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authorJunio C Hamano <gitster@pobox.com>2021-10-25 16:06:57 -0700
committerJunio C Hamano <gitster@pobox.com>2021-10-25 16:06:57 -0700
commite058b1846c3b2051aab364d7b80e8c1696958a48 (patch)
tree0ff9597c8c3ebf2b70a98e5202de8bd67d5e01d7 /cache-tree.c
parent2c428e4205a50cee19669d5b73cc149ec2254a5d (diff)
parent5e311edfd3717373912df8239daba6903d78b7bd (diff)
downloadgit-e058b1846c3b2051aab364d7b80e8c1696958a48.tar.gz
Merge branch 'pw/sparse-cache-tree-verify-fix'
Recent sparse-index addition, namely any use of index_name_pos(), can expand sparse index entries and breaks any code that walks cache-tree or existing index entries. One such instance of such a breakage has been corrected. * pw/sparse-cache-tree-verify-fix: t1092: run "rebase --apply" without "-q" in testing sparse index: fix use-after-free bug in cache_tree_verify()
Diffstat (limited to 'cache-tree.c')
-rw-r--r--cache-tree.c37
1 files changed, 29 insertions, 8 deletions
diff --git a/cache-tree.c b/cache-tree.c
index f21bfc631c..79d168192d 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -827,10 +827,17 @@ static void verify_one_sparse(struct repository *r,
path->buf);
}
-static void verify_one(struct repository *r,
- struct index_state *istate,
- struct cache_tree *it,
- struct strbuf *path)
+/*
+ * Returns:
+ * 0 - Verification completed.
+ * 1 - Restart verification - a call to ensure_full_index() freed the cache
+ * tree that is being verified and verification needs to be restarted from
+ * the new toplevel cache tree.
+ */
+static int verify_one(struct repository *r,
+ struct index_state *istate,
+ struct cache_tree *it,
+ struct strbuf *path)
{
int i, pos, len = path->len;
struct strbuf tree_buf = STRBUF_INIT;
@@ -838,21 +845,30 @@ static void verify_one(struct repository *r,
for (i = 0; i < it->subtree_nr; i++) {
strbuf_addf(path, "%s/", it->down[i]->name);
- verify_one(r, istate, it->down[i]->cache_tree, path);
+ if (verify_one(r, istate, it->down[i]->cache_tree, path))
+ return 1;
strbuf_setlen(path, len);
}
if (it->entry_count < 0 ||
/* no verification on tests (t7003) that replace trees */
lookup_replace_object(r, &it->oid) != &it->oid)
- return;
+ return 0;
if (path->len) {
+ /*
+ * If the index is sparse and the cache tree is not
+ * index_name_pos() may trigger ensure_full_index() which will
+ * free the tree that is being verified.
+ */
+ int is_sparse = istate->sparse_index;
pos = index_name_pos(istate, path->buf, path->len);
+ if (is_sparse && !istate->sparse_index)
+ return 1;
if (pos >= 0) {
verify_one_sparse(r, istate, it, path, pos);
- return;
+ return 0;
}
pos = -pos - 1;
@@ -900,6 +916,7 @@ static void verify_one(struct repository *r,
oid_to_hex(&new_oid), oid_to_hex(&it->oid));
strbuf_setlen(path, len);
strbuf_release(&tree_buf);
+ return 0;
}
void cache_tree_verify(struct repository *r, struct index_state *istate)
@@ -908,6 +925,10 @@ void cache_tree_verify(struct repository *r, struct index_state *istate)
if (!istate->cache_tree)
return;
- verify_one(r, istate, istate->cache_tree, &path);
+ if (verify_one(r, istate, istate->cache_tree, &path)) {
+ strbuf_reset(&path);
+ if (verify_one(r, istate, istate->cache_tree, &path))
+ BUG("ensure_full_index() called twice while verifying cache tree");
+ }
strbuf_release(&path);
}