[PATCH 1/5] tree-walk: copy object ID before use

From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: git@vger.kernel.org
Cc: "Martin Ågren" <martin.agren@gmail.com>,
	"Junio C Hamano" <gitster@pobox.com>
Subject: [PATCH 1/5] tree-walk: copy object ID before use
Date: Thu, 10 Jan 2019 04:25:47 +0000	[thread overview]
Message-ID: <20190110042551.915769-2-sandals@crustytoothpaste.net> (raw)
In-Reply-To: <20190110042551.915769-1-sandals@crustytoothpaste.net>

In a future commit, the pointer returned by tree_entry_extract will
point into the struct tree_desc, causing its lifetime to be bound to
that of the struct tree_desc itself.  To ensure this code path keeps
working, copy the object_id into a local variable so that it lives long
enough.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 tree-walk.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tree-walk.c b/tree-walk.c
index 79bafbd1a2..1e040fc20e 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -498,10 +498,10 @@ static int find_tree_entry(struct tree_desc *t, const char *name, struct object_
 	int namelen = strlen(name);
 	while (t->size) {
 		const char *entry;
-		const struct object_id *oid;
+		struct object_id oid;
 		int entrylen, cmp;
 
-		oid = tree_entry_extract(t, &entry, mode);
+		oidcpy(&oid, tree_entry_extract(t, &entry, mode));
 		entrylen = tree_entry_len(&t->entry);
 		update_tree_entry(t);
 		if (entrylen > namelen)
@@ -512,7 +512,7 @@ static int find_tree_entry(struct tree_desc *t, const char *name, struct object_
 		if (cmp < 0)
 			break;
 		if (entrylen == namelen) {
-			oidcpy(result, oid);
+			oidcpy(result, &oid);
 			return 0;
 		}
 		if (name[entrylen] != '/')
@@ -520,10 +520,10 @@ static int find_tree_entry(struct tree_desc *t, const char *name, struct object_
 		if (!S_ISDIR(*mode))
 			break;
 		if (++entrylen == namelen) {
-			oidcpy(result, oid);
+			oidcpy(result, &oid);
 			return 0;
 		}
-		return get_tree_entry(oid, name + entrylen, result, mode);
+		return get_tree_entry(&oid, name + entrylen, result, mode);
 	}
 	return -1;
 }
