name-hash: don't reuse cache_entry in dir_entry
Stop reusing cache_entry in dir_entry; doing so causes a
use-after-free bug.
During merges, we free entries that we no longer need in the
destination index. But those entries might have also been stored in
the dir_entry cache, and when a later call to add_to_index found them,
they would be used after being freed.
To prevent this, change dir_entry to store a copy of the name instead
of a pointer to a cache_entry. This entails some refactoring of code
that expects the cache_entry.
Keith McGuigan <kmcguigan@twitter.com> diagnosed this bug and wrote
the initial patch, but this version does not use any of Keith's code.
Helped-by: Keith McGuigan <kmcguigan@twitter.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/name-hash.c b/name-hash.c
index 702cd05..332ba95 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -11,16 +11,16 @@
struct dir_entry {
struct hashmap_entry ent;
struct dir_entry *parent;
- struct cache_entry *ce;
int nr;
unsigned int namelen;
+ char name[FLEX_ARRAY];
};
static int dir_entry_cmp(const struct dir_entry *e1,
const struct dir_entry *e2, const char *name)
{
- return e1->namelen != e2->namelen || strncasecmp(e1->ce->name,
- name ? name : e2->ce->name, e1->namelen);
+ return e1->namelen != e2->namelen || strncasecmp(e1->name,
+ name ? name : e2->name, e1->namelen);
}
static struct dir_entry *find_dir_entry(struct index_state *istate,
@@ -41,14 +41,6 @@
* closing slash. Despite submodules being a directory, they never
* reach this point, because they are stored
* in index_state.name_hash (as ordinary cache_entries).
- *
- * Note that the cache_entry stored with the dir_entry merely
- * supplies the name of the directory (up to dir_entry.namelen). We
- * track the number of 'active' files in a directory in dir_entry.nr,
- * so we can tell if the directory is still relevant, e.g. for git
- * status. However, if cache_entries are removed, we cannot pinpoint
- * an exact cache_entry that's still active. It is very possible that
- * multiple dir_entries point to the same cache_entry.
*/
struct dir_entry *dir;
@@ -63,10 +55,10 @@
dir = find_dir_entry(istate, ce->name, namelen);
if (!dir) {
/* not found, create it and add to hash table */
- dir = xcalloc(1, sizeof(struct dir_entry));
+ dir = xcalloc(1, sizeof(struct dir_entry) + namelen + 1);
hashmap_entry_init(dir, memihash(ce->name, namelen));
dir->namelen = namelen;
- dir->ce = ce;
+ strncpy(dir->name, ce->name, namelen);
hashmap_add(&istate->dir_hash, dir);
/* recursively add missing parent directories */
@@ -188,26 +180,36 @@
return slow_same_name(name, namelen, ce->name, len);
}
-struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen)
+int index_dir_exists(struct index_state *istate, const char *name, int namelen)
{
- struct cache_entry *ce;
struct dir_entry *dir;
lazy_init_name_hash(istate);
dir = find_dir_entry(istate, name, namelen);
- if (dir && dir->nr)
- return dir->ce;
+ return dir && dir->nr;
+}
- /*
- * It might be a submodule. Unlike plain directories, which are stored
- * in the dir-hash, submodules are stored in the name-hash, so check
- * there, as well.
- */
- ce = index_file_exists(istate, name, namelen, 1);
- if (ce && S_ISGITLINK(ce->ce_mode))
- return ce;
+void adjust_dirname_case(struct index_state *istate, char *name)
+{
+ const char *startPtr = name;
+ const char *ptr = startPtr;
- return NULL;
+ lazy_init_name_hash(istate);
+ while (*ptr) {
+ while (*ptr && *ptr != '/')
+ ptr++;
+
+ if (*ptr == '/') {
+ struct dir_entry *dir;
+
+ ptr++;
+ dir = find_dir_entry(istate, name, ptr - name + 1);
+ if (dir) {
+ memcpy((void *)startPtr, dir->name + (startPtr - name), ptr - startPtr);
+ startPtr = ptr;
+ }
+ }
+ }
}
struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
