgitx-files.sh: check_forbidden_symlink gitmodules vanilla .gitmodules > + check_forbidden_symlink gitmodules ntfs ".gitmodules ." > + check_forbidden_symlink gitmodules hfs ".${u200c}gitmodules" > > -+test_expect_success 'fsck detects symlinked .gitattributes file' ' > -+ test_must_fail git -C symlink-attr fsck 2>err && > -+ test_i18ngrep "tree $tree: gitattributesSymlink" err > -+' > ++check_forbidden_symlink gitattributes vanilla .gitattributes > ++check_forbidden_symlink gitattributes ntfs ".gitattributes ." > ++check_forbidden_symlink gitattributes hfs ".${u200c}gitattributes" > + > - test_expect_success 'create repo with symlinked .gitignore file' ' > - git init symlink-ignore && > - target=$(echo target | git -C symlink-ignore hash-object -w --stdin) && > -@@ t/t7450-bad-meta-files.sh: test_expect_success 'refuse to load symlinked .gitignore into index' ' > - test_i18ngrep "invalid path.*gitignore" err > - ' > - > -+test_expect_success 'fsck detects symlinked .gitignore file' ' > -+ test_must_fail git -C symlink-ignore fsck 2>err && > -+ test_i18ngrep "tree $tree: gitignoreSymlink" err > -+' > - > - test_done > ++check_forbidden_symlink gitignore vanilla .gitignore > ++check_forbidden_symlink gitignore ntfs ".gitignore ." > ++check_forbidden_symlink gitignore hfs ".${u200c}gitignore" > ++ > + test_expect_success 'fsck detects non-blob .gitmodules' ' > + git init non-blob && > + (
