git/t/t7450-bad-git-dotfiles.sh
Jeff King 1cb12f3339 t7450: test .gitmodules symlink matching against obscured names
In t7450 we check that both verify_path() and fsck catch malformed
.gitmodules entries in trees. However, we don't check that we catch
filesystem-equivalent forms of these (e.g., ".GITMOD~1" on Windows).
Our name-matching functions are exercised well in t0060, but there's
nothing to test that we correctly call the matching functions from the
actual fsck and verify_path() code.

So instead of testing just .gitmodules, let's repeat our tests for a few
basic cases. We don't need to be exhaustive here (t0060 handles that),
but just make sure we hit one name of each type.

Besides pushing the tests into a function that takes the path as a
parameter, we'll need to do a few things:

  - adjust the directory name to accommodate the tests running multiple
    times

  - set core.protecthfs for index checks. Fsck always protects all types
    by default, but we want to be able to exercise the HFS routines on
    every system. Note that core.protectntfs is already the default
    these days, but it doesn't hurt to explicitly label our need for it.

  - we'll also take the filename ("gitmodules") as a parameter. All
    calls use the same name for now, but a future patch will extend this
    to handle other .gitfoo files. Note that our fake-content symlink
    destination is somewhat .gitmodules specific. But it isn't necessary
    for other files (which don't do a content check). And it happens to
    be a valid attribute and ignore file anyway.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-04 11:52:02 +09:00

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#!/bin/sh
test_description='check broken or malicious patterns in .git* files
Such as:
- presence of .. in submodule names;
Exercise the name-checking function on a variety of names, and then give a
real-world setup that confirms we catch this in practice.
- nested submodule names
- symlinked .gitmodules, etc
'
. ./test-lib.sh
. "$TEST_DIRECTORY"/lib-pack.sh
test_expect_success 'check names' '
cat >expect <<-\EOF &&
valid
valid/with/paths
EOF
git submodule--helper check-name >actual <<-\EOF &&
valid
valid/with/paths
../foo
/../foo
..\foo
\..\foo
foo/..
foo/../
foo\..
foo\..\
foo/../bar
EOF
test_cmp expect actual
'
test_expect_success 'create innocent subrepo' '
git init innocent &&
git -C innocent commit --allow-empty -m foo
'
test_expect_success 'submodule add refuses invalid names' '
test_must_fail \
git submodule add --name ../../modules/evil "$PWD/innocent" evil
'
test_expect_success 'add evil submodule' '
git submodule add "$PWD/innocent" evil &&
mkdir modules &&
cp -r .git/modules/evil modules &&
write_script modules/evil/hooks/post-checkout <<-\EOF &&
echo >&2 "RUNNING POST CHECKOUT"
EOF
git config -f .gitmodules submodule.evil.update checkout &&
git config -f .gitmodules --rename-section \
submodule.evil submodule.../../modules/evil &&
git add modules &&
git commit -am evil
'
# This step seems like it shouldn't be necessary, since the payload is
# contained entirely in the evil submodule. But due to the vagaries of the
# submodule code, checking out the evil module will fail unless ".git/modules"
# exists. Adding another submodule (with a name that sorts before "evil") is an
# easy way to make sure this is the case in the victim clone.
test_expect_success 'add other submodule' '
git submodule add "$PWD/innocent" another-module &&
git add another-module &&
git commit -am another
'
test_expect_success 'clone evil superproject' '
git clone --recurse-submodules . victim >output 2>&1 &&
! grep "RUNNING POST CHECKOUT" output
'
test_expect_success 'fsck detects evil superproject' '
test_must_fail git fsck
'
test_expect_success 'transfer.fsckObjects detects evil superproject (unpack)' '
rm -rf dst.git &&
git init --bare dst.git &&
git -C dst.git config transfer.fsckObjects true &&
test_must_fail git push dst.git HEAD
'
test_expect_success 'transfer.fsckObjects detects evil superproject (index)' '
rm -rf dst.git &&
git init --bare dst.git &&
git -C dst.git config transfer.fsckObjects true &&
git -C dst.git config transfer.unpackLimit 1 &&
test_must_fail git push dst.git HEAD
'
# Normally our packs contain commits followed by trees followed by blobs. This
# reverses the order, which requires backtracking to find the context of a
# blob. We'll start with a fresh gitmodules-only tree to make it simpler.
test_expect_success 'create oddly ordered pack' '
git checkout --orphan odd &&
git rm -rf --cached . &&
git add .gitmodules &&
git commit -m odd &&
{
pack_header 3 &&
pack_obj $(git rev-parse HEAD:.gitmodules) &&
pack_obj $(git rev-parse HEAD^{tree}) &&
pack_obj $(git rev-parse HEAD)
} >odd.pack &&
pack_trailer odd.pack
'
test_expect_success 'transfer.fsckObjects handles odd pack (unpack)' '
rm -rf dst.git &&
git init --bare dst.git &&
test_must_fail git -C dst.git unpack-objects --strict <odd.pack
'
test_expect_success 'transfer.fsckObjects handles odd pack (index)' '
rm -rf dst.git &&
git init --bare dst.git &&
test_must_fail git -C dst.git index-pack --strict --stdin <odd.pack
'
test_expect_success 'index-pack --strict works for non-repo pack' '
rm -rf dst.git &&
git init --bare dst.git &&
cp odd.pack dst.git &&
test_must_fail git -C dst.git index-pack --strict odd.pack 2>output &&
# Make sure we fail due to bad gitmodules content, not because we
# could not read the blob in the first place.
grep gitmodulesName output
'
check_dotx_symlink () {
name=$1
type=$2
path=$3
dir=symlink-$name-$type
test_expect_success "set up repo with symlinked $name ($type)" '
git init $dir &&
(
cd $dir &&
# Make the tree directly to avoid index restrictions.
#
# Because symlinks store the target as a blob, choose
# a pathname that could be parsed as a .gitmodules file
# to trick naive non-symlink-aware checking.
tricky="[foo]bar=true" &&
content=$(git hash-object -w ../.gitmodules) &&
target=$(printf "$tricky" | git hash-object -w --stdin) &&
{
printf "100644 blob $content\t$tricky\n" &&
printf "120000 blob $target\t$path\n"
} >bad-tree
) &&
tree=$(git -C $dir mktree <$dir/bad-tree)
'
test_expect_success "fsck detects symlinked $name ($type)" '
(
cd $dir &&
# Check not only that we fail, but that it is due to the
# symlink detector
test_must_fail git fsck 2>output &&
grep "tree $tree: ${name}Symlink" output
)
'
test_expect_success "refuse to load symlinked $name into index ($type)" '
test_must_fail \
git -C $dir \
-c core.protectntfs \
-c core.protecthfs \
read-tree $tree 2>err &&
grep "invalid path.*$name" err &&
git -C $dir ls-files -s >out &&
test_must_be_empty out
'
}
check_dotx_symlink gitmodules vanilla .gitmodules
check_dotx_symlink gitmodules ntfs ".gitmodules ."
check_dotx_symlink gitmodules hfs ".${u200c}gitmodules"
test_expect_success 'fsck detects non-blob .gitmodules' '
git init non-blob &&
(
cd non-blob &&
# As above, make the funny tree directly to avoid index
# restrictions.
mkdir subdir &&
cp ../.gitmodules subdir/file &&
git add subdir/file &&
git commit -m ok &&
git ls-tree HEAD | sed s/subdir/.gitmodules/ | git mktree &&
test_must_fail git fsck 2>output &&
test_i18ngrep gitmodulesBlob output
)
'
test_expect_success 'fsck detects corrupt .gitmodules' '
git init corrupt &&
(
cd corrupt &&
echo "[broken" >.gitmodules &&
git add .gitmodules &&
git commit -m "broken gitmodules" &&
git fsck 2>output &&
test_i18ngrep gitmodulesParse output &&
test_i18ngrep ! "bad config" output
)
'
test_expect_success MINGW 'prevent git~1 squatting on Windows' '
git init squatting &&
(
cd squatting &&
mkdir a &&
touch a/..git &&
git add a/..git &&
test_tick &&
git commit -m initial &&
modules="$(test_write_lines \
"[submodule \"b.\"]" "url = ." "path = c" \
"[submodule \"b\"]" "url = ." "path = d\\\\a" |
git hash-object -w --stdin)" &&
rev="$(git rev-parse --verify HEAD)" &&
hash="$(echo x | git hash-object -w --stdin)" &&
test_must_fail git update-index --add \
--cacheinfo 160000,$rev,d\\a 2>err &&
test_i18ngrep "Invalid path" err &&
git -c core.protectNTFS=false update-index --add \
--cacheinfo 100644,$modules,.gitmodules \
--cacheinfo 160000,$rev,c \
--cacheinfo 160000,$rev,d\\a \
--cacheinfo 100644,$hash,d./a/x \
--cacheinfo 100644,$hash,d./a/..git &&
test_tick &&
git -c core.protectNTFS=false commit -m "module"
) &&
test_must_fail git -c core.protectNTFS=false \
clone --recurse-submodules squatting squatting-clone 2>err &&
test_i18ngrep -e "directory not empty" -e "not an empty directory" err &&
! grep gitdir squatting-clone/d/a/git~2
'
test_expect_success 'git dirs of sibling submodules must not be nested' '
git init nested &&
test_commit -C nested nested &&
(
cd nested &&
cat >.gitmodules <<-EOF &&
[submodule "hippo"]
url = .
path = thing1
[submodule "hippo/hooks"]
url = .
path = thing2
EOF
git clone . thing1 &&
git clone . thing2 &&
git add .gitmodules thing1 thing2 &&
test_tick &&
git commit -m nested
) &&
test_must_fail git clone --recurse-submodules nested clone 2>err &&
test_i18ngrep "is inside git dir" err
'
test_done