[PATCH v2 3/3] unpack-trees: detect mismatching number of cache-tree/index entries

From

Patrick Steinhardt <ps@pks.im>

Date

Oct 7, 2024, 04:38 UTC

Message-ID

<5e578c1f4161ba5c23fd5b27e792807b632e9c06.1728275640.git.ps@pks.im>

In-Reply-To

<cover.1728275640.git.ps@pks.im>

This also makes t4058 pass with the leak sanitizer enabled.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 t/t4058-diff-duplicates.sh | 7 +++++--
 unpack-trees.c             | 2 ++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/t/t4058-diff-duplicates.sh b/t/t4058-diff-duplicates.sh
index 3f602adb05..18e5ac88c3 100755
--- a/t/t4058-diff-duplicates.sh
+++ b/t/t4058-diff-duplicates.sh
@@ -10,6 +10,8 @@
 #   that the diff output isn't wildly unreasonable.
 
 test_description='test tree diff when trees have duplicate entries'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # make_tree_entry <mode> <mode> <sha1>
@@ -143,11 +145,12 @@ test_expect_success 'reset --hard does not segfault' '
 	test_grep "error: corrupted cache-tree has entries not present in index" err
 '
 
-test_expect_failure 'git diff HEAD does not segfault' '
+test_expect_success 'git diff HEAD does not segfault' '
 	git checkout base &&
 	GIT_TEST_CHECK_CACHE_TREE=false &&
 	git reset --hard &&
-	test_might_fail git diff HEAD
+	test_must_fail git diff HEAD 2>err &&
+	test_grep "error: corrupted cache-tree has entries not present in index" err
 '
 
 test_expect_failure 'can switch to another branch when status is empty' '
diff --git a/unpack-trees.c b/unpack-trees.c
index 21cc197d47..e10a9d1209 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -808,6 +808,8 @@ static int traverse_by_cache_tree(int pos, int nr_entries, int nr_names,
 
 	if (!o->merge)
 		BUG("We need cache-tree to do this optimization");
+	if (nr_entries + pos > o->src_index->cache_nr)
+		return error(_("corrupted cache-tree has entries not present in index"));
 
 	/*
 	 * Do what unpack_callback() and unpack_single_entry() normally

-- 
2.47.0.rc0.dirty